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Biomedical subjects

K Shimada

Publications and source records attributed to K Shimada.

At least 1,585 records · Page 88Linked to original sources
PubMed1976

Chemical modification by trinitrobenzenesulfonate of a lipid and proteins of intracytoplasmic membranes isolated from Chromatium vinosum and Azotobacter vinelandii.

1. The structure of intracytoplasmic membranes of a photosynthetic bacterium chromatium vinosum and a nitrogen-fixing bacterium Azotobacter vinelandii was studied by chemical modification of amino groups of phosphatidylethanolamine and proteins with trinitrobenzenesulfonate. 2. Almost all the constituents of intracytoplasmic membranes of C. vinosum were solubilized in a mixture of chloroform, methanol and trichloroacetic acid. One-third of proteins in the intracytoplasmic membranes of C. vinosum was found solubilized in a mixture of chloroform and methanol. By using a column chromatography with Sephadex LH-20 in organic solvents, the unmodified as well as the trinitrophenylated proteins and also the trinitrophenylated phosphatidylethanolamine were separated from the other colored substances. 3. In the chemical modification of the intracytoplasmic membrane preparations, 30% of phosphatidylethanolamine and 15% of protein amino groups in C. vinosum and 45% of phosphatidylethanolamine and 20% of protein amino groups in A. vinelandii were estimated to be exposed to the aqueous phase. In the single-layered liposomes composed of phosphatidylethanolamine and phosphatidylglycerol with a ratio of 2:1, 40% of phosphatidylethanolamine were estimated to be exposed to the aqueous phase.

Amino Acids↗
PubMed1976

Expression of the guanine operon of Escherichia coli as analyzed by bacteriophage lambda induced mutations.

Studies were made on two guanine-requiring strains of Escherichia coli isolated independently as a result of insertion of prophage gamma into one of the structural genes of the guanine operon. These mutants do not exhibit any detectable guaB function but express the guaA function constitutively at a low level, presumably due to transcription from the pI promoter on the prophage. Various types of plaque-forming gua-transducing phages were generated from these lysogens. The approximate location and the mode of substitution of the gua genes in the phage genome were determined. These results clearly indicate that the gene guaB is located closer to the operator-promoter region of the gua operon than is guaA, and the gene order is "operator"-guaB-guaA.

Coliphages↗