title: Catabolite-repression-like phenomenon in Rhizobium meliloti.
abstract: We report a phenomenon similar to catabolite repression in Rhizobium meliloti. Succinate, which allows the highest observed rate of growth of R. meliloti, caused an immediate reduction of beta-galactosidase activity when added to cells growing in lactose. A Lac- mutant was unaltered in nodulation and nitrogen fixation capacities, but a pleiotropic mutant deficient in several catabolic properties was unable to produce effective nitrogen-fixing nodules.
mesh_terms: D000242:Cyclic AMP / Q000494:pharmacology; D004794:Enzyme Repression / Q000187:drug effects; D005696:Galactosidases / Q000096:biosynthesis*; D007785:Lactose / Q000378:metabolism; D009586:Nitrogen Fixation; D012231:Rhizobium / Q000378:metabolism*; D013386:Succinates / Q000378:metabolism*; D001616:beta-Galactosidase / Q000096:biosynthesis*
chemical_list: D013386:Succinates; D000242:Cyclic AMP; D005696:Galactosidases; D001616:beta-Galactosidase; D007785:Lactose