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Microbial overview i

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Microbial overview i

  1. 1. rstobgi@gmail.com
  2. 2. rstobgi@gmail.com Microorganisms are the most abundant organisms on earth, found everywhere; air, water, soil, rocks (live bacteria even found in rocks more than a mile below earth's surface) Billionsper gram of fertile soil
  3. 3. rstobgi@gmail.com •Microbes can grow at temperatures from < 0°C (the snow alga, Chlamydomas nivalis) to 110°C (Pyrolobus fumarii). •A microbe that can grow in water over 100°C. • The P. fumarii grows under the sea at hydrothermal vents where the water pressure is very high.
  4. 4. rstobgi@gmail.com Note the large amount of material being precipitated out of the super-heated water (about 300C) as it comes in contact with ocean water at the sea floor (4C).
  5. 5. rstobgi@gmail.com Steam (C) Water at atmospheric pressure 1.0 bar 98-100 2.4 bar 125 3.0 bar 134
  6. 6. rstobgi@gmail.com • Most of the organisms we will examine will grow at 20-50°C. • Microbes are also present in saturated salt lakes, in acid mine drainage that is below pH 1, • In environments devoid of oxygen, in soil, and on you!
  7. 7. rstobgi@gmail.com • Micro-organisms are microscopic in size. • The smallest body that can be seen with the naked eye is about 100 μm. • All medically related bacteria are smaller than this and a microscope is therefore necessary • When spread on solid media, bacteria (and fungi) form macroscopically visible structures contain at least 108 cells, known as colonies.
  8. 8. rstobgi@gmail.com •Where are microbes NOT found? Only inside tissues of organisms, kept at an area by defensive mechanisms. Even so, challenges common (cut finger, get infected transient bacteraemia).
  9. 9. rstobgi@gmail.com Micro-organisms may be classified in the following large biological groups: Classification
  10. 10. rstobgi@gmail.com • theBacteria, • theArchaea • theEukarya. All living forms are seen to fall within three domains of life: Archaea =
  11. 11. rstobgi@gmail.com • Prokaryotes • Peptidoglycan cell walls • Binary fission • For energy, use organic chemicals, inorganic chemicals, or photosynthesis
  12. 12. rstobgi@gmail.com • Prokaryotic • Lack peptidoglycan • Live in extreme environments Include: – Methanogens – Extreme halophiles – Extreme thermophiles
  13. 13. rstobgi@gmail.com • Eukaryotes • Chitin cell walls • Use organic chemicals for energy • Molds and mushrooms are multicellular consisting of masses of mycelia, which are composed of filaments called hyphae • Yeasts are unicellular
  14. 14. rstobgi@gmail.com • Eukaryotes • Absorb or ingest organic chemicals • May be motile via pseudopods, cilia, or flagella Trypanosoma Giardia
  15. 15. rstobgi@gmail.com • Eukaryotes • Cellulose cell walls • Use photosynthesis for energy • Produce molecular oxygen and organic compounds Diatoms
  16. 16. rstobgi@gmail.com • 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
  17. 17. rstobgi@gmail.com • Eukaryote • Multicellular animals • Parasitic flatworms and round worms are called helminths. • Microscopic stages in life cycles.
  18. 18. rstobgi@gmail.com Microbial characteristics
  19. 19. rstobgi@gmail.com In fact, it is estimated that we have not yet isolated more than 1% of all the bacterial species, and there are many medically important organisms among them 'as yet uncultivated' micro- organisms.
  20. 20. rstobgi@gmail.com
  21. 21. rstobgi@gmail.com –Various diagnostic test systems are used to detect specific bacteria in clinical systems, including, –reaction with antibodies in ELISA formats, –immunofluorescence and –Increasingly PCR-based technology.
  22. 22. rstobgi@gmail.com • Typing of bacterial isolates is necessary for epidemiological investigations in outbreaks and for surveillance, and a variety of phenotypic and genetic methods has evolved for the identification of strains.
  23. 23. rstobgi@gmail.com Bacteria 538 Fungi 317 worms 287 Viruses 208 Parasites 57
  24. 24. rstobgi@gmail.com archea Eubacteria Protozoan with alteration AnO2 O2
  25. 25. rstobgi@gmail.com Bacteria and Archaea are present in all environments that support life. Procaryotes have the usual nutritional requirements for growth of cells, but many of the ways that they utilize and transform their nutrients are unique. This bears directly on their habitat and their ecology.
  26. 26. rstobgi@gmail.com Early Earth was AnO2, Cyanobacteria build up of O2 in atmosphere from 0% to 20% around 2 billion years ago (BYA). Lithotrophic and fermentative modes of metabolism were the first to develop in early prokaryotes.
  27. 27. rstobgi@gmail.com 2O2 - + 2H+ SOD H2O2+O2 2H2O2 Catalase 2H2O +O2 SOD=Superoxide dismutase
  28. 28. rstobgi@gmail.com Neutrophiles ( 5 to 8) Acidophiles (below 5.5) Alkaliophiles (above 8.5)
  29. 29. rstobgi@gmail.com ENDEMIC ( disease present or usually prevalent in a population or geographic area at all times EPIDEMIC ( disease occuring suddenly in numbers clearly in access of normal expectancy PANDEMIC ( a widespread epidemic distributed or occuring widely throughout a region, country, continent, or globally
  30. 30. rstobgi@gmail.com Organism Time needed to consume body weight Human 180 Days Pig 20 Days Yeast 30 Minutes Lactobacillus 10 Minutes Micrococcus 3 Minutes
  31. 31. rstobgi@gmail.com • 1. The invisible world of microbes underlies and shapes what we call the "visible world". • 2. Microbes have extraordinary genetic and metabolic diversity. • 3. Microbial metabolism can create anaerobic environments, and anaerobic microbes can use these environments. • 4. Different microbes are adapted to survive and use an enormous range of environments, both inanimate and animate. • 5. Among all life forms on earth, microbes have the widest range of genetic and evolutionary diversity.
  32. 32. MICROBES & ECOLOGY • Many microbes (bacteria and fungi) are decompsers (saprotrophic) and break down organic matter. • Decomposers release nutrients form dead organisms and return them to the ecosystem. • These free nutrients are recycled & used by other organism for growth, repair, & continuation.
  33. 33. MICROBES & INDUSTRY • Microbes are used in many industrial products and processes. • Some examples are the development of medicines (e.g. antibiotics), the production of chemicals (alcohols, organic acids, acetone), the production of various enzymes, vitamins, hormones, steroids, and perfumes.
  34. 34. rstobgi@gmail.com • Microbes are widely used in food production. • Examples of microbial food products are: • Cheese, sour cream, yogurt, butter milk, vinegar, bread and soy sauce. • Typically involves bacteria and/or yeast.
  35. 35. rstobgi@gmail.com • One of major human problems: getting rid of microbes, or preventing their growth. • Practical problem for food, beverage, cosmetic, pharmaceuticals, other industries.
  36. 36. rstobgi@gmail.com Disease can come about in several overlapping ways 1. Some bacteria are entirely adapted to the pathogenic way of life in humans. They are never part of the normal flora but may cause subclinical infection, e.g. M . tuberculosis 2. Some bacteria which are part of the normal flora acquire extra virulence factors making them pathogenic, e.g. E. coli
  37. 37. rstobgi@gmail.com Disease can come about in several overlapping ways 3. Some bacteria which are part of the normal flora can cause disease if they gain access to deep tissues by trauma, surgery, e.g. S. epidermidis 4. In immunocompromised patients many free-living bacteria and components of the normal flora can cause disease, especially if introduced into deep tissues, e.g. Acinetobacter
  38. 38. rstobgi@rml-b.com Growth/Culture condition The majority of microbes persist attached to surfaces within a structured biofilm ecosystem and not as free floating organisms. Microbiol. Mol. Biol. Rev. 64:847-867 (2000)

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