A rapid real-time recombinase polymerase amplification assay for diagnosis of acute hepatopancreatic necrosis disease in shrimp

Acute hepatopancreatic necrosis disease(AHPND)is an emerging disease in the shrimp farming industry with a high mortality rate that causes serious economic loss...     

核因子E2相关因子2在运动改善非酒精性脂肪性肝病中的作用

核因子E2相关因子2 (nuclear factor erythroid 2-related factor 2,Nrf2)信号通路在维持心血管疾病、神经系统退行性疾病以及慢性代谢性疾病中的细胞稳态方面起关键作用。研究表明,以氧化应激、炎症和线粒体功能失调为特征的慢性疾病可通过增加Nrf2表达来恢复机体氧化还原状态,治疗或预防疾病。非酒精性脂肪性肝病（nonalcoholic fatty liver disease,NAFLD）是一种由除酒精以外的其他多种因素导致的以肝脏脂肪变性为特征的慢性代谢性肝脏疾病,其患病率近年来在全球范围内逐渐增加。运动是防治NAFLD的有效手段,可通过运动方式、运动强度、运动环境和运动疲劳等因素影响Nrf2信号通路。本文通过阐述Nrf2信号通路的激活、其调控抗氧化的相关机制以及运动对Nrf2信号通路的影响,以NAFLD的发病机制为基础,探讨运动、Nrf2和NAFLD之间的关系,综述Nrf2在运动改善NAFLD中的作用及相关机制。为运动改善NAFLD的分子机制研究提供理论参考依据。     

猪圆环病毒2型流行株的分离及其感染性克隆的构建

【目的】通过分离一株猪圆环病毒2型(PCV2)流行毒株,并构建其感染性克隆,为研究PCV2基因功能提供操作平台。【方法】通过PCR方法,从疑似患断奶仔猪多系统衰竭综合症(PMWS)的仔猪淋巴结中鉴定为猪圆环病毒(Porcine circovirus,PCV)2型阳性。把阳性病料接种PK-15细胞传代培养,在培养物中扩增出PCV2的全基因序列。对扩增出的全序列进行序列测定,并与GenBank中公布的5株广东PCV2分离株(GD-pz、GD-gj、GD-jm、GD-ss和GD-sz)进行同源性分析。通过EcoRⅠ和SalⅠ将PCV2全基因组序列克隆进pUC18载体中,获得含PCV2 GD-zq株全基因组单拷贝的重组质粒pPCV2-GD-zq,再通过SalⅠ和HindⅢ把另一个全长拷贝克隆进pPCV2-GD-zq质粒中,使PCV2 GD-zq株基因组DNA以头尾相接的双重复方式克隆进pUC18载体中,获得重组质粒pPCV2-2GD-zq。将pPCV2-2GD-zq DNA纯化和定量后转染PK-15细胞,拯救PCV2 GD-zq病毒。【结果】从PMWS感染的猪淋巴结中分离到了一株PCV2,命名为GD-zq株;序列分析结果显示,GD-zq株全基因组为1 767 bp,与GenBank中公布的5株广东PCV2分离株ORF1核苷酸一致性为97.1%-99.7%,编码氨基酸一致性为98.7%-100%;ORF2核苷酸一致性为93.2%-99.6%,编码氨基酸一致性为92.3%-99.1%;全基因一致性为96.0%-99.6%。pPCV2-2GD-zq质粒转染PK-15细胞后,其通过间接免疫荧光实验(IFA)能从转染细胞及其传代细胞中,检测到拯救出的病毒。【结论】分离了一株PCV2广东株GD-zq,成功构建了PCV2 GD-zq株的感染性克隆。     

城市景观生态风险评估框架与实践——以北京天坛地区为例

当前,城市景观生态风险研究缺少科学合理、方便实用的评估框架。作者基于景观生态风险评估基本范式,明确了城市景观生态服务价值的测算方法,分析了引起生态损害的自然因素和人类活动因素,形成了城市景观生态风险评估的技术框架和参数体系;继而以北京天坛地区为研究区,开展了典型城市景观生态风险的定量评估。结果表明：（1）天坛地区景观生态价值总量约为2.41亿元。区域的历史文化价值最高,教育和美学景观价值紧随其后。（2）城市景观生态受损概率呈现"北高南低"的空间分布格局。生态受损概率的高值区面积占整个区域总面积的22.2%,主要分布在珠市口、磁器口和崇文门附近区域。（3）城市景观生态风险呈现"北低南高"的空间分布格局。高风险区主要分布在天坛公园内的文物建筑周边。本研究提供了一个可参考的城市景观生态风险评估应用框架,对生态风险评估中的不确定性进行了讨论,研究针对天坛案例区的具体结论有助于城市管理者避免潜在的风险。     

Regulation of progesterone during follicular development by FSH and LH in sheep

Progesterone (P4) can participate in the development of female mammalian antral follicles through nuclear receptor (PGR). In this experiment, the differences of P4 synthesis and PGR expression in different developmental stages of sheep antral follicles (large > 5mm, medium 2-5mm, small < 2mm) were detected by enzyme-linked immunosorbent assay, immunohistochemistry, qRT-PCR and Western blotting. Secondly, sheep follicular granulosa cells were cultured in vitro. The effects of different concentrations of FSH and LH on P4 synthesis and PGR expression were studied. The results showed that acute steroid regulatory protein (StAR), cholesterol side chain lyase (P450scc) and 3β Hydroxysteroid dehydrogenase (3β-HSD) and PGR were expressed in antral follicles, and with the development of antral follicles in sheep, StAR, P450scc and the expression of 3β-HSD and PGR increased significantly. In vitro experiments showed that FSH and LH alone or together treatment could regulate P4 secretion and PGR expression in sheep follicular granulosa cells to varying degrees, hint P4 and PGR by FSH and LH, and LH was the main factor. Our results supplement the effects of FSH and LH on the regulation of P4 synthesis during follicular development, which provides new data for further study of steroid synthesis and function in follicular development.     

Electron acceptors for anaerobic oxidation of methane drive microbial community structure and diversity in mud volcanoes

Mud volcanoes (MVs) emit globally significant quantities of methane into the atmosphere, however, methane cycling in such environments is not yet fully understood, as the roles of microbes and their associated biogeochemical processes have been largely overlooked. Here, we used data from high‐throughput sequencing of microbial 16S rRNA gene amplicons from six MVs in the Junggar Basin in northwest China to quantify patterns of diversity and characterize the community structure of archaea and bacteria. We found anaerobic methanotrophs and diverse sulfate‐ and iron‐reducing microbes in all of the samples, and the diversity of both archaeal and bacterial communities was strongly linked to the concentrations of sulfate, iron and nitrate, which could act as electron acceptors in anaerobic oxidation of methane (AOM). The impacts of sulfate/iron/nitrate on AOM in the MVs were verified by microcosm experiments. Further, two representative MVs were selected to explore the microbial interactions based on phylogenetic molecular ecological networks. The sites showed distinct network structures, key species and microbial interactions, with more complex and numerous linkages between methane‐cycling microbes and their partners being observed in the iron/sulfate‐rich MV. These findings suggest that electron acceptors are important factors driving the structure of microbial communities in these methane‐rich environments.     

睡莲科的系统发育:核糖体DNA ITS区序列证据

以金鱼藻Ceratophyllum demersum为外类群,使用PAUP4.0b4A软件对睡莲科Nymphaeaceae植物7属11个代表种的ITS区序列进行了系统发育分析。采用最大简约法分析获得了3个最简约树,步长为1125,一致性指数(CI)和维持性指数(RI)值分别为0.7618和0.7214。利用3个最简约树获取严格一致树。结果表明:(1)莲属Nelumbo位于系统树的基部,自展支持率为100%,可从睡莲科中独立出来成立莲科Nelumbonaceae和莲目Nelumbonales;(2)萍蓬草属Nuphar是一单系类群,位于分支Ⅱ的基部,并和睡莲科其他属(不包括莲属)植物聚在一起构成姐妹群,故萍蓬草属仍应置于睡莲科中;(3)水盾草属Cabomba和莼菜属Brasenia聚成一小支并构成姐妹群,自展支持率为99%,说明这两属之间亲缘关系较近;(4)睡莲属和芡实属Euryale、王莲属Victoria聚成一小支并构成姐妹群,自展支持率为94%,说明三者亲缘关系较近,仍应置于睡莲科中。     

MyD88-independent activation of a novel actin-Cdc42/Rac pathway is required for Toll-like receptor-stimulated phagocytosis

Phagocytosis and subsequent degradation of pathogens by macrophages play a pivotal role in host innate immune responses to microbial infection. Recent studies have shown that Toll-like receptors （TLRs） play an important role in promoting the clearance of bacteria by up-regulating the phagocytic activity of macrophages. However, information regarding the signaling mechanism of TLR-mediated phagocytosis is still limited. Here, we provide evidence that the stimulation of TLR4 with LPS leads to activation of multiple signaling pathways including MAP kinases, phosphatidylinositide 3-kinase （PI3K）, and small GTPases in the murine macrophage-like cell line RAW264.7. Specific inhibition of Cdc42/Rac or p38 MAP kinase, but not PI3K, reduced TLR4-induced phagocytosis of bacteria. Moreover, we have found that either inhibition of actin polymerization by cytochalasin D or the knockdown of actin by RNAi markedly reduced the activation of Cdc42 and Rac by LPS. TLR4-induced activation of Cdc42 and Rac appears to be independent of MyD88. Taken together, our results described a novel actin-Cdc42/Rac pathway through which TLRs can specifically provoke phagocytosis.