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81.
Kuzumoto M Takeuchi A Nakai H Oka C Noma A Matsuoka S 《Progress in biophysics and molecular biology》2008,96(1-3):171-186
To quantitatively understand intracellular Na+ and Cl− homeostasis as well as roles of Na+/K+ pump and cystic fibrosis transmembrane conductance regulator Cl− channel (ICFTR) during the β1-adrenergic stimulation in cardiac myocyte, we constructed a computer model of β1-adrenergic signaling and implemented it into an excitation-contraction coupling model of the guinea-pig ventricular cell, which can reproduce membrane excitation, intracellular ion changes (Na+, K+, Ca2+ and Cl−), contraction, cell volume, and oxidative phosphorylation. An application of isoproterenol to the model cell resulted in the shortening of action potential duration (APD) after a transient prolongation, the increases in both Ca2+ transient and cell shortening, and the decreases in both Cl− concentration and cell volume. These results are consistent with experimental data. Increasing the density of ICFTR shortened APD and augmented the peak amplitudes of the L-type Ca2+ current (ICaL) and the Ca2+ transient during the β1-adrenergic stimulation. This indirect inotropic effect was elucidated by the increase in the driving force of ICaL via a decrease in plateau potential. Our model reproduced the experimental data demonstrating the decrease in intracellular Na+ during the β-adrenergic stimulation at 0 or 0.5 Hz electrical stimulation. The decrease is attributable to the increase in Na+ affinity of Na+/K+ pump by protein kinase A. However it was predicted that Na+ increases at higher beating rate because of larger Na+ influx through forward Na+/Ca2+ exchange. It was demonstrated that dynamic changes in Na+ and Cl− fluxes remarkably affect the inotropic action of isoproterenol in the ventricular myocytes. 相似文献
82.
Minoru Okuma Yukio Yamori Kiyoe Ohta Haruto Uchino 《Prostaglandins & other lipid mediators》1979,17(1):1-7
Activities of aortae to produce prostaglandin (PG) I2-like substance in stroke-prone spontaneously hypertensive rats (SHRSP), stroke-resistant SHR (SHRSR) and normotensive control rats from the Wistar-Kyoto (WK) colony were compared. PGI2-like substance was produced by the incubation of the aortic ring in pH 9.0 borate-buffered saline and the amount produced was estimated by comparison of its anti-aggregatory activity with that produced by known amounts of the sodium salt of synthetic PGI2. Before the development of stroke, amounts of this substance generated in SHRSP and SHRSR were significantly higher than those in WK rats (p<0.01 and p<0.02, respectively). Remarkably reduced capacity to generate PGI2-like substance was observed in some SHRSP after the development of stroke. 相似文献
83.
Shogo Matsumoto Akira Isogai Akinori Suzuki 《Bioscience, biotechnology, and biochemistry》2013,77(9):2401-2403
Two types of glycerol dehydrogenase (GDH) were found on DEAE-cellulose column chromatography of cell-free extracts of methylotrophic yeasts. One type, designated as GDH I, showed only the reductive activity which was detected in the reaction system containing dihydroxyacetone and NADH, at pH 6.0. The other type, designated as GDH II, showed the oxidative activity which was detected in the system containing glycerol and NAD +, at pH 9.0, together with the reductive activity.Candida boidinii No. 2201, which possesses the phosphorylative pathway for glycerol dissimilation, had only GDH I when grown on glycerol or methanol as the carbon source. Hansenula ofunaensis, which has the oxidative pathway, had both GDH I and GDH II when grown on glycerol, but only GDH I when grown on methanol. Hansenula polymorpha Dl-1, which has both pathways, had both GDH I and GDH II when grown on glycerol or methanol. 相似文献
84.
Yuzuru Mikami Sen Feng Yu Katsukiyo Yazawa Kazutaka Fukushima Akio Maeda Jun Uno Kiyoshi Terao Naoki Saito Akinori Kubo Ken -ichiro Suzuki 《Mycopathologia》1990,112(2):113-118
During our studies on toxic substances from clinically isolated Nocarida, a new isolate identified as Nocardia otitidiscaviarum from cutaneous nocardiosis was found to produce a toxic substance called HS-6 that had strong in vitro as well as in vivo toxicity. The mouse intraperitoneal LD50 value was 1.25 mg/kg and the ED50 value for L1210 cultured cells was 0.3 ng/ml. The structure of HS-6 was determined and found to belong to the 16-membered macrocyclic group with a molecular formula of C43H68O12. HS-6 also showed activity against pathogenic fungi such as Cryptococcus neoformans. 相似文献
85.
Tomohiro Kiyosue Jiro Nakayama Shinobu Satoh Akira Isogai Akinori Suzuki Hiroshi Kamada Hiroshi Harada 《Planta》1992,186(3):337-342
ECP31, an embryogenic-cell protein from carrot (Daucus carota L.), was purified by sequential column-chromatographic steps and digested by V8 protease on a nitrocellulose membrane. The resultant peptides were separated by reverse-phased column chromatography and sequenced. The sequences obtained were 70–80% homologous to those of a late-embryogenesis-abundant protein (D34) from cotton (Baker et al, 1988, Plant Mol. Biol. 11, 227–291). The level of ECP31 in somatic embryos of carrot was increased by treatment of the embryos with 3.7 · 10–6 M abscisic acid (ABA) for 48 h, and there was no change in this enhanced level for up to 192 h in the presence of ABA. No similar enhancing effect of ABA was observed on the level of ECP31 in embryogenic callus or segments of carrot hypocotyls. In an immunohistochemical analysis, ECP31 was found in epidermal tissue and in the vascular system of ABA-treated somatic embryos.Abbreviations ABA
abscisic acid
- 2,4-D
2,4-dichlorophenoxyacetic acid
- LEA protein
late-embryogenesis-abundant protein
To whom correspondence should be addressedThis work was supported in part by a grant-in-aid for Special Research in Priority Areas (Project No. 02242102) from the Ministry of Education, Science and Culture, Japan, and by Special Coordination Funds of the Science and Technology Agency of the Japanese Government. 相似文献
86.
Isogai Akira; Takayama Seiji; Shiozawa Hideyuki; Tsukamoto Chise; Kanbara Takeshi; Hinata Kokichi; Okazaki Keiichi; Suzuki Akinori 《Plant & cell physiology》1988,29(8):1331-1336
S-Glycoproteins (S-locus-specific glycoproteins) in Brassicaspecies are present only in stigmas and thought to play an importantrole in self-incompatibility system. The stigma extract containsalso several other glycoproteins reacting with the antiserumto S-glycoproteins, among which some glycoproteins from S8S8-and S9S9-homozygotes have the same pI value. Both of the glycoproteinswhich were tentatively termed NS8- and NS8S9-glycoproteins,respectively, were isolated and analyzed. Those were revealedto be identical. Its amino acid sequence was homologous withthe S-glycoproteins in Brassica species. The NS-glycoproteinswere expressed at the same time and only in stigma as S-glycoproteins. (Received July 19, 1988; Accepted September 7, 1988) 相似文献
87.
88.
Inositol 1,4,5‐trisphosphate receptor (InsP3R) is an intracellular Ca2+‐release channel activated by binding of inositol 1,4,5‐trisphosphate (InsP3) to the InsP3 binding core (IBC). Structural change in the IBC upon InsP3 binding is the key process in channel pore opening. In this study, we performed molecular dynamics (MD) simulations of the InsP3‐free form of the IBC, starting with removal of InsP3 from the InsP3‐bound crystal structure, and obtained the structural ensemble of the InsP3‐free form of the IBC. The simulation revealed that the two domains of the IBC largely fluctuate around the average structure with the hinge angle opened 17° more than in the InsP3‐bound form, and the twist angle rotated by 45°, forming interdomain contacts that are different from those in the bound form. The InsP3 binding loop was disordered. The InsP3‐free form thus obtained was reproduced four times in simulations started from a fully extended configuration of the two domains. Simulations beginning with the fully extended form indicated that formation of a salt bridge between Arg241 and Glu439 is crucial for stabilizing the closed form of the two domains. Mutation of Arg241 to Gln prevented formation of the compact structure by the two domains, but the fully flexible domain arrangement was maintained. Thus, the Arg241‐Glu439 salt bridge determines the flexibility of the InsP3‐free form of the IBC.Proteins 2013; 81:1699–1708. © 2013 Wiley Periodicals, Inc. 相似文献
89.
Kawaguchi A Asano H Matsushima K Wada T Yoshida S Ichida S 《Neurochemical research》2007,32(9):1469-1475
It is well known that morphological and functional changes during neural differentiation sometimes accompany the expression
of various voltage-gated ion channels. In this work, we investigated whether the enhancement of sodium current in differentiated
neuroblastoma × glioma NG108-15 cells treated with dibutyryl cAMP is related to the expression of voltage-gated sodium channels.
The results were as follows. (1) Sodium current density on peak voltage in differentiated cells was significantly enhanced
compared with that in undifferentiated cells, as detected by the whole-cell patch clamp method. The steady-state inactivation
curve in differentiated cells was similar to that for undifferentiated cells, but a hyperpolarized shift in the activation
curve for differentiated cells was observed. The sodium currents of differentiated and undifferentiated cells were completely
inhibited by 10−7 M tetrodotoxin (TTX). (2) The only NaV mRNA with an increased expression level during neuronal differentiation was that for NaV1.7, as observed by real-time PCR analysis. (3) The increase in the level of NaV1.7 α subunit expression during neuronal differentiation was also observed by immunocytochemistry; in particular, the localization
of NaV1.7 α subunits on the soma, varicosities and growth cone was significant. These results suggest that the enhancement of TTX-sensitive
sodium current density in differentiated NG108-15 cells is mainly due to the increase in the expression of the TTX-sensitive
voltage-gated Na+ channel, NaV1.7. 相似文献
90.
Koji Kawata Atsushi Iwai Daisuke Muramatsu Shiho Aoki Hirofumi Uchiyama Mitsuyasu Okabe Sumio Hayakawa Akinori Takaoka Tadaaki Miyazaki 《PloS one》2015,10(4)
A β-glucan produced by Aureobasidium pullulans (AP-PG) is consisting of a β-(1,3)-linked main chain with β-(1,6)-linked glucose side residues. Various β-glucans consisting of β-(1,3)-linked main chain including AP-PG are believed to exhibit anti-tumor activities, and actually, anti-tumor activities of AP-PG in mice have been demonstrated. In this study, we demonstrate that stimulation with AP-PG induces TRAIL expression in mouse and human macrophage-like cell lines. TRAIL is known to be a cytokine which specifically induces apoptosis in transformed cells, but not in untransformed cells. The expression of TRAIL mRNA after stimulation with AP-PG was increased in RAW264.7 cells, Mono Mac 6 cells, and macrophage-differentiated THP-1 cells. The mRNA expression of TNF-α and FasL is only weakly increased after stimulation with AP-PG. The induction activity of TRAIL by curdlan, a bacterial β-glucan, was very similar to that by AP-PG in RAW264.7 cells, but weaker in macrophage-differentiated THP-1 cells. Activation of caspases was found in HeLa cells after treatment with the supernatant of cultured medium from AP-PG-stimulated Mono Mac 6 cells, and was inhibited by the anti-TRAIL neutralizing antibody. These findings suggest that the stimulation with AP-PG effectively induces TRAIL in macrophages, and that it may be related to apoptosis induction of tumor cells. 相似文献