DIFFERENTIALLY TRANSCRIBED REGIONS OF HALOFERAX-VOLCANII GENOME DEPENDING ON THE MEDIUM SALINITY

To identify genomic regions involved in osmoregulation in the extremel y halophilic archaeon Haloferax volcanii, we used a technique which in volves hybridization of cDNAs obtained at different salinities against a cosmid library of the organism. Both low and high salt concentratio ns trigger differential expression; however, adaptation to low salinit ies seems to elicit a wider response. The presence of a large domain w ithin the largest of the megaplasmids with a strong response to low sa lt concentrations is noteworthy.