engleski

Temperature regulated changes in fatty acid composition of some marine bacteria

Background and purpose: Temperature, one of the most important environmental factors affecting growth and development of bacteria, can largely modify its fatty acid composition. Temperature experiment was performed on bacteria belonging to Proteobacteria, and Cytophaga-Flavobacter complex, occurring in succession during the aggregate aging process and degradation of mucous matrix. Since certain membrane fluidity is required for the uptake and assimilation of substrates bacteria must modify the fatty acid composition according to the environmental temperature. These modifications are important to understand because of their consequences on bacterial cell viability and maintenance of the cell function. Material and methods: The bacterial isolates were grown in marine broth at 10°C, 20°C and 30°C. The cellular fatty acids were analyzed by capillary GC/MSD. Results: In proteobacterial and in CF-complex strains the most common response to decreasing temperature were unsaturation of the straight-chain fatty acid and alteration of branching from iso to anteiso, respectively. In some of the related strains shift from cis to trans isomers of C16:1 fatty acid, and increase in unsaturated straight-chain and branched- chain occurred additionally imparting the proper fluidity of the membrane. Conclusions: Two bacterial groups studied showed different mode of thermal adjustment of the membrane fluidity depending on characteristic fatty acid system of bacterial cell (unsaturated/branched). All strains show the viability in the temperature range studied (10°C to 30°C). Their characteristic fatty acid pattern was not affected.

Fatty acid composition; marine bacteria; temperature

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