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This is the Power Point presentation that i used to deliver my popular lecture in University of Delhi on January 28 2009.
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COMMUNICATIONS IN LIVING ORGANISMS
Kambadur MuralidharDepartment of Zoology
University of DelhiDelhi-110007
University Popular Lecture series28th January 2009
WHAT IS A LIVING ORGANISM
bull Philosophy and Science seek answer to the same question ie what is the Truth about this universe
bull Science ie post-renaissance European science is constrained by the scientific method described by many especially Francis Bacon Rene des Carte and Karl Popper
bull While Physics constructs the physical reality of this universe through studies on the behavior of nature-structure and function Chemistry seeks the truth behind the objects in terms of their fundamental composition ie elements Chemistry believes that the interactions among these fundamental elements manifests as this sensory perceived world of materials and objects
bull Science is all about measurement but biology the science of life did not measure anything for many years It observed and recorded what living organisms do Later experimental Biology guided by the philosophy of Reductionism revealed to us the internal (PHYSIOLOGY) and external (BEHAVIOR) living processes Ecological and evolutionary phenomena are only consequences of these fundamental living processes
bull Living organisms exhibit a high degree of order in structure and functioning The very existence of life has a low probability given the physical principles of thermodynamics which reveals the fundamental behavior of universe as moving towards disorder than order ie entropic doom
bull Darwinrsquos Idea of lsquoEvolution by Natural Selectionrsquo is the greatest scientific concept in human history It pervades the whole of Biology as a means of interpretation of data and as an undercurrent story line Biology is a historical science revealing the story of life on Earth
bull Energy input and communication among components as well as between organisms and environment keep the living organism in a state where all physiological and behavioral processes occur like a well orchestrated symphony
bull Communication is simply a codified message It takes place say for example among organisms The most evolved of these is human language But we are not going to discuss this today for many reasons not the least is the fact that man is clever enough to use language to hide his thoughts and not to convey any message
bull The evolution of languages over time from a comparative linguistics perspective reveals the story of human migrations But this evolution is not due to selection pressure and hence we will not discuss this also
bull Communication in the living world can be classified for the sake of convenience into three types
bull ONE that between or among organisms of a group ( technically called a population) or between species It could be either intentional or unintentional and results in influenceeffect
bull TWO that between inanimate and animate world I do not like to call it even communication It is influential but not intentional ( for example photo period on living organisms) and
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
WHAT IS A LIVING ORGANISM
bull Philosophy and Science seek answer to the same question ie what is the Truth about this universe
bull Science ie post-renaissance European science is constrained by the scientific method described by many especially Francis Bacon Rene des Carte and Karl Popper
bull While Physics constructs the physical reality of this universe through studies on the behavior of nature-structure and function Chemistry seeks the truth behind the objects in terms of their fundamental composition ie elements Chemistry believes that the interactions among these fundamental elements manifests as this sensory perceived world of materials and objects
bull Science is all about measurement but biology the science of life did not measure anything for many years It observed and recorded what living organisms do Later experimental Biology guided by the philosophy of Reductionism revealed to us the internal (PHYSIOLOGY) and external (BEHAVIOR) living processes Ecological and evolutionary phenomena are only consequences of these fundamental living processes
bull Living organisms exhibit a high degree of order in structure and functioning The very existence of life has a low probability given the physical principles of thermodynamics which reveals the fundamental behavior of universe as moving towards disorder than order ie entropic doom
bull Darwinrsquos Idea of lsquoEvolution by Natural Selectionrsquo is the greatest scientific concept in human history It pervades the whole of Biology as a means of interpretation of data and as an undercurrent story line Biology is a historical science revealing the story of life on Earth
bull Energy input and communication among components as well as between organisms and environment keep the living organism in a state where all physiological and behavioral processes occur like a well orchestrated symphony
bull Communication is simply a codified message It takes place say for example among organisms The most evolved of these is human language But we are not going to discuss this today for many reasons not the least is the fact that man is clever enough to use language to hide his thoughts and not to convey any message
bull The evolution of languages over time from a comparative linguistics perspective reveals the story of human migrations But this evolution is not due to selection pressure and hence we will not discuss this also
bull Communication in the living world can be classified for the sake of convenience into three types
bull ONE that between or among organisms of a group ( technically called a population) or between species It could be either intentional or unintentional and results in influenceeffect
bull TWO that between inanimate and animate world I do not like to call it even communication It is influential but not intentional ( for example photo period on living organisms) and
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull Philosophy and Science seek answer to the same question ie what is the Truth about this universe
bull Science ie post-renaissance European science is constrained by the scientific method described by many especially Francis Bacon Rene des Carte and Karl Popper
bull While Physics constructs the physical reality of this universe through studies on the behavior of nature-structure and function Chemistry seeks the truth behind the objects in terms of their fundamental composition ie elements Chemistry believes that the interactions among these fundamental elements manifests as this sensory perceived world of materials and objects
bull Science is all about measurement but biology the science of life did not measure anything for many years It observed and recorded what living organisms do Later experimental Biology guided by the philosophy of Reductionism revealed to us the internal (PHYSIOLOGY) and external (BEHAVIOR) living processes Ecological and evolutionary phenomena are only consequences of these fundamental living processes
bull Living organisms exhibit a high degree of order in structure and functioning The very existence of life has a low probability given the physical principles of thermodynamics which reveals the fundamental behavior of universe as moving towards disorder than order ie entropic doom
bull Darwinrsquos Idea of lsquoEvolution by Natural Selectionrsquo is the greatest scientific concept in human history It pervades the whole of Biology as a means of interpretation of data and as an undercurrent story line Biology is a historical science revealing the story of life on Earth
bull Energy input and communication among components as well as between organisms and environment keep the living organism in a state where all physiological and behavioral processes occur like a well orchestrated symphony
bull Communication is simply a codified message It takes place say for example among organisms The most evolved of these is human language But we are not going to discuss this today for many reasons not the least is the fact that man is clever enough to use language to hide his thoughts and not to convey any message
bull The evolution of languages over time from a comparative linguistics perspective reveals the story of human migrations But this evolution is not due to selection pressure and hence we will not discuss this also
bull Communication in the living world can be classified for the sake of convenience into three types
bull ONE that between or among organisms of a group ( technically called a population) or between species It could be either intentional or unintentional and results in influenceeffect
bull TWO that between inanimate and animate world I do not like to call it even communication It is influential but not intentional ( for example photo period on living organisms) and
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull While Physics constructs the physical reality of this universe through studies on the behavior of nature-structure and function Chemistry seeks the truth behind the objects in terms of their fundamental composition ie elements Chemistry believes that the interactions among these fundamental elements manifests as this sensory perceived world of materials and objects
bull Science is all about measurement but biology the science of life did not measure anything for many years It observed and recorded what living organisms do Later experimental Biology guided by the philosophy of Reductionism revealed to us the internal (PHYSIOLOGY) and external (BEHAVIOR) living processes Ecological and evolutionary phenomena are only consequences of these fundamental living processes
bull Living organisms exhibit a high degree of order in structure and functioning The very existence of life has a low probability given the physical principles of thermodynamics which reveals the fundamental behavior of universe as moving towards disorder than order ie entropic doom
bull Darwinrsquos Idea of lsquoEvolution by Natural Selectionrsquo is the greatest scientific concept in human history It pervades the whole of Biology as a means of interpretation of data and as an undercurrent story line Biology is a historical science revealing the story of life on Earth
bull Energy input and communication among components as well as between organisms and environment keep the living organism in a state where all physiological and behavioral processes occur like a well orchestrated symphony
bull Communication is simply a codified message It takes place say for example among organisms The most evolved of these is human language But we are not going to discuss this today for many reasons not the least is the fact that man is clever enough to use language to hide his thoughts and not to convey any message
bull The evolution of languages over time from a comparative linguistics perspective reveals the story of human migrations But this evolution is not due to selection pressure and hence we will not discuss this also
bull Communication in the living world can be classified for the sake of convenience into three types
bull ONE that between or among organisms of a group ( technically called a population) or between species It could be either intentional or unintentional and results in influenceeffect
bull TWO that between inanimate and animate world I do not like to call it even communication It is influential but not intentional ( for example photo period on living organisms) and
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull Science is all about measurement but biology the science of life did not measure anything for many years It observed and recorded what living organisms do Later experimental Biology guided by the philosophy of Reductionism revealed to us the internal (PHYSIOLOGY) and external (BEHAVIOR) living processes Ecological and evolutionary phenomena are only consequences of these fundamental living processes
bull Living organisms exhibit a high degree of order in structure and functioning The very existence of life has a low probability given the physical principles of thermodynamics which reveals the fundamental behavior of universe as moving towards disorder than order ie entropic doom
bull Darwinrsquos Idea of lsquoEvolution by Natural Selectionrsquo is the greatest scientific concept in human history It pervades the whole of Biology as a means of interpretation of data and as an undercurrent story line Biology is a historical science revealing the story of life on Earth
bull Energy input and communication among components as well as between organisms and environment keep the living organism in a state where all physiological and behavioral processes occur like a well orchestrated symphony
bull Communication is simply a codified message It takes place say for example among organisms The most evolved of these is human language But we are not going to discuss this today for many reasons not the least is the fact that man is clever enough to use language to hide his thoughts and not to convey any message
bull The evolution of languages over time from a comparative linguistics perspective reveals the story of human migrations But this evolution is not due to selection pressure and hence we will not discuss this also
bull Communication in the living world can be classified for the sake of convenience into three types
bull ONE that between or among organisms of a group ( technically called a population) or between species It could be either intentional or unintentional and results in influenceeffect
bull TWO that between inanimate and animate world I do not like to call it even communication It is influential but not intentional ( for example photo period on living organisms) and
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull Living organisms exhibit a high degree of order in structure and functioning The very existence of life has a low probability given the physical principles of thermodynamics which reveals the fundamental behavior of universe as moving towards disorder than order ie entropic doom
bull Darwinrsquos Idea of lsquoEvolution by Natural Selectionrsquo is the greatest scientific concept in human history It pervades the whole of Biology as a means of interpretation of data and as an undercurrent story line Biology is a historical science revealing the story of life on Earth
bull Energy input and communication among components as well as between organisms and environment keep the living organism in a state where all physiological and behavioral processes occur like a well orchestrated symphony
bull Communication is simply a codified message It takes place say for example among organisms The most evolved of these is human language But we are not going to discuss this today for many reasons not the least is the fact that man is clever enough to use language to hide his thoughts and not to convey any message
bull The evolution of languages over time from a comparative linguistics perspective reveals the story of human migrations But this evolution is not due to selection pressure and hence we will not discuss this also
bull Communication in the living world can be classified for the sake of convenience into three types
bull ONE that between or among organisms of a group ( technically called a population) or between species It could be either intentional or unintentional and results in influenceeffect
bull TWO that between inanimate and animate world I do not like to call it even communication It is influential but not intentional ( for example photo period on living organisms) and
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull Darwinrsquos Idea of lsquoEvolution by Natural Selectionrsquo is the greatest scientific concept in human history It pervades the whole of Biology as a means of interpretation of data and as an undercurrent story line Biology is a historical science revealing the story of life on Earth
bull Energy input and communication among components as well as between organisms and environment keep the living organism in a state where all physiological and behavioral processes occur like a well orchestrated symphony
bull Communication is simply a codified message It takes place say for example among organisms The most evolved of these is human language But we are not going to discuss this today for many reasons not the least is the fact that man is clever enough to use language to hide his thoughts and not to convey any message
bull The evolution of languages over time from a comparative linguistics perspective reveals the story of human migrations But this evolution is not due to selection pressure and hence we will not discuss this also
bull Communication in the living world can be classified for the sake of convenience into three types
bull ONE that between or among organisms of a group ( technically called a population) or between species It could be either intentional or unintentional and results in influenceeffect
bull TWO that between inanimate and animate world I do not like to call it even communication It is influential but not intentional ( for example photo period on living organisms) and
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull Energy input and communication among components as well as between organisms and environment keep the living organism in a state where all physiological and behavioral processes occur like a well orchestrated symphony
bull Communication is simply a codified message It takes place say for example among organisms The most evolved of these is human language But we are not going to discuss this today for many reasons not the least is the fact that man is clever enough to use language to hide his thoughts and not to convey any message
bull The evolution of languages over time from a comparative linguistics perspective reveals the story of human migrations But this evolution is not due to selection pressure and hence we will not discuss this also
bull Communication in the living world can be classified for the sake of convenience into three types
bull ONE that between or among organisms of a group ( technically called a population) or between species It could be either intentional or unintentional and results in influenceeffect
bull TWO that between inanimate and animate world I do not like to call it even communication It is influential but not intentional ( for example photo period on living organisms) and
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull Communication is simply a codified message It takes place say for example among organisms The most evolved of these is human language But we are not going to discuss this today for many reasons not the least is the fact that man is clever enough to use language to hide his thoughts and not to convey any message
bull The evolution of languages over time from a comparative linguistics perspective reveals the story of human migrations But this evolution is not due to selection pressure and hence we will not discuss this also
bull Communication in the living world can be classified for the sake of convenience into three types
bull ONE that between or among organisms of a group ( technically called a population) or between species It could be either intentional or unintentional and results in influenceeffect
bull TWO that between inanimate and animate world I do not like to call it even communication It is influential but not intentional ( for example photo period on living organisms) and
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull The evolution of languages over time from a comparative linguistics perspective reveals the story of human migrations But this evolution is not due to selection pressure and hence we will not discuss this also
bull Communication in the living world can be classified for the sake of convenience into three types
bull ONE that between or among organisms of a group ( technically called a population) or between species It could be either intentional or unintentional and results in influenceeffect
bull TWO that between inanimate and animate world I do not like to call it even communication It is influential but not intentional ( for example photo period on living organisms) and
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull Communication in the living world can be classified for the sake of convenience into three types
bull ONE that between or among organisms of a group ( technically called a population) or between species It could be either intentional or unintentional and results in influenceeffect
bull TWO that between inanimate and animate world I do not like to call it even communication It is influential but not intentional ( for example photo period on living organisms) and
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull THREE that within an organism between cellstissues It is not intentional but results in regulation of a set point Let us understand this a little better
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull We refer to the systems of signals operating within a higher animal or plant and which is essentially inter-cellular communication The signals are mostly chemical but occasionally physical We will discuss the nature of these signals their origin and transmission their reception and decoding and how they bring about control regulation and order within the living organism
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
SIGNALS
A PHYSICAL TYPE i) LIGHT ii) PRESSURE (Mechanical) iii) VOLTAGE B CHEMICAL TYPE i) HORMONES ii) NEUROTRANSMITTERS iii) DRUGS (Xenobiotics)
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
Some Chemical Signals
bull Amino acid derivatives
bull Steroids
bull Lipids
bull Sugars
bull Gases like Nitric oxide and Hydrogen sulphide
bull Nucleosides like Adenosine
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
Major Divisions of the Nervous
System
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
Signals originating from hypothalamus
and pituitary gland are chemical in
nature They belong to a class of
chemicals called peptides and proteins
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
FEEDBACK INHIBITION AND FEEDFORWARD ACTIVATION ARE CHARECTERISTIC OF SIGNALING MECHANISMS IN OUR BODYTHERE IS
A NETWORK OF SIGNALING AND METABOLIC PATHWAYS WITH BUILT IN FEEDBACK LOOPS WHICH REGULATES LIVING PROCESSES
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
RECEPTOR IS A PHARMACOLOGICAL
TERM IT REFERS TO THE ENTITY IN
THE TARGET TISSUE WHICH EXHIBITS
THREE FUNCTIONS
i) Signal discrimination
ii) Signal transduction
iii) Signal amplification
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
bull Schematic representation of glycoprotein hormone receptor activation and the possible role of the Hin R
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
Transport and fate of major lipid substrates and metabolites
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
HEALTH AND UNHEALTH
In human history different societies have interpreted health and unhealth differently
The four humor idea of Hippocrates the panchaboota and tridosha ideas in Ayurveda system or the ideas of chrsquoiprana
and pneuma in Chinese Hindu and Greek
thoughts are some examples
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
The Placebo Effect
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
Mind (Brain)
Endocrine systemImmune system
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
The Neuroendocrine System Interacts with the Immune System
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
PHYSIOLOGY
Not Fat Just Well Covered
Adeacutelie penguins breed on the Antarctic ice and the chicks to survive must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching Raccurt et al investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34000 penguin pairs that breed on the Pointe Geologie archipelago They then measured the expression levels of transcription factors hormone receptors and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes In the first 2 weeks while a chick was at least partially protected by sheltering in a parentrsquos brood pouch growth hormone and 353-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development After day 15 when chicks had outgrown their brood pouches lipoprotein lipase PPAR1048576 and other factors associated with adipocyte aturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer This is similar to the changes seen in chicken cells but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat mdash CS
Am J Physiol Regul Integr Comp Physiol 295 101152ajpregu903712008 (2008)
SCIENCE 24 OCTOBER 2008 VOL 322 506
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
Gurdonrsquos experiment demonstrating that a differentiated cell contains all the genes needed for the development of a complete organism The nucleus of a frog egg was destroyed by ultraviolet irradiation and was replaced by the nucleus from the fully differentiated skin cells of another frog The egg with its transplanted nucleus was allowed to grow and it developed into a normal tadpole
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
SUMMARY
INFORMATION TRANSFER THROUGH SIGNALS RECEPTORS AND FEEDBACK LOOPS MEDIATE ALL PHYSIOLOGICAL AND BEHAVIOURAL PROCESSES ACHIEVING CORDINATION AND HEALTH DEFECT AT ANY STEP RESULTS IN UNHEALTH BUT ALSO SUGGESTS THERAPEUTIC APPROACHES
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
Feed back inhibition usually prevents dopamine overproduction but impairment of the feedback pathway in Huntingtonrsquos disease allows dopamine overproduction
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
Feedback motifs have important functions in signaling systems (A) Negative feedback can stabilize basal signaling levels limit maximal signaling output enable adaptive responses or create transient signal responses (B) Positive feedback can amplify signaling responses alter kinetics or create bistable switches (C) Mixtures of positive and negative feedback can create single pulses or oscillatorysignal outputs Mixed feedbacks can also trigger local signals self-propagating waves or cell polarization
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
Addition of extra feedback to core functions can be used to integrate key signaling characteristics or enhance the robustness of important functions (A) Combining two negative feedback loops can independently stabilize basal signaling and limit maximal signal output (B) Adding a negative feedback loop to the oscillator in Fig 2C can result in sharper spikes an increased input range over which oscillations occur and an increased output frequency range (C) A system made up of a dual fast and slow positive feedback loops can exhibit transient or persistent bistable states if the fast or both positive feedbacks are engaged
