大豆花叶病毒CP基因原核表达与抗血清制备

根据已报道的大豆花叶病毒(SMV)序列设计引物,扩增SMV的外壳蛋白(CP)基因,序列同源性分析结果表明,与目前已报道的SMV不同分离物CP基因核苷酸序列同源性为85.0%～96.8%,相应推测的氨基酸序列同源性为87.9%～98.9%.将CP基因插入原核表达载体pSBET后在大肠杆菌BL21(DE3)Plys S中诱导表达.通过12%SDS-PAGE和5%～20%梯度SDS-PAGE两次制备电泳纯化诱导产物,免疫家兔获得抗CP血清,Western blot分析对CP具有高度特异性.硫酸铵沉淀法与Protein A-Red Sepharose 亲和层析相结合提取IgG,获得效价达1∶ 3 800的一抗,可用于田间SMV病样检测.     

小黑杨花药培养植株转化胆碱氧化酶基因提高耐盐性

以小黑杨（Populus simonii×p．nigra）花药培养植株无菌苗叶片为外植体,通过根癌农杆菌（Agrobacterium tumefaciens）介导法将胆碱氧化酶基因（codA）导入小黑杨中,共获得4株转化株系,PCR扩增和Southern杂交检测结果全部呈阳性,表明codA基因已整合到小黑杨花药培养植株基因组中。荧光定量RT-PCR检测证明,codA基因在小黑杨花药培养植株中获得表达。耐盐实验结果显示,各转基因株系在0．6％的NaCl浓度下能够生长,而非转基因对照小黑杨受盐害严重,说明codA基因的导入提高了转基因植株的耐盐性。     

湖南石门、冷水江、浏阳3个矿区的苎麻重金属含量及累积特征

对湖南省石门、冷水江、浏阳3个矿区土壤和苎麻体内重金属进行测定和分析。结果表明,石门雄黄矿区As污染严重,伴随Cd、Sb污染和轻微的Pb污染;冷水江锑矿区Sb为主要污染物,伴随Cd、As、Pb污染;浏阳七宝山矿区Cd污染严重,伴随Pb、Zn、Cu污染。15个采样点的苎麻群落生长繁茂,Sb和As在苎麻不同部位间的分布次序为叶片中含量最高,根茎中次之,其余重金属在部位间分布没有规律。所有采样点苎麻地上部的Cd含量比一般植物的Cd含量大2-10倍,As含量大9.9-147.5倍,Sb含量大1.2-338.4倍;Cd富集系数和转移系数最高值为2.07和3;As富集系数和转移系数最高值为1.04和12.42,Sb富集系数和转移系数最高值为1.91和9.04。3个矿区苎麻地上部生物量分别为3.47,14.3,15.7 t/hm²,地上部Cd、Pb、As、Sb、Zn和Cu的累积量分别高达0.11、1.17、0.72、7.97、6.71,1.69 kg/hm²,兼具一定的经济价值和观赏性,适合用作矿区重金属污染土壤的环境治理和修复。     

重庆石灰岩植被的排序及其结果解释

重庆石灰岩植被的排序及其结果解释杜道林,刘玉成（西南师范大学生物系,重庆,６３０７１５）ＯＲＤＩＡＴＩＯＮＡＮＤＥＮＶＩＲＯＮＭＥＮＴＡＬＩＮＴＥＲＰＲＥＴＡＴＩＯＮＯＦＴＨＥＣＡＬＣＡＲＥＯＵＳＶＥＧＥＴＡＴＩＯＮＩＮＣＨＯＮＧＱＩＮＧ￥ＤｕＤａｏ...     

重庆的珍稀濒危植物

按１９９１年版的《中国植物红皮书－稀有濒危植物》（第一册）,不完全统计,重庆约有全国第一批珍稀濒危植物５２种及变种（含区域不详２种）,占湖北及其附近地区第一批珍稀濒危植物种的８１．３％,华中区的３３．３％,全国的１３．４％,是全国平均水平的１５．７倍。按不同的分类标准,这些珍稀濒危植物中有蕨类植物３种,裸子植物１４种,被子植物３５种;国家一级重点保护植物５种,二级保级植物２３种,三级保护植物２４种     

木材腐朽菌在森林生态系统中的功能

木材腐朽菌是森林生态系统的重要组成部分,在森林生态系统中起着极为重要的降解还原作用,主要包括担子菌门非褶菌目、子囊菌门盘菌纲和半知菌类的部分真菌,能全部或部分降解木材中的木质素、纤维素和半纤维素,其降解机制有3种：白色腐朽、褐色腐朽和软腐朽．木材腐朽菌与生态系统中其它生物关系密切,为很多昆虫、鸟类提供营养,有些昆虫也能使木腐菌得到传播．保护木材腐朽菌的生物多样性是保护森林生态系统、维护生态系统健康的重要因素．     

磁性纳米颗粒介导分离技术筛选土壤中多氯联苯降解菌及其降解特性

【背景】磁性纳米颗粒介导分离(magnetic nanoparticle-mediated isolation, MMI)技术是近年来发展起来的一种无须底物标记就能从复杂菌群中分离活性功能微生物的方法,目前尚无研究报道该技术应用于难降解污染物3,3′,4,4′-四氯联苯(3,3′,4,4′-tetrachlorobiphenyl, PCB77)。【目的】从土壤中筛选PCB77活性降解菌并研究其污染物降解特性。【方法】利用磁性纳米颗粒(magnetic nanoparticles, MNPs)富集原位活性PCB77降解菌群,通过高通量测序分析细菌群落变化,经平板筛选得到PCB77降解菌,并研究其对多氯联苯和多溴联苯醚的降解特性。【结果】基于MMI技术获取的富集培养液能够高效地转化PCB77,与对照组相比底物降解效率从6%提升至79.3%,同时该富集培养液中细菌物种多样性显著降低,群落组成发生明显变化。从对照组和MMI处理组中分别筛选到PCB77降解菌红球菌CT2和类芽孢杆菌MT2,发现红球菌为对照组中唯一的优势物种,而MMI处理组的优势物种由红球菌和类芽孢杆菌共同组成。菌株MT2对PCB...     

Activity coefficients and thermodynamic parameters for RbCl/CsCl + amide (acetamide, propanamide, and n-butanamide) + water system at 298.15 K

Electromotive force (emf) of the chemical cell without liquid-junction K-ISE | RbCl/CsCl ( m(E)) | ISE-Cl and K-ISE | RbCl/CsCl (m(E)), amide (m(N)) | ISE-Cl, have been measured at 298.15 K, where m(E)=(0.005 to 0.5) mol kg(-1) and m(N)= (0.05 to 3.0) mol kg(-1). The activity coefficients of RbCl/CsCl in amide (acetamide, propanamide, and n-butanamide) + water mixture can be obtained from these electromotive force data and in the mean time the Gibbs free energy interaction parameters of RbCl/CsCl + amide pair in water, g(EN), as well as the salt constant, k(S), can be evaluated. The results show that both g(EN)>0, k(S)>0 at 298.15 K, and all the activity coefficients of electrolyte in amide + water mixture increase with increasing the m(N), but it is a little complicated for the dependence of activity coefficients on m(E). These thermodynamic parameters were discussed in terms of a model of the structural interaction and electrostatic interaction and the dependence of them on the number of carbon atoms in amide as well as the radius of metal ions were interpreted by the group additivity principle.     

BMP4 signaling is involved in the generation of inner ear sensory epithelia

Background  

The robust expression of BMP4 in the incipient sensory organs of the inner ear suggests possible roles for this signaling protein during induction and development of auditory and vestibular sensory epithelia. Homozygous BMP4-/- animals die before the inner ear's sensory organs develop, which precludes determining the role of BMP4 in these organs with simple gene knockout experiments.     

Matrix GLA protein stimulates VEGF expression through increased transforming growth factor-beta1 activity in endothelial cells

Matrix GLA protein (MGP) is expressed in endothelial cells (EC), and MGP deficiency results in developmental defects suggesting involvement in EC function. To determine the role of MGP in EC, we cultured bovine aortic EC with increasing concentrations of human MGP (hMGP) for 24 h. The results showed increased proliferation, migration, tube formation, and increased release of vascular endothelial growth factor-A (VEGF-A) and basic fibroblast growth factor (bFGF). HMGP, added endogenously or transiently expressed, increased VEGF gene expression dose-dependently as determined by real-time PCR. To determine the mechanism by which hMGP increased VEGF expression, we studied the effect of MGP on the activity of transforming growth factor (TGF)-beta1 compared with that of bone morphogenetic protein (BMP)-2 using transfection assays with TGF-beta- and BMP-response element reporter genes. Our results showed a strong enhancement of TGF-beta1 activity by hMGP, which was paralleled by increased VEGF expression. BMP-2 activity, on the other hand, was inhibited by hMGP. Neutralizing antibodies to TGF-beta blocked the effect of MGP on VEGF expression. The enhanced TGF-beta1 activity specifically activated the Smad1/5 pathway indicating that the TGF-beta receptor activin-like kinase 1 (ALK1) had been stimulated. It occurred without changes in expression of TGF-beta1 or ALK1 and was mimicked by transfection of constitutively active ALK1, which increased VEGF expression. Expression of VEGF and MGP was induced by TGF-beta1, but the induction of MGP preceded that of VEGF, consistent with a promoting effect on VEGF expression. Together, the results suggest that MGP plays a role in EC function, altering the response to TGF-beta superfamily growth factors.