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Biomedical subjects

Y Ohba

Publications and source records attributed to Y Ohba.

At least 253 records · Page 14Linked to original sources
PubMed1984

Phosphorylation of H1 subtypes in regenerating rat liver.

H1 histone of rat liver consists of four molecular species designated as H1-1, -2, -3, -4. After partial hepatectomy, phosphorylation of H1-3 was induced first, occurring even within 15 h after the operation. By partial hepatectomy, the rate of incorporation of [3H]lysine into H1 histone increased an average of 4-5 times, but that into H1-4 increased 16-20 times. This actively synthesized H1-4 was subsequently degraded rapidly. Thus induction of this active turnover of H1-4 seems to be correlated with liver regeneration. The maximum activity for phosphorylation of H1-3 attained in regenerating liver was five times that in normal liver. By 36 h after the operation, the phosphorylated peak in the chromatographic pattern had moved forward to a position between the peaks of H1-2 and H1-3, named H1-3'. The newly synthesized H1-3 was not transferred appreciably to H1-3' within 30 h after the operation. At 48 h after the operation, H1-3' amounted to 40% of the total H1-3 subtype. The specificity of the phosphorylation reaction was examined in a reaction system consisting of isolated H1 histone and cAMP-dependent kinase. It was concluded that the specificity of the phosphorylation reaction in vivo was due mainly to the difference in structures of different H1 subtypes.

Animals↗
PubMed1984

HB F-Yamaguchi (gamma 75Thr, gamma 80Asn, gamma 136Ala) is associated with G gamma-thalassemia.

Restriction endonuclease and analyses of DNA from a known Hb F-Yamaguchi heterozygote and three of his relatives have shown a deletion of about 5 kb, which includes one of the gamma genes. This abnormality is similar to the G gamma-thalassemia described recently [4] and is probably caused by an unequal crossing over between-G gamma- and -A gamma T-genes. The abnormal-G gamma A gamma T-X-(X = Asp leads to Asn at gamma 80) hybrid gene produces the gamma-Yamaguchi chain at a level usually seen for G gamma chains only.

Child, Preschool↗
PubMed1983

Electron--nuclear-double-resonance studies of spinach plastocyanin.

Electron--nuclear-double-resonance (ENDOR) studies of spinach plastocyanin revealed that 14N-hyperfine couplings from its two co-ordinated imidazole groups are characteristically small in anisotropy and relatively high in ENDOR frequencies and that the two imidazole groups are magnetically equivalent. The relatively strong copper-imidazole co-ordinate bonds of plastocyanin are interpreted to be a result of the coexistence of a strong copper--thiol co-ordinate bond.

Binding Sites↗
PubMed1983

Artificial structure of chromatin derived in the preparation process.

Nuclei were isolated from mouse lymphoma L5178Y cells in the exponential growth phase, and chromatin was prepared by mechanical treatment of the nuclei. The nuclei and the chromatin were then digested to various extents with micrococcal nuclease and the resulting mono- and dinucleosome fractions of the two preparations were compared. During progressive digestion mononucleosomes from chromatin retained H1 histone and a DNA length of 165 base pairs, whereas those from nuclei released H1 histone and the length of their DNA decreased to 140 base pairs at an early stage of digestion. These nucleosomal preparations were always associated with nonhistone proteins. The dinucleosomes from nuclei contained larger amounts of nonhistone proteins than those from chromatin, but half of these proteins was released during the process of cleavage into mononucleosomes. The final mononucleosome preparation from nuclei retained 20% less nonhistone proteins than that from chromatin. The contents of nonhistone proteins in mono- and dinucleosomes from chromatin were the same. The electrophoretical distributions of molecular species of nonhistone proteins in mononucleosomes from nuclei and chromatin were different from each other: during digestion the profile of the former changed, whereas that of the latter remained constant. It is tentatively concluded that both H1 histone and nonhistone proteins were bound to nucleosomes more or less loosely in intact nuclei in situ, but that when the nuclear structure was disrupted these proteins became more tightly bound.

Animals↗
PubMed1983

A case of juvenile erythroleukemia with uncoordinated expression of fetal red cell markers.

A 7-year-old boy with juvenile erythroleukemia is described, whose red cells demonstrated a high content of Hb F with fetal structure and yet contained carbonic anhydrase at adult red cell level. The findings seem to exemplify the occurrence of uncoordinated expression of fetal markers and consequently the incomplete reversion to fetal-type erythropoiesis in a hematologic malignancy.

Carbonic Anhydrases↗
PubMed1983

Hemoglobin saitama or beta 117 (G19) His leads to Pro, a new variant causing hemolytic disease.

An electrophoretically silent unstable hemoglobin was found in a 23-year-old Japanese woman suffering from hemolytic anemia and jaundice. The unstable beta subunit was precipitated with p-chloromercuribenzoic acid and the globin was further purified by urea CM-52 column chromatography. Results of amino acid analysis, tryptic fingerprinting and manual Edman degradation of the abnormal beta T12B established a substitution of proline for histidine beta 117 (G19). This new abnormal hemoglobin was absent in other members of the family.

Adult↗