红串红球菌USTB-03对4,6-二甲基二苯并噻吩的脱硫研究

分离出1株能够对4,6-二甲基二苯并噻吩(4,6-DMDBT)进行高效脱硫的微生物菌种,经中国科学院微生物研究所鉴定为红串红球菌USTB-03。研究结果表明,与甘油和乙醇相比,葡萄糖是促进红串红球菌USTB-03生长和提高其脱硫比活性的最好碳源,最高脱硫比活性可达298.1mmol4,6-DMDBT/(kg·h)。在初始pH从4.0到9.0范围内,pH7.0可以使红串红球菌USTB-03保持最大的脱硫比活性。进一步研究显示,红串红球菌USTB-03对4,6-DMDBT脱硫后的最终代谢产物是3,3-二甲基-2-羟基联苯(2-HDMBP),只有C-S键被切断,而C-C键未受到破坏。该脱硫途径类似于二苯并噻吩(DBT)特异性脱硫的途径。     

伤寒沙门菌激活TRAIL信号通路促进巨噬细胞凋亡

为探究伤寒沙门菌对巨噬细胞凋亡及肿瘤坏死因子相关凋亡诱导配体(tumor necrosis factor-related apoptosis inducing ligand,TRAIL)信号通路的影响,对伤寒沙门菌感染THP-1细胞早期和后期提取细胞RNA进行转录组测序(RNA-seq).通过定量PCR(qPCR)技术检测凋亡相关基因的转录水平,对RNA-seq结果进行验证,流式细胞术和蛋白质免疫印迹法检测THP-1细胞的凋亡和凋亡相关蛋白;加入TRAIL抗体结合TRAIL蛋白后,流式细胞术和蛋白质免疫印迹法检测感染早期THP-1细胞凋亡的变化.结果显示,伤寒沙门菌感染THP-1细胞后,凋亡相关基因caspase-3、caspase-8、caspase-9在感染后期转录水平显著增加,Tnfsf10、Tnfrsf10b、Tnf、Fas在感染早期和后期转录均增加,细胞凋亡率明显增加,caspase-3、caspase-8、caspase-9蛋白活化增加,TRAIL、DR5蛋白表达增加;与PBS对照组相比,加入TRAIL抗体后caspase-3蛋白活化明显减弱,细胞凋亡率明显下降.综上,伤寒沙门菌通过部分激活TRAIL信号通路来诱导巨噬细胞凋亡.     

暗发酵制氢代谢途径研究进展

氢能因具备高热值、燃烧产物无污染、原料来源广泛等优点成为最具潜力的新能源之一。暗发酵因不受光照限制，产氢能力强，并可以解决环境污染问题而成为研究的热点。该文主要综述了暗发酵制氢的代谢途径及其研究进展，重点阐述了产氢菌株关键酶或基因改造的最新研究成果，并对其未来的应用进行了展望。     

血吸虫血红蛋白降解途径的重构及关键酶蛋白保守结构域的分析

利用生物信息学方法,以疟原虫的血红蛋白降解途径为基础,成功地构建出了日本血吸虫和曼氏血吸虫的血红蛋白降解途径,并对降解途径上的关键酶蛋白的保守结构域进行了序列及结构分析。预测得到的血吸虫血红蛋白降解酶保守结构域,与疟原虫相比,在序列上催化位点高度保守,在结构上空间相对位置较一致,为研究血吸虫血红蛋白降解酶,及其与底物或...     

DLL1-ICD基因真核表达载体的构建及转染鉴定

通过克隆DLL1-ICD(Delta-like1细胞内区域)的cDNA及测序鉴定,构建pEGFP-C1-DLL-ICD真核表达载体并进行细胞转染,为研究Notch信号通路与Neuritin的关系奠定基础。首先根据小鼠全长DLL1 cDNA序列,设计DLL-ICD PCR引物,以小鼠胎脑cDNA文库为模板,利用PCR技术扩增DLL1-ICD cDNA。将扩增出的基因片段克隆至pEGFP-C1载体,进行DNA序列测定。并进一步将测序正确的pEGFP-C1-DLL1-ICD真核表达载体转染HEK293细胞。结果显示:成功克隆了DLL1-ICD的cDNA片段,测序结果与基因文库中的DLL1-ICD序列一致,并在转染真核细胞后获得了较好地表达。表明pEGFP-C1-DLL1-ICD真核表达载体构建成功,并在293细胞中成功表达了DLL1-ICD-EGFP融合蛋白。研究结果为进一步探讨Notch信号通路与神经系统疾病的分子机制奠定基础。     

钩藤中钩藤碱对肿瘤坏死因子-α诱导人星型胶质细胞炎症模型作用机制研究

目的研究钩藤中钩藤碱对肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)诱导人星型胶质细胞(Human Astrocytes,HA)的炎症模型的作用机制.方法:体外培养HA,用TNF-α诱导HA造模,将细胞分为正常组、模型组、钩藤碱组、依达拉奉组.采用噻唑蓝(MTT)法检测钩藤碱对HA增殖能力的影响,用逆转录PCR法(RT-PCR)检测一氧化氮合酶(nitric oxide synthase,NOS)mRNA、白细胞介素-23(interleukin-23,IL-23)mRNA、白细胞介素-6(interleukin-6,IL-6)mRNA的表达,用分光光度法检测一氧化氮(nitric oxide,NO)、超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malondialdehyde,MDA)的表达,用蛋白免疫印迹法(Western blot)检测p-mTOR,mTOR,p-Stat3和Stat3的蛋白表达.结果与正常组比较,32ng·mL-1的TNF-α对星形胶质细胞有明显抑制作用(P0.001);400μmol·L~(-1)的钩藤碱对星形胶质细胞活力有明显抑制作用(P0.001).与模型组相比,200μmol·L~(-1)的钩藤碱对模型细胞有明显的增殖作用(P0.01);钩藤碱组和依达拉奉组NOS mRNA,NO和SOD都显著上升(P0.001),IL-23mRNA,IL-6mRNA和MDA都显著下降(P0.001);钩藤碱组p-mTOR/mTOR和p-Stat3/Stat3都显著下降(P0.01).结论钩藤有效成分钩藤碱具有抑制TNF-α诱导HA炎症的损伤作用,可能是通过下调mTOR/STAT3信号通路增加氧化相关因子NOS,NO,SOD的表达,减少氧化相关因子MDA以及炎症相关因子IL-23和IL-6的表达.     

复杂网络分析激酶底物信号传递机制

为了研究信号从激酶到达底物蛋白质后的传递机制,本文将磷酸化和蛋白质相互作用结合构建网络,利用复杂网络理论对该网络进行分析.结果发现,底物中存在的社区结构不会只传递特定激酶组的信号,影响网络稳定性的关键节点大多参与肿瘤发生相关的信号途径.     

Molecular dynamics simulation of RNA pseudoknot unfolding pathway

Many biological functions of RNA molecules are related to their pseudoknot structures. It is significant for predicting the structure and function of RNA that learning about the stability and the process of RNA pseudoknot folding and unfolding. The structural features of mouse mammary tumor virus (MMTV) RNA pseudoknot in different ion concentration, the unfolding process of the RNA pseudoknot, and the two hairpin helices that constitute the RNA pseudoknot were studied with all atom molecule dynamics simulation method in this paper. We found that the higher cation concentration can cause structure of the RNA molecules more stable, and ions played an indispensable role in keeping the structure of RNA molecules stable; the unfolding process of hairpin structure was corresponding to the antiprocess of its folding process. The main pathway of pseudoknot unfolding was that the inner base pair opened first, and then, the two helices, which formed the RNA pseudoknot opened decussately, while the folding pathway of the RNA pseudoknot was a helix folding after formation of the other helix. Therefore, the unfolding process of RNA pseudoknot is different from the antiprocess of its folding process, and the unfolding process of each helix in the RNA pseudoknot is similar to the hairpin structure’s unfolding process, which means that both are the unzipping process.     

Aerosol oxalate and its implication to haze pollution in Shanghai, China

A total of 238 samples of PM2.5and TSP were analyzed to study the characteristics,sources,and formation pathways of aerosol oxalate in Shanghai in four seasons of 2007.The concentrations of oxalate were0.07–0.41 lg/m3in PM2.5and 0.10–0.48 lg/m3in TSP,respectively.Oxalate displayed a seasonal variation of autumn[summer[winter[spring in both PM2.5and TSP and was dominantly present in PM2.5in all samples.Correlation between oxalate and K?and high ratio of oxalate/K?suggested that biomass burning was a secondary source of aerosol oxalate in Shanghai,in addition to urban VOCs sources(vehicular and industrial emissions),especially in autumn.Secondary formation accounted for the majority of aerosol oxalate in Shanghai,which was supported by the high correlation of oxalate with nssSO42-,K?and NO3-,proceeding from different mechanisms.Relatively high ambient RH together with high cloud cover was found benefiting the secondary formation of aerosol oxalate.The in-cloud process(aqueous-phase oxidation)was proposed to be likely the major formation pathway of aerosol oxalate in Shanghai,which was supported by the high correlation of oxalate with nss-SO42-and K?,dominant residence of oxalate in droplet mode and result of favorable meteorological condition analysis.High correlation of oxalate and NO3-reflected the OH radical involved oxidation chemistry of the two species in the atmosphere and also suggested that gas-particle surface reactions and the evaporation–condensation process were both possible secondary formation pathways of aerosol oxalate in coarser particle mode([1.0 lm).As a major water-soluble organic compound in aerosols,concentration of oxalate showed a distinct negative correlation to the atmospheric visibility,which implied that aerosol organic compounds could play an important role in haze pollution as well as in air quality in Shanghai.