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51.
Celina M Haraguchi Tadashi Mabuchi Shuji Hirata Tomoko Shoda Toshinobu Tokumoto Kazuhiko Hoshi Sadaki Yokota 《The journal of histochemistry and cytochemistry》2007,55(6):585-595
Many temporarily functioning proteins are generated during the replacement of nucleoproteins in the nuclei of late spermatids and seem to be degraded in the nucleus. This study was designed to clarify the involvement of the ubiquitin-proteasome degradation system in the nucleus of rat developing spermatids. Thus, we studied the nuclear distribution of polyubiquitinated proteins (pUP) and proteasome in spermiogenic cells and sperm using postembedding immunoelectron microscopy. We divided the nuclear area of late spermatids into two regions: (1) a dense area composed of condensed chromatin and (2) a nuclear pocket in the neck region. The latter was located in the caudal nuclear region and was surrounded by redundant nuclear envelope. We demonstrated the presence of pUP in the dense area and nuclear pocket, proteasome in the nuclear pocket, and clear spots in the dense area of rat spermatids. Using quantitative analysis of immunogold labeling, we found that fluctuation of pUP and proteasome levels in late spermatogenesis was mostly synchronized with disappearance of histones and transitional proteins reported previously. In the nuclei of human sperm, pUP was detected in the dense area, whereas proteasome was in the nuclear vacuoles and clear spots. These results strongly suggest that pUP occur in the dense nuclear area of developing spermatids and that the ubiquitin-proteasome system is more actively operational in the nuclear pocket than dense area. Thus, the nuclear pocket might be the degradation site for temporarily functioning proteins generating during condensation of chromatin in late spermatids. 相似文献
52.
Yoshihara Shizue Yamamoto Kasumi Nakajima Yoshino Takeda Satomi Kurahashi Kensuke Tokumoto Hayato 《Plant Cell, Tissue and Organ Culture》2019,138(2):377-385
Plant Cell, Tissue and Organ Culture (PCTOC) - Zinc oxide (ZnO) nanoparticles (NPs) are soluble in water and can release Zn2+, an essential mineral that promotes the growth of plant cells. When ZnO... 相似文献
53.
Masahiko Morita Toshio Hayashi Masayuki Ochiai Morihiko Maeda Tomoe Yamaguchi Koichiro Ina Masafumi Kuzuya 《Biochemical and biophysical research communications》2014
Background
Chronic supplementation with l-citrulline plus l-arginine has been shown to exhibit anti-atherosclerotic effects. However, the short-term action of this combination on the nitric oxide (NO)–cGMP pathway remains to be elucidated. The objective of the present study was to investigate the acute effects of a combination of oral l-citrulline and l-arginine on plasma l-arginine and NO levels, as well as on blood circulation.Methods
Rats or New Zealand white rabbits were treated orally with l-citrulline, or l-arginine, or a combination of each at half dosage. Following supplementation, plasma levels of l-arginine, NOx, cGMP and changes in blood circulation were determined sequentially.Results
l-Citrulline plus l-arginine supplementation caused a more rapid increase in plasma l-arginine levels and marked enhancement of NO bioavailability, including plasma cGMP concentrations, than with dosage with the single amino acids. Blood flow in the central ear artery in rabbits was also significantly increased by l-citrulline plus l-arginine administration as compared with the control.Conclusion
Our data show for the first time that a combination of oral l-citrulline and l-arginine effectively and rapidly augments NO-dependent responses at the acute stage. This approach may have clinical utility for the regulation of cardiovascular function in humans. 相似文献54.
Mitsuo Nunome Gohta Kinoshita Morihiko Tomozawa Harumi Torii Rikyu Matsuki Fumio Yamada Yoichi Matsuda Hitoshi Suzuki 《Biological journal of the Linnean Society. Linnean Society of London》2014,111(4):761-776
Seasonal changes in fur colour in some mammalian species have long attracted the attention of biologists, especially in species showing population variation in these seasonal changes. Genetic differences among populations that show differences in seasonal changes in coat colour have been poorly studied. Because the Japanese hare (Lepus brachyurus) has two allopatric morphotypes that show remarkably different coat colours in winter, we examined the population genetic structure of the species using partial sequences of the SRY gene and six autosomal genes: three coat colour‐related genes (ASIP, TYR, and MC1R) and three putatively neutral genes (TSHB, APOB, and SPTBN1). The phylogenetic tree of SRY sequences exhibited two distinct lineages that diverged approsimately 1 Mya. Although the two lineages exhibited a clear allopatric distribution, it was not consistent with the distribution of morphotypes. In addition, six nuclear gene sequences failed to reveal genetic differences between morphotypes. Population network trees for 11 expedient populations divided the populations into four groups. Genetic structure analysis revealed an admixture of four genetic clusters in L. brachyurus, two of which showed large genetic differences. Our results suggest ancient vicariance in L. brachyurus, and we detected no genetic differences between the two morphotypes. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 761–776. 相似文献
55.
56.
A Tumor Suppressor Gene Product,Platelet‐Derived Growth Factor Receptor‐Like Protein Controls Chondrocyte Proliferation and Differentiation 下载免费PDF全文
57.
The timing of oligodendrocyte differentiation is thought to depend on both intracellular mechanisms and extracellular signals. Thyroid hormone (TH) helps control this timing both in vitro and in vivo, but it is still uncertain how it does so. TH acts through nuclear receptors that are encoded by two genes, TRalpha and TRbeta. Previous studies suggested that TRbeta receptors may mediate the effect of TH on oligodendrocyte precursor cells (OPCs). Consistent with this possibility, we show here that overexpression of TRbeta1 promotes precocious oligodendrocyte differentiation, whereas expression of two dominant-negative forms of TRbeta1 greatly delays differentiation. Surprisingly, however, we find that postnatal TRbeta-/- mice have a normal number of oligodendrocytes in their optic nerves and that TRbeta-/- OPCs stop dividing and differentiate normally in response to TH in vitro. Moreover, we find that OPCs do not express TRbeta1 or TRbeta2 mRNAs, whereas they do express TRalpha1 and TRalpha2 mRNAs. These findings suggest that alpha receptors mediate the effect of TH on the timing of oligodendrocyte differentiation. We also show that TRalpha2 mRNA, which encodes a dominant-negative form of TRalpha, decreases as OPCs proliferate in vitro and in vivo. This decrease may help control when oligodendrocyte precursors differentiate. 相似文献
58.
T Sugimoto M Amano T Tokumoto K Ishikawa 《Biochemical and biophysical research communications》1999,264(3):689-695
An unusual phosphatase, which is resistant to treatment by 5% SDS and proteolytic enzymes, was isolated as two types, 1 and 2, from pronase-treated homogenates of Xenopus ovary. The molecular sizes of types 1 and 2 were estimated as about 140 kDa and more than 2 x 10(4) kDa, respectively, by gel filtration, but as 140 and 130 kDa as a catalytic unit, respectively, by electrophoresis, implying that whereas type 1 might be composed of catalytic unit alone, type 2 is a multicomponent complex consisting of a 130-kDa catalytic unit. Both activities were sensitive to nucleases but resistant to tested proteolytic enzymes. These findings suggest that the unusual phosphatase activity is attributable to a polynucleotide. 相似文献
59.
Hiroyasu Kinemuchi Miyuki Sudo Morihiko Yoshino Takamori Kawaguchi Yumi Sunami Kazuya Kamijo 《Life sciences》1983,32(5):517-524
The characteristics of mitochondrial monoamine oxidase (MAO) in carp liver were studied with MAO inhibitors and substrates. This enzyme was thermolabile, but was stabilized in the presence of bovine serum albumin. With clorgyline and deprenyl, single-sigmoidal curves for inhibition of the activity towards tyramine or 5-hydroxytryptamine were obtained; the sensitivities to the two inhibitors were identical. The activity towards β-phenylethylamine was not completely inhibited by clorgyline or deprenyl, but the remaining activity was inhibited by semicarbazide and the inhibition curves by either clorgyline or deprenyl and semicarbazide were also identical to the curves with the other two substrates. These results suggest that carp liver mitochondria contain “classical” MAO and a clorgyline- and deprenyl-resistant amine oxidase and that the classical MAO does not seem to be MAO-A or MAO-B, which are present in mitochondria of most mammalian tissues. 相似文献
60.
Systematic fractionation of oligosaccharides of human immunoglobulin G by serial affinity chromatography on immobilized lectin columns 总被引:1,自引:0,他引:1
H Harada M Kamei Y Tokumoto S Yui F Koyama N Kochibe T Endo A Kobata 《Analytical biochemistry》1987,164(2):374-381
Human immunoglobulin G is known to contain 16 different biantennary complex-type asparagine-linked sugar chains, each of which occurs in a nonsialylated, monosialylated, or disialylated form. These oligosaccharides can be separated into 14 fractions by sequential affinity chromatography with Aleuria aurantia lectin (AAL)-Sepharose, RCA120-WG003, and E4-phytohemagglutinin-agarose columns. Twelve of them were found to contain a single oligosaccharide, while the fraction which passed through all three columns was shown to contain two oligosaccharides, GlcNAc beta 1----2Man alpha 1----6(+/- GlcNAc beta 1----4) (GlcNAc beta 1----2Man alpha 1----3)Man beta 1----4GlcNAc beta 1----4GlcNAcOT. The fraction, which bound to the AAL-Sepharose column and passed through the remaining two lectin columns, also contained two oligosaccharides, GlcNAc beta 1----2Man alpha 1----6(+/- GlcNAc beta 1----4) (GlcNAc beta 1----2Man alpha 1----3)Man beta 1----4GlcNAc beta 1----4 (Fuc alpha 1----6)GlcNAcOT. These results indicated that serial affinity chromatography with the three lectin columns can be used effectively to detect changes in the sugar chains of IgG resulting from diseases such as rheumatoid arthritis. 相似文献