Lecture 9: Bacterial Diversity Reading assignments in Text: Lengeler et al. 1999 Text:pages 674-676...
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Transcript of Lecture 9: Bacterial Diversity Reading assignments in Text: Lengeler et al. 1999 Text:pages 674-676...
Lecture 9: Bacterial Diversity
Reading assignments in Text: Lengeler et al. 1999
Text: pages 674-676 Bacterial diversitypages 700-704 Phylogenetic treespages 704-716 Early life/ evolutionpages 723-728 Food in the real worldpages 746-750 Biofilmspages 754-761 Cooperation and methanogenspages 763-774 Bugs in waterpages 775-778 Bugs in sedimentspages 779-784 Bugs in soilpages 784-792 Bugs in extreme environmentspages 879-882 Bugs in food productspages 907-908 Bio-treatment
Lecture 8Text: pages 586-601 Sporulation
pages 627 Secondary metabolism
Lecture Overview
Bacterial populations (lab conditions)
Metabolism
GROWTH
Bacteria as single cells (“cell cycles”)
DifferentiationSymbiosis
Sporulation
Bacterial Environments and Diversity
Spreading sea-floor
Alvin
Smoker/hot vent~15x106 yr cycle “tube worms” + ecosystem
Deep-sea symbiosis between lithotrophs and eukaryotes
H2S O2 ATP/NADPH CO2 fixn = food
Epulopiscium fishelsonii (the big one)
250 microns
“Molecular” 16S rRNA phylogenic analysis
Value?
c
d
a
b
“Wt” reference
“mutation”
A sequencing example:
Any organism, even non-culturable
a
b
cd
1
23
Analysis
Un-rooted “tree”
The 16S rRNA “Tree of Life”
3 Kingdoms1 2
3
E. fishelsonii ~ B. subtilis
Multi-cellularnarrow diversity
People ~ Yeast
Mitochondria ~ Bacteria
Chloroplasts ~ Cyanobacteria
Many diverse non-culturable
Root maybe a Thermo-phile
Archaea versus Bacteria (are they really different?)
Biosynthesis, amino acids, etc.
Yes No
XCell division
X
Membranes X(unique)
Polymerization DNA X(eukayotic)
RNA X(eukayotic)
Translation X(eukayotic)
Chemistry / Cofactors (unique) X
Signaling, Chemotaxis X
Photosynthesis X(unique)
Operons, small circular chromosomes X
Human pathogens? ?(None known)
Bacterial numbers and distributions
(from Whitman et al. 1998 PNAS 95:6578.)
Total = 4-6 x 1030 cells
Water 12 x 1028 cells
Sediments 355 x 1028 cellsBiofilms
Soil 26 x 1028 cells
Deep earth 25-250 x 1028 cells
Air ~5 x 1019 cells
People 6 x 109 4 x 1023 colon
Cows 1 x 109 29 x 1023 rumenTermites 2 x 1017 7 x 1023 gut
Animals Bacteria
Symbiosis
Growth / Turnover in Days (not DT)
Water shallow 16
Water deep 300
Phototrophs 1.5
Sediments 500,000
Soil 900
Animals ~1
adhesion threads
Deinococcus geothermalisThis pink-pigmented bacterium often forms biofilms. This electron micrograph shows cells attached on polished stainless steel in sterilized paper machine water at 45C.
Actinobacillus actinomycetemcomitans (stained with crystal violet)Biofilm colony on polystyrene petri dishReleases cells to form new colonies
Biofilm spread
4 mm
Imprint of a clover leaf on a methanol mineral salts plate incubated at 30C for 2 days to allow outgrowth of the pink-pigmented Methylobacterium strains.
Natural bacterial distributions
Sauerkraut
Cabbage 40
NaCl 1Cover with water, cold w/o air
~ weeks
1 NaCl, lysis, microbes digest polysaccharides proteins
2 Complex fermentation period
3 Leuconostoc mesenteroides take over
Heterolactic fermentation:mannitol, acetic acid, ethanol, CO2, etc. pH~5.5
4 Acidophiles, e.g. Lactobacillus sps. take over
Homolactic fermentation ~ 0.15 M lactate
? So what ?