一株异养型亚硝酸盐氧化细菌的分离及其降解特性的研究

以亚硝酸盐和琥珀酸钠作为惟一氮、碳源从活性污泥中筛选分离一株能够高效氧化亚硝酸盐的硝化菌株,并对其形态学、生理生化及16S rDNA同源性进行分析,在此基础上研究pH、温度、转速、初始亚硝基氮的浓度以及盐浓度对其氧化亚硝酸盐的影响。结果显示,在好氧条件下,该菌株能在12 h内将356.004 mg/L亚硝酸盐降解99.53%。根据形态学特征、生理生化特性以及16S rRNA同源性分析,初步将该菌株鉴定为施氏假单胞菌(Pseudomonas stutzeri),并将其命名为LYS-86。该菌株氧化亚硝酸盐的最适pH8.0-10.0,温度30℃,转速180 r/min,盐浓度1 g/L。当培养基中初始亚硝酸盐浓度为0.5 g/L时,菌株LYS-86的硝化活性最高,随着培养基中初始亚硝基氮浓度的不断提高,菌株LYS-86的硝化活性会不断下降。本研究利用硝化细菌选择性培养基从活性污泥中筛选到了一株异养型亚硝酸氧化菌菌株,该菌株具有高效的硝化活性,为今后该菌株的实际应用及理论研究奠定了基础。     

Tumor-suppressive effects of psoriasin (S100A7) are mediated through the β-catenin/T cell factor 4 protein pathway in estrogen receptor-positive breast cancer cells

Psoriasin (S100A7) is expressed in several epithelial malignancies including breast cancer. Although S100A7 is associated with the worst prognosis in estrogen receptor α-negative (ERα(-)) invasive breast cancers, its role in ERα-positive (ERα(+)) breast cancers is relatively unknown. We investigated the significance of S100A7 in ERα(+) breast cancer cells and observed that S100A7 overexpression in ERα(+) breast cancer cells, MCF7 and T47D, exhibited decreased migration, proliferation, and wound healing. These results were confirmed in vivo in nude mouse model system. Mice injected with S100A7-overexpressing MCF7 cells showed significant reduction in tumor size compared with mice injected with vector control cells. Further mechanistic studies revealed that S100A7 mediates the tumor-suppressive effects via a coordinated regulation of the β-catenin/TCF4 pathway and an enhanced interaction of β-catenin and E-cadherin in S100A7-overexpressing ERα(+) breast cancer cells. We observed down-regulation of β-catenin, p-GSK3β, TCF4, cyclin D1, and c-myc in S100A7-overexpressing ERα(+) breast cancer cells. In addition, we observed increased expression of GSK3β. Treatment with GSK3β inhibitor CHIR 99021 increased the expression of β-catenin and its downstream target c-myc in S100A7-overexpressing cells. Tumors derived from mice injected with S100A7-overexpressing MCF7 cells also showed reduced activation of the β-catenin/TCF4 pathway. Therefore, our studies reveal for the first time that S100A7-overexpressing ERα(+) breast cancer cells exhibit tumor suppressor capabilities through down-modulation of the β-catenin/TCF4 pathway both in vitro and in vivo. Because S100A7 has been shown to enhance tumorigenicity in ERα(-) cells, our studies suggest that S100A7 may possess differential activities in ERα(+) compared with ERα(-) cells.     

Draft genome sequence of Streptomyces coelicoflavus ZG0656 reveals the putative biosynthetic gene cluster of acarviostatin family α-amylase inhibitors

Aims: The aims of this study are to obtain the draft genome sequence of Streptomyces coelicoflavus ZG0656, which produces novel acarviostatin family α‐amylase inhibitors, and then to reveal the putative acarviostatin‐related gene cluster and the biosynthetic pathway. Methods and Results: The draft genome sequence of S. coelicoflavus ZG0656 was generated using a shotgun approach employing a combination of 454 and Solexa sequencing technologies. Genome analysis revealed a putative gene cluster for acarviostatin biosynthesis, termed sct‐cluster. The cluster contains 13 acarviostatin synthetic genes, six transporter genes, four starch degrading or transglycosylation enzyme genes and two regulator genes. On the basis of bioinformatic analysis, we proposed a putative biosynthetic pathway of acarviostatins. The intracellular steps produce a structural core, acarviostatin I00‐7‐P, and the extracellular assemblies lead to diverse acarviostatin end products. Conclusions: The draft genome sequence of S. coelicoflavus ZG0656 revealed the putative biosynthetic gene cluster of acarviostatins and a putative pathway of acarviostatin production. Significance and Impact of the Study: To our knowledge, S. coelicoflavus ZG0656 is the first strain in this species for which a genome sequence has been reported. The analysis of sct‐cluster provided important insights into the biosynthesis of acarviostatins. This work will be a platform for producing novel variants and yield improvement.     

大口鲇和鲇鱼血清蛋白质及同工酶的比较研究

采用聚丙烯酰胺梯度凝胶垂直板电泳,分析了大口鲇和鲇鱼的血清蛋白质以及心脏、肝脏、眼和肌肉4种组织的EST及MDH同工酶。结果表明,大口鲇和鲇鱼的血清蛋白质均能分离出20条左右的谱带,两者既表现出相同的谱带,又表现出迁移率和含量都不同的带型。两者的EST和MDH同工酶在4种组织及血清中均能特异性地表达,存在明显的组织和物种特异性。本文认为肝脏是研究大口鲇和鲇鱼种群生化遗传结构与变异的理想材料,同时还探讨了两种鲇鱼的M DH同工酶位点。 Abstract:The serum proteins and isozymes in four tissues (heart,liver,eye and musele)of Smeridionalis Chen and S.asotus Linnaeus were analyzed by polyacrylamide gradient gel vertical electrophoresis.The isozymes are esterase(EST)and malate dehytrogenase(MDH).The results showed that electrophoretograme of serum proteins were about 20 protein pattens in two species catfish,they were either the same protein pattens or the different pattens.Electrophoretogram of isozymes(EST,MDH)in two species catfish indicated tissues and species specificity.Experiment considered that the liver was a good material studied biochemical genetic constitution and variation in species group of S.meridionalis Chen and S.asotus Linnaeus.     

共培养的树突状细胞与CIK细胞的体外增殖和杀瘤活性研究

本文观察树突状细胞与同源CIK细胞共培养后培养物的表型、增殖活性变化,及DC对CIK细胞细胞毒活性的影响。提取健康供血者的PBMC,常规诱导出DC与CIK细胞,用A549肺腺癌细胞裂解液抗原冲击DC,并和CIK细胞共培养,动态观察DC-CIK培养物增殖活性和表型变化;定量检测细胞培养上清中的IFN-γ和IL-12;并用MTT法检测共培养细胞杀伤A549肺腺癌细胞和BEL-7404肝癌细胞的活性。结果表明DC与CIK细胞共培养,通过彼此的相互作用诱导出比CIK细胞增殖活性和杀伤活性更强的细胞群体。经A549肺腺癌细胞裂解液抗原冲击的DC活化的CIK,对A549肺腺癌细胞的杀伤活性高于单纯CIK细胞,差异显著(p<0.05)。二者对BEL-7404肝癌细胞的杀伤活性无显著差异。实验证明DC与CIK共培养细胞是一种增殖活性和细胞毒活性高于CIK细胞的免疫活性细胞,经肿瘤抗原冲击的DC能明显提高CIK对肿瘤细胞的杀伤活性,具有更广阔的应用前景。     

Differential pattern of spinal sympathetic outflow in response to stimulation of the caudal medullary raphe

In urethan-anesthetized cats, frequency domain analysis was used to explore the mechanisms of differential responses of inferior cardiac (CN), vertebral (VN), and renal (RN) sympathetic nerves to electrical stimulation of a discrete region of the medullary raphe (0-2 mm caudal to the obex). Raphe stimulation in baroreceptor-denervated cats at frequencies (7-12 Hz) that entrained the 10-Hz rhythm in nerve activity decreased CN and RN activities but increased VN activity. The reductions in CN and RN discharges were associated with decreased low-frequency (相似文献   

假单胞菌L-半胱氨酸合成酶的纯化和性质研究

假单胞菌TS-1138的细胞浆液通过硫铵沉淀、SephadexG-75凝胶过滤、DEAE-Cellulose52离子交换、SephadexG 100凝胶过滤等分离纯化手段分别将从L-ATC合成L 半胱氨酸的两个酶——L-ATC水解酶和L-SCC水解酶纯化了 83.9和 90.3倍。SDS-PAGE鉴定均为单一条带 ,两种酶的相对分子质量分别为 37.5和 42.8kD ;酶反应的最适温度均为 35℃ ,最适pH分别为 7.0和 8.0 ;酶的米氏常数分别为 0.67mmol L和 0.15mmol L ,     

中国科学院内蒙古草原生态系统定位站学术交流会在京召开

中国科学院内蒙古草原生态系统定位站学术交流会已于1981年1月29日至2月3日在北京召开。参加这次会议的有中国科学院植物研究所、动物研究所、综合考察委员会及内蒙古大学等17个单位,42人。