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951.
Shikazono N Tanaka A Kitayama S Watanabe H Tano S 《Radiation and environmental biophysics》2002,41(2):159-162
To clarify the effect of heavy ions in plants, dry seeds of Arabidopsis were irradiated with carbon, neon, and argon ions with various linear energy transfer (LET) values. The relative biological effectiveness (RBE) for lethality peaked at LET values over 350 keV/microns for neon and argon ions. This LET giving the peak RBE was higher than the LET of 100-200 keV/microns which was reported to have a maximum RBE for other types of cells, such as mammalian cells. Furthermore, sterility showed a higher RBE at an LET of 354 keV/microns with neon ions than that at an LET of 113 keV/microns with carbon ions. Lethality and sterility are both considered to be caused by damage to DNA. The results indicate that the LET having a maximum of RBE for lethality is higher in Arabidopsis seeds than in other unicellular systems. The most likely explanation for this shift of LET is that the DNA in dry seeds has a different chemical environment and/or hydration state than the DNA in cells in culture. 相似文献
952.
Association of a polymorphism of the CC chemokine receptor-2 gene with bone mineral density 总被引:2,自引:0,他引:2
The possible association of the 190G-->A (Val64Ile) polymorphism of the CC chemokine receptor-2 gene (CCR2) with bone mineral density (BMD) was examined in 2215 subjects (1125 men, 1090 women), all of whom were community-dwelling individuals aged 40 to 79 years. Among men aged < 60 years, BMD for the distal radius, lumbar spine, or Ward's triangle was significantly greater in those with the AA genotype than in those with the GG or GA genotypes. For postmenopausal women, BMD for the distal radius or femoral neck was significantly greater in those with the AA genotype than in those with the GG or GA genotypes. In contrast, for men aged > or =60 years and for premenopausal women, BMD was not associated with the CCR2 genotype. These results suggest that CCR2 may be a new candidate for a susceptibility locus for bone mass in middle-aged men and postmenopausal women. 相似文献
953.
Insulin-like growth factor I receptor is expressed at normal levels in Nijmegen breakage syndrome cells 总被引:1,自引:0,他引:1
Watanabe H Yu D Sasaki T Shibuya H Hosoi Y Asada M Komatsu K Miura M 《Biochemical and biophysical research communications》2002,295(1):62-66
Curcumin (diferuloylmethane) is a major component of food flavoring turmeric (Curcuma longa), and has been reported to be anticarcinogenic and anti-inflammatory. Although curcumin was shown to have antioxidant properties, its exact antioxidant nature has not been fully investigated. In this report we have investigated the possible antioxidant properties of curcumin using EPR spectroscopic techniques. Curcumin was found to inhibit the (1)O(2)-dependent 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) formation in a dose-dependent manner. (1)O(2) was produced in a photosensitizing system using rose bengal as sensitizer, and was detected as TEMP-(1)O(2) adducts by electron paramagnetic resonance (EPR) spectroscopic techniques using TEMP as a spin-trap. Curcumin at 2.75 microM caused 50% inhibition of TEMP-(1)O(2) adduct formation. However, curcumin only marginally inhibited (24% maximum at 80 microM) reduction of ferricytochrome c in a xanthine-xanthine oxidase system demonstrating that it is not an effective superoxide radical scavenger. Additionally, there was minor inhibition of DMPO-OH adduct formation by curcumin (solubilized in ethanol) when an ethanol control was included in the EPR spin-trapping study, suggesting that curcumin may not be an effective hydroxyl radical scavenger. Together these data demonstrate that curcumin is able only to effectively quench singlet oxygen at very low concentration in aqueous systems. 相似文献
954.
Oka M Hitomi T Okada T Nakamura Si S Nagai H Ohba M Kuroki T Kikkawa U Ichihashi M 《Biochemical and biophysical research communications》2002,294(5):1109-1113
The regulation of phospholipase D1 (PLD1), which has been shown to be activated by protein kinase C (PKC) alpha, was investigated in the human melanoma cell lines. In G361 cell line, which lacks PKCalpha, 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced PLD activation was potentiated by introducing PKCalpha by the adenovirus vector. The kinase-negative PKCalpha elevated TPA-induced PLD activity less significantly than the wild type. A PKC specific inhibitor GF109203X lowered PLD activation in the cells expressing PKCalpha, but did not prevent PLD potentiation induced by the kinase-negative PKCalpha. Expression of PKCbetaII and the kinase-negative PKCbetaII enhanced TPA-stimulated PLD activity moderately in MeWo cell line, in which PKCbetaII is absent. Furthermore, the TPA treatment increased the association of PKCalpha, PKCbetaII, and their kinase-negative mutants with PLD1 in melanoma cells. These results indicate that PLD1 is dually regulated through phosphorylation as well as through the protein-protein interaction by PKCalpha, and probably by PKCbetaII, in vivo. 相似文献
955.
Tsuboi D Qadota H Kasuya K Amano M Kaibuchi K 《Biochemical and biophysical research communications》2002,292(3):697-701
To screen for important molecules that interact with a gene of interest in Caenorhabditis elegans (C. elegans), we established a novel functional screening system using the yeast two-hybrid system with the RNA interference technique. Our screening system makes it possible to identify the molecular machinery involved in the function of a gene of interest starting with the cDNA of this gene. As a model case, we examined the molecular machinery involved in the function of GEX-3, an essential factor of tissue morphogenesis. We identified many interacting molecules by yeast two-hybrid screening and could detect some functional interactions using this novel functional screening system. 相似文献
956.
Tamada H Sakashita E Shimazaki K Ueno E Hamamoto T Kagawa Y Endo H 《Biochemical and biophysical research communications》2002,297(1):96-104
Neural RNA recognition motif (RRM)-type RNA-binding proteins play essential roles in neural development. To search for a new member of neural RRM-type RNA-binding protein, we screened rat cerebral expression library with polyclonal antibody against consensus RRM sequences. We have cloned and characterized a rat cDNA that belongs to RRM-type RNA-binding protein family, which we designate as drb1. Orthologs of drb1 exist in human and mouse. The predicted amino acid sequence reveals an open reading frame of 476 residues with a corresponding molecular mass of 53kDa and consists of four RNA-binding domains. drb1 gene is specifically expressed in fetal (E12, E16) rat brain and gradually reduced during development. In situ hybridization demonstrated neuron-specific signals in fetal rat brain. RNA-binding assay indicated that human Drb1 protein possesses binding preference on poly(C)RNA. These results indicate that Drb1 is a new member of neural RNA-binding proteins, which expresses under spatiotemporal control. 相似文献
957.
Yanagita M Shimabukuro Y Nozaki T Yoshimura N Watanabe J Koide H Terakura M Saho T Takedachi M Jang MH Kiyono H Murakami S 《Biochemical and biophysical research communications》2002,297(2):329-334
To investigate the biological activity of epithelial cells in view of host defense, we analyzed the mRNA expression of inducible NOS (iNOS) as well as NO production by human gingival epithelial cells (HGEC) stimulated with IL-15. RT-PCR analysis revealed that HGEC expressed IL-15 receptor alpha-chain mRNA. In addition, stimulation with IL-15 enhanced iNOS expression by HGEC through an increase of both mRNA and protein levels. Moreover, IL-15 up-regulated the production of NO(2)(-)/NO(3)(-), a NO-derived stable end product, from HGEC. The enhanced NO production by IL-15 was inhibited by AMT, an iNOS-specific inhibitor. These results suggest that IL-15 is a potent regulator of iNOS expression by HGEC and involved in innate immunity in the mucosal epithelium. 相似文献
958.
Horiuchi T Nishimukai H Okiura T Nishimura K Nishizaka H Kojima T Tsukamoto H Hayashi K Harada M 《Biochemical and biophysical research communications》2002,298(3):450-455
Complement C7 is one of the components of membrane attack complex (MAC) generated by the terminal complement cascade. C7 protein is polymorphic and most of its polymorphisms have been identified using isoelectric focusing (IEF), which detects protein charge differences. To date, the molecular bases of the polymorphisms detected by IEF have not been determined. In this paper, we describe the structural bases of two C7 IEF-detected polymorphisms, C7*3 and C7*4, both of which are common in Asian populations. C7*3 resulted from substitution of cysteine (Cys) at amino acid residue 106 by charged arginine (Arg; C106R), while charged lysine (Lys) at amino acid residue 398 was replaced by neutral glutamine (Gln; K398Q) in C7*4. As C7*3 is hypomorphic, it is important to study its possible associations with diseases such as immunological disorders and infections. We present genetic bases for this C7 polymorphism, which we determined using polymerase chain reaction (PCR)-based genotyping, a simple and accurate method suitable for large-scale studies. 相似文献
959.
960.
Bovine immature oocytes acquire developmental competence during meiotic arrest in vitro 总被引:9,自引:0,他引:9
To test the hypothesis that oocytes require time to acquire developmental competence during meiotic arrest, we investigated the effects of butyrolactone I (BL I), a potent and specific inhibitor of cyclin-dependent kinase, on the developmental competence of bovine oocytes after in vitro fertilization (IVF) following release from meiotic arrest. In the present study, 4 culture conditions were used: addition of BSA or fetal bovine serum (FBS) under 2 oxygen tensions (5% vs. 20%) during meiotic arrest with 100-microM BL I. The developmental competence to the blastocyst stage was higher (P < 0.01) in oocytes that were arrested in FBS-supplemented medium under 5% O2 (37%) than in oocytes that were arrested under other conditions (5%-24%) or that matured directly following follicle aspiration (23%). The time course of nuclear maturation of BL I-treated oocytes was also examined. The results demonstrated that oocytes treated with BL I start germinal vesicle (GV) breakdown and reach the metaphase II stage 5.5-6.0 h earlier than nonarrested oocytes. The developmental rates to the blastocyst stage of BL I-treated oocytes matured for 15.5 and 21 h were higher (P < 0.05) than those of nontreated oocytes matured for 21 and 26.5 h, respectively. These results demonstrate that bovine immature oocytes, which were arrested at the GV stage with BL I in FBS-supplemented medium under low oxygen tension, acquire higher developmental competence during meiotic arrest. 相似文献