番茄斑萎病毒病抗性种质筛选及人工接种鉴定方法优化

对154份番茄材料(包括普通番茄76份,樱桃番茄78份)进行两年两次田间番茄斑萎病毒病的病情指数调查,筛选出14份对番茄斑萎病毒病具有稳定抗性的番茄材料,利用sw-5-2共显性SCAR标记对田间表现抗病的材料进行分子标记鉴定,发现3份抗病材料携带抗番茄斑萎病毒病的Sw-5基因。为缩短番茄斑萎病毒病人工接种鉴定周期,以含有sw-5的抗病材料H8和感病材料M82为研究对象,设置4、6、8、10片真叶4个接种时期,分别在接种后14、21、28 d进行病情指数调查和抗性分级,结果表明,6片真叶期接种,接种后28 d进行病情调查即可有效鉴别植株番茄斑萎病毒病抗性,与8、10片真叶期接种效果相同,人工接种抗病性鉴定效率显著提升。     

Effects of dietary protein and lipid levels with different protein‐to‐energy ratios on growth performance,feed utilization and body composition of juvenile red‐spotted grouper,Epinephelus akaara

An 8‐week feeding trial was conducted to assess dietary protein and lipid levels on growth performance, feed utilization and body composition of juvenile red‐spotted grouper (7.85 ± 0.03 g fish^?1). Nine semi‐purified diets were formulated containing varying protein levels (440–520 g kg^?1, dry matter) and lipid levels (60–120 g kg^?1, dry matter). The weight gain of juvenile Epinephelus akaara was affected by dietary protein (p = .005) and its interaction with dietary lipid (p = .020). Viscerosomatic index, intraperitoneal fat ratio and whole‐body lipid level increased with increasing dietary lipid level (p < .001). Nitrogen retention was not affected by dietary protein and lipid, while lipid retention decreased with increasing dietary lipid level (p < .001). The plasma blood urea nitrogen increased with increasing dietary protein level (p = .003). This study showed that diet with 520 g kg^?1 protein and 60 g kg^?1 lipid with 30.58 mg kJ^?1 P:E provided a maximal growth for this species. Moreover, an increase in dietary lipid levels (from 60 to 90 g kg^?1) could reduce the protein requirement (from 520 to 480 g kg^?1) without affecting the growth performance, while higher fat deposition was observed in fish fed high‐lipid diets.     

Potential of indigenous Bacillus spp. as probiotic feed supplements in an extruded low‐fish‐meal diet for juvenile olive flounder,Paralichthys olivaceus

A 12‐week feeding trial was designed to assess the probiotic potential of indigenous Bacillus amyloliquefaciens and/or Bacillus subtilis singly or in combination with Bacillus licheniformis in an extruded feed for olive flounder (Paralichthys olivaceus) juveniles. A high fish meal (FM) diet (control) and a low‐FM diet containing an alternative protein blend (30% FM replacement, FM30) were formulated. Three other experimental diets were prepared by inclusion of B. amyloliquefaciens (BA), B. subtilis (BS), or a mixture of B. amyloliquefaciens, B. subtilis, and B. licheniformis (BASL) into FM30 diet, with a final concentration of 10⁶ CFU/g diet. Results indicated that the FM30 diet was well tolerated by flounder, and the overall performance was not affected by dietary treatments. Lysozyme activity and total immunoglobulin level were significantly reduced in flounders when fed with the FM30 diet compared with the BASL and BA diets, respectively. The Bacillus additives neither enriched the relative abundance of the corresponding Bacillus spp. in the relevant gut microbiota of olive flounder nor modulated the presumptive gene functions of the gut microbiome. Despite the absence of growth‐promoting effect, the tested probiotics could still be economically viable for use as immunostimulants in commercial flounder diets with partial FM replacement.     

Sublethal effects of nine insecticides on Drosophila suzukii and its major pupal parasitoid Trichopria drosophilae

Background

Although the pupal parasitoid Trichopria drosophilae is used in conservative and augmentative biocontrol of Drosophila suzukii infestations, current pest management strategies mostly rely on multiple insecticide applications. In this context, the aim of the study was to investigate the baseline toxicity of nine insecticides on D. suzukii larvae and their multiple sublethal effects (LC₁₀) on immature stages of the pest feeding on contaminated diet and T. drosophilae developing within the intoxicated host.

Results

Chlorpyriphos and azadirachtin showed the lowest and the highest LC₁₀, the values of which were 9.78 × 10¹³ and 1.46 × 10³ times lower than their recommended label field rate, respectively. Among tested insecticides, imidacloprid, malathion and dimethoate were the only treatments that did not affect the juvenile development time of D. suzukii, while spinosad and the organophosphates chlorpyriphos and dimethoate did not influence fly pupal size. No sublethal effects were recorded on T. drosophilae degree of infestation (DI) and juvenile development time. On the contrary, cyazypyr and dimethoate negatively affected the success of parasitism (SP) and the number of progeny of the pupal parasitoid, in association with malathion for the first parameter and spinosad for the fertility. Compared to the untreated control, more female progeny emerged following azadirachtin exposure, while dimethoate caused the opposite effect. Imidacloprid, lambda-cyhalothrin and spinetoram decreased hind tibia length of emerged parasitoids.

Conclusion

This study provides new insights on the (eco)toxicological profile of nine insecticides and new information needed to support the deployment of T. drosophilae in the field within the sustainable management techniques against D. suzukii. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

船载摇摆胁迫对斑石鲷血液生化指标的影响研究

为了探索鱼类在船载摇摆条件下的应激响应和适应性,为深远海大型养殖平台养殖工艺设计与模式构建提供基础数据和理论依据,利用机械摇摆台模拟船载工况,研究了不同摇摆周期和时间条件下斑石鲷的血液生化指标变化情况。结果表明:(1)短时间摇摆条件下(5 min),摇摆周期10 s组的斑石鲷与空白组无显著性差异;摇摆周期5 s组的斑石鲷血清葡萄糖显著降低、皮质醇和肾上腺素指标显著升高、肌糖原和肝糖原无显著差异。(2)长时间摇摆条件下(60 min),摇摆周期5 s组和10 s组之间斑石鲷无显著性差异。但是,与空白组相比,血清葡萄糖指标均显著降低,皮质醇和肾上腺素指标也均显著升高,肌糖原和肝糖原指标无显著差异。(3)水质变化情况显示,摇摆60 min对于水温、盐度、pH、溶解氧、氨氮等的影响不显著。根据试验结果认为,短期小幅摇摆对斑石鲷不会造成较大影响,而大幅度剧烈摇摆会引起斑石鲷一定程度的应激反应。     

Mature plant and tissue resistance in the groundnut-peanut bud necrosis virus system

Summary Leaves and plants of different ages of a susceptible and two resistant groundnut genotypes were mechanically inoculated with peanut bud necrosis virus, and the percentage of plants with systemic symptoms (incidence) and the incubation period were determined. The incidence decreased sharply in all three genotypes with the age of the inoculated leaves and plants. The incubation period increased with the age of leaves and plants. Apparently, only young tissue of young plants is susceptible, while mature tissue and plants are highly resistant. This mature tissue and plant resistance occurs irrespective of the susceptibility level of the genotype to peanut bud necrosis virus, however, it develops earlier in the resistant than in the susceptible genotypes.Abbreviations IP₅₀ incubation period - PBNV peanut bud necrosis virus - TSWV tomato spotted wilt virus     

不同生理时期梅花鹿血液GSH-Px含量测定及其纯化

研究不同生理时期梅花鹿全血中GSH-Px含量变化及其纯化技术,为开发鹿血抗衰老资源奠定理论基础.用DINB法测定梅花鹿的溶血液、血细胞内容物、血浆和血细胞细胞膜中GSH-Px含量并计算全血GSH-Px含量；利用10％～100％饱和度的(NH4)2SO4盐析和柱层析技术纯化GSH-Px;用SDS-聚丙烯酰胺凝胶电泳测定其亚基相对分子质量.试验结果表明:全血GSH-Px含量以生茸期最高为(1 973.07士25.43)U·mL-1,与配种期的(1 727.74士12.46)U·mL-1差异极显著(P＜0.01),与生茸前期的(1 961.83士16.54)U·mL-1差异不显著(P＞0.05)；GSH-Px的初始比活力为24.9 U·mg-1,经纯化后得到GSH-Px 0.37 mg· mL-1,最终比活力1 347.7U·mg-1,纯化倍数为54.1倍,回收率25.00％；鹿血GSH-Px亚基的相对分子质量为17.2 ku.结果提示生茸期鹿血的GSH-Px含量最高,开发利用价值最大,GSH-Px含量与生理特性相关；鹿血GSH-Px盐析条件为40％～80％饱和度的(NH4)2SO4,此时所得GSH-Px纯化倍数较高.     

Yield performance and pest resistance among peanut genotypes when grown without fungicides or insecticides

Yield trials without fungicides or insecticides were conducted four consecutive years (2007–10) at the University of Georgia, Coastal Plain Experiment Station, Tifton Campus to evaluate for peanut (Arachis hypogaea L.) pest resistance. The most endemic diseases in the southeast U.S. are tomato spotted wilt (TSW) caused by Tomato spotted wilt virus, white mold (WM) caused by Sclerotium rolfsii Sacc, and both early and late leaf spot caused by Cercospora arachidicola Hori and Cercosporidium personatum (Berk & Curt.) Deighton, respectively. The most endemic insects are tobacco thrips (Frankliniella fusca Hinds) and potato leafhopper (Empoasca fabae Harris). Results from these replicated field tests showed significant differences (P ≤ 0.05) among advanced Georgia breeding lines and cultivars. Three Georgia cultivars ‘Georgia-01R’, ‘Georgia-05E’, and ‘Georgia-10T’ consistently produced among the best yields with high levels of resistance to TSW, white mold, leafhoppers, and leaf spot each year. Georgia-01R is a multiple-pest-resistant, runner-type cultivar with late maturity; whereas, Georgia-05E is a multiple-pest-resistant, virginia-type cultivar with medium-late maturity. Georgia-10T is a new runner-type cultivar with high level of TSWV and white mold resistance and late-maturity, similar to Georgia-01R, one of its parents. However, Georgia-10T does not appear to have the high level of leaf spot and leafhopper resistance as Georgia-01R, but it still had high yields in the absence of fungicides or insecticides.