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Biomedical subjects

Y Mano

Publications and source records attributed to Y Mano.

At least 181 records · Page 10Linked to original sources
PubMed1977

Accumulation of immunoglobulin messenger ribonucleic acid in immunized mouse spleen.

We have measured the concentration of mRNAs coding for immunoglobulins, k and lambda type light chains and gamma 1 type heavy chain, in mouse spleen cells activated by bacterial lipopolysaccharide or sheep red blood cells. These mRNAs were quantitated by hybridization to radioactive DNA complementary to highly purified immunoglobulin mRNAs from mouse myelomas. In the lipopolysaccharide-stimulated spleen cells, only light chain mRNA accumulated, whereas gamma 1 type heavy chain mRNA remained unvaried. The light chain mRNA concentration also increased in purified bone-marrow-derived lymphocytes. The lipopolysaccharide-induced light chain mRNA was similar to light chain mRNAs purified from myelomas. The accumulation and disappearance of light chain mRNA in bone-marrow-derived lymphocytes coincide with the kinetics of synthesis of immunoglobulin M which is the major species induced by lipopolysaccharide. In sheep red blood cell stimulated spleen, the specific accumulation of k type light chain and gamma 1 type heavy chain mRNAs parallels immunoglobulin G synthesis. These results seem to indicate that the increment of immunoglobulin mRNA concentration in bone-marrow-derived lymphocytes is important for induction of immunoglobulin synthesis.

Animals↗
PubMed1977

Stimulation of sea urchin DNA polymerase by protein factors. II. Formation of active complex in DNA polymerase reaction.

A protein factor, SF I, which stimulated DNA polymerase activity severalfold was purified from nuclei of sea urchin embryos by phase separation, ammonium sulfate fractionation, DNA-cellulose, CM-cellulose and hydroxyapatitecolumn chromatography and gel filtration. The molecular weight of SF I was about 220 000, the S20,W value was about 8.5 and the isoelectric point was determined to be pH 5.1. In the presence of SF I,V of the DNA-polymerizing reaction was increased and Km values for the substrates of this reaction were not changed. Addition of polyamines increased the rate of stimulation. ATP which was required for stimulation could be substituted by other ribonucleoside triphosphates. SF I, nuclear DNA polymerase and ATP seemed to form an active complex, and in the complex, ATP was found to have been converted to AMP and inorganic pyrophosphate.

Animals↗
PubMed1977

Sites of action of the KCl-soluble protein in the stimulation of protein synthesis in sea urchin systems.

The sites of action of the KCl-soluble protein (KSP) in the stimulation of amino acid incorporation were studied with cell-free systems from sea urchin embryos. The reduced form of KSP stimulated amino acid- and tRNA-dependent AMP exchange in the amino acid activation and initiation steps. Stimulation of the binding of phenylalanyl-tRNA (Phe-tRNA) to 40 S ribosomes by KSP was found; the reaction was considered to be the binding to the donor site of ribosomes, based on the results of puromycin treatment, so this stimulation is assumed to occur at the initiation step. All other steps of amino acid-dependent exchange of PPi and ATP as well as hydroxamate formation, amino acid acceptor activity of tRNA, the binding of aminoacyl-tRNA, mRNA, and synthetic polynucleotide to ribosomes, translocation and peptide bond formation, and the termination and release of peptides from ribosomes, were apparently insensitive to KSP. Cyclic variation was observed in the activities of amino acid- and tRNA-dependent AMP exchange with ATP and the binding of aminoacyl (acylated and nonacylated)t-RNA to ribosomes using 12,000 x g supernatant. The reduced form of KSP itself had AMP exhange activity in amino acid activation. The reaction involved was confirmed to be aminoacyl transfer from aminoacyl-AMP to tRNA. However, low activities were observed for the bindings of Phe-and acetylphenylalanyl (AcPhe)-tRNA to ribosomes. Small molecular SH-reagents reacted in a different way from reduced KSP both in the AMP exchange reaction and the binding of aminoacy1-tRNA to ribosomes.

Adenosine Monophosphate↗
PubMed1977

DNA polymerase-beta from the nuclear fraction of sea urchin embryos: characterization of the purified enzyme.

Approximately 2,500-fold purifications of DNA polymerase-beta from the nuclear fraction of blastulae of the sea urchin, Hemicentrotus pulcherrimus, was performed. The enzyme preparation, which was devoid of DNase and terminal deoxynucleotidyl transferase as contaminants, showed a sedimentation constant of 3.0 S in a sucrose density gradient, a molecular weight of 50,000 by gel filtration, and an isoelectric point of pH 8.1. The enzyme activity was resistant to sulfhydryl group inhibitors. Its optimal pH was 9.0-9.5 in Tris-maleate buffer and 10.0 in glycine buffer. The optimal NaCl concentration for the activity was 30-60 mM and about half of the activity remained at 0.4 M NaCl. As a template-primer, the enzyme preferred synthetic homopolymers to activated DNA. The order of this preference was as follows; poly (dA)-oligo (dT)12-18 greater than poly (rA)-oligo (dT)12-18 greater than activated DNA. The above results indicate that the enzyme corresponds to DNA polymerase-beta from vertebrate cells.

Animals↗
PubMed1976

Synthesis of the acid-soluble proteins in early cleaving embryos of the sea urchin. Cyclic synthesis of histones.

Synthesis of the acid-soluble proteins in the early cleavage stage of the sea urichin, Hemicentrotus pulcherrimus, was investigated. As detected by the incorporation of lysine, the acid-soluble proteins were synthesized periodically even before the first cleavage, differing from the pattern of incorporation of tryptophan into the fraction. Cyclic synthesis occurred almost in parallel with DNA synthesis. However, the phase and periodicity of cyclic synthesis of the acid-soluble protein fraction were quite different from those found in the hot TCA-insoluble (acid-insoluble) protein fraction. The acid-soluble proteins were adsorbed on cation exchange resin, Amberlite CG-50, and gave an elution profile similar to that found for calf thymus histones. The migration pattern of these proteins on acrylamide gel also resembled that of histones.

Animals↗
PubMed1976

A cytoplasmic inhibitor of DNA polymerase from the plasmodia of Physarum polycephalum.

A factor which inhibited DNA polymerase [EC 2.7.7.7] activity was isolated from the cytoplasm of plasmodia of true slime mold, Physarum polycephalum. This factor was purified by DEAE-Sephadex and CM-cellulose column chromatographies, heat treatment and gel filtration. This inhibitor was heat-stable, insensitive to trypsin [EC 3.4.21.4] and was not digested by RNase [EC 3.1.4.22] or DNase [EC 3.1.4.5]. The molecular weight was 16,000 as determined by gel filtration, and the isoelectric point was determined to be pH 10.1. In the presence of the inhibitor, Km for DNA in the DNA polymerizing reaction was markedly increased. The inhibitory effect was eliminated by addition of excess DNA, but the addition of excess enzyme or deoxyribonucleoside triphosphates had no effect on the inhibition.

Cytoplasm↗