龙眼胚性培养物蛋白质水平双向电泳技术体系的建立

以龙眼胚性培养物为材料,使用Pharmacia多功能水平电泳仪(Multiphor ),采用滤纸半干电泳与梯度凝胶技术,建立了适合于龙眼胚性培养物的蛋白质水平双向电泳技术体系.使用该技术有望对龙眼体细胞胚胎发生过程中特异蛋白进行研究.

应用PCR-DGGE技术研究处理含氨废气的生物滤塔中微生物多样性

变性梯度凝胶电泳技术 (DGGE)在微生物生态学领域有着广泛的应用 .本文应用DGGE技术对处理含氨废气的生物滤塔中微生物多样性随时间的变化进行了研究 .在生物滤塔运行的不同时间采集滤塔中的填料样品 ,进行了生物滤塔对氨处理效果的分析和DGGE分析 .结果显示 ,污泥和混合填料生物滤塔氨的出气浓度在经过一段时间后 ,逐渐升高 ,而堆肥生物滤塔的运行情况较好 ,对氨的去除效率始终在 98%以上 .PCR DGGE图谱显示 ,不同时间的相同填料中微生物DGGE图谱有着明显的差异性 .Shannon指数分析表明 ,填料中微生物的多样性都随着反应器运行时间的延长而有所减少 .运行一个月后 ,混合填料的微生物多样性指数最低为 0 389;其次为污泥填料 ,其多样性指数为 0 4 73;堆肥填料的微生物多样性程度最高为0 5 6 9.生物滤塔对氨的去除效果与填料中微生物多样性Shannon指数之间有一定的相关关系 .主成分分析 (PCA)显示对于堆肥和污泥来说 ,填料样品之间微生物群落结构相似性较高 。

Bacterial Diversity of Gut Content in Sea Cucumber(Apostichopus japonicus) and Its Habitat Surface Sediment

This study investigated the bacterial diversity of gut content of sea cucumber （Apostichopus japonicus） and its habitat surface sediment in a bottom enhancement area using PCR-based denaturing gradient gel electrophoresis （DGGE） technique. Bacte- rial diversity evaluation showed that the value of the Shannon-Wiener index of gut content in different intestinal segments of A. ja-ponicus varied between 2.88 and 3.00, lower than that of the surrounding sediment （3.23）. Phyl0genetic analysis showed that bacte- rial phylotypes in gut content and the surrounding sediment ofA. japonicus were closely related to Proteobacteria including3,-, ct-, 8- and e-proteobacteria, Bacteroidetes, Firmicute, and Actinobacteria, of which 7-proteobacteria were predominant. These results sug- gested that the sea cucumber A. japonicus was capable of feeding selectively, and PCR-DGGE was applicable for characterizing the bacterial community composition in gut content and the surrounding sediment of sea cucumber. Further investigation targeting longer 16S rDNA gene fragments and/or functional genes was recommended for obtaining more information of the diversity and function of bacterial community in the gut content of sea cucumber.

Bacterial diversity, composition and temporal-spatial variation in the sediment of Jiaozhou Bay, China

Studies on the diversity and distribution of bacterial populations will improve the overall understanding of the global patterns of marine bacteria and help to comprehend local biochemical processes and environments. We evaluated the composition and the dynamics of bacterial communities in the sediment of Jiaozhou Bay （China） using PCR-denaturing gradient gel electrophoresis （DGGE）. Sediment samples were collected from 10 different sites in May, August, and November 2008 and in February 2009. There was significant temporal variation in bacterial community composition at all sites. However, the spatial variation was very small. The DGGE analyses of bacterial communities were used to divide the 10 stations into three types. Canonical correspondence analysis （CCA） revealed that the changes in bacterial communities were driven by sediment properties. Sequence analysis of DGGE band-derived 16S rRNA gene fragments revealed that the dominant bacterial groups in the sediment were of the classes ~,-proteobacteria and ~3-proteobacteria and phyla Bacteroidetes and Nitrospirae. Our results provide considerable insight into the bacterial community structure in Jiaozhou Bay, China.

Development of a novel modified EGSB reactor for municipal sewage treatment at ambient temperatures

A novel modified expanded granular sludge bed(EGSBm) reactor was developed for anaerobic treatment of municipal sewage with mixed liquid recirculation instead of effluent recirculation commonly adopted by a conventional EGSB(EGSBc) reactor.Performances of these two reactors were compared in treating municipal sewage at ambient temperatures ranging from 8 to 26 ℃.At an upflow liquid velocity(Vup) of 10.3 m/h,the mean concentrations of filtrated COD(CODfilt) and COD of the EGSBm effluent were determined to be 59.4 and 95.9 mg/L,respectively,which were significantly lower than those of the EGSBc effluent operated under identical experimental conditions.When the organic loading rate was suddenly increased from 1.2 to 7.2 kg COD/(m3·d),the EGSBm regained the removal efficiency of previous operation phase in 10 d.Hydrodynamic characteristics of the reactors were compared using the residence time distribution(RTD) model.It was found that the treatment efficiency of EGSBm kept increasing as the Vup increased.The polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis(PCR-DGGE) technique was used to analyze the microbial diversity in EGSBm.Fingerprinting pattern indicated that some species in the inoculating sludge were still reserved in the granular sludge of EGSBm,moreover,several new species occurred.

Effect of Different Bacterial-Feeding Nematode Species on Soil Bacterial Numbers,Activity,and Community Composition

The effects of bacterial-feeding nematodes on bacterial number, activity, and community composition were studied through a microcosm experiment using sterilized soil inoculated with soil bacteria （soil suspension） and with bacteria and three species of bacterial-feeding nematodes （ Cephalobus persegnis, Protorhabditis filiformis, and Caenorhabditis elegans）. Catalyzed reporter deposition-fluorescence in situ hybridization, CO2 evolution, and denaturing gradient gel electrophoresis （DGGE） of PCR ampli- fied 16S rRNA gene fragments were used to investigate bacterial numbers, antivity, and community composition, respectively. Our results showed that bacterial numbers and activity significantly increased in the presence of bacterial-feeding nematodes, which indicated that bacterial-feeding nematodes had a significant positive effect on soil bacteria. The different nematode species had different effects on bacterial numbers and activity. C. persegnis and P. filiformis, isolated from native soil, increased the bacterial number and activity more than C. elegans. The DGGE analysis results showed that dominant bacterial species significantly differed among the treatments, which suggested that bacterial-feeding nematode species modified the bacterial community composition in soil. Further gene sequence analysis results showed that the dominant bacterial species in this study were gram-negative bacteria. Given the completely same conditions except nematode species, the varied selective feeding behavior of different nematode species was the most likely reason for the altered bacterial community composition. Overall, the alteration of bacterial numbers, activity and community composition resulting from the bacterial-feeding nematodes may ult!mately affect soil ecological functioning and processes.