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Biomedical subjects

K Kaji

Publications and source records attributed to K Kaji.

124 records · Page 7Linked to original sources
PubMed1982

Small angle neutron scattering studies of the structure of nucleosome cores at low ionic strength.

Nucleosome core particles from chicken erythrocytes have been studied by small angle neutron scattering over the range from 10 to 0.04 mM Na+ at 65 and 100% D2O, and the radii of gyration of the particle were determined. A single transition in the radius of gyration was observed at either D2O concentration. With decreasing the ionic strength from 10 mM, the radius of gyration of the histones obtained at 65% D2O increased from 35 to 40A at about 1 mM ionic strength, whereas at 100% D2O the radius of gyration decreased from 39 to 36A also near 1 mM ionic strength. No loss of the secondary structure of the histones was observed by circular dichroism over the range of the ionic strength examined. These results suggest that at low ionic strength (less than or equal to 1 mM) the histones may locate outside of the nucleosome core particle accompanied by an alteration of the tertiary and/or the quaternary structure of the histone octamer.

Animals↗
PubMed1980

A low-density inoculation method for the serial subcultivation of human diploid fibroblasts: an efficient model system for the study of cellular ageing.

Human diploid fibroblasts, TIG-1, were serially subcultivated at low inoculation densities thus maintaining the cultures in log phase throughout their in vitro lifespan. Their lifespan was shortened in calendar time without decreasing the cumulative number of population doublings when compared with the lifespan of cells serially cultivated by a standard method of 1:4 splitting. The cytokinetic and morphological changes during their lifespan are quite similar to those of control cells. The frequency of trypsinization doess not influence the cumulative number of population doublings. The "low-denstiy inoculation method" of subcultivation is efficiently and economically advantageous in studying cellular ageing in vitro.

Cell Division↗
PubMed1978

Ageing of chick embryo fibroblasts in vitro. II. Relationship between cell proliferation and increased multinuclear cells.

The cell lines of chick embryo fibroblasts obtained from different embryos were sequentially cultivated and relationship between growth potential and increased multinuclear cells was examined. During ageing in vitro multinuclear cells increased with decreasing growth rate. Their percentage in the senescent cell populations reached 11--15% when the cells stopped growing, and 20--25% just before the cultures died out. This phenomenon may be useful as a parameter for cellular ageing. Most of the multinuclear cells were binucleates. The mean cell volume of the cells also increased through their lifespan with a sharp rise at the latest passages.

Aging↗
PubMed1976

Nucleoside diphosphate kinase and the flagellar movement of glycerinated spermatozoa.

Nucleoside diphosphate kinase [EC 2.7.4.6.] of sperm flagella and Tetrahymena cilia is detected mostly in the outer fiber fraction, suggesting an association of the enzyme with the outer fiber microtubules. The enzyme does not catalyze transphosphorylation between microtubule-bound GDP and exogenous ATP. Even when undulatory movement of glycerinated sperm is induced by MgATP, no phosphorylation is detected in the outer fiber fraction. These facts do not appear to support the hypothesis that the phosphorylation of microtubule-bound GDP is involved in the mechanism of flagellar movement.

Adenosine Triphosphatases↗