Lecture 11. Memorize the names of the scientists, their discoveries, when and how these scientists made their discoveriesa. The discovery of microorganisms began with the creation of the first primitive microscopesi. Robert Hooke (1660’s)1. First compound microscopes2. First to describe eukaryotic microorganisms3. Describe fruiting structure on fungi4. Named the unit of living material “cell”ii. Antoni van Leewenhoek (1676)1. Simple microscopes with 300X magnification2. First to describe bacteria3. Bacteria of various shapes and motility in many environmentsb. Discoveries in Microbiologyi. Louis Parteur (1822-1895)1. Made many significant discoveries in microbiology2. Discovered that living organisms discriminate between optical isomers3. Discovered that alcoholic fermentation was a biologically mediated process (originally thought to be a purely chemical process)4. Disproved theory of spontaneous generation (1864)a. An early theory that living organisms arose from non-living matter5. Germ theory of disease to explain the transmission of puerperal fever6. Developed pasteurization and sterilization methods7. Developed vaccines for anthrax, fowl cholera, and rabies (1885)ii. Other early discoveries linked germs with diseases1. 1860’s Joseph Lister2. Observations:a. Phenol was used for many years to deodorize sewageb. Read Pasteur paper that suggested microorganisms were responsible for gangrenec. His own experiments showed that phenol solutions killed microorganisms3. Hypothesis:a. Treating surgical sites, instruments, and dressings with phenol solution would result in lower infection rates4. Outcomea. Infection rates plummeted during surgeriesc. Link between individual microbes and infectious diseases/ Othersi. Robert Koch (1843-1910) 1. Used semi-solid media to grow and isolate pure culutres2. Pioneering work on tuberculosisa. Identified Mycobacterium tuberculosis as causative agentb. Produced tuberculin (exract from Mycobacterium tuberculosis)i. Initially tested as a vaccineii. Now used in skin testing to identify turberculosis infectionsc. Identified Vibrio cholera and Bacillus anthracis2. Describe the experiment performed to disprove the theory of spontaneous generationa. Pasteur disproved this theory using the swan neck flask experimentb. First step: Air can come in, but dust cannoti. Nothing happened it was all the samec. Dust introduced with microbes and bacteriai. Broth spoilsd. Not air that spoils broth its particles in the air3. Memorize and order Koch’s postulatesa. The suspected pathogen must be present in all cases of the disease and absent form healthy animals. (lab tools: Microscopy staining)b. The suspected pathogen must be grown in pure culture (Lab tools: Lab cultures)c. Cells from a pure culture of the suspected pathogen must cause disease in a healthy animal (Lab tools: Experimental animals)d. The suspected pathogen must be reisolated and shown to be the same as the original. (Lab tools: Laboratory reisolation and culture)4. Predict limitations to the application of Koch’s postulatesa. 1: People can carry a pathogen without being sick, Ex. HIVb. 2: There are some pathogens that we can’t grow in on a plate in a pure cultures, and you cant grow a virus without cells.5. Explain what Ignaz Semmelweis discovered in 1840’sa. Managed two birthing clinics in Vienna hospitalb. Observations: i. Birth assisted by midwives had much lower blood infection (sepsis) rates than births assisted by physicians (who also did autopsies on infection victims)ii. Physician performing autopsy on a sepsis victim accidentally cut himself and got sepsisc. Hypothesis: i. Dirty, unsanitary conditions lead to spread of infections in physician’s unitd. Action: i. Instituted sanitary measures, hand washing, disinfectant usee. Outcome: i. Infection rates decreased greatly6. Explain chemolithotrophya. Energy from oxidizing compoundsb. Chemolithotropgic organisms obtain their carbon from CO2c. Important in biogeochemical cycles7. Recall the discoveries of Beijerinck and Winogradskya. Beijerincki. 1880’sii. Established central role of microbes in nitrogen cycleiii. Proposed concept of phytopathogenic virusesiv. Developed enrichment culture technique to isolate metabolically diverse bacteriab. Winogradskyi. 1880s-1890sii. Autotrophic bacteria (use CO2 as sole carbon source)iii. Chemolithotrophy (energy from oxidizing inorganic compounds)iv. Chemolithotrophic organisms obtain their carbon from CO2v. Importance of chemolithotrophy in biogeochemical
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