Diversity of endophytic bacteria and fungi in seeds of Elymus nutans growing in four locations of Qinghai Tibet Plateau,China

Plant and Soil - Seeds are involved in the transmission of microorganisms from one plant generation to the next, acting as initial inoculum for the plant microbiome, therefore provide a key source...     

CdS nanoparticles‐ enhanced chemiluminescence and determination of baicalin in pharmaceutical preparations

CdS nanoparticles (CdS NPs) of different sizes were synthesized by the citrate reduction method. It was found that CdS NPs could enhance the chemiluminescence (CL) of the luminol‐potassium ferricyanide system and baicalin could inhibit CdS NPs‐enhanced luminol‐potassium ferricyanide CL signals in alkaline solution. Based on this inhibition, a flow‐injection CL method was established for determination of baicalin in pharmaceutical preparations and human urine samples. Under optimized conditions, the linear range for determination of baicalin was 5.0 x 10^?6 to 1.0 x 10^?3 g/L. The detection limit at a signal‐to‐noise ratio of 3 was 1.7 x 10 ^?6 g/L. CL spectra, UV‐visible spectra and transmission electron microscopy (TEM) were used to investigate the CL mechanism. The method described is simple, selective and obviates the need of extensive sample pretreatment. Copyright © 2012 John Wiley & Sons, Ltd.     

中国西藏地区刺齿属一新种(弹尾目:长科)(英文)

本文记述刺齿属一新种──西藏刺齿Homidiatibetensissp．nov．该种有些特征与H．heugsanicaLeeetPark,1984相似,但第1,3,4腹节毛序,下唇基部毛式和上唇无乳突可与后者区分。     

Qualitative and Quantitative PCR Methods for Event-specific Detection of Genetically Modified Cotton Mon1445 and Mon531

Based on the DNA sequences of the junctions between recombinant and cotton genomic DNA of the two genetically modified (GM) cotton varieties, herbicide-tolerance Mon1445 and insect-resistant Mon531, event-specific primers and probes for qualitative and quantitative PCR detection for both GM cotton varieties were designed, and corresponding detection methods were developed. In qualitative PCR detection, the simplex and multiplex PCR detection systems were established and employed to identify Mon1445 and Mon531 from other GM cottons and crops. The limits of detection (LODs) of the simplex PCR were 0.05% for both Mon1445 and Mon531 using 100 ng DNA templates in one reaction, and the LOD of multiplex PCR analysis was 0.1%. For further quantitative detection using TaqMan real-time PCR systems for Mon1445 and Mon531, one plasmid pMD-ECS, used as reference molecule was constructed, which contained the quantitative amplified fragments of Mon1445, Mon531, and cotton endogenous reference gene. The limits of quantification (LOQs) of Mon1445 and Mon531 event-specific PCR systems using plasmid pMD-ECS as reference molecule were 10 copies, and the quantification range was from 0.03 to 100% in 100 ng of the DNA template for one reaction. Thereafter, five mixed cotton samples containing 0, 0.5, 0.9, 3 and 5% Mon1445 or Mon531 were quantified using established real-time PCR systems to evaluate the accuracy and precision of the developed real-time PCR detection systems. The accuracy expressed as bias varied from 1.33 to 8.89% for tested Mon1445 cotton samples, and from 2.67 to 6.80% for Mon531. The precision expressed as relative standard deviations (RSD) were different from 1.13 to 30.00% for Mon1445 cotton, and from 1.27 to 24.68% for Mon531. The range of RSD was similar to other laboratory results (25%). Concluded from above results, we believed that the established event-specific qualitative and quantitative PCR systems for Mon1445 and Mon531 in this study are acceptable and suitable for GM cotton identification and quantification.     

Protective immune response of bacterially-derived recombinant FaeG in piglets

FaeG is the key factor in the infection process of K88ad enterotoxigenic Escherichia coli(ETEC) fimbrial adhesin. In an attempt to determine the possibility of expressing recombinant FaeG with immunogenicity for a new safe and high-production vaccine in E. coli, we constructed the recombinant strain, BL21 (DE3+K88), which harbors an expression vector with a DNA fragment of faeG, without a signal peptide. Results of 15% SDS-polyacrylamide slab gel analysis showed that FaeG can be stably over-expressed in BL21 (DE3+K88) as inclusion bodies without FaeE. Immunoglobulin G (IgG) and M (IgM) responses in pregnant pigs, with boost injections of the purified recombinant FaeG, were detected 4 weeks later in the sera and colostrum. An in vitro villius-adhesion assay verified that the elicited antibodies in the sera of vaccinated pigs were capable of preventing the adhesion of K88ad ETEC to porcine intestinal receptors. The protective effect on the mortality rates of suckling piglets born to vaccinated mothers was also observed one week after oral challenge with the virulent ETEC strain, C83907 (K88ad, CT+, ST+). The results of this study proved that the adhesin of proteinaceous bacterial fimbriae or pili could be overexpressed in engineered E. coli strains, with protective immune responses to the pathogen.     

Chemiluminescence determination of fluoroquinolone antibiotics using a soluble manganese (IV)-sulphite system.

The reaction of soluble manganese (IV) with sulphite in acidic condition was found to elicit weak chemiluminescence (CL). The CL signal was remarkably enhanced in the presence of three fluoroquinolones, viz. norfloxacin, ofloxacin and ciprofloxacin. Based on these observations, a new flow-injection CL method was developed for the determination of these fluoroquinolones. The method allows determination in the range 5.0 x 10(-8)-1.0 x 10(-6) mol/L for norfloxacin, 1.0 x 10(-7)-8.0 x 10(-6) mol/L for ofloxacin and 1.0 x 10(-7)-3.0 x 10(-5) mol/L for ciprofloxacin, with detection limits of 3 x 10(-8) mol/L, 5 x 10(-8) mol/L and 3 x 10(-8) mol/L, respectively. The method was applied to the determination of fluoroquinolones in pharmaceutical preparations.     

NADPH oxidase-mediated generation of reactive oxygen species: A new mechanism for X-ray-induced HeLa cell death

Oxidative damage is an important mechanism in X-ray-induced cell death. Radiolysis of water molecules is a source of reactive oxygen species (ROS) that contribute to X-ray-induced cell death. In this study, we showed by ROS detection and a cell survival assay that NADPH oxidase has a very important role in X-ray-induced cell death. Under X-ray irradiation, the upregulation of the expression of NADPH oxidase membrane subunit gp91^phox was dose-dependent. Meanwhile, the cytoplasmic subunit p47^phox was translocated to the cell membrane and localized with p22^phox and gp91^phox to form reactive NADPH oxidase. Our data suggest, for the first time, that NADPH oxidase-mediated generation of ROS is an important contributor to X-ray-induced cell death. This suggests a new target for combined gene transfer and radiotherapy.     

九华山土壤跳虫的生态分布

在九华山4种生境中共获土壤跳虫5904个,分隶10科52属,等跳科有14属,数量占各科总数72.09%,其中以符跳属个体数占绝对优势,不同群落组成成分及各项指标差异显著,混交林土层中种、数量丰富,若以土层和Aoo层总和计算,则有高海拔生境各落比低海拔多的趋势,灌丛草甸土壤跳虫群落的H和E值高而且季节变化不大,秋冬季节各群落种、数都有增加,而以山上两个群落Aoo层增加更多,表聚现象十分突出。