Showing papers in "Experimental Cell Research in 1965"

TL;DR: The survival curves obtained with human diploid cell strains are comparable to “multiple-hit” or “ multiple-target” curves obtain with other biological systems where an initial threshold dose is required before an exponential form of the curve is established.

TL;DR: A number of evidences suggest that this “arginine-rich” spermatid histone is effectively synthesized within the nucleus, although the alternative interpretation of a cytoplasmic synthesis followed by transfer of the newly synthesized histone into the nucleus cannot be actually rejected.

TL;DR: Cells at the top of the proliferation zone show considerable uniformity in the length of the periods of the cycle, and cells in mitosis and cells which incorporate 3H-thymidine are presented for the upper jejunum of male August rats.

TL;DR: The average mitotic cycle duration of root meristem cells of several plants was measured with 3H-thymidine and showed that the cycle duration increases with an increase in the DNA content per cell and the average rate of DNA synthesis increased.

TL;DR: The importance of such a critical mass was discussed with regard to maintenance of the size homogeneity of the cell population, intercellular variations in generation times and the “trigger” mechanism for mitosis.

TL;DR: The mass of cells entering interphase after cell division, initial mass (mo), and the cell mass at the stage of initiation of DNA synthesis (mG1) were determined in 21 populations of mouse fibroblasts in vitro (L-cells) which exhibited different mo values.

TL;DR: La synthese du RNA nucleolaire sur le DNA lie au nucleole se trouve deja apres 5 mn de marquage dans les zones fibrillaires du nucleole dans le noyau pourrait correspondre au RNA messager.

TL;DR: Mitochondrial fibers with DNA-characteristics are described from a large number of cell types, representing different tissues taken from animals of eight phyla, showing that the DNA is an integral part of most and probably all mitochondria, although the fibers in some cases are difficult to visualize.

TL;DR: Dichloroisoproterenol caused no alteration of the weight, DNA-content and incorporation of thymidine in the submaxillary gland and it partly prevented the effect of IPR.

TL;DR: The results suggested that the cell proliferation in the salivary gland induced by isoproterenol may be regulated by a number of factors but the triggering mechanism probably acts on a genetic level.

TL;DR: By means of theoretical phase distribution diagrams, the labelling and mitotic indices at various levels in the crypt are predicted and compared with those found by experiment; in this way the model is substantiated and the biological implications of the model are considered.

TL;DR: Rat peritoneal mast cells were subjected to a morphological study as well as histamine determinations after incubation with varying low concentrations of the histamine liberator, compound 48 80 .

TL;DR: Dabei fand sich, dass das Zeitintervall zwischen dem Anfang der DNS-Verdopplung and dem Ende der Mitose bei den einzelnen Zellarten relativ konstant ist, wahrend die Generationszeiten sehr grosse Unterschiede zeigen.

TL;DR: The technique routinely used for measuring G2 + P and other parts of the cycle was shown to be unreliable under certain conditions and, as expected, each part of the Cycle except anaphase has a U-shaped temperature-response curve.

TL;DR: An investigation was made of the kinetics of nucleic acid and protein (dry mass) synthesis during interphase of mouse fibroblasts in vitro, finding the rate of RNA synthesis seemed to occur predominantly during the second half of interphase at the same time as the doubling of the amount of DNA in the cell.

TL;DR: Assays of DNA polymerase andThymidine kinases indicated that synthesis of these enzymes after thymidine addition could not account for the requirement for protein synthesis, and it is suggested that a particular protein must be made which controls the initiation of replication.

TL;DR: It was concluded that the source of variation in generation times of rat sarcoma cells in tissue culture is a combination of genetic and nongenetic factors.

TL;DR: Tobacco cells in suspension culture multiplied exponentially with a generation time of two days and the mode of replication was semi-conservative, indicating that all the DNA replicated in slightly more than two days.

TL;DR: Results indicate that RNAs required for mitosis are formed one to one and one-half cycles prior to that mitosis.

TL;DR: It is concluded that in the cells of the mammary gland DNA synthesis is not an unadjustable process of the generative cycle, but varies with the proliferation rate, and the hypothesis of absence of correlation between duration of the DNA synthetic phase and generation time appears to be disproved.

TL;DR: The results show that cultured epithelial explants will respond with a resumption of growth, with further cellular differentiation, and with at least some of the morphogenetic changes necessary to form a lens when returned to the eye environment, and the embryonic coelom will not support these responses.

TL;DR: The findings and measurements of total DNA, RNA, and proteins per heart ventricles suggest that the ventricular myocardium of mice grows in the first 4 weeks after birth mainly by production of new cells, a process continuing but at a greatly reduced rate up to 4 months of age.

TL;DR: The results support the idea that the total capacity for protein synthesis during interphase growth is controlled by the existing number of ribosomes in the cell.

TL;DR: Cultures consisting exclusively of monolayered immature astrocytes with superimposed migratory spongioblasts were prepared by trypsinization of human fetal brain of 412 − 5 months' gestation to identify cell types and characteristics remained stable in each cell type through serial passages during more than four months' cultivation.

TL;DR: An autoradiography method based upon the affinity of actinomycin D for the intact DNA molecule has been developed and results show the presence of DNA within the cytoplasm of the large ovocytes.

TL;DR: These features indicate that bull sperm mitochondria possess biochemical properties closely resembling those of mitochondria from other tissues, in spite of their greatly modified structure, and suggest a possible source of glycerol-1-phosphate, which is rapidly oxidized by the midpiece fraction.