基于遥感和GIS的川西绿被时空变化研究

探索出了利用多时相MODIS数据分析绿被时空变化的技术方法,揭示出了川西2002—2008年间绿被的变化特征。建立了绿被提取模型。用其从2002—2008年的多期MODIS影像中提取出川西多期绿被数据。其次,利用GIS技术对2002—2008年间绿被变化,及其与温度、降雨的关系等进行了分析。研究表明:2002年绿被天数在195 d以上的区域有43.3%。终年无绿被的区域有4.3%。西北部植被生长日数短,而东南部生长日数长。2002—2008年间,春季绿被面积变幅最大,秋季最小。最大绿被面积出现在2006年的夏季,最小绿被面积出现在2005年的冬季。平均夏冬绿被面积差占区域面积46.7%。在季节上,绿被面积与温度和降雨量均在0.01的水平上呈显著正相关关系,其相关系数分别为0.82和0.84。该研究成果对植被生长潜力挖掘、农牧生产和生态建设决策等均有重要意义。     

草鱼呼肠孤病毒在CIK细胞中复制及形态发生的研究

以草鱼呼肠孤病毒（ＧＣＲＶ）感染的草鱼肾细胞系（ＣＩＫ）为模型,进行了草鱼呼肠孤病毒在细胞内的形态发生的研究。当病毒以感染复数为５￣１０ＰＦＵ／ＣＥＬＬ感染ＣＩＫ细胞时,在病毒感染细胞４ｈ以内的切片中,可观察到脱去部分外层衣壳的不完整病毒颗粒。感染细胞８ｈ,可观察到浆胞内病毒发生基质,其内含有大量的直径约５０ｎｍ的亚病毒颗粒,无外层蛋白结构。感染１２￣１６ｈ后,这些亚病毒颗粒装配上外层蛋白结构,形     

Molecular characterization of avian-like H1N1 swine influenza a viruses isolated in Eastern China, 2011

Currently, three predominant subtypes of influenza virus are prevalent in pig populations worldwide: H1N1, H3N2, and H1N2. European avian-like H1N1 viruses, which were initially detected in European pig populations in 1979, have been circulating in pigs in eastern China since 2007. In this study, six influenza A viruses were isolated from 60 swine lung samples collected from January to April 2011 in eastern China. Based on whole genome sequencing, molecular characteristics of two isolates were determined. Phylogenetic analysis showed the eight genes of the two isolates were closely related to those of the avian-like H1N1 viruses circulating in pig populations, especially similar to those found in China. Four potential glycosylation sites were observed at positions 13, 26, 198, 277 in the HA1 proteins of the two isolates. Due to the presence of a stop codon at codon 12, the isolates contained truncated PB1-F2 proteins. In this study, the isolates contained 591Q, 627E and 701N in the polymerase subunit PB2, which had been shown to be determinants of virulence and host adaptation. The isolates also had a D rather than E at position 92 of the NS1, a marker of mammalian adaptation. Both isolates contained the GPKV motif at the PDZ ligand domain of the 3′ end of the NS1, a characteristic marker of the European avian-like swine viruses since about 1999, which is distinct from those of avian, human and classical swine viruses. The M2 proteins of the isolates have the mutation (S31N), a characteristic marker of the European avian-like swine viruses since about 1987, which may confer resistance to amantadine and rimantadine antivirals. Our findings further emphasize the importance of surveillance on the genetic diversity of influenza A viruses in pigs, and raise more concerns about the occurrence of cross-species transmission events.     

马铃薯StPSKRs基因的克隆及其亚细胞定位分析

该研究采用同源克隆与PCR扩增方法,从马铃薯品种‘Desiree’中克隆植物磺肽素受体基因StPSKR1和StPSKR2的全长cDNA,并对其进行生物信息学分析及亚细胞定位分析,为深入研究StPSKR1和StPSKR2基因在马铃薯生长发育和生物胁迫中的作用提供理论依据。结果发现:(1)通过同源克隆与PCR扩增获得StPSKR1和StPSKR2的全长cDNA片段,并将其克隆到pGWB5-GFP载体;测序结果显示这2个基因编码的蛋白质与数据库给定的蛋白质序列保持一致,表明成功克隆到StPSKR1和StPSKR2基因。(2)StPSKR1位于马铃薯1号染色体上,cDNA全长3 042 bp,编码1 013个氨基酸,预测蛋白相对分子质量为112.16 kD,理论等电点6.27;StPSKR2位于7号染色体,cDNA全长3 135 bp,编码1 044个氨基酸,相对分子量为114.99 kD,理论等电点6.19。(3)生物信息学分析显示,StPSKR1和StPSKR2都属于跨膜蛋白。(4)亚细胞定位结果显示,StPSKR1和StPSKR2均定位于细胞膜上。     

Ethanol-induced neuronal apoptosis in vivo requires BAX in the developing mouse brain

A single episode of ethanol intoxication triggers widespread apoptotic neurodegeneration in the infant rat or mouse brain. The cell death process occurs over a 6-16 h period following ethanol administration, is accompanied by a robust display of caspase-3 enzyme activation, and meets ultrastructural criteria for apoptosis. Two apoptotic pathways (intrinsic and extrinsic) have been described, either of which may culminate in the activation of caspase-3. The intrinsic pathway is regulated by Bax and Bcl-XL and involves Bax-induced mitochondrial dysfunction and release of cytochrome c as antecedent events leading to caspase-3 activation. Activation of caspase-8 is a key event preceding caspase-3 activation in the extrinsic pathway. In the present study, following ethanol administration to infant mice, we found no change in activated caspase-8, which suggests that the extrinsic pathway is not involved in ethanol-induced apoptosis. We also found that ethanol triggers robust caspase-3 activation and apoptotic neurodegeneration in C57BL/6 wildtype mice, but induces neither phenomenon in homozygous Bax-deficient mice. Therefore, it appears that ethanol-induced neuroapoptosis is an intrinsic pathway-mediated phenomenon involving Bax-induced disruption of mitochondrial membranes and cytochrome c release as early events leading to caspase-3 activation.     

非磷酸化肌球蛋白在血小板衍生生长因子诱导的血管平滑肌细胞迁移中的作用

为了阐明非磷酸化肌球蛋白在平滑肌细胞迁移中的作用,研究探讨了非磷酸化肌球蛋白是否介导了血小板衍生生长因子(PDGF)诱导豚鼠脑基底动脉平滑肌细胞(GbaSM-4)的迁移。研究结果显示,20ng/ml以下剂量的PDGF可诱导GbaSM-4细胞发生迁移,此时肌球蛋白轻链(MLC20)磷酸化水平无变化。该迁移作用可被肌球蛋白特异性抑制剂blebbistatin所拮抗。应用RNA干扰技术抑制肌球蛋白轻链激酶表达,经免疫印迹检测经果显示,MLC20的磷酸化水平发生了显著下降;但对PDGF诱导的迁移作用无影响;在RNA干扰后blebbistatin也可抑制其迁移作用。体外ATP酶活性测定结果显示,blebbistatin对从平滑肌中提取的非磷酸化肌球蛋白的ATP酶活性有明显的抑制作用,其主要作用位点位于肌球蛋白头的头部S1。上述结果提示,非磷酸化的肌球蛋白参与了PDGF诱导的平滑肌细胞迁移。     

Secretory delivery of heterologous proteins in attenuated <Emphasis Type="Italic">Vibrio anguillarum</Emphasis> for potential use in vaccine design

To synthesize and secrete heterologous proteins in an attenuated Vibrio anguillarum strain for potential multivalent live vaccine development, different antigen-delivery systems based on bacterial-originated secretion signal peptides (SPs) were designed and identified in this work. Four SPs were derived from hemolysin of Escherichia coli, RTX protein of V. cholerae, hemolysin of V. anguillarum, zinc-metalloprotease of V. anguillarum, respectively, and their abilities to support secretion of green fluorescent protein (GFP) in an attenuated V. anguillarum strain MVAV6203 were assayed. Immunodetection of GFP showed that the capability of the tested signal leaders to direct secretion of GFP varied greatly. Although all the four signal peptide-fused GFPs could be expressed correctly and trapped intracellularly in recombinant strains, only the EmpA signal peptide could confer efficient secretion to GFP. For the investigation of its potential application in live bacteria carrier vaccines, a heterologous protein EseB of Edwardsiella tarda was fused to the SP(empA) antigen-delivery system and introduced into the strain MVAV6203. Further analysis of EseB demonstrated that the constructed SP(empA) antigen-delivery system could be used to secrete foreign protein in attenuated V. anguillarum and be available for carrier vaccines development.     

Alpha-melanocyte stimulating hormone protects retinal pigment epithelium cells from oxidative stress through activation of melanocortin 1 receptor–Akt–mTOR signaling

Patients with age related macular degeneration (AMD) will develop vision loss in the center of the visual field. Reactive oxygen species (ROS)-mediated retinal pigment epithelium (RPE) cell apoptosis is an important contributor of AMD. In this study, we explored the pro-survival effect of α-melanocyte stimulating hormone (α-MSH) on oxidative stressed RPE cells. We found that α-MSH receptor melanocortin 1 receptor (MC1R) was functionally expressed in primary and transformed RPE cells. RPE cells were response to α-MSH stimulation. α-MSH activated Akt/mammalian target of rapamycin (mTOR) and Erk1/2 signalings in RPE cells, which were inhibited by MC1R siRNA knockdown. α-MSH protected RPE cells from hydrogen peroxide (H₂O₂)-induced apoptosis, an effect that was almost abolished when MC1R was depleted by siRNA. α-MSH-mediated S6K1 activation and pro-survival effect against H₂O₂ was inhibited by Akt inhibitors (perifosine, MK-2206 and LY294002). Further, mTOR inhibition by rapamycin, or by mTOR siRNA knockdown, diminished α-MSH’s pro-survival effect in RPE cells. Thus, Akt and its downstream mTOR signaling mediates α-MSH-induced survival in RPE cells. In summary, we have identified a new α-MSH–MC1R physiologic pathway that reduces H₂O₂-induced RPE cell damage, and might minimize the risk of developing AMD.