GEN MICROBIOLOGY BIOL 2051
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This 5 page Class Notes was uploaded by Charles Kohler on Tuesday October 13, 2015. The Class Notes belongs to BIOL 2051 at Louisiana State University taught by K. Sullivan in Fall. Since its upload, it has received 15 views. For similar materials see /class/222793/biol-2051-louisiana-state-university in Biological Sciences at Louisiana State University.
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Date Created: 10/13/15
Microbiology 0 The study of organisms too small to be seen with the naked eye 0 Importance 0 Medicine I Making antibiotics I Controlling disease 0 Agriculture I Nitrogenfixing bacteria I Genetically engineered crops 0 Food Industry I Beer wine bread yogurt pickles chocolate 0 Genetic engineering I lnsulin growth hormone vitamins I Crops resistant to pests heat pesticides herbicides etc 0 Keep us alive I Recycle nutrients I Produce vitamins I Degrade organic matter 0 Cause diseases most microbes are not pathogenic I HIV colds STDs food poisoning flu o Microbiologists study 0 Bacteria Viruses Protozoans Fungi Algae Diatoms Etc Chapter 1 Microbial Life Origin and Discovery What Is a Microbe 6 major groups studied by microbiologists 7 Prokaryotes no internal structure no membrane bound structures 1 Bacteria 2 Archaea 7 Eukaryotes 1 Algae 2 Protozoa 3 Fungi 7 Viruses Microbes Shape Human History Microbes affect food availability Destroy crops but preserve food Microbial diseases change history Black plague in Europe 7 Smallpox in Americas More soldiers have died from infection than battle wounds 7 TB AIDS 12 Discovew of Microbes I Light microscope invented in 1600s I Mid1600s R rt Hooke observes small eukawotes I 1st to use term quotcellsquot Antonivan Leeuwenhoek16 6 I Built simple microscopes Described quotwee animalcules Published first drawings of bacteria prokawotes Microbes Are Living Orga 39 M obes arise only from other microbes 7 No spontaneous generation 1861 Pasteur shows that microbes do not grow in liquid un m u A that 7 til introduced from outside II Men g om nonliving matter He disproved this using broth in swannecked flasks Pasteurflask Sterilized broth by boiling bent necks of flasks so that air could enter but microbes would be caught in neck Oventniiv summing dusxlndmluohu mm medlum I edtoquot 39 memuuuuu quot39 Lu 7 I Pasteu rization use of moderate heat to reduce the number of microorganisms in foods milk wine oysters m theow of disease I Vaccines for anthrax fowl cholera rabies Germ Theow of Disease rvations 7 Germs can infect and grow on food Hypothesis Can germs infect and grow on people That is do germs cause disease I Hypothesis is testable 7 A re germs found in infected tissue Can transmission of germs cause disease Koch39s Postulates I P ides means of testing hypothesis I Does this germ cause that disease Organism must meet 4 criteria 1 The microbe is found in all cases of disease but absent from healthy individuals 2 The microbe is isolated from the diseased host and g own in pure culture 3 When the microbe is introduced into a healthy susceptible host the same disease occurs 4 The same strain of microbe is obtained from the newly diseased host Joseph Lister 64 British surgeon found that survival rate of surgical patients increased if surgeons washed hands sterilized instruments and used disinfectants carbolic acidphenol during surgew gnas Semmelweis mid 1 I Puerperalfeverchildbedfever Medical students carried cadaver particles from autopsy room to delivew room Ca used by Streptococcus I Had med students wash hands in chlorinated lime water reduced mortality from 18 to 1 Edward Jenner1778 0 found that milkmaids exposed to cowpox were immune to smallpox o Vaccinated people including his son with cowpox they were resistant to smallpox 0 Lady Montagu Brought idea of smallpox vaccine back from Turkey to Europe 0 cartoon showing public reaction to cowpox vaccine Paul Ehrlich early 1900 s Idea for quotmagic bullet that would kill pathogens but not harm humans found arsenic compounds used to destroy trypanosomes Discovered Salvarsan to treat syphilis Used term quotchemotherapyquot using chemicals to kill pathogens without harming patient Arsenic turned out to be fairly toxic to humans Alexander Fleming 1929 o discovered antimicrobial effects of penicillin 3 produced by Penicilium notatum fungus on Staphylococcus o 1945 Nobel Prize in Medicine Fleming for discovery Florey amp Chain for determining mode of action of penicillin and developing method of mass producing the drug 0 1945 penicillin became available for general use Koch ampTuberculosis 1881 17 15 of all deaths caused by TB Thought it was contagious but had never seen organism Mycobacterium tuberculosis grows very slowly hard to stain due to lipid content Koch developed acidfast staining procedure patient enough to get pure culture 1905 Nobel Prize was awarded to Koch for his work on tuberculosis Koch amp solid culture media Potato slices 7 Streaked bacteria onto potatoes 7 Problem too much moisture many contaminants Beef broth solidified with gelatin 7 Problems Gelatin liquefies above 28 C Many microbes produce enzyme called gelatinase liquefies gelatin Agar 7 polysaccharide derived from red algae 7 1882 Fannie Hesse wife of Koch s coworker suggested agar She used it to make jelly 7 Solid until 100 C and most microbes cannot digest it Petri Dish Richard Petri Koch s assistant invented them in 1887 Before this they used a bell jar or a glass box Microbial Ecology Most microbes don t grow on typical medium N 01 of microbes in our biosphere can be cultured in the lab Many live in varied conditions 7 Anaerobic Bottom of swamp 7 High pressure Bottom of ocean 7 Hot or cold temperatures Below 0 C to 113 C 7 No organic carbon Use light for energy C02 for carbon Can culture some microbes in natural mud environment 7 Winogradsky column Layers grow different species reflecting different conditions 7 Can see variations in nature Yellowstone geyser runoff Colors reflect different species Different growth temperatures Microbes cycle most elements on earth 7 Nitrogen cycle Bacteria fix NZ to NH 7 Carbon cycle Photosynthetic microbes fix most carbon 7 Sulfur cycle 7 Phosphorus cycle The Microbial Family Tree Microbial species are difficult to classify 7 Difficult to distinguish by shape 7 Often reproduce asexually 7 Pass DNA to each other without reproduction Use biochemical properties to classify 7 Gram stain 7 Ability to metabolize different substrates Use DNA sequence to classify 7 Bacterial genomes are relatively small Several lineages exist in the domains Bacteria and Archaea huge diversity of cell morphologies and physiologies Phylogenetic tree of life 7 3 domains 7 Determined by rRNA sequencing Prokaryotic Microorganisms Bacteria most prokaryotes that we encounter soil bacteria diseasecausing bacteria etc 7 Ex Salmonella and Escherichia coli Archaea prokaryotes that live in extreme environments hot springs glaciers salt lakes 7 Ex Methanococcus and Halobacterium Archaea are not bacteria 7 Similar size shape 7 Very different biochemistry 7 Different membranes 7 Archaeal ribosomes similar to eukaryotic ribosomes 7 Many archaea live in harsh environments Eukaryotic Microorganisms includes fungi algae amp protozoa o Fungi nonphotosynthetic most have cells walls chitin 7 Ex Yeasts unicellular and molds multicellular hyphae 7 Saccharomyces yeast is used to make beer and bread 7 Penicilium mold produces penicillin o Algae 7 Photosynthetic contain chlorophyll have cell walls cellulose 7 Ex Diatoms amp seaweed o Protozoa 7 Unicellular motile no cells walls 7 Ex Amoeba Paramecium amp Giardia
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