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Microbial World

Microbial World. Dr. Kiran Afshan Department of Zoology. What is Microbiology?. Micro - too small to be seen with the naked eye Bio - life ology - study of Clinical Bacteriology: Bacteria that can cause infection in human beings. Organisms included in the study of Microbiology.

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Microbial World

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  1. Microbial World Dr. Kiran Afshan Department of Zoology

  2. What is Microbiology? • Micro - too small to be seen with the naked eye • Bio - life • ology - study of • Clinical Bacteriology: Bacteria that can cause infection in human beings

  3. Organisms included in the study of Microbiology • 1. Bacteria • 2. Protozoans • 3. Algae • 4. Parasites • 5. Yeasts and Molds • Fungi • 6. Viruses • Bacteriology • Protozoology • Phycology • Parasitology • Mycology • Virology Microorganisms - Microbes - Germs

  4. 5 Kingdoms of Living Organisms • 1. Animalia • 2. Plantae • 3. Fungi • 4. Protista • 5. Monera - Bacteria and Cyanobacteria • Eukaryotic vs. Prokaryotic

  5. 5 Characteristics of Life • 1. Cells • 2. Maintain structure by taking up chemicals and energy from the environment • 3. Respond to stimuli in the external environment • 4. Reproduce and pass on their organization to their offspring • 5. Evolve and adapt to the environment

  6. Taxonomic Classification • Kingdom • Phylum • Class • Order • Family • Genus • species • Man • Animalia • Chordata • Mammalia • Primate • Hominidae • Homo • Homo sapien

  7. Binomial System of Taxonomic Classification • Use only the Genus and species • Homo sapien • Felis domestica • Escherichia coli • Genus and species are either underlined or italicized • Genus is always capitilized • species is never capitilized

  8. Classification System • 3 Domains 1978 Carl Woese • 1. Bacteria • Unicellular prokaryotes with cell wall containing peptidoglycan • 2. Archaea • Unicellular prokaryotes with no peptodoglycan in cell wall • 3. Eukarya • Protista • Fungi • Plantae • Animalia

  9. Bacteria - what comes to mind? • Diseases • Infections • Epidemics • Food Spoilage • Only 1% of all known bacteria cause human diseases • About 4% of all known bacteria cause plant diseases • 95% of known bacteria are non-pathogens

  10. Microbes Benefit Humans • 1.Bacteria are primary decomposers - recycle nutrients back into the environment (sewage treatment plants) • 2. Microbes produce various food products • cheese, pickles, sauerkraut, green olives • yogurt, soy sauce, vinegar, bread • Beer, Wine, Alcohol

  11. 3. Microbes are used to produce Antibiotics • Penicillin • Mold • Penicillium notatum • 1928 Alexander Fleming

  12. 4. Bacteria synthesize chemicals that our body needs, but cannot synthesize • Example: E. coli • B vitamins - for metabolism • Vitamin K - blood clotting • Escherichia coli • Dr. Escherich • Colon (intestine)

  13. 5. Biochemistry and Metabolism • Very simple structure • rapid rate of reproduction • provides “instant” data

  14. 6. Microbial Antagonism • Our normal microbial flora prevents potential pathogens from gaining access to our body

  15. 7. Insect Pest Control • Using bacteria to control the growth of insects • Bacillus thuringiensis • Cotton Bollworms • bollworms • corn bollworms

  16. 8. Bioremediation • Using microbes to clean up pollutants and toxic wastes • Exxon Valdez - 1989 • 2 Genera • Pseudomonas sp. • Bacillus sp.

  17. 9. Recombinant DNA Technology Gene Therapy Genetic Engineering • Bacteria can be manipulated to produce enzymes and proteins they normally would not produce • Insulin • Human Growth Hormone • Interferon • Enzymes

  18. 10. Microbes form the basis of the food chain • Marine and fresh water microorganisms

  19. Microbes do benefit us, but they are also capable of causing many diseases

  20. Spontaneous Generation • Theory that life just “spontaneously” developed from non-living matter • Example: • toads, snakes and mice - moist soil • flies and maggots - manure and decaying flesh

  21. Experiments to disprove Spontaneous Generation • Francesco Redi 1668 • Rudolph Virchow 1858 • Theory of Biogenesis • Cells can only arise from preexisting cells • Louis Pasteur 1861

  22. Pasteur designed special “swan-necked flasks” with a boiled meat infusion Shape of flask allowed air in (vital force) but trapped dust particles which may contain microbes

  23. Spontaneous Generationliving organisms can develop from nonliving or decomposing matter

  24. Spontaneous Generation Controversy

  25. Spontaneous Generation Controversy

  26. Final blow to theory of spontaneous generation • John Tyndall (1820-1893) • demonstrated that dust carries microorganisms • showed that if dust was absent, nutrient broths remained sterile, even if directly exposed to air • also provided evidence for the existence of • exceptionally heat-resistant forms of bacteria

  27. Germ Theory of Disease • Hard for people to believe that diseases were caused by tiny invisible “wee animalcules” • Diseases, they thought, were caused by: • demons • witchcraft • bad luck • the wrath of God • curses • evil spirits

  28. Robert Koch - 1st to prove that bacteria actually caused diseases • 1876 • Microbial Etiology of Infectious Disease • etiology - the cause of a disease • Established “scientific rules” to show a cause and effect relationship between a microbe and a disease • Koch’s Postulates

  29. Figure 14.3 - Overview

  30. Anton van Leeuwenhoek 1674 - 1st person to actually see living microorganisms “wee animalcules”

  31. Exceptions to Koch’s Postulates • Microorganisms that are unable to be cultured on artificial media • (example: Treponema pallidum) • 2 or more organism work in synergy to cause a disease. • Symptoms and diseases can be causes by any one of several microbes.

  32. Exceptions to Koch’s Postulates • In exclusively human diseases, it is not morally acceptable to inoculate a deadly pathogen into a “human guinea pig” • HIV

  33. Koch established the Microbial Etiology of 3 important diseases of his day • 1. Cholera (fecal-oral disease) • Vibrio cholerae • 2. Tuberculosis (pulmonary infection) • Mycobacterium tuberculosis • 3. Anthrax (sheep and cattle) • Bacillus anthracis

  34. The Development of Techniques forStudying Microbial Pathogens • Koch - 1st to use Agar to solidify culture media • Koch’s work led to discovery or development of: – agar – petri dish – nutrient broth and nutrient agar – methods for isolating microorganisms

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