||Environmental Significance of the Potential for 'mer' (Tn21)-Mediated Reduction of Hg (2+) to Hg in Natural Waters.
Barkay, T. ;
Liebert, C. ;
Gillman, M. ;
||Technical Resources, Inc., Gulf Breeze, FL.;Environmental Research Lab., Gulf Breeze, FL.
||EPA-R-813589; EPA/600/J-89/166 ; CONTRIB-660
Aquatic microbiology ;
Natural waters ;
Fresh water ;
Salt water ;
Deoxyribonucleic acids ;
Water pollution effects(Animals) ;
Environmental impact ;
Microbial sensitivity tests ;
Bacterial genes ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
The role of mer(Tn21) in adaptation of aquatic microbial communities to Hg2+ was investigated. Elemental mercury was the sole product of Hg2+ volatilization by freshwater and saline microbial communities. Bacterial activity was responsible for biotransformation because most microeukaryotes did not survive the exposure conditions, and removal of larger microbes (> 1 microgram) from adapted communities did not significantly (P > 0.01) reduce Hg2+ volatilization rates. DNA sequences homologous to mer(Tn21) were found in 50% of Hg2+ resistant bacterial strains representing two freshwater communities, but in only 12% of strains representing two saline communities (difference highly significant, P < 0.001). Thus, mer(Tn21) played a significant role in Hg2+ resistance among strains isolated from freshwaters where microbial activity had a limited role in Hg2+ volatilization. In saline environments where microbially mediated volatilization was the major mechanism of Hg2+ loss, other bacterial genes coded for the biotransformation. (Copyright (c) 1989 American Society for Microbiology.)