用19个生化基因位点研究普通级Z:ZCLA长爪沙鼠的遗传多样性

目的调查Z:ZCLA长爪沙鼠原种群普通级长爪沙鼠的遗传多样性。方法用本实验室自行建立的长爪沙鼠19个生化基因位点的乙酸纤维素膜电泳技术并结合基本群体遗传学指标研究了普通级Z:ZCLA长爪沙鼠100个家系的遗传多态性。结果Z:ZCLA长爪沙鼠在Es-1、Car-2、Hbb、Gpi-1、Cs-1、Ce-2I、dh-l、Mod-1呈单态,在Es-2、Es-3、Es-4、Es-6、Es-8、Es-9、Es-10、pd-1、gm-1、Trf、Akp-1个位点上呈现多态性,等位基因从2~4个不等,平均等位基因数3.0,平均杂合度0.512,平均多态信息量0.455。结论提示目前本群遗传多样性水平处于中度多态。     

荒漠草原人工柠条林对冠下草本植物群落的保育作用

以宁夏盐池县荒漠草原人工柠条（Caragana intermedia）林为研究对象,分别选取柠条林冠下东侧（SE）,冠下西侧（SW）及带间（Gap）为研究样地,从群落水平探讨柠条对冠下草本植物群落结构、物种多样性及功能群分布的影响。结果表明：（1）在3种微生境中均鉴定出12种植物,SW以蒙古冰草为优势种,SE以蒙古冰草和中亚白草为优势种,Gap则以蒙古冰草和牛枝子为优势种。（2）与Gap相比,SW和SE植物群落的平均高度分别增加了41.06%和81.75%,地上生物量分别增加了40.88%和38.73%。SW和SE中,禾本科植物地上生物量分别占地上总生物量的67.10%和58.40%,显著高于Gap （P<0.05）。（3）柠条冠层效应使得草本植物的物种丰富度指数增加,但Shannon-Winner指数、Simpson指数和Pielou指数显著差异（P>0.05）,变化范围分别为1.620-1.756、0.701-0.730和0.775-0.878。（4）冗余分析表明：土壤温度、空气相对湿度及土壤有机碳是影响草本植物物种多样性及生物量的主要因子,解释量分别为42.70%,11.70%和8.80%。研究表明,柠条对冠下草本植物群落尤其是禾本科植物具有一定的保育作用,该效应的产生主要是由于柠条冠下微气候及土壤环境因子的改善为草本植物的生长发育提供了有利条件。柠条对草本植物的保育作用对荒漠草原生态环境的保护与恢复具有重要意义。     

丹参内生拮抗细菌DS-R5对丹参根际和根表土壤细菌群落结构的影响CSCD

目的 探究生防细菌DS-R5施入丹参植株后根际和根表土壤细菌群落组成及多样性变化。方法 向丹参植株根部施入生防细菌DS-R5,以未施用细菌为对照组,分别采集根际和根表土壤样品提取总DNA,扩增样品总DNA的V3-V4区,采用Illumina MiSeq测序平台对PCR扩增产物进行双端测序分析,利用生物信息学分析解析丹参植株根际土壤和根表土壤细菌群落结构组成及多样性。结果 菌株DS-R5处理后增加了根际土壤细菌群落的多样性和丰度,降低了根表土壤细菌群落的多样性和丰度;高通量测序得到的根际和根表土壤的有效序列数量和OTU数量相比对照组均有所下降,根际土壤处理样品中微生物种类最丰富,根表土壤处理样品中微生物种类最少,根际土壤处理样品与根际土壤对照物种种类更接近;在门水平上,根际土壤处理样品相比对照变形菌门丰度下降,酸杆菌门丰度升高,根表土壤处理样品相比对照变形菌门和酸杆菌门丰度均升高,放线菌门丰度降低;在属水平上,根际土壤处理样品中鞘氨醇单胞菌属、芽胞杆菌属、慢生根瘤菌属相比根际土壤对照占比均有升高,根表土壤处理样品相比对照黄杆菌属和伯克菌属丰度下降,而土壤中的优势菌属根瘤菌属和芽胞杆菌属丰度升高。结论 丹参植株施用生防细菌DS-R5后,改变了根际土壤和根表土壤中微生物群落结构和多样性。     

Genome sequencing and comparative analysis of three Chlamydia pecorum strains associated with different pathogenic outcomes

Background

Chlamydia pecorum is the causative agent of a number of acute diseases, but most often causes persistent, subclinical infection in ruminants, swine and birds. In this study, the genome sequences of three C. pecorum strains isolated from the faeces of a sheep with inapparent enteric infection (strain W73), from the synovial fluid of a sheep with polyarthritis (strain P787) and from a cervical swab taken from a cow with metritis (strain PV3056/3) were determined using Illumina/Solexa and Roche 454 genome sequencing.

Results

Gene order and synteny was almost identical between C. pecorum strains and C. psittaci. Differences between C. pecorum and other chlamydiae occurred at a number of loci, including the plasticity zone, which contained a MAC/perforin domain protein, two copies of a >3400 amino acid putative cytotoxin gene and four (PV3056/3) or five (P787 and W73) genes encoding phospholipase D. Chlamydia pecorum contains an almost intact tryptophan biosynthesis operon encoding trpABCDFR and has the ability to sequester kynurenine from its host, however it lacks the genes folA, folKP and folB required for folate metabolism found in other chlamydiae. A total of 15 polymorphic membrane proteins were identified, belonging to six pmp families. Strains possess an intact type III secretion system composed of 18 structural genes and accessory proteins, however a number of putative inc effector proteins widely distributed in chlamydiae are absent from C. pecorum. Two genes encoding the hypothetical protein ORF663 and IncA contain variable numbers of repeat sequences that could be associated with persistence of infection.

Conclusions

Genome sequencing of three C. pecorum strains, originating from animals with different disease manifestations, has identified differences in ORF663 and pseudogene content between strains and has identified genes and metabolic traits that may influence intracellular survival, pathogenicity and evasion of the host immune system.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-23) contains supplementary material, which is available to authorized users.     

海藻酸微囊替代DMSO和FBS的STO细胞冷冻保存研究

目的:改进现有的细胞冷冻保存方法,建立一个不含二甲基亚砜(DMSO)和血清(FBS)的高效冷冻保存方法,为细胞治疗等临床实践提供优质细胞.方法:海藻酸微囊包埋鼠胚成纤维细胞(STO细胞)后用不含DMSO和FBS的冷冻保存液进行冷冻保存.设四个对照组:添加10％DMSO和20％FBS的组、仅添加10％DMSO的组、仅添加20％FBS、DMSO和FBS均不添加组.在冷冻前后对各实验组细胞用台盼兰染色,进行细胞计数,计算细胞存活率,同时利用溴乙锭的二聚物(EthD)、钙黄绿素-AM(Calcein-AM)进行染色观察细胞的形态,且进一步验证细胞存活率;解冻复苏后用MTT法评估细胞的增殖速度和生长活力.结果:冷冻保存30天后对各组的细胞数量、细胞存活率、细胞形态和解冻复苏后细胞的生长活力进行比较发现,海藻酸微囊包埋冷冻组的细胞数、细胞存活率、细胞形态和生长活力均与添加DMSO和FBS的组之间无显著性差异,而与其它三个对照组呈显著性差异.结论:使用海藻酸微囊替代DMSO和FBS保存STO细胞,能有效的维持细胞形态、数量、存活率,同时不影响细胞的生长活力,从而建立了一个不含DMSO和FBS的高效冷冻保存方法.     

The macroeconomic consequences of renouncing to universal access to antiretroviral treatment for HIV in Africa: a micro-simulation model

Aim

Previous economic literature on the cost-effectiveness of antiretroviral treatment (ART) programs has been mainly focused on the microeconomic consequences of alternative use of resources devoted to the fight against the HIV pandemic. We rather aim at forecasting the consequences of alternative scenarios for the macroeconomic performance of countries.

Methods

We used a micro-simulation model based on individuals aged 15–49 selected from nationally representative surveys (DHS for Cameroon, Tanzania and Swaziland) to compare alternative scenarios : 1-freezing of ART programs to current levels of access, 2- universal access (scaling up to 100% coverage by 2015, with two variants defining ART eligibility according to previous or current WHO guidelines). We introduced an “artificial” ageing process by programming methods. Individuals could evolve through different health states: HIV negative, HIV positive (with different stages of the syndrome). Scenarios of ART procurement determine this dynamics. The macroeconomic impact is obtained using sample weights that take into account the resulting age-structure of the population in each scenario and modeling of the consequences on total growth of the economy.

Results

Increased levels of ART coverage result in decreasing HIV incidence and related mortality. Universal access to ART has a positive impact on workers'' productivity; the evaluations performed for Swaziland and Cameroon show that universal access would imply net cost-savings at the scale of the society, when the full macroeconomic consequences are introduced in the calculations. In Tanzania, ART access programs imply a net cost for the economy, but 70% of costs are covered by GDP gains at the 2034 horizon, even in the extended coverage option promoted by WHO guidelines initiating ART at levels of 350 cc/mm³ CD4 cell counts.

Conclusion

Universal Access ART scaling-up strategies, which are more costly in the short term, remain the best economic choice in the long term. Renouncing or significantly delaying the achievement of this goal, due to “legitimate” short term budgetary constraints would be a misguided choice.     

PKC-induced stiffening of hyaluronan/CD44 linkage; local force measurements on glioma cells

Interaction of cells with hyaluronan (HA) rich extracellular matrix involves the membrane receptor CD44. HA-CD44 interactions are particularly important in the development of glioma pathogenesis for its implication in tumor cells spreading. Highly motile states rely on the spaciotemporal regulation of HA-CD44 interactions occurring in specific cytoskeletal-supported membrane organization such as microvilli or the leading edge observed in migrating cell. We used AFM-based force measurement to probe the HA-CD44 interaction at localized regions at the surface of living glioma cells expressing high level of the CD44 standard isoform. We show that unstimulated cells interact with HA over their entire surfaces and are highly deformable when force is exerted on individual HA molecules bound to membrane CD44 receptors. Conversely, in PKC-activated cells the probed interactions are concentrated at the leading edge of the cells with reduced membrane deformability. Taken together, our results show that PKC-enhanced motility in glioma cells is associated with a redistribution of CD44 receptors at the leading edges concomitant with a stiffer anchoring of CD44 to the cell surface involving the actin cytoskeleton.     

H-FABP基因的多态性和营养因素对猪肉质的影响

遗传和营养因素都能影响猪肉的品质。但是, 到目前为止同时研究遗传和营养因素对肉质影响的报道很少。在本研究中, 136头PIC5系杂交猪, 体重65 kg, 被随机分成4组, 各组分别给予不同日粮。在饲养35 d、体重大约90 kg时统一屠宰并且进行肉质测定、H-FABP基因分型及其与肉质性状的关联分析。结果表明: (1)所采用的3种日粮对肉色、屠宰后24 h的pH、肌内脂肪和肌肉蛋白含量有极显著的影响; (2)H-FABP基因型对肌内脂肪和肌肉蛋白含量存在极显著的影响; (3)H-FABP基因多态性和营养因素的交互作用对pH 和肌内脂肪含量均有显著的影响, 对照组的AA基因型具有最高pH值, 高维生素E组的AA基因型具有最高肌内脂肪值。实验结果提示在关于猪肉质的育种和生产过程中应该同时考虑营养因素和遗传因素。     

Reliability of EMG spectral parameters in repeated measurements of back muscle fatigue.

The change in median frequency of the power spectrum of the electromyographic (EMG) signal may be used as a measure of muscle fatigue. The reliability of the median frequency parameters was investigated for EMG-recording sites at L1 and L5 right and left on the erector spinae. The reliability of subjective fatigue ratings of the back muscles (Borg CR-10 scale) and of maximal trunk extension torque (MVC) was also investigated. Eleven subjects with healthy backs performed a 45-s isometric trunk extension at 80% of MVC twice a day, on three different days. Two-factor analysis of variance was made to obtain the different variances from which the standard error of measurement (SEM) and the intra class correlation coefficient (ICC) were calculated. The SEM within-day was somewhat lower than that between-days. Both were about the same at all four electrode sites. The 95% confidence interval for the studied variables was for the initial median frequency +/- 10 Hz, for the slope +/- 0.4-0.5%/s, for the MVC +/- 36 Nm and for the Borg ratings +/- 1.6. We conclude that, with the presently used method, changes or differences within these limits should be regarded as normal variability. The slope may be of limited value because of its large variability. Whether the low intraclass correlation coefficient for the EMG parameters in the presently studied test group implies a low potential in discriminating subjects with back pain can not be decisively concluded.     

Diversity, composition, and geographical distribution of microbial communities in California salt marsh sediments

The Pacific Estuarine Ecosystem Indicators Research Consortium seeks to develop bioindicators of toxicant-induced stress and bioavailability for wetland biota. Within this framework, the effects of environmental and pollutant variables on microbial communities were studied at different spatial scales over a 2-year period. Six salt marshes along the California coastline were characterized using phospholipid fatty acid (PLFA) analysis and terminal restriction fragment length polymorphism (TRFLP) analysis. Additionally, 27 metals, six currently used pesticides, total polychlorinated biphenyls and polycyclic aromatic hydrocarbons, chlordanes, nonachlors, dichlorodiphenyldichloroethane, and dichlorodiphenyldichloroethylene were analyzed. Sampling was performed over large (between salt marshes), medium (stations within a marsh), and small (different channel depths) spatial scales. Regression and ordination analysis suggested that the spatial variation in microbial communities exceeded the variation attributable to pollutants. PLFA analysis and TRFLP canonical correspondence analysis (CCA) explained 74 and 43% of the variation, respectively, and both methods attributed 34% of the variation to tidal cycles, marsh, year, and latitude. After accounting for spatial variation using partial CCA, we found that metals had a greater effect on microbial community composition than organic pollutants had. Organic carbon and nitrogen contents were positively correlated with PLFA biomass, whereas total metal concentrations were positively correlated with biomass and diversity. Higher concentrations of heavy metals were negatively correlated with branched PLFAs and positively correlated with methyl- and cyclo-substituted PLFAs. The strong relationships observed between pollutant concentrations and some of the microbial indicators indicated the potential for using microbial community analyses in assessments of the ecosystem health of salt marshes.