title: [Isolation of Serratia marcescens mutants superproducers of endonuclease by exposure to nitrosomethylurea in a synchronized culture].
abstract: The work was aimed at studying the capability of chemical mutagens, such as hydroxylamine (HA), dimethyl sulfate (DMS) and nitrosomethylurea (NMU), to produce mutants of Serratia marcescens with an elevated synthesis of endonuclease. HA and DMS did not induce these mutations at tested concentrations. NMU caused such mutations resulting in a sharp rise of endonuclease production. The mutagen was added to the medium at different periods of synchronized DNA replication to generate a selective effect on certain genes located in the replication sites. A 15-minute period 40 min after the beginning of the lag-phase was shown to be most sensitive to NMU treatment for producing mutants with a high yield of endonuclease. A mutant of S. marcescens was obtained, which synthesized endonuclease 40-100 times as effective as the parent strain did. The ability of S. marcescens endonuclease to hydrolyze RNA and DNA and to inhibit the reproduction of RNA- and DNA-containing viruses is of practical importance.
mesh_terms: D001431:Bacteriological Techniques; D002999:Clone Cells / Q000187:drug effects / Q000201:enzymology; D004720:Endonucleases / Q000096:biosynthesis*; D006898:Hydroxylamines / Q000494:pharmacology; D008770:Methylnitrosourea / Q000494:pharmacology*; D009153:Mutagens / Q000494:pharmacology; D009154:Mutation; D009607:Nitrosourea Compounds / Q000494:pharmacology*; D012706:Serratia marcescens / Q000187:drug effects / Q000201:enzymology / Q000302:isolation & purification*; D013463:Sulfuric Acid Esters / Q000494:pharmacology; D013997:Time Factors
chemical_list: D006898:Hydroxylamines; D009153:Mutagens; D009607:Nitrosourea Compounds; D013463:Sulfuric Acid Esters; D008770:Methylnitrosourea; D004720:Endonucleases; C007482:dimethyl sulfate
vernacular_title: Poluchenie mutantov Serratia marcescens superprodutsentov éndonukleazy putem vozdeĭstviia nitrozometilmochevinoĭ na sinkhronizirovannuiu kul'turu.