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991.
992.
993.
Takayuki Miyaji Satoshi Murayama Yoshiaki Kouzuma Nobutada Kimura Michael R. Kanost Karl J. Kramer Masami Yonekura 《Insect biochemistry and molecular biology》2010,40(12):835-846
A Manduca sexta (tobacco hornworm) cysteine protease inhibitor, MsCPI, purified from larval hemolymph has an apparent molecular mass of 11.5 kDa, whereas the size of the mRNA is very large (9 kilobases). MsCPI cDNA consists of a 9,273 nucleotides that encode a polypeptide of 2,676 amino acids, which includes nine tandemly repeated MsCPI domains, four cystatin-like domains and one procathepsin F-like domain. The procathepsin F-like domain protein was expressed in Escherichia coli and processed to its active mature form by incubation with pepsin. The mature enzyme hydrolyzed Z-Leu–Arg–MCA, Z-Phe–Arg–MCA and Boc–Val–Leu–Lys–MCA rapidly, whereas hydrolysis of Suc–Leu–Tyr–MCA and Z-Arg–Arg–MCA was very slow. The protease was strongly inhibited by MsCPI, egg-white cystatin and sunflower cystatin with Ki values in the nanomolar range. When the MsCPI tandem protein linked to two MsCPI domains was treated with proteases, it was degraded by the cathepsin F-like protease. However, tryptic digestion converted the MsCPI tandem protein to an active inhibitory form. These data support the hypothesis that the mature MsCPI protein is produced from the MsCPI precursor protein by trypsin-like proteases. The resulting mature MsCPI protein probably plays a role in the regulation of the activity of endogenous cysteine proteases. 相似文献
994.
Watanabe M 《Development, growth & differentiation》2010,52(7):567-576
The pathway from the retina to the brain in mammals provides a well-defined model system for investigation of not only surviving axotomy but also axonal regeneration of injured neurons. Here I introduce our recent works on axonal regeneration in the optic nerve (OpN) of adult cats. Fibers of retinal ganglion cells (RGCs) extend beyond the crush site of OpN with injections of a macrophage stimulator (oxidized galectin-1) or a Rho kinase (ROCK) inhibitor (Y-39983 or Y-27632) while axonal extension is blocked with injection of saline. Elongation of crushed optic fibers, however, is slowed after 2 weeks. Transplantation of peripheral nerve makes RGCs regenerate their transected axons into a graft but regenerated fibers extend only a few mm in the brain. Effectiveness of combination of the drugs and treatments has to be verified in future. 相似文献
995.
996.
Masami Fujiwara 《Theoretical Ecology》2008,1(2):89-101
Chinook salmon (Oncorhynchus tshawytscha) reproduce only once in their lifetime, and their age at reproduction varies among individuals (indeterminate semelparous).
However, the factors that determine their spawning age still remain uncertain. Evidence from recent studies suggests that
individual growth and reproduction of Chinook salmon are affected by the rate of coastal upwelling, which is shown to be positively
autocorrelated between years. Therefore, the serially autocorrelated environmental is expected to play an important role in
determining their spawning age. In the present study, I demonstrate the advantage of an indeterminate maturation strategy
under a stochastic environment. I then present theoretical evidence for the advantage of adjusting the maturation probability
based on the environment they experienced and demonstrate that fisheries reduce the fitness of the strategy to delay maturation.
The results presented herein emphasize the importance of incorporating detailed life-history strategies of organisms when
undertaking population management. 相似文献
997.
The aim of the present study was to determine whether oxygen supply to non-exercised muscle during recovery following fatiguing exercise is influenced by accumulated metabolites within exercised muscle. Twelve healthy male subjects performed 2-min isometric handgrip exercise at 40% maximal voluntary contraction with their right hand and the exercise was followed by a 3-min recovery period. Muscle oxygen saturation (SmO(2)) determined by near-infrared spatially resolved spectroscopy was used as an index of oxygen supply to non-exercised muscle and was measured in biceps brachii and tibialis anterior muscles on the left side. Compared to the pre-exercise baseline level, SmO(2) in the biceps brachii muscle (SmO(2BB)) increased significantly from 30 sec to 1 min after the start of exercise, while SmO(2) in the tibialis anterior muscle (SmO(2TA)) remained stable during the initial 1 min of exercise. Both SmO(2BB) and SmO(2TA) began to decrease at about 1 min and continued to decrease thereafter. Due to the initial increase in SmO(2BB), only SmO(2TA) showed a significant decrease during exercise. During recovery, SmO(2BB) did not differ significantly from the pre-exercise baseline level, whereas SmO(2TA) remained significantly lower until about 1.5 min of recovery and then it did not differ significantly from the baseline level. In another bout, subjects performed handgrip exercise of the same intensity, but post-exercise arterial occlusion (PEAO) of the exercised muscle was imposed for 2 min immediately after the end of exercise. During PEAO, SmO(2BB) decreased significantly compared to the baseline level, whereas SmO(2TA) remained significantly lower until the end of PEAO. The significant decrease in SmO(2BB) and the prolongation of decrease in SmO(2TA) by PEAO suggests that the recovery of SmO(2) in the non-exercised arm and leg is mediated by muscle metaboreceptors. 相似文献
998.
999.
Masaru Akita Daisuke Tsutsumi Masami Kobayashi Hideo Kise 《Biotechnology letters》2001,23(22):1827-1831
Phenol and 4-substituted phenols were polymerized by H2O2 as an oxidant and hemin as a catalyst in organic/buffer mixed solvents. The chemical structures of the polymers were similar to those synthesized by the catalysis with horseradish peroxidase. Among the organic solvents used, pyridine gave the highest yield of polymer. Also, the manner of addition of H2O2 solution affected the polymer yield. 相似文献
1000.
An oxidized nucleotide affects DNA replication through activation of protein kinases in Xenopus egg lysates
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Toshinori Kai Rieko Matsunaga Masami Eguchi Hiroyuki Kamiya Hiroshi Kasai Motoshi Suzuki Shunji Izuta 《Nucleic acids research》2002,30(2):569-573
To elucidate the response to oxidative stress in eukaryotic cells, the effect of an oxidized nucleotide, 8-oxo-2′-deoxyguanosine 5′-triphosphate (8-oxo-dGTP), generated from dGTP with an active oxygen, on DNA synthesis was studied using a cell-free DNA replication system derived from Xenopus egg lysates with a single-stranded DNA template. Amounts of newly synthesized DNA were reduced according to the increasing concentration of 8-oxo-dGTP. Pulse labeling analysis revealed that 8-oxo-dGTP could delay DNA synthesis by reducing the rate of chain elongation. This delay was recovered by addition of a protein kinase inhibitor, staurosporine or bisindolylmaleimide I. These results indicate that a staurosporine- or bisindolylmaleimide I-sensitive protein kinase, such as a protein kinase C family member, may contribute to the delay of DNA synthesis by 8-oxo-dGTP. UV-irradiated single-stranded DNA also caused a delay of DNA synthesis on the undamaged template in the lysates. However, this delay was not recovered by staurosporine or bisindolylmaleimide I. Therefore, the mechanism of delay of DNA synthesis by 8-oxo-dGTP may be different from that by UV lesions. This is the first report that demonstrates an effect of an oxidized nucleotide on DNA replication in eukaryotes. 相似文献