RT Journal Article SR Electronic(1) A1 Bogdanova, E. S. A1 Bass, I. A. A1 Minakhin, L. S. A1 Petrova, M. A. A1 Mindlin, S. Z. A1 Volodin, A. A. A1 Kalyaeva, E. S. A1 Tiedje, J. M. A1 Hobman, J. L. A1 Brown, N. L. A1 Nikiforov, V. G.YR 1998 T1 Horizontal spread of mer operons among Gram-positive bacteria in natural environments JF Microbiology, VO 144 IS 3 SP 609 OP 620 DO https://doi.org/10.1099/00221287-144-3-609 PB Microbiology Society, SN 1465-2080, AB Horizontal dissemination of the genes responsible for resistance to toxic pollutants may play a key role in the adaptation of bacterial populations to environmental contaminants. However, the frequency and extent of gene dissemination in natural environments is not known. A natural horizontal spread of two distinct mercury resistance (mer) operon variants, which occurred amongst diverse Bacillus and related species over wide geographical areas, is reported. One mer variant encodes a mercuric reductase with a single N-terminal domain, whilst the other encodes a reductase with a duplicated N-terminal domain. The strains containing the former mer operon types are sensitive to organomercurials, and are most common in the terrestrial mercury-resistant Bacillus populations studied in this work. The strains containing the latter operon types are resistant to organomercurials, and dominate in a Minamata Bay mercury-resistant Bacillus population, previously described in the literature. At least three distinct transposons (related to a class II vancomycin-resistance transposon, Tn 1546, from a clinical Enterococcus strain) and conjugative plasmids are implicated as mediators of the spread of these mer operons., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-144-3-609