Lack of detectable polyamines in an extremely halophilic bacterium.

Polyamines (putrescine, spermidine, spermine and other analogs) were not detectable by the dansylation procedure coupled with HPLC analysis in an extremely halophilic bacterium, Halobacterium halobium. Based on the detection limit of this analytical method, we estimated that the polyamine content in H. halobium, if present, was less than 0.06% of that of E. coli. Putrescine uptake and the metabolic conversion of ornithine or arginine to polyamines were negligible in this bacterium. In a H. halobium cell-free extract, a saturated amount of KC1 was needed for poly(U) directed polyphenylalanine synthesis; neither putrescine nor spermidine could replace KC1. These results suggest that polyamines may play an insignificant role in the growth of this halophilic bacterium.