Bacterial morphology


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Bacterial morphology

  1. 1. G. Hariprasad M.Sc., M.Phil., Lecturer in Microbiology Department of Microbiology Thoothukudi Govt. Medical College Thoothukudi
  2. 2. Objectives <ul><li>The student should be able to: </li></ul><ul><li>Describe the typical bacterial cell based on size, shape and groupings. </li></ul><ul><li>Determine the medical importance of certain structural components in a bacterial cell. </li></ul><ul><li>To discuss the appropriate staining procedure to demonstrate bacterial morphology and special structures. </li></ul><ul><li>To perform the following staining techniques </li></ul><ul><ul><li>Gram staining </li></ul></ul><ul><ul><li>Acid-Fast staining </li></ul></ul>
  3. 3. Objectives <ul><li>Discuss the growth requirements of bacteria </li></ul><ul><li>Differentiate bacteria as to: </li></ul><ul><ul><li>source of carbon </li></ul></ul><ul><ul><li>source of energy </li></ul></ul><ul><ul><li>temperature requirement </li></ul></ul><ul><ul><li>oxygen requirement </li></ul></ul><ul><li>Discuss the bacterial growth curve </li></ul><ul><ul><li>lag phase </li></ul></ul><ul><ul><li>logarithmic phase </li></ul></ul><ul><ul><li>stationary phase </li></ul></ul><ul><ul><li>death phase </li></ul></ul>
  4. 4. SIZE OF BACTERIA <ul><li>Unit for measurement : Micron or micrometer,μm: 1μm=10-3mm </li></ul><ul><li>Size: </li></ul><ul><li>Varies with kinds of bacteria, and also related to their age and external environment. </li></ul><ul><li>Cocci : sphere, 1μm </li></ul><ul><li>Bacilli: rods , 0.5- 1 μm in width - 3 μm in length </li></ul><ul><li>Spiral bacteria: 1~3 μm in length and 0.3-0.6 μm in width </li></ul>
  5. 5. Microscope <ul><li>Beam of light </li></ul><ul><li>Beam of electron </li></ul>
  6. 6. Bacterial Morphology
  7. 7. Bacterial Cell <ul><li>Prokaryotes </li></ul><ul><ul><li>No true nucleus </li></ul></ul><ul><ul><li>No organelles </li></ul></ul><ul><li>Divide-binary fission </li></ul>
  8. 8. Parts of a Cell <ul><li>Cell envelope </li></ul><ul><ul><li>Cell wall- murein sacculus </li></ul></ul><ul><ul><li>Outer </li></ul></ul><ul><ul><li>Cell membrane-plasma membrane, cytoplasmic membrane </li></ul></ul><ul><ul><li>Capsule </li></ul></ul><ul><li>Cytoplasm </li></ul><ul><ul><li>Nucleiod </li></ul></ul><ul><ul><li>Ribosomes </li></ul></ul><ul><ul><li>Granules/inclusion bodies </li></ul></ul><ul><ul><li>Mesosomes </li></ul></ul>
  9. 9. Parts of a Cell <ul><ul><li>Spores </li></ul></ul><ul><ul><li>Plasmids </li></ul></ul><ul><li>Appendages </li></ul><ul><ul><li>Pili </li></ul></ul><ul><ul><li>Flagella </li></ul></ul>
  10. 11. Special components of Gram positive cell wall <ul><li>Teichoic acid </li></ul>SPA / M POTEIN
  11. 12. Special components of Gram negative cell wall
  12. 13. Cell wall <ul><li>Peptidoglycan </li></ul><ul><ul><li>N acetyl glucosamine & N acetyl Muramic acid </li></ul></ul><ul><ul><li>Protect the cell from osmotic changes </li></ul></ul><ul><ul><li>Rigidity </li></ul></ul><ul><ul><li>Multilayered in Gram positive </li></ul></ul><ul><ul><ul><li>Teichoic acid </li></ul></ul></ul><ul><ul><li>Mono to bi layered in Gram negative </li></ul></ul>
  13. 14. Chapter 4
  14. 15. Chapter 4
  15. 16. Chapter 4
  16. 17. Chapter 4
  17. 18. Chapter 4 GRAM NEGATIVE CELL WALL
  18. 19. Chapter 4
  19. 20. Chapter 4 LPS UNIT
  20. 21. . <ul><li>Outer membrane- gram negative only </li></ul><ul><ul><li>2 layers of lipids </li></ul></ul><ul><ul><li>Inner layer-phospholipids </li></ul></ul><ul><ul><li>Outer layer- Lipopolysaccharide </li></ul></ul><ul><ul><ul><li>3 regions </li></ul></ul></ul><ul><ul><ul><ul><li>Lipid A </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Core polysaccharide </li></ul></ul></ul></ul><ul><ul><ul><ul><li>O antigen </li></ul></ul></ul></ul>
  21. 23. <ul><li>Transmembrane proteins </li></ul><ul><ul><li>Porins </li></ul></ul><ul><ul><li>Integral proteins </li></ul></ul><ul><li>viability </li></ul>
  22. 24. Cytoplasmic Membrane <ul><li>Lipid bi layer </li></ul><ul><li>Selective permeability </li></ul><ul><li>Site of ATP production </li></ul><ul><li>Viability </li></ul>
  23. 25. Chapter 4
  24. 26. Chapter 4
  25. 27. Chapter 4
  26. 28. Cell membrane <ul><li>Site of biosynthesis of DNA, cell wall polymers and membrane lipids. Selective permeability and transport of solutes into cells </li></ul><ul><li>Electron transport and oxidative phosphorylation </li></ul><ul><li>Excretion of hydrolytic exoenzymes </li></ul>
  27. 29. CYTOPLASM <ul><li>Nucleiod </li></ul><ul><ul><li>Chromosomal DNA </li></ul></ul><ul><ul><li>Plasmids </li></ul></ul><ul><li>Inclusion bodies </li></ul><ul><ul><li>Storage of excess food and energy </li></ul></ul><ul><ul><ul><li>Metachromatic granules/ Babes ernst granules </li></ul></ul></ul><ul><ul><ul><li>Much granule </li></ul></ul></ul><ul><li>Spores </li></ul><ul><ul><li>Resist adverse condition </li></ul></ul><ul><ul><li>Ribosome – 70s-50s & 30s </li></ul></ul>
  28. 30. <ul><li>Capsule </li></ul><ul><ul><li>Polysaccharide </li></ul></ul><ul><ul><li>Antiphagocytic </li></ul></ul><ul><ul><li>antigenic </li></ul></ul><ul><ul><li>Virulence </li></ul></ul><ul><li>Pili </li></ul><ul><ul><li>Common pili- fimbriae </li></ul></ul><ul><ul><li>Sex pili- conjugation </li></ul></ul><ul><ul><li>antigenic </li></ul></ul>
  29. 31. Capsules and slime layers <ul><li>These are structures surrounding the outside of the cell envelope. They usually consist of polysaccharide; however, in certain bacilli they are composed of a polypeptide (polyglutamic acid). They are not essential to cell viability and some strains within a species will produce a capsule, whilst others do not. Capsules are often lost during in vitro culture. </li></ul><ul><li>Attachment </li></ul><ul><li>Protection from phagocytic engulfment. </li></ul><ul><li>Resistance to drying. </li></ul><ul><li>Depot for waste products. </li></ul><ul><li>Reservoir for certain nutrients. </li></ul><ul><li>protection </li></ul>
  30. 32. Pili <ul><li>Pili are hair-like projections of the cell , They are known to be receptors for certain bacterial viruses . Chemical nature is pilin </li></ul><ul><li>Classification and Function </li></ul><ul><li>Common pili or fimbriae : fine , rigid numerous, related to bacterial adhesion </li></ul><ul><li>Sex pili: longer and coarser, only 1-4, related to bacterial conjugation </li></ul>
  31. 33. Flagella <ul><li>Monotrichate/Amphitrichate/Lophotrichate/Peritrichate </li></ul><ul><li>Identification of Bacteria </li></ul><ul><li>Pathogenesis </li></ul><ul><li>Motility of bacteria </li></ul><ul><li>Some bacterial species are mobile and possess locomotory organelles - flagella. Flagella consist of a number of proteins including flagellin </li></ul><ul><li>The diameter of a flagellum is thin, 20 nm, and long with some having a length 10 times the diameter of cell. Due to their small diameter, flagella cannot be seen in the light microscope unless a special stain is applied. Bacteria can have one or more flagella arranged in clumps or spread all over the cell. </li></ul>
  32. 35. Flagella <ul><ul><li>Locomotion </li></ul></ul><ul><ul><li>antigenic </li></ul></ul>
  33. 36. Plasmid Plasmids are small , circular/line , extrachromosomal , double-stranded DNA molecules 。 They are capable of self-replication and contain genes that confer some properties , such as antibiotic resistance , virulence factors 。 Plasmids are not essential for cellular survival. Inclusions of Bacteria <ul><li>Inclusions are aggregates of various compounds that are normally involved in storing energy reserves or building blocks for the cell. Inclusions accumilate when a cell is grown in the presence of excess nutrients and they are often observed under laboratory conditions. </li></ul>granules
  34. 37. Nucleus <ul><li>Lacking nuclear membrane, absence of nucleoli, hence known as nucleic material or nucleoid, one to several per bacterium. </li></ul>
  35. 38. Endospores <ul><li>Resistant structure </li></ul><ul><ul><li>Heat, irradiation, cold </li></ul></ul><ul><ul><li>Boiling >1 hr still viable </li></ul></ul><ul><li>Takes time and energy to make spores </li></ul><ul><li>Location important in classification </li></ul><ul><ul><li>Central, Subterminal, Terminal </li></ul></ul><ul><li>Bacillus stearothermophilus -spores </li></ul><ul><ul><li>Used for quality control of heat sterilization equipment </li></ul></ul><ul><li>Bacillus anthracis - spores </li></ul><ul><ul><li>Used in biological warfare </li></ul></ul>Chapter 4
  36. 39. <ul><li>Dormant cell </li></ul><ul><li>Resistant to adverse conditions </li></ul><ul><li>- high temperatures </li></ul><ul><li>- organic solvents </li></ul><ul><li>Produced when starved </li></ul><ul><li>Contain calcium dipicolinate </li></ul><ul><li>DPA, D ipicolinic acid </li></ul><ul><li>Bacillus and Clostridium </li></ul><ul><li>Identification of Bacteria </li></ul><ul><li>Pathogenesis </li></ul><ul><li>Resistance </li></ul>
  38. 41. Chapter 4
  39. 42. Spore stain
  40. 43. Chapter 4
  41. 44. Mesosomes <ul><li>Mesosomes are specialized structures formed by convoluted inveigh-nations of cytoplasmic membrane, and divided into septal and lateral mesosome. </li></ul>
  42. 45. Metabolism <ul><li>Glucose catabolism </li></ul><ul><ul><li>EMP pathway </li></ul></ul><ul><ul><li>HMP </li></ul></ul><ul><ul><li>Etner duodoroff </li></ul></ul><ul><ul><li>TCA </li></ul></ul><ul><ul><li>ETC </li></ul></ul>
  43. 46. Fermentation <ul><ul><li>Homolactic fermentation </li></ul></ul><ul><ul><li>Heterolactic fermentation </li></ul></ul><ul><ul><li>Mixed acid fermentation </li></ul></ul>
  44. 47. Peptidoglycan synthesis
  45. 48. Physiology <ul><li>Nutritional requirement </li></ul><ul><ul><li>Carbon </li></ul></ul><ul><ul><ul><li>Lithotropic </li></ul></ul></ul><ul><ul><ul><li>Heterotrophic </li></ul></ul></ul><ul><ul><li>Nitrogen </li></ul></ul><ul><ul><li>Inorganic ions </li></ul></ul><ul><ul><li>Growth factors </li></ul></ul>
  46. 49. <ul><li>Physical Requirements </li></ul><ul><ul><li>Oxygen </li></ul></ul><ul><ul><ul><li>Superoxide dismutase </li></ul></ul></ul><ul><ul><ul><li>Catalase </li></ul></ul></ul><ul><li>Redox potential </li></ul><ul><li>Temperature </li></ul><ul><li>Ph </li></ul><ul><li>Osmotic condition </li></ul>
  47. 50. Spheroplast <ul><li>Forms in gram negative bacterium </li></ul>
  48. 51. Protoplast <ul><li>When lysozyme acts on Gram positive bacterium in a hypertonic solution, a protoplast is formed. </li></ul>
  49. 52. L-Forms <ul><li>L-form bacteria , also known as L-phase bacteria , L-phase variants , and cell wall-deficient (CWD) bacteria , are strains of bacteria that lack cell walls . [1] They were first isolated in 1935 by Emmy Klieneberger-Nobel , who named them &quot;L-forms&quot; after the Lister Institute in London where she was working [2] . </li></ul><ul><li>Two types of L-forms are distinguished: unstable L-forms , spheroplasts that are capable of dividing, but can revert to the original morphology, and stable L-forms , L-forms that are unable to revert to the original bacteria. </li></ul>
  50. 53. L FORMS
  51. 54. Hydrogen ion concentration
  52. 55. Bacterial growth cycle Lag Stationary death log No of viable cell time
  53. 56. <ul><li>Different Temps For Different Bacteria </li></ul><ul><li>Bacteria are grouped into three categories for optimum temperature-based growth: psychrophilic, mesophilic and thermophilic. Phileo in Greek means &quot;lover of.&quot; </li></ul><ul><li>Psychro - means low temperature. Psychrophilic bacteria are bacteria that grow best in low temperatures, such as 32 to 68 degrees F. </li></ul>
  54. 57. <ul><li>Examples of psychrophilic bacteria are basic soil bacteria like arthrobacter and psychrobacter. Arthrobacter is bacteria that helps neutralize the poisonous effects of some pesticides and nicotine, but psychrobacter is a cause of diseases like meningitis. </li></ul><ul><li>Meso - means &quot;moderate or middle.&quot; Mesophilic bacteria grow best in lukewarm to cool warm temperatures, or 77 to 113 degrees F. </li></ul>Different Temps For Different Bacteria – Contd.,
  55. 58. <ul><li>Thermophilic (thermo- means &quot;hot or heat&quot;) bacteria grow best in warm to hot temperatures, or 122 to 158 degrees F. </li></ul><ul><li>Examples of thermophilic bacteria are Bacillus flavothermus and Thermus aquaticus. Bacillus flavothermus is a spore-forming bacteria found in soils. Thermus aquaticus lives in hot water. It is an important bacteria that helps humans, plants and animals code, recode and reproduce DNA and RNA with precision. </li></ul><ul><li>Hyper means &quot;above.&quot; Hyperthermophilic bacteria will grow in very hot temperatures,- 122 degrees F– </li></ul><ul><li>Eg. Methanopyrus kandleri . </li></ul>Different Temps For Different Bacteria – Contd.,
  56. 59. Methanopyrus kandleri . (HYPERTHERMOPHILES)
  57. 60. <ul><li>This slideshow presentation is dedicated to my beloved Microbiology students </li></ul><ul><li>Thank you!!!!! </li></ul>