Identification of novel juvenile-hormone signaling activators via high-throughput screening with a chemical library

Juvenile hormone (JH) is an insect-specific hormone that regulates molting and metamorphosis. Hence, JH signaling inhibitors (JHSIs) and activators (JHSAs) can be used as effective insect growth regulators (IGRs) for pest management. In our previous study, we established a high-throughput screening (HTS) system for exploration of novel JHSIs and JHSAs using a Bombyx mori cell line (BmN_JF&AR cells) and succeeded in identifying novel JHSIs from a chemical library. Here, we searched for novel JHSAs using this system. The four-step HTS yielded 10 compounds as candidate JHSAs; some of these compounds showed novel basic structures, whereas the others were composed of a 4-phenoxyphenoxymethyl skeleton, the basic structure of several existing JH analogs (pyriproxyfen and fenoxycarb). Topical application of seven compounds to B. mori larvae significantly prolonged the larval period, suggesting that the identified JHSAs may be promising IGRs targeting the JH signaling pathway.     

桉树不同成熟度叶片营养元素内循环特征

揭示桉树人工林不同成熟度的叶片器官所需营养元素变化以及土壤肥力对其影响,对于桉树营林和科学施肥具有重要的生产指导意义。选取广西隆安县小林镇和田东县思林镇的桉树2代萌芽林作为研究对象,测定两个人工林嫩叶、成熟叶、黄叶的C、N、P、K、B、Ca、Mg以及土壤C、N、P、K、Ca、Mg元素含量,并进行相关分析。结果表明,植物叶片的N、P、K、Mg营养元素转移规律是黄叶向成熟叶和嫩叶转移,但C、Ca、B营养元素则是随着叶片的生长发育逐渐积累,黄叶中含量最高,说明施肥时应关注Ca、B元素的持续和有效供给。两片人工林都表现出类似的规律,说明土壤肥力的差异不影响桉树人工林叶片营养元素的内循环规律。桉树嫩叶营养元素含量及其生态化学计量比学特征具有与成熟叶和黄叶不同的表征,在营养物质研究中应予以足够重视。     

New ways and new hopes for IGR development

Insect Growth Regulators (IGRs) represent advanced, bio-rational insecticides. This Special Issue reflects progress in IGR development that has been enabled by insight into the molecular principles of biosynthetic or hormone signaling pathways. The unifying principle is aiming at processes and molecular targets that are unique to arthropods and ideally to narrower insect taxa representing pests or disease vectors. While some strategies of obtaining the desired compounds for chemical intervention rely on rational, structure-based design or computational power, others exploit technologies allowing automated, high-throughput screening of large chemical libraries. All avenues leading to selective and environmentally safe pest control are valid as we face the imminent threat of the declining world insect population.     

特殊医学用途婴儿配方食品中氯的国标检测方法适用性

依据GB 5009.44—2016《食品安全国家标准 食品中氯化物的测定》，对特殊医学用途婴儿配方食品中氯的检测方法适用性展开研究。结果表明：采用GB 5009.44—2016第三法（银量法）检测特殊医学用途婴儿配方食品中乳蛋白部分水解配方、乳蛋白深度水解配方、氨基酸配方得到的样品加标回收率分别为95%～108%、98%～125%、100%～106%，相对标准偏差为12.7%～32.9%；采用GB 5009.44—2016第一法（电位滴定法）得到的检测结果低于第三法检测结果。     

5种药物对异育银鲫"中科3号"受精卵孵化的影响

在水温21~23℃,pH 6.2~6.5条件下,采用半静水试验法,按等对数间距设置药物质量浓度梯度,日换水50%,补充药物50%,24 h观察记录1次,比较美婷Ⅱ、霉灵、纳他霉素、杀毒矾和高锰酸钾5种药物对异育银鲫"中科3号"受精卵水霉抑制作用及孵化率的影响。试验结果显示,试验药物对受精卵水霉生长均有一定抑制作用,其抑霉率为美婷Ⅱ>霉灵>高锰酸钾、纳他霉素和杀毒矾,但杀毒矾对异育银鲫"中科3号"受精卵的毒副作用较大,显著降低了受精卵孵化率,不宜使用;美婷Ⅱ、霉灵、纳他霉素和高锰酸钾对异育银鲫"中科3号"受精卵的适宜使用质量浓度分别为4.90~6.50、1.97~3.87、1.50、2.50 mg/L,使用方法为长时间浸浴,可有效抑制受精卵孵化过程中水霉的生长,显著提高受精卵孵化率,适合在异育银鲫"中科3号"受精卵孵化过程中使用。     

盐度对珍珠龙胆石斑鱼幼鱼渗透调节与耗氧率的影响

为研究盐度对珍珠龙胆石斑鱼（）渗透调节与耗氧率的影响，设计实验一，将（162.5±12.1）g珍珠龙胆石斑鱼置于不同盐度（6、12、18、24、30）下养殖10 d，测定血清渗透压及Na⁺、Cl^-、K⁺离子浓度。实验结果表明，随盐度的升高血清渗透压及Na⁺、Cl^-、K⁺离子浓度也随着升高，各组[Na⁺]：[Cl^-]比值无显著差异（>0.05）；经回归分析得到血清等渗点渗透压为365.95 mOsm/kg，所对应盐度为12.75。实验二，将（26.4±2.7）g幼鱼置于不同盐度（6、12、18、24、30）下养殖30 d，测定在开始暴露后0 h、3 h、24 h、72 h鳃Na⁺/K⁺-ATPase活性及表达和第30天耗氧率，结果表明鳃Na⁺/K⁺-ATPase活性随盐度的增大呈“U”形变化；鳃Na⁺/K⁺-ATPase α1基因表达量波动较大，在72 h后随盐度增大先降低后增加，变化趋势与酶活性一致；第30天耗氧率随盐度的增加先降低后增加又降低。综上所述，珍珠龙胆石斑鱼幼鱼10 d内能够完全适应6~30盐度急性变化，耗氧率除了受离子渗透调节的影响，还可能与其生活史阶段有关。     

Met基因在黏虫生殖中的功能分析

保幼激素(juvenile hormone, JH)是由咽侧体分泌的倍半萜类化合物,可以调控昆虫的很多生理过程,如发育、变态、生殖等。作为bHLH-PAS(helix-loop-helix-Per-ARNT-Sim)转录因子家族成员之一的methoprene-tolerant (Met)是JH的受体,在JH的信号传导过程中有非常重要的作用。本研究通过实时荧光定量PCR结合RNAi技术测定了沉默Met基因后黏虫Mythimna separata的Vg基因表达、卵巢发育和生殖行为,旨在探究Met基因在黏虫生殖过程中的功能。结果表明当Met基因沉默后,与卵巢发育密切相关的卵黄原蛋白(vitellogenin, Vg)基因表达量下调了50%,从而显著抑制了卵巢发育,并导致产卵显著延迟、产卵历期显著缩短,产卵量显著下降。结果表明Met基因是黏虫生殖发育过程中的关键受体基因,它通过调节后续Vg的表达和沉积,来达到控制卵巢发育,从而调控生殖作用。     

Differences in the effectiveness of reproduction among ten breeding strains of the common carp Cyprinus carpio L. after stimulation of ovulation with carp pituitary homogenate or [(D‐Ala6, Pro9NEt) mGnRH‐a + metoclopramide] (Ovopel)

This study focused on the reproduction effectiveness of 10 breeding strains of common carp (Polish strains 2, 3, 6; Hungarian strains 0, W, 7; Lithuanian strain B; French strain F; Israeli strain D and Yugoslavian strain J) after stimulation of ovulation with carp pituitary homogenate or Ovopel. The percentage of females with recorded ovulation became higher after Ovopel treatment in as many as eight breeding strains (2, 3, 6, 0, W, B, F, D). The interaction between the spawning agent and the breeding strain was statistically significant (P ≤ 0.05) for the mass of spawn and non‐significant for traits determining the quality of eggs. Among the 10 breeding strains, in 4 (3, 7, B, J) the least‐squares means (LSM) for the weight of egg (g) were higher for fish stimulated with Ovopel. Among the strains tested, in seven (3, W, F, J, 2, 7, B), the LSM for the percentage of living embryos after 36 h incubation were higher for fish treated with Ovopel. The evaluation of reproduction effects based on the values of such parameters as the percentage of ovulating females, weight of eggs (g) and the percentage of live embryos (36 h) showed that after Ovopel treatment the poorer effects were obtained only for strains 6, 0 and D.     

Isolation of infectious microalga Prototheca wickerhamii from a carp (Cyprinus carpio) – a first confirmed case report of protothecosis in a fish

Protothecosis is a rare infection caused by environmentally ubiquitous achlorophyllic microalgae of the genus Prototheca. Here, we describe a first case of protothecosis in a carp (Cyprinus carpio), which is at the same time the first case of protothecosis in a fish, confirmed by phenotype‐ and molecular‐based methods, including PCR sequencing of the rDNA cluster and protein profiling using matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry.     

射流式鱼泵输送草鱼的性能研究

为了分析射流式鱼泵输送草鱼的性能及其损伤因素,文章设计了一台喉管直径为60 mm的射流式鱼泵,开展了草鱼输送实验,并采用高速摄影和计算流体力学方法进行了研究。结果显示,该射流式鱼泵在扬程2.24m时最高草鱼输送能力达918 kg·h~(-1),其所需水功率为2.83 k W。进一步的检测表明,部分实验鱼有鳞片脱落的情况,但未出现游泳异常,解剖后也未发现内脏受损等情况;实验鱼在过泵后呼吸频率及部分血液指标存在明显变化,但在24 h内基本可以恢复。数值模拟和高速摄影方法分析得出,剪切层是造成实验鱼泵内鳞片脱落的主要原因,撞击伤是由内流偏转诱导实验鱼撞击泵内壁面产生的,包含压力梯度在内的水力因素都可能使实验鱼产生应激反应。但由于鱼类在泵内时间极短,上述因素都不会致实验鱼死亡。