RESPONSES TO NUTRIENT STARVATION IN PSEUDOMONAS-PUTIDA KT2442 - 2-DIMENSIONAL ELECTROPHORETIC ANALYSIS OF STARVATION-INDUCED AND STRESS-INDUCED PROTEINS

The responses of Pseudomonas putida KT2442 to various forms of nutrien t starvation and stress conditions were examined by two-dimensional po lyacrylamide electrophoresis. Carbon deprivation resulted in a tempora l expression of two classes of starvation-induced proteins: one class was transiently expressed during the initial phase of starvation, and the second class was expressed throughout the entire starvation period . Proteins of the second class could be further subdivided into protei ns induced specifically under conditions of carbon starvation, protein s also induced by conditions of stress created by elevated temperature and osmolarity, and finally proteins that were also induced by condit ions of nitrogen as well as phosphate starvation. Addition of glucose to a carbon-starved culture led to initiation of a recovery phase. Dur ing this phase, repression of starvation-induced proteins as well as i nduction of a new class of transiently expressed proteins, referred to as maturation proteins, took place.