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31.
Kedishvili NY Chumakova OV Chetyrkin SV Belyaeva OV Lapshina EA Lin DW Matsumura M Nelson PS 《The Journal of biological chemistry》2002,277(32):28909-28915
All-trans-retinoic acid is a metabolite of vitamin A (all-trans-retinol) that functions as an activating ligand for a family of nuclear retinoic acid receptors. The intracellular levels of retinoic acid in tissues are tightly regulated, although the mechanisms underlying the control of retinoid metabolism at the level of specific enzymes are not completely understood. In this report we present the first characterization of the retinoid substrate specificity of a novel short-chain dehydrogenase/reductase (SDR) encoded by RalR1/PSDR1, a cDNA recently isolated from the human prostate (Lin, B., White, J. T., Ferguson, C., Wang, S., Vessella, R., Bumgarner, R., True, L. D., Hood, L., and Nelson, P. S. (2001) Cancer Res. 61, 1611-1618). We demonstrate that RalR1 exhibits an oxidoreductive catalytic activity toward retinoids, but not steroids, with at least an 800-fold lower apparent K(m) values for NADP+ and NADPH versus NAD+ and NADH as cofactors. The enzyme is approximately 50-fold more efficient for the reduction of all-trans-retinal than for the oxidation of all-trans-retinol. Importantly, RalR1 reduces all-trans-retinal in the presence of a 10-fold molar excess of cellular retinol-binding protein type I, which is believed to sequester all-trans-retinal from nonspecific enzymes. As shown by immunostaining of human prostate and LNCaP cells with monoclonal anti-RalR1 antibodies, the enzyme is highly expressed in the epithelial cell layer of human prostate and localizes to the endoplasmic reticulum. The enzymatic properties and expression pattern of RalR1 in prostate epithelium suggest that it might play a role in the regulation of retinoid homeostasis in human prostate. 相似文献
32.
Putative "stemness" gene jam-B is not required for maintenance of stem cell state in embryonic, neural, or hematopoietic stem cells 下载免费PDF全文
Sakaguchi T Nishimoto M Miyagi S Iwama A Morita Y Iwamori N Nakauchi H Kiyonari H Muramatsu M Okuda A 《Molecular and cellular biology》2006,26(17):6557-6570
Many genes have been identified that are specifically expressed in multiple types of stem cells in their undifferentiated state. It is generally assumed that at least some of these putative "stemness" genes are involved in maintaining properties that are common to all stem cells. We compared gene expression profiles between undifferentiated and differentiated embryonic stem cells (ESCs) using DNA microarrays. We identified several genes with much greater signal in undifferentiated ESCs than in their differentiated derivatives, among them the putative stemness gene encoding junctional adhesion molecule B (Jam-B gene). However, in spite of the specific expression in undifferentiated ESCs, Jam-B mutant ESCs had normal morphology and pluripotency. Furthermore, Jam-B homozygous mutant mice are fertile and have no overt developmental defects. Moreover, we found that neural and hematopoietic stem cells recovered from Jam-B mutant mice are not impaired in their ability to self-renew and differentiate. These results demonstrate that Jam-B is dispensable for normal mouse development and stem cell identity in embryonic, neural, and hematopoietic stem cells. 相似文献
33.
Hatakeyama Wataru Lee Cliff Da Silva John Kim David M. Nagai Shigemi Kondo Hisatomo Nagai Masazumi 《International journal of peptide research and therapeutics》2021,27(2):957-965
International Journal of Peptide Research and Therapeutics - A DNA hybridization-based differential peptide display (DPD) was developed for the screening of phage peptide library to find osteogenic... 相似文献
34.
Noriko Oshima Naohiko Nakamaru Sachiko Araki Masazumi Sugimoto 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2001,129(2):75-84
In melanophores of the peppered catfish and the Nile tilapia, melanin-concentrating hormone (MCH) at low doses (<1 μM) induced pigment aggregation, and the aggregated state was maintained in the presence of MCH. However, at higher MCH concentrations (such as 1 and 10 μM), pigment aggregation was immediately followed by some re-dispersion, even in the continued presence of MCH, which led to an apparent decrease in aggregation. This pigment-dispersing activity at higher concentrations of MCH required extracellular Ca2+ ions. By contrast, medaka melanophores responded to MCH only by pigment aggregation, even at the highest concentration employed (10 μM). Since it is known that medaka melanophores possess specific receptors for α-melanophore-stimulating hormone (α-MSH), the possibility that interaction between MSH receptors and MCH at high doses in the presence of Ca2+ might cause pigment dispersion is ruled out. Cyclic MCH analogs, MCH (1–14) and MCH (5–17), failed to induce pigment dispersion, whereas they induced aggregation of melanin granules. These results suggest that another type of MCH receptor that mediates pigment dispersion is present in catfish and tilapia melanophores, and that intact MCH may be the only molecule that can bind to these receptors. Determinations of cAMP content in melanophores, which were isolated from the skin of three fish species and treated with 10 nM or 10 μM MCH, indicate that MCH receptors mediating aggregation may be coupled with Gi protein, whereas MCH receptors that mediate dispersion may be linked to Gs. The response of erythrophores, xanthophores and leucophores to MCH at various concentrations was also examined, and the results suggest that the distribution patterns of the two types of MCH receptors may differ among fish species and among types of chromatophore in the same fish. 相似文献
35.
Takeo Kuriyama Hanae Misawa Kazuyuki Miyaji Masazumi Sugimoto Masami Hasegawa 《Journal of morphology》2013,274(12):1353-1364
To provide histological foundation for studying the genetic mechanisms of color‐pattern polymorphisms, we examined light reflectance profiles and cellular architectures of pigment cells that produced striped, nonstriped, and melanistic color patterns in the snake Elaphe quadrivirgata. Both, striped and nonstriped morphs, possessed the same set of epidermal melanophores and three types of dermal pigment cells (yellow xanthophores, iridescent iridophores, and black melanophores), but spatial variations in the densities of epidermal and dermal melanophores produced individual variations in stripe vividness. The densities of epidermal and dermal melanophores were two or three times higher in the dark‐brown‐stripe region than in the yellow background in the striped morph. However, the densities of epidermal and dermal melanophores between the striped and background regions were similar in the nonstriped morph. The melanistic morph had only epidermal and dermal melanophores and neither xanthophores nor iridophores were detected. Ghost stripes in the shed skin of some melanistic morphs suggested that stripe pattern formation and melanism were controlled independently. We proposed complete‐ and incomplete‐dominance heredity models for the stripe‐melanistic variation and striped, pale‐striped, and nonstriped polymorphisms, respectively, according to the differences in pigment‐cell composition and its spatial architecture. J. Morphol. 274:1353–1364, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
36.
Nilanjana Maulik Masazumi Watanabe Daniel T. Engelman Richard M. Engelman Dipak K. Das 《Molecular and cellular biochemistry》1995,144(1):67-74
Adaptation to various forms of stress has been found to be associated with increased cellular tolerance to myocardial ischemia. In this study, the effects of myocardial adaptation to oxidative stress was examined by injecting rats with endotoxin (0.5 mg/kg) and its non-toxic derivative, lipid A (0.5 mg/kg). Both compounds exerted oxidative stress within 1 h of treatment as evidenced by enhanced malonaldehyde formation. The oxidative stress disappeared steadily and progressively with time in concert with the appearance of the induction of glutathione and antioxidative enzymes that included superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. After 24 h of endotoxin or lipid A treatment, the amount of oxidative stress and antioxidant enzyme levels were significantly lower and higher, respectively, compared to those at the baseline levels. Corroborating these results, both endotoxin and lipid A provided protection against myocardial ischemia and reperfusion injury as evidenced by significantly improved postischemic recovery of left ventricular functions. The data presented here demonstrates that a controlled amount of oxidative stress induces the expression of intracellular antioxidants that can result in enhanced myocardial tolerance to ischemia. This suggests that myocardial adaptation to oxidative stress may be a potential tool for reduction of ischemic/reperfusion injury. 相似文献
37.
Satoshi Yoshida Toshitsugu Yubisui Masazumi Takeshita 《Archives of biochemistry and biophysics》1984,232(1):296-304
Biochemical aspects of b-type cytochromes in swine cerebral microsomes were different from those of cytochrome b5 in liver microsomes, as well as the difference in absorption spectra. First, the kinetic constants, Km and Vmax, in rotenone-insensitive NADH-cytochrome c reductase activity were different from those of liver microsomes, and the activity of cerebral microsomes was higher than that of liver microsomes. Second, midpoint potentials (Em) of b-type cytochromes in cerebral microsomes were measured and compared with liver microsomal cytochrome b5. In cerebral microsomes two components of b-type cytochromes were resolved, and showed Em's of ?30 and +50 mV, respectively, in the presence of 2 mm KCN. On the other hand, the Em of liver microsomal cytochrome b5 was ?6 mV. The high-potential component of cerebral microsomal b-type cytochromes was identified as brain-b′5 [S. Yoshida, T. Yubisui, and M. Takeshita (1983)Biochem. Int. 7, 291–298] and the low-potential component as brain-b5. The significance of the difference between cerebral and liver microsomal b-type cytochromes was discussed. 相似文献
38.
Uchino K Hirano G Hirahashi M Isobe T Shirakawa T Kusaba H Baba E Tsuneyoshi M Akashi K 《Experimental cell research》2012,318(15):1799-1807
There is emerging evidence that human solid tumor cells originate from cancer stem cells (CSCs). In cancer cell lines, tumor-initiating CSCs are mainly found in the side population (SP) that has the capacity to extrude dyes such as Hoechst 33342. We found that Nanog is expressed specifically in SP cells of human gastrointestinal (GI) cancer cells. Nucleotide sequencing revealed that NanogP8 but not Nanog was expressed in GI cancer cells. Transfection of NanogP8 into GI cancer cell lines promoted cell proliferation, while its inhibition by anti-Nanog siRNA suppressed the proliferation. Immunohistochemical staining of primary GI cancer tissues revealed NanogP8 protein to be strongly expressed in 3 out of 60 cases. In these cases, NanogP8 was found especially in an infiltrative part of the tumor, in proliferating cells with Ki67 expression. These data suggest that NanogP8 is involved in GI cancer development in a fraction of patients, in whom it presumably acts by supporting CSC proliferation. 相似文献
39.
40.
Masazumi Kayama Kobayashi Makoto Mutsumi Nomura Kaichiro Sasa Takayoshi Koike 《Trees - Structure and Function》2009,23(1):145-157
Sakhalin spruce (Picea glehnii), a native species typically found in northern Japan, has been used in reforestation on hillsides exposed to strong winds.
In the reforestation areas, there are south-facing (S-slope) and northwest-facing slopes (NW-slope). Climatic conditions are
contrasting between the two slopes, with shallower snow cover on the S-slopes. We compared growth responses of the spruce
to micro-environment between the S- and NW-slopes through soil nutrients, needle longevity, water status, photosynthesis,
and nutrients in the needles. These parameters were measured in needles exposed above the snow in winter and in lower needles
protected by snow cover. High-position needles suffered from drought stress, especially in winter, and needles were shed early
in the year on both slopes. Low-position needles did not suffer from drought stress, and maintained a high photosynthetic
rate on both slopes. However, needle longevity was reduced on the S-slope, and concentrations of nitrogen, phosphorus, and
potassium in the needles decreased with needle age. Soil nutrient concentrations were low on the S-slope, which suggests that
the needles on the S-slope may remobilize nutrients from aged needles to younger needles prior to shedding. This characteristic
is probably an adaptation in Sakhalin spruce to poor soil conditions. 相似文献