Main Themes in Microbiology

1. Main Themes in Microbiology Chapter 1

2. Humans are outnumbered • We have ~ 10 trillion cells in our body • We have 100 trillion foreign cells in/on our body!! • Tiny life forms are called microorganisms

3. What is a microorganism? • Could be… • Bacteria • Viruses • Protists • Protozoa and algae • Helminthes • Worms

4. What is microbiology? • Microbiology is a special area of biology that deals with tiny life forms not readily observed without magnification • Little guys are called: • Microorganisms • Microbes • Germs • Bugs

5. Can I do this for a living? • Geomicrobiologist- roles of microbes in the development of the earth’s crust

6. Marine microbiologist- study the oceans and its smallest inhabitants

7. Medical technologists- do tests to diagnose pathogenic microbes and their diseases

8. Nurse epidemiologists- analyze the occurrence of infectious diseases in hospitals

9. Astrobiologist- study the possibility of organisms in space

10. What do we focus on? • Genetics • Physiology • Appearance and survival • + and – characteristics • Environmental interaction • Host interaction • Uses in industry/agriculture

11. How long have these guys been around? • Practically forever! • Life on Earth started 3.5 billion years ago! • Prokaryotes came first • Then eukaryotes

13. Good or bad? • Both! • We’ve been using microorganisms for thousands of years!

14. Good Microbes • Yeast (microscopic fungi) = bread • Penicillin (moldy bread) = first aid

15. Biotechnology • Industry applications • Bacteria that can mine metals!

16. Genetic Engineering • Manipulates genetics to make new products and genetically modified organisms • Microbes can make drugs, hormones, and enzymes

18. Bioremediation • Fixing environmental problems with microorganisms

19. Bad Microbes • Pathogens- agents that cause disease • Over 2000 types of microbes that cause disease! • WHO says over 10 BILLION infections caused by microbes worldwide

20. Top Causes of Death in US

21. Bad microbes • Malaria • Actually a microbe (protist)

22. Malaria Prevention • Malaria nets cost $3-5 • 1/3 world population makes <$1/day • Which kid will sleep under the net tonight?

23. Gastric ulcers Heliobacter Cancer HPV Hepatitis viruses Diabetes coxsackievirus schizophrenia MS OCD Coronary artery disease Infertility Chlamydia The subtle side of microbes • Associated with 1st golden age of microbes over, 2nd just started

24. General Microbe Characteristics • TINY • Millimeters (mm), micrometers (µm), and nanometers (nm)

26. Prokaryotic or eukaryotic

27. 1 or a few cells

28. Free-living—live independently • Parasitic—microbes harbored and nourished inside host

29. Could be viruses • NOT ALIVE • NOT CELLS • Small amount of hereditary material wrapped up in a protein coating • “Obligate intracellular parasites”

30. * Viroids are smaller viruses

31. Adenovirus

32. Rhinovirus

33. Rhinovirus

34. Where does life come from? • Meat makes maggots

35. Shrooms spring from spruce

36. Rats from rotting refuse

37. Spontaneous Generation • The idea that life can arise from non-living matter • Aka abiogenesis • Competing theory—biogenesis • Life can only arise from living things of a similar nature

38. How can we prove or disprove this hypothesis? • Francesco Redi (1668) Hypothesis: Flies produce maggots on meat. Lay small eggs Set up a controlled experiment to test his hypothesis Found that by keeping flies away from meat, no maggots appear

39. Variables • Controlled variable: Jar, meat, location, temperature, time • Independent or Manipulative variable: Gauze covering the meat jars • Dependant (responding) variable: Whether maggots appear

40. John Needham – 1745 Hypothesis: spontaneous generation occurs under the right conditions • Boiled chicken broth and then sealed flask (thought heat would kill) • “Animalcules” swarmed after a few days • Therefore, he felt his hypothesis was right.

41. What was wrong with Needham’s hypothesis? Was it flawed? He assumed all the animalcules would be killed by heat

42. Louis Jablot • Hypothesis: even microscopic organisms must have parents • Boiled hay infusions very similar to Needham’s work • However, his uncovered WAS contaminated with growth

44. Lazzaro Spallanzani • 1776 • Attempted to disprove Needham’s work. • Took 4 flasks with broth in them • Left open – went cloudy • Sealed but not boiled – went cloudy • Boiled but left open – went cloudy • Sealed then boiled – stayed clear • Microbes were not found in this one but in all the other ones

45. What would have been Spallanzani’s hypothesis? Microorganisms form not from air but from other microorganisms. When broth was boiled and then sealed, no air could get in for organisms to reproduce.

46. What was wrong with what Spallanzani assumed? No air

47. Louis Pasteur - 1859 Tested Spallanzani’s work by using a curved neck flaskto prevent microbes from entering flask but would let air in Boiled broth of control and experimental flasks. Result: No growth in curved neck flask. Microbes collecting in bend

48. Pasteur’s broth in the curved necked flask stayed sterile for years until he tilted it and the airflow carried the microbes into the broth

49. Conclusion Contamination is due to microbes in the air. Spontaneous generation theory died here!!

50. John Tyndall Heated hay infusions for various times. Found 2 kinds of bacteria – 1. Those readily killed by heating 2. Heat resistant forms (endospores) **Between 1875 – 1918, most of the disease-causing bacteria were identified.