稳定性同位素示踪复杂土壤中微生物DNA/RNA的技术难点是13C-DNA/RNA的鉴定。本研究针对我国六种典型水稻土,利用稳定性同位素13CH4示踪活性的甲烷氧化菌,超高速密度梯度离心获得不同浮力密度DNA/RNA后,以甲烷氧化菌独有的pmo A功能基因...稳定性同位素示踪复杂土壤中微生物DNA/RNA的技术难点是13C-DNA/RNA的鉴定。本研究针对我国六种典型水稻土,利用稳定性同位素13CH4示踪活性的甲烷氧化菌,超高速密度梯度离心获得不同浮力密度DNA/RNA后,以甲烷氧化菌独有的pmo A功能基因和16S r RNA特异基因作为分子标靶,通过半定量凝胶电泳技术评价了特异基因作为分子标靶判定13C-DNA/RNA的可行性,进一步利用克隆文库技术研究水稻土中的活性甲烷氧化菌群落结构。结果表明:甲烷氧化菌功能基因pmo A作为分子标靶,能够准确鉴别13C-DNA,而甲烷氧化菌特异的16S r RNA基因则能较好地区分12C和13C标记的RNA,但13C-RNA中的非目标微生物污染高于13C-DNA示踪技术。进一步以13C-DNA和13C-RNA为模板,分别构建了pmo A和16S r RNA基因的克隆文库,系统发育分析表明I型菌主导了土壤甲烷氧化过程,其中江西鹰潭和黑龙江五常土壤中活性甲烷氧化菌全部属于Ia型,而四川资阳、浙江嘉兴、江苏常熟和江都土壤中Ia型和Ib型甲烷氧化菌均有发现,并且后者比例较低。这些结果表明分子标靶基因能够有效判定复杂土壤中的甲烷氧化菌13C-DNA/RNA,在DNA和RNA水平的结果基本一致,我国典型水稻土中活性甲烷氧化菌可能存在一定的地理分异规律。展开更多
Objective: To examine if correlates of HIV-1 genital shedding in crosssectional studies can be used to determine the risk of shedding in individual HIV-1-positive women. Study design: Longitudinal samples from blood...Objective: To examine if correlates of HIV-1 genital shedding in crosssectional studies can be used to determine the risk of shedding in individual HIV-1-positive women. Study design: Longitudinal samples from blood and cervix were obtained from 18 HIV-1 infected women, and HIV-1 RNA and cellassociated DNA virus, and betachemokine levels, were measured. Associations between variables were analyzed at both individual and group level. Results: The variation over time was 2.9-, 2.1-, and 2.3-fold in plasma RNA, PBMC DNA and cervical RNA load, respectively, and reached 6.2-fold in cervical DNA load. Differences were observed between associations in individualand grouplevel comparisons, suggesting that a separate reservoir of HIV replication may exist in the genital tract of some women, which is influenced by local environmental factors. Conclusions: Our study underscores the importance of caution during contact with genital fluids at all stages of infection and disease regardless of treatment and HIV-1 blood loads.展开更多
Bckground and Objective: Various factors affect the radioresistance of tumor cells, with unknown molecular mechanism(s). Many genes have been found to associate with the radioresistance of tumor cells, however, the pr...Bckground and Objective: Various factors affect the radioresistance of tumor cells, with unknown molecular mechanism(s). Many genes have been found to associate with the radioresistance of tumor cells, however, the precise mechanism of these genes have not been elucidated. This paper was to analyze the differential expressions of DNA repair genes in esophageal carcinoma cells at different time after X-ray irradiation, and to investigate the role of these DNA repair genes in radiation resistance. Methods: Esophageal cancer parental cells Seg-1 were treated with continuous 2 Gy of fractionated irradiation until the total dose reached 60 Gy to establish the radioresistant cell line Seg-1R. Total RNA was extracted from each cell line at 0, 8, and 24 h after irradiation. Illumine Human-6 V3 microarray was used to identify differentially expressed genes between parental and radioresistant cells. Ten genes involved in DNA repair were obtained and their expressions at different time points after irradiation were analyzed by Gene Ontology analysis. Results: Ten DNA repair associated genes were found to be differentially expressed. Three of these genes, SLK, HMGB1, and PMS1, were not only differentially expressed between parental and radioresistant cell lines, but also expressed differently at different time points after irradiation in the same cell line. Conclusions: PMS1 may be an important factor involved in the mechanism of radioresistance of esophageal carcinoma cells.展开更多
文摘稳定性同位素示踪复杂土壤中微生物DNA/RNA的技术难点是13C-DNA/RNA的鉴定。本研究针对我国六种典型水稻土,利用稳定性同位素13CH4示踪活性的甲烷氧化菌,超高速密度梯度离心获得不同浮力密度DNA/RNA后,以甲烷氧化菌独有的pmo A功能基因和16S r RNA特异基因作为分子标靶,通过半定量凝胶电泳技术评价了特异基因作为分子标靶判定13C-DNA/RNA的可行性,进一步利用克隆文库技术研究水稻土中的活性甲烷氧化菌群落结构。结果表明:甲烷氧化菌功能基因pmo A作为分子标靶,能够准确鉴别13C-DNA,而甲烷氧化菌特异的16S r RNA基因则能较好地区分12C和13C标记的RNA,但13C-RNA中的非目标微生物污染高于13C-DNA示踪技术。进一步以13C-DNA和13C-RNA为模板,分别构建了pmo A和16S r RNA基因的克隆文库,系统发育分析表明I型菌主导了土壤甲烷氧化过程,其中江西鹰潭和黑龙江五常土壤中活性甲烷氧化菌全部属于Ia型,而四川资阳、浙江嘉兴、江苏常熟和江都土壤中Ia型和Ib型甲烷氧化菌均有发现,并且后者比例较低。这些结果表明分子标靶基因能够有效判定复杂土壤中的甲烷氧化菌13C-DNA/RNA,在DNA和RNA水平的结果基本一致,我国典型水稻土中活性甲烷氧化菌可能存在一定的地理分异规律。
文摘Objective: To examine if correlates of HIV-1 genital shedding in crosssectional studies can be used to determine the risk of shedding in individual HIV-1-positive women. Study design: Longitudinal samples from blood and cervix were obtained from 18 HIV-1 infected women, and HIV-1 RNA and cellassociated DNA virus, and betachemokine levels, were measured. Associations between variables were analyzed at both individual and group level. Results: The variation over time was 2.9-, 2.1-, and 2.3-fold in plasma RNA, PBMC DNA and cervical RNA load, respectively, and reached 6.2-fold in cervical DNA load. Differences were observed between associations in individualand grouplevel comparisons, suggesting that a separate reservoir of HIV replication may exist in the genital tract of some women, which is influenced by local environmental factors. Conclusions: Our study underscores the importance of caution during contact with genital fluids at all stages of infection and disease regardless of treatment and HIV-1 blood loads.
基金National Natural Science Foundation of China (No.30670619)
文摘Bckground and Objective: Various factors affect the radioresistance of tumor cells, with unknown molecular mechanism(s). Many genes have been found to associate with the radioresistance of tumor cells, however, the precise mechanism of these genes have not been elucidated. This paper was to analyze the differential expressions of DNA repair genes in esophageal carcinoma cells at different time after X-ray irradiation, and to investigate the role of these DNA repair genes in radiation resistance. Methods: Esophageal cancer parental cells Seg-1 were treated with continuous 2 Gy of fractionated irradiation until the total dose reached 60 Gy to establish the radioresistant cell line Seg-1R. Total RNA was extracted from each cell line at 0, 8, and 24 h after irradiation. Illumine Human-6 V3 microarray was used to identify differentially expressed genes between parental and radioresistant cells. Ten genes involved in DNA repair were obtained and their expressions at different time points after irradiation were analyzed by Gene Ontology analysis. Results: Ten DNA repair associated genes were found to be differentially expressed. Three of these genes, SLK, HMGB1, and PMS1, were not only differentially expressed between parental and radioresistant cell lines, but also expressed differently at different time points after irradiation in the same cell line. Conclusions: PMS1 may be an important factor involved in the mechanism of radioresistance of esophageal carcinoma cells.
