血红素加氧酶介导GA对小麦糊粉层中α-淀粉酶的诱导表达

单独以赤霉素（GA）处理或与HO．1诱导物高铁血红素（Ht）和CO水溶液组合处理均导致小麦糊粉层中血红素加氧酶（H0）活性的提高,同时仪-淀粉酶基因表达和α-淀粉酶活性也明显受诱导;用HO-1专一性抑制剂锌原卟啉（ZnPPIX）预处理6h后,上述效应部分受阻断。这暗示HO可能参与GA诱导的α-淀粉酶基因表达。     

Bienzyme system for the biocatalyzed deposition of polyaniline templated by multiwalled carbon nanotubes: a biosensor design

A novel method based on covalent attachment of two enzymes, glucose oxidase (GOD) and horseradish peroxide (HRP), onto carboxylic-derived multiwalled carbon nanotubes (MWNTs) for the deposition of electroactive polyaniline (PANI) under ambient conditions is described. Ultraviolet-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and transmission electron microscopy were used to characterize the assembling of bienzyme and the morphology of PANI|MWNTs. Under the bienzyme biocatalytic condition, a head-to-tail structure of PANI templated by MWNTs was formed. The voltammetric characteristics of the resulting biosensor were investigated by cyclic voltammetry in the presence of glucose. The current response of PANI was linearly related to glucose concentration between 0.05 and 12.0mM with a correlation coefficient of 0.994. The synergistic performance of bienzyme, highly efficient polymerization, and templated deposition provide a general platform for the synthesis of nanowires and nanocircuits, the construction of bioelectronic devices, and the design of novel biosensors.     

不同风化程度钾长石表面矿物分解细菌的筛选及遗传多样性

【目的】不同风化程度钾长石表面矿物分解细菌生物多样性研究将有助于了解矿物生物风化、生物成矿和土壤形成的演化规律和机理。【方法】采用纯培养法自南平钾矿区高、中、低风化度钾长石以及矿区土壤样品中分离矿物分解细菌,通过摇瓶释硅实验比较不同菌株分解矿物能力,采用16SrDNA限制性酶切多态性分析(Amplified rDNA Restriction Analysis,ARDRA)研究了供试菌株的遗传多样性。【结果】分离筛选到35株生长良好的矿物分解细菌,与对照相比,接菌处理发酵液中有效硅增加了101～206%;所有供试菌株可分为11个OTU,分别属于5个门,6个科,7个属。多数菌株(74%)属于γ-变形杆菌纲(γ-Proteobacteria)。泛菌属(Pantoea),沙雷氏菌属(Serratia),假单胞菌属(Pseudomonas)为优势种群。【结论】南平钾矿区矿物分解细菌具有丰富的微生物种群多样性,且γ-变形杆菌纲(γ-Proteobacteria)细菌在钾长石风化过程中可能起了重要的作用。     

Precise Reconstruction of Veins and Bile Ducts in Rat Liver Transplantation

Rat orthotopic liver transplantation (ROLT) remains a technically demanding procedure, especially regarding the reconstruction of the suprahepatic vena cava (SHVC). In this study, a new microsuture technique was developed for anastomosis of the SHVC, and a special single-groove cuff and blade-cut stent were introduced. With these modified techniques, we aimed to make a precise anastomosis of the SHVC and to provide optimal cuffs and stents for the reconstruction of the veins and bile ducts. According to different microsuture techniques for the SHVC and different types of cuffs and stents, three ROLT groups were created to compare the operation times and prognoses. Sham operations were performed as controls in the fourth group. The time expenditures with each step were compared among the transplantation groups. Biochemical parameters were tested at the end of a 1-month observation period. The short- and long-term survival rates of the transplantation groups were recorded and compared. Our new microsuture technique was faster than the conventional continuous suture technique for SHVC anastomosis (P < 0.05). The use of a single-groove cuff for reconstruction of the portal vein and the infrahepatic vena cava shortened the anastomotic time (P < 0.05). The use of blade-cut stents resulted in fewer biliary complications and better survival over the short and long terms (P < 0.05). Our new microsuture technique and the single-groove cuffs proved to be a precise method for venous reconstruction which shortened the anhepatic time and the anastomotic time significantly. The blade-cut stents apparently reduced the incidence of biliary complications. In summary, with this precise microsuture technique and delicate cuffs and stents, excellent long-term survival can be achieved easily and stably for ROLT.     

Improvement of xylose utilization in Clostridium acetobutylicum via expression of the talA gene encoding transaldolase from Escherichia coli

Clostridium acetobutylicum ATCC 824 was metabolically engineered for improved xylose utilization. The gene talA, which encodes transaldolase from Escherichia coli K-12, was cloned and overexpressed in C. acetobutylicum ATCC 824. Compared with C. acetobutylicum ATCC 824 (824-WT), the transformant bearing the E. coli talA gene (824-TAL) showed improved ability on xylose utilization and solvents production using xylose as the sole carbon source. During the fermentation of xylose and glucose mixtures with three xylose/glucose ratios (approximately 1:2, 1:1 and 2:1), the rate of xylose consumption and final solvents titers of 824-TAL were all higher than those of 824-WT, despite glucose repression on xylose uptake still existing. These results suggest that the insufficiency of transaldolase in the pentose phosphate pathway (PPP) of C. acetobutylicum is one of the bottlenecks for xylose metabolism and therefore, overexpressing the gene encoding transaldolase is able to improve xylose utilization and solvent production.     

Impact of a static magnetic field on the electricity production of Shewanella-inoculated microbial fuel cells

The electricity production of Shewanella-inoculated microbial fuel cells (MFCs) under magnetic field (MF) exposure was investigated in different reactor systems. The persistency of the MF effect and the influences of MF intensity and direction on MFC performance were also studied. Application of a 100-mT static MF to the MFCs improved electricity production considerably, with an increase in the maximum voltage by 20-27% in both single- and two-chamber MFCs, while a more conspicuous improvement in the electricity generation was observed in a three-electrode cell. The MF effects were found to be immediate and reversible, and adverse effects seemed to occur when the MF was suddenly removed. The medium components analysis demonstrated that the application of MF led to an enhanced bioelectrochemical activity of Shewanella, and no significant promotion in mediator secretion was found. The improvement in the electricity production of MFCs under MF was mainly attributed to the enhanced bioelectrochemical activity, possibly through the oxidative stress mechanism. An accelerated cell growth under MF might also contribute to the enhanced substrate degradation and power generation.     

基于稳定同位素的喀斯特坡地尾巨桉水分利用特征

利用稳定性氢氧及碳同位素技术,与邻近乡土植物枫香比较,对喀斯特坡地尾巨桉水分来源与水分利用效率的季节性差异进行研究,分析喀斯特地区桉树人工林建设的干旱胁迫风险.结果表明: 浅层(0～50 cm)土壤水同位素值渐变特征明显且与近期雨水同位素值相近,而深层(50～100 cm)土壤水同位素值整体较稳定且明显区别于浅层.土壤含水量整体呈现雨季(5、9月)高于旱季(10月),且上坡高于下坡的基本特征.枫香不受旱、雨季土壤含水率差异的影响,始终以浅层土壤水为主要水源,水分利用效率持续较高.尾巨桉水分来源受不同季节、坡位土壤含水率差异的影响:雨季上坡以浅层土壤水为主,雨季下坡对深层土壤水利用比例明显增加;旱季上坡主要利用较深层水分,旱季下坡依赖浅层土壤水.桉树水分利用效率始终低于枫香,但旱季时显著升高.尾巨桉水分来源灵活多变,但干旱条件下水分利用效率显著升高,表明其并未能获得充足的水分供应,预示着生长速率及经济收益遭受负面影响,干旱致死的风险较高.     

Nuclear and nucleolar localization of 18-kDa fibroblast growth factor-2 is controlled by C-terminal signals

Members of high (22-, 22.5-, 24-, and 34-kDa) and low (18-kDa) molecular mass forms of fibroblast growth factor-2 (FGF-2) regulate cell proliferation, differentiation, and migration. FGF-2s have been previously shown to accumulate in the nucleus and nucleolus. Although high molecular weight forms of FGF-2 contain at least one nuclear localization signal (NLS) in their N-terminal extension, the 18-kDa FGF-2 does not contain a standard NLS. To determine signals controlling the nuclear and subnuclear localization of the 18-kDa FGF-2, its full-length cDNA was fused to that of green fluorescent protein (GFP). The fusion protein was primarily localized to the nucleus of COS-7 and HeLa cells and accumulated in the nucleolus. The subcellular distribution was confirmed using wild type FGF-2 and FGF-2 tagged with a FLAG epitope. A 17-amino acid sequence containing two groups of basic amino acid residues separated by eight amino acid residues directed GFP and a GFP dimer into the nucleus. We systematically mutated the basic amino acid residues in this nonclassical NLS and determined the effect on nuclear and nucleolar accumulation of 18-kDa FGF-2. Lys(119) and Arg(129) are the key amino acid residues in both nuclear and nucleolar localization, whereas Lys(128) regulates only nucleolar localization of 18-kDa FGF-2. Together, these results demonstrate that the 18-kDa FGF-2 harbors a C-terminal nonclassical bipartite NLS, a portion of which also regulates its nucleolar localization.     

树载脂蛋白CIcDNA序列及其组织表达

分离提取树（ｔｒｅｅｓｈｒｅｗ,ＴＳ）肝组织ｍＲＮＡ,以此为模板,反转录构建了ＴＳ肝组织ｃＤＮＡ文库。利用制备的兔抗ＴＳ载脂蛋白ＣＩ多抗血清为探针筛选该文库,获得两个阳性克隆。测序及序列分析表明：两个克隆均为ＴＳａｐｏＣＩｃＤＮＡ基因。大的克隆由３８０个核苷酸构成,包括２１ｂｐ、９５ｂｐ组成的５′和３′非编码区,２６４ｂｐ组成的一个完整开放阅读框架,编码８８个氨基酸的ａｐｏＣＩ前体,含２６个氨基酸构成的信号肽和６２肽的成熟蛋白。其成熟肽长度与大鼠、小鼠和狗的相应结构一致,但较人和狒狒ａｐｏＣＩ的成熟肽多５个氨基酸。并对其功能域进行了初步预测。ＲＮＡ印迹显示ＴＳａｐｏＣＩｍＲＮＡ不仅主要在肝组织表达;而且不同于人和其他哺乳类动物,亦可少量在小肠表达。上述结果为进一步研究ＴＳａｐｏＣＩ基因组结构、功能和体外表达奠定了基础。     

The role of CD4 T cell help for CD8 CTL activation

CD4 T cells play an important role in the initiation and persistence of CD8 T cells responses. In this review, we report on and evaluate the mechanisms by which CD4 T cells contribute to activation of CD8 T cells and the signal pathways of the down-streaming events after CD4 T cell help.