914 research outputs found

    Acetoin Catabolism and Acetylbutanediol Formation by Bacillus pumilus in a Chemically Defined Medium

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    BACKGROUND: Most low molecular diols are highly water-soluble, hygroscopic, and reactive with many organic compounds. In the past decades, microbial research to produce diols, e.g. 1,3-propanediol and 2,3-butanediol, were considerably expanded due to their versatile usages especially in polymer synthesis and as possible alternatives to fossil based feedstocks from the bioconversion of renewable natural resources. This study aimed to provide a new way for bacterial production of an acetylated diol, i.e. acetylbutanediol (ABD, 3,4-dihydroxy-3-methylpentan-2-one), by acetoin metabolism. METHODOLOGY/PRINCIPAL FINDINGS: When Bacillus pumilus ATCC 14884 was aerobically cultured in a chemically defined medium with acetoin as the sole carbon and energy source, ABD was produced and identified by gas chromatography--chemical ionization mass spectrometry and NMR spectroscopy. CONCLUSIONS/SIGNIFICANCE: Although the key enzyme leading to ABD from acetoin has not been identified yet at this stage, this study proposed a new metabolic pathawy to produce ABD in vivo from using renewable resources--in this case acetoin, which could be reproduced from glucose in this study--making it the first facility in the world to prepare this new bio-based diol product

    Identification of random amplified polymorphic DNA (RAPD) marker of Ph-3 gene for late blight resistance in tomato

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    Late blight is a highly destructive disease of tomato worldwide. Host resistance is the most effective method for disease control. The application of molecular markers is an efficient way to identify host resistance for breeding programs. In this study, bulked segregant analysis (BSA) was used to search for random amplified polymorphic DNA (RAPD) markers linked to the late blight resistance gene Ph-3, using an F2 population (147 individuals) derived from a cross of tomato lines CLN2037 (resistant) and T2-03 (susceptible). Two hundred and thirty decamer primers with arbitrary sequences were chosen for polymerase chain reaction amplification. One RAPD marker CCPB272-03740 (primer sequence GGTCGATCTG) was found to be tightly linked to the resistance gene Ph-3 and was located 5.8 cm from the resistance gene. Marker CCPB272-03740 is the first marker of gene Ph-3 based on PCR reaction.Key words: Tomato, late blight, random amplified polymorphic DNA (RAPD) marker, gene Ph-3

    Analysis of small RNAs revealed differential expressions during pollen and embryo sac development in autotetraploid rice

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    Protein-protein interaction of meiosis-related genes with the targets predicted by the DEM associated with meiosis. Table S18. 21 nt-phasiRNAs triggered by the miR2118. Table S19. 24 nt-phasiRNAs triggered by the miR2275. Table S20. Overview of 24 nt TEs-siRNAs during pollen and embryo sac development of 02428-4x and 02428-2x. Table S21. Distribution of 24 nt TEs-siRNAs in autotetraploid and diploid rice. Table S22. Differentially expressed 24 nt TEs-siRNAs during pollen and embryo sac development of autotetraploid rice. Table S23. Anther length during pollen development stages in autotetraploid and diploid rice. Table S24. The stem–loop RT primers used in the present study. (XLSX 1012 kb

    Electric-field Control of Magnetism with Emergent Topological Hall Effect in SrRuO3 through Proton Evolution

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    Ionic substitution forms an essential pathway to manipulate the carrier density and crystalline symmetry of materials via ion-lattice-electron coupling, leading to a rich spectrum of electronic states in strongly correlated systems. Using the ferromagnetic metal SrRuO3 as a model system, we demonstrate an efficient and reversible control of both carrier density and crystalline symmetry through the ionic liquid gating induced protonation. The insertion of protons electron-dopes SrRuO3, leading to an exotic ferromagnetic to paramagnetic phase transition along with the increase of proton concentration. Intriguingly, we observe an emergent topological Hall effect at the boundary of the phase transition as the consequence of the newly-established Dzyaloshinskii-Moriya interaction owing to the breaking of inversion symmetry in protonated SrRuO3 with the proton compositional film-depth gradient. We envision that electric-field controlled protonation opens a novel strategy to design material functionalities

    MoocRadar: A Fine-grained and Multi-aspect Knowledge Repository for Improving Cognitive Student Modeling in MOOCs

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    Student modeling, the task of inferring a student's learning characteristics through their interactions with coursework, is a fundamental issue in intelligent education. Although the recent attempts from knowledge tracing and cognitive diagnosis propose several promising directions for improving the usability and effectiveness of current models, the existing public datasets are still insufficient to meet the need for these potential solutions due to their ignorance of complete exercising contexts, fine-grained concepts, and cognitive labels. In this paper, we present MoocRadar, a fine-grained, multi-aspect knowledge repository consisting of 2,513 exercise questions, 5,600 knowledge concepts, and over 12 million behavioral records. Specifically, we propose a framework to guarantee a high-quality and comprehensive annotation of fine-grained concepts and cognitive labels. The statistical and experimental results indicate that our dataset provides the basis for the future improvements of existing methods. Moreover, to support the convenient usage for researchers, we release a set of tools for data querying, model adaption, and even the extension of our repository, which are now available at https://github.com/THU-KEG/MOOC-Radar.Comment: Accepted by SIGIR 202

    Undernutrition-induced substance metabolism and energy production disorders affected the structure and function of the pituitary gland in a pregnant sheep model

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    IntroductionUndernutrition spontaneously occurs in ewes during late gestation and the pituitary is an important hinge in the neurohumoral regulatory system. However, little is known about the effect of undernutrition on pituitary metabolism.MethodsHere, 10 multiparous ewes were restricted to a 30% feeding level during late gestation to establish an undernutrition model while another 10 ewes were fed normally as controls. All the ewes were sacrificed, and pituitary samples were collected to perform transcriptome, metabolome, and quantitative real-time PCR analysis and investigate the metabolic changes.ResultsPCA and PLS-DA of total genes showed that undernutrition changed the total transcriptome profile of the pituitary gland, and 581 differentially expressed genes (DEGs) were identified between the two groups. Clusters of orthologous groups for eukaryotic complete genomes demonstrated that substance transport and metabolism, including lipids, carbohydrates, and amino acids, energy production and conversion, ribosomal structure and biogenesis, and the cytoskeleton were enriched by DEGs. Kyoto encyclopedia of genes and genomes pathway enrichment analysis displayed that the phagosome, intestinal immune network, and oxidative phosphorylation were enriched by DEGs. Further analysis found that undernutrition enhanced the lipid degradation and amino acid transport, repressing lipid synthesis and transport and amino acid degradation of the pituitary gland. Moreover, the general metabolic profiles and metabolic pathways were affected by undernutrition, repressing the 60S, 40S, 28S, and 39S subunits of the ribosomal structure for translation and myosin and actin synthesis for cytoskeleton. Undernutrition was found also to be implicated in the suppression of oxidative phosphorylation for energy production and conversion into a downregulation of genes related to T cell function and the immune response and an upregulation of genes involved in inflammatory reactions enriching phagosomes.DiscussionThis study comprehensively analyses the effect of undernutrition on the pituitary gland in a pregnant sheep model, which provides a foundation for further research into the mechanisms of undernutrition-caused hormone secretion and metabolic disorders

    Xiao-Ai-Ping, a TCM Injection, Enhances the Antigrowth Effects of Cisplatin on Lewis Lung Cancer Cells through Promoting the Infiltration and Function of CD8 +

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    Objectives. To investigate how Xiao-Ai-Ping injection, a traditional Chinese medicine and an ancillary drug in tumor treatment, enhances the antitumor effects of cisplatin on Lewis lung cancer (LLC) cells. Methods. LLC-bearing mice were daily intraperitoneally injected with various doses of cisplatin, Xiao-Ai-Ping, or cisplatin plus Xiao-Ai-Ping, respectively. Body weight and tumor volumes were measured every three days. Results. Combination of Xiao-Ai-Ping and cisplatin yielded significantly better antigrowth and proapoptotic effects on LLC xenografts than sole drug treatment did. In addition, we found that Xiao-Ai-Ping triggered the infiltration of CD8+ T cells, a group of cytotoxic T cells, to LLC xenografts. Furthermore, the mRNA levels of interferon-γ (ifn-γ), perforin-1 (prf-1), and granzyme B (gzmb) in CD8+ T cells were significantly increased after combination treatment of Xiao-Ai-Ping and cisplatin. In vitro studies showed that Xiao-Ai-Ping markedly upregulated the mRNA levels of ifn-γ, prf-1, and gzmb in CD8+ T cells in a concentration-dependent manner, suggesting that Xiao-Ai-Ping augments the function of CD8+ T cells. Conclusions. Xiao-Ai-Ping promotes the infiltration and function of CD8+ T cells and thus enhances the antigrowth effects of cisplatin on LLC xenografts, which provides new evidence for the combination of Xiao-Ai-Ping and cisplatin in clinic in China
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