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CELL SHAPE Coccus - sphere - coccus Single Diplococcus – two

CELL SHAPE Coccus - sphere - coccus Single Diplococcus – two Clusters of cocci Streptococcus Bacillus- cylinder, rod Spiral shape- Rigid spirilla curved rods Flexible: spirochetes TYPICAL BACTERIAL CELL, BINARY FISSION

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CELL SHAPE Coccus - sphere - coccus Single Diplococcus – two

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  1. CELL SHAPE • Coccus - sphere - coccus Single • Diplococcus – two • Clusters of cocci • Streptococcus • Bacillus- cylinder, rod • Spiral shape- • Rigid • spirilla • curved rods • Flexible: spirochetes • TYPICAL BACTERIAL CELL, BINARY FISSION • CELL COMPONENTS • Cytoplasmic membrane phospholipid bilayerfluid mosaic modelsemi - permeable barrierosmosis • solvent (HOH), solute • isotonic, hypertonic, hypotonic • Cytoplasmic membrane protein functions • Food accumulation- group translocation • active transport • Catalysis of metabolic pathways - e.g., electron transport chain • Cell wall component synthesis • Signal transduction - e.g. chemotaxis • CELL WALL • Gram positive organisms: Peptidoglycan, Teichoic acid • Gram negative organisms: Peptidoglycan • Periplasmic gel • Lipoprotein • Outer membrane – Phospholipid monolayer • Lipopolysaccharide • Pores • Peptidoglycan - polysaccharide with amino acid components. N - acetyl glucoseamine, N - acetyl muramic acid, Amino acid side chains, Cross-linking (interbridge) • FLAGELLA - Flagellin, hook, outer rings, inner ring • Rotation: counter clockwise, clockwise, chemotaxis • NUCLEOID – chromosome, haploid, double-stranded, supercoil • CYTOPLASM – water, ribosomes, soluble proteins, enzymes, low molecular weight precursors, RNA, ATP • PILI (SEX); FIMBRIAE (ATTACHMENT) • CAPSULE/GLYCOCALYX • COMPARISON: EUCARYOTES AND PROCARYOTES • SPORULATION – Endospores, durable, inert, survival mechanism, germination

  2. BACTERIAL CELL SHAPE • COCCUS - SPHERE - COCCI • Single - Micrococcus luteus • Diplococcus - Neisseria gonorrhoeae • Neisseria meningitidis • Clusters - Staphylococcus aureus • Streptococcus - Streptococcus pyogenes • BACILLUS - ROD, CYLINDER - BACILLI • Bacillus anthracisANTHRAX • CorynebacteriumdiphtheriaeDIPHTHERIA • [pleomorphic] • SPIRAL • RIGID - SPIRILLA Rhodospirillumrubrum[photosynthetic] • CURVEDVibrio choleraeCHOLERA • FLEXIBLE - SPIROCHETES • TreponemapallidumSYPHILIS • BorreliaburgdorferiLYME DISEASE

  3. MICROORGANISMS Reproduce themselves faithfully and the species continues to occupy its niche in the environment Have the capacity to change genetically Mutation Genetic exchanges permits survival in changing environments

  4. Fig. 3.1 SLONCZEWSKI & FOSTER TEXT

  5. “TYPICAL” BACTERIAL CELL - BINARY FISSION ~1 x 3 µm 0 min 20 min 40 min 60 min PLASMIDS – SMALL EXTRA-CHROMO-SOMAL DNA MOLECULES NOT NORMALLY REQUIRED FOR GROWTH OFTEN CODE FOR TOXINS, DRUG RESISTANCE

  6. ACCUMULATE FOOD Oxidize food Energy Convert food Low molecular weight compounds Amino acids Fatty acids Monosaccharides Nucleotides SYNTHESIZE MACROMOLECULES: Proteins, Lipids, Polysaccharides, RNA, DNA DIVIDE

  7. CYTOPLASMIC MEMBRANE - PHOSPHOLIPID BILAYER outside Hydrophobic fatty acids ~8 nm inside Hydrophilic phosphates FLUID MOSAIC STRUCTURE - VISCOUS ~ 8 nm thick selectively permeable - H2O osmosis - isotonic solutions

  8. NET H2O change OUT IN [H2O] X [solute] Y [H2O] LOW [solute] HIGH [H2O] HIGH [solute] LOW [H2O] X [solute] Y [H2O] HIGH [solute] LOW [H2O] LOW [solute] HIGH none ISOTONIC HYPERTONIC out HYPOTONIC in

  9. CYTOPLASMIC MEMBRANES - FUNCTIONS 1. FOOD ACCUMULATION A. Group translocation (substance modified) (outside) glucose glucose-6-PO4 (inside) B. Active transport Potassium K+ ions METABOLIC PATHWAYS Electron transport chain Chemiosmosis; ATP synthesis 3. CELL WALL COMPONENT SYNTHESIS 4. SIGNAL TRANSDUCTION; e.g., chemotaxis sense change in environment respond to change 5. SECRETION e.g., toxins

  10. CELL WALLS AND CYTOPLASMIC MEMBRANES Gram Positive Gram Negative Teichoic acid Pore Lipopolysaccharide Phospholipid monolayer Lipoprotein Periplasm Phospholipid Bilayer Proteins Cytoplasm

  11. PEPTIDOGLYCAN: REPEATING DISACCHARIDES WITH AMINO ACID SIDE CHAINS N-Acetyl Glucosamine N-Acetyl Muramic Acid Amino acid side chain

  12. L-ALANINE D-GLUTAMIC ACID DIAMINO PIMELIC ACID D-ALANINE

  13. L-ALA D-GLU DAP D-ALA D-ALA DAP D-GLU L-ALA G–M–G–M–G–M–G–M G–M–G–M–G–M–G Polysaccharide INTERBRIDGE between side chains Amino acid side chain INTERBRIDGE: Gram negative - covalent bond amino acids 3-4 Gram positive - penta glycene between amino acids 3-4

  14. HELICAL PEPTIDOGLYCAN CHAIN WITH SIDE CHAINS

  15. MOTILITY 1. SWIMMING Extracellular flagella rotate Escherichia coli 20 - 90 micrometers/sec 2. FLEXING Flagellum located in periplasm rotates, cell flexes as flagellum rotates Treponemapallidum 3. GLIDING Move over solid surfaces without flagella Two forms of gliding: A. Adventurous (twitching) - done by individual cells B. Social - done by many cells in unison

  16. FLAGELLUM (-A) FLAGELLIN rings hook 14 nm x 10 µm Cytoplasmic membrane Outer membrane Peptidoglycan 200 revolutions/sec Counter clockwise - forward swim Clockwise - random tumble Chemotaxis - net movement toward attractant, away from repellent Cells swimming toward attraction tumble less often. Net result movement toward attraction

  17. JUNCTION FLAGELLIN MONOMER FILAMENT HOOK CAP CENTRAL EXPORT CHANNEL BEARINGS L-RING P-RING ROD OUTER MEMBRANE CELL WALL- PEPTIDOGLYCAN H+ PERIPLASMIC SPACE CYTOPLASMIC MEMBRANE H+ MS-RING STATOR/MOTOR (CROSS-SECTION) C-RING (CROSS SECTION) EXPORT APPARATUS SECRETION ATP ADP ROTOR: C, MS, ROD, HOOK, FILAMENT

  18. FILAMENT HOOK L-RING P-RING OUTER MEMBRANE PEPTIDOGLYCAN LAYER MS-RING ROD PERIPLASMIC SPACE CYTOPLASMIC MEMBRANE STATOR CROSS-SECTION C-RING CROSS-SECTION

  19. STATOR - MOTOR C-RING

  20. Several mechanisms, one of which is pilus extension (attachment to the solid surface) and pilus retraction. (Type IV pili.) Examples of twitching: Neisseria gonorhoeae- spread over body cell surfaces (?) Pseudomonas aeruginosa- spread over body cell surfaces (?) 0.2 µM/sec Gram negative Opportunistic pathogen Burn victims - bacteremia Cystic fibrosis - chronic lung infection Ulcerative keratitis - contact lens Example of social gliding: Myxococcusxanthus- cells form fruiting bodies = clumps containing spores (Note: M. xanthuscan also twitch) 4. SWARMING: Depends on flagella Cells move in unison over solid surface Escherichia coli, Salmonella enterica

  21. ADHESIVE ORGANELLES Contain adhesin (protein which binds something) Function: attachment Kinds: 1. pili/fimbriae 2. non-pilus adhesin (surface protein) PILI 7nm x 1µm 1 x 3 µm examples: Escherichia coli sex pili - attach to female

  22. P PILUS - Escherichia Coli CYSTITIS (BLADDER) Sticks to glycolipid on uroepithelial cells and RBC (11 genes) Adhesin Linkers Central hole Pilus Usher (pore) Outer membrane Periplasm Cytoplasmic membrane

  23. Hemophilus influenzae HIB Pilus Respiratory epithelium E. coli P Pilus Uroepithelial cells J. Bacteriol. 184.17. cover 2002

  24. Aggregate - nutrients Growth Starvation + nutrients Fruiting body Spores MYXOCOCCUS XANTHUS FORMS SINGLE-SPECIES BIOFILMS AND EXHIBITS SOCIAL BEHAVIOR

  25. MyxococcusxanthusFRUITING BODY DEVELOPMENT

  26. CAPSULE / GLYCOCALYX Streptococcus pneumoniae Polysaccharide Pathogenicity factor

  27. NUCLEOID - E. coli • 1 chromosome - haploid ~ 1100 µm circumference Supercoil - double strand • 4.6 x 106nucleotides / strand ~ 5,300 genes ~ 3 x 109molecular weight 660 molecular weight / nucleotide pair CYTOPLASM HOH, soluble materials - low molecular weight precursors Enzymes, ribosomes, RNA [transfer; messenger], ATP

  28. PROKARYOTE GENOMES Genome = all genetic information of an organism Number Nucleotide Pairs Number Genes E. coli 4.6 x 106 ~ 5,300 Haemophilus 1.8 x 106 ~ 1,800 influenzae Methanococcus 1.7 x 106 ~ 1,800 jannaschii (archea)

  29. E. COLI NUCLEOIDS

  30. BACTERIAL (E. COLI) CELL COMPOSITION NUMBER MOLECULES MOL WT % OF DIFFERENT PER CELL CELL KINDS OF MOLECULES DNA 1 1-2 3 X 109 1 PROTEIN 5,000 2 X 106 3 – 4 X 104 15 RNA (TOTAL) 6 RIBOSOMAL 3 20,000 EACH TRANSFER 60 200,000 2,000 MESSENGER 600 1500 PHOSPHOLIPID ~MANY 22,000,000 700 3 RIBOSOMES 1 20,000 PEPTIDOGLYCAN 1 1 ~10 X 109 1 OTHER CELL WALL COMPONENTS, LOW MOLECULAR WEIGHT PRECURSORS, VITAMINS WATER 70

  31. EUKARYOTES PROKARYOTES 1. True nucleus chromosomes in nuclear membrane Introns common 2. Divide by mitosis 3. Sexual reproduction; meiosis (eggs, sperm) 4. Mitochondria 5. Chloroplasts 6. Cell walls animals - none plants - cellulose fungi - chitin 7. Ribosomes - 80S 8. Size - 8 to 100 micron diameter 1. Nucleoid Introns rare 2. Divide by binary fission 3. Primitive sex 4. None 5. None - chromatophores 6. Present, with peptidoglycan 7. Ribosomes - 70S 8. Size - 1 x 3 microns Macroscopic microbe - Epulopisciumfishelsoni > 50 micron diameter > 500 micron length

  32. ENDOSPORES Dormant, inert, durable Resist chemicals (e.g., bleach), heat, drying, radiation Formed by growing cells Nucleoid Cell membrane spore coat GERMINATION-spores resume metabolism and form growing cells

  33. DISEASES CAUSED BY EXOTOXINS PRODUCED BY • SPORE- FORMING ORGANISMS • ANTHRAX - Bacillus anthracis • BOTULISM - Clostridium botulinum • ANAEROBE - GROWS WITHOUT • MOLECULAR OXYGEN • TETANUS - Clostridium tetani • ANAEROBE

  34. ANTHRAX- (disease of cattle, sometimes spread to humans) Cutaneous anthrax: Bacillus anthracisspores in soil or contaminated animal products. Enter body through wounds, germinate and grow. Set up local infection (sometimes it spreads) Pulmonary anthrax: Spores are breathed, germinate in the lungs, infect lungs, massive swelling, rapid death Toxins: Pore Forming Protein Assembles in Cytoplasmic Membrane; Edema Factor, Lethal Factor Bind Pore; Endocytosis into cells; EF and LF exit through pore into cytoplasm; Massive swelling; Inhibition of host immune system ability to respond to infection

  35. TETANUS- Clostridium tetanispores - ubiquitous in soil • Enter body through wounds; germinate; grow at the site of infection; secrete neurotoxin. • Neurotoxin processed (cleaved) to heavy & light chains; heavy chain binds receptor on nerve cell at site of injury and creates pore. • Light chain is protease, enters pore; spreads up nerves to spinal cord; fixed at “presynaptic inhibitory motor neuron” • Disrupts movement of nerve cell vesicles containing neurotransmitters needed to dampen nerve impulses. Causes involuntary contractions; muscles • continue to work. (convulsions - spastic paralysis = tetany); asphyxiation; death; • toxin is tetanospasmin • Neonatal tetanus: 500,00 people die/year in the world • Tetanus vaccinations in U.S. (DT or DPT or DaPT)

  36. BOTULISM- Clostridium botulinumspores on vegetables, smoked fish, similar items contaminated • Spores survive home canning/preservation process, • Germinate in the anaerobic environment of the canned food, cells grow and secrete neurotoxin • People ingest the toxin, absorb it from their intestine. • Neurotoxin – similar to tetanus toxin; One protein processed to heavy chain (binds peripheral nerve cell; creates pore); Light chain is protease; acts at end of peripheral nerve, disrupts nerve impulse transmission to muscle. • Result is flaccid paralysis; respiratory failure; DEATH • Treatment - anti botulism antitoxin

  37. TAKE AWAY: STRUCTURES OF BACTERIAL CELLS; THEIR FUNCTIONS AND MACROMOLECULAR COMPOSITIONS MOTILITY MECHANISMS SPORULATON PROCESS & DISEASES RESULTING FROM ORGANISMS WHICH FORM SPORES UNDERSTAND: WHY STRUCTURES ARE USEFUL HOW EACH ACCOMPLISHES ITS FUNCTION HOW FLAGELLUM ROTATION IS ACCOMPLISHED HOW A BIOMOLECULAR MACHINE WORKS ROLE OF GENETIC INFORMATION SPORULATON IS DEVELOPMENTAL PROCESS – TWO CELL TYPES

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