Previous Article | Next Article ![]()
Appl. Environ. Microbiol., Dec 1997, 4914-4919, Vol 63, No. 12
KD Bruce
Bacterial mer (mercury resistance) gene subclasses in mercury-polluted and
pristine natural environments have been profiled by
Fluorescent-PCR-restriction fragment length polymorphism (FluRFLP). For
FluRFLP, PCR products were amplified from individual mer operons in
mercury-resistant bacteria and from DNA isolated directly from bacteria in
soil and sediment samples. The primers used to amplify DNA were designed
from consensus sequences of the major subclasses of archetypal
gram-negative mer operons within Tn501, Tn21, pDU1358, and pKLH2. Two
independent PCRs were used to amplify two regions of different lengths
(merRT(Delta)P [ca. 1 kb] and merR [ca. 0.4 kb]) starting at the same
position in merR. The oligonucleotide primer common to both reactions
(FluRX) was labelled at the 5(prm1) end with green (TET) fluorescent dye.
Analysis of the mer sequences within databases indicated that the major
subclasses could be differentiated on the basis of the length from FluRX to
the first FokI restriction endonuclease site. The amplified PCR products
were digested with FokI restriction endonuclease, with the restriction
digest fragments resolved on an automated DNA sequencing machine which
detected only those bands labelled with the fluorescent dye. For each of
the individual mer operon sources examined, this single peak (in bases)
position was observed in separate digests of either amplified region. These
peak positions were as predicted on the basis of DNA sequence. mer PCR
products amplified from DNA extracted directly from soil and sediment
bacteria were studied in order to determine the profiles of the major mer
subclasses present in each natural environment. In addition to peaks of the
expected sizes, extra peaks were observed which were not predicted on the
basis of DNA sequence. Those appearing in the restriction endonuclease
digests of both study regions were presumed to be novel mer types. Genetic
heterogeneity within and between mercury-polluted and pristine sites has
been studied by this technique. Profiles generated were highly similar for
samples taken within the same soil type. The profiles, however, changed
markedly on crossing from one soil type to another, with gradients of the
different groupings of mer genes identified.
Copyright © 1997, American Society for Microbiology
Analysis of mer Gene Subclasses within Bacterial Communities in Soils and Sediments Resolved by Fluorescent-PCR-Restriction Fragment Length Polymorphism Profiling
School of Biological Sciences, Donnan Labs, University of Liverpool, Liverpool, L69 7ZD, United Kingdom
This article has been cited by other articles:
| J. Bacteriol. | Microbiol. Mol. Biol. Rev. | Eukaryot. Cell | All ASM Journals |
|---|