Analysis of trehalose-6-phosphate synthase (TPS) gene family suggests the formation of TPS complexes in rice

Trehalose-6-phosphate (T6P), an intermediate in the trehalose biosynthesis pathway, is emerging as an important regulator of plant metabolism and development. T6P levels are potentially modulated by a group of trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP) homologues. In this study, we have isolated 11 TPS genes encoding proteins with both TPS and TPP domains, from rice. Functional complement assays performed in yeast tps1 and tps2 mutants, revealed that only OsTPS1 encodes an active TPS enzyme and no OsTPS protein possesses TPP activity. By using a yeast two-hybrid analysis, a complicated interaction network occurred among OsTPS proteins, and the TPS domain might be essential for this interaction to occur. The interaction between OsTPS1 and OsTPS8 in vivo was confirmed by bimolecular fluorescence complementation and coimmunoprecipitation assays. Furthermore, our gel filtration assay showed that there may exist two forms of OsTPS1 (OsTPS1a and OsTPS1b) with different elution profiles in rice. OsTPS1b was particularly cofractionated with OsTPS5 and OsTPS8 in the 360 kDa complex, while OsTPS1a was predominantly incorporated into the complexes larger than 360 kDa. Collectively, these results suggest that OsTPS family members may form trehalose-6-phosphate synthase complexes and therefore potentially modify T6P levels to regulate plant development.     

新生大鼠辣椒素处理后脊髓内阿片受体的变化

本实验用受体放射自显影方法,研究了新生大鼠辣椒素皮下注射,成年后脊髓内３Ｈ－埃托菲（３Ｈ－ｅｔｏｒｐｈｉｎｅ）结合位点数的变化。发现新生鼠辣椒素处理可以引起脊髓后角浅层及中央管周围’Ｈ－ｅｔｏｒｐｈｉｎｅ结合位点明显减,其中Ⅰ、Ⅱ层自显影银粒数减少３６％左右。Ⅲ层减少２０％,中央管周围减少１１％。而前角及背外测束３Ｈ－ｅｔｏｒｐｈｉｎｅ结合位点数无显著性差异。结果表明脊髓内初级感觉传入细纤维上有阿片受体分布。本研究为探明阿片类物质在脊髓水平的痛觉调控机制提供一定的形态学依据。     

The plant glycosyltransferase clone collection for functional genomics

The glycosyltransferases (GTs) are an important and functionally diverse family of enzymes involved in glycan and glycoside biosynthesis. Plants have evolved large families of GTs which undertake the array of glycosylation reactions that occur during plant development and growth. Based on the Carbohydrate‐Active enZymes (CAZy) database, the genome of the reference plant Arabidopsis thaliana codes for over 450 GTs, while the rice genome (Oryza sativa) contains over 600 members. Collectively, GTs from these reference plants can be classified into over 40 distinct GT families. Although these enzymes are involved in many important plant specific processes such as cell‐wall and secondary metabolite biosynthesis, few have been functionally characterized. We have sought to develop a plant GTs clone resource that will enable functional genomic approaches to be undertaken by the plant research community. In total, 403 (88%) of CAZy defined Arabidopsis GTs have been cloned, while 96 (15%) of the GTs coded by rice have been cloned. The collection resulted in the update of a number of Arabidopsis GT gene models. The clones represent full‐length coding sequences without termination codons and are Gateway^® compatible. To demonstrate the utility of this JBEI GT Collection, a set of efficient particle bombardment plasmids (pBullet) was also constructed with markers for the endomembrane. The utility of the pBullet collection was demonstrated by localizing all members of the Arabidopsis GT14 family to the Golgi apparatus or the endoplasmic reticulum (ER). Updates to these resources are available at the JBEI GT Collection website http://www.addgene.org/ .     

华广虻肠道溶纤活性蛋白的纯化和性质(英文)

经过 75 %饱和度硫酸铵沉淀、SephadexG 75凝胶过滤层析、Lys Sepharose 4B亲和层析和电泳制备洗脱 ,从华广虻 (TabanusamaenusWalker)腹部组织匀浆液中分离纯化出分子量约为 6 7KD的溶纤活性蛋白TAFP。经纤维蛋白平板测定表明 ,TAFP不仅具有纤溶酶作用 ,还具有激活纤溶酶原的作用 ;通过三肽生色底物测定发现 ,TAFP能分解纤溶酶原激活剂的生色底物—ChromozymUK及S 2 2 88。还能水解胰蛋白酶专一底物Bz Phe Val Arg NA及CBZ Gly Pro Arg NA ,表明TAFP具有类胰蛋白酶活性 ,专一水解精氨酸形成的酰胺键 (或肽键 )。TAFP无胰凝乳蛋白酶活性     

Change in microbial communities in acetate- and glucose-fed microbial fuel cells in the presence of light

Power densities produced by microbial fuel cells (MFCs) in natural systems are changed by exposure to light through the enrichment of photosynthetic microorganisms. When MFCs with brush anodes were exposed to light (4000 lx), power densities increased by 8–10% for glucose-fed reactors, and 34% for acetate-fed reactors. Denaturing gradient gel electrophoresis (DGGE) profiles based on the 16S rRNA gene showed that exposure to high light levels changed the microbial communities on the anodes. Based on 16S rRNA gene clone libraries of light-exposed systems the anode communities using glucose were also significantly different than those fed acetate. Dominant bacteria that are known exoelectrogens were identified in the anode biofilm, including a purple nonsulfur (PNS) photosynthetic bacterium, Rhodopseudomonas palustris, and a dissimilatory iron-reducing bacterium, Geobacter sulfurreducens. Pure culture tests confirmed that PNS photosynthetic bacteria increased power production when exposed to high light intensities (4000 lx). These results demonstrate that power production and community composition are affected by light conditions as well as electron donors in single-chamber air-cathode MFCs.     

局灶性脑缺血再灌损伤时神经细胞内Ca~(2+)时空动态变化的实验研究

本文用插线法制作局灶性脑缺血／再灌损伤模型,利用激光共聚焦扫描显微镜观察活体脑片细胞内Ｃａ２＋的分布及动态变化,结果表明：（１）缺血／再灌时间不同,梗塞面积不同,缺血４小时梗塞面积占同侧半球的１６．３％,缺血４小时再灌２０小时梗塞面积增加到２５．９％,缺血２４小时梗塞面积占同侧半球的６０．４％。（２）本文首次观察到在缺血４小时纹状体区域的Ｃａ２＋变化明显高于皮层,并且再灌后皮层及纹状体区域Ｃａ２＋的含量明显增加     

外源α-萘乙酸对花期干旱大豆碳代谢的影响

以耐旱性大豆品种晋豆21和干旱敏感性大豆品种徐豆22为试验材料,通过盆栽试验,研究α-萘乙酸(NAA)对花期干旱大豆碳代谢的影响.结果表明: 干旱胁迫下,与徐豆22相比,晋豆21净光合速率(P_n)下降幅度较小,光呼吸速率(P_r)和叶片可溶性糖含量增加幅度较小,而叶片蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)(合成方向)活性、根系蔗糖含量增加幅度较大.NAA处理提高了干旱胁迫下P_n,并降低了P_r,进而明显缓解了干旱胁迫对大豆植株的生长抑制;降低了叶片淀粉分解酶、酸性转化酶(AI)和SS(分解方向)活性,从而抑制了干旱胁迫诱导的可溶性糖积累;NAA处理也能增加干旱胁迫下叶片SPS、SS(合成方向)活性、根系蔗糖含量、根冠比,表明NAA处理促进了叶片中蔗糖向根系的转运.总之,在干旱胁迫下,外源NAA能够通过调控碳代谢增强大豆植株对干旱胁迫的耐受性.     

深黄被孢霉△^6—脂肪酸脱氢酶基因在转基因烟草中的表达

γ—亚麻酸(GLA)是人体和动物饮食中具有营养作用的重要的多烯不饱和脂肪酸,在大多数油料作物种子中不含有GLA,而只含有其前体物亚油酸,只有少数油料植物种子中含有GLA,如夜来香(Oenothera spp),琉璃苣(Borago officinalis)等。△^6—脂肪酸脱氢酶可将亚油酸转化为γ—亚麻酸,为了能够在传统的油料作物种子中产生GLA,我们将从深黄被孢霉中克隆的△^6—脂肪酸脱氢酶基因,与植物表达载体pGA643连接,构建了重组质粒pGAM—ICL6,将其通过农杆菌介导法,导入模式植物烟草中。经PCR和Southern杂交分析表明该基因已导入并整合到烟草的基因组中,Northern杂交结果表明该基因在转基因烟草的mRNA水平上获得表达。对转基因植株进行脂肪酸分析,结果显示,GLA和十八碳四烯酸(OTA)分别占总脂肪酸含量的19．7％和3．5％。     

含铬重组液激活部分缺失金属原子簇的钼铁蛋白的研究

棕色固氮菌（Ａｚｏｔｏｂａｃｔｅｒ ｖｉｎｅｌａｎｄｉｉ）固氮酶钼铁蛋白经邻菲口罗啉和Ｏ２ 处理后,变为部分缺失ＦｅＭｏｃｏ 和Ｐ－ｃｌｕｓｔｅｒ的失活蛋白。与由Ｋ２ＣｒＯ４、高柠檬酸铁、Ｎａ２Ｓ和二硫苏糖醇组成的重组液保温后,处理蛋白对乙炔和质子还原的活性都得以显著恢复;然而,它的吸收光谱和圆二色谱虽有明显恢复,但仍与还原钼铁蛋白有所不同。这表明,激活蛋白中也许存在功能与钼铁蛋白相似,而结构则有所差异的含铬（ＣｒＦｅ）蛋白