1 / 17

Prokaryote Lifestyle

Prokaryote Lifestyle. 1) rapidly reproducing cells: 1-3 h 20-50 minutes/generation in E. coli deep soil bacteria: 70-100 years! (1000 yrs) 2) tremendous growth if: enough nutrients not poisoned by metabolic waste 3) adaptation to changing environment.

colum
Download Presentation

Prokaryote Lifestyle

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. Prokaryote Lifestyle • 1) rapidly reproducing cells: 1-3 h • 20-50 minutes/generation in E. coli • deep soil bacteria: 70-100 years! (1000 yrs) • 2) tremendous growth if: • enough nutrients • not poisoned by metabolic waste • 3) adaptation to changing environment

  2. Example of sharing plasmid: Microbes in Dry Valleys of Antarctica • harsh conditions, slow growth • UV, dry, windy, metals • gen. time 100 days • live within rock • 1/3 strains resistant to chromium, metals • new strains get plasmid with genes for resistance

  3. diversity of prok. in soils • sequencing study • pH is most critical factor • neutral soils most diverse • Peruvian rainforest acidic, less diversity

  4. Examples of Quorum Sensing • flashlight fish (Fig 27.20) • Vibrio fischeri • mutualism (both benefit) • cholera • Vibrio cholerae • parasitism (parasite eats host) • pathogen (parasite causes disease) • exotoxin secreted • Idea: instead of antibiotics, stop communication

  5. Endotoxins from gram negative bacteria: lipopolysaccharides released when cell dies Fig 27.3, p 557

  6. Swarming • coordinated, rapid movement • cover solid surface • eg. Rhizobium etli

  7. complex behavior • Myxobacteria • mxyo = slime • when no nutrients • swarm, aggregate • release spores • huge genome

  8. complex behavior • Myxobacteria • mxyo = slime • when no nutrients • swarm, aggregate • release spores • huge genome

  9. Biofilms • community w/complex structure • lose flagella, excrete matrix • polysaccharides, proteins, nucleic acids • diverse, resistant • examples • medical implants, ships hulls • dental plaque, cow’s rumen

  10. human microbiome • body is ecosystem. many symbioses • mostly commensalism, mutualism • 500—1000 species of bacteria • 10x as many bacterial as human cells • unique combination of prokaryotes • diversity: skin, gut (mouth-> intestines) • Bacteroides thetaiotaomicron • Helicobacter pylori causes stomach ulcers • makes ammonia to buffer stomach acid • other chronic diseases?

  11. problems with antibiotics • 1) disrupt native prokaryotes • make vitamins, digest food • compete with pathogens • 2) select for resistant prok. • a few w/resistance mutation survive • reproduce rapidly without competitors

  12. prok evolve so antibiotics won’t work • Some resistant to many antibiotics: • Mycobacterium tuberculosis (prisons) • methicillin resistant Staph. aureus (hosp) • Antibiotics in environment: waste from humans & factory farm animals • good news: revert quickly without

  13. how to minimize problem • take antibiotics only when necessary • use bleach: true antibacterial—acts like cannon (antibiotic has specific target) • avoid “antibacterial” products incl. triclosan • soaps, toothpaste, socks, cutting boards • wash hands with ordinary soap • avoid alcohol-based soapless cleaners & too much hand washing • remove oils (natural defense)

  14. Application: genetic engineering with Agrobacterium • Infects plants w/plasmid (Fig 20.25) • introduce genes • (eg. resistance to virus) • ecological consideration: • unintended results? • Bacillus thuringiensis Bt toxin • insecticide • requires gut bacteria in insect

  15. Methanotrophs • use methane for energy & carbon • anaerobic archaea • aerobic proteobacteria • cycle: use methane from methanogens or from underwater volcanoes • enzyme breaks down methane and 250 other compounds: bioremediation • can convert toxic waste to salt & CO2

  16. Chemical Cycles • prok recycle nutrients: N, P, S, CH4 • parasites absorb nutrients from living hosts • saprobes absorb nutrients from dead organic matter • metabolically critical • decomposers, recyclers • decomposition of waste products & organisms

  17. Compost: example of nutrient recycling • C (brown plants) • N (green plants) • air & water • fungi, prokaryotes • esp actinobacteria • worms, insects

More Related