DETERGENT SENSITIVITY OF RHIZOBIUM BACTEROIDS AND BACTERIA

Mild detergent treatments released 60% of the protein and 30% of the DNA from Rhizobium (strain NZP 2257) bacteroids but did not lyse the bacteroid cell walls. The same treatments had relatively little effect on broth-cultured bacteria. Electron microscopy and zone sedimentation studies, together with assays of cytochrome c oxidase activity, suggested that the effect of detergent was to increase the permeability of the bacteroid cell wall-membrane complex, allowing cytoplasmic components to leach out. Detergent sensitivity developed at the same stage of nodule development as osmotic sensitivity, and bacteroids that required osmotic protection to form colonies were more sensitive to detergent than bacteroids that were able to form colonies on normal media. © 1979.