Chapter 1Historical backgroundThe Compound microscope used by Robert Hooke. The objective lens was fitted at the end of an adjustable bellows (G), with illumination the specimenA drawing by Robert Hooke, which represents one of the first microscopic descriptions of microorganisms: a blue mold growing on the surface of leather; the round structures contain spores of the mold.PowerPoint PresentationDrawings of van Leewenhoek’ ‘Animacules’Slide 7Theory of spontaneous generationLouis Pasteur disproved the theory of spontaneous generation (1861)Pasteur’s Swan-Necked flask experimentOther important discoveries by Louis PasteurRobert Koch (1876)Slide 13Other important microbiologistsImportance of microogranismsVital activities of microorganismsNitrogen cycleSlide 18Flotation of gas vesiculate cyanobacteria from a bloom on a nutrient-rich lake, Lake Mendota, Madison, Wisconsin.Slide 20FoodSlide 22agricultureEnergy/ EnvironmentalSlide 25Biotehnology Genetic engineeringSlide 27Slide 28Medical microbiologyNew diseasesCauses of emergence of New diseasesCauses of Resurgence of old diseases.Death rates for the 10 leading causes of death in the United States: 2000. Infectious diseases were the leading causes of death in 1900, whereas today they are much less important. Microbial diseases are shown in red, nonmicrobial diseases in green. Data from the United States National Center for Health StatisticsSlide 34Five important characteristics of all cells areViruses, viroids and prionsVirusesSlide 38Slide 39Slide 40Comparaison between prokaryotic and eukaryotic cellSlide 42Chapter 1Humans and the microbial worldHistorical background•First microscope van Leeuwenhoek (1676)•Theory of spontaneous generation•Louis Pasteur (1857) disprove of the theory of spontaneous generation• Robert Koch (1876) germ theory of diseaseThe Compound microscope used by Robert Hooke. The objective lens was fitted at the end of an adjustable bellows (G), with illumination the specimenA drawing by Robert Hooke, which represents one of the first microscopic descriptions of microorganisms: a blue mold growing on the surface of leather; the round structures contain spores of the mold.van Leewenhoek’s microscopeDrawings of van Leewenhoek’ ‘Animacules’Theory of spontaneous generation•Tiny organisms could arise from non-living material.Louis Pasteur disproved the theory of spontaneous generation (1861) microbes are ubiquitous, reproducible, and not a consequence of new life arising spontaneously. • Air is filled with microorganismsexpt: filter air through cotton plug. Collected organisms looked like previously grown organisms in infusions. Drop cotton in sterile infusion it becomes cloudy. • To keep infusion sterile : Swan-Necked flaskPasteur’s Swan-Necked flaskexperimentOther important discoveries by Louis Pasteur•Fermentation is the result of microbial activity (1857) •Pasteurization 72oC (162oF) for 15 sec to prevent souring of wine and milk•Vaccine against Cholera, Rabies Anthrax.Robert Koch (1876) •Proved the Germ theory of disease: A specific disease was caused by a specific bacterium (Koch's postulates). Anthrax was a disease caused by Bacillus anthracis. Obtaining pure cultures was essential to prove theoryDetermined cause of Anthrax, Tuberculosis, CholeraGerm theory of diseaseA specific microorganism causes a specific disease. Kock’s postulates: 1- Microorganism must be present in every case of the disease2- Organism must be grown in pure culture from diseased hosts3- Produce the same disease from the pure cultureOther important microbiologists•Edward Jenner 1798: first to discover vaccine (cowpox to fight small pox)•Paul Erlich : (early 1900)First chemotherapy  salvarsan•Alexander Flemming (1929)  PenicillinImportance of microogranisms•Vital activities of microorganisms to the biosphere•Economic applications of microorganisms: food industry, agriculture, bioremediation, Useful products from bacteria, biotechnology.• Medical microbiologyVital activities of microorganisms•Major role in nutrient cycling of C, N, O, S, P…between organic and inorganic forms•Fix atmospheric nitrogen:Without bacteria fixing N2 into a chemical form that plants can use life would not exist.•Replenish O2 in the atmosphere.•Decompose organic matter including cellulose.Nitrogen cycleN c y c l e . e x e. Cyanobacteria were the first organisms responsible for oxygenating the atmosphere on Earth Cyanobacterium Anabaena. Heterocysts are the sole site of nitrogen fixation in heterocystous cyanobacteriaFlotation of gas vesiculate cyanobacteria from a bloom on a nutrient-rich lake, Lake Mendota, Madison, Wisconsin.Economic applications of microorganismsFood•Fermented products: Bread, wine, beer, yogurt, cheese… •Food additives: lysine, tryptophane, methionine, vitamins B12,C,D,E), flavors (diacetyl, acetaldehyde), organic acid, emulsifying agents (xanthan)•Enzymes: lipase used in cheese ripening, Amylase (used in brewing and baking), glucose isomerase used as high fructose corn syrop in soft drinksagriculture•Enhance plant production –N2 fixing bacteria especially Rhizobium, Frankia fix atmospheric N into NH3 (then NO3)•Composting•BiocontrolEnergy/ Environmental•Bioremediation Clean up toxic waste by Bacteria or fungi : organic and inorganic contaminants e.g. –PCP(pentachlorophenol used as wood preservative PCB polychlorinated biphenyl (lub.oil)–PAH polyaromatic hydrocarbons (plastisizers,–TCE tetrachloroethyane: solvent and degreasing agent–DDT and others pesticides–oil spills biodegraded by Pseudomonas spp•Sewage treatment•Biofuel•Microbial miningBiotehnology Genetic engineeringBacteriaused as factories for production of useful proteins and other products by introducing specific plant and animal genes into bacterial DNA. E.g..•Insulin, blood clotting factors, enzymes that dissolve blood clots •Potential vaccines against rabies, gonnorhea, leprosy, malaria and hepatitis B.•Genes that confer resistance to insect and viral diseases in plants•Gene therapy : inserting genetically engineered viruses into mammalian cells•Vaccine for hepatitis B :yeast cells are inserted with gene coding for protein coat isolated from Hepatitis B virus will produce protein coat. Yeast cells are cloned Protein coat is isolated from yeast, purified and used in vaccine to stimulate immune systemMedical microbiology•Past triumphs during the last