Prey-derived signals regulating duration of the developmental growth phase of Bdellovibrio bacteriovorus.
The filamentous elongation typical of growth-phase cells of the predatory bacterium Bdellovibrio bacteriovorus is mediated by regulatory signals that are derived from the prey cell itself. These signals regulate the differentiation of growth-phase cells into the attack phase and appear to be required for continued filamentous growth by prey-dependent wild-type bdellovibrios and their prey-independent mutant derivatives alike. Using a prey-independent bdellovibrio strain, we have developed an assay for the detection and quantification of the growth-extending signal activity present in extracts of prey cells. This prey-derived regulatory activity was shown to be independent of its nutritional contribution to the bdellovibrios and was found to occur in heat-stable, proteinlike compounds of a variety of native molecular weights within the soluble fraction of extracts from both gram-negative and gram-positive bacteria.
Department of Biological Sciences, University of Southern California, Los Angeles 90089.
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D001501:Bdellovibrio / Q000235:genetics / Q000254:growth & development*; D003470:Culture Media; D004269:DNA, Bacterial / Q000096:biosynthesis; D006090:Gram-Negative Bacteria / Q000502:physiology; D006358:Hot Temperature; D007700:Kinetics; D012441:Saccharomyces cerevisiae / Q000502:physiology; D013997:Time Factors
D003470:Culture Media; D004269:DNA, Bacterial