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991.
Weidong Li Qian Wang Qiaozhen Su Dandan Ma Chang An Lei Ma Hongfeng Liang 《Molecules and cells》2014,37(5):383-388
Renal cell carcinoma (RCC) is associated with a high frequency of metastasis and only few therapies substantially prolong survival. Honokiol, isolated from Magnolia spp. bark, has been shown to exhibit pleiotropic anticancer effects in many cancer types. However, whether honokiol could suppress RCC metastasis has not been fully elucidated. In the present study, we found that honokiol suppressed renal cancer cells’ metastasis via dual-blocking epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) properties. In addition, honokiol inhibited tumor growth in vivo. It was found that honokiol could up-regulate miR-141, which targeted ZEB2 and modulated ZEB2 expression. Honokiol reversed EMT and suppressed CSC properties partly through the miR-141/ZEB2 axis. Our study suggested that honokiol may be a suitable therapeutic strategy for RCC treatment. 相似文献
992.
Hae Jin Jeong Sung Yeon Lee Nam Seon Kang Yeong Du Yoo An Suk Lim Moo Joon Lee Hyung Seop Kim Wonho Yih Hiroshi Yamashita Todd C. LaJeunesse 《The Journal of eukaryotic microbiology》2014,61(1):75-94
Dinoflagellates in the genus Symbiodinium are ubiquitous in shallow marine habitats where they commonly exist in symbiosis with cnidarians. Attempts to culture them often retrieve isolates that may not be symbiotic, but instead exist as free‐living species. In particular, cultures of Symbiodinium clade E obtained from temperate environments were recently shown to feed phagotrophically on bacteria and microalgae. Genetic, behavioral, and morphological evidence indicate that strains of clade E obtained from the northwestern, southwestern, and northeastern temperate Pacific Ocean as well as the Mediterranean Sea constitute a single species: Symbiodinium voratum n. sp. Chloroplast ribosomal 23S and mitochondrial cytochrome b nucleotide sequences were the same for all isolates. The D1/D2 domains of nuclear ribosomal DNA were identical among Western Pacific strains, but single nucleotide substitutions differentiated isolates from California (USA) and Spain. Phylogenetic analyses demonstrated that S. voratum is well‐separated evolutionarily from other Symbiodinium spp. The motile, or mastigote, cells from different cultures were morphologically similar when observed using light, scanning, and transmission electron microscopy; and the first complete Kofoidian plate formula for a Symbiodinium sp. was characterized. As the largest of known Symbiodinium spp., the average coccoid cell diameters measured among cultured isolates ranged between 12.2 (± 0.2 SE) and 13.3 (± 0.2 SE) μm. Unique among species in the genus, a high proportion (approximately 10–20%) of cells remain motile in culture during the dark cycle. Although S. voratum occurs on surfaces of various substrates and is potentially common in the plankton of coastal areas, it may be incapable of forming stable mutualistic symbioses. 相似文献
993.
994.
Xiaowei Wang Jörg Müller Linli An Lanzhu Ji Yan Liu Xugao Wang Zhanqing Hao 《Journal of Insect Conservation》2014,18(1):85-98
In most habitats in temperate zones, species show clear intra-annual shifts in abundance and species composition. Here we aimed to present a comprehensive picture of community composition and seasonal dynamics of carabid beetles (Coleoptera: Carabidae) in broad-leaved Korean pine mixed forest in Northeast China, which harbors a large diversity. We sampled 23,336 individuals from 14 genera and 39 species with pitfall traps over more than 1 year in a 25-ha plot. The six most abundant species accounted for 76.65 % of all individuals. Species estimations for the 25 ha plot ranged from 40 to 45 species. Overall abundance, species diversity, community composition, and abundance of individual species varied seasonally. Most of the abundant species showed an activity pattern of single peak, and were most active between July and early September. Few species showed a bimodal seasonal activity pattern. Both temperature and precipitation significantly influenced the carabid community within a year. Hierarchical clustering indicated that carabid communities of ten consecutive sampling periods could be partitioned into three time-windows, respectively, corresponding with warm temperature-high rainfall season, warm temperature-low rainfall season, and cool and cold season. By using the extended method of indicator species analysis, 11 indicator species were identified for the three time-groups and their combinations, suggesting the existence of temporal niche partitioning among carabid species. We suggest that intra-annual patterns of carabid abundance and species composition can be explained by species responses to seasonal changes in hydrothermal conditions. Cost-effective sampling effort to assess native carabid diversity and assemblage was also discussed in this study. 相似文献
995.
Sarah J. Morgan Deepak A. Deshpande Brian C. Tiegs Anna M. Misior Huandong Yan Alena V. Hershfeld Thomas C. Rich Reynold A. Panettieri Steven S. An Raymond B. Penn 《The Journal of biological chemistry》2014,289(33):23065-23074
Inhaled β-agonists are effective at reversing bronchoconstriction in asthma, but the mechanism by which they exert this effect is unclear and controversial. PKA is the historically accepted effector, although this assumption is made on the basis of associative and not direct evidence. Recent studies have asserted that exchange protein activated by cAMP (Epac), not PKA, mediates the relaxation of airway smooth muscle (ASM) observed with β-agonist treatment. This study aims to clarify the role of PKA in the prorelaxant effects of β-agonists on ASM. Inhibition of PKA activity via expression of the PKI and RevAB peptides results in increased β-agonist-mediated cAMP release, abolishes the inhibitory effect of isoproterenol on histamine-induced intracellular calcium flux, and significantly attenuates histamine-stimulated MLC-20 phosphorylation. Analyses of ASM cell and tissue contraction demonstrate that PKA inhibition eliminates most, if not all, β-agonist-mediated relaxation of contracted smooth muscle. Conversely, Epac knockdown had no effect on the regulation of contraction or procontractile signaling by isoproterenol. These findings suggest that PKA, not Epac, is the predominant and physiologically relevant effector through which β-agonists exert their relaxant effects. 相似文献
996.
Iryna Benilova Rodrigo Gallardo Andreea-Alexandra Ungureanu Virginia Castillo Cano An Snellinx Meine Ramakers Carmen Bartic Frederic Rousseau Joost Schymkowitz Bart De Strooper 《The Journal of biological chemistry》2014,289(45):30977-30989
Missense mutations in alanine 673 of the amyloid precursor protein (APP), which corresponds to the second alanine of the amyloid β (Aβ) sequence, have dramatic impact on the risk for Alzheimer disease; A2V is causative, and A2T is protective. Assuming a crucial role of amyloid-Aβ in neurodegeneration, we hypothesized that both A2V and A2T mutations cause distinct changes in Aβ properties that may at least partially explain these completely different phenotypes. Using human APP-overexpressing primary neurons, we observed significantly decreased Aβ production in the A2T mutant along with an enhanced Aβ generation in the A2V mutant confirming earlier data from non-neuronal cell lines. More importantly, thioflavin T fluorescence assays revealed that the mutations, while having little effect on Aβ42 peptide aggregation, dramatically change the properties of the Aβ40 pool with A2V accelerating and A2T delaying aggregation of the Aβ peptides. In line with the kinetic data, Aβ A2T demonstrated an increase in the solubility at equilibrium, an effect that was also observed in all mixtures of the A2T mutant with the wild type Aβ40. We propose that in addition to the reduced β-secretase cleavage of APP, the impaired propensity to aggregate may be part of the protective effect conferred by A2T substitution. The interpretation of the protective effect of this mutation is thus much more complicated than proposed previously. 相似文献
997.
John Z. Wu Erik W. Sinsel Justin F. Shroyer Christopher M. Warren Daniel E. Welcome Kristin D. Zhao Kai-Nan An Frank L. Buczek 《Journal of biomechanics》2014
Previous epidemiological studies indicate that the use of thumb-push mechanical pipettes is associated with musculoskeletal disorders (MSDs) in the hand. The goal of the current study was to analyze the loading in the muscle–tendon units in the thumb during pipetting. The hand is modeled as a multi-body linkage system and includes four fingers (index, long, ring, and little finger), a thumb, and a palm segment. Since the current study is focused on the thumb, the model includes only nine muscles attached to the thumb via tendons. The time-histories of joint angles and push force at the pipette plunger during pipetting were determined experimentally and used as model input; whereas forces in the muscle–tendon units in the thumb were calculated via an inverse dynamic approach combined with an optimization procedure. Results indicate that all nine muscles have force outputs during pipetting, and the maximal force was in the abductor pollicis brevis (APB). The ratio of the mean peak muscle force to the mean peak push force during the dispensing cycle was approximately 2.3, which is comparable to values observed in grasping tasks in the literature. The analysis method and results in the current study provide a mechanistic understanding of MSD risk factors associated with pipetting, and may be useful in guiding ergonomic designs for manual pipettes. 相似文献
998.
It is difficult to study the breakdown of lumbar disc tissue over several years of exposure to bending and lifting by experimental methods. In our earlier published study we have shown how a finite element model of a healthy lumbar motion segment was used to predict the damage accumulation location and number of cyclic to failure under different loading conditions. The aim of the current study was to extend the continuum damage mechanics formulation to the degenerated discs and investigate the initiation and progression of mechanical damage. Healthy disc model was modified to represent degenerative discs (Thompson grade III and IV) by incorporating both geometrical and biochemical changes due to degeneration. Analyses predicted decrease in the number of cycles to failure with increasing severity of disc degeneration. The study showed that the damage initiated at the posterior inner annulus adjacent to the endplates and propagated outwards towards its periphery in healthy and grade III degenerated discs. The damage accumulated preferentially in the posterior region of the annulus. However in grade IV degenerated disc damage initiated at the posterior outer periphery of the annulus and propagated circumferentially. The finite element model predictions were consistent with the infrequent occurrence of rim lesions at early age but a much higher incidence in severely degenerated discs. 相似文献
999.
1000.
Zhao-Yang Li Pu-Liu Zhao-Hong Chen Feng-Hui An Li-Hua Li Li-Li Chang-Yan Guo Yan Gu Zhe Liu Tie-Bing Zhu Lian-Sheng Wang Chun-Jian Li Xiang-Qing Kong Wen-Zhu Ma Zhi-Jian Yang En-Zhi Jia 《PloS one》2014,9(10)