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EDUCATION

EDUCATION. “ The purpose of education is to replace an empty mind with an open one.”. Bacteriology. 1 st observed by Leeuwenhoek – 1676 with single lens microscope. Definition - Bacteria. Single-celled microorganisms with a variety of shapes (spheres, rods, spirals)

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EDUCATION

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  1. EDUCATION “ The purpose of education is to replace an empty mind with an open one.”

  2. Bacteriology • 1st observed by Leeuwenhoek – 1676 with single lens microscope

  3. Definition - Bacteria • Single-celled microorganisms with a variety of shapes (spheres, rods, spirals) • a.k.a. Prokaryotes b/c they do not contain a nucleus (membrane bound organelle) • Genetic material contained in a single circular chromosome in the cytoplasm of the cell (nucleoid)

  4. Prokaryotic • Prokaryotic • Fewer organelle & smaller than Euk. • Cell wall • +/- capsule • Cell/ plasma membrane • Nucleoid • Cytoplasm • Ribosomes • +/-: pili, plasmids, flagellum • Few have endospore • Eukaryotic • Cell / plasma membrane • Nucleus • Nucleolus • Cytoplasm • Mitochondria • Golgi apparatus • Endoplasmic reticulum • Ribosomes • Vacuoles • Lysosomes

  5. Bacteriology • Grow in kinds of environments, extremes • Without bacteria life as we know it would cease to exist! BACTERIA RULE THE WORLD

  6. Bacteriology • Bacterial cells outnumber the other cells in our bodies by 10:1! • Majority harmless or beneficial • Digestive tracts of people and animals (ex: ruminants) Few cause infectious disease • Most common – respiratory diseases

  7. Bacteriology – Morphology • Wide variety • Spherical – cocci/coccus • Rod – bacilli/bacillus • Single cells, pairs, chains, clusters • Elongated to form filaments

  8. Bacteria

  9. Bacteriology – Cellular Structure • Cell membrane • Barrier to hold nutrients, proteins and other components of cytoplasm within cell • No membrane-bound organelles – few intracellular structures • No nucleus, mitochondria, chloroplasts, golgi apparatus and endoplasmic reticulum • Genetic material – single circular chromosome • In nucleoid in cytoplasm

  10. FEW BACTERIA HAVE ABILITY TO PRODUCE ENDOSPORES Persists in variable environment Not membrane bound Hairlike protein extensions Attach/communicate with Other cells Smaller than Eukaryotic Mobility Barrier against phagocytosis DNA outside chromosome Replicate independently Pass info via pilus

  11. Bacteriology • Treat infections with antibiotics • Also used for agricultural processes • Industrial processes • Waste treatment • Cheese and yogurt production • Manufacture of antibiotics and other chemicals

  12. Bacteriology

  13. Bacteriology – Extracellular Structures • Cell wall – around cell membrane • Essential to survival of many bacteria • Penicillin kills by inhibiting a step in synthesis of cell wall • 2 types • Gram positive – thick cell wall with many layers • Gram negative – thin cell wall • Based on reaction to Gram stain • Differences in antibiotic susceptibility

  14. Gram Staining • The bacterial kingdom is subdivided into main categories by a process called Gram Staining (named after Hans Christian Gram, a Danish bacteriologist). The process is a stain that illustrates the composition of the cell wall.

  15. The gram stain consists of these steps. • Crystal violet - stains both gram negative and positive bacteriaGram's iodine - fixes the stain in gram positive bacteriaEthanol or acetone - washes the stain from gram negative bacteriaSafranin - counterstain, will re-stain gram negative bacteria while not interfering with the previous stain in gram positive bacteria

  16. Gram stain Procedure Staphlylococcus sp. Streptococcus sp. Salmonella sp. Proteus sp.

  17. Bacteriology – Extracellular Structures • Glycocalyx (a network of polysaccharides) • Surrounds the cell wall • Varies in structural complexity • Disorganized extra-cellular polymer = slime layer • Highly structured = capsule • Protect from engulfment by macrophages • Act as antigens • Cell recognition • Allows attachment to inert surfaces (teeth, rocks, etc)

  18. Bacteriology – Endospores • Highly resistant, dormant structures • Consist of central core of cytoplasm containing DNA and ribosomes surrounded by cortex layer • Protected by impermeable and rigid coat • Certain genera of Gram-positive bacteria • Bacillus • Clostridium

  19. Bacteriology – Endospores • No detectable metabolism • Survive extreme physical and chemical stresses • UV light • Gamma radiation • Detergents/disinfectants • Heat • Pressure • Drying

  20. Bacteriology – Endospores • Survive millions of years • Survive exposures to vacuum/radiation in space • Can cause disease • Inhalation of Bacillus anthracis endospores • Contamination of deep puncture wounds with Clostridium tetani endospores => tetanus

  21. Anthrax

  22. Tetanus

  23. Bacteriology – Pathogens • Definition – bacteria or other agent that forms a parasitic association with other organisms • Major cause of human and animal death and disease • Examples: tetanus, food-borne illness (Salmonella, Campylobacteria), leprosy, Tuberculosis (TB) • Important in agriculture • Johne’s disease, mastitis, salmonella, anthrax

  24. Bacteriology – Pathogens • Each species has characteristic spectrum of interactions with hosts • Ex: Staph/Strep => skin infections, pneumonia, meningitis, sepsis • Can also be part of normal flora w/o causing any disease

  25. Bacteriology – Pathogens • Some organisms always cause disease • Ex :Rickettsia – gram (-) obligate intracellular parasites • Ehrlichia • Rickettsia rickettsii (RMSF) • Chlamydia – obligate intracellular parasite • Pneumonia • Urinary tract infections

  26. Bacteriology – Pathogens • Opportunistic • Primarily in immune suppressed hosts

  27. Bacteriology – Pathogens • Treatment • Antibiotics • Bacteriocidal • Bacteriostatic • Many types – each class inhibits a process in pathogen that is different from host

  28. Bacteriology – Pathogens • Prevention by using antiseptic measures • Sterilizing skin prior to needle puncture • Proper care of indwelling catheters • Sterilization of surgical and dental instruments • Disinfectants • Kill bacteria/other pathogens on surfaces • Ex: bleach; Roccal, chlorhexidine

  29. Bacteriology – Growth and Reproduction • Grow to fixed size • Asexual reproduction – binary fission • Can be rapid under optimal conditions • Double every 9.8 minutes • 2 identical clone daughter cells formed • Can also form more complex reproductive structures that facilitate dispersal

  30. Bacteriology – Growth and Reproduction • Cultured with solid or liquid media • Solid – agar plates – used to isolate pure cultures of a bacterial strain • Liquid • Measurement of growth • Large volumes needed • Selective media • Specific nutrients added or deficient or antibiotics added • Used to ID specific organisms

  31. Bacterial Reproduction

  32. http://www.sciencebuddies.org/science-fair-projects/project_ideas/MicroBio_Interpreting_Plates.shtmlhttp://www.sciencebuddies.org/science-fair-projects/project_ideas/MicroBio_Interpreting_Plates.shtml

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