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Biomedical subjects

H Uchida

Publications and source records attributed to H Uchida.

At least 685 records · Page 38Linked to original sources
PubMed1979

Sigma subunit of Escherichia coli RNA polymerase affects the function of lambda N gene.

A new class of Escherichia coli mutants, referred to as grn, has been isolated by localized mutagenesis. These mutations affect the sigma subunit of DNA-dependent RNA polymerase (ribonucleoside 5'-triphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) by abolishing the expression of the lambda N gene, and they are closely lniked to dnaG in the order dnaG-grn-uxaA. Detailed study of one such mutant, grn1, yielded the following results: (i) grn1 is a single mutation and the mutant cell shows cold-sensitivity in growth; (ii) the Grn phenotype of the mutant can easily be suppressed by secondary mutations in the beta subunit gene of RNA polymerase; (iii) purified holoenzyme of RNA polymerase isolated from the mutant showed an altered salt-dependency in vitro, and the mixed reconstitution of the mutant with the wild-type subunits showed that the sigma subunit of the grn1 mutant is altered; (iv) lambda phage mutants (lambda grg), which overcome the grn mutation, can be classified into two groups, the "nin-deletion" and the "N-mutant" groups (both of these are also able to grow on the previously described groN mutant of Georgopoulos and nusAB of Friedman); (iv) the mutant polymerase transcribed 12S as well as 7S RNA from lambda DNA in the presence of the rho factor in vitro. These results indicate that the grn mutation alters the sigma subunit of RNA polymerase and that the sigma subunit participates in activating the N-mediated antitermination mode of lambda phage transcription.

Bacteriophage lambda↗
PubMed1979

Anastomotic rupture of aortic grafts.

Proximal suture line disruption is one of the severe complications of synthetic vascular grafting for arteriosclerotic aortic disorders. The pathology of clinical and experimental cases revealed that a small bite of each stitch cut into the host aorta and became disrupted. Making each stitch as large as possible in the host aorta is the first procedural choice for aortic replacement surgery. Protecting the anastomotic line with a synthetic mesh cloth wrapping is preferable.

Adult↗
PubMed1979

Effectiveness of a new drug, bredinin, on canine kidney allotransplant survival.

BR has remarkable effectiveness on canine kidney allograft survival. Its effectiveness in suppression of the immune responses is dependent on the dosage. Atrophy of the spleen and the mesenteric lymph nodes is prominent in treated dogs. Septic complications are slight, with no reduction in the number of peripheral white blood cells. Erosive changes of the mucosa in the entire bowel are the major side effects of the drug treatment. Liver functional abnormality has not been observed.

Animals↗
PubMed1979

Lymphographic studies on protein-losing enteropathy.

Lymphographic studies were made on diseases of protein-losing in 19 cases, which include 9 cases of diseases of the digestive canal, 2 cases of constrictive pericarditis, and 8 cases of protein-losing enteropathy. Lymphographically in the diseases of the digestive canal no abnormal findings were detected, but in the constrictive pericarditis remarkable dilation and kinking of the thoracic duct with relatively poor congestion of the lumbar lymphatic vessels were observed. In the intestinal lymphangiectasia dysplasia of the lymphatics, passage disturbance of the thoracic duct with the congestive lumbar lymphatics, reflux to abdominal organs, oozing of contrast medium into the intestinal lumen were disclosed. Also experimentally lymphographic studies in thoracic duct-ligated dogs revealed the reflux to the mesenterial lymphatic system causing protein-losing into the intestine.

Animals↗
PubMed1978

A transducing lambda phage carrying grpE, a bacterial gene necessary for lambda DNA replication, and two ribosomal protein genes, rpsP (S16) and rplS (L19).

A grpE mutation of Escherichia coli K12, which blocks DNA replication of the phage lambda (Saito and Uchida, 1977), was mapped at 56 min on the standard genetic map. A transducing lambda phage, lambdagrpE22, carrying the wild type allele of the grpE gene was constructed in vitro. Structures of lambdagrpE22 and its viable deletion derivatives were determined by electron microscopic analyses of appropriate heteroduplexes. Proteins coded by the bacterial DNA incorporated into the transducing phages were detected by two-dimensional gel electrophoresis. The results showed that the product of the grpE gene is a weakly acidic protein of molecular weight 24,000. Structural genes for two ribosomal proteins, rplS (L19) and rpsP (S16) were also shown to be carried by lambdagrpE22.

Coliphages↗
PubMed1978

Organization and expression of the dnaJ and dnaK genes of Escherichia coli K12.

A temperature-sensitive mutation in the dnaJ gene of Escherichia coli K12 is described which affects replication of the bacterial DNA. The gene is located adjacent to the dnaK gene described previously (Saito and Uchida, 1977). The physical and functional organization of the dnaJ-dnaK region was studied in detail by analyzing the heteroduplexes and functions of various deletion mutants of lambdadnaJdnaK, a transducing phage carrying both of the dna genes. The sizes of dnaJ and dnaK cistrons were estimated to be at most 1.2 +/- 0.5 and 2.1 +/- 0.4 kilobases, respectively. In vivo expression of the dnaJ function by various deletion phages indicated that the dnaK and dnaJ cistrons were transcribed from a promoter located at the head of the dnaK cistron, dnaJ being downstream to dnaK. Presence of a weak promoter which reads only the dnaJ cistron was also suggested. A simple method for isolating independent deletion mutants of phage lambda was described.

Chromosome Mapping↗
PubMed1978

Genetic analysis of two genes, dnaJ and dnaK, necessary for Escherichia coli and bacteriophage lambda DNA replication.

We show that a collection of 93 E. coli mutations which map between thr and leu and which block phage lambda DNA replication define two closely linked cistrons. Work published in the accompanying paper shows that these mutations also affect host DNA replication, so we designate them dnaJ and dnaK; the gene order is thr--dnaK--dnaJ--leu. Demonstration of two cistrons was possible with the isolation of lambda transducing phages carrying one or the other or both of the dna genes. These phages were employed in phage vs bacterial complementation studies which unambiguously show that dnaK and dnaJ are different cistrons.

Coliphages↗