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Bacteria, shapes arrangements, Characteristics, Classification, Nutrition, Reproduction, Growth curve, Metabolism, Cyanobacteria, Archaea, Actinomyces, Rickettsia, plant pathogenic Bacteria, Disease cycle

Bacteria, shapes arrangements, Characteristics, Classification, Nutrition, Reproduction, Growth curve, Metabolism, Cyanobacteria, Archaea, Actinomyces, Rickettsia, plant pathogenic Bacteria, Disease cycle


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  1. 1. Bacteria constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria A prokaryote is a unicellular organism that lacks a membrane- bound nucleus, mitochondria, or any other membrane-bound organelle Prokaryotes are divided into two domains, Archaea and Bacteria. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste and the deep biosphere of the earth's crust. Bacteria also live in symbiotic and parasitic relationships with plants and animals. Bacteria were first observed by the Dutch microscopist Antonie van Leeuwenhoek in 1676
  2. 2. Character Prokaryotes Eukaryotes Nucleus Absent Nuclear envelope and nucleolus Membrane- bound organelles Absent Present. Includes mitochondria, chloroplasts (plants), lysosomes Chromosome (DNA) Single coiled chromosome in cytoplasm ‘nucleoid’ region Multiple linear chromosomes with histone proteins Cell wall Eubacteria have a cell wall of peptidoglycan Archaea have cell walls of pseudomurein No cell wall in animal cells Plant cell walls = cellulose Fungal cell walls = chitin Mitotic division Absent Present Ribosomes 70S. Free in cytoplasm 80S. Both free in cytoplasm and attached to rough E.R. Flagella when present consist of protein flagellin consist of 9+2 arrangement of microtubules Mitochondria Absent Present Lysosomes Absent Present Golgi apparatus Absent Present Endoplasmic Reticulum Absent Present
  3. 3. Bacteria
  4. 4. Shapes of Bacteria • Coccus – Chain = Streptoccus – Cluster = Staphylococcus • Bacillus – Chain = Streptobacillus • Coccobacillus • Vibrio = curved • Spirillum • Spirochete • Square • Star Bacteria
  5. 5. Bacteria Shapes and Arrangements
  6. 6. Bacterial Structures • Chromosome • Flagella • Pili • Capsule • Plasma Membrane • Cytoplasm • Cell Wall • Lipopolysaccharides • Teichoic Acids • Inclusions • Spores Bacteria
  7. 7. Bacteria
  8. 8. Flagella • Motility - movement • Swarming occurs with some bacteria • Arrangement basis for classification – Monotrichous; 1 flagella – Lophotrichous; tuft at one end – Amphitrichous; both ends – Peritrichous; all around bacteria Bacteria
  9. 9. Pilli • Short protein appendages smaller than flagella • Adhere bacteria to surfaces – Antibodies to will block adherance • F-pilus; used in conjugation – Exchange of genetic information • Flotation; increase boyancy – Pellicle (scum on water), – More oxygen on surface Bacteria
  10. 10. Capsule or Slime Layer • Glycocalyx - Polysaccharide on external surface • Adhere bacteria to surface – S. mutans and enamel of teeth • Prevents Phagocytosis – Complement can’t penetrate sugars Bacteria
  11. 11. Cytoplasm • 80% Water {20% Salts-Proteins) – Osmotic Shock important • DNA is circular, Haploid – Advantages of 1N DNA over 2N DNA – More efficient; grows quicker – Mutations allow adaptation to environment quicker • Plasmids; extra circular DNA – Antibiotic Resistance • No organelles (Mitochondria, Golgi, etc.) Bacteria
  12. 12. Bacteria
  13. 13. Cell Membrane • Bilayer Phospholipid • Water can penetrate • Flexible • Not strong, ruptures easily – Osmotic Pressure created by cytoplasm Bacteria
  14. 14. Cell Wall • Peptido-glycan Polymer (amino acids + sugars) • Unique to bacteria • Sugars; NAG & NAM – N-acetylglucosamine – N-acetymuramic acid • D form of Amino acids used not L form – Hard to break down D form • Amino acids cross link NAG & NAM Bacteria
  15. 15. Chapter 4 Lipopolysaccharide (LPS) • Endotoxin or Pyrogen – Fever causing – Toxin nomenclature • Endo- part of bacteria • Exo- excreted into environment • Structure – Lipid A – Polysaccharide • O Antigen of E. coli, Salmonella • G- bacteria only – Alcohol/Acetone removes Bacteria
  16. 16. Bacteria
  17. 17. Bacteria
  18. 18. Bacteria
  19. 19. Endospores • Resistant structure – Heat, irradiation, cold – Boiling >1 hr still viable • Takes time and energy to make spores • Location important in classification – Central, Subterminal, Terminal • Bacillus stearothermophilus -spores – Used for quality control of heat sterilization equipment • Bacillus anthracis - spores – Used in biological warfare Bacteria
  20. 20. Bacteria
  21. 21. Bacteria
  22. 22. Bacteria
  23. 23. Bacteria Nutrition
  24. 24. Bacteria
  25. 25. Bacteria • Bacteria divide by binary fission • Alternative means – Budding – Conidiospores (filamentous bacteria) – Fragmentation
  26. 26. Bacteria
  27. 27. Bacteria
  28. 28. Generation Time • Time required for cell to divide/for population to double • Average for bacteria is 1-3 hours • E. coli generation time = 20 min – 20 generations (7 hours), 1 cell becomes 1 million cells!
  29. 29. Bacteria
  30. 30. Bacteria
  31. 31. • Commonly known as blue-green algae. • Autotrophic (Photosynthetic). • Contain chlorophyll a, phycocyanin (blue) and phycoerythrin (red). • They live in aquatic environments including oceans, ponds, lakes, tidal flats, and moist soil. • They exist mostly as colonies and filaments and sometimes as single cells. Cyanobacteria
  32. 32. Cell structure • The cell structure is very primitive. • Each cell is composed of two parts: a) cell wall b) protoplast. The cell wall is composed of 2 layers: The inner layer of which is thin and firm composed of peptidoglycan. The outer layer of the wall is thicker and gelatinous known as the sheath and mainly constituted of pectic compounds. Anabaena sp, Gloeocapsa sp, Microcystis sp Stigonema sp Chromoplast Central body Cell wall Cyanobacteria
  33. 33. Nostoc • Grows in water and on damp soils. • Unbranched filaments with barrel-like cells. • Certain enlarged cells appear at intervals, which are known as heterocysts . Its transparent and thick walls. • The whole filament is surrounded with gelatinous material. Reproduction in by fission. Prokaryotic cell. Lack chlorophyll b. Nostoc
  34. 34. • Nitrogen fixation • Can be used as food (Japan, Chad, and China) • Can pollute the water source (Lake). • High concentration may cause fish toxicity and other microorganism. Reproduction 1. Vegetative reproduction. 2. Asexual reproduction. B) By Akinetes.A) By fission. Importance of Cyanobacteria
  35. 35. • Prokaryotic • Lack peptidoglycan • Live in extreme environments • Include: – Methanogens – Extreme halophiles – Extreme thermophiles Archaea
  36. 36. Property Archaea Bacteria Eukarya Cell membrane Ether-linked lipids Ester-linked lipids Ester-linked lipids Cell wall Pseudopeptidoglycan, glycoprotein, or S-layer Peptidoglycan, S-layer, or no cell wall Various structures Gene structure Circular chromosomes, similar translation and transcription to Eukarya Circular chromosomes, unique translation and transcription Multiple, linear chromosomes, but translation and transcription similar to Archaea Internal cell structure No membrane-bound organelles (?[62]) or nucleus No membrane-bound organelles or nucleus Membrane-bound organelles and nucleus Metabolism[63] Various, including diazotrophy, with methanogenesis unique to Archaea Various, including photosynthesis, aerobic and anaerobic respiration, fermentation, diazotrophy, and autotrophy Photosynthesis, cellular respiration, and fermentation; no diazotrophy Reproduction Asexual reproduction, horizontal gene transfer Asexual reproduction, horizontal gene transfer Sexual and asexual reproduction Protein synthesis initiation Methionine Formylmethionine Methionine RNA polymerase Many One Many Toxin Sensitive to diphtheria toxin Resistant to diphtheria toxin Sensitive to diphtheria toxin Archaea
  37. 37. Nutritional types in archaeal metabolism Nutritional type Source of energy Source of carbon Examples Phototrophs Sunlight Organic compounds Halobacterium Lithotrophs Inorganic compounds Organic compounds or carbon fixation Ferroglobus, Methanobacteri a or Pyrolobus Organotrophs Organic compounds Organic compounds or carbon fixation Pyrococcus, Sulfolobus or Methanosarcin ales Archaea
  38. 38. Actinomyces is a genus of the Actinobacteria class of bacteria. They are all gram-positive. Actinomyces species are facultatively anaerobic (except A. meyeri and A. israelii both obligate anaerobe), and they grow best under anaerobic conditions. Actinomyces species may form endospores, and, while individual bacteria are rod-shaped, Actinomyces colonies form fungus-like branched networks of hyphae. Actinomyces
  39. 39. Actinomyces
  40. 40. Rickettsia
  41. 41. Rickettsia
  42. 42. Bacteria
  43. 43. Bacteria
  44. 44. Disease Location Comments Citrus canker Asia, Africa, Brazil, U.S. Caused eradication of millions of trees in Florida in 1910s and again in the 1980s and 1990s Fire blight of pome fruits North America, Europe Kills numerous trees annually Soft rot of vegetables Worldwide Huge losses of fleshy vegetables Bacterial leaf blight of rice Destructive in Japan and India spreading Bacterial wilt of banana Destructive in the Americas; spreading elsewhere Pierce’s disease of grape Deadly in southeast U.S.; spreading into California spreading Citrus variegation chlorosis Destructive in Brazil; spreading Citrus greening disease Severe in Asia; spreading Severe losses caused by Bacterial diseases
  45. 45. Symptoms of plant pathogenic Bacteria
  46. 46. Penetration and Invasion by Bacterial
  47. 47. Establishment of infection in a compatible reaction between a pathogen and its host plant
  48. 48. Disease cycle of a bacterial leaf blight Pseudomonas syringae pv. tabaci
  49. 49. Disease cycle of fire blight of pear and apple caused by Erwinia amylovora.
  50. 50. Disease cycle of crown gall caused by Agrobacterium tumefaciens
  51. 51. Disease cycle of common scab of potato caused by Streptomyces scabies
  52. 52. THANKS