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

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

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

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

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

6. 6 CLASSIFICATION ª Microbes « organisms smaller than the eye can detect © bacteria © fungi © protists © virus

7. 7 CELL TYPES ª Prokaryotes ª Eukaryotes ª Viruses

8. 8 PROKARYOTES ª Monera « bacteria « 1 micron diameter

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

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

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

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

13. PROKARYOTES VS EUKARYOTES

14. 14 CELL CHARACTERISTICS

15. 15 CELL CHARACTERISTICS

16. 16 CELL CHARACTERISTICS

17. 17 CELL CHARACTERISTICS

18. 18 CELL CHARACTERISTICS

19. 19 CELL CHARACTERISTICS

20. 20 CELL CHARACTERISTICS

21. 21 CELL CHARACTERISTICS

22. BACTERIAL SHAPE

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

24. 24 BACILLUS ª 1) Bacillus « Rod shape © Diplobacilli ¨ Two bacilli together © Streptobacilli ¨ Chains of bacilli © Vibrios ¨ curved rods

25. 25 BACILLUS ª Escherichia coli

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

27. 27 COCCI ª 3) Cocci « spherical shaped © diplococci ¨ remain in pairs © streptococci ¨ chains © staphylococci ¨ clusters

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

29. BACTERIAL CELL WALL

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

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

32. 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. 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. 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. 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. 36 CELL WALL ª cell walls of all bacteria are not identical ª cell wall composition is one of the most important factors in bacterial species analysis and differentiation ª clinically « contributes to ability to cause disease « site of action of antibiotics ª There are two major types of walls: « Gram-positive « Gram-negative

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

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

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

40. 40 GRAM POSITIVE

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

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

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

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

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

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

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

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

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

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

51. 51 CAPSULE

52. 52 SLIME LAYER ª Slime layer « disorganized and loosely attached to the cell wall © Staphylococcus mutans ¨ causes dental caries

53. 53 MOVEMENT ª Flagellum « Made of the protein flagellin « rotation is for swimming towards an attractant « water is as viscous as syrup for a bacteria « able to move 50 microns/sec © 100X bacterial body length/sec © fish able to swim only 10X body length/sec

54. 54 MOVEMENT ª Axial Filaments « found in Spirochetes « similar to flagella « attached throughout the body length

55. 55 PILI ª made of the protein pilin ª virulence factors ª project from the cell surface ª Conjugation Pili « for the transfer of extrachromosomal DNA between donor and recipient

56. 56 FIMBRIAE ª used for attachment to surfaces ª more numerous than pili

57. 57 CYTOPLASMIC STRUCTURES ª Nucleoid « area of concentrated DNA « no nuclear membrane « The DNA is single circular « double stranded without proteins

58. 58 CYTOPLASMIC STRUCTURES ª Ribosomes « cytoplasmic, not attached to organelles ª Plasmids « Extrachromosomal loops of DNA © some code for drug resistance © toxins

59. 59 TYPICAL BACTERIA

60. 60 ENDOSPORES ª Metabolically inactive ª may produce endospores under environmental stress « lack of water « lack of nutrients « severe temperature changes © Clostridium © Bacillus

61. 61 ENDOSPORES ª Spores can be dormant for many years ª can survive « extreme heat « desiccation « radiation « toxic chemicals

62. 62 ENDOSPORES ª when conditions become favorable they revert to an active state ª Spore germination is activated by heat in the presence of moistures

63. END CELL BIOLOGY OF BACTERIA