title: [Mutants of cyanobacterium Synechocystis sp. PCC6803 with insertion of the sodB gene encoding Fe-superoxide dismutase].
abstract: The sodB gene encoding the only superoxide dismutase (Fe-SOD) in cells of the cyanobacterium Synechocystis sp. PCC6803 was inactivated with gentamycin resistance aacC1 marker insertions located in the direct or inverted order toward the sodB gene. The corresponding delta sodB12 and delta sodB22 mutants are characterized by the complete absence of superoxide dismutase activity and the loss of viability upon standard photoautotrophic cultivation. Mutant cells can grow under conditions of a decreased illumination intensity and upon addition of NaHCO3 with catalase or bovine serum albumin in the growth medium. The delta sodB22 mutant is auxotrophic for leucine due to the polar effect of insertion into the sodB gene on the downstream leuB gene controlling leucine biosynthesis. These data suggest that Fe-SOD is very important for providing tolerance of Synechocystis cells to oxidative stress and that sodB and leuB genes are organized into a single operon.
authors.affiliation: Department of Genetics, Lomonosov Moscow State University, Moscow, 119899 Russia. lidia nefedova@mail.ru
authors.forename: L N
authors.initials: LN
authors.lastname: Nefedova
authors.forename: V A
authors.initials: VA
authors.lastname: Mel'nik
authors.forename: M M
authors.initials: MM
authors.lastname: Babykin
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D003470:Culture Media; D000458:Cyanobacteria / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D004352:Drug Resistance, Microbial; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005804:Genes, Lethal; D005819:Genetic Markers; D005839:Gentamicins / Q000494:pharmacology; D007501:Iron; D007930:Leucine / Q000096:biosynthesis; D016254:Mutagenesis, Insertional; D009154:Mutation; D009876:Operon; D018384:Oxidative Stress; D012710:Serum Albumin, Bovine / Q000378:metabolism; D017693:Sodium Bicarbonate / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D003470:Culture Media; D005819:Genetic Markers; D005839:Gentamicins; D012710:Serum Albumin, Bovine; D017693:Sodium Bicarbonate; D007501:Iron; D002374:Catalase; D013482:Superoxide Dismutase; D007930:Leucine