酵母双杂交系统用于WSSV粘附蛋白VP37相关蛋白基因的研究

为研究WSSV的粘附蛋白VP37相关蛋白的基因，应用酵母双杂交系统Ⅲ筛选中国明对虾(Fenneropenaeus chinensis)鳃细胞全长cDNA文库。构建VP37基因的重组载体PGBKT7-VP37，把它转化酵母Y187后与含文库质粒的酵母AH109配合，在营养缺陷培养基上进行双杂交筛选。经过PCR鉴定确定了1个阳性克隆。测定该段cDNA序列并进行生物信息学分析，结果显示，此cDNA片段编码的蛋白与蛋白酶的同源性较高，该蛋白在WSSV识别并结合宿主的过程中所起的作用还有待于进一步研究。成功筛选了VP37相关蛋白的cDNA片段，为研究WSSV入侵以及感染致病的机制等方面提供了新线索。     

附着基的形状、粗糙度和颜色对仿刺参幼体附着的影响

在水温21℃～22℃下,将仿刺参（Apostichopus japonicus）耳状幼体放养在6个30 L的塑料水槽中,密度为303个.L-1,投喂盐藻（Dunaliella salina）和牟氏角毛藻（Chaetoceros müelleri）的混合液。培育至樽形幼体前,放入10 cm×10 cm的聚乙烯波纹板和聚乙烯平板;这些板表面光滑、粗糙（具沟,沟间距为500 um）和较粗糙（沟间距250 nm）;或贴上绿、黑、黄、红和蓝5种颜色的聚乙烯贴纸,以无贴纸的透明附着基为对照。结果表明,附着10 d后,波纹板上附着的仿刺参幼体数量比平板上高68.76%,差异极其显著（t=7.131〉2.804,df=23）;光滑附着基表面上仿刺参幼体的附着量分别比粗糙和较粗糙附着基高267.42%和32.34%,与粗糙附着基差异显著;红色和黑色附着基的幼体附着量比对照组高84.52%和37.49%,与对照组差异极显著,且随培育时间的延长促附着效果越明显。不同形状、粗糙度和颜色的附着基表面仿刺参幼体的附着率均随着时间的推移而下降,附着后5~6d时最甚。仿刺参刚刚开始附着1～2d未长出管足,附着5d时,大部分只长出1个管足,10d时,大部分生长出两个管足。     

The parasite–host interface in the zonetail butterfly ray,Gymnura zonura (Bleeker), infected with Hexacanalis folifer (Cestoda: Lecanicephalidea)

A wild‐caught specimen of the zonetail butterfly ray, Gymnura zonura (Bleeker), harboured numerous specimens of Hexacanalis folifer Cielocha & Jensen, 2011 (Systematic Parasitology, 79, 1–16; Cestoda: Lecanicephalidea) within its spiral intestine. The cestodes were primarily attached in single rows along the base of mucosal folds, each associated with a nodular mucosal thickening. Microscopically, the scolex was embedded within the submucosa and muscularis; the attachment sites were marked by ulceration and necro‐proliferative inflammation demarcating the parasite from normal host tissues. Physical attachment of the cestode was restricted to the anterior portion of its scolex where presumed tegumental secretions from the apical organ contributed to a cementing intermediate layer blending with necrotic host cells. The presence of tegumental differentiation between the apical organ and the scolex proper, associated with presumed different roles in attachment, correlated with ultrastructural observations of the surface modifications on the scolex. Despite the locally severe pathological change, insignificant morbidity owing to this particular host–parasite relationship is suggested.     

覆带车辆松软路面行驶阻力系数与附着系数关系研究

我国未来陆军转型的重点是全域机动作战,这要求陆军装备在各种不同的土壤条件下具有良好的机动性能。然而我国广泛分布着各种类型的松软路面,这些松软路面对履带车辆的机动性能影响很大。作者通过土力学原理假定松软路面的行驶阻力系数与附着系数之间有一定的关系．并得出了不同土壤类型的行驶阻力系数与土壤附着系数之间的公式,并通过收集的数据说明该假设是合理,这为预测履带车辆行驶于松软路面的机动性能提供了参考。     

海水网箱网衣防污技术的研究进展

海水网箱养殖中,网衣污损附着物会影响网箱设施安全及其养殖鱼类的健康生长,因此,网衣防污是网箱养殖业备受关注的问题.本文在简述海水网箱网衣分类与特点的基础上,重点介绍了人工清除法、防污涂料法、机械清除法、金属合金网衣防污法、箱体转动防污法、生物防污法、网衣本征防污法等网衣防污技术最新研究进展;结合本课题组在网衣防污方面的...     

E2蛋白介导猪瘟病毒的细胞吸附与内化

【目的】已有研究显示,猪瘟病毒(CSFV)通过网格蛋白介导的内吞作用侵入宿主细胞,然而参与侵入过程的病毒蛋白尚待阐明。研究旨在明确E2蛋白在CSFV侵入过程中的作用。【方法】通过瞬时转染包装携带E2基因的慢病毒,将慢病毒转导悬浮293细胞构建稳定表达重组E2蛋白的悬浮293细胞系,利用亲和层析的方法纯化重组E2蛋白,同时优化表达时间以增加蛋白产量。利用SDS-PAGE和Western blotting分别鉴定了重组E2蛋白的表达水平及其反应原性。通过感染试验、吸附试验以及内化试验分别探究了E2蛋白对CSFV感染、吸附以及内化的影响。将重组E2蛋白免疫BALB/c小鼠制备多克隆抗体,通过阻断ELISA检测血清中多克隆抗体的阻断率。利用制备的多克隆抗体与CSFV感作后进行吸附和内化试验,进一步探究了E2蛋白在介导CSFV吸附和内化中的作用。【结果】通过倒置荧光显微镜观察转导慢病毒后的细胞系,与对照细胞相比可见明显的绿色荧光,表明慢病毒成功转导悬浮293细胞。SDS-PAGE结果显示,在还原和非还原条件下均出现与预期大小相符的蛋白条带,经Western blotting验证,上清中表达的重组E2蛋白能够被抗E2蛋白单克隆抗体WH303所识别,表明构建的悬浮293细胞系能够表达重组E2蛋白。通过优化表达条件,悬浮293细胞培养第8天时上清中重组E2蛋白浓度最高可达5.84μg·m L-1。可溶性蛋白阻断试验结果显示,重组E2蛋白具有阻断CSFV感染的活性。利用重组E2蛋白在病毒入侵过程中处理细胞对CSFV的感染同样具有显著抑制作用;阻断ELISA和中和试验结果显示,针对E2蛋白的多克隆抗体能够阻断CSFV感染,且具有良好的中和活性;吸附试验和内化试验证明,重组E2蛋白处理细胞能够显著抑制CSFV的内化,而利用多克隆抗体与CSFV感作后能够显著抑制其吸附。【结论】E2蛋白参与CSFV吸附和内化。     

SrfC of Pseudomonas cichorii JBC1 affects its attachment to the host surface and host tissue infection

Plant pathogenic Pseudomonas species produce effectors, toxins and cyclic lipopeptides to infect various host plants. Despite many studies aiming to understand the underlying mechanisms of virulence in Pseudomonas spp., the function of genes in the srf gene cluster including srfC, which was formerly known as HopL1, remains undetermined. To investigate the roles of srf genes in the virulence of the bacterial pathogen, each srfA, srfB, srfC and srfD gene from the srf cluster of Pseudomonas cichorii JBC1 was knocked out. When tomato seedlings were infected with the knockout mutants by flood inoculation, disease incidence was suppressed only in srfC-defective mutants (∆srfC) compared to wildtype. Interestingly, when the ∆srfC strain was inoculated directly into the apoplast of tomato leaves by vacuum infiltration, disease developed similar to that of the wildtype. In addition, the ∆srfC strain showed defective swarming motility and biofilm formation, and the attachment of ∆srfC cells on the leaf surface was significantly reduced compared to wildtype. Furthermore, droplets of the ∆srfC culture supernatant did not spread on a hydrophobic surface, unlike the wildtype. The results indicate that the SrfC protein plays important roles in swarming motility, biofilm formation and attachment/colonization on host surfaces; thus, it is beneficial for the pathogen's dispersion and entry into host tissues and consequently contributes to disease development. This study elucidates for the first time the functional role of srfC in P. cichorii virulence. The results will broaden understanding of plant and bacterial pathogen interactions.     

Influence of residents’ place attachment on heritage forest conservation awareness in a peri-urban area of Guangzhou,China

This study explored the role of community place attachment on heritage forest (feng shui woodland) conservation awareness in the peri-urban areas of Guangzhou. Questionnaire surveys were administered to glean the views of the local residents living near heritage forests. The results suggested that residents’ place attachment was significantly associated with positive perceptions, attitudes and ecologically responsible behaviours towards the heritage forests in their community. The findings revealed that traditional and cultural aspects can be an important focus of attention for local residents with higher levels of place attachment, as heritage forests offer not only ecosystem services but also feng shui value—a traditional vernacular belief in South China. This study clearly demonstrated that cultural bonding can be an important element in facilitating the environmental awareness of the local residents regarding heritage forest conservation.     

Host-parasite soil communities and environmental constraints: Modelling of soil functions involved in interactions between plant-parasitic nematodes and Pasteuria penetrans

Nematodes belonging to the genus Meloidogyne are the most ubiquitous and widespread plant-parasitic nematodes. They occur worldwide, are polyphagous and can parasitize most cultivated plants leading to reduced crop yields. They are especially harmful in developing countries because of the lack of suitable and feasible management strategies. Among all the control practices (chemicals, physical techniques, cultural practices, resistance), the use of natural enemies as biological control agents is the most recently developed. Pasteuria penetrans which is an obligate Gram-positive, endospore-forming bacterium, is perhaps the most promising plant-parasitic nematode biocontrol agent. Despite much research conducted on prey-predator interactions (host-parasite specificity, mechanisms of attachment, field efficacy), the influence of the soil environment on host-parasite interactions is poorly understood even when the soil appears to be the key factor. Beyond common studies on the influence of climatic conditions on the attachment of endospores of P. penetrans to nematodes, more knowledge about the systemic interactions between plants, soil water dynamics, soil texture and structure, and other biota on the parasitism of nematodes by P. penetrans would improve their utilization as biological control agents. The aim of this review is to analyze the literature dealing with the influence of the soil on nematode - P. penetrans interactions in order to suggest a helpful conceptual model based on partitioning the Pasteuria population in sub-populations according to their soil habitat (dispersible and non-dispersible aggregates, microporosity, macroporosity), not all of them being available for attachment and infection on nematodes. Such concerns should be taken into account by epidemiologists for improving biological management strategies based on the use of this bacterium.     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。