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排序方式: 共有46条查询结果,搜索用时 15 毫秒
11.
A pigment-binding protein essential for regulation of photosynthetic light harvesting 总被引:58,自引:0,他引:58
Photosynthetic light harvesting in plants is regulated in response to changes in incident light intensity. Absorption of light that exceeds a plant's capacity for fixation of CO2 results in thermal dissipation of excitation energy in the pigment antenna of photosystem II by a poorly understood mechanism. This regulatory process, termed nonphotochemical quenching, maintains the balance between dissipation and utilization of light energy to minimize generation of oxidizing molecules, thereby protecting the plant against photo-oxidative damage. To identify specific proteins that are involved in nonphotochemical quenching, we have isolated mutants of Arabidopsis thaliana that cannot dissipate excess absorbed light energy. Here we show that the gene encoding PsbS, an intrinsic chlorophyll-binding protein of photosystem II, is necessary for nonphotochemical quenching but not for efficient light harvesting and photosynthesis. These results indicate that PsbS may be the site for nonphotochemical quenching, a finding that has implications for the functional evolution of pigment-binding proteins. 相似文献
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13.
Chienming Chen Chihchia Chen Tsanhuang Shih Tunwen Pai Chinhua Hu Wenshyong Tzou 《系统科学与复杂性》2010,23(5):906-916
Dynamic mutations of simple sequence repeats (SSRs) have been demonstrated to affect normal gene function and cause different
genetic disorders. Several conserved and even partial functional SSR patterns are discovered in inherited orthologous disease
genes. To explore a wide range of SSRs in genetic diseases, a comprehensive system focusing on identifying orthologous SSRs
of disease genes through a comparative genomics mechanism is constructed and accomplished by adopting online Mendelian inheritance
in man (OMIM) and NCBI HomoloGene databases as the fundamental resources of human genetic diseases and homologous gene information.
In addition, an efficient and effective algorithm for searching SSR patterns is also developed for providing annotated SSR
information among various model species. By integrating these data resources and mining technologies, biologists and doctors
can systematically retrieve novel and important conserved SSR information among orthologous disease genes. The proposed system,
Orthologous SSR for Disease Genes (OSDG), is the first comprehensive framework for identifying orthologous SSRs as potential
causative factors of genetic disorders and is freely available at . 相似文献
14.
Yoshida K Sanada M Shiraishi Y Nowak D Nagata Y Yamamoto R Sato Y Sato-Otsubo A Kon A Nagasaki M Chalkidis G Suzuki Y Shiosaka M Kawahata R Yamaguchi T Otsu M Obara N Sakata-Yanagimoto M Ishiyama K Mori H Nolte F Hofmann WK Miyawaki S Sugano S Haferlach C Koeffler HP Shih LY Haferlach T Chiba S Nakauchi H Miyano S Ogawa S 《Nature》2011,478(7367):64-69
Myelodysplastic syndromes and related disorders (myelodysplasia) are a heterogeneous group of myeloid neoplasms showing deregulated blood cell production with evidence of myeloid dysplasia and a predisposition to acute myeloid leukaemia, whose pathogenesis is only incompletely understood. Here we report whole-exome sequencing of 29 myelodysplasia specimens, which unexpectedly revealed novel pathway mutations involving multiple components of the RNA splicing machinery, including U2AF35, ZRSR2, SRSF2 and SF3B1. In a large series analysis, these splicing pathway mutations were frequent (~45 to ~85%) in, and highly specific to, myeloid neoplasms showing features of myelodysplasia. Conspicuously, most of the mutations, which occurred in a mutually exclusive manner, affected genes involved in the 3'-splice site recognition during pre-mRNA processing, inducing abnormal RNA splicing and compromised haematopoiesis. Our results provide the first evidence indicating that genetic alterations of the major splicing components could be involved in human pathogenesis, also implicating a novel therapeutic possibility for myelodysplasia. 相似文献
15.
Bonnin A Goeden N Chen K Wilson ML King J Shih JC Blakely RD Deneris ES Levitt P 《Nature》2011,472(7343):347-350
Serotonin (5-hydroxytryptamine or 5-HT) is thought to regulate neurodevelopmental processes through maternal-fetal interactions that have long-term mental health implications. It is thought that beyond fetal 5-HT neurons there are significant maternal contributions to fetal 5-HT during pregnancy but this has not been tested empirically. To examine putative central and peripheral sources of embryonic brain 5-HT, we used Pet1(-/-) (also called Fev) mice in which most dorsal raphe neurons lack 5-HT. We detected previously unknown differences in accumulation of 5-HT between the forebrain and hindbrain during early and late fetal stages, through an exogenous source of 5-HT which is not of maternal origin. Using additional genetic strategies, a new technology for studying placental biology ex vivo and direct manipulation of placental neosynthesis, we investigated the nature of this exogenous source. We uncovered a placental 5-HT synthetic pathway from a maternal tryptophan precursor in both mice and humans. This study reveals a new, direct role for placental metabolic pathways in modulating fetal brain development and indicates that maternal-placental-fetal interactions could underlie the pronounced impact of 5-HT on long-lasting mental health outcomes. 相似文献
16.
Li W Bloom JS Podsiadlowski P Miller AA Cenko SB Jha SW Sullivan M Howell DA Nugent PE Butler NR Ofek EO Kasliwal MM Richards JW Stockton A Shih HY Bildsten L Shara MM Bibby J Filippenko AV Ganeshalingam M Silverman JM Kulkarni SR Law NM Poznanski D Quimby RM McCully C Patel B Maguire K Shen KJ 《Nature》2011,480(7377):348-350
Type Ia supernovae are thought to result from a thermonuclear explosion of an accreting white dwarf in a binary system, but little is known of the precise nature of the companion star and the physical properties of the progenitor system. There are two classes of models: double-degenerate (involving two white dwarfs in a close binary system) and single-degenerate models. In the latter, the primary white dwarf accretes material from a secondary companion until conditions are such that carbon ignites, at a mass of 1.38 times the mass of the Sun. The type Ia supernova SN 2011fe was recently detected in a nearby galaxy. Here we report an analysis of archival images of the location of SN 2011fe. The luminosity of the progenitor system (especially the companion star) is 10-100 times fainter than previous limits on other type Ia supernova progenitor systems, allowing us to rule out luminous red giants and almost all helium stars as the mass-donating companion to the exploding white dwarf. 相似文献
17.
Chi‐Hsiang Chu Mong‐Na Lo Huang Shih‐Feng Huang Ray‐Bing Chen 《Journal of forecasting》2019,38(5):422-439
A vector autoregression (VAR) model is powerful for analyzing economic data as it can be used to simultaneously handle multiple time series from different sources. However, in the VAR model, we need to address the problem of substantial coefficient dimensionality, which would cause some computational problems for coefficient inference. To reduce the dimensionality, one could take model structures into account based on prior knowledge. In this paper, group structures of the coefficient matrices are considered. Because of the different types of VAR structures, corresponding Markov chain Monte Carlo algorithms are proposed to generate posterior samples for performing inference of the structure selection. Simulation studies and a real example are used to demonstrate the performances of the proposed Bayesian approaches. 相似文献
18.
Effects of the organophosphate neurotoxin soman on rat mesenteric mast cell granule content were determined using scanning-integrating microdensitometric analysis of individual cell metachromasia. Mast cell degranulation was evidenced both with sublethal (0.5 LD50) and lethal (1.5 LD50) dosages and as early as 3-10 min post-injection. These data indicate a possible contribution of mast cell autacoids in the genesis of organophosphate-induced respiratory and circulatory collapse. 相似文献
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20.
Multiple forms of monoamine oxidase in the developing brain 总被引:2,自引:0,他引:2