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991.
Living in an enriched environment with complex physical and social stimulation leads to improved cognitive and metabolic health. In white fat, enrichment induced the upregulation of the brown fat cell fate determining gene Prdm16, brown fat-specific markers, and genes involved in thermogenesis and β-adrenergic signaling. Moreover, pockets of cells with prototypical brown fat morphology and high UCP1 levels were observed in the white fat of enriched mice associated with resistance to diet-induced obesity. Hypothalamic overexpression of BDNF reproduced the enrichment-associated activation of the brown fat gene program and lean phenotype. Inhibition of BDNF signaling by genetic knockout or dominant-negative trkB reversed this phenotype. Our genetic and pharmacologic data suggest a mechanism whereby induction of hypothalamic BDNF expression in response to environmental stimuli leads to selective sympathoneural modulation of white fat to induce "browning" and increased energy dissipation. 相似文献
992.
Junjie Xiao Huaming Cao Dandan Liang Ying Liu Hong Zhang Hong Zhao Yi Liu Jun Li Biao Yan Luying Peng Zhaonian Zhou Yi‐Han Chen 《Journal of cellular and molecular medicine》2011,15(5):1166-1176
Microtubule integrity is important in cardio‐protection, and microtubule disruption has been implicated in the response to ischemia in cardiac myocytes. However, the effects of Taxol, a common microtubule stabilizer, are still unknown in ischemic ventricular arrhythmias. The arrhythmia model was established in isolated rat hearts by regional ischemia, and myocardial infarction model by ischemia/reperfusion. Microtubule structure was immunohistochemically measured. The potential mechanisms were studied by measuring reactive oxygen species (ROS), activities of oxidative enzymes, intracellular calcium concentration ([Ca2+]i) and Ca2+ transients by using fluorometric determination, spectrophotometric assays and Fura‐2‐AM and Fluo‐3‐AM, respectively. The expression and activity of sarcoplasmic reticulum Ca2+‐ATPase (SERCA2a) was also examined using real‐time polymerase chain reaction, Western blot and pyruvate/Nicotinamide adenine dinucleotide‐coupled reaction. Our data showed that Taxol (0.1, 0.3 and 1 μM) effectively reduced the number of ventricular premature beats and the incidence and duration of ventricular tachycardia. The infarct size was also significantly reduced by Taxol (1 μM). At the same time, Taxol preserved the microtubule structure, increased the activity of mitochondrial electron transport chain complexes I and III, reduced ROS levels, decreased the rise in [Ca2+]i and preserved the amplitude and decay times of Ca2+ transients during ischemia. In addition, SERCA2a activity was preserved by Taxol during ischemia. In summary, Taxol prevents ischemic ventricular arrhythmias likely through ameliorating abnormal calcium homeostasis and decreasing the level of ROS. This study presents evidence that Taxol may be a potential novel therapy for ischemic ventricular arrhythmias. 相似文献
993.
Yanyi Liu Michael Clark Qifeng Zhang Danmei Yu Dawei Liu Jun Liu Guozhong Cao 《Liver Transplantation》2011,1(2):194-202
Nanostructured V2O5 thin films have been prepared by means of cathodic deposition from an aqueous solution made from V2O5 and H2O2 directly on fluorine‐doped tin oxide coated (FTO) glasses followed by annealing at 500°C in air, and studied as film electrodes for lithium ion batteries. XPS results show that the as‐deposited films contained 15% V4+, however after annealing all the vanadium is oxidized to V5+. The crystallinity, surface morphology, and microstructures of the films have been investigated by means of XRD, SEM, and AFM. The V2O5 thin film electrodes show excellent electrochemical properties as cathodes for lithium ion intercalation: a high initial discharge capacity of 402 mA h g?1 and 240 mA h g?1 is retained after over 200 cycles with a discharging rate of 200 mA g?1 (1.3 C). The specific energy density is calculated as 900 W h kg?1 for the 1st cycle and 723 W h kg?1 for the 180th cycle when the films are tested at 200 mA g?1 (1.3 C). When discharge/charge is carried out at a high current density of 10.5 A g?1 (70 C), the thin film electrodes retain a good discharge capacity of 120 mA h g?1, and the specific power density is over 28 kW kg?1. 相似文献
994.
Li Y Zheng H Luo R Wu H Zhu H Li R Cao H Wu B Huang S Shao H Ma H Zhang F Feng S Zhang W Du H Tian G Li J Zhang X Li S Bolund L Kristiansen K de Smith AJ Blakemore AI Coin LJ Yang H Wang J Wang J 《Nature biotechnology》2011,29(8):723-730
Here we use whole-genome de novo assembly of second-generation sequencing reads to map structural variation (SV) in an Asian genome and an African genome. Our approach identifies small- and intermediate-size homozygous variants (1-50 kb) including insertions, deletions, inversions and their precise breakpoints, and in contrast to other methods, can resolve complex rearrangements. In total, we identified 277,243 SVs ranging in length from 1-23 kb. Validation using computational and experimental methods suggests that we achieve overall <6% false-positive rate and <10% false-negative rate in genomic regions that can be assembled, which outperforms other methods. Analysis of the SVs in the genomes of 106 individuals sequenced as part of the 1000 Genomes Project suggests that SVs account for a greater fraction of the diversity between individuals than do single-nucleotide polymorphisms (SNPs). These findings demonstrate that whole-genome de novo assembly is a feasible approach to deriving more comprehensive maps of genetic variation. 相似文献
995.
To investigate the expression and biological significance of Leptin, Leptin receptor, Vascular Endothelial Growth Factor (VEGF),
and CD34 protein in colorectal carcinoma tissues. The expression of Leptin, Leptin receptor, VEGF, and CD34 was detected in
68 cases of colorectal carcinoma tissues, paired para-carcinoma tissues and normal colorectal tissues by Immunohistochemical
SP Method. The results and related clinicopathological data were analyzed. The positive rate of Leptin, Leptin receptor, and
VEGF was significantly higher in colorectal carcinoma tissues than that in paired para-carcinoma tissues and normal colorectal
tissues. The expression of Leptin, Leptin receptor, and VEGF was correlated with grade of tumor differentiation, depth of
bowel wall invasion, lymph node metastasis, Dukes stage, distant metastasis, and lympho/vascular tumor embolization. Microvessel
density (MVD) value in colorectal carcinoma was significantly higher than that in para-carcinoma tissues and normal colorectal
tissues, and the density in para-carcinoma tissues was higher than that in normal colorectal tissues. The expression of Leptin,
Leptin receptor, VEGF, and MVD value in colorectal carcinoma was positively correlated. In conclusion, microvessel density
value is an important index of the growth, invasion, and metastasis of colorectal carcinoma. The binding of Leptin and Leptin
receptor promotes the proliferation of colorectal carcinoma cells. The synergy between Leptin and VEGF accelerates the angiogenesis
in colorectal carcinoma and accelerates the invasion and metastasis of the tumor cells. 相似文献
996.
Choksi S Lin Y Pobezinskaya Y Chen L Park C Morgan M Li T Jitkaew S Cao X Kim YS Kim HS Levitt P Shih G Birre M Deng CX Liu ZG 《Molecular cell》2011,42(5):597-609
The regulation of apoptosis is critical for controlling tissue homeostasis and preventing tumor formation and growth. Reactive oxygen species (ROS) generation plays a key role in such regulation. Here, we describe a HIF-1 target, Vasn/ATIA (anti-TNFα-induced apoptosis), which protects cells against TNFα- and hypoxia-induced apoptosis. Through the generation of ATIA knockout mice, we show that ATIA protects cells from apoptosis through regulating the function of the mitochondrial antioxidant, thioredoxin-2, and ROS generation. ATIA is highly expressed in human glioblastoma, and ATIA knockdown in glioblastoma cells renders them sensitive to hypoxia-induced apoptosis. Therefore, ATIA is not only a HIF-1 target that regulates mitochondrial redox pathways but also a potentially diagnostic marker and therapeutic target in human glioblastoma. 相似文献
997.
Yabin Wang Kazim Narsinh Li Zhao Dongdong Sun Dongjuan Wang Zheng Zhang Zhongchan Sun Rongqing Zhang Haichang Wang Feng Cao 《Cell biology international》2011,35(2):135-140
Ghrelin is thought to directly exert a protective effect on the cardiovascular system, specifically by promoting vascular endothelial cell function. Our study demonstrates the ability of ghrelin to promote rat CMEC (cardiac microvascular endothelial cell) proliferation, migration and NO (nitric oxide) secretion. CMECs were isolated from left ventricle of adult male Sprague—Dawley rat by enzyme digestion and maintained in endothelial cell medium. Dil‐ac‐LDL (1,1′‐dioctadecyl‐3,3,3′,3′‐ tetramethylindocarbocyanine‐labelled acetylated low‐density lipoprotein) intake assays were used to identify CMECs. Cells were split into five groups and treated with varying concentrations of ghrelin as follows: one control non‐treated group; three ghrelin dosage groups (1×10?9, 1×10?8, 1×10?7 mol/l) and one ghrelin+PI3K inhibitor group (1×10?7 mol/l ghrelin+20 μmol/l LY294002). After 24 h treatment, cell proliferation capability was measured by MTT [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide] assay and Western blot for PCNA (proliferating cell nuclear antigen) protein expression. Migration of CMECs was detected by transwell assays, and NO secretion of CMECs was measured via nitrate reduction. Protein expression of AKT and phosphorylated AKT in CMECs was measured by Western blot after exposure to various concentrations of ghrelin and the PI3K inhibitor LY294002. Our results indicate that ghrelin significantly enhanced cell growth at concentrations of 10?8 mol/l (0.271±0.041 compared with 0.199±0.021, P=0.03) and 10?7 mol/l (0.296±0.039 compared with 0.199±0.021, P<0.01). However, addition of the PI3K/AKT inhibitor LY294002 inhibited the ghrelin‐mediated enhancement in cell proliferation (0.227±0.042 compared with 0.199±0.021, P=0.15). At a concentration between 10?8 and 10?7 mol/l, ghrelin caused a significant increase in the number of migrated cells compared with the control group (126±9 compared with 98±7, P=0.02; 142±6 compared with 98±7, P<0.01), whereas no such change could be observed in the presence of 20 μmol/l of the PI3K/Akt inhibitor LY294002 (103±7 compared with 98±7, P=0.32). Ghrelin treatment significantly enhanced NO production in a dose‐dependent fashion compared with the untreated control group [(39.93±2.12) μmol/l compared with (30.27±2.71) μmol/l, P=0.02; (56.80±1.98) μmol/l compared with (30.27±2.71) μmol/l, P<0.01]. However, pretreatment with 20 μmol/l LY294002 inhibited the ghrelin‐stimulated increase in NO secretion [(28.97±1.64) μmol/l compared with (30.27±2.71) μmol/l, P=0.37]. In summary, we have found that ghrelin treatment promotes the proliferation, migration and NO secretion of CMECs through activation of PI3K/AKT signalling pathway. 相似文献
998.
999.
Youshuang Zhu Haibo Zhang Mingle Cao Zhenzhen Wei Feng Huang Peiji Gao 《Biotechnology and Bioprocess Engineering》2011,16(5):1027-1035
Production of laccase using a submerged culture of Trametes versicolor sdu-4 was optimized using a central composite design of the Response Surface Methodology. Optimized conditions gave a laccase
yield of 4,213 U/L which was approximately three times of that in basal medium. The laccase was purified to homogeneity using
a three-step process. The overall yield of the purification was 58%, with a purification fold of 11.4 and a specific activity
of 1320.7 U/mg protein. The molecular mass of the laccase was 60 kDa. The optimum pH values of the enzyme were 2.2, 3.7, and
7 for the oxidations of ABTS, DMP, and syringaldazine, respectively. The enzyme had adaptability to a broad pH range and high
temperature and wsa stable at pH 3.0 ∼ 10.0. The half-life of this laccase at 70°C was 2.2 h. Methyl red, 2-bromophenol, and
4-bromophenol were oxidized by the purified laccase in the absence of mediators. Purified laccase was effective in the decolorization
of several dyes and was not inhibited by Cu2+, Mn2+, Zn2+, Na+, K+, Mg2+, Ba2+, and Ca2+ at 5 mM. These excellent characteristics made it a highly attractive candidate for industrial use. 相似文献
1000.
Cao Y Evans SC Soans E Malki A Liu Y Liu Y Chen X 《Apoptosis : an international journal on programmed cell death》2011,16(9):902-913
p53 is essential for cell cycle arrest and apoptosis induction while insulin receptor (IR) signaling is important for cell
metabolism and proliferation and found upregulated in cancers. While IR has recently been found to be involved in apoptosis,
p53 induction or apoptosis mediated through IR signaling activation has never been documented. Here, we report that the IR
signaling pathway, particularly the IR-MEK pathway, mediates biological and biochemical changes in p53 and apoptosis in tumor
cells. Specifically, natural compound penta-O-galloyl-α-d-glucopyranose (α-PGG), a previously characterized IR signaling activator, induced apoptosis in RKO cells without significantly
affecting its normal counterpart FHC cells. α-PGG induced apoptosis in RKO cells through p53, Bax and caspase 3. Importantly,
α-PGG’s ability to elevate p53 was diminished by IR inhibitor and IR-siRNA, suggesting a non-conventional role of IR as being
involved in p53 induction. Further studies revealed that α-PGG activated MEK, a downstream signaling factor of IR. Blocking
MEK significantly suppressed α-PGG-induced p53 and Bax elevation. All these results suggested that α-PGG induced p53, Bax,
and apoptosis through the IR-MEK signaling pathway. The unique activity of α-PGG, a novel IR phosphorylation and apoptosis
inducer, may offer a new therapeutic strategy for eliciting apoptotic signal and inhibiting cancer growth. 相似文献