A single residue mutation of 5-enoylpyruvylshikimate-3-phosphate synthase in Pseudomonas stutzeri enhances resistance to the herbicide glyphosate

A novel class II 5-enoylpyruvylshikimate-3-phosphate synthase (EPSPS) was identified from Pseudomonas stutzeri A1501 by complementation of an Escherichia coli auxotrophic aroA mutant. The single amino acid substitution of serine (Ser) for asparagine (Asn)-130 of the A1501 EPSPS enhanced resistance to 200 mM glyphosate. The mutated EPSPS had a 2.5-fold increase for IC(50) [glyphosate] value, a 2-fold increase for K (i) [glyphosate] value, but a K (m) [PEP] value similar to that of wild type. The effect of the single residue mutation on glyphosate resistance was also analyzed using a computer-based three-dimensional model.     

异色瓢虫成虫耐寒能力的季节性变化

为研究异色瓢虫Harmonia axyridis自然种群耐寒能力的季节性变化,测定了其过冷却点、体内含水量及总脂肪含量和低温存活力。结果表明：异色瓢虫成虫低温存活力呈现出明显的季节性变化,越冬前成虫的耐寒性显著强于夏季成虫和越冬后成虫。冷驯化（5℃, 5 d）可以显著提高夏季成虫的低温存活力。雌雄成虫过冷却点和体内含水量随气温的降低而降低,升高而升高。过冷却点7月份最高,分别为−7.6℃和−8.0℃;越冬中期（2008-01-15）最低,分别为−18.1℃ 和−16.9℃。雌雄成虫体内含水量9月份最高,分别为66.87%和68.01%,10月份显著降低,越冬后期（2008-02-19）最低,分别为52.94%和51.53%。越冬期间过冷却点和体内含水量显著低于其他时期。而雌雄成虫体内总脂肪含量在越冬开始就达到最高,分别为50.07%和47.93%,随后又逐渐降低,越冬期间显著高于其他时期。由此可知异色瓢虫自然种群的耐寒性呈现出明显的季节性变化,文中还就异色瓢虫自然种群耐寒性影响因素及其越冬策略进行了讨论。     

Administration of signalling molecules dictates stem cell homing for in situ regeneration

Ex vivo‐expanded stem cells have long been a cornerstone of biotherapeutics and have attracted increasing attention for treating intractable diseases and improving tissue regeneration. However, using exogenous cellular materials to develop restorative treatments for large numbers of patients has become a major concern for both economic and safety reasons. Advances in cell biological research over the past two decades have expanded the potential for using endogenous stem cells during wound healing processes, and in particular, recent insight into stem cell movement and homing has prompted regenerative research and therapy based on recruiting endogenous cells. Inspired by the natural healing process, artificial administration of specific chemokines as signals systemically or at the injury site, typically using biomaterials as vehicles, is a state‐of‐the‐art strategy that potentiates stem cell homing and recreates an anti‐inflammatory and immunomodulatory microenvironment to enhance in situ tissue regeneration. However, pharmacologically coaxing endogenous stem cells to act as therapeutics in the field of biomedicine remains in the early stages; its efficacy is limited by the lack of innovative methodologies for chemokine presentation and release. This review describes how to direct the homing of endogenous stem cells via the administration of specific signals, with a particular emphasis on targeted signalling molecules that regulate this homing process, to enhance in situ tissue regeneration. We also provide an outlook on and critical considerations for future investigations to enhance stem cell recruitment and harness the reparative potential of these recruited cells as a clinically relevant cell therapy.     

甲型肝炎病毒的提取及免疫学性质分析

目的建立甲型肝炎病毒(hepatitis A virus, HAV)的提取方法,了解和掌握HAV的免疫学性质。方法利用人胚肺二倍体细胞培养并收获HAV,用层析纯化等方法提取HAV,然后通过抗原检测、免疫电镜检查以及小鼠免疫试验对HAV的免疫学性质进行检测和分析。结果利用层析纯化等方法提取HAV,抗原回收率达84%以上,蛋白去除率达97%以上,电镜及免疫电镜检查可以观测到典型的HAV以及HAV+IgM抗原抗体免疫复合物和HAV+IgG抗原抗体免疫复合物,免疫小鼠抗体阳转率为100%。结论利用层析纯化等方法可以对HAV进行有效提取,提取的HAV具有良好的免疫反应性和免疫原性。     

The glucose‐deprivation network counteracts lapatinib‐induced toxicity in resistant ErbB2‐positive breast cancer cells

Dynamic interactions between intracellular networks regulate cellular homeostasis and responses to perturbations. Targeted therapy is aimed at perturbing oncogene addiction pathways in cancer, however, development of acquired resistance to these drugs is a significant clinical problem. A network‐based computational analysis of global gene expression data from matched sensitive and acquired drug‐resistant cells to lapatinib, an EGFR/ErbB2 inhibitor, revealed an increased expression of the glucose deprivation response network, including glucagon signaling, glucose uptake, gluconeogenesis and unfolded protein response in the resistant cells. Importantly, the glucose deprivation response markers correlated significantly with high clinical relapse rates in ErbB2‐positive breast cancer patients. Further, forcing drug‐sensitive cells into glucose deprivation rendered them more resistant to lapatinib. Using a chemical genomics bioinformatics mining of the CMAP database, we identified drugs that specifically target the glucose deprivation response networks to overcome the resistant phenotype and reduced survival of resistant cells. This study implicates the chronic activation of cellular compensatory networks in response to targeted therapy and suggests novel combinations targeting signaling and metabolic networks in tumors with acquired resistance.     

癌细胞原代培养对化疗药物敏感性的探讨

目的通过对不同抗癌药物敏感性做比较,以期寻找各自的合理化疗用药方案,从而指导不同癌症病人的化疗。方法通过肿瘤细胞体外药敏试验（即四甲基偶氮唑盐着色法,MTT）,对161例肿瘤（胃癌28例,肠癌38例,膀胱癌8例,乳腺癌33例,其他肿瘤54例）新鲜瘤组织进行表阿霉素（EADM）、氨甲蝶呤（MTX）、丝裂霉素（MMC）、长春新碱（VCR）、5-氟脲嘧啶（5-FU）、羟基喜树碱（OPT）、顺铂（DDP）、卡铂（CBP）、环磷酰胺（CTX）、足叶乙甙（VP-16）、β-揽香烯（β-elemene）11种化疗药物敏感性检测,并对其结果进行比较。结果11种抗癌药对不同的肿瘤类型耐药率不同。结论各种类型肿瘤细胞对化疗药物的选择虽有一定共性,但同种肿瘤的不同个体对同种化疗药物的抑制率差异却存有显著性。肿瘤细胞体外药物敏感性测定对肿瘤病人个体的化疗具有一定价值。     

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.     

靶向HPV16-E6的siRNA对宫颈癌CaSki细胞的抑制作用

以RNA干扰技术为手段,HPV编码的癌蛋白E6为靶标．探讨靶向HPV16-E6的siRNA对宫颈癌细胞生物学行为的影响,并试图阐明该实验的临床意义．构建靶向HPV16-E6的siRNA表达载体,应用体外转染试剂转染HPV16-E6阳性的宫颈癌CaSki细胞．以RT—PCR检测CaSki细胞中E6蛋白的mRNA的表达．借助细胞色素c测定来分析细胞凋亡相关分子的表达和活性．从而研究靶向HPV16-E6的siRNA诱导细胞凋亡的分子机制．RT．PCR检测结果表明,将靶向HPV16-E6的siRNA的表达载体瞬时转染到HPV16-E6阳性的CaSki细胞后,其所舍E6蛋白质和mRNA的表达下调;Westernblotting栓出抑凋亡蛋白Bcl．2的表达亦告下调;细胞色素C释放实验结果显示,HPV16-E6siRNA能够诱导细胞色素c从线粒体释放到细胞浆中。从而诱导细胞凋亡．靶向HPV16-E6的siRNA能够有效抑制细胞增殖并诱导细胞凋亡．靶向HPV16-E6的siRNA为研究重要致瘤蛋白HPV16-E的功能开辟了新途径,给HPV16-E6阳性肿瘤的靶向基因治疗提供新的实验依据．并探索了HPV感染及宫颈癌的新基因疗法．