Survival and intracellular changes of Pseudomonas aeruginosa during prolonged starvation

Abstract

The viability of suspensions of P. aeruginosa, prepared from 48-hr, cultures, grown in either a N-limited or C-limited medium, decreased ?5% during 48-hr, of endogenous respiration, whereas the viable numbers of 48-hr. cells harvested from a complete medium increased 57% during the early stages of endogenous respiration and remained constant thereafter. In all endogenously respiring cell suspensions, RNA and protein decreased by similar amounts and DNA increased. Glucosamine was not found to decrease to a significant degree during starvation. Constitutive enzymes and (or) the cofactors involved in the oxidation of glucose were found to diminish with progressive starvation. Starvation severely depleted the ribosome complement of the cells; however, the starved cells were able to synthesize a permease for o-ketoglutarate. The addition of an exogenous substrate brought about the reincorporation of endogenously liberated NH3 and of 260 m[mu] absorbing material with a concurrent synthesis of 50S ribosomes.