32 research outputs found

    Mobilization of Lipid Stores in Manduca Sexta : Role of Adipose Triglyceride Lipase

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    Triglycerides (TG) stored in lipid droplets (LDs) are the main energy reserve in all animals. The mechanism by which animals mobilize TG is complex and not fully understood. Several proteins surrounding the LDs have been implicated in TG homeostasis such as mammalian Perilipin A and insect lipid storage proteins (Lsd). Lipid storage protein 1 (Lsd1) is a conserved insect protein and plays significant roles in the regulation of TG metabolism. Most of the knowledge on LD-associated proteins comes from studies using cells or LDs leaving biochemical properties of these proteins uncharacterized. Here we describe the purification of recombinant MsLsd1, its reconstitution in lipoprotein particles and the mutagenesis studies in putative phosphoryation sites and conserved region of Lsd1. Moreover, mobilization of TG depends on the action of lipases. The fat body triglyceride lipase from Manduca sexta, MsTGL, is the only insect lipase that has been purified and characterized, so far. This study also describes another enzyme, adipose triglyceride lipase (ATGL), and investigates a possible link between ATGL expression and nutrition levels in M.sexta. The ATGL cDNAs from M. sexta fat body encoding a 64KDa protein were cloned. Northern blot analysis detected two bands corresponding to the 3.9 and 2.4 kb transcripts, respectively. The protein sequence has the consensus lipase catalytic motif (GxSxG) and conserved "patatin-like"domain which is a key signature of ATGL enzymes isolated from other organisms. ATGL is mostly associated to the lipid droplet. Sf9 cells over-expressing the MsATGL showed lower content of cellular TG and a higher TG hydrolase activity of purified protein indicating that it is a lipase. MsATGL is up-regulated during the physiological non-feeding periods but lower than TGL with the exception of 3rd-day pre-pupal. Both levels of transcripts and expression of ATGL were dramatically up-regulated by starvation in a time-dependent manner indicating that ATGL is highly sensitive to the nutritional status of animals and may play a key role under starvation conditions. Thus, ATGL and TGL coordinately catabolize stored TGs in M.sexta. These studies provide the starting point for future studies on the mechanism and function of MsLsd1 and ATGL.Biochemistry & Molecular Biolog

    EST analysis of gene expression in the tentacle of Cyanea capillata

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    AbstractJellyfish, Cyanea capillata, has an important position in head patterning and ion channel evolution, in addition to containing a rich source of toxins. In the present study, 2153 expressed sequence tags (ESTs) from the tentacle cDNA library of C. capillata were analyzed. The initial ESTs consisted of 198 clusters and 818 singletons, which revealed approximately 1016 unique genes in the data set. Among these sequences, we identified several genes related to head and foot patterning, voltage-dependent anion channel gene and genes related to biological activities of venom. Five kinds of proteinase inhibitor genes were found in jellyfish for the first time, and some of them were highly expressed with unknown functions

    ABO genotype alters the gut microbiota by regulating GalNAc levels in pigs.

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    peer reviewedThe composition of the intestinal microbiome varies considerably between individuals and is correlated with health1. Understanding to what extend and how host genetics contributes to this variation is paramount yet has proven difficult as few associations have been replicated, particularly in humans2. We herein study the effect of host genotype on the composition of the intestinal microbiota in a large mosaic pig population. We show that, under conditions of exacerbated genetic diversity and environmental uniformity, microbiota composition and abundance of specific taxa are heritable. We map a quantitative trait locus affecting the abundance of Erysipelotrichaceae species and show that it is caused by a 2.3-Kb deletion in the N-acetyl-galactosaminyl-transferase gene underpinning the ABO blood group in humans. We show that this deletion is a ≥3.5 million years old trans-species polymorphism under balancing selection. We demonstrate that it decreases the concentrations of N-acetyl-galactosamine in the gut thereby reducing the abundance of Erysipelotrichaceae that can import and catabolize N-acetyl-galactosamine. Our results provide very strong evidence for an effect of host genotype on the abundance of specific bacteria in the intestine combined with insights in the molecular mechanisms that underpin this association. They pave the way towards identifying the same effect in human rural populations

    Effects of cement-enhanced soil on the ultimate lateral resistance of composite pile in clayey soil

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    The composite pile consisting of core-pile and surrounding cement-enhanced soil is a promising pile foundation in recent years. However, how and to what extent the cement-enhanced soil influences the ultimate lateral resistance has not been fully investigated. In this paper, the ultimate lateral resistance of the composite pile was studied by finite element limit analysis (FELA) and theoretical upper-bound analysis. The results of FELA and theoretical analysis revealed three failure modes of laterally loaded composite piles. The effects of the enhanced soil thickness, strength, and pile-enhanced soil interface characteristics on the ultimate lateral resistance were studied. The results show that increasing the enhanced soil thickness leads to a significant improvement on ultimate lateral resistance factor (NP), and there is a critical thickness beyond which the thickness no longer affects the NP. Increasing the enhanced soil strength induced 6.2%–232.6% increase of NP. However, no noticeable impact was detected when the enhanced soil strength was eight times higher than that of the natural soil. The maximum increment of NP is only 30.5% caused by the increase of interface adhesion factor (α). An empirical model was developed to calculate the NP of the composite pile, and the results show excellent agreement with the analytical results

    Public Acceptance of Driverless Buses in China: An Empirical Analysis Based on an Extended UTAUT Model

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    Driverless buses are expected to play a vital role in the future, and better public acceptance will provide a social foundation for its development. In this study, two new variables, personal innovativeness (PI) and perceived risk (PR), were incorporated into the integrated technology acceptance model (UTAUT, unified theory of acceptance and use of technology) to construct an extended model, which was then applied to explore the influencing factors for the public acceptance of driverless buses. The quality of this extended model was verified through survey data collected in Chongqing, China. The structural equation modeling (SEM) method was adopted to quantitatively describe the impact of each factor on acceptance intention (AI) as well as the mutual influence relationships between the factors. The moderating effects of demographic attributes (gender, age, and education level) on each factor in the model were also analyzed. The results showed that PI and PR are the most critical factors that affect the public’s acceptance intention; effort expectancy (EE), performance expectancy (PE), social influence (SI), and facilitating condition (FC) can also determine the acceptance intention to a certain extent; gender, age, and education level have exhibited significantly different moderating effects on the influencing factors. The explanatory power of the current research model for acceptance intention has reached 48%. This study has confirmed the applicability of the extended UTAUT model to the research of driverless bus acceptance and the research outcomes can serve as a reference basis for improving the service quality of driverless buses in China

    Asymmetry of molecular reaction dynamics of the O+DT system

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    Bufalin Inhibits Cellular Proliferation and Cancer Stem Cell-Like Phenotypes via Upregulation of MiR-203 in Glioma

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    Background/Aims: Prior studies have shown that bufalin inhibits cellular proliferation and induces apoptosis in various human cancers. MicroRNA-203 (miR-203) has been shown to function as an important regulator of tumor progression at various stages. In this study, we investigated the effect of miR-203 expression and bufalin treatment on glioma cell proliferation and stem cell-like phenotypes. Methods: We used cell viability assay, colony formation assay, cell apoptosis assay and neurosphere formation assay to dectect the treatment effect of bufalin on U251 and U87 cells. Cells were transfected with the miR-203 mimic without bufalin treatment or cells were transfected with anti-miR-203 under bufalin treatment, the above expreiments were repeated. RT-PCR was employed to quantify miR-203 expression. Western blot was performed to detect the stem cell-like (CSC) markers, OCT4 and SOX2. Luciferase activity assay was used to determine whether the SPARC is the target of miR-203. Results: Bufalin treatment inhibited cell proliferation, colony formation, and CSC phenotypes and increased cell apoptosis and expression of miR-203. Furthermore, overexpression of miR-203 led to similar outcomes as bufalin treatment with respect to the cell viability, colony formation, cell apoptosis and the phenotypes of glioma cells. While anti-miR-203 attenuated the inhibitory effects of bufalin as promoting cell proliferation, colony formation and CSC phenotyes and inhibiting cell apoptosis. In addition, we identified SPARC as a novel target gene of miR-203. Conclusions: These findings suggest that miR-203 plays an important role in bufalin’s ability to inhibit the growth of glioma cells and the development of stem cell-like phenotypes

    Au/CdS Core-Shell Sensitized Actinomorphic Flower-Like ZnO Nanorods for Enhanced Photocatalytic Water Splitting Performance

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    Herein, a novel actinomorphic flower-like ZnO/Au/CdS nanorods ternary composite photocatalyst is prepared to extend the light-responsive range, reduce the photogenerated charge carriers recombination, and ultimately improve the water splitting performance. Flower-like ZnO nanorods are synthesized by a chemical bath method and the CdS nanoparticles are sensitized by successive ionic layer adsorption and reaction method. Then the Au nanoparticles as co-catalysts are introduced by the photodeposition method to modify the interface of ZnO/CdS for reducing the photogenerated electron recombination rate and further improving the performance of water splitting. Detailed characterizations and measurements are employed to analyse the crystallinity, morphology, composition, and optical properties of the flower-like ZnO/Au/CdS nanorods samples. As a result, the flower-like ZnO/Au/CdS nanorod samples present significantly enhanced water splitting performance with a high gas evolution rate of 502.2 μmol/g/h, which is about 22.5 and 1.5 times higher than that of the pure ZnO sample and ZnO/CdS sample. The results demonstrate that the flower-like ZnO/Au/CdS nanorods ternary composite materials have great application potential in photocatalytic water splitting for the hydrogen evolution field
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