Membrane damage and incorporation of Escherichia coli components into Bdellovibrio bacteriovorus

Cytoplasmic membrane of E. coli is degraded within 20 min following infection with Bdellovibrio. 50% of cellular 42-K is lost during the first 10 min. The cytoplasmic membrane, 20 min after infection, centrifugated on a sucrose gradient produces a wide band containing the main enzyme activities (succinic dehydrogenase and lactic dehydrogenase) bound to the membrane. The incorporation into Bdellovibrio of labelled host cell constituents during intracellular growth has been studied at successive intervals during the development cycle in diluted nutrient broth (about 3 hrs). The cells were broken in a Sorvall-Ribi cell fractionator and the Bdellovibrios separated by centrifugation on sucrose gradient. Polysaccharides, proteins and lipids of Bdellovibrio derive from the utilization of components of the host cells and not from the utilization of the components present in the medium. The incorporation of precursors into polysaccharides and proteins shows the same exponential pattern.