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The Science of Microbiology

The Science of Microbiology. Teaching Objectives. To define Microbiology To be familiar with history of Microbiology To introduce the following: The extent of the microbial world Microbial phylogenetic and metabolic diversity Interaction of microbes and hosts

sheila-zimmerman
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The Science of Microbiology

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  1. The Science of Microbiology . H.Gh.Safaei

  2. Teaching Objectives • To define Microbiology • To be familiar with history of Microbiology • To introduce the following: • The extent of the microbial world • Microbial phylogenetic and metabolic diversity • Interaction of microbes and hosts • Prokaryotic characteristic • Application of microbiology

  3. History of Microbiology • Antoni van Leeuwenhoek, DE (1673) • First observed live microorganisms (animalcules) • Schleiden and Schwann, DE • Formulated Cell Theory: cells are the fundamental units of life and carry out all the basic functions of living things • Pasteur, FR and Tyndall, UK (1861) • Finally disproved S.G.

  4. DEFINITIONS of Microbiology Microbiology is the study of microorganisms H.Gh.Safaei

  5. 5 x 1030 microbial cells exist on earth; cells constitute about 90% of the biomass of the entire biosphere. more than 90% of the cells in our bodies are microbes H.Gh.Safaei

  6. biologic diversity • Biochemistry, molecular biology, and genetics • The number of genes within a prokaryote may vary 468 in Mycoplasma genitalium 7825 in Streptomyces coelicolor, many of these genes must be dedicated to essential functions such as energy generation, macromolecular synthesis, and cellular replication H.Gh.Safaei

  7. Microorganisms of each cell type : 1. Eukaryotic - fungi, protozoa, algae, worms 2. Prokaryotic - bacteria 3. Viruses - neither – a cellular 4. number of transmissible plant diseases are caused by viroids 5.Prion, scrapie, a degenerative central nervous system disease of sheep H.Gh.Safaei

  8. ECOLOGICAL RELATIONSHIPS • SYMBIOSIS: neutral, antagonistic or synergistic relationship between two dissimilar organisms (SYMBIOTES, SYMBIONTS) living in close association with each other; • MUTUALISM (+/+): mutually beneficial relationship between two species • COMMENSALISM (+/0): relationship between two species in which one is benefited and the other is not affected, neither negatively nor positively • PARASITISM (+/-): relationship between two species in which one benefits (parasite) from the other (host); usually involves detriment to the host ,e.g. Mycoplasmas, chlamydiae and rickettsiae H.Gh.Safaei

  9. DIVISIONS OF MICROBIOLOGY • Organisms studied • 1. Bacteriology - study of bacteria • 2. Mycology - study of fungi • 3. Phycology - study of algae • 4. Protozoology - study of protozoa • 5. Virology - study of viruses • 6. Parasitology - study of parasites H.Gh.Safaei

  10. Prokaryote • small size, usually on the order of 1 micron in diameter, and the absence of a nuclear membrane • nucleoid and can be visualized by electron microscopy • The DNA of almost all bacteria is a circle with a length of about 1 mm H.Gh.Safaei

  11. Prokaryotic Communities • A useful survival strategy for specialists is to enter into consortia • Arrangements contribute to survival of the group as a whole • clone that may contain up to 108 cells • Genetic variability • Extracellular polysaccharides H.Gh.Safaei

  12. Health related 1. Etiology - identification of causative agent of disease 2. Epidemiology - study of spread , of disease 3. Immunology - study of immune system 4. Chemotherapy - treatment of disease with chemical compounds 5. Infection control - control of spread of infectious disease H.Gh.Safaei

  13. Processes, Functions 1. Microbial metabolism 2. Microbial genetics 3. Microbial ecology H.Gh.Safaei

  14. BENEFICIAL APPLICATIONS (WHY STUDY MICROBIOLOGY?) A. Causative agents of infectious diseases B. Normal flora 1. Beneficial metabolic functions 2. Antagonistic effect - prevents invasion pathogens, over growth of potential pathogens3. Normal flora vs. identification pathogen C. Environmental importance 1. Decomposers 2. Produce oxygen 3. Food chain 4. Sewage treatment H.Gh.Safaei

  15. Industrial importance • 1. Food industry • 2. Brewing industry • 3. Pharmaceutical industry • 4. Genetic engineering H.Gh.Safaei

  16. Research - genetics, metabolism • Simple cell structure • Rapid rate of growth • Inexpensive to culture H.Gh.Safaei

  17. ? H.Gh.Safaei

  18. H.Gh.Safaei

  19. BACTERIAL Taxonomy , Classification Cell Structure , Genetics, Metabolism H.Gh.Safaei

  20. Objective • To define the Taxonomy , Classification , • To be familiar with Classification of micro organism • To explain the cell structure of bacteria ( cell wall , cytoplasmic membrane, spore, flagella, capsule , gentics and metabolism ) H.Gh.Safaei

  21. DEFINITIONS • A. Taxonomy - study of classification. • B. Classification - arranging organisms into related groups H.Gh.Safaei

  22. Criteria used for bacterial classification & identification : 1. Morphology • a. Colony • b. Microscopic (cell) 2. Staining reactions (Gram stain - cell wall chemistry) 3. Physiological characteristics • a. Growth requirements - temperature, O2, pH, etc. • b. Nutritional requirements - biochemical activity (enzymes) • c. Structure of DNA • d. Antigenic structure - serological tests H.Gh.Safaei

  23. Bacterial cell structure • Cell wall • Cell membrane • Cytoplasm (Ribosome, Vacuoles, Mesosome ) • Nucleoid • Flagella • Pilli • Capsule • Spore H.Gh.Safaei

  24. Microorganisms of each cell type 1. Eukaryotic - fungi, protozoa, algae, Slime mold 2. Prokaryotic - bacteria 3. Viruses - neither – acellular H.Gh.Safaei

  25. Archaea (archaebacteria), • The Bacteria (eubacteria), H.Gh.Safaei

  26. PROKARYOTIC CELLS 1. No "true" nucleus - nucleoid. • a. No nuclear membrane. • b. No paired chromosomes. • c. No histones. • d. No nucleolus. 2. No organelles. 3. No cytoplasmic streaming. 4. Cell membrane contains no sterols. 5. Cell walls • a. All typical prokaryotic cells possess cell walls. • b. Composed of peptidoglycan (murein). 6. Division - binary fission. H.Gh.Safaei

  27. H.Gh.Safaei

  28. System of Classification 1. Based on following properties: • a. Type of cell - eukaryotic, prokaryotic • b. Structure - multicellular or unicellular • c. Mode of nutrition / metabolism - ingestion, absorption, photosynthesis • d. Structure DNA ( Sequence , % G+C) H.Gh.Safaei

  29. Characteristics of the organism : • a. Size - Micrococcus • b. Shape - Staphylococcus, Bacillus • c. Arrangement - Staphylococcus, Streptococcus • d. Color of colony - Micrococcus roseus • e. Habitat - Escherichia coli, Staphylococcus epidermidis • f. Nutritional requirements - Haemoplilusaegypticus • g. Disease - Neisseriameningitidis, N. gonorrhoeae, C. diphtheriae, V. cholerae • h. Researcher - Escherichia, Neisseria H.Gh.Safaei

  30. H.Gh.Safaei

  31. H.Gh.Safaei

  32. Cell Wall H.Gh.Safaei

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  35. Cell division H.Gh.Safaei

  36. Binary vision H.Gh.Safaei

  37. Binary Division • 1 to 2 to 4 to 8 to ? H.Gh.Safaei

  38. Bacterial growth • Bacterial growth is increase in cell numbers • Growth depends on temperature, pH, osmotic pressure, oxygen, and nutrients • Log phase cultures are most sensitive to growth inhibition H.Gh.Safaei

  39. The growth curve • Lag phase • exponential phase: balanced growth • Stationery phase • Death • Bacterial cell cycle and cell division H.Gh.Safaei

  40. H.Gh.Safaei

  41. Growth measurements: direct • Plate counts • detect viable organisms • Direct microscopic counts • detect total numbers H.Gh.Safaei

  42. Measuring Growth Turbidity Spectrophotometer Scale %Transmittance Optical Density or Absorbance Filtration 0.45 - 0.2 um sizes Grid Pattern on Filter Standards for Public Health 0 E.coli / 100 ml of water Also used for sterilization H.Gh.Safaei

  43. Requirements for bacterial growth • Definition of growth • New “state”: VBNC- viable but not culturable • Nutritional requirements: water, carbon, nitrogen, phosphorous, sulfur H.Gh.Safaei

  44. ????????? H.Gh.Safaei

  45. Bacterial growth • Physical requirements • pH • Temperature: Psychrophiles, Mesophiles- pathogens, Thermophiles • Osmotic pressure • Oxygen • Nutrients H.Gh.Safaei

  46. H.Gh.Safaei

  47. Temperature Problems • Thermophiles • Hot tubs-public • Heat Resistant Enzymes in PCR • Psychrophiles • Cold food (growth in transit) • Listeria grows in hot dogs H.Gh.Safaei

  48. Factors that Influence Growth • pH • Acidophiles: • Grow optimally between ~pH 0 and 5.5 • Neutrophiles • Growoptimally between pH 5.5 and 8 • Alkalophiles • Grow optimally between pH 8 – 11.5 H.Gh.Safaei

  49. Physical Factors: • Moisture • Oxygen • Aerobes and Anaerobes • Osmotic Pressure • Pseudomonas grows in distilled water • Jelly- Jams (high sugar) • Salt (high salt) H.Gh.Safaei

  50. Nutritional Factors • Carbon Source • Auto- or Hetero- • CO2 or Organic compounds • Nitrogen Source • NO3- ==> NO2 ==> NH3 to Amino Acids ==> Proteins • Sulfur • Phosphorus • Trace Elements • Fe, some required • Host Sideophores bind Fe H.Gh.Safaei

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