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991.
Kawano Tomonori; Sahashi Nobuya; Takahashi Koji; Uozumi Nobuyuki; Muto Shoshi 《Plant & cell physiology》1998,39(7):721-730
Addition of salicylic acid (SA) to tobacco (Nicotiana tabacum)suspension culture immediately induced a rapid and transientgeneration of superoxide anion (O2), followed by a transientincrease in cytosolic free calcium ion concentration ([Ca2+]c).The level of SA-induced O2 was lowered by treatment withseveral scavengers of active oxygen species and a peroxidaseinhibitor, but not with an NADPH oxidase inhibitor. The SA-induced[Ca2+]c elevation was also lowered by inhibitors which effectivelylowered the O2 level. Inhibition of [Ca2+]c elevationby Ca2+ channel blockers and a Ca2+ chelator indicated thatextracellular Ca2+ was responsible for the increased [Ca2+]c.Among the several SA analogs, only compounds that actively inducedthe O2 generation also elevated [Ca2+]cIn addition, theinhibitory effects of SA analogs on catalase activity correlatedwell with their effects on the O2 generation and the[Ca2+]c elevation. SA-dependent O2 generation was shownto occur extracellularly, requiring both H2O2 and at least oneproteinaceous factor excreted from the cells. This factor wasdetermined to be a salicylhydroxamic acid-sensitive extracellularguaiacol-utilizing peroxidase.
4Present address: Isehara Research Laboratory, Kanto ChemicalCo., Inc., Suzukawa, Isehara, 259-1146 Japan. 相似文献
992.
Inhibition of intracellular hepatitis C virus replication by synthetic and vector-derived small interfering RNAs 总被引:11,自引:0,他引:11
Yokota T Sakamoto N Enomoto N Tanabe Y Miyagishi M Maekawa S Yi L Kurosaki M Taira K Watanabe M Mizusawa H 《EMBO reports》2003,4(6):602-608
Small interfering RNAs (siRNAs) efficiently inhibit gene expression by RNA interference. Here, we report efficient inhibition, by both synthetic and vector-derived siRNAs, of hepatitis C virus (HCV) replication, as well as viral protein synthesis, using an HCV replicon system. The siRNAs were designed to target the 5′ untranslated region (5′ UTR) of the HCV genome, which has an internal ribosomal entry site for the translation of the entire viral polyprotein. Moreover, the 5′ UTR is the most conserved region in the HCV genome, making it an ideal target for siRNAs. Importantly, we have identified an effective site in the 5′ UTR at which ~80% suppression of HCV replication was achieved with concentrations of siRNA as low as 2.5 nM. Furthermore, DNA-based vectors expressing siRNA against HCV were also effective, which might allow the efficient delivery of RNAi into hepatocytes in vivo using viral vectors. Our results support the feasibility of using siRNA-based gene therapy to inhibit HCV replication, which may prove to be valuable in the treatment of hepatitis C. 相似文献
993.
Hashizume R Maki Y Mizutani K Takahashi N Matsubara H Sugita A Sato K Yamaguchi S Mikami B 《The Journal of biological chemistry》2011,286(44):38691-38702
Protein glutaminase, which converts a protein glutamine residue to a glutamate residue, is expected to be useful as a new food-processing enzyme. The crystal structures of the mature and pro forms of the enzyme were refined at 1.15 and 1.73 ? resolution, respectively. The overall structure of the mature enzyme has a weak homology to the core domain of human transglutaminase-2. The catalytic triad (Cys-His-Asp) common to transglutaminases and cysteine proteases is located in the bottom of the active site pocket. The structure of the recombinant pro form shows that a short loop between S2 and S3 in the proregion covers and interacts with the active site of the mature region, mimicking the protein substrate of the enzyme. Ala-47 is located just above the pocket of the active site. Two mutant structures (A47Q-1 and A47Q-2) refined at 1.5 ? resolution were found to correspond to the enzyme-substrate complex and an S-acyl intermediate. Based on these structures, the catalytic mechanism of protein glutaminase is proposed. 相似文献
994.
Takuya Urushihata Yukako Higuchi Kazumi Sakata Tokumitsu Wakabayashi Asuka Nishino 《Bioscience, biotechnology, and biochemistry》2016,80(10):1990-1994
The effects of caffeine on salt chemotaxis learning were investigated using the nematode Caenorhabditis elegans. To estimate the degree of salt chemotaxis learning, nematodes were placed in a mixed solution of NaCl and caffeine, and then the chemotaxis index of NaCl was obtained from the nematodes placed on agar medium after pre-exposure to caffeine concentrations of 0.01, 0.1, 0.3, and 1.0%. Locomotor activity and preference behavior for caffeine were also estimated under these caffeine conditions. Nematodes pre-exposed to 0.3% caffeine showed inhibition of salt chemotaxis learning. Additional experiments indicated that nematodes showed a preference response to the middle concentration of caffeine (0.1%), with preference behavior declining in the 0.3% caffeine condition. Stable locomotor activity was observed under 0.01–0.3% caffeine conditions. These results suggest that salt chemotaxis learning with 0.3% caffeine is useful for investigating the effects of caffeine on learning in nematodes. 相似文献
995.
Yumiko Toyohira Nobuyuki Yanagihara Kouichiro Minami Susumu Ueno Yasuhito Uezono †Eiichi Tachikawa †Yukiko Kondo †Takeshi Kashimoto Futoshi Izumi 《Journal of neurochemistry》1998,70(4):1441-1447
Abstract: The aim of this study was to investigate the effect of long-term treatment with interferon (IFN)-α on the noradrenaline transporter of bovine adrenal medullary cells. Treatment of cultured adrenal medullary cells with IFN-α caused a decrease in uptake of [3 H]noradrenaline by the cells in time (4–48 h)- and concentration (300–1,000 U/ml)-dependent manners. IFN-β also inhibited [3 H]noradrenaline uptake to a lesser extent than did IFN-α, whereas IFN-γ had little effect. An anti-IFN-α antibody reduced the effect of IFN-α on [3 H]noradrenaline uptake. Saturation analysis of [3 H]noradrenaline uptake showed that the inhibitory effect of IFN-α was due to a reduction in the maximal uptake velocity ( V max ) values without altering apparent Michaelis constant ( K m ) values. Incubation of cells with IFN-α caused a translocation of protein kinase C from the soluble to the particulate fraction in the cells. The effect of IFN-α on [3 H]noradrenaline uptake was diminished in protein kinase C-down-regulated cells. Incubation of cells with IFN-α for 48 h significantly reduced the specific binding of [3 H]desipramine to crude plasma membranes isolated from cells. Scatchard analysis of [3 H]desipramine binding revealed that IFN-α decreased the maximal binding ( B max ) values without any change in the dissociation constant ( K D ) values. These findings suggest that IFN-α suppresses the function of noradrenaline transporter by reducing the density of the transporter in cell membranes through, at least in part, a protein kinase C pathway. 相似文献
996.
Virus-induced gene silencing (VIGS) is a technology that exploits an RNA-mediated antivirus defense mechanism in plants and has been shown to have great potential in plant reverse genetics. When the virus vector carries sequences of plant genes, virus infection triggers VIGS that results in the degradation of endogenous mRNAs homologous to the plant genes. The system is well established in Nicotiana benthamiana and several reliable VIGS vectors have been developed for other plant species including important agricultural crops. Here, we describe the use of VIGS technology to determine gene function and plant virus vectors for induction of VIGS in plants. 相似文献
997.
998.
Both growth and migratory history of the Pacific Ocean forms of the threespine stickleback Gasterosteus aculeatus collected in Otsuchi Bay, northeastern Japan, were examined using otolith microstructure and analysis of strontium (Sr) and
calcium (Ca) concentrations with wavelength dispersive X-ray spectrometry by an electron microprobe. Age of the juveniles
(21.6–25.9 mm in total length) examined ranged from 101 to 128 days (115 ± 8.5 days; mean ± SD), hatching being estimated
as having occurred between March and April 2001. The Sr : Ca ratios in the otoliths changed with both ontogenic development
and salinity of the habitat. The otolith Sr : Ca ratios increased gradually from 4.1 × 10−3 around the core to 7.5 × 10−3 around the edge of the otolith. The fluctuation pattern of otolith Sr : Ca ratios was different from those observed in both
freshwater resident and anadromous forms in previous studies. These results suggested that the fish sampled spend their lives
in the estuarine and sea environment without freshwater life after hatching.
Received: June 5, 2002 / Revised: September 11, 2002 / Accepted: September 24, 2002
Acknowledgments We thank Mr. K. Morita and crews of the Otsuchi Marine Research Center, Ocean Research Institute, The University of Tokyo
for their assistance in collecting specimens. This work was supported in part by Grant-in-Aid No. 13760138 from the Ministry
of Education, Culture, Sports, Science and Technology, Japan.
Correspondence to:Takaomi Arai 相似文献
999.
1000.