Adaptational changes in cellular fatty acids of cultured bacteria as a response to trophic differences

Abstract

           The adaptational changes in cellular fatty acids and morphology of γ-Proteobacteria belonging to different genera (Vibrio, halomonas, Pseudoalteromonas) isolated from northern Adriatic waters and cultured in four media (Marine Broth, R2 Broth and tenfold dilutions of both) were investigated. The bacterial strains with identical 16S rRNA sequences isolated from different waters used differ- ent mechanisms, or different extent of the same mechanism, to adapt their growth in equal culture media. In contrast, a similar growth strategy in each of the used cultures was employed by different strains isolated from the same water body. Divergence in nutrient quality and requirement in cul- tures from that presented in the bacterias’ natural environment induced important changes in cel- lular fatty acids; (i) unsaturation, (ii) cis to trans isomerisation, (iii) chain elongation (iv) branching and/or morphology (Winnie-the-Pooh effect) or even cell division blocking. The results strongly suggest that growth and the appropriate cellular response of bacteria in culture is predetermined by nutritional conditions in their true environment and can be useful for interpretation of trophic differences between proximate environments.