title: Isolation and properties of a ribonuclease-deficient mutant of Salmonella typhimurium.
abstract: A mutant of Salmonella typhimurium has been isolated that has less than 5% of the ribonuclease activity of the parent strain. Mutant screening and enzyme assays were done in the presence of ethylenediaminetetraacetic acid, a substance that activates ribonuclease I and inhibits other known microbial nucleases. Genetic mapping indicates that the mutation is located between the purE and gal genes on the Salmonella chromosome. A ribonuclease-deficient mutant that carries a deletion in the pyrF gene is unable to utilize ribonucleic acid as a pyrimidine source, whereas the pyrF parent with normal ribonuclease activity will grow. This suggests that the enzyme may perform a scavenge function in the utilization of exogenous ribonucleic acid. Loss of this enzyme seems to have no detrimental effects on the growth of Salmonella.
mesh_terms: D002874:Chromosome Mapping; D003454:Cryptococcus; D003470:Culture Media; D004492:Edetic Acid / Q000494:pharmacology; D005796:Genes; D009154:Mutation; D009604:Nitrosoguanidines / Q000494:pharmacology; D012313:RNA / Q000378:metabolism; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D011995:Recombination, Genetic; D012260:Ribonucleases / Q000378:metabolism*; D012486:Salmonella typhimurium / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D013268:Stimulation, Chemical; D014161:Transduction, Genetic
chemical_list: D003470:Culture Media; D009604:Nitrosoguanidines; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D012313:RNA; D004492:Edetic Acid; D012260:Ribonucleases