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What is a Microbe
• Smaller than 0.1mm
• Includes bugs, things, germs, viruses, protozoan, bacteria, animalcules, small suckers
Nomenclature
• Carolus Linnaeus (1735)
• Genus species
• By custom once mentioned can be abbreviated with initial of genus followed by specific epithet. E. coli
• When two organisms share a common genus are related.
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
Microbes in research
• 10 trillion human cells 10x this number microbes
• Easy to grow• Biochemistry is
essentially the same• Simple and easy to
study
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
A timeline of Microbiology
• Fig 1.4• Some highlights
– 1665 Hooke– 1673 van Leeuwenhoek’s microscopes– 1735 Linnaeus Nomenclature– 1798 Jenner vaccine– 1857 Pasteur Fermentation– 1876 Koch germ theory of disease
The Golden Age of Microbiology
• 1857-1914
• Beginning with Pasteur’s work, discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs
• Pasteur showed that microbes are responsible for fermentation.
• Fermentation is the conversation of sugar to alcohol to make beer and wine.
• Microbial growth is also responsible for spoilage of food.
• Bacteria that use alcohol and produce acetic acid spoil wine by turning it to vinegar (acetic acid).
Fermentation and Pasteurization
• Pasteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine. This application of a high heat for a short time is called pasteurization.
Fermentation and Pasteurization
Figure 1.4
• 1835: Agostino Bassi showed a silkworm disease was caused by a fungus.
• 1865: Pasteur believed that another silkworm disease was caused by a protozoan.
• 1840s: Ignaz Semmelwise advocated hand washing to prevent transmission of puerperal fever from one OB patient to another.
The Germ Theory of Disease
• 1860s: Joseph Lister used a chemical disinfectant to prevent surgical wound infections after looking at Pasteur’s work showing microbes are in the air, can spoil food, and cause animal diseases.
• 1876: Robert Koch provided proof that a bacterium causes anthrax and provided the experimental steps, Koch’s postulates, used to prove that a specific microbe causes a specific disease.
The Germ Theory of Disease
• Treatment with chemicals is chemotherapy.
• Chemotherapeutic agents used to treat infectious disease can be synthetic drugs or antibiotics.
• Antibiotics are chemicals produced by bacteria and fungi that inhibit or kill other microbes.
• Quinine from tree bark was long used to treat malaria.
• 1910: Paul Ehrlich developed a synthetic arsenic drug, salvarsan, to treat syphilis.
• 1930s: Sulfonamides were synthesized.
The Birth of Modern Chemotherapy
• 1928: Alexander Fleming discovered the first antibiotic.
• He observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus.
• 1940s: Penicillin was tested clinically and mass produced.
The Birth of Modern Chemotherapy
Similar to Figure 1.5
• Bacteriology is the study of bacteria.
• Mycology is the study of fungi.
• Parasitology is the study of protozoa and parasitic worms.
• Recent advances in genomics, the study of an organism’s genes, have provided new tools for classifying microorganisms.
• Proteomics is looking at the gene products
Modern Developments in Microbiology
Compound light microscopy
• Basic parts– Eyepieces (ocular lens)
– Base
– Condenser
– Iris diaphragm
– Objective lens
– Body tube
– Mechanical stage
– Adjustment knobs
Magnification
• Calculation:– Objective power x ocular power = total power
• Parafocial
• Paracentric
• Microscopic measurement– Micrometer? Why must we calibrate it?
Modern Developments in Microbiology
• Diagnostics
• Prevention
• Use as a tool
• Surveys and vigilance
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