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Shi, Yu

Publications and source records attributed to Shi, Yu.

27 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

EphA7 regulates claudin6 and pronephros development in Xenopus

Highlights: • EphA7 knockdown perturbs pronephros morphogenesis and differentiation in Xenopus. • Knockdown of EphA7 reduces membrane CLDN6 level in the pronephros tubule cells. • EphA7 phosphorylates and destabilizes membrane CLDN6 in cultured cells. • A soluble form of EphA7 stabilizes CLDN6 and antagonizes EphA7. Eph/ephrin molecules are widely expressed during embryonic development, and function in a variety of developmental processes. Here we studied the roles of the Eph receptor EphA7 and its soluble form in Xenopus pronephros development. EphA7 is specifically expressed in pronephric tubules at tadpole stages and knockdown of EphA7 by a translation blocking morpholino led to defects in tubule cell differentiation and morphogenesis. A soluble form of EphA7 (sEphA7) was also identified. Interestingly, the membrane level of claudin6 (CLDN6), a tetraspan transmembrane tight junction protein, was dramatically reduced in the translation blocking morpholino injected embryos, but not when a splicing morpholino was used, which blocks only the full length EphA7. In cultured cells, EphA7 binds and phosphorylates CLDN6, and reduces its distribution at the cell surface. Our work suggests a role of EphA7 in the regulation of cell adhesion during pronephros development, whereas sEphA7 works as an antagonist.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Dramatic Increases of Soil Microbial Functional Gene Diversity at the Treeline Ecotone of Changbai Mountain

The elevational and latitudinal diversity patterns of microbial taxa have attracted great attention in the past decade. Recently, the distribution of functional attributes has been in the spotlight. Here, we report a study profiling soil microbial communities along an elevation gradient (500-2200 m) on Changbai Mountain. Using a comprehensive functional gene microarray (GeoChip 5.0), we found that microbial functional gene richness exhibited a dramatic increase at the treeline ecotone, but the bacterial taxonomic and phylogenetic diversity based on 16S rRNA gene sequencing did not exhibit such a similar trend. However, the β-diversity (compositional dissimilarity among sites) pattern for both bacterial taxa and functional genes was similar, showing significant elevational distance-decay patterns which presented increased dissimilarity with elevation. The bacterial taxonomic diversity/structure was strongly influenced by soil pH, while the functional gene diversity/structure was significantly correlated with soil dissolved organic carbon (DOC). This finding highlights that soil DOC may be a good predictor in determining the elevational distribution of microbial functional genes. The finding of significant shifts in functional gene diversity at the treeline ecotone could also provide valuable information for predicting the responses of microbial functions to climate change.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2016

Carbon constrains fungal endophyte assemblages along the timberline

Summary The alpha diversity of foliar fungal endophytes ( FEs ) in leaves of B etula ermanii in a subalpine timberline ecotone on C hangbai M ountain, C hina increased with elevation. There were also significant differences in beta diversity along the elevation gradient. Among the environmental variables analysed, leaf carbon significantly increased with elevation, and was the most significant environmental factor that constrained the alpha and beta diversity in the FE communities. Tree height and the cellulose, lignin, and carbon/nitrogen ratio of the leaves also affected the FE assemblages. When controlled for the effects of elevation, leaf carbon was still the main driver of changes in evenness, Shannon diversity and FE community composition. The results offered clues of the carbon acquisition strategy of the foliar FEs across this cold terrain. There was strong multicollinearity between both annual precipitation and temperature, with elevation (| P earson r| > 0.986), so the effects of these climatic variables were impossible to separate; however, they may play key roles, and the direct effects of both warrant further investigation. As pioneer decomposers of leaf litter, variations in diversity and community composition of FE measured here may feedback and influence carbon cycling and dynamics in these forest ecosystems.

Yang, Teng↗
DOE OSTI2016

Dynamic non-reciprocal meta-surfaces with arbitrary phase reconfigurability based on photonic transition in meta-atoms

We introduce a distinct class of dynamic non-reciprocal meta-surfaces with arbitrary phase-reconfigurability. This meta-surface consists of an array of meta-atoms, each of which is subject to temporal refractive index modulation, which induces photonic transitions between the states of the meta-atom. We show that arbitrary phase profile for the outgoing wave can be achieved by controlling the phase of the modulation at each meta-atom. Moreover, such dynamic meta-surfaces exhibit non-reciprocal response without the need for magneto-optical effects. The use of photonic transition significantly enhances the tunability and the possible functionalities of meta-surfaces.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

The links between ecosystem multifunctionality and above- and belowground biodiversity are mediated by climate

Plant biodiversity is often correlated with ecosystem functioning in terrestrial ecosystems. However, we know little about the relative and combined effects of above- and belowground biodiversity on multiple ecosystem functions (for example, ecosystem multifunctionality, EMF) or how climate might mediate those relationships. Here we tease apart the effects of biotic and abiotic factors, both above- and belowground, on EMF on the Tibetan Plateau, China. We found that a suite of biotic and abiotic variables account for up to 86% of the variation in EMF, with the combined effects of above- and belowground biodiversity accounting for 45% of the variation in EMF. Our results have two important implications: first, including belowground biodiversity in models can improve the ability to explain and predict EMF. Second, regional-scale variation in climate, and perhaps climate change, can determine, or at least modify, the effects of biodiversity on EMF in natural ecosystems.

59 BASIC BIOLOGICAL SCIENCES↗