1 / 23

Lecture 8: Bacterial Differentiation: Sporulation

Lecture 8: Bacterial Differentiation: Sporulation. Reading assignments in Text: Lengeler et al. 1999 Lecture 8 Text: pages 586-601 Sporulation Text: pages 627 Secondary metabolism Lecture 7 Text: pages 792-799 Gut bugs Text: pages 276-277, 800 Bacterial Lux

shauna
Download Presentation

Lecture 8: Bacterial Differentiation: Sporulation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lecture 8: Bacterial Differentiation: Sporulation Reading assignments in Text: Lengeler et al. 1999 Lecture 8 Text: pages 586-601 Sporulation Text: pages 627 Secondary metabolism Lecture 7 Text: pages 792-799 Gut bugs Text: pages 276-277, 800 Bacterial Lux Text: pages 498-499 Quorum sensing Text: pages 801 Bacteria and plants Text: pages 865-868 Agrobacterium Text: pages 275 Toxic oxygen Text: pages 807 Nitrogen cycle Text: pages 851-862 Rhizobia and Cyanobacteria

  2. Lecture Overview Metabolism GROWTH Bacterial populations (lab conditions) Bacteria as single cells (“cell cycles”) Differentiation Symbiosis Sporulation

  3. Bacillus subtilis growth and sporulation Log(N) 3 4 inoculate 2 time 1 1 log growth, symmetric cell division 2 Gain motility Quorum sensing 3 Gain genetic competence 4 Sporulate, asymmetric cell div ~7 hours VII stages B Gene (A, B, C …) Genetics: III Stage (0, I, II, III, IV, V, VI) Relatives: B. cereus, B. anthracis >200 genes/proteins Spo

  4. B. subtilis sporulation stages 2 chromosomes, axial fibers 0 I 2 cells, cell wall II Engulfment III Double membrane D M Cortex IV Coat V-VI Spore maturation Mother cell lysis (DNA) VII

  5. Bacillus subtilis engulfment SpoIIIE-GFP fusion protein (pink) Membranes (red) DNA (blue)

  6. Sigma factor saga s A Log/ veg. Growth s H s s s s 0 E E F F Active s I G II Inactive III s K Active IV V-VI ? Signals Check-points VII ? decision Inactive ? activation

  7. Deciding to sporulate s s 3 ? A H 2 1 1 Starvation: 2 Cell density: Ok ? Trouble ahead ! 3 Chromosomes: ? sporulate What is monitored? [GTP] = (C, N, P) Not ppGpp “quorum sensing” peptides Food low, [cell] low Food low, [cell] high 2 undamaged, complete, and polar placement.

  8. Decision committee ~~~~~~~ ~P Inputs 1, 2, 3, ? Spo0F Spo0B ~P relay Spo0A~P Spo0A (+ feed back ) TGNCGAA ~P relay genes (+ feedback) s s s H E F New genes mRNA DNA “developmental switch” (inactive, “in waiting”) Histidine Kinases KinA, KinB New genes: Asymmetric division

  9. Activating the sigma factors Spo0A~P DNA SpoIIAA SpoIIAB SpoIIE Anti-sigma (ATP) SpoIIAA SpoIIAB Released in “daughter” forespore compartment (ADP) Anti-Anti-sigma Many genes s s s E F F New genes mRNA SpoIIGA, SpoIIR proteases Pro- cut off Active Sigma Mother Daughter Pro-Sigma Protein

  10. Sigma-K activation in mother cell Split gene 42 kb Recombinase gene Joined gene protein Pro-sigma-K sigma-K Pro- Mother Daughter

  11. Sigma factor summary s A Log/ veg. Growth s H s s s s 0 E E F F Active s I G II Inactive III s K Active IV V-VI Signals Check-points VII decision Inactive activation

  12. B. subtilis versus E. coli s s s 5 Smaller cells Spores Fewer ribosomes Compact DNA Cyclopropane fatty acids Hard cortex Programmed mother cell death Cell death Genetic competence (sex) Hypervariation ?

  13. Other sporulating bacteria Crystal toxin Bacillus thuringiensis Neurotoxins 1 gram kills a billion hamsters Clostrium botulinum “Jurassic Park” experiment Endospores 2 cells make 1 spore Exospores 1 cell makes 1 spore (not as durable) Streptomyces coelicolor Gram(+), fungus-like myceleum, antibiotics Myxococcus xanthus Gram(-), wolf-pack gliding, social interactions

  14. Streptomyces coelicolor “smell like soil”

  15. Myxococcus xanthus Germinate starvation Travel 3 Fruiting Body (exospores) 2 Aggregate 1 “wolf pack” “big stomach” feeding behavior, ~105 cells Type IV pili S-motility A-motility Slime jets A-signal (Quorum sensing) C-signal (contact, packing, alignment) Ripple /waves Motto Eat together, spore together, move together

  16. Stigmatella aurantiaca fruiting body on a piece of decaying forest wood (scanning electron micrograph)

More Related