mesophile = middle temperature eg- E.coli , optimum = 39 degrees - adapted to host , not environment
thermophile = Geobaccus sterothermophilus - used in sterilization tests , put organism into autoclave on plates , take out - if organism grows , something wrong with autoclave
hyperthermophile - survive extremely hot environments eg- pyrolobus fumarii - start growing at 90 degrees , can cultivate in autoclave but not common - would contaminate lots
hyperthermophile - thermococcus celer - single membrane with S-layer
S-layer = surface layer , 2D protein crystals , 3 types - P2 - tiled square , P3 - square , P6 - honeycomb ( most common ) - not in model organisms , cover whole cell - 10% of total proteins , primitive cell envelope , negative charge ( so need Na+ / K+ )
thermophile = organism that can live at or near the maximum temperature for its taxonomic group
thermophilicmicrobes = grow above 55 degrees , thermophilic eukaryotes = grow above 62 degrees ( very few - normally fungi ) - most are prokaryotes
above 80 degrees all thermophiles are archaea ( some exceptions ), above 90 degrees are hyperthermophiles - all archaea
thermotoga = hyperthermophilebacteria - have baloon shaped space on outside of cell - structure made by S-layer , for uptake of substrates , small genome - aquired most from archaea for survival at high temperatures
most hyperthermophiles are anerobes - oxygenless soluble in water at high temps , electron acceptor is sulphur in environment
lipid membrane composition determines growth temp , low temp - lipids in gel state - rigid , high temp lipids in liquid crystalline state - membranes disordered
normally , bacterial lipids are ester bonded , fluidity of membrane due to fatty acid composition - how they pack together determines fluidity
As temperature increases in mesophilic bacteria , fatty acid chain length is increased , decreases in unsaturated ( double bond ) fatty acids , moreiso than ante-iso branched fatty acids ( iso branched at end - doesnt interfere with structure - ante-iso does - less stable
bacterial thermophiles - long chains , no unsaturated FA , iso branched ( at end ) FA
thermophilic archaea - ether bonded , fixed hydrocarbon chain 20 or 40 C
B) iso-branched fatty acid - no membrane interference - methyl group at end