Satimaru Seno

Isolation and characterization of nephritogenic antigen from bovine glomerular basement membrane

A method for isolation of a potent nephritogenic antigen from bovine glomerular basement membrane has been established; the glomerular basement membrane was solubilized by trypsin digestion and fractionated successively by gel filtration on Ultrogel AcA-34, concanavalin A affinity chromatography and affinity chromatography on immobilized antibodies. The antigen thus prepared was found to be highly nephritogenic; it causes glomerulonephritis in rats by a single injection of 0.1 mg per individual. Amino acid and carbohydrate analyses revealed that the antigen is a glycoprotein which contains amino acids and sugars characteristic of collagen, namely, hydroxyproline, hydroxylysine, glycine, glucose and galactose, although the relative amounts of these amino acids and sugars are less than those found in Type IV collagen of glomerular basement membrane.

Changes in structural organization of surface membrane during erythrocyte maturation

The effect of concanavalin A and its succinylated derivative on cell agglutination and potassium compartmentation of mature and immature erythrocytes was observed. The binding of tetravalent concanavalin A to the surface glycoproteins of rabbit erythrocytes leads to a change in the properties of the surface membrane, which results in an induction of cell agglutination and concomitant release of potassium from the cells. Both of the phenomena induced by concanavalin A are temperature dependent, and observed at above 15 degrees C. Divalent succinylated concanavalin A, lacking the inducing activity of surface glycoprotein cross-linking into patches and caps, caused neither cell agglutination nor change in the potassium compartmentation of erythrocytes and reticulocytes. In the case of immature reticulocytes, however, remarkable agglutination of the cells was induced without a change in the potassium compartmentation after treatment with tetravalent concanavalin A. It is suggested that changes in the molecular organization of the surface membrane occur in which potassium compartmentation of the reticulocytes becomes more susceptible to surface glycoprotein cross-linking during cellular maturation.

Hemopoietic Recovery in Bone Marrow of Lethally Irradiated Rats Following Parabiosis

Aplasia was induced in rats by total body irradiation. Three days later, the animal was conjugated by aortic anastomoses with a healthy untreated litter-mate. 6 h after parabiosis, the bone marrow of irradiated animals contained some granulocytes showing RNA synthesis. At 18 h, many myelocytes and promyelocytes were present but no myeloblast was encountered. These myeloid precursor cells showed active DNA synthesis but no mitoses, and no erythroblasts were observed at this time period. At 24 h, mitoses of myeloblasts were found. At 42--60 h, erythropoiesis was evident. Chromosome analysis and investigations of cells of irradiated parabionts conjugated with partners having labeled cells, revealed that these newly formed myeloid and erythroid cells originated from the untreated parabiont. The mechanism of triggering myelopoiesis in the aplastic bone marrow by parabiosis is discussed.

Mitochondrial metabolism in porphyric rat liver

Abstract The metabolism of the mitochondria (porphyric mitochondria) isolated from the porphyric livers of rats whose porphyrin synthesis has been stimulated by administration of allylisopropylacetamide was studied and compared with the metabolism of normal mitochondria. Polarographic analysis of the porphyric mitochondria showed a lowered respiratory control with an enhanced rate of the State 4 respiration and no changes in ADP/O ratios. The disturbance of respiration was specifically located in the NAD-linked substrate oxidation; succinate oxidation was far less affected. The porphyric mitochondria showed slightly enhanced Mg2+- and dinitrophenol-dependent latent ATPase activities and also higher ratios of cytochrome c + c1 relative to mitochondrial cytochromes, a and b. Similar respiratory disturbances could be induced in vitro in normal mitochondria by adding δ-aminolevulinic acid.

Regulation of tumor growth as a ‘total mass' in mice: Apoptosis as a major mechanism in altering growth rates of single and multiple coexisting tumor nodules

Earlier studies have suggested that a did tumor behaves, In Its general pattern of growth, like a normal Integrated organ. In this study, the growth patterns of spherically shaped tumor nodules are re‐examlned using an accurate tumor volumemeasuring procedure, with the aim of lnveetlgattng the possible role of apoptosis in regulating tumor growth. Observations revealed at least three distinct phases at growth: rapid growth phase I, slower growth phase II and ‘stationary’ phase III. Transkion from one phase to the next was primarily due to an increase in the level of apoptosis and not to a decrease in the cell proliferation rate. The level of apoptosis, at a given phase, was similar in a single nodule and each of the multiple coexisting nodules of the same tumor line. However, temporal shifts in apoptosis levds caused early phase transition in coexisting nodules, such that their total volume was the same as that of a single nodule. it can be concluded that apoptasls appears to be a primary mechanism regulating tumor growth as a ‘total mass’, irrespective of whether the tumor exists in one or multiple nodules, if derived from the same tumor line.

Importance of antigen-lymphocyte interaction in establishment of cellular immunity

Abstract For the purpose to observe the effect of direct interaction of antigen with lymphocyte on the establishment of cellular immunity, immunization tests were made on mice with the formol-fixed Ehrlich ascites tumor cells and MH 134 hepatoma cells. The cells were fixed without any severe deformation of their surface antigen by treating with dilute formol solution at a low temperature. The fixed cells had negative surface charge and failed to associate with lymphocytes. They were poor in immunogenic capacity, though they had well-kept surface antigen. By treating with poly- l -lysine their negative surface charge turned to positive without impairing their surface antigen. The cells became to adhere to lymphocytes and acquired an extremely high immunogenic capacity.

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Die Chironomiden stellen ein bevorzugtes cytologisches Untersuchungsobjekt dar. Besonders die Riesenchromosomen in den Speicheldrusen sind hochpolytan und konnen in ihrer Struktur sehr gut sichtbar gemacht werden. Wie Mechelke nachwies, bilden die Riesenchromosomen in den drei Lappen der Speicheldrusen von Acricotopus ein unterschiedliches Strukturmuster aus, das durch Anschwellen einzelner Querscheiben oder Querscheibenkomplexe entsteht. In diesen aufgeblahten Querscheiben, den sog. Puffs und BalbianiRingen wird verstarkt RNS synthetisiert. In Analogie zu dem unterschiedlichen Struktur-muster der Riesenchromosomen in den einzelnen Speicheldrusenlappen liesen sich chemische Unterschiede zwischen den Drusenlappen feststellen. In Haupt- und Nebenlappen der Speicheldrusen wurde Hydroxyprolin nachgewiesen; es wird hier wahrscheinlich synthetisiert. Dagegen konnte in dem Vorderlappen diese Aminosaure nicht gefunden werden. Hydroxyprolin kommt weder im restlichen Tierkorper noch in der Nahrung vor. Versuche mit 14C-Prolin sollten nun zeigen, ob Puffs oder Balbiani-Ringen im Haupt- und Nebenlappen der Speicheldrusen eine direkte Beteiligung bei der Hydroxyprolinsynthese zukommt. Die Autoradiographien der mit 14C-Prolin inkubierten Speicheldrusen ergaben aber keine spezifische Anreicherung der Aktivitat an irgendeiner Stelle der Riesenchromosomen. Wie bei einer Verabreichung anderer aktiver Aminosauren findet sich auch bei einer Verfutterung von 14C-Prolin die Aktivitat im Zellplasma und besonders in dem Sekret der Drusenzellen.

Accumulation of hypoxanthine in reticulocytes affected by 2,4-dinitrophenol and antimycin A

Abstract 1. 1. Reticulocyte maturation is accompanied by the decomposition of ribonucleic acid, decrease in adenosine-5′-triphosphate content with a reduction in the rate of oxidative phosphorylation, and the accumulation of nucleosides and free bases, especially hypoxanthine. 2. 2. In the presence of 2,4-dinitrophenol or antimycin A the reticulocyte maturation is inhibited with the suppression of ribonucleic acid degradation and an enormous increase in nucleosides and bases, mainly hypoxanthine. 3. 3. It is suggested that the accumulation of nucleosides and bases, including hypoxanthine, seen in the course of maturation originates mainly from the degradation of high-energy phosphorus compounds rather than that of ribonucleic acid.

Hemoglobin Synthesis in Erythroid Cells A Morphologic and Cytochemical Study

The mammalian red cells pass through two evolutional changes during their ripening processes. The first one is the shift of cytoplasm from the basophilic to the acidophilic state, that means the progress of hemoglobin synthesis. The second one is the denucleation by which cells are flattened and facilitated in enhancing the efficiency of oxygenation of hemoglobin. In this report I will describe the analytical results on the hemoglobin synthesis in erythroid cells, especially relating to the morphologic and cytochemical evolution of the organellae.

An optimum dose of c-H-ras is a prerequisite for hormone-dependent conversion of a cell between cancerous and normal states in tissue culture

We have established a few cell lines which can be reversibly converted from cancerous to normal and vice versa by the addition to, or removal from the culture medium of glucocorticoid hormone. These cell lines were derived from mouse NIH 3T3 cells and possessed the integrated gene pairs on chromosomes, which are composed of human mutated c-H-ras fused with mouse mammary tumour virus long terminal repeat and E. coli xanthine-guanine phosphoribosyltransferase gene with the SV40 promoter. We have characterised these cell lines in order to elucidate an essential requirement for the conversion of the state of a cell. It was found that the presence of at least two to three copies of the gene pair per diploid genome are essential. An approximate threshold level of c-H-ras 1.6 kb RNA required for reversible conversion was estimated.