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MICROBIOLOGY Cell Biology of Bacteria

MICROBIOLOGY Cell Biology of Bacteria. Northland Community & Technical College. Instructor Terry Wiseth. BACTERIAL FACTS. Scientists have named and described more than 4,000 species of bacteria

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MICROBIOLOGY Cell Biology of Bacteria

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  1. MICROBIOLOGYCell Biology of Bacteria Northland Community & Technical College Instructor Terry Wiseth

  2. BACTERIAL FACTS • Scientists have named and described more than 4,000 species of bacteria • New ones are discovered so rapidly, however, they estimate the number of unknown species in the millions • Almost every time scientists search among bacteria in a soil or water sample, they discover previously unknown species

  3. BACTERIAL FACTS • The overwhelming majority of bacteria are harmless to humans or animals • Bacteria get virus infections • Antibiotics and other bacteria-derived materials are the basis of a $50 billion annual market for biotechnology products • Oil spills are cleaned primarily by bacteria that feed on oil

  4. BACTERIAL FACTS • About 10 percent of human body weight and 50 percent of the content of the human colon is made up of bacteria (Escherichia coli) • each square centimeter of human skin hosts an average of 100,000 bacteria • Washing removes many, but they reproduce so quickly--doubling every 20 minutes--that the population is restored in hours

  5. BACTERIAL FACTS • So many bacteria live underground that their total weight has been estimated at 100 trillion tons • If these microbes were spread over Earth's land surface, they would make a layer five feet thick

  6. CLASSIFICATION • Microbes • organisms smaller than the eye can detect • bacteria • fungi • protists • virus

  7. CELL TYPES • Prokaryotes • Eukaryotes • Viruses

  8. PROKARYOTES • Monera • bacteria • 1 micron diameter

  9. EUKARYOTES • algae, protozoa and fungi • 5 - 100 microns

  10. VIRUSES • neither prokaryotes nor eukaryotes • informational parasites • each kingdom has its own associated viruses

  11. Virus 0.05 to 0.1 microns Bacteria 0.5 to 1.5 microns Red blood cell 5 microns Sperm 60 microns MICROBIAL SIZE

  12. MICROBIOLOGY • disease • agriculture • food and drink • chemical products • basic research • biotechnology

  13. PROKARYOTESVSEUKARYOTES

  14. CELL CHARACTERISTICS

  15. CELL CHARACTERISTICS

  16. CELL CHARACTERISTICS

  17. CELL CHARACTERISTICS

  18. CELL CHARACTERISTICS

  19. CELL CHARACTERISTICS

  20. CELL CHARACTERISTICS

  21. CELL CHARACTERISTICS

  22. BACTERIAL SHAPE

  23. BACTERIA SHAPE • range in size from 0.20 to 2.0 micrometers in diameter • 1) Bacillus • 2) Spiral • 3) Cocci

  24. BACILLUS • 1) Bacillus  • Rod shape • Diplobacilli  • Two bacilli together • Streptobacilli  • Chains of bacilli • Vibrios • curved rods

  25. BACILLUS • Escherichia coli

  26. SPIRAL • 2) Spiral • spirillia • Spiral, helical, corkscrew shape that is rigid • spirochete • the organism is flexible and undulating

  27. COCCI • 3) Cocci • spherical shaped • diplococci • remain in pairs • streptococci • chains • staphylococci • clusters

  28. COCCI • Moraxella catarrhallis • inhabitant of the upper respiratory tract, especially the nasal cavity • notice some are in the diploid state

  29. BACTERIALCELL WALL

  30. CELL MEMBRANE • phospholipid bilayer • integral and peripheral proteins embedded • maintains the selective permeability of the cell • has respiratory enzymes

  31. CELL WALL • cell wall surrounds the cell membrane • Structurally, the wall is necessary for • 1) maintain shape • 2) counter osmotic pressures • 3) attachment sites for bacteriophages • 4) platform for surface appendages

  32. CELL WALL • 1) Maintaining the cell's characteristic shape • the rigid wall compensates for the flexibility of the phospholipid membrane and keeps the cell from assuming a spherical shape

  33. CELL WALL • 2) Countering the effects of osmotic pressure • the strength of the wall is responsible for keeping the cell from bursting when the intracellular osmolarity is much greater than the extracellular osmolarity

  34. CELL WALL • 3) Providing attachment sites for bacteriophages • teichoic acids attached to the outer surface of the wall are like landing pads for viruses that infect bacteria

  35. CELL WALL • 4) Providing a rigid platform for surface appendages • flagella, fimbriae, and pili all emanate from the wall and extend beyond it

  36. CELL WALL • cell walls of all bacteria are not identical • cell wall composition is one of the most important factors in bacterial species analysis and differentiation • clinically • contributes to ability to cause disease • site of action of antibiotics • There are two major types of walls: • Gram-positive • Gram-negative

  37. GRAM POSITIVE • Has a thick peptidoglycan layer • 90% of the Gram-positive cell wall is comprised of peptidoglycan • two types of teichoic acids

  38. GRAM POSITIVE • 1) Lipoteichoic acid • on the surface, embedded in the peptidoglycan layer • linked to the cytoplasmic membrane

  39. GRAM POSITIVE • 2) Wall teichoic acid • on the surface • linked to only the peptidoglycan layer

  40. GRAM POSITIVE

  41. GRAM NEGATIVE • cell wall of Gram-negative bacteria is much thinner • comprised of only 20% peptidoglycan • have two unique regions which surround the outer plasma membrane: • periplasmic space • lipopolysaccharide layer

  42. GRAM NEGATIVE • a thin peptidoglycan layer • an outer membrane attached to the peptidoglycan layer by lipoproteins

  43. GRAM NEGATIVE • the outer membrane is made of protein, phospholipid and lipopolysaccharide • the lipid portion is embedded in the phospholipid • The lipid is toxic

  44. GRAM NEGATIVE • The cell wall has channels called Porins for the transport of low molecular weight substances

  45. GRAM NEGATIVE • periplasmic space • between the cytoplasmic membrane and the cell wall • hydrolytic enzymes • antibiotic inactivating enzymes • transport proteins

  46. GRAM NEGATIVE • Strong negative charge assists in: • evading phagocytosis • evade the complement system • provides increased barrier to: • antibiotics, lysozymes, detergents

  47. GRAM NEGATIVE • provides more attachment sites for: • virus • harmful substances • more susceptible to mechanical breakage • lipid A endotoxin is toxic to host

  48. CELL WALL • the cell wall is not a regulatory structure like the cell membrane • though it is porous, it is not selectively permeable and will let anything pass that can fit through its gaps

  49. EXTRACELLULAR MATRIX • attached to the cell wall • made of polysaccharide or polypeptide, or a combination of both • form a viscous layer • capsule • slime layer

  50. CAPSULE • Capsule • thick, structured and adheres strongly to the cell wall • Adhere to surfaces to form colonies • Antiphagocytic • Antigenic • Protect the organism from dehydration

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