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排序方式: 共有797条查询结果,搜索用时 11 毫秒
91.
Koyama S Nagahama T Ootsu N Takayama T Horii M Konishi S Miwa T Ishikawa Y Aizawa M 《Marine biotechnology (New York, N.Y.)》2005,7(4):272-278
We report successful larval hatching of deep-sea shrimp after decompression to atmospheric pressure. Three specimens of deep-sea shrimp were collected from an ocean depth of 1157 m at cold-seep sites off Hatsushima Island in Sagami Bay, Japan, using a pressure-stat aquarium system. Phylogenetic analysis of Alvinocaris sp. based on cytochrome c oxidase subunit gene sequences confirmed that these species were a member of the genus Alvinocaris. All 3 specimens survived to reach atmospheric pressure conditions after stepwise 63-day decompression. Two of the specimens contained eggs, which hatched after 10 and 16 days, respectively, of full decompression. Although no molting of the shrimp larvae was observed during 74 days of rearing under atmospheric pressure, the larvae developed conventional dark-adapted eyes after 15 days. 相似文献
92.
The low density lipoprotein receptor-related protein 1 (LRP1) has been implicated in intracellular signaling functions as well as in lipid metabolism. Recent in vivo and in vitro studies suggest that LRP1 is a physiological modulator of the platelet-derived growth factor (PDGF) signaling pathway. Here we show that in mouse fibroblasts LRP1 modulates PDGF-BB signaling by controlling endocytosis and ligand-induced down-regulation of the PDGF receptor beta (PDGFRbeta). In LRP1-deficient fibroblasts, basal PDGFRbeta tyrosine kinase activity was derepressed, and PDGF-BB-induced endocytosis and degradation of PDGFRbeta were accelerated as compared with control cells. This was accompanied by rapid uptake of receptor-bound PDGF-BB into the cells and by attenuated ERK activation in response to PDGF-BB stimulation. Pulse-chase analysis indicated that the steady-state turnover rate of PDGFRbeta was also accelerated in LRP-deficient fibroblasts. The rapid degradation of PDGFRbeta in the LRP1-deficient fibroblasts was prevented by MG132 and chloroquine. Furthermore, the association of PDGFRbeta with c-Cbl, a ubiquitin E3-ligase, as well as the ligand-induced ubiquitination of PDGFRbeta were increased in LRP1-deficient fibroblasts. We show that LRP1 can directly interact with c-Cbl, suggesting a Sprouty-like role for LRP1 in regulating the access of the PDGFRbeta to the ubiquitination machinery. Thus, LRP1 modulates PDGF signaling by controlling ubiquitination and endocytosis of the PDGFRbeta. 相似文献
93.
94.
Kusudo T Sakaki T Abe D Fujishima T Kittaka A Takayama H Hatakeyama S Ohta M Inouye K 《Biochemical and biophysical research communications》2004,321(4):774-782
The metabolism of 1alpha,25(OH)(2)D(3) (1alpha,3beta) and its A-ring diastereomers, 1beta,25(OH)(2)D(3) (1beta,3beta), 1alpha,25(OH)(2)-3-epi-D(3) (1alpha,3alpha), and 1beta,25(OH)(2)-3-epi-D(3) (1beta,3alpha), was examined to compare the substrate specificity and reaction specificity of CYP24A1 between humans and rats. The ratio between C-23 and C-24 oxidation pathways in human CYP24A1-dependent metabolism of (1alpha,3alpha) and (1beta,3alpha) was 1:1, although the ratio for (1alpha,3beta) and (1beta,3beta) was 1:4. These results indicate that the orientation of the hydroxyl group at the C-3 position determines the ratio between C-23 and C-24 oxidation pathways. A remarkable increase of metabolites in the C-23 oxidation pathway was also observed in rat CYP24A1-dependent metabolism. The binding affinity of human CYP24A1 for A-ring diastereomers was (1alpha,3beta)>(1alpha,3alpha)>(1beta,3beta)>(1beta,3alpha), indicating that both hydroxyl groups at C-1 and C-3 positions significantly affect substrate-binding. The information obtained in this study is quite useful for understanding substrate recognition of CYP24A1 and designing new vitamin D analogs. 相似文献
95.
Takayama E Higo T Kai M Fukasawa M Nakajima K Hara H Tadakuma T Igarashi K Yaoita Y Shiokawa K 《Biochemical and biophysical research communications》2004,325(4):1367-1375
We previously demonstrated that overexpression of S-adenosylmethionine decarboxylase (SAMDC) in Xenopus early embryos induces execution of maternal program of apoptosis shortly after midblastula transition, which likely serves as a fail-safe mechanism of early development to eliminate physiologically damaged cells before they entering the gastrula stage. To determine how caspases are involved in this process, we microinjected peptide inhibitors and "dominant-negative forms" of caspase-9 and -1 into Xenopus fertilized eggs, and found that inhibitors of caspase-9, but not caspase-1, completely suppress SAMDC-induced apoptosis. The lysate of SAMDC-overexpressing late blastulae contained activity to cleave in vitro-synthesized [(35)S]procaspase-9, but not [(35)S]procaspase-1, and mRNA for caspase-9, but not caspase-1, occurred abundantly in the unfertilized egg as maternal mRNA. We also found that overexpression of caspase-9 and -1 equally executes the apoptosis, but the apoptosis executed by these mRNAs was only partially rescued by Bcl-2 and rescued embryos did not develop beyond neurula stage. These results indicate that activation of caspase-9 is a key step for execution of the maternally preset program of apoptosis in Xenopus early embryos. 相似文献
96.
Matsumoto K Horie S Ishikawa H Takayama H Aimi N Ponglux D Watanabe K 《Life sciences》2004,74(17):2143-2155
Mitragynine is an indole alkaloid isolated from the Thai medicinal plant Mitragyna speciosa. We previously reported the morphine-like action of mitragynine and its related compounds in the in vitro assays. In the present study, we investigated the opioid effects of 7-hydroxymitragynine, which is isolated as its novel constituent, on contraction of isolated ileum, binding of the specific ligands to opioid receptors and nociceptive stimuli in mice. In guinea-pig ileum, 7-hydroxymitragynine inhibited electrically induced contraction through the opioid receptors. Receptor-binding assays revealed that 7-hydroxymitragynine has a higher affinity for micro-opioid receptors relative to the other opioid receptors. Administration of 7-hydroxymitragynine (2.5-10 mg/kg, s.c.) induced dose-dependent antinociceptive effects in tail-flick and hot-plate tests in mice. Its effect was more potent than that of morphine in both tests. When orally administered, 7-hydroxymitragynine (5-10 mg/kg) showed potent antinociceptive activities in tail-flick and hot-plate tests. In contrast, only weak antinociception was observed in the case of oral administration of morphine at a dose of 20 mg/kg. It was found that 7-hydroxymitragynine is a novel opioid agonist that is structurally different from the other opioid agonists, and has potent analgesic activity when orally administered. 相似文献
97.
Yuko Takayama Manami Itoi Takashi Hamahashi Noriyuki Tsukamoto Kazuya Mori Daisuke Morishita Kumiko Wada Takashi Amagai 《Microbiology and immunology》2010,54(9):551-557
Moxibustion is a technique used in traditional oriental medicine, the aim of which is to cure and/or prevent illness by activating a person's ability for self‐healing. In this study, we assessed how moxibustion would affect the immune system and whether it would augment protective immunity. Mice were treated with moxibustion at Zusanli (ST36) acupoints; we analyzed mortality and cytokine activity in sera after infection with herpes simplex virus type 1 (HSV‐1), and cytokine gene expression in the skin and the spleen without a virus challenge. Our study demonstrates that pretreatment of BALB/c mice with moxibustion resulted in a marked increase in the survival rate after infection with lethal doses of HSV‐1, and elevated serum levels of IL‐1β and IFN‐γ on days 1 and 6 post‐infection with HSV‐1. Semi‐quantitative RT‐PCR assay showed that moxibustion treatment augmented the expression of IL‐1α, IL‐1β, IL‐6, universal‐IFN‐α, MIP‐1α, and TNF‐α mRNA in the skin, and IL‐1α, IL‐1β, IL‐12p40, IL‐15, u‐IFN‐α, MIP‐1α, and TNF‐α mRNA in the spleen. Moreover, moxibustion induces augmentation of natural killer cell activity. Collectively, our study demonstrates that moxibustion activates protective responses against HSV‐1 infection through the activation of cytokine production including IFN, and of NK cells. 相似文献
98.
99.
Mineno J Okamoto S Ando T Sato M Chono H Izu H Takayama M Asada K Mirochnitchenko O Inouye M Kato I 《Nucleic acids research》2006,34(6):1765-1771
100.