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Biomedical subjects

Y Mitsui

Publications and source records attributed to Y Mitsui.

At least 361 records · Page 20Linked to original sources
PubMed1978

Crystallization of arginine-, formylmethionine-tyrosine-, and glycine-transfer RNAs from Escherichia coli.

Crystals as large as 0.5 X 0.3 X 0.2 mm of purified arginine-transfer RNA from Escherichia coli have been prepared by a vapour diffusion method. X-ray diffraction photographs showed that the crystals gave reflections up to 3.7 A spacing. They have a trigonal space group P31 2 1 (OR P32 2 1) and cell-dimensions a=97.2, b=97.2, c=94.8A. Crystals of a mercury derivative of this transfer RNA have also been obtained, and an X-ray diffusion photography of one of them is presented. Formylmethionine-transfer RNA from E. coli was crystallized in various forms, and the appearance of the polymorphs was found to depend upon the amount of spermine in the solution from which the crystallization took place. Crystals of tyrosine-transfer RNA and glycine-transfer RNA have also been obtained.

Arginine↗
PubMed1978

Crystal structure of a protein proteinase inhibitor, SSI (Streptomyces subtilisin inhibitor), at 4 A resolution.

The crystal structure of a protein proteinase inhibitor, SSI (Streptomyces subtilisin inhibitor), which strongly inhibits bacterial alkaline proteinases specifically, was determined at 4 A resolution using four heavy-atom derivatives. The SSI molecule can be described as an ellipsoid of about 30 X 40 X 65 A composed of two identical subunits each having dimensions of about 35 X 25 X 40 A and a molecular weight of 11,483. The subunit has an extensive beta-sheet structure, but no long alpha-helices are present. Based on the binding sites of platinum reagents known to form coordination complexes with methionine, it is speculated that the P1 residue, Met 73, of the reactive site is at the protruding edge of the subunit. At the subunit-subunit interface, a beta-sheet of one subunit is stacked on top of the corresponding beta-sheet of the other subunit.

Bacterial Proteins↗
PubMed1977

Crystal structure of a protein proteinase inhibitor, Streptomyces subtilisin inhibitor, at 2.3 angstrom resolution.

The crystal structure of a protein proteinase inhibitor, Streptomyces subtilisin inhibitor which strongly inhibits bacterial alkaline proteinases, was determined at 2.3 angstrom resolution. The subunit (molecular weight, 11,485) of this dimeric molecule has a unique fold of polypeptide chain with a five-fold anti-parallel beta-sheet structure (about 21% of the 113 amino acid residues) and two small segments of alpha-helices (about 16%). The region around the apparent reactive site, Met(73)-Val(74), is held tight by a combination of various structural features. The conformation of this region seems to have close similarity to that found in substrate analogues of low molecular weight bound to subtilisin BPN'.

Crystallography↗
PubMed1976

Crystallization and preliminary crystal data of iron-containing superoxide dismutase from Pseudomonas ovalis.

Large single crystals of iron-containing superoxide dismutase from Pseudomonas ovalis were prepared from 50% saturated ammonium sulfate solution, at pH 4.5, on gentle evaporation of the solvent at 4 degrees. The crystals were monoclinic, space group P2, with unit cell dimensions a = 81.9 A, b = 49.0 A, c = 61.0 A, and beta = 106 degrees. Considerations of cell volume and protein molecular weight indicated 1 molecule of superoxide dismutase in the assymmetric unit, the smallest number reported so far for superoxide dismutases.

Binding Sites↗
PubMed1976

The relationship between in vitro cellular aging and in vivo human age.

Differences between early and late passage cell cultures on the organelle and macromolecular levels have been attributed to cellular "aging". However, concern has been expressed over whether changes in diploid cell populations after serial passage in vitro accurately reflect human cellular aging in vivo. Studies were therefore undertaken to determine if significant differences would be observed in the in vitro lifespans of skin fibroblast cultures from old and young normal, non-hospitalized volunteers and to examine if parameters that change with in vitro "aging" are altered as a function of age in vivo. Statistically signigificant (P less than 0.05) decreases were found in the rate of fibroblast migration, onset of cell culture senescence, in vitro lifespan, cell population replication rate, and cell number at confluency of fibroblast cultures derived from the old donor group when compared to parallel cultures from young donors. No significant differences were observed in modal cell volumes and cellular macromolecular contents. The differences observed in cell cultures from old and young donors were quantitatively and qualitatively distinct from those cellular alterations observed in early and late passage WI-38 cells (in vitro "aging"). Therefore, although early and late passage cultures of human diploid cells may provide an important cell system for examining loss of replicative potential, fibroblast cultures derived from old and young human donors may be a more appropriate model system for studying human cellular aging.

Aging↗
PubMed1976

Deposits of mucosubstances on the cornea by topical chloramphenicol: an electron microscopic study.

Chloramphenicol was instilled into rabbit eyes and five days later the corneal surface was examined by scanning electron microscopy. The corneal surface was roughened and showed a proliferative appearance. Examination of thin sections of the cornea by transmission electron microscope showed that the corneal surface stained strongly with alcian blue. It was thus supposed to be a deposit of mucosubstances. Mucosubstances increase pathogenicity of bacteria and, therefore, this deposit may accelerate Pseudomonas keratitis after chloramphenicol application.

Animals↗
PubMed1976

The role of mucin on experimental Pseudomonas keratitis in rabbits.

The role of mucin in the manifestation of Pseudomonas keratitis was studied. Pseudomonas was cultivated in solutions of mucin, in which it grew rapidly and then inoculated into rabbit cornea by needle pricks. When the organism was inoculated as a suspension in saline, infection infrequently occurred as small ring abscesses of short duration around a few sites of inoculation. When the organism was inoculated as a suspension in a solution of gastric mucin, infection was usually observed as severe hypopyon-keratitis with formation of a huge ring abscess. Corneal perforation and panophthalmitis resulted in some cases. It was thus concluded that the pathogenicity of Pseudomonas is definitely increased when it was inoculated into the cornea with mucin solution.

Abscess↗