In this project, we have a considerable ongoing
effort. This work will identify genes and ultimately physiological activities
that are critical to the function of anaerobic bacteria that live and grow
in contaminated sediments. Our hypothesis is that sediment dwelling microorganisms
have unique functions, encoded at the genetic level that are manifest only
during exposure to contaminated environments. Further, we believe that
these activities are not detectable using traditional in vitro laboratory
incubations and therefore we are studying the bacteria under more natural,
in situ, conditions.
We are identifying genes of sulfate reducing bacteria
(SRB) whose expression is necessary for the survival and activity of these
organisms in contaminated environments. This involves the extrapolation
of a molecular approach that has already proven successful for identifying
genes expressed by pathogens only when these organisms are growing in a
suitable host (in situ) and not when the organisms are in culture. Our
approach takes on an ecological perspective. We are asking which genes
are expressed by sulfate reducers when they are exposed to and/or degrading
a myriad of contaminants in sedimentary systems as opposed to those genes
that may be expressed in laboratory cultures.
Recent Publications:
Groh, J.L., L.R. Krumholz. Multidrug resistance function of the mexF gene in Shewanella oneidensis MR-1. Appl. Environ, Microbiol. (submitted).
Groh, J.L., L.R. Krumholz.. Factors influencing growth and survival of Shewanella oneidensis MR-1 in sediments. Environ, Microbiol. (submitted).
Groh, J.L., Q. Luo, J.D. Ballard and L.R. Krumholz. Bacterial genes that promote in situ sediment survival. Appl. Environ, Microbiol. (submitted).
Groh, J.L., Q. Luo, J.D. Ballard and L.R. Krumholz. 2005. Adaptation of microarray technology for Signature Tagged Mutagenesis (STM) of Desulfovibrio desulfuricans G20 and Shewanella oneidensis MR-1 in anaerobic sediment survival experiments. Appl. Env. Microbiol. 71(11): 7064-7074.
Chang, I.S., J. L. Steger, M. M. Ramsey, J.D. Ballard and L.R. Krumholz. 2004. Differential Expression of Desulfovibrio vulgaris genes in response to Cu(II) and Hg(II) toxicity. Appl. Environ. Microbiol. 70:1847-1851.
Elias, D.A., J.M. Suflita, M.J. McInerney and L.R. Krumholz. 2004. The periplasmic cytochrome C 3 of Desulfovibrio vulgaris is directly involved in H 2 mediated metal-, but not sulfate-reduction. Appl. Environ. Microbiol . 70(1):413-420.
Chang, I., J.D. Ballard and L.R. Krumholz. 2003. Evidence for Chimeric sequences during random arbitrarily primed PCR. J. Microbiol Meth . 54:427-431.
Steger, J.L., C. Vincent, J.D. Ballard and L.R. Krumholz. 2002. Desulfovibrio sp. Genes involved in the metabolism of Hydrogen and Lactate. Appl. Environ. Microbiol. 68(4):1932-1937.