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991.
Targeting of mitochondria by 10-N-alkyl acridine orange analogues: role of alkyl chain length in determining cellular uptake and localization 总被引:1,自引:0,他引:1
Rodriguez ME Azizuddin K Zhang P Chiu SM Lam M Kenney ME Burda C Oleinick NL 《Mitochondrion》2008,8(3):237-246
10-N-Nonyl acridine orange (NAO) is used as a mitochondrial probe because of its high affinity for cardiolipin (CL). Targeting of NAO may also depend on mitochondrial membrane potential. As the nonyl group has been considered essential for targeting, a systematic study of alkyl chain length was undertaken; three analogues (10-methyl-, 10-hexyl-, and 10-hexadecyl-acridine orange) were synthesized and their properties studied in phospholipid monolayers and breast cancer cells. The shortest and longest alkyl chains reduced targeting, whereas the hexyl group was superior to the nonyl group, allowing very clear and specific targeting to mitochondria at concentrations of 20-100 nM, where no evidence of toxicity was apparent. Additional studies in wild-type and cardiolipin-deficient yeast cells suggested that cellular binding was not absolutely dependent upon cardiolipin. 相似文献
992.
993.
Chiu JH Peng YN Yang YL Tsai MH Ho YL Wu CY Liu MY 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2008,875(2):383-391
A simple capillary zone electrophoresis (CZE) method was used to determine native, in vitro Cu(2+) and glucose modified low-density lipoprotein (LDL) particles for four healthy subjects. The LDL electropherograms are highly reproducible with good precisions of effective mobility and peak area. The native LDL capillary electrophoresis (CE) profile shows a major peak with lower mobility and two minor peaks with higher mobilities. For three-hour Cu(2+) oxidation, one major peak with mobility close to that of the native major peak, and one minor peak with mobility extending to -47 x 10(-5)cm(2)V(-1)s(-1) appear. For eighteen-hour Cu(2+) oxidation, one major peak with mobility much higher than that of the native major peak appears. As the reaction time for LDL and Cu(2+) increases from 0 to 24h, effective mobility of the LDL major peak increases, suggesting that LDL particles become more negatively charged and oxidized as the time increases. The in vitro glycated LDL particles are characterized by a major peak and two minor peaks. Mobility of the major peak is close to that of native major peak, but the second minor peak is much more negatively charged with mobility extending to -53 x 10(-5)cm(2)V(-1)s(-1). Native, oxidized and glycated LDL particles show distinctive differences in their CZE profiles. Agarose electrophoresis shows that the charge to mass ratios of native, three-hour Cu(2+) and glucose modified LDL particles are similar, but that of eighteen-hour Cu(2+) oxidized LDL particles is higher. 相似文献
994.
Chromium (Cr) has been widely used in industry for more than one century. Exposure to hexavalent Cr compounds is strongly associated with increasing risk of lung cancer. Extensive researches at DNA level indicated that generation of ROS from the reduction of Cr(VI) leading to DNA damage is the major cause of the toxicity and carcinogenicity of Cr(VI). The present study in cellular and protein levels confirmed that Cr(VI) induced apoptosis of lung epithelial cells (LEC) via ROS generation. To view the differentially expressed proteins in the process of Cr(VI) reduction, subcellular proteomics was applied and allowed the identification of more than 30 proteins with expression alteration. Most of those proteins are correlated with ROS-elicited responses, which were further validated by Western blotting analysis, induction of p53 pathway and antioxidative treatment. The current findings provided additional evidence in protein level to support the claim that ROS generated during the process of Cr(VI) reduction are involved in the Cr(VI)-induced toxicity and carcinogenesis. 相似文献
995.
Shih-Chang Chien Cheng-Chi Chen Hsi-Lin Chiu Chi-I Chang Mei-Hwei Tseng Yueh-Hsiung Kuo 《Phytochemistry》2008,69(12):2336-2340
Seven nor- and podocarpane-type diterpenes were isolated from the bark of Taiwania cryptomerioides Hayata, including three 18-nor-podocarpanes: 18-nor-1beta,4alpha,14-trihydroxy-13-methoxy-8,11,13-podocarpatriene (1), 18-nor-1beta,4alpha,13,14-tetrahydroxy-8,11,13-podocarpatrien-7-one (2), 18-nor-1beta,4alpha,14-trihydroxy-13-methoxy-8,11,13-podocarpatrien-7-one (3), 1beta,14,19-trihydroxy-13-methoxy-8,11,13-podocarpatrien-7-one (4), 1beta,13,14,18-tetrahydroxy-8,11,13-podocarpatrien-7-one (5), 18-acetoxy-1beta,13,14-trihydroxy-8,11,13-podocarpatrien-7-one (6), and 1beta,14,18-trihydroxy-13-methoxy-8,11,13-podocarpatrien-7-one (7). Their structures were determined by application of 1D and 2D NMR spectroscopy and other techniques. Podocarpane-type diterpenes do not occur extensively in nature, and the presumed oxidative enzyme in this plant will be of interest to identify. 相似文献
996.
The ParB family partitioning protein, KorB, of plasmid RK2 is central to a regulatory network coordinating replication, maintenance and transfer genes. Previous immunofluorescence microscopy indicated that the majority of KorB is localized in plasmid foci. The 12 identified KorB binding sites on RK2 are differentiated by: position relative to promoters; binding strength; and cooperativity with other repressors and so the distribution of KorB may be sequestered around a sub-set of sites. However, chromatin immunoprecipitation analysis showed that while RK2 DNA molecules appear to sequester KorB to create a higher local concentration, cooperativity between DNA binding proteins does not result in major differences in binding site occupancy. Thus under steady state conditions all operators are close to fully occupied and this correlates with gene expression on the plasmid being highly repressed. 相似文献
997.
Arsenite activation of P13K/AKT cell survival pathway is mediated by p38 in cultured human keratinocytes. 总被引:6,自引:0,他引:6
K Souza D A Maddock Q Zhang J Chen C Chiu S Mehta Y Wan 《Molecular medicine (Cambridge, Mass.)》2001,7(11):767-772
BACKGROUND: Arsenic has been considered as a carcinogen. Recently the issue of arsenic in drinking water raised an unprecedented social concern on human health, and yet the molecular mechanisms through which arsenic induces cancer remain unknown. Activation of cell survival pathway leading to the activation of eNOS has been associated with various types of cancer. The objective of this study was to investigate the pathway leading to the activation of eNOS in response to arsenite using human keratinocytes. MATERIALS AND METHODS: Cultured keratinocytes (HaCat cells) were exposed to arsenite with or without pretreatment of various inhibitors. Western blot analysis was performed to determine the activation of p38, AKT, eNOS. EGFR tyrosine phosphorylation was detected by immunoprecipitation and Western blot analysis. pNPP assay was used to measure phosphatase activity in cell lysate. FACS analysis was performed for the determination of generation of reactive oxygen species. RESULTS: Arsenite induced the activation of AKT at both Ser473 and Thr308, and its downstream effector eNOS in cultured human keratinocytes. Arsenite also induced phosphorylation of p38. PI-3-kinase inhibitors, Wortmannin and LY294002 inhibited arsenite-induced phosphorylation of AKT and eNOS but had no effect on phosphorylation of p38. Interestingly, however, SB203580, a known p38 inhibitor, completely inhibited arsenite-induced phosphorylation of AKT and eNOS. Arsenite induced generation of reactive oxygen species and inactivated phosphatase activity, but did not activate EGF receptor tyrosine phosphorylation. CONCLUSIONS: Collectively, our data indicate that arsenite induces activation of AKT and eNOS, via PI-3-kinase and p38 pathway, likely bypassing the activation of EGF receptor in cultured human keratinocytes. 相似文献
998.
Wang Jyh-Shyang Chiu Kuo-Pin Lin Chien-Yon Tsai Yu-Hsuan Yuan Chi-Tsu 《Plasmonics (Norwell, Mass.)》2017,12(2):433-438
Plasmonics - The spontaneous emission of a light source can be modified by tailoring its local density of optical states. Indeed, this concept has been commonly utilized to enhance the spontaneous... 相似文献
999.
Using Ultralow Dosages of Electron Acceptor to Reveal the Early Stage Donor–Acceptor Electronic Interactions in Bulk Heterojunction Blends 下载免费PDF全文
Carr Hoi Yi Ho Sin Hang Cheung Ho‐Wa Li Ka Lok Chiu Yuanhang Cheng Hang Yin Mau Hing Chan Franky So Sai‐Wing Tsang Shu Kong So 《Liver Transplantation》2017,7(12)
Tuning the donor–acceptor (D–A) weight ratio is an essential step to optimize the performance of a bulk heterojunction (BHJ) solar cell. The unoptimized regime with a low acceptor concentration is generally unexplored despite it may reveal the early stage electronic D–A interactions. In this study, PTB7:PC71BM is used to examine factors that limit the device performance in unoptimized regime. The key limiting factor is the creation of traps and localized states originated from fullerene molecules. Photothermal deflection spectroscopy is used to quantify the trap density. Starting with pristine PTB7, addition of small concentration of fullerene increases the electron trap density and lowers the electron mobility. When the D–A weight ratio reaches 1:0.1, fullerene percolation occurs. There is an abrupt drop in trap density and simultaneously a six orders of magnitude increase in the electron mobility. Furthermore, the fill factors of the corresponding photovoltaic devices are found to anticorrelate with the trap density. This study reveals that electron trapping is the key limiting factor for unoptimized BHJ solar cells in low fullerene regime. 相似文献
1000.
Ya-Ni Huang Ling-Yu Yang Jing-Ya Wang Chien-Cheng Lai Chien-Tsai Chiu Jia-Yi Wang 《Molecular neurobiology》2017,54(1):125-136
Methamphetamine (METH)-induced cell death contributes to the pathogenesis of neurotoxicity; however, the relative roles of oxidative stress, apoptosis, and autophagy remain unclear. L-Ascorbate, also called vitamin (Vit.) C, confers partial protection against METH neurotoxicity via induction of heme oxygenase-1. We further investigated the role of Vit. C in METH-induced oxidative stress, apoptosis, and autophagy in cortical cells. Exposure to lower concentrations (0.1, 0.5, 1 mM) of METH had insignificant effects on ROS production, whereas cells exposed to 5 mM METH exhibited ROS production in a time-dependent manner. We confirmed METH-induced apoptosis (by nuclear morphology revealed by Hoechst 33258 staining and Western blot showing the protein levels of pro-caspase 3 and cleaved caspase 3) and autophagy (by Western blot showing the protein levels of Belin-1 and conversion of microtubule-associated light chain (LC)3-I to LC3-II and autophagosome staining by monodansylcadaverine). The apoptosis as revealed by cleaved caspase-3 expression marked an increase at 18 h after METH exposure while both autophagic markers, Beclin 1 and LC3-II, marked an increase in cells exposed to METH for 6 and 24 h, respectively. Treating cells with Vit. C 30 min before METH exposure time-dependently attenuated the production of ROS. Vitamin C also attenuated METH-induced Beclin 1 and LC3-II expression and METH toxicity. Treatment of cells with Vit. C before METH exposure attenuated the expression of cleaved caspase-3 and reduced the number of METH-induced apoptotic cells. We suggest that the protective effect of Vit. C against METH toxicity might be through attenuation of ROS production, autophagy, and apoptosis. 相似文献