His laboratory studies the responses of cells to high salinity stress. A sudden increase in the external osmolality causes rapid efflux of water from the cells. The ability to adapt to changes in the external osmolality is a fundamental response in cell physiology that is highly conserved across all biological kingdoms. Hisresearch is concentrated on three areas of osmotic regulation. First, the exposure of the food poisoning bacterium Salmonella to moderate or high salinity renders this organism more tolerant of high temperature stress. He is studying the interaction between salinity stress adaptation and high temperature tolerance. This research will provide insights into conditions that increase the efficacy of inactivation of Salmonella in food products by high temperature. He found that proline overproduction confers increased resistance to high salinity stress in Salmonella and other bacteria. The proline-overproducing mutations decreased the sensitivity of g -glutamyl kinase (the first enzyme of proline synthesis) to allosteric inhibition by proline. He is carrying experiments to characterize the enzymological properties and three-dimensional structure the wild type and mutant of g -glutamyl kinases. Better understanding of this enzyme might make it possible to engineer proline overproducing, salt tolerant derivatives of agronomic plants. Finally, he is carrying out physiological and genomic analyses of the bacterium Chromohalobacter salexigens . This bacterium is unusual because it grows optimally in highly saline environments that are lethal to most other organisms. The study of the basis for the exceptional salt stress tolerance of this organism might make it possible to develop it for use in remediation of toxic environments of high salinity.