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Microbes Midterm .docx

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Wilfrid Laurier University
Joel Weadge

MICROBES MIDTERM Cells and Microbes can be viewed as (unifying theme) 1) Biochemical catalysts - maintaining a thermodynamic energy flow far from equilibrium defines life - metabolism (chemical reactions), differentiation, motility, communication - enzymes: supply energy, precursors for biosynthesis, catalytic machinery 2) Genetic coding devices - ability to do this needs to be kept and transferred - reproduction, evolution - replicating DNA and forming RNA and proteins (transcription, translation) CHAPTER 1 MICROBIOLOGY: HISTORY AND APPLICATION Microbiology: the study of microorganisms Microorganisms: a microscopic organism consisting of a single cell, cell cluster or virus that carry out processes independently of other cells - viruses, bacteria, archaea, protozoa, algae, fungi Significance: - oldest life forms - ubiquitous (soil, water, air, food, etc.) - largest biomass - major biogeochemical processing - other life is dependent on these organisms - influence medicine, agriculture and industry ~Table 1.1 (distribution of microorganisms in and on earth)~ Scale of life - micro-range is 1um 100um - light microscope: 0.1um 1mm - electron microscope: 1nm 100um History - What people used to believe 1. unseen forces responsible for disease 2. seeing is believing 3. predominant theory was spontaneous generation o took about 200 years to over come theories Historical Roots of Microbiology Robert Hooke (England 1635-1703) - built microscope 30x, began mapping out veins on leaves o molds/fungi = 10um - cell theory: small compartments of life , revolutionized how people saw things - micrographia (1665) Antoni Van Leeuwenhoek (Netherlands 1632-1723) - able to see things 10-50 times smaller than Hooke - microscope smaller and more primitive - bacteria 1 um - wee animalcules bacteria (1676) - father of microbiology , discovered bacteria while studying water - Because of lack of experimental tools little progress was made in understanding bacteria until almost 150 years later when technology improved Edward Jenner (England 1749-1823) - brilliant observationist - small pox vaccination (1798) before people werent allowed to name children until they survived small pox o used cow pox to find vaccine - 1979 WHO declared smallpox eradicated - father of immunology Louis Pasteur (France 1822-1895) - recognized significance of iosmers which contributer to discovery of fermentation (beer, yeast) - downfall of spontaneous generation o heat experiments o developed swan neck flask allowing flask to be open to air o foods would putrefy from exposure to air, those that didnt were sterile - sterilization: killing all bacteria in objects, contributed to creation of vaccines for all things (bacteria - anthrax, virus - rabies, cholera) - importance of aseptic technique: keeping things as sterile as possible - Ignaz Semmelweis (Vienna 1846) - physicians assistant - childbed fever epidemic -physicians not washing hands b/t patients - cadaver poisoning - led to germ theory Robert Koch (Germany 1843-1910) - Nobel prize 1905 - link b/t microbes and disease (germ theory) - causative agents of anthrax (endospore-forming bacteria) and tuberculosis (blue rod cells in tubercular tissues via staining) - improved pure culture techniques - postulates (1890) 1) suspected pathogen must be present in all cases of the disease and absent from healthy animals 2) suspected pathogen must be grown in pure culture 3) cells from pure culture of suspected pathogen must cause disease in a healthy animal 4) suspected pathogen must be re-isolated and shown to be same as original o offered a meaning for cause and affect of disease - pure cultural microbiology: pathogen must be isolated and grown away from other microorganisms Martinus Beijerinick (Holland 1852-1931) - enrichment techniques: microorganisms isolated from natural samples using highly selective techniques of adjusting nutritional incubation o isolated many pure cultures out of soils and aquatic environments - metabolic diversity - described the 1 virus (TMV) - begins of virology Sergei Winogradsky (Russia 1856-1953) - nutrient cycling nitrogen/sulfur o first isolation of nitrogen fixing bacteria - chemolithotrophy: oxidation of inorganic compounds to yield energy - microbial communities Modern Microbiology Applications - research is heading towards defining minimalist genome: minimal complement of genes necessary for a living cell which would lead to defining prerequisites for life 1) Agricultural - plant cell manipulation - biological control (insecticides) - fermentation - nitrogen cycle nodule formation in legumes - plant pathogens - plant disease resistance natural and engineered - biodegradation/bioremediation - methane production 2) Environmental - aquatic systems - soil - airborne transmission air quality - low-nutrient environments - extremophiles - biodegradation, bioremediation and biodeterioration
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