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21.
Tatsunori Masatani Naoto Ito Yuki Ito Keisuke Nakagawa Masako Abe Satoko Yamaoka Kota Okadera Makoto Sugiyama 《Microbiology and immunology》2013,57(7):511-517
By using a cultured neuroblastoma cell line, the present authors recently showed that the N protein of virulent rabies virus fixed strain Nishigahara (Ni), but not that of the attenuated derivative Ni‐CE, mediates evasion of induction of type I interferon (IFN). In this study, to determine whether Ni N protein indeed fulfills this function in vivo, the abilities to suppress IFN responses in the mouse brain of Ni‐CE and the virulent chimeric virus CE(NiN), which has the N gene from Ni in the genetic background of Ni‐CE, were compared. It was demonstrated that CE(NiN) propagates and spreads more efficiently than does Ni‐CE in the brain and that IFN response in brains infected with CE(NiN) is weaker than in those infected with Ni‐CE. It was also shown that amino acids at positions 273 and 394 in the N protein, which are known as pathogenic determinants, affect the ability of the viruses to suppress IFN response in the brain. These findings strongly suggest that, in the brain, rabies virus N protein plays important roles in evasion of innate immune responses and thereby in efficient propagation and spread of virus leading to lethal outcomes of infection. 相似文献
22.
Keisuke Ueda Chieko Kimura-Sakiyama Tomoki Aihara Masao Miki Toshiaki Arata 《Biophysical journal》2013
To identify the interaction sites of Tm, we measured the rotational motion of a spin-label covalently bound to the side chain of a cysteine that was genetically incorporated into rabbit skeletal muscle tropomyosin (Tm) at positions 13, 36, 146, 160, 174, 190, 209, 230, 271, or 279. Most of the Tm residues were immobilized on actin filaments with myosin-S1 bound to them. The residues in the mid-portion of Tm, namely, 146, 174, 190, 209, and 230, were mobilized when the troponin (Tn) complex bound to the actin-Tm-S1 filaments. The addition of Ca2+ ions partially reversed the Tn-induced mobilization. In contrast, residues at the joint region of Tm, 13, 36, 271, and 279 were unchanged or oppositely changed. All of these changes were detected using a maleimide spin label and less obviously using a methanesulfonate label. These results indicated that Tm was fixed on thin filaments with myosin bound to them, although a small change in the flexibility of the side chains of Tm residues, presumably interfaced with Tn, actin and myosin, was induced by the binding of Tn and Ca2+. These findings suggest that even in the myosin-bound (open) state, Ca2+ may regulate actomyosin contractile properties via Tm. 相似文献
23.
Yoshiyuki Inoue Keiko Nakahara Keisuke Maruyama Yoshiharu Suzuki Yujiro Hayashi Kenji Kangawa Noboru Murakami 《Biochemical and biophysical research communications》2013,430(1):278-283
In the present study using rats, we demonstrated that central and peripheral administration of des-acyl ghrelin induced a decrease in the surface temperature of the back, and an increase in the surface temperature of the tail, although the effect of peripheral administration was less marked than that of central administration. Furthermore, these effects of centrally administered des-acyl ghrelin could not be prevented by pretreatment with [D-Lys3]-GHRP-6 GH secretagogue receptor 1a (GHS-R1a) antagonists. Moreover, these actions of des-acyl ghrelin on body temperature were inhibited by the parasympathetic nerve blocker methylscopolamine but not by the sympathetic nerve blocker timolol. Using immunohistochemistry, we confirmed that des-acyl ghrelin induced an increase of cFos expression in the median preoptic nucleus (MnPO). Additionally, we found that des-acyl ghrelin dilated the aorta and tail artery in vitro. These results indicate that centrally administered des-acyl ghrelin regulates body temperature via the parasympathetic nervous system by activating neurons in the MnPO through interactions with a specific receptor distinct from the GHS-R1a, and that peripherally administered des-acyl ghrelin acts on the central nervous system by passing through the blood–brain barrier, whereas it exerts a direct action on the peripheral vascular system. 相似文献
24.
Keisuke Nakatani Haruto Ishikawa Shigetoshi Aono Yasuhisa Mizutani 《Biochemical and biophysical research communications》2013
The heme detoxification protein of the malaria parasite Plasmodium falciparum is involved in the formation of hemozoin, an insoluble crystalline form of heme. Although the disruption of hemozoin formation is the most widely used strategy for controlling the malaria parasite, the heme-binding properties of heme detoxification protein are poorly characterized. In this study, we established a method for the expression and purification of the non-tagged protein and characterized heme-binding properties. The spectroscopic features of non-tagged protein differ from those of the His-tagged protein, suggesting that the artificial tag interferes with the properties of the recombinant protein. The purified recombinant non-tagged heme detoxification protein had two heme-binding sites and exhibited a spectrum typical of heme proteins. A mechanism for hemozoin formation is proposed. 相似文献
25.
Keisuke Yoshikawa Yoshihiro Kita Ayako Furukawa Noriko Kawamura Sanae Hasegawa-Ishii Yoichi Chiba Shiro Takei Kei Maruyama Takao Shimizu Atsuyoshi Shimada 《Prostaglandins, leukotrienes, and essential fatty acids》2013,88(5):373-381
Excitotoxicity is involved in neurodegenerative conditions. We investigated the pathological significance of a surge in prostaglandin production immediately after kainic acid (KA) administration [initial phase], followed by a sustained moderate elevation in prostaglandin level [late phase] in the hippocampus of juvenile rats. Numerous pyknotic hippocampal neurons were observed 72 h after KA treatment; this number remained elevated on days 10 and 30. Gross hippocampal atrophy was observed on days 10 and 30. Pre-treatment with indomethacin ameliorated neuronal death on days 10 and 30, and prevented hippocampal atrophy on day 30. Microglial response was moderated by the indomethacin pre-treatment. Blockade of only late-phase prostaglandin production by post-treatment with indomethacin ameliorated neuronal death on day 30. These findings suggest a role for initial-phase prostaglandin production in chronic progressive neuronal death, which is exacerbated by late-phase prostaglandin production. Blockade of prostaglandin production has therapeutic implications in preventing long-term neurological sequelae following excitotoxic brain damage. 相似文献
26.
Biochemical Characterization of Lipoxygenase Lacking Mutants,L-l-less,L-2-less,and L-3-less Soybeans
Keisuke Kitamura 《Bioscience, biotechnology, and biochemistry》2013,77(9):2339-2346
In this paper, lipoxygenase lacking mutants were characterized in comparison with normal soybeans. The three lipoxygenase isozymes (L-l, L-2, and L-3) in crude seed extracts of normal soybeans were resolved clearly by an improved SDS-polyacrylamide gel electrophoresis. As expected, the three mutant types, L-l-less (P. I. 408251 and 133226), L-2-less (P. I. 86023), and L-3 less (Wasenatsu and Ichigowase) soybeans did not give L-l, L-2, and L-3 protein bands, respectively on a single dimension SDS gel.An anti L-2 serum obtained from a rabbit reacted not only with the purified L-2 protein, but also partially with the purified L-l and L-3 proteins. By double immunodiffusion and immuno-disc gel electrofocusing analyses using the anti L-2 serum, L-l, L-2, and L-3 isozymes could not be detected in crude seed extracts from P.I. 408251, P. I. 86023, and Wasenatsu soybeans, respectively.Three lipoxygenase activity peaks (L-l, L-2, and L-3 enzyme peaks) and a small unknown activity peak eluted right after the L-l peak were fractionated by DEAE-Sephacel column chromatography of crude seed extracts of Raiden (normal) soybeans. The chromatographic analyses have demonstrated that both the L-l and the unknown enzyme activities disappear completely in the L-l-less type soybean seeds, and that the L-2 and L-3 enzyme activities disappear completely in P. I. 86023 and the L-3-less type soybean seeds, respectively. 相似文献
27.
28.
Hiroaki Takahashi Yasunori Nara Katura Tuzimura 《Bioscience, biotechnology, and biochemistry》2013,77(12):2493-2494
Fluctuations of pungent principles of hot pepper fruits (capsaicinoid), chlorophylls, carotenoid, and fresh fruit weight in Capsicum annuum var. annuum cv. Karayatsubusa at different growth stages after flowering were examined. Capsaicinoid was first detected 20 days after flowering, and reached maximal level around 40 days after flowering, then later decreased gradually. The capsaicinoid composition did not show any appreciable change throughout the stages after flowering. CAP and DC were the major components in all of the stages examined. By using radioisotopic technique, it was found that the main formation and accumulation sites of capsaicinoid are in the placenta of the fruits. 相似文献
29.
Keisuke Kitamura Kazuyoshi Okubo Kazuo Shibasaki 《Bioscience, biotechnology, and biochemistry》2013,77(5):1083-1085
Kinetics of the acyl transfer catalyzed by Xanthomonas α-amino acid ester hydrolase was studied. The enzyme hydrolyzed d-α-phenylglycine methyl ester (d-PG-OMe) to give equimolar amounts of d-α-phenylglycine and methanol. With d-PG-OMe as an acyl donor and 7-amino-3-deacetoxy-cephalosporanic acid (7-ADCA) as an acyl acceptor, the enzyme transferred the acyl group from d-PG-OMe to 7-ADCA in competition with water. The addition of amine nucleophiles (7-ADCA and 6-aminopenicillanic acid) decreased the molecular activity (ko) of the enzyme-catalyzed hydrolysis of d-PG-OMe, whereas it did not alter the Michaelis constant (KM), and plots of l/ko against the initial concentration of a nucleophile (no) gave a straight line. These results support the assumptions that the overall process for hydrolysis and acyl transfer proceeds through a common acyl-enzyme intermediate, that the acylation step of the enzyme is rate-limiting, and that the transfer competes with the hydrolysis of the acyl donor. 相似文献
30.
Takashi Nara Isao Kawamoto Masanaru Misawa Shukuo Kinoshita 《Bioscience, biotechnology, and biochemistry》2013,77(8):956-962
Brevibacterium insectiphilium KY 3446 (Steinhous, Breed AHU 1401) was found to accumulate IMP from hypoxanthine and UMP from uracil, respectively. This strain is thus considered to present the fourth example in salvage-type fermentation, in addition to Micrococcus sodonensis, Arthrobacter citreus and Brevibacterium ammoniagenes reported previously.IMP from adenine and UMP from cytosine were also produced by KY 3446, respectively. Further, the addition of inosine and adenosine instead of the bases also caused IMP accumulation.This strain grew well on sucrose medium, and produced IMP and UMP in higher yields on sucrose than on glucose medium.Excessive amounts of Mn2+ stimulated growth, but markedly inhibited IMP production. The optimal concentration of Mn2+ for IMP accumulation induced morphogenetic alterations from normal and small to abnormal and large cells. 相似文献