排序方式: 共有109条查询结果,搜索用时 15 毫秒
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Nicholas S. Fabina Hollie M. Putnam Erik C. Franklin Michael Stat Ruth D. Gates 《Global Change Biology》2013,19(11):3306-3316
Climate change‐driven stressors threaten the persistence of coral reefs worldwide. Symbiotic relationships between scleractinian corals and photosynthetic endosymbionts (genus Symbiodinium) are the foundation of reef ecosystems, and these associations are differentially impacted by stress. Here, we couple empirical data from the coral reefs of Moorea, French Polynesia, and a network theoretic modeling approach to evaluate how patterns in coral‐Symbiodinium associations influence community stability under climate change. To introduce the effect of climate perturbations, we simulate local ‘extinctions’ that represent either the loss of coral species or the ability to engage in symbiotic interactions. Community stability is measured by determining the duration and number of species that persist through the simulated extinctions. Our results suggest that four factors greatly increase coral‐Symbiodinium community stability in response to global changes: (i) the survival of generalist hosts and symbionts maximizes potential symbiotic unions; (ii) elevated symbiont diversity provides redundant or complementary symbiotic functions; (iii) compatible symbiotic assemblages create the potential for local recolonization; and (iv) the persistence of certain traits associate with symbiotic diversity and redundancy. Symbiodinium may facilitate coral persistence through novel environmental regimes, but this capacity is mediated by symbiotic specificity, association patterns, and the functional performance of the symbionts. Our model‐based approach identifies general trends and testable hypotheses in coral‐Symbiodinium community responses. Future studies should consider similar methods when community size and/or environmental complexity preclude experimental approaches. 相似文献
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Hsan-au Wu Jeremy L. Balsbaugh Hollie Chandler Athena Georgilis Hayley Zullow Jeffrey Shabanowitz Donald F. Hunt Jesus Gil Gordon Peters Emily Bernstein 《The Journal of biological chemistry》2013,288(51):36398-36408
Cbx7 is one of five mammalian orthologs of the Drosophila Polycomb. Cbx7 recognizes methylated lysine residues on the histone H3 tail and contributes to gene silencing in the context of the Polycomb repressive complex 1 (PRC1). However, our knowledge of Cbx7 post-translational modifications remains limited. Through combined biochemical and mass spectrometry approaches, we report a novel phosphorylation site on mouse Cbx7 at residue Thr-118 (Cbx7T118ph), near the highly conserved Polycomb box. The generation of a site-specific antibody to Cbx7T118ph demonstrates that Cbx7 is phosphorylated via MAPK signaling. Furthermore, we find Cbx7T118 phosphorylation in murine mammary carcinoma cells, which can be blocked by MEK inhibitors. Upon EGF stimulation, Cbx7 interacts robustly with other members of PRC1. To test the role of Cbx7T118 phosphorylation in gene silencing, we employed a RAS-induced senescence model system. We demonstrate that Cbx7T118 phosphorylation moderately enhances repression of its target gene p16. In summary, we have identified and characterized a novel MAPK-mediated phosphorylation site on Cbx7 and propose that mitogen signaling to the chromatin template regulates PRC1 function. 相似文献
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Richard K. Amewu James Chadwick Afthab Hussain Somnath Panda Rinki Rinki Omar Janneh Stephen A. Ward Candel Miguel Hollie Burrell-Saward Livia Vivas Paul M. O’Neill 《Bioorganic & medicinal chemistry》2013,21(23):7392-7397
The synthesis of a range of mono spiro and dispiro 1,2,4,5-tetraoxane dimers is described. Selected molecules were examined in in vitro assays to determine their antimalarial and anticancer potential. Our studies reveal that several molecules possess potent nanomolar antimalarial and single digit micromolar antiproliferative IC50s versus colon (HT29-AK and leukemia (HL60) cell lines. 相似文献
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Brinker KG Garner H Wright JR 《American journal of physiology. Lung cellular and molecular physiology》2003,284(1):L232-L241
Surfactant protein A (SP-A) is an innate immune molecule that regulates pathogen clearance and lung inflammation. SP-A modulates innate immune functions such as phagocytosis, cytokine production, and chemotaxis; however, little is known about regulation of adaptive immunity by SP-A. Dendritic cells (DCs) are the most potent antigen-presenting cell with the unique capacity to activate naive T cells and initiate adaptive immunity. The goal of this study was to test the hypothesis that SP-A regulates the differentiation of immature DCs into potent T cell stimulators. The data show that incubation of immature DCs for 24 h with SP-A inhibits basal- and LPS-mediated expression of major histocompatibility complex class II and CD86. Stimulation of immature DCs by SP-A also inhibits the allostimulation of T cells, enhances dextran endocytosis, and alters DC chemotaxis toward RANTES and secondary lymphoid tissue chemokine. The effects on DC phenotype and function are similar for the structurally homologous C1q, but not for SP-D. These studies demonstrate that SP-A participates in the adaptive immune response by modulating important immune functions of DCs. 相似文献
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Skaggs HS Henry RP 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2002,133(4):605-612
Two subcellular fractions of gill tissue, cytoplasm and basolateral membranes, from two species of euryhaline decapod crustaceans, Callinectes sapidus and Carcinus maenas, acclimated to low salinity, were isolated via differential centrifugation. Carbonic anhydrase activity from both fractions was titrated against a variety of heavy metals in vitro. The metals Ag(+), Cd(2+), Cu(2+) and Zn(+) showed inhibitory action against the enzyme. Ki values for these metals against cytoplasmic CA from C. sapidus were in the range of 0.05-0.5 microM (for Ag(+), Cd(2+) and Cu(2+)) and 2-6 microM for Zn(+), some of the highest sensitivities reported for CA from an aquatic organism. The Ki values for these same metals were approximately 2-3 orders of magnitude higher for cytoplasmic CA from C. maenas, indicating that there are significant differences in heavy metal sensitivity in branchial CA from the two species, and that C. maenas possesses a metal-resistant CA isoform. It required concentrations of metals in the millimolar range, however, to inhibit CA activity from the membrane fraction of the gill of both species. There were no effects on either mortality or on hemolymph osmotic and ionic concentrations in C. maenas that were exposed to 10 microM Cd or Zn(+) at 32 per thousand salinity and subsequently transferred to 10 per thousand. The presence of a metal-resistant CA isoform in the gills of C. maenas suggests that this species would not be restricted from its normal estuarine environment by heavy metal pollution. 相似文献