104 research outputs found
Molecular cloning and characterization of an acyl-ACP thioesterase gene (AhFatB1) from allotetraploid peanut (Arachis hypogaea L.)
Acyl-acyl carrier protein (ACP) thioesterase is a nuclear encoded plastid localized enzyme which plays an essential role in chain termination during de novo fatty acid synthesis in plant. FatB genes coding for this enzyme from a variety of plant species have been isolated and characterized. However, there are few reports on such genes in peanut (Arachis hypogaea), an important edible and oilseed crop. In this study, full-length cDNA of an acyl-acyl carrier protein thioesterase (EC 3.1.2.14), designated as AhFatB1, was isolated from peanut cDNA libraries. The putative open reading frames consist of 1239 bp with five introns spliced from the corresponding genomic sequence, encoding a 413 amino acid protein, two homologous genes, AhFatB1A and AhFatB1B, with sequence difference at the 5’ non-coding regions were characterized at the nucleotide level from different cultivated peanut genotypes, and the two genes have their origin in different diploid progenitor which was evidenced by the characterization of AhFatB1 genes from Arachis duranensis and Arachis ipaensis, the putative A-genome donor and B-genome donor respectively. AhFatB1 genes are constitutively expressed in peanut tissues and the total FatB1 transcript accumulations are temporally regulated during peanut seed development.Keywords: Peanut thioesterase, palmitic acid oilsee
Structural Succession of Microbial Communities in Fermented Grains for Nongxiangxing Baijiu during the Fermentation Process and Its Correlation with Physicochemical Indicators
In order to clarify the succession pattern and potential functions of the microbial communities in fermented grains for Nongxiangxing baijiu, high-throughput sequencing was used to investigate the dynamic change of microbial community structure, and the correlations between microbial community structure and physicochemical indicators were analyzed at different fermentation stages. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) was used to predict the potential functions of microbial communities in fermented grains. The results showed that Firmicutes, Proteobacteria, Actinobacteriota, Ascomycota, and Basidiomycota were the dominant phyla in fermented grains. The dominant genera were Lactobacillus, Bacillus, Staphylococcus, Thermoactinomyces, Kazachstania, Wickerhamomyces, Penicillium, Candida, Aspergillus, Meyerozyma, Debaryomyces, with Lactobacillus, Kazachstania and Wickerhamomyces being the absolutely dominant ones. The contents of reducing sugar and starch showed a significantly positive correlation with 8 bacterial genera (P < 0.05). Acidity and moisture content showed a significantly negative correlation with 10 bacterial genera. Some fungi were significantly correlated with physicochemical indicators. PICRUSt analysis showed that the relative abundance of functional enzymes was significantly different at different fermentation stages, and the dominant microorganisms in fermented grains participated in glycolysis, acid metabolism and ethanol synthesis to form a complete metabolic chain, indicating that the microbial community succession of fermented grains could be the major reason for the differences in metabolism at different fermentation stages. The findings of this study would provide a theoretical basis for the study of the metabolic mechanisms of microorganisms used for baijiu brewing
Understanding the Mechanism of Plasmon-Driven Water Splitting: Hot Electron Injection and Near Field Enhancement Effects
Utilizing plasmon-generated hot carriers to drive chemical reactions has currently become an active area of research in solar photocatalysis at the nanoscale. However, the mechanism underlying exact transfer and the generation dynamics of hot carriers, and the strategies used to further improve the quantum efficiency of the photocatalytic reaction still deserve a further look. In this work, we perform a nonadiabatic excited-state dynamics study to depict the correlation between the reaction rate of plasmon-driven water splitting (PDWS) and the sizes of gold particles, the incident light frequency and intensity, and the near-field\u27s spatial distribution. Four model systems, \ce{H2O} and \ce{Au20}@\ce{H2O} separately interacting with the laser field and the near field generated by the Au nanoparticle (NP) with a few nanometers in size, have been investigated. Our simulated results clearly unveil the mechanism of PDWS and hot-electron injection in a Schottky-free junction: the electrons populated on the antibonding orbitals of \ce{H2O} are mandatory to drive the \ce{OH} bond breaking and the strong orbital hybridization between \ce{Au20} and \ce{H2O} creates the condition for direct electron injection. We further find that the linear dependence of the reaction rate and the field amplitude only holds at a relatively weak field and it breaks down when the second {\ce{OH}} bond begins to dissociate and field-induced water fragmenting at a very intensive field, and that with the guarantee of electron injection, the water splitting rate increases with the increase of NP\u27s size. This study will be helpful for further improving the efficiency of the photochemical reactions involving the plasmon-generated hot carriers and expanding the applications of hot carriers in varieties of chemical
reactions
Numerical Simulation of One-Dimensional Fractional Nonsteady Heat Transfer Model Based on the Second Kind Chebyshev Wavelet
In the current study, a numerical technique for solving one-dimensional fractional nonsteady heat transfer model is presented. We construct the second kind Chebyshev wavelet and then derive the operational matrix of fractional-order integration. The operational matrix of fractional-order integration is utilized to reduce the original problem to a system of linear algebraic equations, and then the numerical solutions obtained by our method are compared with those obtained by CAS wavelet method. Lastly, illustrated examples are included to demonstrate the validity and applicability of the technique
Tumor-Derived Sarcopenia Factors Are Diverse in Different Tumor Types: A Pan-Cancer Analysis
Cancer-associated muscle wasting is a widespread syndrome in people with cancer and is characterized by weight loss and muscle atrophy, leading to increased morbidity and mortality. However, the tumor-derived factors that affect the development of muscle wasting and the mechanism by which they act remain unknown. To address this knowledge gap, we aimed to delineate differences in tumor molecular characteristics (especially secretion characteristics) between patients with and without sarcopenia across 10 tumor types from The Cancer Genome Atlas (TCGA). We integrated radiological characteristics from CT scans of TCGA cancer patients, which allowed us to calculate skeletal muscle area (SMA) to confirm sarcopenia. We combined TCGA and GTEx (The Genotype-Tissue Expression) data to analyze upregulated secretory genes in 10 tumor types compared with normal tissues. Upregulated secretory genes in the tumor microenvironment and their relation to SMA were analyzed to identify potential muscle wasting biomarkers (560 samples). Meanwhile, their predictive values for patient survival was validated in 3530 samples in 10 tumor types. A total of 560 participants with transcriptomic data and SMA were included. Among those, 136 participants (24.28%) were defined as having sarcopenia based on SMA. Enrichment analysis for upregulated secretory genes in cancers revealed that pathways associated with muscle wasting were strongly enriched in tumor types with a higher prevalence of sarcopenia. A series of SMA-associated secretory protein-coding genes were identified in cancers, which showed distinct gene expression profiles according to tumor type, and could be used to predict prognosis in cancers (p value ≤ 0.002). Unfortunately, those genes were different and rarely overlapped across tumor types. Tumor secretome characteristics were closely related to sarcopenia. Highly expressed secretory mediators in the tumor microenvironment were associated with SMA and could affect the overall survival of cancer patients, which may provide a valuable starting point for the further understanding of the molecular basis of muscle wasting in cancers. More importantly, tumor-derived pro-sarcopenic factors differ across tumor types and genders, which implies that mechanisms of cancer-associated muscle wasting are complex and diverse across tumors, and may require individualized treatment approaches
Experimental Study on the Road Performance of Phosphogypsum-Modified Lime-Fly Ash Stabilized Red Clay
To assess the impact of solid waste phosphogypsum on the road performance of lime-fly ash-stabilized red clay, we conducted comprehensive tests on the road performance, swelling and shrinkage characteristics, and mechanical properties of lime-fly ash soil with varying phosphogypsum content and curing age. Additionally, we analyzed the microstructure and composition changes using scanning electron microscopy and X-ray diffraction tests. The results revealed that phosphogypsum significantly enhances the early strength and moisture stability of lime-fly ash soil. The mechanical properties of lime-fly ash soil continue to improve with increased curing age, with performance improvements tapering off after 60 days and eventually stabilizing. Moreover, as the phosphogypsum content increases, the unconfined compressive strength (UCS), splitting strength, and CBR value of the lime-fly ash soil initially increase and then decrease. The optimal mixing ratio was determined to be 4% phosphogypsum, resulting in a 7-day UCS increase of 67.2%, a 28-day UCS increase of 3 times, and a 28-day splitting strength increase of 4.3 times. The moisture stability coefficient also exhibited a 43% increase after 7 days, and its anti-disintegration ability was enhanced, reaching 0.91 after 28 days, which meets the specified standards. Microscopic analysis revealed that the addition of phosphogypsum improved the overall integrity of the lime-fly ash soil, and the formation of ettringite effectively filled the soil’s pores. However, excessive ettringite caused increased expansion and deformation. To optimize the use of phosphogypsum-modified lime-fly ash-stabilized red clay as subgrade filler, it is advisable to incorporate additives to further reduce swelling deformation
A Novel Self-Adaptive Control Method for Plasma Electrolytic Oxidation Processing of Aluminum Alloys
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