Chromosome condensation caused by loss of RCC1 function requires the cdc25C protein that is located in the cytoplasm.

We cloned the hamster cdc25C cDNA by using the human cdc25C cDNA as a probe and prepared an antibody to Escherichia coli-produced hamster cdc25C protein that is specific to the human cdc25C protein. The microinjected antibody inhibited a chromosome condensation induced by tsBN2 mutation, indicating that the cdc25C protein is required for an activation of p34cdc2 kinase caused by loss of RCC1 function. The hamster cdc25C protein located in the cytoplasm, prominently in a periphery of the nuclei of cells arrested with hydroxyurea, and seemed to move into the nuclei by loss of RCC1 function. Also, we found a molecular shift of the cdc25C protein in cells showing premature chromosome condensation (PCC), in addition to normal mitotic cells. This molecular-shift appeared depending on an activation of p34cdc2 kinase.     

Activin A stimulates meiotic maturation of the rat oocyte in vitro

The effect of activin A on meiotic maturation was analyzed in oocytes from immature rats treated with PMSG. Activin A, which was purified as the erythroid differentiation factor, accelerated the maturation of not only follicle-enclosed oocytes and oocyte-cumulus complexes, but also denuded oocytes, as measured by an increase in the percentage of oocytes with germinal vesicle breakdown (GVBD). Oocyte maturation was not accelerated by activin A in the presence of the inhibitor of GVBD such as cyclic-AMP. These results showed activin A is a potent in vitro stimulator of oocyte maturation.     

Purine nucleoside modulation of functions of human lymphocytes.

The accumulation of endogenous substrates in patients with adenosine deaminase deficiency or purine nucleoside phosphorylase deficiency is believed to be responsible for the immunodeficiency observed in these patients. To identify the lymphocyte populations that are most susceptible to these substrates, we investigated the effect of their nucleoside analogs on a number of T and B cell functions of human lymphocytes. We found that tubercidin (Tub), 2-chloro 2'deoxyadenosine (2CldA), 2-fluoro adenine arabinoside-5'phosphate (FaraAMP), and 9-beta-D-arabinosyl guanine (AraGua) inhibited the proliferative responses of human peripheral blood mononuclear cells (PBMC) to polyclonal activators (PHA, OKT3 mab) or to allogeneic PBMC in mixed lymphocyte cultures (MLC). Addition of recombinant IL-2 from the beginning of the culture did not alter the inhibition by Tub of the proliferative responses of PBMC. These purine nucleoside analogs also inhibited the proliferative responses of purified human peripheral blood CD4+ and CD8+ T cells to PHA and of purified B cells to SAC. The concentrations of these nucleosides required to achieve a given degree of inhibition of proliferative responses of T lymphocyte subpopulations or B cells was similar, suggesting that these analogs do not exhibit any selectivity for these purified lymphocyte populations. Tub and FaraAMP, respectively, inhibited and enhanced, at the effector phase, both NK cytotoxicity and specific T cell-mediated cytotoxicity. In contrast to these findings, LAK cytotoxicity at the effector phase was not significantly inhibited by Tub, and was not enhanced by FaraAMP. Both analogs inhibited rIL-2-induced proliferative responses of PBMC, but did not affect the generation of LAK cytotoxicity (induction phase) against the K562 targets when added at the beginning of the culture. This suggests that DNA synthesis is not required for LAK cell induction. Both Tub and FaraAMP inhibited immunoglobulin production (IgG and IgM) by PBMC in the PWM-induced system. These results demonstrate that purine nucleoside analogs significantly inhibited a number of functions of human lymphocytes. Although selectivity for T lymphocyte subpopulations and B cells was not observed, a differential effect of Tub and FaraAMP on LAK cytotoxicity versus NK cytotoxicity and specific T cell cytotoxicity was found.     

Temperature dependency of induction of sexual agglutinability by α pheromone in the yeast Saccharomyces cerevisiae

When pheromone-pretreated cells of an inducible a strain of Saccharomyces cerevisiae carrying the inducible gene saa1 were incubated in a growth medium at 28°C, induction of sexual agglutinability began after a 10 min lag period. If the cells were incubated at 38°C during the lag period, no induction occurred even after incubation at 28°C. Contrary to this, if the cells were incubated at 28°C during the lag period, almost complete induction occurred, even after transfer to 38°C. Temperature shift experiments revealed that 5 min incubation at 28°C was necessary for the initiation of the temperature-sensitive period and further 5 min incubation for the completion of the period. The temperature-sensitive period was sensitive to phenylmethylsulfonyl fluoride.Non-common abbreviations PBS 10^-2 M phosphate buffer solution, pH 5.5 - PMSF phenylmethylsulfonyl fluoride     

Changes in sexual agglutination ability during the formation of vegetative cells from spores in Saccharomyces cerevisiae

Summary Spores of heterothallic diploid cells of Saccharomyces cerevisiae had neither a nor agglutination substance in either cell wall or cytoplasmic fraction; they, however, showed selfagglutination not caused by sex-specific agglutination substances. Meanwhile, practically no sexual agglutination was detected during germination and outgrowth of the spores; it arose after emergence of the first buds and progressed with incubation time. Its ability increased gradualy until the first bud emergence and rapidly thereafter. a and agglutination substances were detected in both cell wall and cytoplasmic fractions of cells from an 8h-old spore culture. Only germinated spores with buds had the ability to produce and to respond to the a pheromone.     

Streptococcal preparation OK-432 augments cytotoxic activity against an erythroleukemic cell line in humans

Summary The effects of OK-432, an inactivated and lyophilized preparation of a low-virulence strain of Streptococcus pyogenes, were evaluated on the cytotoxicity of lymphoid cells against a natural killer (NK)-sensitive erythroleukemic cell line K562 in patients with malignant diseases. When ten patients were treated postoperatively with daily injections of OK-432, a significant degree of augmentation in the cytotoxicity of peripheral blood lymphoid cells was evoked in all the patients, and the maximum level of cytotoxicity was on the third day after the beginning of the treatment. In spite of the successive daily administration, the level of cytotoxicity declined thereafter, but stayed higher than the pretreatment level. When OK-432 was injected IP in three patients with carcinomatous peritonitis, the cytotoxic activity of ascitic lymphoid cells was significantly enhanced. Cytotoxicity of in vitro-cultured lymphoid cells taken from peripheral blood of normal donors was also augmented by the addition of OK-432.     

Mating reaction in Saccharomyces cerevisiae. X Agglutinability-inactivating factor: A factor which destroys sexual agglutinability of a mating-type cells

From cells of Saccharomyces cerevisiae a factor has been extracted that destroys the agglutinability of a mating-type cells specifically. It was found in the cell extracts of diploid and tetraploid strains as well as haploid strains of a and mating types. It is heat-labile and the molecular weight is about 50000. It is adsorbed by neither a cells nor cells. Its biological activity is dependent on the incubation temperature and the pH, and is completely inhibited by phenylmethylsulfonyl fluoride, a potent inhibitor of the serine proteases. All the results described in this paper indicate that this factor is a proteolytic enzyme.     

COLONY-FORMING ABILITY OF BONE MARROW CELLS OF W ANAEMIC MICE ON MACROPHAGE LAYER FORMED IN PERITONEAL CAVITY OF MICE

The colony-forming ability of haematopoietic cells of W anaemic mice was examined on the macrophage layer formed in the peritoneal cavity of mice. Bone marrow cells of W anaemic mice formed a considerable number of colonies on the macrophage layer, notwithstanding they did not form any colonies in the spleen of the same recipients. As the colony-forming ability of the bone marrow cells was not reduced by the incubation with ³H-thymidine, most of the cells which formed colonies on the macrophage layer seemed to stay in G₀ state. The interrelationship between the spleen colony-forming cells, the macrophage-layer colony-forming cells, and in vitro colony-forming cells was discussed.     

Recessive and dominant genes controlling inducible sexual agglutinability in Saccharomyces cerevisiae

Summary We have characterized the two dominant genes, IND 1 and IND 2, responsible for inducible sexual agglutinability. The strains carrying these genes differ from the inducible strains carrying the recessive gene, saa 1 in the following points. The former strains produce agglutination substance at 22°, 28°, and 37° C only in response to sex pheromone of the opposite mating type, but the latter strains produce the substance constitutively without the pheromone at 22° C, only in response to the pheromone at 28° C, and do not produce the substance, even in the presence of the pheromone, at 37° C.We suggest that strains carrying one of the dominant, inducible genes are wild type and have a pheromone-controlled regulatory system of sexual agglutinability.     

A simple method for observation of phagocytosis on bacterial thin-layer

A simple method was developed to visually present the phagocytic activity of leukocytes by using adherent Staphylococcus aureus cells and blood applied on a plastic dish. When heparinized blood was applied on thin-layer of heat-killed S. aureus cells on the plastic dish, plaques due to the phagocytic activity of leukocytes were observed with a microscope under a low magnification. Fewer and smaller plaques were observed when plasma-deprived rather than whole blood was used. Some analyses were made in respect to the fundamental conditions required for optimal results. This method was considered to be useful for conveniently evaluating the serum opsonin activities and phagocytic function of leukocytes in various kinds of diseases.