放线共生放线杆菌表面相关物质对人牙龈成纤维细胞DNA合成和细胞周期的影响

目的观察放线共生放线杆菌表面相关物质对人牙龈成纤维细胞的DNA合成和细胞周期的影响。方法应用流式细胞仪技术。结果100mg/L组明显抑制细胞DNA合成，细胞增殖指数（S+G2M）%降低（P<0.05）。结论此物质不仅抑制细胞的分裂、增殖，而且还抑制细胞的DNA合成。     

脑脊液中Tau蛋白及Aβ检测对老年期痴呆早期诊断的意义

目的:探讨脑脊液(cerebrospinalfluid,CSF)中Tau蛋白及β-淀粉样蛋白(β-amyloidprotein,Aβ)对老年期痴呆(seniledementia,SD)主要包括老年性痴呆(Alzheimer'sdisease,AD)及脑血管病性痴呆(vasculardementia,VD)的诊断价值。方法:采用双抗体夹心酶联免疫吸附法(ELISA)检测54例AD患者,43例VD患者及30例正常对照者(normalcontrols,NC)脑脊液中Tau蛋白及Aβ1-42浓度。结果:老年期痴呆患者CSF中;①Tau蛋白浓度高于正常对照者(P<0.05);②Aβ1-42浓度低于正常对照者(P<0.05);③根据CSF中Tau蛋白、Aβ1-42浓度检测诊断老年期痴呆的灵敏度分别为51.55%、45.36%;特异性分别为90.90%、93.62%;结合Tau蛋白浓度及Aβ1-42浓度诊断SD的灵敏度为74.23%,特异性为93.33%。结论:临床上检测CSF中Tau蛋白、Aβ1-42浓度可作为早期诊断老年期痴呆的辅助指标。     

维甲酸对小鼠T细胞增殖及骨破坏因子RANKL表达的研究

目的 探讨全反式维甲酸对体外培养的小鼠T淋巴细胞的增殖及核因子-КB受体活化因子配体(RANKL)表达的调节作用及相关机制。方法 体外分离Aa感染的BALB/C小鼠颈T淋巴细胞,分别加入浓度为0、1×10-8、1×10-7、1×10-6、1×10-5mol/L的全反式维甲酸,培养3 d后,取100μl上清保存在-70℃冰箱中,以备sRANKL及IL-10等细胞因子的测定;另加入100μl含有3Hthymidine(0.5μCi/孔)RPMI培养液继续培养18 h,进行T细胞3H增殖率测定。结果 维甲酸处理组与非处理组相比,T细胞3H增殖率下降;上清中RANKL的表达水平下降,IL-10的表达水平增强(P<0.05),二者具有负相关性(r=-0.774,P=0.001),且呈剂量依赖性。结论 维甲酸可通过上调IL-10的表达并下调T细胞上的RANKL的表达水平,抑制T细胞的免疫功能,且呈剂量依赖性。     

寡核苷酸探针检测龋下菌斑中伴放线菌放线杆菌的分布

目的研究伴放线菌放线杆菌在牙周炎患者和健康人龈下菌斑中的分布。方法利用合成的寡核苷酸探针对60例慢性牙周炎患者60患病位点、10例健康人的10个对照位点龈下菌斑中伴放线菌放线杆菌进行检测。结果60个患病位点中有19位点检出伴放线菌放线杆菌，检出率为31.67%,在健康部位未检测出伴放线菌放线杆菌，二者差异有统计学意义(P<0.05)；检出伴放线菌放线杆菌的患者的年龄是(28.68±7.33)岁,未检出伴放线菌放线杆菌的患者的年龄是(44.48±12.48)岁,二者差异有统计学意义(P<0.01)。结论伴放线菌放线杆菌与年轻患者慢性牙周炎的发生、发展密切相关。     

苏云金芽孢杆菌杀蚊蛋白基因cry11Aa的克隆与表达

目的 克隆苏云金芽孢杆菌以色列亚种的杀蚊毒素蛋白基因cry11 Aa，并使其在酵母双杂交系统受体菌Saccharomyces cerevisiae L40中获得表达。方法 应用聚合酶链反应扩增获得cry11 An基因，构建表达载体pHybLex／Zeo-cry11 Aa，转化到酵母菌Saccharomyces cerevisiae L40。结果 用CryllAa抗体和LexA抗体进行的Western blot免疫杂交表明cry11Aa基因在酵母菌L40中成功表达，生成了Cry11 Aa-LexA融合蛋白。结论 成功地克隆、表达了cry11Aa基因，为进一步利用酵母双杂交系统寻找与毒素蛋白Cry11Aa特异性结合的蚊幼中肠受体蛋白，揭示苏云金芽孢杆菌毒杀蚊虫的分子生物学机制奠定了基础。     

Assessing the potential for interaction between the insecticidal activity of two genetically engineered cotton events combined by conventional breeding: An example with COT102 × MON 15985

Bollgard^® III was developed by combining cotton events COT102 and MON 15985 through conventional breeding to improve efficacy against lepidopteran feeding damage. COT102 produces the Vip3Aa19 protein and MON 15985 produces the Cry1Ac and Cry2Ab2 proteins. COT102 × MON 15985 has also been bred with Roundup Ready Flex^® cotton (MON 88913) that confers glyphosate tolerance. This study evaluated the activity of COT102 and MON 15985 and the combined activity of COT102 and MON 15985 against the cotton bollworm (CBW, Helicoverpa zea). COT102, MON 15985, COT102 × MON 15985 and COT102 × MON 15985 × MON 88913 have comparable Vip3Aa19 and/or Cry1Ac, Cry2Ab2 protein expression levels as determined by enzyme-linked immunosorbent assay. CBW demonstrated concentration-dependent growth inhibition after 7-days of feeding on lyophilized leaf tissue derived from COT102, MON 15985, COT102 × MON 15985 and COT102 × MON 15985 × MON 88913 incorporated into an artificial diet. Observed EC₅₀ values for COT102 × MON 15985 and COT102 × MON 15985 × MON 88913 were comparable (≤4% deviation) with the predicted EC₅₀ value under the assumption of additivity using the combined activity of COT102 and MON 15985. No interaction in biological activity between COT102 and MON 15985 is consistent with results from competition and ligand blotting assays that demonstrated that Vip3Aa does not inhibit the binding of either Cry1Ac or Cry2Ab2 and vice versa. The results from this study demonstrate that the activity of COT102 × MON 15985 against CBW is consistent with predictions of additivity.     

Flexibility Analysis of Bacillus thuringiensis Cry1Aa

Objective To investigate the flexibility and mobility of the Bacillus thuringiensis toxin Cry1Aa.
Methods The graph theory-based program Constraint Network Analysis and normal mode-based program NMsim were used to analyze the global and local flexibility indices as well as the fluctuation of individual residues in detail.
Results The decrease in Cry1Aa network rigidity with the increase of temperature was evident. Two phase transition points in which the Cry1Aa structure lost rigidity during the thermal simulation were identified. Two rigid clusters were found in domains I and II. Weak spots were found in C-terminal domain III. Several flexible regions were found in all three domains;the largest residue fluctuation was present in the apical loop2 of domain II.
Conclusion Although several flexible regions could be found in all the three domains, the most flexible regions were in the apical loops of domain II.