Biomedical subjects

Y Komeda

Publications and source records attributed to Y Komeda.

75 records · Page 5Linked to original sources

PubMed1977

Genetic analysis of Escherichia coli K-12 region I flagellar mutants.

Flagellar mutants in Escherichia coli region I were obtained by selection for resistance to the flagellotropic phage chi. F' elements carrying this region of the E. coli genome were then constructed. Stable merodiploid strains with a flagellar defect on the exogenate and another on the endogenote were prepared. These merodiploids yielded information on the complementation behavior of mutations in this region. Region I was shown to include at least six cistrons, flaV, flaK, flaL, flaM, flaS, and flaT. Mu-induced and deletion fla mutants were also isolated. By using these mutant strains, the transcriptional order was shown to be flaV-flaK-flaL-flaM-flaS-flaT. The definition of region I fla genes and their transcriptional relationships were confirmed by genetic tests with hybrid A phage carrying fla genes in this region.

Chromosome Mapping↗

PubMed1977

Isolation of specialized lambda transducing bacteriophages for flagellar genes (fla) of Escherichia coli K-12.

Specialized transducing lambda phages carrying the region III flagellar genes (fla) of Escherichia coli K-12 were isolated by a new method. A strain carrying both a cryptic lambda prophage near the his genes and a deletion of the attlambda gene was used as a starting strain. The lysogen of lambdacI857pga18-bio69 was isolated in which the prophage was integrated within the lambda cryptic genes by means of recombination with the residual lambda DNA. The strains with deletions starting within the prophage and ending in these fla genes were selected from among the heat-resistant survivors of the lysogen. They were then infected with heat-inducible and lysis-defective lambda phages and, thus, specialized transducing phage lines for hag and fla were obtained. High-frequency transfer lines of rare phages carrying the fla genes were isolated by inducing a strain carrying a heat-inducible lambda prophage near the his genes and selecting by transduction of a fla deletion strain. Preliminary characterization of these transducing phages is also reported.

Chromosome Mapping↗

PubMed1976

The role of cAMP in flagellation of Salmonella typhimurium.

A mutational alteration either in adenylate cyclase (cya-) or in cyclic-3'5'-AMP (cAMP) receptor protein (crp-) rendered Salmonella typhimurium incapable of producing flagella. The amount of mRNA specific for flagellin in these mutants was almost negligible when assayed in an in vitro protein synthesizing system. A secondary mutation cfs, partially suppressing the cya- mutation, was identified among the revertants of cya-. A mutation in the same cistron as cfs resulted in a non-flagellate phenotype either by itself or in combination with cfs. The cistron, which was given the gene symbol flaT, was located between flaE and flaL. It was suggested that cAMP receptor protein together with cAMP modulates the gene flaT, which in turn acts as a positive effector on the synthesis of active mRNA specific for flagellin.

Adenylyl Cyclases↗