The Microbial World and You

1. The Microbial World and You

2. The Microbial World and You • Microorganisms • too small to be seen with unaided eye • “Germ” • rapidly growing cell

3. What are microbes? • Fungi (molds, yeasts) • mycology • Protozoa • parasitology • Microscopic algae • phycology

4. What do they do? • Decompose • organic waste • Producers in the ecosystem • by photosynthesis • Produce industrial chemicals • Ethanol and acetone • Produce fermented foods • vinegar, cheese, and bread • Produce manufacturing products • (e.g., cellulase) and treatment (e.g., insulin) • A few are pathogenic, • disease-causing Microbes everywhere on your body Microbes— Lactobacilliusacidophilus —make yogurt Others make beer and wine— Saccharaomycescereviceae

5. The better question might be, “what don’t they do?” • Allows humans to • Prevent food spoilage • Prevent disease occurrence • Led to aseptic techniques to prevent contamination in medicine and in microbiology laboratories

6. Did you know? • Bacteria causes body odor • Bacteria, tiny as they are, can get sick, too! • Under the right conditions a bacterium like Escherichia coli can grow from just one cell to 1 million cells in less than 7 hours! • How their size compares?

7. How are microbes named and classified? • Linnaeus established • system of scientific nomenclature. • Each organism has two names: • genus and specific epithet. • Are italicized or underlined. The genus is capitalized and the specific epithet is lower case. • Are “Latinized” and used worldwide. • May be descriptive or honor a scientist.

8. Scientific Names • Staphylococcus aureus • Describes the clustered arrangement of the cells (staphylo-) and the golden color of the colonies (aur-). • Escherichia coli • Honors the discoverer, Theodor Escherich, and describes the bacterium’s habitat–the large intestine or colon

9. Taxonomy

10. What is systematics? • Study of phylogenetic relationships • Phylogenetics = ________ • Taxonomy = __________ • Also a way of organizing/ classifying • Taxa (taxon—singular)

11. Look at the background! • Plant and Animal Kingdoms • Bacteria and fungi • put in the Plant Kingdom • Kingdom Protista proposed • for bacteria, protozoa, algae, and fungi • Prokaryote introduced for cells "without a nucleus“ • Prokaryote defined as cells in which nucleoplasm is not surrounded by a nuclear membrane • Kingdom Fungi • Kingdom Prokaryotae proposed • Two types of prokaryotic cells found

12. How are prokaryotes classified? • Use Bergey’s Manual of Systemic Bacteriology • Divides prokaryotes into (based on rRNA sequences) • Bacteria • Archaea

13. Who is Carl Woese? 1978: created current classification scheme • Three domains • Bacteria • Archaea • Eukarya • Protists • Fungi • Plants • Animals

14. What are the key differences between the three divisions?

15. What is the taxonomy of organisms? • Domain • Kingdom • Phylum • Class • Order • Family • Genus • Species

16. How are eukaryotes classified? • Endosymbiotic theory • Numerous kingdoms, including • Protista • Fungi • Plantae • Animalia

17. What about viruses—How are they classified? • Not included in three domains, which are _______ _______ and ______ • Why not? • Viral species: population of viruses with similar characteristics

18. B. anthracis B. japonicum How do I tell prokaryotes apart? • Really difficult • Morphology is very similar!

19. So how can we tell them apart? • Lab techniques such as • Staining • Gram positive vs. Gram negative

20. So how can we tell them apart? • Biochemical test • Different bacteria will grow on different types of media • Carbohydrates • Proteins • Serology • Slide agglutination test • Look for clumping of bacteria with antiserum • Serotypes are strains with different antigens • DNA fingerprinting • rRNA sequencing

21. A closer look at the microbes

22. What are bacteria? • Simple, single-celled • ubiquitous • Prokaryotes • DNA is not inside a membrane • Come in different shapes • Coccus (cocci, plural) • Bacillus (bacilli, plural) • Spiral (corkscrew, comma or curved) • Peptidoglycan cell wall • Binary fission • Some have flagella

23. What are archaea? • Also prokaryotes • Cells wall do not have peptidoglycan • Live in extreme conditions • Extreme halophiles • Hyperthermophiles • Methanogens • Not pathogenic Figure 4.5b

24. What are fungi? • Eukaryotes • Have a true nucleus • More closely related to __________ • wall of chitin • Uni- and multicellular • Includes • Molds • Mushrooms • Yeasts • Slime molds • Sexual and asexual reproduction Figure 1.1b

25. What are protozoa? • Eukaryotes • Absorb or ingest organic chemicals • May be motile via pseudopods, cilia, or flagella Figure 1.1c

26. What are algae? • Eukaryotes • Cellulose cell walls • Use photosynthesis for energy • Produce molecular oxygen and organic compounds Figure 1.1d

27. What are viruses? • Acellular • Consist of DNA or RNA core • Core is surrounded by a protein coat. • Coat may be enclosed in a lipid envelope. • Viruses are replicated only when they are in a living host cell. Figure 1.1e

28. What are multicellular animal parasites? • Eukaryote • Multicellular animals • Parasitic flatworms and round worms are called helminths. • Microscopic stages in life cycles. Figure 12.28a

29. Brief History of Microbiology

30. The First Observations • Ancestors of bacteria were • first life on Earth. • observed in 1673. • 1665, Robert Hooke reported • living things were composed of little boxes or cells. • 1858, Rudolf Virchow • cells arise from preexisting cells. • Cell theory: All living things are composed of cells and come from preexisting cells.

31. How did we discover microbes? • Before the microscope: • Spontaneous generation • “vital force” forms life. • Microscope • Van Leeuwenhoeke, 1670s • Louis Pasteur, 1861 • Showed microorganisms are in the air • Refutes spontaneous generation with biogenesis • Used curved flask

32. When was the golden age of microbiology? • 1857-1914 • Pasteurization • Developed after investigation of fermentation • Demonstration of aseptic technique • microbes are responsible for fermentation. • Fermentation • conversion of sugar to alcohol to make beer and wine. • Microbial growth • responsible for spoilage of food. • Pasteur demonstrated • spoilage bacteria killed by heat • Pasteruization • high heat for a short time.

33. The Germ Theory of Disease • Joseph Lister, 1860s used a chemical disinfectant to prevent surgical wound infections • Germ theory of disease • Robert Koch, 1876, Germany • Bacillus anthracis causes anthrax • provided the experimental steps • Vaccination • Edward Jenner, 1796 • Small pox and cow pox • Immunology

34. What about modern microbiology? • 1928: Alexander Fleming • first antibiotic. • Penicillium fungus made • antibiotic, penicillin, that killed S. aureus. • 1940s: Penicillin was tested clinically and mass produced. Figure 1.5

35. Some terms in microbiology • Bacteriology is the study of bacteria. • Mycology is the study of fungi. • Parasitology is the study of protozoa and parasitic worms. • Immunology is the study of immunity. Vaccines and interferons are being investigated to prevent and cure viral diseases • Virology is the study of viruses.

36. Some modern concepts • Bioremediation • degrade organic matter in sewage. • degrade or detoxify pollutants such as oil and mercury. • Biological Insecticides • Biotechnology • Genetic engineering UN 2.1

37. What is normal microbiota? • Normal microbiota prevent growth of pathogens. • Normal microbiota produce growth factors such as folic acid and vitamin K. • Resistance is the ability of the body to ward off disease. • Resistance factors include skin, stomach acid, and antimicrobial chemicals.

38. What are infectious diseases? • When a pathogen overcomes the host’s resistance, disease results. • Emerging infectious diseases (EID): New diseases and diseases increasing in incidence. • West Nile Virus • Bovine spongiform encephalopathy • Ebola hemorrhagic fever • Hantavirus • AIDS • Anthrax