108 research outputs found

    [N′-(3-Meth­oxy-2-oxidobenzyl­idene)nicotinohydrazidato]diphenyl­tin(IV)

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    The asymmetric unit of the title compound, [Sn(C6H5)2(C14H11N3O3)], contains two crystallographically independent mol­ecules that differ predominantly in the torsion of the phenyl rings. In both mol­ecules, the SnIV ion is in a distored trigonal-bipyramidal geometry. The Sn—O distances are in the range 2.055 (2)–2.143 (2) Å

    Connections Between Connexins, Calcium, and Cataracts in the Lens

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    There is a good deal of evidence that the lens generates an internal micro circulatory system, which brings metabolites, like glucose, and antioxidants, like ascorbate, into the lens along the extracellular spaces between cells. Calcium also ought to be carried into the lens by this system. If so, the only path for Ca2+ to get out of the lens is to move down its electrochemical gradient into fiber cells, and then move by electrodiffusion from cell to cell through gap junctions to surface cells, where Ca-ATPase activity and Na/Ca exchange can transport it back into the aqueous or vitreous humors. The purpose of the present study was to test this calcium circulation hypothesis by studying calcium homeostasis in connexin (Cx46) knockout and (Cx46 for Cx50) knockin mouse lenses, which have different degrees of gap junction coupling. To measure intracellular calcium, FURA2 was injected into fiber cells, and the gradient in calcium concentration from center to surface was mapped in each type of lens. In wild-type lenses the coupling conductance of the mature fibers was ∼0.5 S/cm2 of cell to cell contact, and the best fit to the calcium concentration data varied from 700 nM in the center to 300 nM at the surface. In the knockin lenses, the coupling conductance was ∼1.0 S/cm2 and calcium varied from ∼500 nM at the center to 300 nM at the surface. Thus, when the coupling conductance doubled, the concentration gradient halved, as predicted by the model. In knockout lenses, the coupling conductance was zero, hence the efflux path was knocked out and calcium accumulated to ∼2 μM in central fibers. Knockout lenses also had a dense central cataract that extended from the center to about half the radius. Others have previously shown that this cataract involves activation of a calcium-dependent protease, Lp82. We can now expand on this finding to provide a hypothesis on each step that leads to cataract formation: knockout of Cx46 causes loss of coupling of mature fiber cells; the efflux path for calcium is therefore blocked; calcium accumulates in the central cells; at concentrations above ∼1 μM (from the center to about half way out of a 3-wk-old lens) Lp82 is activated; Lp82 cleaves cytoplasmic proteins (crystallins) in central cells; and the cleaved proteins aggregate and scatter light

    Enhanced bioremediation of aged polycyclic aromatic hydrocarbons in soil using immobilized microbial consortia combined with strengthening remediation strategies

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    Microbial biodegradation is considered as one of the most effective strategies for the remediation of soil contaminated with polycyclic aromatic hydrocarbons (PAHs). To improve the degradation efficiency of PAHs, PAH-degrading consortia combined with strengthening remediation strategies was used in this study. The PAH biodegrading performance of seven bacterial consortia constructed by different ratios of Mycobacterium gilvum MI, Mycobacterium sp. ZL7 and Rhodococcus rhodochrous Q3 was evaluated in an aqueous system containing phenanthrene, pyrene, benzo[a]pyrene and benzo[b]fluoranthene. Bacterial consortium H6 (Q3:ZL7:MI = 1:2:2) performed a high degrading efficiency of 59% in 8 days. The H6 was subsequently screened to explore its potential ability and performance to degrade aged PAHs in soils from a coking plant and the effects of strengthening strategies on the aged PAH degradation, including the addition of glucose or sodium dodecyl benzene sulfonate (SDBS) individually or as a mixture along immobilization of the inoculant on biochar. The highest degradation efficiencies, which were 15% and 60% for low-molecular-weight (LMW) PAHs and high-molecular-weight (HMW) PAHs, respectively, were observed in the treatment using immobilized microbial consortium H6 combined with the addition of glucose and SDBS after 24 days incubation. This study provides new insights and guidance for future remediation of aged PAH contaminated soils

    Hemicellulases and auxiliary enzymes for improved conversion of lignocellulosic biomass to monosaccharides

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    <p>Abstract</p> <p>Background</p> <p>High enzyme loading is a major economic bottleneck for the commercial processing of pretreated lignocellulosic biomass to produce fermentable sugars. Optimizing the enzyme cocktail for specific types of pretreated biomass allows for a significant reduction in enzyme loading without sacrificing hydrolysis yield. This is especially important for alkaline pretreatments such as Ammonia fiber expansion (AFEX) pretreated corn stover. Hence, a diverse set of hemicellulases supplemented along with cellulases is necessary for high recovery of monosaccharides.</p> <p>Results</p> <p>The core fungal cellulases in the optimal cocktail include cellobiohydrolase I [CBH I; glycoside hydrolase (GH) family 7A], cellobiohydrolase II (CBH II; GH family 6A), endoglucanase I (EG I; GH family 7B) and β-glucosidase (βG; GH family 3). Hemicellulases tested along with the core cellulases include xylanases (LX1, GH family 10; LX2, GH family 10; LX3, GH family 10; LX4, GH family 11; LX5, GH family 10; LX6, GH family 10), β-xylosidase (LβX; GH family 52), α-arabinofuranosidase (LArb, GH family 51) and α-glucuronidase (LαGl, GH family 67) that were cloned, expressed and/or purified from different bacterial sources. Different combinations of these enzymes were tested using a high-throughput microplate based 24 h hydrolysis assay. Both family 10 (LX3) and family 11 (LX4) xylanases were found to most efficiently hydrolyze AFEX pretreated corn stover in a synergistic manner. The optimal mass ratio of xylanases (LX3 and LX4) to cellulases (CBH I, CBH II and EG I) is 25:75. LβX (0.6 mg/g glucan) is crucial to obtaining monomeric xylose (54% xylose yield), while LArb (0.6 mg/g glucan) and LαGl (0.8 mg/g glucan) can both further increase xylose yield by an additional 20%. Compared with Accellerase 1000, a purified cocktail of cellulases supplemented with accessory hemicellulases will not only increase both glucose and xylose yields but will also decrease the total enzyme loading needed for equivalent yields.</p> <p>Conclusions</p> <p>A diverse set of accessory hemicellulases was found necessary to enhance the synergistic action of cellulases hydrolysing AFEX pretreated corn stover. High glucose (around 80%) and xylose (around 70%) yields were achieved with a moderate enzyme loading (~20 mg protein/g glucan) using an in-house developed cocktail compared to commercial enzymes.</p

    Genome-wide identification and expression analysis of the MYB transcription factor in moso bamboo (Phyllostachys edulis)

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    The MYB family, one of the largest transcription factor (TF) families in the plant kingdom, plays vital roles in cell formation, morphogenesis and signal transduction, as well as responses to biotic and abiotic stresses. However, the underlying function of bamboo MYB TFs remains unclear. To gain insight into the status of these proteins, a total of 85 PeMYBs, which were further divided into 11 subgroups, were identified in moso bamboo (Phyllostachys edulis) by using a genome-wide search strategy. Gene structure analysis showed that PeMYBs were significantly different, with exon numbers varying from 4 to 13. Phylogenetic analysis indicated that PeMYBs clustered into 27 clades, of which the function of 18 clades has been predicted. In addition, almost all of the PeMYBs were differently expressed in leaves, panicles, rhizomes and shoots based on RNA-seq data. Furthermore, qRT-PCR analysis showed that 12 PeMYBs related to the biosynthesis and deposition of the secondary cell wall (SCW) were constitutively expressed, and their transcript abundance levels have changed significantly with increasing height of the bamboo shoots, for which the degree of lignification continuously increased. This result indicated that these PeMYBs might play fundamental roles in SCW thickening and bamboo shoot lignification. The present comprehensive and systematic study on the members of the MYB family provided a reference and solid foundation for further functional analysis of MYB TFs in moso bamboo

    Protecting Intestinal Microenvironment Alleviates Acute Graft-Versus-Host Disease

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    Acute gut graft-versus-host disease (aGVHD) is a leading threat to the survival of allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. Abnormal gut microbiota is correlated with poor prognosis in allo-HSCT recipients. A disrupted intestinal microenvironment exacerbates dysbiosis in GVHD patients. We hypothesized that maintaining the integrity of the intestinal barrier may protect gut microbiota and attenuate aGVHD. This hypothesis was tested in a murine aGVHD model and an in vitro intestinal epithelial culture. Millipore cytokine array was utilized to determine the expression of proinflammatory cytokines in the serum. The 16S rRNA sequencing was used to determine the abundance and diversity of gut microbiota. Combining Xuebijing injection (XBJ) with a reduced dose of cyclosporine A (CsA) is superior to CsA alone in improving the survival of aGVHD mice and delayed aGVHD progression. This regimen also reduced interleukin 6 (IL-6) and IL-12 levels in the peripheral blood. 16S rRNA analysis revealed the combination treatment protected gut microbiota in aGVHD mice by reversing the dysbiosis at the phylum, genus, and species level. It inhibited enterococcal expansion, a hallmark of GVHD progression. It inhibited enterococcal expansion, a hallmark of GVHD progression. Furthermore, Escherichia coli expansion was inhibited by this regimen. Pathology analysis revealed that the combination treatment improved the integrity of the intestinal tissue of aGVHD mice. It also reduced the intestinal permeability in aGVHD mice. Besides, XBJ ameliorated doxorubicin-induced intestinal epithelial death in CCK-8 assay. Overall, combining XBJ with CsA protected the intestinal microenvironment to prevent aGVHD. Our findings suggested that protecting the intestinal microenvironment could be a novel strategy to manage aGVHD. Combining XBJ with CsA may reduce the side effects of current aGVHD prevention regimens and improve the quality of life of allo-HSCT recipients

    Lens intracellular hydrostatic pressure is generated by the circulation of sodium and modulated by gap junction coupling

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    We recently modeled fluid flow through gap junction channels coupling the pigmented and nonpigmented layers of the ciliary body. The model suggested the channels could transport the secretion of aqueous humor, but flow would be driven by hydrostatic pressure rather than osmosis. The pressure required to drive fluid through a single layer of gap junctions might be just a few mmHg and difficult to measure. In the lens, however, there is a circulation of Na+ that may be coupled to intracellular fluid flow. Based on this hypothesis, the fluid would cross hundreds of layers of gap junctions, and this might require a large hydrostatic gradient. Therefore, we measured hydrostatic pressure as a function of distance from the center of the lens using an intracellular microelectrode-based pressure-sensing system. In wild-type mouse lenses, intracellular pressure varied from ∼330 mmHg at the center to zero at the surface. We have several knockout/knock-in mouse models with differing levels of expression of gap junction channels coupling lens fiber cells. Intracellular hydrostatic pressure in lenses from these mouse models varied inversely with the number of channels. When the lens’ circulation of Na+ was either blocked or reduced, intracellular hydrostatic pressure in central fiber cells was either eliminated or reduced proportionally. These data are consistent with our hypotheses: fluid circulates through the lens; the intracellular leg of fluid circulation is through gap junction channels and is driven by hydrostatic pressure; and the fluid flow is generated by membrane transport of sodium

    Research on the cultivation of applied innovative talents in art design under the background of new liberal arts construction based on Cocos Digital Technology

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    In today’s new era of digital technology-driven innovation, the continuous development of information technology has brought reforms and innovations to the education field, and has injected new vitality into the modernization of education in my country. The use of information technology to promote educational reforms is incorporated into education related policies. Innovation is the driving force of national development, and it is also the focus of international competition and talent training under the background of economic globalization. The construction of new liberal arts is an innovative development measure for China’s higher liberal arts education in the new era. It is the emphasis and requirement of liberal arts in the development of science and technology today. In the context of the new liberal arts, the training of art design professionals should be cross-integrated with computer science, information technology and other disciplines, combined with the development and needs of regional digital industries, breaking professional boundaries, and mastering cutting-edge technology on the premise of adhering to the core values of art and design education. At the same time, reconstruct the talent training model. This article elaborated on the development trend of digital and informatization of art design education in the talent training and discipline construction of the art design major, and the official team of Cocos Engine-Yaji Software to build the Cocos Digital Technology Industry College to create a new mode of efficient integration of production and education., To build a unique digital art talent training system, to effectively connect the talent chain and the industrial chain, to promote the industrialization of academic achievements, to cultivate application-oriented talents that meet the needs of the digital industry, and to promote the construction of a new liberal arts major in art design

    A Novel Tripartite Evolutionary Game Model for Internet Consumer Financial Regulation

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    Due to many social problems caused by Internet consumer finance, Internet consumer finance regulation has always become one of the main concerns of governments and society. Based on a novel three-dimensional mixed strategy game matrix, this paper constructs a tripartite evolutionary game model for regulators, Internet consumer financial institutions, and consumers. In this model, we establish the dynamic replication equation of the three parties above, analyze the influence of factors on the tripartite strategy selection and discuss the stability of model equilibrium points through numerical simulation. The results show that the model will get six evolutionary stable points in Internet consumer financial regulation under different conditions. Moreover, strict regulation, verification, and contract keeping are the most ideal evolutionarily stable strategies. In addition, three critical factors affect the evolution results of the three parties, namely losses to institutions caused by loose regulation and verification, punishment for loose verification under strict regulation, and losses from breaking the contract
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