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91.
Uchida H Kondo D Yamashita A Nagaosa Y Sakurai T Fujii Y Fujishiro K Aisaka K Uwajima T 《FEMS microbiology letters》2003,229(1):31-36
An aldehyde oxidase, which oxidizes various aliphatic and aromatic aldehydes using O(2) as an electron acceptor, was purified from the cell-free extracts of Pseudomonas sp. KY 4690, a soil isolate, to an electrophoretically homogeneous state. The purified enzyme had a molecular mass of 132 kDa and consisted of three non-identical subunits with molecular masses of 88, 39, and 18 kDa. The absorption spectrum of the purified enzyme showed characteristics of an enzyme belonging to the xanthine oxidase family. The enzyme contained 0.89 mol of flavin adenine dinucleotide, 1.0 mol of molybdenum, 3.6 mol of acid-labile sulfur, and 0.90 mol of 5'-CMP per mol of enzyme protein, on the basis of its molecular mass of 145 kDa. Molecular oxygen served as the sole electron acceptor. These results suggest that aldehyde oxidase from Pseudomonas sp. KY 4690 is a new member of the xanthine oxidase family and might contain 1 mol of molybdenum-molybdpterin-cytosine dinucleotide, 1 mol of flavin adenine dinucleotide, and 2 mol of [2Fe-2S] clusters per mol of enzyme protein. The enzyme showed high reaction rates toward various aliphatic and aromatic aldehydes and high thermostability. 相似文献
92.
NRSF regulates the fetal cardiac gene program and maintains normal cardiac structure and function 总被引:1,自引:0,他引:1
93.
Meacci E Cencetti F Donati C Nuti F Farnararo M Kohno T Igarashi Y Bruni P 《Biochimica et biophysica acta》2003,1633(3):133-142
The bioactive lipid sphingosine 1-phosphate (S1P) is known to exert powerful biological effects through the interaction with various members of the endothelial differentiation gene (EDG) receptor family, recently renamed S1P receptors. In the present study, evidence is provided that differentiation of C2C12 myoblasts into myotubes was accompanied by profound changes of EDG/S1P receptor expression. Indeed, in differentiated cells a significant increase of EDG3/S1P3 together with a large decrease of EDG5/S1P2 expression at mRNA as well as protein level was detected. Moreover, S1P was capable to initiate the signalling pathways downstream to cytosolic Ca(2+) increase in myotubes, similarly to that observed in myoblasts, whereas the signalling of the bioactive lipid to phospholipase D (PLD), but not that of bradykinin (BK) or lysophosphatidic acid (LPA), was found impaired in differentiated cells. Intriguingly, overexpression of EDG5/S1P2, but not EDG1/S1P1 or EDG3/S1P3, potentiated the efficacy of S1P to stimulate PLD, strongly suggesting a role for EDG5/S1P2 in the signalling to PLD. This view was also supported by the marked reduction of S1P-induced PLD activity in myoblasts loaded with antisense oligodeoxyribonucleotides (ODN) to EDG5/S1P2. Furthermore, overexpression of EDG5/S1P2 rescued the coupling of S1P signalling to PLD in C2C12 myotubes. Experimental evidence here provided supports the notion that EDG5/S1P2 plays a dominant role in the coupling of S1P to PLD in myoblasts and that the down-regulation of the receptor subtype is responsible for the specific uncoupling of S1P signalling to PLD in myotubes. 相似文献
94.
Yoshihiko Kakinuma Tsuyoshi Akiyama Kayo Okazaki Mikihiko Arikawa Tatsuya Noguchi Takayuki Sato 《PloS one》2012,7(11)
Background
In our previous study, we established the novel concept of a non-neuronal cardiac cholinergic system–cardiomyocytes produce ACh in an autocrine and/or paracrine manner. Subsequently, we determined the biological significance of this system–it played a critical role in modulating mitochondrial oxygen consumption. However, its detailed mechanisms and clinical implications have not been fully investigated.Aim
We investigated if this non-neuronal cardiac cholinergic system was upregulated by a modality other than drugs and if the activation of the system contributes to favorable outcomes.Results
Choline acetyltransferase knockout (ChAT KO) cells with the lowest cellular ACh levels consumed more oxygen and had increased MTT activity and lower cellular ATP levels compared with the control cells. Cardiac ChAT KO cells with diminished connexin 43 expression formed poor cell–cell communication, evidenced by the blunted dye transfer. Similarly, the ChAT inhibitor hemicholinium-3 decreased ATP levels and increased MTT activity in cardiomyocytes. In the presence of a hypoxia mimetic, ChAT KO viability was reduced. Norepinephrine dose-dependently caused cardiac ChAT KO cell death associated with increased ROS production. In in vivo studies, protein expression of ChAT and the choline transporter CHT1 in the hindlimb were enhanced after ischemia-reperfusion compared with the contralateral non-treated limb. This local effect also remotely influenced the heart to upregulate ChAT and CHT1 expression as well as ACh and ATP levels in the heart compared with the baseline levels, and more intact cardiomyocytes were spared by this remote effect as evidenced by reduced infarction size. In contrast, the upregulated parameters were abrogated by hemicholinium-3.Conclusion
The non-neuronal cholinergic system plays a protective role in both myocardial cells and the entire heart by conserving ATP levels and inhibiting oxygen consumption. Activation of this non-neuronal cardiac cholinergic system by a physiotherapeutic modality may underlie cardioprotection through the remote effect of hindlimb ischemia-reperfusion. 相似文献95.
96.
Action of xyloglucan hydrolase within the native cell wall architecture and its effect on cell wall extensibility in azuki bean epicotyls 总被引:11,自引:0,他引:11
Xyloglucan hydrolase (XGH) has recently been purified from the cell wall of azuki bean (Vigna angularis Ohwi et Ohashi) epicotyls as a new type of xyloglucan-degrading enzyme [Tabuchi et al. (2001) Plant Cell Physiol. 42: 154]. In the present study, the effects of XGH on the mechanical properties of the cell wall and on the level and the molecular size of xyloglucans within the native wall architecture were examined in azuki bean epicotyls. When the epidermal tissue strips from the growing regions of azuki bean epicotyls were incubated with XGH, the mechanical extensibility of the cell wall dramatically increased. XGH exogenously applied to cell wall materials (homogenates) or epidermal tissue strips decreased the amount of xyloglucans via the solubilization of the polysaccharides. Also, XGH substantially decreased the molecular mass of xyloglucans in both materials. These results indicate that XGH is capable of hydrolyzing xyloglucans within the native cell wall architecture and thereby increasing the cell wall extensibility in azuki bean epicotyls. 相似文献
97.
Anoxia tolerance and ethanol sensitivity of rice (Oryza sativa L.) and oat (Avena sativa L.) seedlings were evaluated to clarify their growth habit in anoxia. Anoxic stress inhibited elongation and dry weight gain
of coleoptiles of the oat and rice seedlings; however, the inhibition of the oat coleoptiles was much greater than that of
the rice coleoptiles. Anoxic stress increased endogenous ethanol concentration and alcohol dehydrogenase activity in oat and
rice coleoptiles and their increases in the rice coleoptiles were much greater than those in the oat coleoptiles. At concentrations
greater than 30 mM and 300 mM, exogenously applied ethanol inhibited the elongation and weight gain for the oat and the rice
coleoptiles, respectively, and the inhibition was increased with increasing ethanol concentrations with marked inhibition
being achieved on the oat coleoptiles. These results suggest that anoxia tolerance and induction of ethanolic fermentation
in anoxia may be greater in rice than oat, and ethanol sensitivity of rice may be lower than that of oat. 相似文献
98.
Human saliva contained 4-hydroxyphenylacetic acid (HPA) (2-10 microM) and nitrite (60-300 microM). HPA was nitrated to 4-hydroxy-3-nitrophenylacetic acid (NO2HPA) when HPA and sodium nitrite were mixed at pH 1.0. NO2HPA was also formed when saliva was incubated under acidic conditions. These results suggest that salivary HPA is nitrated to NO2HPA when saliva is swallowed into the stomach. 相似文献
99.
Regulation of angiogenesis by the aging suppressor gene klotho 总被引:5,自引:0,他引:5
Fukino K Suzuki T Saito Y Shindo T Amaki T Kurabayashi M Nagai R 《Biochemical and biophysical research communications》2002,293(1):332-337
Advanced age is a major risk factor of peripheral artery disease. We examined the effects of the aging-suppressor gene klotho on angiogenesis in response to ischemia by introducing ischemic hindlimb model in mice heterozygously deficient for the klotho gene and in wild type mice. Blood flow recovery as assessed by laser doppler perfusion imaging and angiogenesis as assessed by density of PECAM-1/CD31-positive positive capillaries were markedly impaired in mice heterozygously deficient for the klotho gene (both <0.05). Our findings show that the aging-suppressor gene klotho affects angiogenesis and the possibility that age-related impairment of angiogenesis might be regulated by the klotho gene. Our results present a new possibility of therapeutic angiogenesis for patients of advanced age. 相似文献
100.
When leaves of Vicia faba were treated with H2O2 or visiblelight in the presence of methyl viologen (MV), the orange-redcompound dopachrome was formed transiently and melanin was accumulated.With the darkening of leaves, the level of 3,4-dihydroxyphenylalanine(DOPA) decreased and then recovered to the original level uponaddition of 1 mM H2O2. However, if leaves were incubated inthe presence of 10 mM H2O2, the level of DOPA decreased againafter the increase. The time course of the changes in levelsof DOPA observed during the accumulation of melanin as a resultof illumination in the presence of MV was very similar to thatobserved after the addition of 10 mM H2O2. Illumination of leavesin the absence of MV did not result in any accumulation of melanin,but the level of DOPA changed slightly. When isolated mesophyllcells were incubated in the dark, the level of DOPA decreased.Illumination of the cells stimulated this decrease. Tropolone,an inhibitor of phenol oxidase, did not inhibit and actuallystimulated the H2O2- and light-induced oxidation of DOPA andaccumulation of melanin in leaves. Tropolone also stimulatedthe decrease in the levels of DOPA both in the dark and in thelight in isolated mesophyll cells. These data suggest that aperoxidase-H2O2 system, and not phenol oxidase, participatesin the oxidation of DOPA. When DOPA was oxidized by a basicperoxidase isolated from V.faba leaves, an intermediate, whichwas perhaps dopaquinone and which was reducible by ascorbate,was formed. Based on the data, a discussion is presented ofthe physiological significance of the oxidation of DOPA by peroxidasein vacuoles. (Received March 4, 1991; Accepted May 21, 1991) 相似文献