Intracellular cholesterol redistribution between membranes and its subsequent esterification are critical aspects of lipid homeostasis that prevent free sterol toxicity. To identify genes that mediate sterol trafficking, we screened for yeast mutants that were inviable in the absence of sterol esterification. Mutations in the novel gene, ARV1, render cells dependent on sterol esterification for growth, nystatin-sensitive, temperaturesensitive, and anaerobically inviable. Cells lacking Arv1p display altered intracellular sterol distribution and are defective in sterol uptake, consistent with a role for Arv1p in trafficking sterol into the plasma membrane. Human ARV1, a predicted sequence ortholog of yeast ARV1, complements the defects associated with deletion of the yeast gene. The genes are predicted to encode transmembrane proteins with potential zincbinding motifs. We propose that ARV1 is a novel mediator of eukaryotic sterol homeostasis.Sterols are essential structural and regulatory components of eukaryotic cellular membranes (1, 2). However, cholesterol over-accumulation is cytotoxic (3), necessitating mechanisms to maintain this metabolite at appropriate levels. A pivotal component of this homeostasis is the esterification of free sterol by acyl-coenzyme A:cholesterol O-acyltransferase (ACAT) 1 (4, 5).Indeed, the inhibition of ACAT in sterol-loaded cells induces cell death when extracellular sterol acceptors such as high density lipoproteins are absent (6, 7). Intracellular cholesterol redistribution mediates a number of responses to elevated free sterol levels. These include elevated ACAT activity, down-regulated sterol and fatty acid biosynthesis, and reduced lipoprotein uptake via LDL receptors (8, 9). The latter two events reflect changes in transcriptional activation by sterol regulatory element-binding proteins (SREBPs) in response to sterol accumulation in regulatory pools (9), whereas ACAT activity is allosterically regulated by substrate supply (10). Sterols are maintained at a high concentration in the plasma membrane (PM) relative to the endoplasmic reticulum (ER) (1, 2), where SREBP and ACAT reside. Thus trafficking of sterol to and from the ER is a critical component of sterol homeostasis.The process of sterol trafficking is poorly understood at the molecular level. In certain cell types, caveolin influences what has been termed "fast" movement of cholesterol to plasma membrane cholesterol-rich microdomains (caveolae) (11,12). Mutations in the Niemann Pick type C (NPC1) gene result in accumulation of LDL-derived cholesterol in the lysosome (13, 14). However, not all cells express caveolin, and the movement of endogenously synthesized cholesterol to the plasma membrane in NPC1-deficient cells is normal (15).To identify novel genes that mediate sterol trafficking in all higher cells, we utilized the genetically tractable model eukaryote, Saccharomyces cerevisiae (budding yeast). We reasoned that dependence on sterol esterification for viability would be one criterion for identifying novel sterol...

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The AP2/ERF superfamily is a large, plant-specific transcription factor family that is involved in many important processes, including plant growth, development, and stress responses. Using Medicago truncatula genome information, we identified and characterized 123 putative AP2/ERF genes, which were named as MtERF1–123. These genes were classified into four families based on phylogenetic analysis, which is consistent with the results of other plant species. MtERF genes are distributed throughout all chromosomes but are clustered on various chromosomes due to genomic tandem and segmental duplication. Using transcriptome, high-throughput sequencing data, and qRT-PCR analysis, we assessed the expression patterns of the MtERF genes in tissues during development and under abiotic stresses. In total, 87 MtERF genes were expressed in plant tissues, most of which were expressed in specific tissues during development or under specific abiotic stress treatments. These results support the notion that MtERF genes are involved in developmental regulation and environmental responses in M. truncatula. Furthermore, a cluster of DREB subfamily members on chromosome 6 was induced by both cold and freezing stress, representing a positive gene regulatory response under low temperature stress, which suggests that these genes might contribute to freezing tolerance to M. truncatula. In summary, our genome-wide characterization, evolutionary analysis, and expression pattern analysis of MtERF genes in M. truncatula provides valuable information for characterizing the molecular functions of these genes and utilizing them to improve stress tolerance in plants.

Ostwald ripening, the interfacial-energy-driven dissolution and reprecipitation of solutes, becomes an increasingly significant problem for nanoparticle formulations. We present the first quantitative study of Ostwald ripening for nanoparticle dispersions. The Lifshitz-Slyozov-Wagner (LSW) theory of particle growth driven by diffusion is applied to study beta-carotene nanoparticles with sizes of O(100 nm) formed by our block-copolymer protected Flash Nanoprecipitation process. A numerical implementation of the LSW theory that accounts for the original particle size distribution is presented. The predicted particle sizes from the numerical simulation are compared with the experimental results measured by dynamical light scattering. The results show quantitative agreement with no adjustable parameters. The addition of antisolvent results in the reduction of the ripening rate by dramatically decreasing bulk solubility.

Modelling of human disease in genetically engineered pigs provides unique possibilities in biomedical research and in studies of disease intervention. Establishment of methodologies that allow efficient gene insertion by non-viral gene carriers is an important step towards development of new disease models. In this report, we present transgenic pigs created by Sleeping Beauty DNA transposition in primary porcine fibroblasts in combination with somatic cell nuclear transfer by handmade cloning. Göttingen minipigs expressing green fluorescent protein are produced by transgenesis with DNA transposon vectors carrying the transgene driven by the human ubiquitin C promoter. These animals carry multiple copies (from 8 to 13) of the transgene and show systemic transgene expression. Transgene-expressing pigs carry both transposase-catalyzed insertions and at least one copy of randomly inserted plasmid DNA. Our findings illustrate critical issues related to DNA transposon-directed transgenesis, including coincidental plasmid insertion and relatively low Sleeping Beauty transposition activity in porcine fibroblasts, but also provide a platform for future development of porcine disease models using the Sleeping Beauty gene insertion technology.

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Structural engineering and creating atomic disorder in electrodes are promising strategies for highly efficient and rapid charge storage in advanced batteries. Herein, a nanohybrid architecture is presented with amorphous vanadium oxide conformally coated on layered V2C MXene (a‐VOx/V2C) via tunable anodic oxidation, which exhibits a high reversible capacity of 307 mAh g–1 at 50 mA g–1, decent rate capability with capacity up to 96 mAh g–1 at 2000 mA g–1, and good cycling stability as a cathode for sodium‐ion batteries. The a‐VOx layer enables reversible and fast Na+ insertion/extraction by providing sufficient vacancies and open pathways in the amorphous framework, unlike the irreversible phase transition in its crystalline counterpart, while layered V2C MXene offers abundant electron/ion transfer channels, which are joined together to boost the electrochemical performance. Notably the improved reversibility and structural superiority of the a‐VOx/V2C nanohybrid are clearly revealed by in situ Raman, in situ transmission electron microscopy, in situ synchrotron X‐ray absorption spectroscopy, and density functional theory calculations, demonstrating a reversible V–O vibration and valence oscillation between V4+ and V5+ in the disordered framework, with robust structural stability and unobstructed Na+ diffusion. This work provides a meaningful reference for the elaborate design of MXene‐based nanostructured electrodes toward advanced rechargeable batteries.

Soil salinity reduces soybean growth and yield. The recently identified GmSALT3 (Glycine max salt Tolerance-associated gene on chromosome 3) has the potential to improve soybean yields in salinized conditions. Here we evaluate the impact of GmSALT3 on soybean performance under saline or non-saline conditions. Three sets of near isogenic lines (NILs), with genetic similarity of 95.6–99.3% between each pair of NIL-T and NIL-S, were generated from a cross between two varieties 85–140 (salt-sensitive, S) and Tiefeng 8 (salt-tolerant, T) by using marker-assisted selection. Each NIL-T; 782-T, 820-T and 860-T, contained a common ~1000 kb fragment on chromosome 3 where GmSALT3 was located. We show that GmSALT3 does not contribute to an improvement in seedling emergence rate or early vigor under salt stress. However, when 12-day-old seedlings were exposed to NaCl stress, the NIL-T lines accumulated significantly less leaf Na+ compared with their corresponding NIL-S, while no significant difference of K+ concentration was observed between NIL-T and NIL-S; the magnitude of Na+ accumulation within each NIL-T set was influenced by the different genetic backgrounds. In addition, NIL-T lines accumulated less Cl- in the leaf and more in the root prior to any difference in Na+; in the field they accumulated less pod wall Cl- than the corresponding NIL-S lines. Under non-saline field conditions, no significant differences were observed for yield related traits within each pair of NIL-T and NIL-S lines, indicating there was no yield penalty for having the GmSALT3 gene. In contrast, under saline field conditions the NIL-T lines had significantly greater plant seed weight and 100-seed weight than the corresponding NIL-S lines, meaning GmSALT3 conferred a yield advantage to soybean plants in salinized fields. Our results indicated that GmSALT3 mediated regulation of both Na+ and Cl- accumulation in soybean, and contributes to improved soybean yield through maintaining a higher seed weight under saline stress.