Microtubule dynamics is required for root elongation growth under osmotic stress in Arabidopsis

Osmotic stress caused by drought and soil salinity is one of the factors that affect plant root system growth and development. Previous studies have shown that microtubule plays a critical role in plant roots response to osmotic stress, however, the underlying mechanism remains unclear. In the present study, the microtubule orientations in Arabidopsis roots growing under osmotic stress were determined using confocal fluorescence microscopy. The results showed that osmotic stress could significantly inhibit primary root elongation in Arabidopsis, and pharmacological tests confirmed that microtubules were involved in Arabidopsis roots response to osmotic stress. In vivo visualization of microtubule structures with the microtubule-binding domain–green fluorescent protein (GFP) reporter revealed altered microtubule orientation in rhizodermal cells under osmotic stress. These results above indicated that osmotic stress could inhibit the elongation growth of Arabidopsis primary root, and the inhibition effects might result from the changes in microtubule orientation.     

Nonvirus encoded proteins could be embedded into Bombyx mori cypovirus polyhedra

To explore whether the nonvirus encoded protein could be embedded into Bombyx mori cypovirus (BmCPV) polyhedra. The stable transformants of BmN cells expressing a polyhedrin (Polh) gene of BmCPV were constructed by transfection with a non-transposon derived vector containing a polh gene. The polyhedra were purified from the midguts of BmCPV-infected silkworms and the transformed BmN cells, respectively. The proteins embedded into polyhedra were determined by mass spectrometry analysis. Host derived proteins were detected in the purified polyhedra. Analysis of structure and hydrophilicity of embedded proteins indicated that the hydrophilic proteins, in structure, were similar to the left-handed structure of polyhedrin or the N-terminal domain of BmCPV structural protein VP3, which were easily embedded into the BmCPV polyhedra. The lysate of polyhedra purified from the infected transformation of BmN cells with modified B. mori baculovirus BmPAK6 could infect BmN cells, indicating that B. mori baculovirus could be embedded into BmCPV polyhedra. Both the purified polyhedra and its lysate could be coloured by X-gal, indicating that the β-galactosidase expressed by BmPAK6 could be incorporated into BmCPV polyhedra. These results suggested that some heterologous proteins and baculovirus could be embedded into polyhedra in an unknown manner.     

Conservation and function of Dazl in promoting the meiosis of goat male germline stem cells

Dazl (deleted in azoospermia-like) is a conserved gene in mammalian meiosis, which encodes RNA binding protein required for spermatocyte meiosis. Up to date, the expression and function of Dazl in the goat testis are unknown. The objectives of this study were to investigate the expression pattern of Dazl in dairy goat testis and their function in male germline stem cells (mGSCs). The results first revealed that the expression level of Dazl in adult testes was significantly higher than younger and immature goats, and azoospermia and male intersex testis. The dairy goat Dazl is highly conserved analysed by several online and bioinformatics software, respectively. Over-expression of Dazl promoted the expression of meiosis-related genes in dairy goat mGSCs. The expression of Stra8 was up-regulated by over-expression of Dazl analysed by Luciferase reporter assay. Taken together, results suggest the Dazl plays an important role in dairy goat spermatogenesis and that over-expression of Dazl may promote Stra8 expression in dairy goat mGSCs.     

Simultaneous enhanced catalytic activity and thermostability of a 1,3-1,4-β-glucanase from Bacillus amyloliqueformis by chemical modification of lysine residues

The thermostablility and enzymatic activity of 1,3-1,4-β-glucanase (BglA) from Bacillus amyloliquefaciens was improved by modifying five (out of 12) ε-amino groups in lysine residues with nitrous acid. The optimal modification condition for BglA was determined as 30 mM nitrous acid at, 40 °C for 30 min. The optimally-modified BglA had higher specific activity and T ₅₀ value, which were 3,370 U/mg and 70 °C, respectively. Its half-life values at 50 and 60 °C were extended and reached 58.5 and 49.5 min, respectively. Circular dichroism analysis showed that the secondary structures in modified BglA were almost the same with that of wild-type BglA. Thus, modification of lysine residues can simultaneously improve the activity and thermostability of β-glucanase which are ideal targets for further protein engineering.     

RNAi干扰Ska2对H1299细胞增殖、迁移及侵袭能力的影响

Ska2（spindle and kinetochore associated complex subunit2）,又称FAM33A（family with sequence similarity33,member A）,是新近发现的一个与细胞周期调控和肿瘤发生发展紧密相关的基瓯且与该团队前期发现的新基NPRR11（proline rich 11）共享一个双向启动子。但是,Ska2在肺癌中的具体作用和分子机制仍不清楚。该研究选用肺癌细胞系H1299,采用RNAi技术构建Ska2基因沉默的稳定细胞株,并进行了细胞表型和潜在分子机制分析。RT-PCR和Western blot结果表明,Ska2在mRNA和蛋白质水平上的表达均被有效抑制。细胞增殖、细胞迁移和侵袭实验结果表明,与对照细胞相比,Ska2基因沉默稳定细胞株的细胞增殖能力、细胞迁移和侵袭能力均显著降低。此外,Ska2基因被沉默后,CCNA1基因的表达显著下调。该研究的结果提示,Ska2与其对侧基因PRR11的功能高度相关,可能与PRR11共同参与肺癌细胞增殖、迁移和侵袭行为的调节。     

Comparison of three common DNA concentration measurement methods

Accurate measurement of DNA concentration is important for DNA-based biological applications. DNA concentration is usually determined by the ultraviolet (UV) absorption, fluorescence staining, and diphenylamine reaction methods. However, the best method for quality assurance of measurements is unknown. Here, we comprehensively compared these methods using different types of samples. We found that all three methods accurately determined the concentrations of high-purity DNA solutions. After digestion of DNA samples, concentration measurements revealed that the PicoGreen dye method was very sensitive to the degradation of DNA. The three methods displayed different anti-jamming ability when contaminants such as transfer RNA (tRNA), protein, and organic chemicals were included in DNA solutions. The diphenylamine reaction method gave the highest accuracy, with an average error of approximately 10% between measured and true values. The PicoGreen dye method was influenced by tRNA and protein, and the UV absorption method was susceptible to all kinds of impurities. Overall, the diphenylamine reaction method gave the most accurate results when DNA was mixed with contaminants, the PicoGreen dye method was most suitable for degraded DNA samples or DNA extracted from processed products, and the UV absorbance method was best for evaluating the impurities in DNA solutions.     

选择性环氧合酶-2抑制剂联合奥曲肽诱导人胃癌细胞的凋亡

目的探讨选择性环氧合酶-2抑制剂NS-398与奥曲肽联合应用对人胃癌细胞株BGC-823生长、凋亡的影响。方法体外培养BGC-823细胞,分别用NS-398(100μmol/L)与奥曲肽(1μmol/L)单独及联合处理不同时间后,倒置显微镜观察细胞形态学变化;观察生长曲线的变化;流式细胞仪检测细胞凋亡率;实时定量(Real-time)PCR检测COX-2mRNA的表达;Western blot法检测Caspase-3蛋白表达。结果倒置显微镜下,对照组BGC-823细胞生长良好,药物处理后,细胞变小、变圆,悬浮,联合组细胞形态学改变显著强于单纯用药组;药物作用后,细胞生长受抑制,出现负增长,联合组作用明显强于单纯用药组;流式细胞仪检测表明联合用药组诱导BGC-823细胞的凋亡率明显高于单一用药组和对照组(P0.01);各处理组均使BGC-823细胞COX-2mRNA表达下调(P0.05);药物处理后细胞Caspase-3蛋白表达明显增加。结论 NS-398、奥曲肽联合可协同抑制BGC-823细胞生长、增殖,其机制可能与下调COX-2mRNA表达、诱导肿瘤细胞凋亡相关。     

A Two-Stage Association Study Suggests BRAP as a Susceptibility Gene for Schizophrenia

Schizophrenia (SZ) is a neurodevelopmental disorder in which altered immune function typically plays an important role in mediating the effect of environmental insults and regulation of inflammation. The breast cancer suppressor protein associated protein (BRAP) is suggested to exert vital effects in neurodevelopment by modulating the mitogen-activated protein kinase cascade and inflammation signaling. To explore the possible role of BRAP in SZ, we conducted a two-stage study to examine the association of BRAP polymorphisms with SZ in the Han Chinese population. In stage one, we screened SNPs in BRAP from our GWAS data, which detected three associated SNPs, with rs3782886 being the most significant one (P  =  2.31E-6, OR  =  0.67). In stage two, we validated these three SNPs in an independently collected population including 1957 patients and 1509 controls, supporting the association of rs3782886 with SZ (P  =  1.43E-6, OR  =  0.73). Furthermore, cis-eQTL analysis indicates that rs3782886 genotypes are associated with mRNA levels of aldehyde dehydrogenase 2 family (ALDH2) (P  =  0.0039) and myosin regulatory light chain 2 (MYL2) (P < 1.0E-4). Our data suggest that the BRAP gene may confer vulnerability for SZ in Han Chinese population, adding further evidence for the involvement of developmental and/or neuroinflammatory cascades in the illness.     

Hybrid Heterojunction and Solid‐State Photoelectrochemical Solar Cells

A hybrid heterojunction and solid‐state photoelectrochemical solar cell based on graphene woven fabrics (GWFs) and silicon is designed and fabricated. The GWFs are transferred onto n‐Si to form a Schottky junction with an embedded polyvinyl alcohol based solid electrolyte. In the hybrid solar cell, solid electrolyte serves three purposes simutaneously; it is an anti‐reflection layer, a chemical modification carrier, and a photoelectrochemical channel. The open‐circuit voltage, short‐circuit current density, and fill factor are all significantly improved, achieving an impressive power conversion efficiency of 11%. Solar cell models are constructed to confirm the hybrid working mechanism, with the heterojunction junction and photoelectrochemical effect functioning synergistically.