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Biomedical subjects

K Isono

Publications and source records attributed to K Isono.

At least 487 records · Page 27Linked to original sources
PubMed1980

Ribosomal protein modification in Escherichia coli. II. Studies of a mutant lacking the N-terminal acetylation of protein S18.

A mutant of Escherichia coli K12 has been isolated which shows an alteration in the ribosomal protein S18. Genetic analyses have revealed that the mutation causing this alteration maps at 99.3 min of the E. coli genetic map, between dnaC and deo. This indicated that the mutation has occurred in a gene different from the structural gene for this protein which has been located at 94 min. From the N-terminal amino acid sequence analysis it is concluded that the mutation has resulted in loss of the N-terminal acetyl group of this protein. The gene which is affected in this mutant is termed rimI that most likely specifies an enzyme acetylating the N-terminal alanine of protein S18. The mutation does not affect the acetylation of two other ribosomal proteins, S5 and L12, both of which are known to be acetylated in wild-type E. coli K12.

Acetylesterase↗
PubMed1980

Genetic fine structure of the pyrE region containing the genes for ribosomal proteins L28 and L33 in Escherichia coli.

Temperature-sensitive mutants harbouring alterations in ribosomal proteins L28 and L33 have been isolated and used in mapping the genes coding for the two proteins. It was found that they mapped very close to each other and near pyrE at 80.7 min on the E. coli genetic map. The genes affected by the mutations have been concluded to be the structural genes for proteins L28 (rpmB) and L33 (rpmG) by constructing merodiploids heterozygous for pyrE and for the two ribosomal proteins. Various transduction studies with P1kc phages indicate the gene order in this region to be (rpmB, rpmG)-pyrE-spoT-gltC.

Bacterial Proteins↗
PubMed1980

Isolation and characterization of specialized transducing lambda phages carrying ribosomal protein genes of Escherichia coli.

Specialized transducing lambda phages have been isolated which carry the regions of the Escherichia coli chromosome containing the gene or gene-clusters for ribosomal proteins (r-proteins) S1, S6-S18-L9, S16-L19, and L28-L33. To investigate whether these phages also carry the genes for r-proteins S9, L13, L20, L31 and L34 whose gene locations are not known, cells irradiated with UV light were infected with these phages and the r-proteins synthesized were analyzed by two-dimensional gel electrophoresis. However, no synthesis of these r-proteins was stimulated, indicating that their genes are not located in the neighborhood of any of the above-mentioned genes or gene clusters. It was found that proteins S6 and S18 synthesized in the cells irradiated with UV light were not modified under these conditions in which no concomitant ribosome assembly took place.

Bacteriophage lambda↗
PubMed1979

Proximal gastric vagotomy and suprapyloric antrectomy. Experimental evaluation in dogs.

In five dogs with Heidenhain pouches, proximal gastric vagotomy and suprapyloric antrectomy did not alter the rate of gastric emptying of 300 mL of 1% dextrose or of 40 plastic spheres, or disrupt the barricade preventing duodenogastric reflux. However, the operation did slow gastric emptying of 50 g of cubed liver and increase the postprandial secretion of hydrochloric acid from the pouch. We concluded that suprapyloric antrectomy can be combined with proximal gastric vagotomy without disturbing the gastric emptying of liquids and indigestible solids or resulting in increased duodenogastric reflux. However, the operation does slow gastric emptying of digestible solids.

Animals↗
PubMed1979

The gene for ribosomal protein L25 (rplY) maps at 47.3 min near nalA in Escherichia coli K-12.

A temperature sensitive mutant, termed JE1306, derived from Escherichia coli strain PA3092 was found to have an alteration in the ribosomal protein L25. Crosses with various Hfr strains and transductions with P1 kc phage have revealed that the mutation maps at 47.3 min between nalA and fpk, in a region where no ribosomal protein gene has so far been located. The gene affected by this mutation is most probably the structural gene for protein L25 (rplY), because a strain heteromerozygous for the region shows both wild type and mutant forms of protein L25.

Chromosome Mapping↗