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991.
S. D. Ohdachi M. Hasegawa M. A. Iwasa P. Vogel T. Oshida L.-K. Lin & H. Abe 《Journal of Zoology》2006,270(1):199-200
Molecular phylogeny of soricid shrews (Soricidae, Eulipotyphla, Mammalia) based on 1140 bp mitochondrial cytochrome b gene (cyt b ) sequences was inferred by the maximum likelihood (ML) method. All 13 genera of extant Soricinae and two genera of Crocidurinae were included in the analyses. Anourosorex was phylogenetically distant from the main groupings within Soricinae and Crocidurinae in the ML tree. Thus, it could not be determined to which subfamily Anourosorex should be assigned: Soricinae, Crocidurinae or a new subfamily. Soricinae (excluding Anourosorex ) should be divided into four tribes: Neomyini, Notiosoricini, Soricini and Blarinini. However, monophyly of Blarinini was not robust in the present data set. Also, branching orders among tribes of Soricinae and those among genera of Neomyini could not be determined because of insufficient phylogenetic information of the cyt b sequences. For water shrews of Neomyini ( Chimarrogale , Nectogale and Neomys ), monophyly of Neomys and the Chimarrogale – Nectogale group could not be verified, which implies the possibility of multiple origins for the semi-aquatic mode of living among taxa within Neomyini. Episoriculus may contain several separate genera. Blarinella was included in Blarinini not Soricini, based on the cyt b sequences, but the confidence level was rather low; hence more phylogenetic information is needed to determine its phylogenetic position. Furthermore, some specific problems of taxonomy of soricid shrews were clarified, for example phylogeny of local populations of Notiosorex crawfordi , Chimarrogale himalayica and Crocidura attenuata . 相似文献
992.
Cécile Muller Iel-Soo Bang Jyoti Velayudhan Joyce Karlinsey Kai Papenfort Jörg Vogel Ferric C. Fang 《Molecular microbiology》2009,71(5):1228-1238
The alternative sigma factor σE is activated by unfolded outer membrane proteins (OMPs) and plays an essential role in Salmonella pathogenesis. The canonical pathway of σE activation in response to envelope stress involves sequential proteolysis of the anti-sigma factor RseA by the PDZ proteases DegS and RseP. Here we show that σE in Salmonella enterica sv. Typhimurium can also be activated by acid stress. A σE -deficient mutant exhibits increased susceptibility to acid pH and reduced survival in an acidified phagosomal vacuole. Acid activation of σE -dependent gene expression is independent of the unfolded OMP signal or the DegS protease but requires processing of RseA by RseP. The RseP PDZ domain is indispensable for acid induction, suggesting that acid stress may disrupt an inhibitory interaction between RseA and the RseP PDZ domain to allow RseA proteolysis in the absence of antecedent action of DegS. These observations demonstrate a novel environmental stimulus and activation pathway for the σE regulon that appear to be critically important during Salmonella –host cell interactions. 相似文献
993.
Michael Siu Theodore O. Johnson Yong Wang Sajiv K. Nair Wendy D. Taylor Stephan J. Cripps Jean J. Matthews Martin P. Edwards Thomas A. Pauly Jacques Ermolieff Arturo Castro Natilie A. Hosea Amy LaPaglia Andrea N. Fanjul Jennifer E. Vogel 《Bioorganic & medicinal chemistry letters》2009,19(13):3493-3497
N-(Pyridin-2-yl) arylsulfonamides are identified as inhibitors of 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1), an enzyme that catalyzes the reduction of the glucocorticoid cortisone to cortisol. Dysregulation of glucocorticoids has been implicated in the pathogenesis of diabetes and the metabolic syndrome. In this Letter, we present the development of an initial lead to an efficient ligand with improved physiochemical properties using a deletion strategy. This strategy allowed for further optimization of potency leading to the discovery of the clinical candidate PF-915275. 相似文献
994.
ATP synthases from coupling membranes are complex rotary motors that convert the energy of proton gradients across coupling membranes into the chemical potential of the β-γ anhydride bond of ATP. Proton movement within the ring of c subunits localized in the F0-sector drives γ and ɛ rotation within the F1α3β3 catalytic core where substrates are bound and products are released. An external stalk composed of homodimeric subunits b2 in Escherichia coli or heterodimeric bb′ in photosynthetic synthases connects F0 subunit a with F1 subunits δ and most likely α. The external stalk resists rotation, and is of interest both functionally and structurally. Hypotheses that the external stalk contributes to the overall efficiency of the reaction through elastic coupling of rotational substeps, and that stalks form staggered, right-handed coiled coils, are investigated here. We report on different structures that accommodate heptad discontinuities with either local or global underwinding. Analyses of the knob-and-hole packing of the E. coli b2 and Synechocystis bb′ stalks strongly support the possibility that these proteins can adopt conventional left-handed coiled coils. 相似文献
995.
Valentina Tremaroli Matthew L. Workentine Aalim M. Weljie Hans J. Vogel Howard Ceri Carlo Viti Enrico Tatti Ping Zhang Alexander P. Hynes Raymond J. Turner Davide Zannoni 《Applied microbiology》2009,75(3):719-728
Pseudomonas pseudoalcaligenes KF707 is naturally resistant to the toxic metalloid tellurite, but the mechanisms of resistance are not known. In this study we report the isolation of a KF707 mutant (T5) with hyperresistance to tellurite. In order to characterize the bacterial response and the pathways leading to tolerance, we utilized Phenotype MicroArray technology (Biolog) and a metabolomic technique based on nuclear magnetic resonance spectroscopy. The physiological states of KF707 wild-type and T5 cells exposed to tellurite were also compared in terms of viability and reduced thiol content. Our analyses showed an extensive change in metabolism upon the addition of tellurite to KF707 cultures as well as different responses when the wild-type and T5 strains were compared. Even in the absence of tellurite, T5 cells displayed a “poised” physiological status, primed for tellurite exposure and characterized by altered intracellular levels of glutathione, branched-chain amino acids, and betaine, along with increased resistance to other toxic metals and metabolic inhibitors. We conclude that hyperresistance to tellurite in P. pseudoalcaligenes KF707 is correlated with the induction of the oxidative stress response, resistance to membrane perturbation, and reconfiguration of cellular metabolism. 相似文献
996.
997.
Maria Paola Paronetto Valeria Messina Enrica Bianchi Marco Barchi Gillian Vogel Costanzo Moretti Fioretta Palombi Mario Stefanini Raffaele Geremia Stéphane Richard Claudio Sette 《The Journal of cell biology》2009,185(2):235-249
Sam68 is a KH-type RNA-binding protein involved in several steps of RNA metabolism with potential implications in cell differentiation and cancer. However, its physiological roles are still poorly understood. Herein, we show that Sam68−/− male mice are infertile and display several defects in spermatogenesis, demonstrating an essential role for Sam68 in male fertility. Sam68−/− mice produce few spermatozoa, which display dramatic motility defects and are unable to fertilize eggs. Expression of a subset of messenger mRNAs (mRNAs) is affected in the testis of knockout mice. Interestingly, Sam68 is associated with polyadenylated mRNAs in the cytoplasm during the meiotic divisions and in round spermatids, when it interacts with the translational machinery. We show that Sam68 is required for polysomal recruitment of specific mRNAs and for accumulation of the corresponding proteins in germ cells and in a heterologous system. These observations demonstrate a novel role for Sam68 in mRNA translation and highlight its essential requirement for the development of a functional male gamete. 相似文献
998.
Lin H Fridy PC Ribeiro AA Choi JH Barma DK Vogel G Falck JR Shears SB York JD Mayr GW 《The Journal of biological chemistry》2009,284(3):1863-1872
We have characterized the positional specificity of the mammalian and yeast VIP/diphosphoinositol pentakisphosphate kinase (PPIP5K) family of inositol phosphate kinases. We deployed a microscale metal dye detection protocol coupled to a high performance liquid chromatography system that was calibrated with synthetic and biologically synthesized standards of inositol pyrophosphates. In addition, we have directly analyzed the structures of biological inositol pyrophosphates using two-dimensional 1H-1H and 1H-31P nuclear magnetic resonance spectroscopy. Using these tools, we have determined that the mammalian and yeast VIP/PPIP5K family phosphorylates the 1/3-position of the inositol ring in vitro and in vivo. For example, the VIP/PPIP5K enzymes convert inositol hexakisphosphate to 1/3-diphosphoinositol pentakisphosphate. The latter compound has not previously been identified in any organism. We have also unequivocally determined that 1/3,5-(PP)2-IP4 is the isomeric structure of the bis-diphosphoinositol tetrakisphosphate that is synthesized by yeasts and mammals, through a collaboration between the inositol hexakisphosphate kinase and VIP/PPIP5K enzymes. These data uncover phylogenetic variability within the crown taxa in the structures of inositol pyrophosphates. For example, in the Dictyostelids, the major bis-diphosphoinositol tetrakisphosphate is 5,6-(PP)2-IP4 ( Laussmann, T., Eujen, R., Weisshuhn, C. M., Thiel, U., Falck, J. R., and Vogel, G. (1996) Biochem. J. 315, 715-725 ). Our study brings us closer to the goal of understanding the structure/function relationships that control specificity in the synthesis and biological actions of inositol pyrophosphates. 相似文献
999.
江西齐云山自然保护区鸟类区系与多样性分析 总被引:5,自引:1,他引:4
2006年11月和2007年2~9月,对齐云山保护区的鸟类进行了本底调查和物种监测,共记录到鸟类257种,隶属于17目54科.其中留鸟120种,候鸟(夏候鸟、冬候鸟和旅鸟)137种;古北界种类97种(37.7%),东洋界种类141种(54.9%),广布种有19种(7.4%);国家重点保护鸟类8科34种;发现江西省新纪录鸟类4种.多样性分析结果显示,该区鸟类群落Shannon-Wiener指数、Pielou指数、和Simpson指数分别为3.875、0.791和0.964.从各生境群落多样性指数看,农田居民区中鸟类群落多样性指数最大,其次是灌草丛和阔叶林,溪流水域的多样性指数最小;优势度指数在不同生境的变化趋势与群落多样性指数相似;灌草丛中鸟类群落均匀度指数最高,阔叶林中的鸟类群落均匀度指数最低.通过与周边包括九连山、井冈山、江西武夷山和广东车八岭4个保护区的鸟类进行物种多样性G-F指数对比分析,得出齐云山鸟类多样性与九连山相当,而高于其他3个保护区. 相似文献
1000.