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Kathy Nipper

Graduate Student
Department of Biology
The University of Mississippi

B.S. 1967. M.S.C.W., Columbus, MS.;MT(ASCP) internship, Druid City Hospital, Tuscaloosa, AL;1968. MSNS 2002. Delta State, Cleveland, MS.
Ph.D. program directed by Dr. D'Surney

Office: 526 Shoemaker

Classes Currently Teaching:
Bisc 104 (second summer session), 10:00 AM-11:50 AM


The alternative sigma factor Rpos is involved in global regulation of the genes necessary for entry and survival of stationary phase, and is important in gene transcription during environmental stresses such as oxidative stress, adverse pH, and starvation in many prokaryotes. Interestingly, this sigma factor is also necessary for fitness of certain bacteria commonly found in the rhizosphere, the zone near plant roots that is influenced by plant exudates. The organisms of the rhizosphere compete for the nutrients and for space in this soil environment, and many of them produce antibiotic and anti-fungal compounds as secondary metabolites that inhibit the growth of other microorganisms. The rpoS gene has been found to be necessary for production of some of the antibiotic compounds, as well as being important in the existence of bacteria within biofilms, since the fluctuations of the microenvironments there make oxidative and other metabolic stress a relatively common occurrence.

Research goals include the following:

  • The rpoS gene will be “knocked out” in Chromobacterium violaceum, a soil inhabitant known to produce antibiotic compounds.
  • A gene for the green fluorescent pigment will be inserted behind the rpoS promoter and rpoS transcription will be correlated with antibiotic production.
  • An analysis of secondary metabolites for potential antibiotic and/or antifungal activity will be conducted in collaboration with the laboratories at the Cochran Research Center.