利用花青素可视化跟踪表达系统快速筛选表达Cry1Ab/c基因的转基因玉米

以草甘膦抗性基因Epsps为标记基因, 在原核Kan^r基因两侧引入Cre(环化重组酶)基因识别的Lox-P位点, 同时以编码花青素合成转录因子的Bi和Cl基因为可视化选择报告基因, 构建了Bt杀虫蛋白基因Cry1Ab/c的可视化跟踪表达载体pBAC9017。用PDS1000/He基因枪转化玉米(Zea mays)自交系501的幼胚和胚性愈伤组织, 获得147个草甘膦抗性的玉米再生植株。其中106棵植株获得了结实种子, 16棵植株的结实种子有紫红色花青素基因的表达。经PCR检测表明, 外源Cry1Ab/c基因已经整合到玉米的基因组中。转基因植株种子蛋白粗提物用BT-Cry1Ab/1Ac金标免疫检测试纸条和ELISA检测, 结果表明, Cry1Ab/c在部分转基因植株后代中表达。     

阳离子脂质体在转基因畜禽中的应用

脂质体是由可生物降解的磷脂组成的双分子层结构,与生物膜有较大的相似性和组织相容性.阳离子脂质体作为一种新型的基因转移载体,以其生产简便、毒性低、无感染危险等优点在转基因领域越来越受到研究人员的青睐.随着转基因动物研究的不断深入,阳离子脂质体更是成为当今各种转基因方法中首选的非病毒类外源基因载体,在保护外源基因和提高其转染效率方面都发挥着重要作用.就阳离子脂质体的结构形式、介导基因转移的机制及其目前在转基因畜禽领域中的研究进展做一综述.     

免疫捕获PCR法快速检测金黄色葡萄球菌

旨在建立一种快速检测金黄色葡萄球菌(Staphylococcus aureus,SA)免疫捕获PCR技术,并探讨其灵敏度和特异性。SA特异性抗体包被PCR管以富集待测样品中目标菌,之后在同一PCR管里直接进行免疫捕获PCR,并和直接PCR比较。免疫捕获PCR法可特异性检测2株SA菌株,而无法检测到其它8种常见食源性致病菌,说明该方法对SA具有良好的特异性;该方法对纯菌液而言,检测灵敏度可达到2.35×102CFU/mL,是直接PCR的100倍;对5种食品模拟带菌检测发现,无需增菌培养,其灵敏度可达到2.35×103-2.35×104CFU/mL,是直接PCR的10-100倍。免疫捕获PCR法集免疫学与分子生物学检测技术于一体,具有高特异性、高灵敏度、检测快速、易于操作、成本低廉等诸多优点,是一种适合基层实验室使用的检测技术。     

The Structure, Function, and Regulation of Mycobacterium FtsZ

FtsZ is a widely distributed major cytoskeletal protein involved in the archaea and bacteria cell division. It is the most critical component in the division machinery and similar to tubulin in structure and function. Four major roles of FtsZ have been characterized: cell elongation, GTPase, cell division, and bacterial cytoskeleton. FtsZ subunits can be assembled into protofilaments. Mycobacteria consist of a large family of medical and environmental important bacteria, such as M. leprae, M. tuberculosis, the pathogen of leprosy, and tuberculosis. Structure, function, and regulation of mycobacteria FtsZ are summarized here, together with the implication of FtsZ as potential novel drug target for anti-tuberculosis therapeutics.     

The p35/CDK5 signaling is regulated by p75NTR in neuronal apoptosis after intracerebral hemorrhage

The p75 neurotrophin receptor (p75NTR), a member of tumor necrosis factor receptor superfamily, involves in neuronal apoptosis after intracerebral hemorrhage (ICH). It has been previously demonstrated that phosphorylation of p35 is a crucial factor for fighting against the proapoptotic p25/CDK5 signaling in neuronal apoptosis. Then, in ICH models of rats and primary cortical neurons, we found that the expressions of p75NTR, p-histone H1 (the kinase activity of CDK5), p25, Fas-associated phosphatase-1 (FAP-1), and phosphorylated myocyte enhancer factor 2D (p-MEF2D) were enhanced after ICH, whereas the expression of p35-Thr(138) was attenuated. Coimmunoprecipitation analysis indicated several interactions as follows: p35/p25 and CKD5, p75NTR and p35, as well as p75NTR and FAP-1. After p75NTR or FAP-1 depletion with double-stranded RNA interference in PC12 cells, the levels of p25 and p-histone H1 were attenuated, whereas p35-Thr(138) was elevated. Considering p75NTR has no effect of dephosphorylation, our results suggested that p75NTR might promote the dephosphorylation of p35-Thr(138) via interaction with FAP-1, and the p75NTR/p35 complex upregulated p25/CDK5 signaling to facilitate the neuronal apoptosis following ICH. So, in the study, we aimed to provide a theoretical and experimental basis that p75NTR could be regulated to reduce neuronal apoptosis following ICH for potential clinical treatment.     

Antioxidant Responses of Wheat Seedlings to Exogenous Selenium Supply Under Enhanced Ultraviolet-B

The paper reports the effects of selenium (Se) supply on growth and antioxidant traits of wheat (Triticum aestivum L. cv Han NO.7086) seedlings exposed to enhanced ultraviolet-B (UV-B) stress. Antioxidant responses of seedlings were different depending on the Se concentration. Compared with the control, the lower amount used (0.5 mg Se kg⁻¹ soil) had no significant effect on biomass accumulation. The treatments with 1.0, 2.0, and 3.0 mg Se kg⁻¹ promoted biomass accumulation of wheat seedlings, and the increased amount in biomass was the most at 1.0 mg Se kg⁻¹ treatment. Se treatments with 1.0, 2.0, and 3.0 mg kg⁻¹ also significantly increased activities of peroxidase (POD) and superoxide dismutase (SOD) and reduced the rate of superoxide radical (O₂⁻) production and malondialdehyde (MDA) content of wheat seedlings. In addition, anthocyanins and phenolic compounds content in wheat seedlings evidently increased by the treatments with 1.0 and 2.0 mg Se kg⁻¹. The lower Se treatment had no significant effect on MDA content, although it increased activities of antioxidant enzymes (POD, SOD, and catalase activities) and reduced the rate of O₂⁻ production in wheat seedlings. These results suggest that optimal Se supply is favorable for the growth of wheat seedlings and that optimal Se supply can reduce oxidative stress of seedlings under enhanced UV-B radiation.     

MOTHER OF FT AND TFL1 regulates seed germination and fertility relevant to the brassinosteroid signaling pathway

Brassinosteroids (BRs) are a family of plant steroid hormones that play diverse roles in many aspects of plant growth and development. For example, BRs promote seed germination by counteracting the inhibitory effect of ABA and regulate plant reproductive development, thus affecting seed yield. We have recently reported that MOTHER OF FT AND TFL1 (MFT) regulates seed germination through a negative feedback loop modulating ABA signaling in Arabidopsis. Here, we show that MFT function is also relevant to the BR signaling pathway. In mft loss-of-function mutants, the application of BR could not fully antagonize the inhibitory effect of exogenous ABA on seed germination, suggesting that BR promotes seed germination against ABA partly through MFT. In addition, mft enhances the low-fertility phenotype of det2 in which BR biosynthesis is blocked. This phenotype, together with the observation that MFT is expressed in gametophytes and developing seeds, suggests that MFT and BR play redundant roles in regulating fertility. Therefore, these results suggest that MFT affects seed germination and fertility relevant to the BR signaling pathway.Key words: Arabidopsis, brassinosteroid, abscisic acid, fertility, seed germinationPlant hormones exert profound effects on many fundamental processes during plant growth and development. With respect to seed development and germination, it has long been known that abscisic acid (ABA) and gibberellin (GA) are two major types of phytohormones that play antagonistic roles in regulating these events. Not until recently, another group of phytohormones, namely brassinosteroids (BRs), has also been found to counteract the inhibitory effect of ABA on seed germination.^1,2 In addition, BR has been suggested to act in parallel with GA to promote cell elongation and germination.^1,3,4BRs are a class of polyhydroxysteroids that are found in a wide variety of plant species.⁵ They can be detected in almost every plant tissue, with the highest abundance in the pollen and seeds.⁶ The most active component in the family of BRs is 24-epibrassinolide (BL), which is capable of activating BR signaling.⁶ In Arabidopsis, when the early steps of BR biosynthesis are blocked, the resulting defects include reduced male fertility under normal growth conditions^7,8 and decreased germination percentage in the presence of exogenous ABA.¹ Thus, BR plays an indispensible role in the control of seed development and also contributes to the regulation of seed germination.We have previously reported that MOTHER OF FT AND TFL1 (MFT) responds to both ABA and GA signals to regulate seed germination.⁹ Here we show that MFT functions in regulating seed germination and fertility, which is also relevant to the BR signaling pathway. Thus, MFT seems to function specifically in seeds in response to various phytohormones.     

Catastrophic Health Expenditure and Rural Household Impoverishment in China: What Role Does the New Cooperative Health Insurance Scheme Play?

Objective

To determine whether the New Cooperative Medical Insurance Scheme (NCMS) is associated with decreased levels of catastrophic health expenditure and reduced impoverishment due to medical expenses in rural households of China.

Methods

An analysis of a national representative sample of 38,945 rural households (129,635 people) from the 2008 National Health Service Survey was performed. Logistic regression models used binary indicator of catastrophic health expenditure as dependent variable, with household consumption, demographic characteristics, health insurance schemes, and chronic illness as independent variables.

Results

Higher percentage of households experiencing catastrophic health expenditure and medical impoverishment correlates to increased health care need. While the higher socio-economic status households had similar levels of catastrophic health expenditure as compared with the lowest. Households covered by the NCMS had similar levels of catastrophic health expenditure and medical impoverishment as those without health insurance.

Conclusion

Despite over 95% of coverage, the NCMS has failed to prevent catastrophic health expenditure and medical impoverishment. An upgrade of benefit packages is needed, and effective cost control mechanisms on the provider side needs to be considered.     

Responses of Wheat Roots to Exogenous Selenium Supply Under Enhanced Ultraviolet-B

Effects of selenium (Se) on growth and some physiological traits of roots in wheat (Triticum aestivum L. cv Han NO.7086) seedlings exposed to enhanced ultraviolet-B (UV-B) stress are reported. Responses of roots were different depending on the Se concentration. Compared with the control, root weight of wheat seedlings treated with 1.0 and 2.0 mg Se kg⁻¹ soil increased by 39.47% and 16.28%, respectively. The lower amount Se (0.5 mg kg⁻¹) and the higher amount Se treatments (3.0 mg kg⁻¹) did not significantly affect on root weight. Se treatments significantly increased root activity, flavonoids and proline content, and activities of peroxidase and superoxide dimutase in wheat roots exposed to enhanced UV-B. In addition, the treatments with 0.5, 1.0, and 2.0 mg Se kg⁻¹ significantly reduced malondialdehyde content and the rate of superoxide radical (O₂⁻) production of roots, whereas the higher amount Se treatment only induced a decrease in the rate of O₂⁻ production. The results of this study demonstrated that optimal Se supply promoted roots growth of wheat seedlings, and that optimal Se supply could reduce oxidative stress in wheat roots under enhanced UV-B radiation.