title: [Ethylmethane sulfonate induction of auxotrophic mutants of Rhizobium meliloti and their characteristics].
abstract: Ethylmethanesulfonate was used as a mutagen to induce auxotrophic mutants in Rhizobium meliloti L5-30. Survival of the culture depended on the period of time during which it was treated with the mutagen. Thirteen auxotrophic mutants were isolated as a result of screening 1404 clones, and their requirements in growtn factors were determined. Ethylmethanesulfonate induced mainly those mutants which required sulfur-containing amino acids. The activity of nitrogen fixation of the auxotrophic mutants was assayed by measuring the reduction of acetylene and the yield of lucerne. Mutants requiring methionine or cystein, cysteine or histidine, and adenine with thiamine were not effective whereas those requiring arginine, tryptophan, and thiamine were capable of nitrogen fixation. Among two methionine auxotrophs, one displayed the activity of nitrogen fixation and the other did not.
mesh_terms: D005020:Ethyl Methanesulfonate / Q000494:pharmacology*; D008698:Mesylates / Q000494:pharmacology*; D009154:Mutation / Q000187:drug effects*; D009586:Nitrogen Fixation / Q000187:drug effects; D012231:Rhizobium / Q000187:drug effects* / Q000378:metabolism; D013559:Symbiosis / Q000187:drug effects; D013997:Time Factors
chemical_list: D008698:Mesylates; D005020:Ethyl Methanesulfonate
vernacular_title: Indutsirovanie étilmetansul'fonatom auksotrofnykh mutantov Rhizobium meliloti i ikh kharakteristika.