Indirect free-exciton luminescence in AgCl single crystal accompanied by TO(L) phonon emission is found for the first time at 382.9 nm (3.238 eV) at 2 K for picosecond pulse laser excitation at 351 nm (3.53 eV). The luminescence decay curve monitored at 382.9 nm has a fast decay component, 20 ps, which is interpreted as the self-trapping time of holes generated at the L point. A luminescence band peaking at 385 nm (3.221 eV) is found, which is assigned as due to the optical transition from a point around the exit of the quantum mechanical tunneling process through the self-trapping potential barrier. The rise time 70 ps is interpreted as the time required for tunneling. A luminescence band peaking at 386.5 nm (3.208 eV) is found and assigned to be due to excitons bound by shallow impurity.
We have re-evaluated the effects of bestatin, an aminopeptidase-N (CD13) inhibitor, on in vitro decidualization of normal human endometrial stromal cells by using an in vitro decidualization activity assay. Bestatin did not show any effects on the viability of both the decidualizing stromal cells co-stimulated with 8-Br-cAMP and bestatin and the 8-Br-cAMP-induced decidualized stromal cells, or on prolactin release from the decidualized stromal cells. However, bestatin dose-dependently enhanced prolactin release from the decidualizing stromal cells co-stimulated with 8-Br-cAMP and bestatin. These results indicate that bestatin enhances cAMP-mediated decidualization of human endometrial stromal cells and suggests that membrane aminopeptidase-N in the human endometrium is involved in the regulation of endometrial differentiation by inhibiting cAMP-mediated decidualization signals in endometrial stromal cells.
The luminescence spectra in ß-perylene crystals reveal a strange temperature dependence 1) (Figure 1). Analysis of the spectra provides clear evidence that at high temperatures the free exciton luminescence and the deeper self-trapped exciton luminescence dominate, while at low temperatures the shallower self-trapped exciton luminescence dominates.
ATP-dependent chromatin remodelers (ADCRs) convert local chromatin structure into both transcriptional active and repressive state. Recent studies have revealed that ADCRs play diverse regulatory roles in chromosomal events such as DNA repair and recombination. Here we have newly identified a fission yeast gene encoding a Swi2/Snf2 family ADCR. The amino acid sequence of this gene, snf21+, implies that Snf21 is a fission yeast orthologue of the budding yeast Sth1, the catalytic core of the RSC chromatin remodeling complex. The snf21+ gene product is a nuclear protein essential to cell viability: the null mutant cells stop growing after several rounds of cell divisions. A temperature sensitive allele of snf21+, snf21-36 exhibits at non-permissive temperature (34°C) a cell cycle arrest at G2-M phase and defects in chromosome segregation, thereby causing cell elongation, lack of cell growth, and death of some cell population. snf21-36 shows thiabendazole (TBZ) sensitivity even at permissive temperature (25°C). The TBZ sensitivity becomes severer as snf21-36 is combined with the deletion of a centromere-localized Mad2 spindle checkpoint protein. The cell cycle arrest phenotype at 34°C cannot be rescued by the mad2+ deletion, although it is substantially alleviated at 30°C in mad2Δ. These data suggest that Snf21 plays an essential role in mitosis possibly functioning in centromeric chromatin.
Porcine nuclear transfer embryos were reconstructed by intracytoplasmic nuclear injection of cumulus cell nuclei into recipient oocytes matured in vitro by two types of method (NCSU23-based and TCM199-based methods). Remodelling of the transferred nuclei and in vitro development of the reconstructed embryos were investigated. Intracytoplasmic nuclear injection did not induce activation of the recipient oocytes regardless of the type of maturation method (NCSU23-based: 61/61, 100%, TCM199-based: 49/50, 98%). When the reconstructed embryos were examined 1 h after nuclear injection many of them (NCSU23-based: 22/29, 76%; TCM199-based: 19/23, 83%) possessed condensed chromosomes or a chromosome array resembling the maternal metaphase plate. The proportion of the reconstructed embryos possessing condensed chromosomes arranged in a scattered fashion showed a tendency to increase, when they were examined 2-5 h after nuclear injection. Reconstructed embryos were electrically activated either 2-2.5 h or 3.5-4 h after nuclear injection, followed by fixation/staining to examine formation of pronucleus-like nuclei (pseudo-nuclei). Regardless of the nuclear injection/activation interval tested, 68% (36/53) of the reconstructed embryos developed pseudo-pronuclei ranging in number between 1 and 4. When the reconstructed embryos were cultured for 7 days to assess their developmental competence, 5 (5/98) to 11% (12/111) developed to blastocysts regardless of the type of the recipient oocyte and nuclear injection/activation intervals. These results show that intracytoplasmic injection of porcine cumulus cell nuclei achieves a high rate of nuclear remodelling and that the reconstructed embryos are capable of developing into blastocysts.
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