Mb-202 3(2-1)Basic MicrobiologyBSc.(Hons.) Agriculture

Course Contents

• Introduction to Microbiology ( microoranisms,types,classification,their

benificial and detrimental aspects)• History of Microbiology

– Contribution of scientists, Golden age of microbiology

• Branches of microbiology

Course Contents

• Differences between Prokaryotic and Eukaryotic cell

• A single Bacterial cell– cell types, their classification– Cell wall– Different structures which are external and

internal to cell wall e.g. Glycocalyx, flagella, cell membrane, ribosomes, ER, chromosomes etc.

Course Contents

• Bacterial growth, requirements, curves and measurements

• Bacterial endospore formation---------------Mid Term----------------

• Bacterial Genetics– Genes, genotype, phenotype, nuclear material– Nucleotides, genetic code, DNA & RNA structure

Course Contents

• DNA Replication process• Transcription• Translation• Introduction to viruses, their Classification

and Replication• Introduction to Fungi, Classification and

Importance

Course Contents

• Introduction to immune system and immunity

---------------Final---------------

Materials required for this class.

• Textbooks

Prescott's Principles of Microbiology by J Willey, Sherwood and Woolverton

Foundations in Microbiology by Talaro and Chess

Microbiology: An Introduction.by Totora, Funke and Case

M I C R O B I O L O G YWITH DISEASES BY BODY SYSTEM SECOND EDITION

An Introduction to An Introduction to MicrobiologyMicrobiology

What is a Microbe

• Smaller than 0.1mm• Includes bugs, things, germs, viruses,

protozoan, bacteria, animalcules, small parasites

Why study Microbiology

• Microbes are related to all life.– In all environments– Many beneficial aspects– Related to life processes (food web, nutrient

cycling)– Only a minority are pathogenic.– Most of our problems are caused by microbes

• Emerging infectious diseases (EID’s)– Weapons of mass destruction– New evolutionary features– Response to man encroaching on the

environment

• Can you name an example?

Microbes in research

• 10 trillion human cells 10x this number microbes

• Easy to grow• Biochemistry is

essentially the same• Simple and easy to

study

Bacteriology MycologyParasitologyImmunologyEpidemiologyBiotechnologyVirologyEnvironmental MicrobiologyBioremediation

Various disciplines of study within microbiology:

Diversity of Microbes

• Bacteria-single celled prokaryotes• Protozoa-eukaryotic, single celled, colonial,

many ways of nutrition• Fungi- absorb nutrients, single celled

filamentous• Viruses-acellular entities• Others- worms, insects

• Prokaryotes• Peptidoglycan cell

walls• Binary fission• For energy, use

organic chemicals, inorganic chemicals, or photosynthesis

Bacteria

Figure 1.1a

• Prokaryotic• Lack peptidoglycan• Live in extreme

environments• Include:

– Methanogens– Extreme halophiles– Extreme thermophiles

Archaea:

Halobacteria not from book

• Eukaryotes• Chitin cell walls• Use organic chemicals

for energy• Molds and

mushrooms are multicellular consisting of masses of mycelia, which are composed of filaments called hyphae

• Yeasts are unicellular

Fungi

Figure 1.1b

• Eukaryotes• Absorb or ingest

organic chemicals• May be motile via

pseudopods, cilia, or flagella

• Most free some parasites

Protozoa

Figure 1.1c

• Eukaryotes• Cellulose cell walls• Use photosynthesis for

energy (primary producers)

• Produce molecular oxygen and organic compounds

• Metabolically diverse

Algae

Figure 1.1d

• Acellular• Consist of DNA or

RNA core• Core is surrounded by

a protein coat• Coat may be enclosed

in a lipid envelope• Viruses are replicated

only when they are in a living host cell

Viruses

Figure 1.1e

• Eukaryote• Multicellular

animals• Parasitic

flatworms and round worms are called helminths.

• Microscopic stages in life cycles.

Multicellular Animal Parasites

Figure fluke

The Scientific Method

• Make an observation• Make a hypothesis• Test the hypothesis• Draw your conclusions• Repeat• Theory/Law

Scientific Method

Hypothesis

Laboratory experimentation or field Studies

Data collection and analysis

Conclusion, either reject or accept hypothesis

Theory or Law

Abiogenesis vs Biogenesis

“Spontaneous Generation” was an early belief that living things can arise from vital forces present in nonliving and decaying matter.

(Ex: maggots from meat or mushrooms from rotting wood

The alternative hypothesis that living organisms can arise only from preexisting life forms is called “Biogenesis”

• The hypothesis that living organisms arise from nonliving matter is called spontaneous generation. According to spontaneous generation, a “vital force’ forms life.

• The Alternative hypothesis, that the living organisms arise from preexisting life, is called biogenesis.

The Debate Over Spontaneous Generation

• 1668: Francisco Redi filled six jars with decaying meat.

Evidence Pros and Cons

Conditions Results3 jars covered with fine net

No maggots

3 open jars Maggots appeared

From where did the maggots come?What was the purpose of the sealed jars?Spontaneous generation or biogenesis?

• 1765: Lazzaro Spallanzani boiled nutrient solutions in flasks.

Evidence Pro and Con

Conditions ResultsNutrient broth placed in flask, heated, then sealed

No microbial growth

Spontaneous generation or biogenesis?

• Pasteur’s S-shaped flask kept microbes out but let air in.

The Theory of Biogenesis

Figure 1.3

A timeline of Microbiology

• Some highlights– 1665 Hooke– 1673 van Leeuwenhoek’s microscopes– 1735 Linnaeus Nomenclature– 1798 Jenner vaccine– 1857 Pasteur Fermentation– 1876 Koch germ theory of disease

Historical review of the Science of Microbiology

Robert Hook – 1665 – Englishman, used a primitive compound (two magnifying lenses)microscope, reported that life’s smallest units were little boxes – Cells, his workstarted the process of the development of the Cell theory of life

Hook’s microscope

Antoni Van Leeuwenhoek –1673 - probably the first person to observe living cells with a simple microscope, ground his own lenses and described what we know today as bacteria – rod shaped , spiral shaped , etc. “animalcules”

Antoni Van Leeuwenhoek

Francesco Redi – 1668 – opposed the prevailing theory of Spontaneous Generation, maggots in meat , He used covered jars to show that maggots came from flies –strong evidence against spontaneous generationNow we teach the theory of Biogenesis – Life comes from Life But issue of Spontaneous Generation was actively believed for many more years

Francesco Redi

Edward Jenner is credited with first vaccine – in epidemics of smallpox during the late 1700’s he observed that milk maids didn’t get the disease, cattle had a similar disease – cowpox, milk maids had cow pox lesions, but not small pox, he purposefully took scrapings from cowpox blister and scraped a 8 year old volunteer. With the material – child got mild illness but not small pox,

Vaccination comes from Latin word “vacca” meaning cow. Jenner laid the foundation for Pasteur’s later work with other vaccinations.

Jenner and vaccination

Pasteur – French sceintist that dealt the death blow to the spontaneous generation theory.

He devised the ingenious curved necked flasks that prevented contaminated air from reaching boiled beef broth – the broth remained uncontaminated even though exposed to the air

He was very lucky – no endopores present, or it would have failed(resitant to boiling)

1. He developed process we call Pasteuriztion – he heated wine to kill contaminating microbes – cured sick wine (today we heat treatment to kill pathogens in milk also)2. He proved that fermentation was caused by a microbe – yeast3. He developed vaccines for rabies and anthrax. Vaccines led to immunity to diseases that routinely killed many people, used to help people long before they understood how they even worked (science of Immunology)4. He began the revolution in science that led to the Golden Age of Microbiology (from 1857-1914)

Robert Koch - Developed Koch’s postulates – important technique for determining theactual microbial cause agent of a disease – more later, German, contemporary of Pasteur, several very important contributions1. He discovered the tuberculosis bug (tubercle bacillus, Mycobacterium tuberculosis)2. He discovered the cause of anthrax (Bacillus anthracis) – from blood of dead cattle, cultured bacteria in pure culture, injected bacteria in live cattle and they died, then again cultured the bacteria in pure culture. This led to the

Establishment of a procedure for determining microbial cause of disease

Koch’s postulates

Koch’s and Pasteur’s work helped establish the “Germ Theory of Disease” - thatmicroorganisms cause disease (in people, animals, and even plants)

Iwanowski 1892 - Discovered that plant disease can be caused by small organisms that were so

small they passed through filters , Tobacco mosaic virus (TMV) was later

identified as the cause - beginning of virology (Today we have discovered new and weird

things like viroids, prions)

Microbiology – Chapter 1

Paul Ehrlich, German doctor, wanted to find a “magic bullet” an agent that would kill the disease agent without hurting the patient. Developed Salvarsan, “salvation from syphilis”agent2. This was an arsenical – arsenic compound, that was effective against syphilis

Antimicrobial agent, medicine to treat a microbial disease, it was chemical – chemotherapy

• Syphilis spirochete: T. pallidum Paul Ehrlich

Joseph Lister – 1860’s, English surgeon that applied ideas of the germ theory to surgery, remembered the work of Semmelweis in Hungary in the 1840’s, if a Dr. would wash their hands childbed fever was prevented. He knew that phenol would kill bacteria; (phenol is the basic agent of today’s – Lysol)1. First antiseptic use in surgery, chemicals used as agents on tissue before surgery

(tissue treated with an antimicrobial agent – antiseptic, betadine) disinfectants are chemicals, used on a surface2. Also proved that microbes cause surgical infections

Semmelweis

Lister

• Antisepsis in surgery

Alexander Fleming - Scottish physician and bacteriologist - 1928Observed mold growing on a bacteria culture, there was a ring of clearing around the mold where the bacteria didn’t grow, the mold was later found to be a Penicillium species and the naturally secreted chemical was called penicillin, an antibiotic1. Antibiotics are natural agents2. Synthetic drugs are chemicals produced in labs (sulfas)3. Problems with them - toxicity, resistance, allergic reactions4. Fleming’s work - shelved until early WWII, sulfas were failing, needed penicillin to cure battle field wounds5. Now have thousands of antibiotics and synthetics (and a significant problem – resistance)

Flemming and Penicillium

Salk - Polio vaccine, 1950’s polio was a scary epidemic, Salk developed a vaccine by treating the virus with formalin (IPV) inactivated polio virusSabin 1963 live Polio virus vaccine, attenuated –altered virus, OPV-oral polio vaccineThe work done on polio revolutionized the science of virology and we are seeing the results today in advances with Hepatitis and HIV viral infections - tissueculture and other techniques

Watson and Crick, DNA, 1953

DNA Double helix• Double Helix

Jacob and Monod – 1965 Did research on RNA and protein synthesis in bacteria – last necessary step in understanding how genetics works on a cellular level (Replication, Transcription, Translation – protein synthesis – expression of traits)

The Golden Age of Microbiology

• 1857-1914• Beginning with Pasteur’s work,

discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs

•Classification

Microbiology

• Classification, Taxonomy, • Binomial Nomenclature

The Classification of Living Things

• Living organisms are assigned to groups based upon their similarities.

• Systematics is the discipline of identifying and classifying organisms.

Domains

• The highest – largest category, recent addition• 3 domains

– 1. Archaea – ancient “bacteria”, unicellular like bacteria, also simple cell structure (prokaryote – no nucleus) but have distinct metabolism (chemistry) allowing them to exist in “extreme” environments

– 2. Bacteria – unicellular, prokaryote, found everywhere (Old kingdom name – Monera)

– 3. Eukarya – unicellular to multicellular, complex and organized cells with nuclei and organelles (mitochondria)

Domain Archaea• Archaea are single-

celled organisms that lack a membrane-bound nucleus. - Prokaryote

• Archaea can be found in environments that are too hostile for other life forms.

Domain Bacteria

• Bacteria are single- celled organisms that lack a membrane-bound nucleus. (Prokaryote also)

• Bacteria are found almost everywhere on the planet Earth.

Domain Eukarya• The cells of all eukaryotes have a membrane-bound

nucleus. Members of the Domain Eukarya are further categorized into one of four Kingdoms. (know these kingdoms)

Microbiology

• Check your notes; Older 5 kingdom scheme is still widely used

• Monera – bacteria (Prokaryotic)• Protista – Protozoans (Eukaryotic)• Fungi - yeast, molds, etc. (Eukaryotic)• Plant – photosynthetic producers (Eukaryotic)• Animals – heterotrophic consumers

(Eukaryotic)

Categories of Classification

DomainKingdom

PhylumClass

OrderFamilyGenusSpecies

Categories of ClassificationDomain - Dumb

Kingdom - KingPhylum - Philip

Class – Came Order - Over

Family - For

Genus - Good

Species - __

Categories of Classification

DomainKingdomPhylumClassOrderFamilyGenusSpecies Least inclusive

Most inclusive

Scientific Names

• Binomial (two name) Genus first and first letter capitalized, then species not capitalized. If written or typed – either underline or italicize– Genus name, species name – Homo sapiens - italicized– Escherichia coli (Bacterial spp.) – underlined

– Or – Escherichia coli (italicized)