Continental Refugium in the Mongolian Plateau during Quaternary Glacial Oscillations: Phylogeography and Niche Modelling of the Endemic Desert Hamster,Phodopus roborovskii

The Mongolian Plateau (MP), which is situated in the interior of Asia and possesses a typical continental climate, experienced harsh climatic conditions during the Quaternary glacial fluctuations. Although these events likely had huge impacts on the local animal populations, the current effects have hardly been explored. To investigate whether the MP supported a refugium along an oceanic-continental gradient (ROCG), and whether this refugium was glacial or interglacial, we investigated the demographic and phylogeographic history of an endemic mammal species, the desert hamster Phodopus roborovskii. We reconstructed the demographic variation, the phylogeographic diffusion, and modelled the potential habitat during historical periods. The genetic diversity in the MP was the highest among all the localities, and the MP was a suitable habitat throughout the modelled historical periods. A phylogeographic diffusion analysis emphasized the importance of the MP as the centre of origin, preservation and spread for P. roborovskii. The homogeneous landscape provided the opportunity for a wide gene flow, which resulted in low resolution of the phylogenetic relationships. Moreover, P. roborovskii was favoured by the interglacial condition, with both its demographical and geographical ranges expanded within the interglacial periods. The range variation from the Last Glacial Maximum to the current condition reflects a distinct longitudinal shift, while both ranges largely contracted from that of the Last Interglacial. Our results support that the MP served as a refugium and spread centre for P. roborovskii during the Quaternary climate fluctuations. The interglacial expansion and the longitudinal shifts highlighted the important effects of precipitations on the distribution range of species adapted to arid and semi-arid during glacial oscillations.     

新疆艾比湖沉积物中免培养放线菌的多样性北大核心CSCD

【目的】采用免培养的方法研究新疆艾比湖湖底沉积物放线菌组成及多样性。【方法】采集并混合5份艾比湖湖底沉积物样本,并提取其总DNA,采用放线菌通用引物对其16S r RNA基因序列进行Touchdown PCR,构建放线菌16S r RNA基因文库。蓝白斑筛选后随机挑选白色克隆分析,利用限制性内切酶HhaⅠ进行酶切分型,挑选具有独特限制性片段差异的阳性克隆进行测序分析。序列经Chimera Check检测,BLAST同源比对及构建16S r RNA基因序列系统发育树。【结果】随机挑选192个白色克隆,其中166个为阳性克隆,选取51个具有独特限制性片段差异的克隆进行序列分析。测序结果进行比对以及Chimera Check检测后,共获得36个可操作单元(Operational Taxonomic Units,OTUs),Gen Bank注册号为KR182090-KR182131。文库覆盖度结果表明克隆文库涵盖了本环境中90.4%的放线菌类群。聚类结果显示,艾比湖湖底沉积物中放线菌分为2个类群,第1个类群属于放线菌门(Actinobacteria),放线菌纲(Actinobacteria)中的放线菌目(Actinomycetales)、丙酸杆菌目(Propionibacteriales)、微球菌目(Micrococcales)和棒杆菌目(Corynebacteriales)4个目,该类群占克隆文库18.1%;另外1个类群属于Unclassified Actinobacteria的类群,分为3个不同的group,占整个克隆文库的81.9%。【结论】新疆艾比湖湖底沉积物中存在多种未知的放线菌类群。     

乳酸链球菌素对瘤胃体外发酵、甲烷生成及功能菌群数量的影响北大核心CSCD

【目的】旨在通过体外静态模拟瘤胃发酵法研究乳酸链球菌素(NI)对瘤胃发酵、甲烷生成及功能菌群数量的影响。【方法】以不添加任何添加剂处理做阴性对照(NC),以莫能菌素(MON,5μmol/L)做阳性对照,试验组NI添加水平分别为3(NI-3)、9(NI-9)和27 mg/100 m L(NI-27),每个处理4个重复,分别于培养后的0、3、6、9、12、24 h测定产气量和甲烷产量。培养24 h后,采集发酵液样品,用于发酵参数和菌群数量的测定。【结果】与NC组相比,添加NI和MON均能显著降低产气量和甲烷产量(P<0.05);添加NI对pH值、干物质消失率(DMD)和有机物消失率(OMD)无显著影响(P>0.05);NI-9处理组与NC组相比氨态氮浓度显著降低(P<0.05),而NI-3和NI-27组氨氮浓度没有显著变化(P>0.05);相比而言,MON处理组DMD、OMD和氨氮浓度与NC组相比均显著降低(P<0.05),而pH值与其他各处理组相比没有差异(P>0.05);与NC组相比,NI各处理组和MON组乙酸浓度及乙丙比均显著降低(P<0.05),丙酸浓度显著提高(P<0.05)。功能菌方面,qPCR结果显示添加NI和MON对总菌和拟杆菌门数量均无显著影响(P>0.05);与NC相比,添加NI对原虫、甲烷菌、真菌和厚壁菌门数量均无显著影响(P>0.05),而MON组原虫、甲烷菌、真菌和厚壁菌门数量显著降低(P<0.05);NI和MON处理均显著提高了硫还原菌和C.aminophilum数量(P<0.05),但C.sticklandii数量不受影响(P>0.05)。【结论】添加适宜浓度的NI可降低瘤胃甲烷与氨的生成,但并不影响饲料消化,这种发酵模式的改变可能与瘤胃功能菌群数量与多样性的变化密切相关。     

Isovitexin Exerts Anti-Inflammatory and Anti-Oxidant Activities on Lipopolysaccharide-Induced Acute Lung Injury by Inhibiting MAPK and NF-κB and Activating HO-1/Nrf2 Pathways

Oxidative damage and inflammation are closely associated with the pathogenesis of acute lung injury (ALI). Thus, we explored the protective effect of isovitexin (IV), a glycosylflavonoid, in the context of ALI. To accomplish this, we created in vitro and in vivo models by respectively exposing macrophages to lipopolysaccharide (LPS) and using LPS to induce ALI in mice. In vitro, our results showed that IV treatment reduced LPS-induced pro-inflammatory cytokine secretion, iNOS and COX-2 expression and decreased the generation of ROS. Consistent findings were obtained in vivo. Additionally, IV inhibited H₂O₂-induced cytotoxicity and apoptosis. However, these effects were partially reversed following the use of an HO-1 inhibitor in vitro. Further studies revealed that IV significantly inhibited MAPK phosphorylation, reduced NF-κB nuclear translocation, and upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) expression in RAW 264.7 cells. In vivo, pretreatment with IV attenuated histopathological changes, infiltration of polymorphonuclear granulocytes and endothelial activation, decreased the expression of ICAM-1 and VCAM-1, reduced the levels of MPO and MDA, and increased the content of GSH and SOD in ALI. Furthermore, IV treatment effectively increased Nrf2 and HO-1 expression in lung tissues. Therefore, IV may offer a protective role against LPS-induced ALI by inhibiting MAPK and NF-κB and activating HO-1/Nrf2 pathways.     

Green synthesis of fluorescence carbon nanoparticles from yum and application in sensitive and selective detection of ATP

Fluorescent carbon nanoparticles (CPs), a fascinating class of recently discovered nanocarbons, have been widely known as some of the most promising sensing probes in biological or chemical analysis. In this study, we demonstrate a green synthetic methodology for generating water‐soluble CPs with a quantum yield of approximately 24% via a simple heating process using yum mucilage as a carbon source. The prepared carbon nanoparticles with an ~10 nm size possessed excellent fluorescence properties, and the fluorescence of the CPs was strongly quenched by Fe³⁺, and recovered by adenosine triphosphate (ATP), thus, an ‘off’ and ‘on’ system can be easily established. This ‘CPs‐Fe³⁺‐ATP’ strategy was sensitive and selective at detecting ATP with the linear range of 0.5 µmol L^?1 to 50 µmol L^?1 and with a detection limit of 0.48 µmol L^?1. Copyright © 2015 John Wiley & Sons, Ltd.