Jörgen Östling

How do non-differentiating bacteria adapt to starvation?

Non-differentiating bacteria adapt to starvation induced growth arrest by a complex turn-on/turn-off pattern of protein synthesis. This response shows distinct similarities with those of spore formation in differentiating organisms. A substantial amount of information on the non-growth biology of non-differentiating bacteria can be derived from studies onVibrio strains. One important result is that carbon rather than nitrogen or phosphorus starvation leads to the development of a starvation and stress resistant cell in these organisms. Hence, we have attempted to characterize the carbon starvation stimulon. By the use of two-dimensional gel electrophoresis of pulse-labelled cells and transposon mutagenesis, using reporter gene constructs, the identity and function of some members of the carbon starvation stimulon have been elucidated. Moreover, regulatory genes of the starvation response have been identified with these techniques. Current studies primarily address the identity and function of these genes. The role of transcript modification and stability for both long term persistence during starvation as well as the efficient recovery of cells which occurs upon nutrient addition is also addressed. It is suggested that an understanding of the functionality of the translational machinery is essential for the understanding of these adaptive pathways. This contribution also discusses the diversity of the differentiation-like response to starvation in different bacteria and whether a general starvation induced programme exists.

Starvation and Recovery of Vibrio

Vibrio species are generally found in the cultivable fraction of marine bacteria. Their coexistence with the dominant pool of oligobacteria in carbon-limited marine waters (Button et al., 1993) as well as their frequent appearance in association with higher organisms (see below) imply a successful life cycle of feast and famine. This chapter presents data on the emerging pattern of an elaborate starvation-induced “differentiation-like programme” in marine Vibrio species, the inducing conditions of this response and its specific, nongrowth-associated physiology, and the routes to successful persistence as well as recovery of the starved ultramicrocell.