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881.
Lanfang Li Fang Li Feng Li Xiaohuan Mao Li Yang Hao Huang Yu Guo Linxi Chen Jian Li 《International journal of peptide research and therapeutics》2011,17(4):307-315
Apelin is the endogenous ligand of the G-protein-coupled receptor, apelin–angiotensin receptor-like 1 (APJ). Vascular smooth
muscle cells express both apelin and APJ, which are important regulatory factors in the cardiovascular system. Apelin-13 significantly
stimulated vascular smooth muscle cell proliferation. However, little is known about the precise cellular mechanisms responsible
for vascular smooth muscle cell proliferation induced by apelin-13. Here, we present novel data that indicate the key role
of NADPH oxidase 4-derived reactive oxygen species in proliferation of vascular smooth muscle cells treated with apelin-13.
Apelin-13 stimulated reactive oxygen species production in a concentration- and time-dependent manner. Furthermore, DPI impaired
apelin-13-induced reactive oxygen species generation and vascular smooth muscle cell proliferation. Apelin-13-treatment increased
the expression of NADPH oxidase 4 in a dose-dependent manner. Down-regulation of NADPH oxidase 4 using siRNA prevented apelin-13-induced
reactive oxygen species generation and vascular smooth muscle cell proliferation. An increase in reactive molecules can trigger
the activation of ERK stress-sensitive signaling pathways. Additionally, siRNA-NOX4 and DPI reversed the phosphorylation of
ERK induced by apelin-13. Apelin-13 induced vascular smooth muscle cell proliferation by NOX4-derived ROS via the ERK signaling
pathway. 相似文献
882.
883.
用RDA技术寻找肝再生相关基因的初步研究 总被引:2,自引:0,他引:2
利用表达性差异显示分析 (RDA)技术 ,研究大鼠 2 /3肝部分切除后 1h肝组织中基因的选择性表达 ,建立了大鼠 2 /3肝部分切除术后 1h再生肝组织选择性表达基因EST库。该库约含 3× 10 4 个独立克隆 ,其中 95 %以上的克隆含有插入片段 ,长度约 2 0 0~ 70 0bp不等 ,对随机挑出的 5 2个克隆的序列分析表明其中大多数基因与肝再生调控相关 (38/5 2 )。 10株未报道序列经RNA杂交证实 ,其中 6株与肝再生相关。 相似文献
884.
Sayani Dasgupta Leandro M. Castro Russell Dulman Ciyu Yang Marion Schmidt Emer S. Ferro Lloyd D. Fricker 《PloS one》2014,9(7)
The proteasome cleaves intracellular proteins into peptides. Earlier studies found that treatment of human embryonic kidney 293T (HEK293T) cells with epoxomicin (an irreversible proteasome inhibitor) generally caused a decrease in levels of intracellular peptides. However, bortezomib (an antitumor drug and proteasome inhibitor) caused an unexpected increase in the levels of most intracellular peptides in HEK293T and SH-SY5Y cells. To address this apparent paradox, quantitative peptidomics was used to study the effect of a variety of other proteasome inhibitors on peptide levels in HEK293T and SH-SY5Y cells. Inhibitors tested included carfilzomib, MG132, MG262, MLN2238, AM114, and clasto-Lactacystin β-lactone. Only MG262 caused a substantial elevation in peptide levels that was comparable to the effect of bortezomib, although carfilzomib and MLN2238 elevated the levels of some peptides. To explore off-target effects, the proteosome inhibitors were tested with various cellular peptidases. Bortezomib did not inhibit tripeptidyl peptidase 2 and only weakly inhibited cellular aminopeptidase activity, as did some of the other proteasome inhibitors. However, potent inhibitors of tripeptidyl peptidase 2 (butabindide) and cellular aminopeptidases (bestatin) did not substantially alter the peptidome, indicating that the increase in peptide levels due to proteasome inhibitors is not a result of peptidase inhibition. Although we cannot exclude other possibilities, we presume that the paradoxical increase in peptide levels upon treatment with bortezomib and other inhibitors is the result of allosteric effects of these compounds on the proteasome. Because intracellular peptides are likely to be functional, it is possible that some of the physiologic effects of bortezomib and carfilzomib arise from the perturbation of peptide levels inside the cell. 相似文献
885.
Biodiesel production from high acid value waste frying oil catalyzed by superacid heteropolyacid 总被引:2,自引:0,他引:2
Cao F Chen Y Zhai F Li J Wang J Wang X Wang S Zhu W 《Biotechnology and bioengineering》2008,101(1):93-100
Transesterification of waste cooking oil with high acid value and high water contents using heteropolyacid H3PW12O40 x 6H2O (PW12) as catalyst was investigated. The hexahydrate form of PW(12) was found to be the most promising catalyst which exhibited highest ester yield 87% for transesterification of waste cooking oil and ester yield 97% for esterification of long-chain palmitic acid, respectively. The PW12 acid catalyst shows higher activity under the optimized reaction conditions compared with conventional homogeneous catalyst sulfuric acid, and can easily be separated from the products by distillation of the excess methanol and can be reused more times. The most important feature of this catalyst is that the catalytic activity is not affected by the content of free fatty acids (FFAs) and the content of water in the waste cooking oil and the transesterification can occur at a lower temperature (65 degrees C), a lower methanol oil ratio (70:1) and be finished within a shorter time. The results illustrate that PW12 acid is an excellent water-tolerant and environmentally benign acid catalyst for production of biodiesel from waste cooking oil. 相似文献
886.
887.
培养的静止软骨细胞用ConA处理后,细胞形态从扁平形变成多角形、圆形与球形,同时可以观察到细胞周边存在大量的具有折光特点的细胞外基质。ConA能够完全抑制软骨细胞DNA的合成,LD_(50)为0.4—1.0μg/ml。ConA抑制DNA合成的作用是可逆的。20mmol/L的MeMan能够完全阻断其对软骨细胞形态和DNA合成的影响。 相似文献
888.
889.
890.
一株高含玫红品的红树林海洋紫色硫细菌分离鉴定及特性 总被引:3,自引:0,他引:3
摘要:【目的】挖掘我国海洋紫色硫细菌物种资源、深入理解紫色硫细菌在红树林生态系统中的作用。【方法】采用琼脂振荡稀释法、显微技术、紫外可见吸收光谱法、TLC、HPLC 和MS 法。【结果】从福建泉州洛阳桥红树林潮间带泥水样分离获得一株细胞内含多个硫粒的细菌菌株,光合内膜呈囊状、含细菌叶绿素a 和螺菌黄质系类胡萝卜素,结合16S rRNA 基因序列分析和系统发育分析,表明该菌株属于海洋着色菌属(Marichromatium)。该菌株细胞球杆状;最适pH 范围5.7-6.7;最适盐度范围2%-3.5%;温度范围20℃
-35℃;能耐受3.6 mmol/L 硫化物;主要积累玫红品类胡萝卜素,而不是螺菌黄质;3 种细菌叶绿素组分中,一种为BChl aP,另2 种未见报道;不需要生长因子;可光同化固定CO2、能很好利用多种有机酸盐、多价态氮化物和硫化物,尤其能利用柠檬酸、葡萄糖、蔗糖、果糖和丙醇;对氯霉素、头孢唑林、苯、对羟基联苯、恩诺沙星、啶虫脒、HgCl2
和CdCl2的IC50 值分别为70、100、20、20、3、170、5 mg /L和25 mg/L。【结论】该菌株是一株轻度耐酸、高含玫红品类胡萝卜素的紫色硫细菌,被鉴定为Marichromatium gracile 新菌株,编号YL28。该菌株具有广泛利用多种碳源、氮源和硫源物质的能力,对抗生素氯霉素和头孢唑啉、农药啶虫脒、重金属汞和镉具有较强耐受性,对抗生素恩诺沙星较敏感。 相似文献