# BIODEGRADATION OF MERCURIAL ANTISEPTICS AND PESTICIDES

> **NIH NIH R01** · UNIVERSITY OF GEORGIA · 1987 · $142,884

## Abstract

Genes for resistance to and biodegradation of organomercurials (Omr)
including the antiseptic merthiolate, the disinfectant phenylmercuric
acetate, and the neurotoxic fungicide methyl mercury, are often found on
bacterial plasmids along with resistance to inorganic compounds such as
HgCl2.  Though inorganic mercury resistance (Hgr) has been studied
extensively, much less is known about organomercury resistance.

Two years ago we began to study the organomercury resistance determined by
the conjugative IncM plasmid, R831b.  Though 90 kb in size, R831b is the
smallest naturally occurring plasmid which carries the Omr locus.  Using
transposon mutagenesis and restriction enzyme analysis we have mapped the
only two selectable markers carried by R831b, Hgr and Omr.  We found that
these loci are separated by 13.5 kb despite the fact that the enzymes they
encode are regulated co-ordinately.  We have sub-cloned Omr into pBR322
which is compatible with the Hgr mini-IncM replicon we had previously
cloned and have begun to construct fine structure restriction and deletion
maps of both loci.  During the last year of this present grant we will
complete the restriction enzyme mapping of these loci and generate both lac
and galK fusions in the parental plasmid and in sub-cloned derivatives.

We propose for the long term:  (1) to use minicell polypeptide analysis to
characterize the gene products of the Omr and Hgr loci of R831b; (2) to
examine regulation of Omr/Hgr expression using insertion and deletion
mutants and lac and galK fusions of both the homologous system (i.e. the
R831b loci) as well as of a heterologous system (i.e. including both R831b
and the correlate loci of the mer operon of NR1) and to isolate the cis-
and trans-acting regulatory elements of these loci in R831b and compare
them with those of the NR1 mer operon; (3) to employ the Omr and Hgr DNA as
probes to explore the occurrence of such loci in our large collection of
multiply metal resistant bacteria; and (4) to sequence the Omr and Hgr loci
of R831b.  No Omr locus has yet been sequenced and though Hgr loci from
plasmid NR1 and the related transposon Tn501 have been sequenced, our
polypeptide data, DNA hybridization data (ours unpublished and T. Barkay,
personal communication) and immunodiffusion data (S. Silver, personal
communication) indicate that the Hgr locus of R831b is not closely related
to that of NR1/Tn501.

## Key facts

- **NIH application ID:** 3128574
- **Project number:** 5R01AI019221-06
- **Recipient organization:** UNIVERSITY OF GEORGIA
- **SAM.gov UEI:** NMJHD63STRC5
- **Principal Investigator:** Anne O'Neill Summers
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $142,884
- **Award type:** 5
- **Project period:** 1982-09-01 → 1988-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3128574

## Citation

> US National Institutes of Health, RePORTER application 3128574, BIODEGRADATION OF MERCURIAL ANTISEPTICS AND PESTICIDES (5R01AI019221-06). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3128574. Licensed CC0.

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