昆虫对降雨和干旱的响应与适应

水分因子在昆虫的生长发育及其整个生活史中起着至关重要的作用。降雨作为改变环境水分的方式之一,其机械冲刷作用对昆虫具有直接的致死效应,并影响昆虫的生长发育、繁殖及其产卵和取食行为等;干旱作为降雨减少导致的极端环境形式,不仅对昆虫生理产生直接影响,而且还会通过影响寄主植物而间接作用于昆虫;同时,干旱还会改变同一寄主植物上昆虫之间的种间关系,导致群落多样性和稳定性的变化以及种群演替的发生。本文综述了气候变化背景下降雨和干旱对昆虫生长发育和繁殖的影响,并介绍了迁飞型昆虫、群居型昆虫、土壤害虫等对降雨和干旱的行为反应;此外,还详细介绍了昆虫对降雨和干旱的适应对策(包括对水分因子的行为适应对策、滞育和迁飞对策等),并建议利用环境水分(尤其是土壤水分)调控措施(如人工降雨和灌溉等)来防治农业害虫。     

Cu2+和阿维菌素及其复合胁迫对亚洲玉米螟生长发育和繁殖行为的影响

【目的】探究农田重金属Cu²⁺和农药阿维菌素(avermectin)及其复合胁迫对亚洲玉米螟Ostrinia furnacalis的生长发育和繁殖行为的影响。【方法】在人工饲料中分别和同时添加50 mg/kg Cu²⁺和0.039 mg/L阿维菌素(对亚洲玉米螟3龄幼虫的LC₁₀浓度),得到含Cu²⁺(Cu)、阿维菌素(Av)和同时含二者(Av+Cu)的3种处理的饲料,以正常人工饲料为空白对照组。实验室条件下用这4种饲料饲养亚洲玉米螟初孵幼虫,系统调查和记录其生长发育参数(幼虫历期、蛹历期、蛹重、成虫体重、生长速率、成虫羽化率和成虫寿命)、求偶行为参数(求偶率和平均求偶持续时间)、定向行为参数(起飞率、定向率、平均反应时间、飞过半程率和降落至信息素源率)以及繁殖参数(单雌产卵量和卵孵化率)。【结果】Cu和Av及其复合胁迫(Av+Cu)对亚洲玉米螟的生长发育和繁殖均产生一定影响。一方面,Cu单独处理后亚洲玉米螟的雌雄虫胚后发育期(幼虫历期+蛹历期)较空白对照组显著缩短;而Av单独处理后,亚洲玉米螟雌雄...     

大气二氧化碳浓度升高对植物-昆虫相互关系的影响

综述了CO2浓度升高对植物与昆虫相互关系影响的研究结果。大量研究表明,高浓度CO2对植物生理生化活动有显著的影响,植物营养物质的变化对植食性昆虫亦产生不同程度的影响,高浓度CO2条件对咀嚼式口器昆虫的取食、生长发育和生殖有不同程度的不良影响,昆虫为了获得足够的氮素营养而增加取食强度和时间,从而更易于受到天敌的攻击,这些昆虫的生长率、繁殖和生存率有下降的趋势;而对刺吸韧皮部汁液的昆虫来说,多引起种群数量增加或无显著影响。并对研究中存在的问题进行了分析,提出了今后研究的方向。     

取食重金属铜对棕尾别麻蝇亲代及子代生长发育与繁殖的影响

为了评估取食含重金属铜饲料对棕尾别麻蝇Boettcherisca peregrine亲代及子代的生长发育与繁殖的影响,在室内给棕尾别麻蝇初产幼虫饲喂含不同浓度（200, 400,800和1 600 µg/g）Cu²⁺的饲料直至化蛹,并对亲代和子代的生长发育和繁殖有关指标进行了观察和分析。结果表明：低浓度的Cu²⁺（200 µg/g）对其体重和体长起促进作用,但对幼虫历期、化蛹率、蛹历期、羽化率、性比、交配率和产仔量无显著作用;较高浓度的Cu²⁺ 则有抑制作用,且Cu²⁺处理浓度越高,亲代幼虫、蛹和雌雄成虫的体重越轻,幼虫和蛹的体长越短,化蛹率、羽化率、交配率和产仔量越低,幼虫历期和蛹期越长,成虫寿命越短。但Cu²⁺处理对成虫性比则无显著的影响。相比之下,经Cu²⁺处理后雌虫所产的子代若不再经Cu²⁺处理,其子代生存、生长发育与繁殖则基本不受影响,说明Cu²⁺对亲代的影响不能遗传至子代。此外,还探讨了该蝇亲代与子代体内Cu²⁺含量在其变态过程中的变化。     

用做饲料的昆虫资源

昆虫食物简单,繁殖快,数量大,属于可持续利用资源。科学研究和营养分析表明,大部分昆虫的蛋白质含量占干重的４０％以上,有的甚至接近或超过优质鱼粉的含量,并且各种营养成分及生物生长发育所必需的微量元素和维生素也比较全面,开发潜力大,是用其它方法生产动物性蛋白所无法比拟的,因此有计划地开发昆虫蛋白资源是解决动物性蛋白饲料的有效途径。像蝇蛆、黄粉虫、蝗虫、蚕蛹、蝼蛄、蝉等昆虫作为优质蛋白饲料饲养畜禽已被世人公认,许多科学工作者都把人工饲养昆虫作为解决动物性蛋白饲料来源的主攻方向。现就目前已开发的饲用昆虫…     

病毒-植物互作对介体昆虫生物学特性的影响

大部分植物病毒需要介体来传播,而昆虫则是其最重要的介体类别。植物-病毒-介体昆虫的互作关系既复杂又特异,而病毒由于其繁殖迅速、变异快而成为三者协同进化的推动者,以有利于病毒的有效传播。病毒对介体昆虫的影响分直接影响和间接影响两个方面,间接影响即是病毒侵染寄主植物后会引起植物的光合作用、次生代谢、营养成分、信号途径等发生变化,继而影响介体昆虫的寄主选择行为、生长发育、繁殖力等生物学特性,最终会影响介体对于病毒的传播。综述了病毒侵染寄主植物对刺吸式昆虫生物学特性的影响,以期为防治植物病毒性病害提供依据。     

植物铜转运蛋白的结构和功能

铜(Cu)是植物必需的微量营养元素, 参与植物生长发育过程中的许多生理生化反应。Cu缺乏或过量都会影响植物的正常新陈代谢过程。因此, 植物需要一系列Cu转运蛋白协同作用以保持体内Cu离子的稳态平衡。通常, Cu转运蛋白可分为两类, 即吸收型Cu转运蛋白(如COPT、ZIP和YSL蛋白家族)和排出型Cu转运蛋白(如HMA蛋白家族), 主要负责Cu离子的跨膜转运及调节Cu离子的吸收和排出。然而, 最近有研究表明, 有些Cu伴侣蛋白家族可能是从Cu转运蛋白家族进化而来, 且它们在维持植物细胞Cu离子稳态平衡中也具重要功能。该文对Cu转运蛋白和Cu伴侣蛋白的表达、结构、定位及功能等研究进展进行综述。     

植物干旱胁迫对植食性昆虫及其天敌的影响

全球正经历以变暖为主要特征的气候变化,由此带来的干旱将对农业生态系统造成重要影响。本文综述了干旱胁迫下寄主植物对植食性昆虫及其天敌影响的国内外最新研究进展。在干旱胁迫下,寄主植物物理性状、营养状况和次生代谢物质等均发生变化,这些变化导致植食性昆虫的生存环境和营养物质的获取等方面发生改变,从而影响了害虫生长发育和种群动态。干旱胁迫还导致寄主物候变化与昆虫发生不同步,使害虫缺乏食物。另外干旱也会引起植食性害虫天敌的种群发生变化,从而对植食性昆虫种群数量产生间接的影响。     

昆虫对全球气候变暖的响应

过去的100年全球地表平均温度显著上升,全球气候变暖对生物的影响引起世界范围内的广泛关注。和其他生物一样,昆虫也受到了气候变暖的影响,如繁殖发育速度增快、遗传变异、种群多样性降低、分布区扩大、种群爆发、外来入侵、种群灭绝等等。全球变暖引起的昆虫响应对农林业以及人类健康存在潜在风险,因此本文主要从物候、分布区、生长发育及繁殖、形态、行为与生理、分子水平这些方面综述全球气候变暖背景下昆虫如何响应,并讨论了目前研究动态和未来的研究方向,意在为气候变化条件下昆虫科学管理策略(如种群监控、模型预测、风险评估、遗传多样性、抗性遗传等)提供指导意义。     

昆虫对植物次生物质的代谢适应机制及其对昆虫抗药性的意义

植物次生物质(plant secondary metabolites)对昆虫的取食行为、生长发育及繁殖可以产生不利影响,甚至对昆虫可以产生毒杀作用。为了应对植物次生物质的不利影响,昆虫通过对植物次生物质忌避取食、解毒代谢等多种机制,而对寄主植物产生适应性。其中,昆虫的解毒代谢酶包括昆虫细胞色素P450酶系（P450s）及谷胱甘肽硫转移酶（GSTs）等,在昆虫对植物次生物质的解毒代谢及对寄主植物的适应性中发挥了重要作用。昆虫的解毒酶系统不仅可以代谢植物次生物质,还可能代谢化学杀虫剂,因而昆虫对寄主植物的适应性与其对杀虫剂的耐药性甚至抗药性密切相关。昆虫细胞色素P450s和GSTs等代谢解毒酶活性及相关基因的表达可以被植物次生物质影响,这不仅使昆虫对寄主植物的防御产生了适应性,还影响了昆虫对杀虫剂的解毒代谢,因而改变昆虫的耐药性或抗药性。掌握昆虫对植物次生物质的代谢适应机制及其在昆虫抗药性中的作用,对于明确昆虫的抗药性机制具有重要的参考意义。本文综述了植物次生物质对昆虫的影响、昆虫对寄主植物次生物质的代谢机制、昆虫对植物次生物质的代谢适应性对昆虫耐药性及抗药性的影响等方面的研究进展。     

Acclimation of Daphnia magna to environmentally realistic copper concentrations

It may be hypothesised that as the bioavailable background concentration of an essential metal increases (within natural limits), the natural tolerance (to the metal) of the acclimated/adapted organisms and communities will increase. In this study the influence of acclimation to different copper concentrations on the sensitivity of the freshwater cladoceran Daphnia magna Straus was investigated. D. magna was acclimated over three generations to environmentally relevant copper concentrations ranging from 0.5 to 100 microg Cu/l (copper activity: 7.18 x 10(-15) to 3700 x 10(-12) M Cu2+). A modified standard test medium was used as culture and test medium. Medium modifications were: reduced hardness (lowered to 180 mg CaCO3/l) and addition of Aldrich humic acid at a concentration of 5 mg DOC/l (instead of EDTA). The effects of acclimation on these organisms were monitored using acute mortality assays and long-term assays in which life table parameters, copper body concentrations and energy reserves were used as test endpoints. Our results showed a two-fold increase in acute copper tolerance with increasing acclimation concentration for second and third generation organisms. Copper acclimation concentrations up to 35 microg Cu/l (80 pM Cu2+) did not affect the net reproduction and the intrinsic growth rate. The energy reserves of the acclimated daphnids revealed an Optimal Concentration range (OCEE) and concentrations between 5 and 12 microg Cu/l (0.5-4.1 pM Cu2+) and 1 and 35 microg Cu/l (0.023-80 pM Cu2+) seemed to be optimal for first and third generation daphnids, respectively. Lower and higher copper concentrations resulted in deficiency and toxicity responses. It was also demonstrated that up to 35 microg Cu/l, third generation daphnids were able to regulate their total copper body concentration. These results clearly indicate that bioavailable background copper concentrations present in culture media have to be considered in the evaluation of toxicity test results, especially when the toxicity data are used for water quality guideline derivation and/or ecological risk assessment for metals.     

Heavy metal stress can prime for herbivore-induced plant volatile emission

Heavy metals are important pollutants that can severely impact ecological foodwebs. In addition to direct toxic effects, these contaminants have been suggested to disrupt chemical communication channels between plants and insects that rely on volatile organic compounds (VOCs). We investigated how different concentrations of copper (Cu) and cadmium (Cd) stress affect the capacity of Zea mays to synthesize VOCs in the presence and absence of herbivorous insects. Hydroponically grown maize exposed to a high and low concentration of either Cu or Cd showed stunted growth and lower photosynthetic capacities. Herbivores feeding on stressed plants also had attenuated growth rates. Heavy metal treatment alone did not induce VOC emission in maize plants; however, the higher Cu dose was found to prime for enhanced volatile production that can be triggered by caterpillar feeding. Cu stress correlated with increased levels of reactive oxygen species in roots and priming of herbivore-induced jasmonic acid in leaves. Plants challenged with Cd and herbivory did not differ in responses compared with herbivore-damaged controls with no heavy metals added to the substrate. For Cu stress, our results support the 'single biochemical mechanism for multiple stressors' model which predicts overlapping signalling and responses to abiotic and biotic stress factors.     

铜离子稳态平衡分子机理研究进展

铜离子是生物体不可缺少的微量元素。作位酶的辅助因子,铜离子驱动着包括细胞呼吸、神经递质的传递、铁离子的摄取和抵抗氧化应激在内的重要生理过程。然而,过量时,铜离子是有害的,能损坏像DNA、蛋白质和脂肪这样的生物分子。正因为如此,生物体必须平衡细胞体内铜离子的水平。铜离子稳态平衡相关的遗传缺陷是造成Menke和Wilson疾病的原因。铜离子也被发现与癌症和神经退行性疾病有关。对酵母和其他生物体的研究发现,存在铜离子的摄取、分送、储存、排泄和抵抗毒性水平铜离子的专一机制。调控这些专一机制的铜离子信号分子是细胞平衡铜这个必不可少却又有害的离子的关键。     

Copper transport and Alzheimer’s disease

This brief review discusses copper transport in humans, with an emphasis on knowledge learned from one of the simplest model organisms, yeast. There is a further focus on copper transport in Alzheimer’s Disease (AD). Copper homeostasis is essential for the well-being of all organisms, from bacteria to yeast to humans: survival depends on maintaining the required supply of copper for the many enzymes, dependent on copper for activity, while ensuring that there is no excess free copper, which would cause toxicity. A virtual orchestra of proteins are required to achieve copper homeostasis. For copper uptake, Cu(II) is first reduced to Cu(I) via a membrane-bound reductase. The reduced copper can then be internalised by a copper transporter where it is transferred to copper chaperones for transport and specific delivery to various organelles. Of significance are internal copper transporters, ATP7A and ATP7B, notable for their role in disorders of copper deficiency and toxicity, Menkes and Wilson’s disease, respectively. Metallothioneins and Cu/Zn superoxide dismutase can protect against excess copper in cells. It is clear too, increasing age, environmental and lifestyle factors impact on brain copper. Studies on AD suggest an important role for copper in the brain, with some AD therapies focusing on mobilising copper in AD brains. The transport of copper into the brain is complex and involves numerous players, including amyloid precursor protein, Aβ peptide and cholesterol.     

生物耐铜的分子机理及铜污染环境的生物联合修复

铜是动植物和人类必需的微量元素,缺乏或过多都将产生不良影响。随着社会经济的发展,人类活动对环境的干扰日益加剧,工业和农业生产活动常可导致土壤铜污染,铜已成为土壤重金属污染的主要元素之一。总结了铜在植物体内的自发内稳态调节机制,在细菌和真菌体内的吸收、分布、解毒和调节因子,同时以蚯蚓为例简要阐述了土壤动物对铜的解毒机理;从分子生物学角度对重金属铜在生物体内的代谢机理及生物对环境中过量铜的联合修复研究进展进行了综述,以期为铜污染环境的植物、微生物和动物联合修复的分子机理研究提供借鉴。     

Copper toxicity: evidence for the conversion of cupric to cuprous copper in vivo under anaerobic conditions.

We have determined the toxicity to cells of Escherichia coli B of cupric copper applied under aerobic and anaerobic conditions in two ways. The growth of cells in liquid medium incorporating cupric copper shows differential inhibition, comparing aerobic and anaerobic conditions--toxicity being greater under anoxia. The growth of colonies upon agar plates incorporating cupric copper does not show such a differential effect. We conclude that colonies on plates are largely anoxic even when incubated aerobically. EPR spectra of cells obtained at various times after application of cupric copper under anoxic conditions indicate the conversion of a considerable proportion of the Cu(II) to a non-paramagnetic species, probably Cu(I). We demonstrate that Cu(I) is more toxic than Cu(II) to cells when applied under anoxic conditions and conclude that the difference in toxicity of Cu(II) applied to cells under aerobic and anaerobic conditions results from the greater extent of reduction of Cu(II) to Cu(I) under anaerobic conditions.     

Copper and the biological evolution

Copper is contained in a number of enzymes and proteins. A remarkable feature is that except for the electron-carrying blue copper proteins (azurin and plastocyanin) and copper-containing cytochrome c oxidase found in some cyanobacteria and some aerobic bacteria, all copper enzymes and proteins are found only in eukaryotes. In the early and middle precambrian period when the stationary oxygen pressure in the atmosphere was quite low, copper existed as either metallic or cuprous sulfides which are very insoluble in aqueous media; thus copper might have been unavailable to organisms. The time when copper became Cu(II) upon rise of the atmospheric oxygen pressure and thus became available to organisms seems to be in the middle of Proteozoic era when first eukaryotic organisms seem to have appeared on earth. Thus copper may be considered to be an indicator element for the atmospheric evolution (switching from anoxygenic to oxygenic) and the evolution of higher organisms (eukaryotes).     

Blocking creatine kinase refolding by trace amounts of copper ions

Creatine kinase (CK) is a key enzyme to maintain the energy homeostasis in vertebrate excitable tissues. Due to its importance in cellular energetics, the activity and level of CK are crucial to cellular and body functions. CK is sensitive to oxidative stresses and is thought to be one of the main targets of oxidative modification in neurodegenerative diseases. In this research, we investigated the effect of copper, an essential trace element for all organisms and an inducer of the reactive oxygen species, on CK refolding. It was found that trace amounts of Cu(2+) (3mol eq of Cu(2+)) could efficiently block the refolding of CK. The Cu(2+)-trapped CK could not be reactivated by the addition of EDTA, but could be reactivated by DTT. Spectroscopic experiments suggested that copper ions blocked CK refolding by specifically binding with the monomeric refolding intermediate, which further retarded CK refolding and promoted the formation of off-pathway aggregates. The results herein suggested that Cu(2+)-induced CK dysfunction might be caused not only by the post-translational oxidation, but also by the direct binding of copper ions with the newly-synthesized polypeptides.     

谈农林害虫的自然控制

人类的发展面临着许多问题,其中包括环境污染与害虫暴发失控等, 对策应是人类谋求与自然协调共存。人类必须学会既要和众多的非生命物又要和数千万种生物包括100多万种昆虫协调共存。天敌昆虫是大害虫的克星; 人类赖以生存的经济植物是由昆虫传播花粉的; 昆虫是人类的美味佳肴和医病良药; 有些昆虫是重要工业原料。所以人类要锐意合理利用昆虫资源。对于农林害虫要尽可能谋求自然控制; 提倡利用植物的抗害性、利用害虫的天敌、利用昆虫生长调节剂、种间信息物质、昆虫辐射不育技术控制害虫。尽量利用植物性杀虫剂控制害虫。尽量采用不杀伤或少杀伤天敌、不污染环境的化学杀虫剂或方法防治害虫。我国创造了很多行之有效的利用农业技术防治害虫的方法。     

Isolation of Copper Biochelates from Methylosinus trichosporium OB3b and Soluble Methane Monooxygenase Mutants

Methylosinus trichosporium OB3b produces an extracellular copper-binding ligand (CBL) with high affinity for copper. Wild-type cells and mutants that express soluble methane monooxygenase (sMMO) in the presence and absence of copper (sMMO^c) were used to obtain cell exudates that were separated and analyzed by size exclusion high-performance liquid chromatography. A single chromatographic peak, when present, contained most of the aqueous-phase Cu(II) present in the culture medium. In mutant cultures that were unable to acquire copper, extracellular CBL accumulated to high levels both in the presence and in the absence of copper. Conversely, in wild-type cultures containing 5 μM Cu(II), extracellular CBL was maintained at a low, steady level during exponential growth, after which the external ligand was rapidly consumed. When Cu(II) was omitted from the growth medium, the wild-type organism produced the CBL at a rate that was proportional to cell density. After copper was added to this previously Cu-deprived culture, the CBL and copper concentrations in the medium decreased at approximately the same rate. Apparently, the extracellular CBL was produced throughout the period of cell growth, in the presence and absence of Cu(II), by both the mutant and wild-type cultures and was reinternalized or otherwise utilized by the wild-type cultures when it was bound to copper. CBL produced by the mutant strain facilitated copper uptake by wild-type cells, indicating that the extracellular CBLs produced by the mutant and wild-type organisms are functionally indistinguishable. CBL from the wild-type strain did not promote copper uptake by the mutant. The molecular weight of the CBL was estimated to be 500, and its association constant with copper was 1.4 × 10¹⁶ M⁻¹. CBL exhibited a preference for copper, even in the presence of 20-fold higher concentrations of nickel. External complexation may play a role in normal copper acquisition by M. trichosporium OB3b. The sMMO^c phenotype is probably related to the mutant’s inability to take up CBL-complexed copper, not to a defective CBL structure.