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51.
The photosynthetic characteristics of photoautotrophically culturedcells of tobacco (Nicotiana tabacum cv. Samsun NN) as well asthose of photomixotrophically cultured cells and green leaveswere investigated. Analyses revealed that on a fresh weightbasis cultured tobacco cells had lower chlorophyll contentsthan cells of green leaves. The chlorophyll content per chloro-plast,however, was almost the same in both types of cell, and thechloroplast number per cell accounted for only small differencesin the cellular chlorophyll content. This indicates that thelarger cell volume of cultured cells is the main factor in thedifference in the chlorophyll content of these cells. Photosynthetic activity measurements also showed differencesin the chloroplasts of cultured and leaf cells. The maximumactivities of photosystem I and the Hill reaction for the culturedcells were about half those for leaf cells on a per unit chlorophyllbasis. Moreover, photo-autotrophic cells had relatively constantphotosystem I and Hill reaction activities during growth; whereas,on a fresh weight basis these activities in leaf cells reflecteddevelopmental changes in the chlorophyll content. Lithium dodecyl sulfate-polyacrylamide gel electrophoresis showedqualitatively similar thylakoid polypeptide compositions forcultured and leaf cells at all stages of growth even thoughthere were quantitative decreases in the contents of severalpolypeptides in the cultured green cells (especially in photomixotrophiccells) in comparison to the polypeptide contents of tobaccoleaves. We speculate that the lower photosynthetic activityof the cultured cells may be caused by this reduction in thecontents of certain thylakoid polypeptides. (Received November 14, 1988; Accepted June 19, 1989) 相似文献
52.
Naoki Shibata Hiroko Tamagaki Naoki Hieda Keita Akita Hirofumi Komori Yasuhito Shomura Shin-ichi Terawaki Koichi Mori Noritake Yasuoka Yoshiki Higuchi Tetsuo Toraya 《The Journal of biological chemistry》2010,285(34):26484-26493
N-terminal truncation of the Escherichia coli ethanolamine ammonia-lyase β-subunit does not affect the catalytic properties of the enzyme (Akita, K., Hieda, N., Baba, N., Kawaguchi, S., Sakamoto, H., Nakanishi, Y., Yamanishi, M., Mori, K., and Toraya, T. (2010) J. Biochem. 147, 83–93). The binary complex of the truncated enzyme with cyanocobalamin and the ternary complex with cyanocobalamin or adeninylpentylcobalamin and substrates were crystallized, and their x-ray structures were analyzed. The enzyme exists as a trimer of the (αβ)2 dimer. The active site is in the (β/α)8 barrel of the α-subunit; the β-subunit covers the lower part of the cobalamin that is bound in the interface of the α- and β-subunits. The structure complexed with adeninylpentylcobalamin revealed the presence of an adenine ring-binding pocket in the enzyme that accommodates the adenine moiety through a hydrogen bond network. The substrate is bound by six hydrogen bonds with active-site residues. Argα160 contributes to substrate binding most likely by hydrogen bonding with the O1 atom. The modeling study implies that marked angular strains and tensile forces induced by tight enzyme-coenzyme interactions are responsible for breaking the coenzyme Co–C bond. The coenzyme adenosyl radical in the productive conformation was modeled by superimposing its adenine ring on the adenine ring-binding site followed by ribosyl rotation around the N-glycosidic bond. A major structural change upon substrate binding was not observed with this particular enzyme. Gluα287, one of the substrate-binding residues, has a direct contact with the ribose group of the modeled adenosylcobalamin, which may contribute to the substrate-induced additional labilization of the Co–C bond. 相似文献
53.
Natalia J. Martinez Ganesha Rai Adam Yasgar Wendy A. Lea Hongmao Sun Yuhong Wang Diane K. Luci Shyh-Ming Yang Kana Nishihara Shunichi Takeda Mohiuddin Irina Earnshaw Tetsuya Okada Kazutoshi Mori Kelli Wilson Gregory J. Riggins Menghang Xia Maurizio Grimaldi Ajit Jadhav David J. Maloney Anton Simeonov 《PloS one》2016,11(11)
54.
Koichi Shibasaki Masatoshi Kimura Ryuichi Ikarashi Akira Yamaguchi Takuya Watanabe 《Metabolomics : Official journal of the Metabolomic Society》2012,8(3):484-491
To date, few studies have examined uric acid in saliva or dental calculus. The purpose of this study is to examine the uric acid concentration in saliva and serum. Saliva and blood samples were collected from 244 participants. We divided them into four groups: untreated or treated group in normal or abnormal serum uric acid concentration groups. Within the untreated group, Pearson??s correlation coefficient was used to examine the correlation between salivary and serum uric acid concentrations. We compared uric acid concentrations between saliva and serum, or between untreated and treated groups using the paired or unpaired student??s t-test. In the untreated group, uric acid concentrations in saliva and serum were significantly and positively correlated (r?=?0.503, P?<?0.01). Within the untreated group, those with abnormal serum uric acid concentrations had significantly higher uric acid concentrations in serum and saliva compared to those with normal serum uric acid concentrations (P?<?0.01). Within the untreated group, uric acid concentrations in serum were significantly higher than that in saliva (P?<?0.01). Uric acid concentrations in saliva of the treated group were significantly higher than that of the untreated group (P?<?0.01). Within the treated group, uric acid concentrations in saliva were significantly higher than that of serum, particularly in users of benzbromarone (P?<?0.01). Uric acid concentrations in saliva were lower than that in serum among non-users of benzbromarone. In contrast, uric acid concentrations in saliva of patients taking benzbromarone were higher than that in serum. We surmise that URAT1 may influence uric acid excretion in the salivary gland. 相似文献
55.
Sesquiterpenoids from Ferula kuhistanica 总被引:1,自引:0,他引:1
Chen B Teranishi R Kawazoe K Takaishi Y Honda G Itoh M Takeda Y Kodzhimatov OK 《Phytochemistry》2000,54(7):717-722
Methanol extracts of the air-dried roots and stems of Ferula kuhistanica afforded seven daucane-type sesquiterpenes, called kuhistanicaol A-G, together with 13 known daucane esters. Their structures were established on the basis of spectroscopic evidence and the results of chemical reactions. 相似文献
56.
There are synaptic vesicles that are labeled by Timm's sulfide-silver staining method in the brain, suggesting that synaptic vesicles contain metals such as zinc and copper. Zinc is co-released with glutamate and the importance of zinc signaling in the intracellular compartment, in addition to extracellular compartment, is becoming recognized. Zinc can pass through calcium channels, while blocking them. Calcium signaling plays a critical role for synaptic activity and crosstalk between zinc signaling with calcium signaling through calcium channels may participate in synaptic neurotransmission including synaptic plasticity such as long-term potentiation. Copper released into the synaptic cleft during synaptic excitation may also participate in synaptic neurotransmission. Other metals including copper potentially serve as calcium channel blockers and also influence calcium signaling and zinc signaling via the interaction with metal-binding proteins such as metallothioneins. Homeostasis of metals needs to be controlled spatiotemporally for proper brain function, and their dyshomeostasis is associated with neurological diseases. However, the data on the dynamic action of metals at synapses is limited and their significance poorly understood. This paper summarizes the action of metals in synaptic neurotransmission focused on calcium signaling at glutamatergic synapses. 相似文献
57.
58.
Umezawa M Sakata C Tanaka N Kudo S Tabata M Takeda K Ihara T Sugamata M 《Cytokine》2008,43(2):105-109
The pathogenesis of endometriosis, a gynecologic disorder associated with infertility, appears to involve immune responses. However, the details involved have not been clarified. In this study, we analyzed expression levels of interleukin (IL)-6, IL-10, monocyte chemoattractant protein-1, eosinophil chemotactic protein, macrophage inflammatory protein-1α, and regulated on activation normal T cell expressed and secreted (RANTES) and CC chemokine receptor 1 in endometriotic lesions in a rat model in which endometrium is autotransplanted onto peritoneal tissue and found that they were remarkably increased, while those of IL-2, IL-4, and interferon-γ were not. These results were obtained in a rat model induced by autologous, not allogeneic, transplantation of endometrial epithelium to the peritoneum. Expression of these factors is consistent with that of endometriosis in humans. Therefore, this model may be useful in the investigation of the pathogenesis and treatment of endometriosis. 相似文献
59.
The karyotype and other chromosomal markers as revealed by C-banding and Ag-staining were studied in Lutjanus quinquelineatus and L. kasmira (Lutjanidae, Perciformes). While in latter species, the karyotype was invariably composed of 48 acrocentric chromosomes in
both sexes, in L. quinquelineatus the female karyotype had exclusively 48 acrocentric chromosomes (2n = 48) but that of the male consisted of one large metacentric and 46 acrocentric chromosomes (2n = 47). The chromosomes in the first meiotic division in males showed 22 bivalents and one trivalent, which was formed by
an end-to-end association and a chiasmatic association. Multiple sex chromosome system of X1X1X2X2/X1X2Y type resulting from single Robertsonian fusion between the original Y chromosome and an autosome was hypothesized to produce
neo-Y sex chromosome. The multiple sex chromosome system of L. quinquelineatus appears to be at the early stage of the differentiation. The positive C-banded heterochromatin was situated exclusively in
centromeric regions of all chromosomes in both species. Similarly, nucleolus organizer region sites were identified in the
pericentromeric region of one middle-sized pair of chromosomes in both species. The cellular DNA contents were the same (3.3 pg)
between the sexes and among this species and related species. 相似文献
60.
Endothelial NO Synthase (eNOS) phosphorylation regulates coronary diameter during ischemia-reperfusion in association with oxidative stress 总被引:3,自引:0,他引:3
Hoshino S Kikuchi Y Nakajima M Kimura H Tsuyama S Uemura K Yoshida K 《Free radical research》2005,39(5):481-489
The link between endothelial nitric oxide synthase (eNOS) activation and vascular diameter during ischemia-reperfusion was investigated in the rat heart. After short (<30 min) and long (>45 min) time of ischemia conferred by coronary artery occlusion of the rats, reperfusion caused dilatation and constriction of arterioles, respectively. Partial oxygen pressure (pO2) measurement of the heart by the electrode confirmed the hyper-perfusion and no-reflow phenomena during reperfusion, as well as myocardial ischemia. The vascular diameter was correlated with phosphorylation of Akt and serine 1177 residue of eNOS, and formation of NO-bound guanylate cyclase (GC) by immuoflorescence study. Western blotting confirmed the phosphorylation of eNOS-Ser1177 depending on ischemia time. The constriction during reperfusion after 45 min of ischemia is supposedly caused by the inhibition of Akt-mediated eNOS-Ser1177 phosphorylation, which was suppressed by a PKC inhibitor chelerythrine, or ROS scavengers N-2-mercaptopropionyl glycine (MPG) and 4,5-Dihydroxy-1, 3-benzenedisulfonic acid disodium salt (Tiron). However, an endothelin receptor antagonist BQ123 alleviated the vasoconstriction by increasing NO availability but not eNOS-Ser1177 phosphorylation. Thus, vascular patency is correlated with eNOS-Ser1177 phosphorylation in association with ROS, and PKC during reperfusion. Endothelin inhibits vasodilatation by reducing NO availability during reperfusion. 相似文献