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91.
Tohda A Matsumiya K Tadokoro Y Yomogida K Miyagawa Y Dohmae K Okuyama A Nishimune Y 《Biology of reproduction》2001,65(2):532-537
Male juvenile spermatogonial depletion (jsd/jsd) mice are sterile because of a failure of spermatogonial differentiation. We have previously reported the recovery of spermatogonial differentiation by suppressing the levels of gonadotropins and testosterone with Nal-Glu, a GnRH antagonist. To determine whether suppression of testosterone or the gonadotropins was responsible for spermatogenic recovery, we examined the effect of supplementation of LH or FSH along with Nal-Glu treatment. Systemic administration of flutamide, an androgen receptor antagonist, was also examined. LH supplementation elevated both serum and intratesticular testosterone levels and suppressed the recovery of spermatogonial differentiation in a dose-dependent manner. Supplementation with FSH did not affect either testosterone levels or spermatogonial differentiation. Furthermore, the mice treated with flutamide showed some recovery of spermatogonial differentiation. The overall findings revealed that testosterone action mediated by androgen receptors suppressed the spermatogonial differentiation in jsd/jsd mice and suggested that spermatogonial differentiation in the jsd mutant is highly sensitive to testosterone suppression. 相似文献
92.
93.
Crystal structure of an archaeal DNA sliding clamp: proliferating cell nuclear antigen from Pyrococcus furiosus
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Matsumiya S Ishino Y Morikawa K 《Protein science : a publication of the Protein Society》2001,10(1):17-23
The proliferating cell nuclear antigen (PCNA) is now recognized as one of the key proteins in DNA metabolic events because of its direct interactions with many proteins involved in important cellular processes. We have determined the crystal structure of PCNA from a hyperthermophilic archaeon, Pyrococcus furiosus (pfuPCNA), at 2.1 A resolution. pfuPCNA forms a toroidal, ring-shaped structure consisting of homotrimeric molecules, which is also observed in the PCNA crystals from human and yeast. The overall structure of pfuPCNA is highly conserved with other PCNA proteins, as well as with the bacterial ss clamp and the bacteriophage gp45. This result shows that the three-dimensional structure of the sliding clamp is conserved in the three domains of life. pfuPCNA has two remarkable features compared with the human and yeast PCNA molecules: it has more ion pairs and fewer intermolecular main chain hydrogen bonds. The former may contribute to the thermal stability of pfuPCNA, and the latter may be the cause of the stimulatory effect of pfuPCNA on the DNA synthesizing activity of P. furiosus DNA polymerases in the absence of the clamp loader replication factor C in vitro. 相似文献
94.
For the pyrochemical reprocessing of spent metallic fuels in molten salt baths it is of importance to investigate the electronic and dynamic properties of the negative elements like Cs in aluminosilicates framework. The molecular orbital simulation has been performed on three types of clusters and 4A-zeolite frameworks with exchangeable alkali-ions containing as significant fission products in order to estimate the geometry optimization, the vibrational frequency factors and the electric densities, etc. These quantum chemical results enable us to conclude that the most stable structure is consistent with the X-ray results. Moreover, the obtained infrared spectrum was reproduced by the experimental results. Furthermore, the molecular dynamics simulation for Na-A and Cs-A zeolites has been carried out at 673 K in order to investigate the dynamics of Na+ and Cs+ions in Na-A and Cs-A zeolite frameworks. These results revealed that Na I ion in β-cage was more stable than the other Na ions in Na-A zeolite and Cs I ion in α-cage was maintained stability in Cs-A zeolite in consideration of the self-diffusion coefficients. 相似文献
95.
Suiho Yanagisawa Yoichi Sakurada Akiko Miki Wataru Matsumiya Issei Imoto Shigeru Honda 《PloS one》2015,10(3)
Objective
To compare the association of elastin (ELN) gene variants between two different angiographic phenotypes of polypoidal choroidal vasculopathy (PCV).Methods
We included 411 treatment-naïve PCV patients and 350 controls in the present study. PCV was classified into two phenotypes (152 Type 1 and 259 Type 2) according to the presence or absence of feeding vessels found in indocyanine-green angiography. Single nucleotide polymorphisms (SNPs) in the ELN region including rs868005, rs884843, rs2301995, rs13239907 and rs2856728 were genotyped using TaqMan Genotyping Assays.Results
In the allelic association analyses, rs868005 showed the strongest association with Type 2 PCV (allelic odds ratio 1.56; p = 7.4x10-6), while no SNP was significantly associated with Type 1 PCV. Genotype association analyses revealed the significant association of rs868005 with Type 2 PCV in log additive model and predominant model (odds ratio 1.75; p = 1.5x10-6 and odds ratio 1.60; p = 0.0044, respectively), but not with Type 1 PCV. These findings were further corroborated by another control group in the literature.Conclusions
There may be significantly different associations in genetic variants of elastin between two angiographic phenotypes of PCV. 相似文献96.
97.
Recent extensive studies have revealed that molecular hydrogen (H(2)) has great potential for improving oxidative stress-related diseases by inhaling H(2) gas, injecting saline with dissolved H(2), or drinking water with dissolved H(2) (H(2)-water); however, little is known about the dynamic movement of H(2) in a body. First, we show that hepatic glycogen accumulates H(2) after oral administration of H(2)-water, explaining why consumption of even a small amount of H(2) over a short span time efficiently improves various disease models. This finding was supported by an in vitro experiment in which glycogen solution maintained H(2). Next, we examined the benefit of ad libitum drinking H(2)-water to type 2 diabetes using db/db obesity model mice lacking the functional leptin receptor. Drinking H(2)-water reduced hepatic oxidative stress, and significantly alleviated fatty liver in db/db mice as well as high fat-diet-induced fatty liver in wild-type mice. Long-term drinking H(2)-water significantly controlled fat and body weights, despite no increase in consumption of diet and water. Moreover, drinking H(2)-water decreased levels of plasma glucose, insulin, and triglyceride, the effect of which on hyperglycemia was similar to diet restriction. To examine how drinking H(2)-water improves obesity and metabolic parameters at the molecular level, we examined gene-expression profiles, and found enhanced expression of a hepatic hormone, fibroblast growth factor 21 (FGF21), which functions to enhance fatty acid and glucose expenditure. Indeed, H(2) stimulated energy metabolism as measured by oxygen consumption. The present results suggest the potential benefit of H(2) in improving obesity, diabetes, and metabolic syndrome. 相似文献
98.
Hazeki K Kametani Y Murakami H Uehara M Ishikawa Y Nigorikawa K Takasuga S Sasaki T Seya T Matsumoto M Hazeki O 《PloS one》2011,6(10):e26836
Synthetic oligodeoxynucleotides containing unmethylated CpG motifs (CpG) stimulate innate immune responses. Phosphoinositide 3-kinase (PI3K) has been implicated in CpG-induced immune activation; however, its precise role has not yet been clarified. CpG-induced production of IL-10 was dramatically increased in macrophages deficient in PI3Kγ (p110γ(-/-)). By contrast, LPS-induced production of IL-10 was unchanged in the cells. CpG-induced, but not LPS-induced, IL-10 production was almost completely abolished in SCID mice having mutations in DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Furthermore, wortmannin, an inhibitor of DNA-PKcs, completely inhibited CpG-induced IL-10 production, both in wild type and p110γ(-/-) cells. Microscopic analyses revealed that CpG preferentially localized with DNA-PKcs in p110γ(-/-) cells than in wild type cells. In addition, CpG was preferentially co-localized with the acidic lysosomal marker, LysoTracker, in p110γ(-/-) cells, and with an early endosome marker, EEA1, in wild type cells. Over-expression of p110γ in Cos7 cells resulted in decreased acidification of CpG containing endosome. A similar effect was reproduced using kinase-dead mutants, but not with a ras-binding site mutant, of p110γ. Thus, it is likely that p110γ, in a manner independent of its kinase activity, inhibits the acidification of CpG-containing endosomes. It is considered that increased acidification of CpG-containing endosomes in p110γ(-/-) cells enforces endosomal escape of CpG, which results in increased association of CpG with DNA-PKcs to up-regulate IL-10 production in macrophages. 相似文献
99.
100.
Edward P. Glenn Pamela L. Nagler Kiyomi Morino Kevin R. Hultine 《Plant and Soil》2013,371(1-2):655-672