巴氏新小绥螨在马铃薯腐烂茎线虫上的实验种群生命表及其捕食作用

为明确巴氏新小绥螨Neoseiulus barkeri对马铃薯腐烂茎线虫Ditylenchus destructor的捕食能力,以马铃薯腐烂茎线虫和椭圆食粉螨Aleuroglyphus ovatus为猎物饲养巴氏新小绥螨,构建了巴氏新小绥螨的实验种群生命表,并构建了雌成螨对马铃薯腐烂茎线虫的捕食功能反应模型。结果显示,巴氏新小绥螨取食马铃薯腐烂茎线虫后能完成整个生活史,平均世代为6.71 d,产卵前期、产卵期、日产卵量以及雌成螨寿命分别为2.89 d、19.13 d、1.79粒和26.44 d,与取食椭圆食粉螨后的各参数间均无显著差异。巴氏新小绥螨雌成螨对马铃薯腐烂茎线虫的捕食功能反应为Holling Ⅱ型,在温度16~28℃范围内,其攻击系数(a)、捕食能力(a/T_h)、最大日捕食量(1/T_h)均随温度升高而升高,处理时间(T_h)缩短;在28℃时日捕食量达到最高,为52.69条,处理时间最短,为0.019 d;当温度高于32℃时捕食量开始下降。表明巴氏新小绥螨具有防治马铃薯腐烂茎线虫的潜力。     

Factors affecting the virulence of Ralstonia solanacearum and its colonization on tobacco roots

Tobacco bacterial wilt caused by Ralstonia solanacearum is a serious disease affecting tobacco cultivation in southwest China. The response surface methodology was employed to evaluate the optimal conditions of tobacco bacterial wilt, and green fluorescent protein gene (gfp) labelling was applied to monitor the location and survival dynamics of R. solanacearum (Rs::gfp) on tobacco roots and in soil under these optimal conditions. The results showed that the highest wilt incidence was 91.13%, which occurred when the population reached 6.6 × 10⁶ CFU/g soil, the temperature was 30.55 °C, and the humidity was >81.42%. The Rs::gfp densely colonized the root tips and root hairs, and cells of Rs::gfp were observed intermittently in the elongation zone or at the point of the emerging lateral roots. The Rs::gfp number in the rhizosphere soil was 10.75‐, 73.13‐ and 74.86‐times higher than that in the bulk soil at 10, 15 and 20 days after transplantation, respectively. Increased colonization by Rs::gfp was related to the population of the pathogen, the environmental temperature and the humidity in the soil. These three conditions determined whether R. solanacearum would induce tobacco wilt. This is the first study to investigate factors affecting the virulence of a tobacco wilt bacterial pathogen, which is important for conducting field diagnosis and biocontrol of tobacco bacterial wilt.     

胶孢炭疽菌CgSho1基因的克隆与功能分析

HOG-MAPK(high osmolarity glycerol mitogen-activated protein kinase)信号途径是真菌MAPK途径中参与渗透压响应的一条重要通路,在植物病原菌生长发育及致病过程中发挥着重要的作用。Sho1(synthetic high osmolarity-sensitive protein1)是HOG-M APK信号途径上游的一个重要感受器,在不同真菌中常具有不同的功能。本研究从胶孢炭疽菌中克隆了Sho1的同源基因,命名为Cg Sho1,该基因编码一个291个氨基酸的蛋白,含有4个跨膜结构域和一个SH3功能域。利用同源重组的方法获得了该基因的敲除突变体,与野生型相比,敲除突变体表现为营养生长缓慢,菌丝稀疏且疏水性增强,产孢量下降,对氧化压力和渗透压更加敏感,致病力明显减弱。上述结果表明,Cg Sho1参与调控胶胞炭疽菌的营养生长、分生孢子产量、氧化应激反应、渗透压响应及致病性。     

Involvement of a vascular hypersensitive response in quantitative resistance to Ralstonia solanacearum on tomato rootstock cultivar LS‐89

Ralstonia solanacearum causes bacterial wilt disease in Solanaceae spp. Expression of the Phytophthora inhibitor protease 1 (PIP1) gene, which encodes a papain‐like extracellular cysteine protease, is induced in R. solanacearum‐inoculated stem tissues of quantitatively resistant tomato cultivar LS‐89, but not in susceptible cultivar Ponderosa. Phytophthora inhibitor protease 1 is closely related to Rcr3, which is required for the Cf‐2‐mediated hypersensitive response (HR) to the leaf mould fungus Cladosporium fulvum and manifestation of HR cell death. However, up‐regulation of PIP1 in R. solanacearum‐inoculated LS‐89 stems was not accompanied by visible HR cell death. Nevertheless, upon electron microscopic examination of inoculated stem tissues of resistant cultivar LS‐89, several aggregated materials associated with HR cell death were observed in xylem parenchyma and pith cells surrounding xylem vessels. In addition, the accumulation of electron‐dense substances was observed within the xylem vessel lumen of inoculated stems. Moreover, when the leaves of LS‐89 or Ponderosa were infiltrated with 10⁶ cells mL^?1 R. solanacearum, cell death appeared in LS‐89 at 18 and 24 h after infiltration. The proliferation of bacteria in the infiltrated leaf tissues of LS‐89 was suppressed to approximately 10–30% of that in Ponderosa, and expression of the defence‐related gene PR‐2 and HR marker gene hsr203J was induced in the infiltrated tissues. These results indicated that the response of LS‐89 is a true HR, and induction of vascular HR in xylem parenchyma and pith cells surrounding xylem vessels seems to be associated with quantitative resistance of LS‐89 to R. solanacearum.     

Growth and photosynthetic responses of invasive Bidens frondosa to light and water availability: A comparison with invasive and native congeners

Bidens frondosa is a new invasive species in China. However, the mechanisms underlying its invasiveness are still not understood. This study compared the new invader with its invasive congener, Bidens pilosa, and two native congeners, Bidens biternata and Bidens tripartita, in terms of their morphology, growth, biomass allocation and photosynthetic parameters across variant light and water conditions, aiming to explore the traits that are associated with the invasiveness of the invasive species. All these species are annual herbs. The results showed that the four congeners had a similar tendency of plasticity in their morphological and growth traits to varying light and water, but their response was quantitatively different. Most of the morphological and growing variables, as well as the photosynthetic parameters, were affected more strongly by manipulated light levels. Although B. frondosa had a lower total biomass and relative growth rate than the invasive congener, B. pilosa, the trait values related to growth (e.g. plant height, total biomass, relative growth rate and specific leaf area) and the mean value of the plasticity index were higher for the invasive B. frondosa than for the native B. tripartita. These could contribute to the invasiveness of the invasive species. In addition, the native species, B. biternata, is a vigorous weed with a strong adaptive capacity across various light and water gradients, suggesting that it has the potential to be invasive if introduced into areas with suitable conditions for growth.     

大鲵泛素结合酶cgsUBE2L3基因克隆及其在免疫应答中的表达分析

[目的]研究泛素结合酶UBE2L3基因在大鲵免疫应答过程中的作用。[方法]克隆大鲵泛素结合酶基因(cgsUBE2L3),进行相关生物信息学分析,并通过qRT-PCR对其组织分布及免疫刺激下的表达谱进行分析。[结果]成功克隆了cgsUBE2L3基因,该基因全长包含一个462 bp的开放阅读框,编码154个氨基酸,预计蛋白分子量为21.2 ku;cgsUBE2L3氨基酸序列保守性很高,与非洲爪蟾的同源性高达97.4%;此外,qRT-PCR结果显示,cgsUBE2L3基因在大鲵组织中广泛分布,且被LPS感染的大鲵多个免疫组织中cgsUBE2L3的mRNA水平均发生了明显变化。[结论]cgsUBE2L3基因具有高度保守的结构特征,其组织分布具有特异性且参与大鲵抵抗LPS刺激的免疫应答。     

Box-Behnken设计优化黄精多糖酶法提取工艺

采用响应面法,以多糖提取率为评价指标,对酶解温度、酶添加量、酶解时间、料液比4个影响因素进行考察,优化酶法提取黄精多糖的提取工艺,另以Design-Expert 8.05软件对数据进行综合统计分析。结果表明,最优工艺为酶添加量3%、酶解温度54.8℃、酶解时间99 min、料液比1∶22.4(g/m L),经验证黄精多糖提取率为11.22%。利用Box-Behnken响应面法优选的黄精多糖酶法提取工艺稳定可行,可用于黄精多糖的提取。     

七星瓢虫与异色瓢虫对烟蚜的捕食功能反应及寻找效应

[目的]了解不同龄期七星瓢虫与异色瓢虫对烟蚜的控制作用。[方法]研究不同龄期七星瓢虫与异色瓢虫对烟蚜的捕食功能反应及寻找效应。[结果]2种瓢虫的日均实际捕食量随着蚜虫密度的增大而增大。从龄期看,在烟蚜密度相同时,七星瓢虫与异色瓢虫均为成虫对烟蚜的捕食量最大,其次依次为4龄幼虫、3龄幼虫、2龄幼虫、1龄幼虫。通过比较功能反应中的各参数可知,2种瓢虫对烟蚜的攻击率随着龄期的增加而提高,七星瓢虫对烟蚜的攻击率从1龄幼虫的0.562 0增加到成虫的1.174 1,异色瓢虫对烟蚜的攻击率从1龄幼虫的0.595 1增加到成虫的1.170 5;2种瓢虫相比,幼虫时期,七星瓢虫对烟蚜的攻击率小于异色瓢虫,而成虫则相反。七星瓢虫与异色瓢虫对烟蚜的寻找效应是随着猎物的增加而降低。[结论]试验结果为烟蚜的综合防治提供了理论依据。     

Piloting an “Opt-Out” Option for Wildlife Surveys of the General Public

Random sample surveys may provide the best way to collect data that accurately represent public attitudes on wildlife issues, but survey response rates have declined in recent years. Often, little information is collected on why people choose not to participate. In a recent survey of public attitudes toward wolves in Wisconsin, we tested a method that allowed recipients to “opt-out” of participating, as well as indicate their reasons for doing so. Including this option increased our survey responses, and data showed significant differences in demographics between full survey respondents and opt-outs. The most frequently cited reasons for opting-out were lack of knowledge of the topic (63%) and trust in the state to manage wolves without their input (31%). Results suggest that providing a means for survey recipients to indicate why they are not participating can yield multiple benefits, although further testing of this method is needed.     

Tolerability and pharmacokinetic profile of a novel benzene‐poly‐carboxylic acids complex with cis‐diammineplatinum (II) dichloride in dogs with malignant mammary tumours

The pharmacokinetic profile, tolerability and efficacy of benzene‐poly‐carboxylic acids complex with cis‐diammineplatinum (II) dichloride (BP‐C1) were studied in dogs with mammary cancer. A three‐level response surface pathway designed trial was performed on seven dogs. At each level BP‐C1 was administered subcutaneously daily for 7 days followed by a 7‐day rest period in a dose escalating manner. Adverse events according to VCOG‐CTCAE, performance status and tumour progression were recorded. The pharmacokinetic profile followed a two‐compartment model with rapid absorption, short distribution, and a slow elimination phase. The overall elimination half‐life was 125 h. The maximum tolerated dose of BP‐C1 was estimated to be above 0.46 mg kg^?1. A significant reduction in VCOG‐CTCAE toxicity which correlated negatively with increasing dose was found. The dogs' general performance status remained unchanged. No decrease in total tumour burden was found, although temporary tumour reduction was seen in some target tumours.