title: Isolation and characterization of temperature-sensitive mutants of cyanophage N-1.
abstract: Optimal conditions for the induction of temperature-sensitive (ts) mutants of cyanophage N-1 were established after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). A treatment with MNNG (400 micrograms/ml) for 2 hrs at pH 8.0 induced ts-mutants at a maximum frequency of 1.46 x 10(-3). A characterization of 10 such ts-mutants with regard to adsorption, one-step growth and temperature-shift experiments with Nostoc muscorum as host bacterium led to the identification of temperature-sensitive steps in the phage multiplication at the restrictive temperature (37 degrees C). All the mutants were found to be conditionally lethal at 37 degrees C since they resumed growth upon shifting to 28 degrees C.
authors.affiliation: Department of Botany, Punjabi University, Patiala, India.
authors.forename: T A
authors.initials: TA
authors.lastname: Sarma
authors.forename: R
authors.initials: R
authors.lastname: Singh
mesh_terms: D001435:Bacteriophages / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification; D000458:Cyanobacteria / Q000254:growth & development; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D016296:Mutagenesis; D009154:Mutation; D013696:Temperature
chemical_list: D008769:Methylnitronitrosoguanidine