chapter 1

chapter 1 - Chapter 1: History & Scope of Microbiology...

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Unformatted text preview: Chapter 1: History & Scope of Microbiology History Microbiology: Late 1600’s Microbiology: Science is not a profession, but more a hobby Science of the aristocratic class of 1676: van Leeuwenhoek: constructs first microscope; 300X magnification discovers ‘animalcules’ (bacteria and protozoa) discovers and describes several morphologies and Leeuwenhoek’s Microscope and Morphology Drawings Morphology Microbiology: Late 1600’s Microbiology: ? – 1688: Spontaneous generation is widely believed 1688: by scientists- living organisms arise from nonliving matter 1688: Redi disproves spontaneous generation of maggots from rotting disproves meat using 3 experimental containers meat A: open to the air- flies attracted, maggots appear A: B: covered with paper- flies not attracted, no maggots appear C: rotting meat covered with thin gauze- flies attracted, maggots C: appear on gauze but not on meat appear Microbiology: 1700 & 1800’s Microbiology: Belief in spontaneous generation comes back into Belief vogue, many work to disprove the theory vogue, 1760’s Spallazani: Sealed glass flasks and boiled contents 1760’s Spallazani: Concludes air either carries germs into the broth or air is required Concludes or for the growth of the germs for 1830’s Schwann: Flasks with boiled broths are left open to 1830’s air that had passed though a red-hot glass tube air Concludes air carries germs 1830’s Schroder: Flasks with boiled broths are stoppered 1830’s with sterilized cotton/wool with Concludes cotton/wool can keep germs out when used as stopper Concludes and that air carries germs that are obstructed by the cotton/wool and Microbiology: 1800’s cont. Microbiology: 1861 Pasteur: Interest in spontaneous came from necessity- Pasteur was a Interest wine-maker by trade Created a special swan-necked flask- air could flow Created through the flask but the path was long, and germs would settle out/be trapped in the curves settle Broth remained sterile for months, unless the flask was Broth tipped and air pushed the ‘settled’ germs down into the broth broth Finally spontaneous generation was solidly disproved Pasteur’s Swan-necked Flasks Pasteur’s Microbiology: 1800’s cont. Microbiology: 1862-1877: Many individuals re-attempt Pasteur’s swan-necked Many flask experiment and get varied results: Was Pasteur’s experiment was merely a fluke? experiment 1877 Tyndall: 1877 Notes that conditions of sterilization were different between all of the Notes individuals who tried to repeat Pasteur individuals Hypothesizes that some forms of germs may be more resistant to heat 1877 Cohn: 1877 Demonstrates the existence of a heat-resistant form of germs Demonstrates (endospores) (endospores) Both help create a unified concept of sterilization What Are Microorganisms? What Bacteria Viruses Fungi (yeasts and molds) Protozoa Algae Some multi-cellular organisms: Some flukes, tapeworms, etc. Microbial Diversity Microbial Life is classified into Life three Domains: Bacteria Archaea Eukarya Two Superdomains: Prokaryote: Prokaryote: Bacteria and Archaea Archaea Eukarya Eukaryotes: Eukaryotes: Prokaryotes vs. Eukaryotes Prokaryotes Prokaryotes: Eukaryotes: Exist as only unicellular Exist organisms organisms Lack membrane-bound Lack organelles organelles Condensed region of Condensed DNA is not bound by a membrane = nucleoid membrane Exist as unicellular or Exist multi-cellular organisms multi-cellular Have membrane-bound Have organelles organelles Condensed region of Condensed DNA is also bound by a membrane = nucleus membrane Domain Bacteria Bacteria Various morphologies: bacillus, coccus, Various spirochete, spirilla and vibrio spirochete, Size: 0.3 – 2.0 µm Size: Cell walls are rigid and contain peptidoglycan Cell peptidoglycan Reproduce or multiply by binary fission Motile by means of a flagellum/flagella Motile Domain Bacteria Bacteria Domain Archaea Archaea Morphologies and size are similar to bacteria Cell walls are rigid; contain Cell pseudopeptidoglycan pseudopeptidoglycan Reproduce or multiply by binary fission Motile by means of a flagellum/flagella Motile Live in extreme environments: hypersaline, Live hydrothermal vents, arctic oceans/ice hydrothermal Domain Archaea Archaea Domain Eukarya: Algae Eukarya Algae Single cells and multicellular (macroalgae) Contain pigments for Contain photosynthesis (autotrophic) (autotrophic) Aquatic Move by flagella, but Move different physical structure than found in prokaryotes prokaryotes Domain Eukarya: Fungi Eukarya Fungi Single cells and Single multicellular multicellular Saprophytic- live off Saprophyticdecaying material (heterotrophic) (heterotrophic) Mostly terrestrial, Mostly some aquatic some Mushrooms, molds, Mushrooms, yeasts yeasts Molds Yeast Domain Eukarya: Protozoa Eukarya Protozoa Single cells ranging Single from 2 to 20.0 µm Some are autotrophic, Some others are heterotrophs others Terrestrial and aquatic Some have CaCO3 or silica cytoskeletons silica Some are motile by Some flagella, cillia, or pseudopodia pseudopodia Amoeba Flagellates Binomial Nomenclature Binomial The The genus is always capitalized and species is always lower case lower are italicized (underlined if handwritten) Escherichia coli Escherichia coli Both Example: Example: There There Strain Strain can be many species in one genus designations may be used (i.e. E. coli JR124) to E. further differentiate species into subgroups further Microbes and Disease Microbes Pre-1800s: Diseases were thought to be caused Diseases by supernatural forces/imbalance in the 4 humours: humours: Blood, Phlegm, Yellow bile (choler), and Black Blood, bile (melancholy) bile 1830’s Bassi: Showed that fungi were the cause for disease in Showed silkworms and had nearly stopped silk production silkworms Microbes and Disease Microbes 1867 Lister: Founded aseptic technique practices Founded Believed that germs on skin and surgical Believed instruments were the cause of wound infections instruments Used phenol as the first antiseptic and heatsterilized instruments to effectively prevent sterilized wound infections wound Microbes and Disease Microbes 1876 Koch: Demonstrated the role of bacteria in causing disease and Demonstrated linked anthrax with Bacillus anthracis Bacillus Injected healthy mice with material from diseased ones Watched injected mice become infected Transferred infection thru a series of mice- each one Transferred became diseased became Removed spleen of infected mouse, placed it in beef broth Removed to grow bacteria to Injected bacterial solution into a healthy mouse and Injected observed the mouse become infected observed Microbes and Disease Microbes 1876 Koch: cont. Developed solid microbiological medias for Developed obtaining pure cultures of bacteria obtaining Used surfaces of freshly cut potatoes Used meat extract broths and added gelatin Fannie Hess- suggested to him that agar could be used Fannie in place of gelatin; more stable at high temps; most bacteria don’t use it bacteria Koch’s Postulates (Germ Theory) Koch’s 1. Microbe must be present in every case of disease 1. and absent in healthy organisms and 2. The suspected microbe must be isolated and grown 2. in pure culture in 3. The same disease must result when the isolated 3. organism is inoculated into a healthy host organism 4. The same microbe must be re-isolated from the 4. diseased host diseased Microbes and Disease Microbes 1880’s-1890’s Pasteur and colleagues: Developed a vaccine against the anthrax bacteria Developed and rabies virus using attenuation and Organism cannot cause disease Immunologic response of vaccinated individual occurs Individual develops immunity against the Individual bacterium/virus/toxin bacterium/virus/toxin Attenuation via: Successive passage through many hosts Successive Heat (42-43°C) or chemical treatment Other Microbial Roles Other Food Production Breadmaking- yeasts use sugars and produce CO2 Breadmakingto make bread rise to Alcoholic fermentation- yeasts and bacteria Alcoholic ferment sugars to produce ethanol in beer and wine wine Other fermentations- bacteria produce cheeses, Other sour cream, buttermilk, pickles, sauerkraut, sausages, etc. sausages, Other Microbial Roles Other Nutrient Cycling N2 fixing bacteria (Azotobacter, Rhizobium spp.) Rhizobium are important in agriculture for replacing nitrates in soils in Crop rotation efforts between legumes and nonlegumes keeps agricultural soils fertile without legumes adding chemical fertilizers adding Other Microbial Roles Other Industry Bacteria growth in bulk very quickly and Bacteria naturally synthesize useful chemicals like ethanol naturally GEMs can be by inserting human genes- causes GEMs bacteria to synthesize chemicals normally produced by humans: interferons, insulin, enzymes enzymes Other Microbial Roles Other Bioremediation GEMs as well as naturally occurring bacteria can GEMs be used to degrade toxic compounds like PCBs, DDT and petroleum spills DDT Passive vs. Active Learning Passive vs. Active Learning Passive Active Remembering: Retrieving, recognizing, and recalling relevant knowledge from long­term memory. Understanding: Constructing meaning from oral, written, and graphic messages through interpreting, exemplifying, classifying, summarizing, inferring, comparing, and explaining. Applying: Carrying out or using a procedure through executing, or implementing. Analyzing: Breaking material into constituent parts, determining how the parts relate to one another and to an overall structure or purpose through differentiating, organizing, and attributing. Evaluating: Making judgments based on criteria and standards through checking and critiquing. Creating: Putting elements together to form a coherent or functional whole; reorganizing elements into a new pattern or structure through generating, planning, or producing. Passive Learning Example Passive Learning Example Which of the following scientists was responsible for the development of modern microscopes? a) Lister b) Pasteur c) Leewenhoek d) Koch e) Spallazani Active Learning Example Active Learning Example Using the Domain taxonomic classification system, which specific group would a multicellular organism that possesses 18 chromosomes, has chitin in its cell walls, depends on heterotrophic uptake of organic carbon from the environment, and reproduces by both sexual and asexual reproduction methods belong to? a) Animalia c) Eukarya e) Bacteria b) Monera d) Archaea f) Fungi Critical Thinking MIBO Forums Critical Thinking MIBO Forums Earn up to 12 points extra credit Write, rate and comment on questions in a peer­evaluated forum Questions will also be rated as Good or Bad by professor and TA’s Use as a weekly study aid to evaluate your progress and preparation ...
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This note was uploaded on 03/24/2009 for the course MIBO 3500 taught by Professor Dustman during the Fall '09 term at UGA.

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