寄生蜂调控寄主害虫免疫与发育机理的研究新进展

寄生蜂是重要且种类最为丰富的膜翅目昆虫类群之一,也是极具价值的害虫生物控制因子。寄生蜂携带有不同类型的活性因子,包括毒液、多分DNA病毒类病毒颗粒、卵巢蛋白、畸形细胞及幼虫分泌物等,用于调控寄主害虫的免疫反应、发育等重要生理过程,以确保成功寄生并确保其子代在寄主害虫体内(内寄生蜂)或体表(外寄生蜂)正常发育,最终可导致寄主害虫死亡,从而有效控制寄主害虫种群数量。目前已有诸多与寄生蜂调控寄主害虫内在机理相关的研究报道,该领域也已成为昆虫寄生学与生理学的研究热点之一。本文仅从寄生蜂寄生因子多样性、寄生蜂调控寄主害虫免疫及发育的机理等方面,对相关的最新研究进展作一概述。     

寄生蜂取食寄主特性及其在害虫生物防治中的作用

许多寄生性天敌昆虫的雌虫不仅寄生寄主, 而且还能取食寄主。在卵育型（synovigenic）寄生蜂类群中, 取食寄主行为是较为普遍的现象。本文综合近20年相关研究进展, 从寄生蜂类群、取食类型、生态学意义及影响因子等方面对寄生蜂的取食寄主行为进行了归纳总结。寄生蜂通过取食不仅可以杀死寄主, 直接起到控制害虫种群数量的作用, 还能通过取食策略为卵的成熟和再生提供营养来源, 对延长雌虫的寿命也有一定的帮助。对取食寄主行为的了解可为筛选优势寄生性天敌种类、评估寄生蜂在害虫生物防治中的作用提供重要信息。     

寄生蜂抗药性研究进展

植物-植食性昆虫-寄生蜂三级营养结构之间由于长期相互适应和协同进化,产生了一系列独特的相互关系。选择压力将对害虫和寄生蜂的抗药性演化产生影响,但由于寄生蜂具有与植食性昆虫不同的生物学及生态学特性,选择压力对害虫和寄生蜂抗药性演化的影响作用也是不同的。研究结果表明,除体外杀虫剂对寄生蜂的直接汰选因素外,进入寄主昆虫体内的杀虫剂成分、寄主昆虫取食不同植物的特有成分以及气候因子等均会对寄生蜂的抗药性演化产生影响。     

寄生蜂寻找隐蔽性寄主害虫的行为机制

林木蛀干类害虫具有高度的隐蔽性,是林业上的一类重要害虫,也是目前世界上最难防治的害虫类群之一.寄生蜂在与寄主长期的协同进化过程中,形成了搜索、发现和攻击寄主害虫的独特机制,能够有效地找到并寄生它们.总结了寄生性天敌寻找、发现并成功定位隐蔽性寄主害虫的行为学机制.寄生蜂可以利用来自嗅觉的化学信息物质(如寄主、寄主粪便、虫道共生菌的挥发性气味)、寄主成虫的化学通讯物质、来自视觉的植物表面色差信息、来自触觉的寄主保护物性状特征、来自寄主取食和运动所产生的介质振动信号以及来自寄主活动和代谢的红外辐射等多种途径有效地发现隐蔽性害虫的位置,从而完成寄生行为.有些寄生蜂还能综合利用来源不同的多种信息,从而提高寄主定位的可靠性和准确性.本文还对寄生蜂寻找寄主的这些线索在生物防治上可能的利用途径和前景进行了讨论.这对促进我国在该领域的研究,充分利用天敌昆虫,提高生物防治效率具有参考价值.     

生物因子对寄生蜂滞育的影响

在影响寄生蜂滞育的生物因子中,寄主及亲代是主要影响因子。寄主可以从种类、类型、生理状态及丰富度等方面影响寄生蜂的滞育:寄生不同种类的寄主,寄生蜂的滞育反应、滞育进度、滞育比例以及光周期反应表现等均有不同;寄主类型的影响在蚜茧蜂类群中表现最为突出,不同寄主类型能对蚜茧蜂的滞育诱导产生不同影响;此外,寄主生理状态和寄主丰富度也是影响寄生蜂滞育的重要因子。亲代对寄生蜂滞育的影响则通过其所经历的环境条件以及自身因素等方面来表现:亲代经历的光周期和温度等能显著影响子代的滞育,甚至起完全决定作用;在亲代自身因素的影响中,亲代虫龄差异是主要因素。本文同时对寄生蜂滞育的研究及应用前景也一并作了展望。     

寄生蜂感受器的结构和功能研究进展

寄生蜂是寄生在寄主体内或体外的一类重要天敌昆虫,在农林害虫生物防治中具有重要作用.寄生蜂对寄主的确定主要依靠触角敲打和产卵器刺探共同完成,作为寄生蜂的重要感觉器官,触角和产卵器上着生有不同种类的感受器,在其寄主搜寻和产卵识别等过程中起着感受外界信息的关键作用.本文综述了国内外有关寄生蜂触角和产卵器上感受器的研究进展,包括感受器的类群划分、超微结构和生理功能等方面,并对该领域中尚待解决的问题和研究展望进行了探讨,以期为深入研究寄生蜂的寄生行为,揭示其对外界信息的感受机制以及将来利用寄生蜂进行害虫的生物防治提供理论基础.     

取食对寄生蜂的影响

寄生蜂是调节昆虫种群动态的重要因子之一,其对寄主害虫产生影响的因素主要有寄生蜂摄入的营养、寄生蜂的寿命和生殖力以及其对寄主的搜寻效率等.寄生蜂的营养主要来源于幼蜂体内营养积累和成蜂取食两个途径.其中成蜂取食又包括取食寄主和取食非寄主食物两个方面.某些种类的成蜂通过取食寄主来获得生存和生殖所需的营养,但是大部分成蜂需要取食糖类来作为其主要能源,而且糖类对寄生蜂的生存和生殖也会产生一定的影响.本文综述了寄生蜂的食物来源、食物营养在寄生蜂体内的分配、取食寄主和非寄主食物对寄生蜂的影响以及寄生蜂在寄主搜寻和非寄主食物搜寻之间的权衡,以期为寄生蜂的饲养和利用提供参考.     

寄生蜂调控半翅目害虫粉虱和蚜虫生理机制的研究进展

半翅目粉虱和蚜虫是农业上两类最重要的害虫之一,可为害多种农作物、蔬菜、经济作物等,并在全球范围内对农业生产造成严重的经济损失。寄生蜂作为一类种类繁多、寄生率高且对环境无威胁的天敌昆虫,在以生物防治为主的粉虱、蚜虫的绿色防控中发挥了极为重要的控害作用。近年来,随着对寄生蜂研究的不断深入,人们更加迫切了解寄生蜂对寄主的作用机制。目前,对以果蝇为代表的模式物种以及鳞翅目昆虫及其寄生蜂的研究较为完善,而对其他目害虫寄生蜂的调控机制认识较少。文章以半翅目害虫粉虱、蚜虫和其寄生蜂为研究对象,从免疫系统、生长发育以及能量代谢3个方面对寄生蜂调控寄主的生理机制进行了综述,以期为半翅目害虫的寄生蜂研究提供一定的建议和参考。     

基于组学的寄生蜂与寄主免疫的相互作用

寄生蜂作为天敌昆虫,在害虫生物防治中起着极其重要的作用。现代分子生物学和第二代测序技术的迅速发展,为筛选寄生蜂与寄主免疫互作的关键分子,阐明寄生蜂逃避或抑制寄主免疫系统攻击的机理提供了新的机遇。昆虫的天然免疫可分为细胞免疫和体液免疫,寄生蜂在与寄主长期的协同进化过程中,依靠毒液(venom)、多分DNA病毒(PDV)、类病毒颗粒(VLP)、畸形细胞(teratocyte)等手段,一方面调控寄主血细胞的增殖和分化,抑制细胞包囊反应,从而破坏寄主的细胞免疫系统;另一方面,通过抑制酚氧化酶原激活干扰寄主的体液免疫,从而逃避黑化反应的攻击。寄生蜂在发育过程中也有相应的免疫防御机制。本文从细胞免疫、体液黑化反应以及免疫信号通路等方面,综述了近年来利用组学手段在寄生蜂调控寄主免疫方面取得的最新进展,以期为阐明天然免疫的分子机制、探索害虫防治新方法提供借鉴。     

蝶蛹金小蜂的卵巢发育在不同寄主之间差异性的比较

为明确不同寄主对蝶蛹金小蜂Pteromalus puparum卵巢发育的影响,以柑橘凤蝶Papilio xuthus和菜粉蝶Pieris rapae这两种常见的寄主为研究对象,调查了两种寄主对蝶蛹金小蜂卵巢管长度、不同发育级别卵的卵室数,以及各自占整个卵巢卵室总数的比例进行了调查.结果表明,从两种寄主中羽化出的寄生蜂在卵巢管长度间差异显著,而在Ⅲ级卵的卵室比例上以柑橘凤蝶为寄主的寄生蜂明显高于以菜粉蝶为寄主的寄生蜂,而Ⅰ级和Ⅱ级的卵比例则低于后者.     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

New amino-dithiaphospholanes and phosphoramidodithioites and their rhodium and iridium complexes

New sulfur derivatives of phosphoramidite ligands were synthesized and the impact of the sulfur unit on the spectroscopic properties of their rhodium and iridium complexes was investigated. The new ligands Bn₂NPSCH₂CH₂S^a(P-S^a) (Bn = benzyl, 4), Bn₂NPSCHCHS^a(CH₂)₃C^aH₂(P-S^a)(C^a-S^a) (6) and Bn₂NP(4-XC₆H₄OMe)₂ (X = S, 7a; X = O, 7b) were converted to the rhodium and iridium complexes trans-[Rh(CO)Cl(L)₂] (L = 4, 6, 7), [RhCl(COD)(L)] (L = 4, 6, 7), [IrCl(COD)(7a)] and [IrCl₂Cp∗(6)]. For comparison, some phosphoramidite complexes of these formulations also were synthesized. The new metal complexes were spectroscopically analyzed. For the carbonyl complexes, the ν_CO IR stretching frequencies were lower than for the corresponding phosphite and phosphoramidite ligands. The ¹J_PRh coupling constants for the rhodium complexes with the new ligands were also smaller than for the respective phosphoramidite and phosphite complexes. Finally, the ¹J_PSe coupling constants of the selenides of the new ligands were lower than those of the phosphoramidite ligands but higher than for PPh₃. The spectroscopic data reveal that the new thio ligands 4, 6 and 7a are more electron donating than phosphites and phosphoramidites but less electron donating than PPh₃.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.     

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.     

Prostaglandin and thromboxane production by human and guinea-pig macrophages and leucocytes

The ability of partially purified human and guinea-pig haematogenous cell populations, when cultured in vitro, to metabolise arachidonic acid (AA) has been studied. Supernatants from 24 hour cell culture have been subjected to analysis for products of AA metabolism by gas chromatography with electron-capture detection.The cell types studied were human peripheral blood monocytes (both glass adherent and non-adherent), neutrophils, eosinophils and leukemic leucocytes; thoracic duct lymphocytes and lung alveolar macrophages. From the guinea-pig, induced and non-induced macrophage or neutrophil enriched peritoneal exudate populations, lymph node cells, peritoneal eosinophils and peripheral blood platelets were examined. Supernatants were assayed for the presence of PGE₂, PGD₂, PGF_2α, TXB₂ and 6-keto-PGF_1α. In all types studied PGE₂ and TXB₂ were the major products formed. The identification of PGE₂ and TXB₂ was confirmed by GC/MS with multiple ion monitoring.The results have been compared with other reports and their possible significance discussed in relation to the proposed role of prostaglandins as mediators and modulators in immunopathology.     

Chemokines and cytokines: axis and allies in asthma and allergy

Allergic asthma can be precipitated by many factors. For the atopic person, fungus, pollen, dust mites, cockroach antigens, and diesel exhaust are all agents that may trigger an allergic attack. Cytokines and chemokines are integral mediators of fungal asthma. From the earliest time points, they recruit and activate the cells required for the clearance of fungus as well as being critical factors involved in the immunopathology of this disease. In the final analysis, it is clear that these mediators can act to the benefit or the detriment of the host.     

Oxidation and nitration of ribonuclease and lysozyme by peroxynitrite and myeloperoxidase

In spite of the many studies on protein modifications by reactive species, knowledge about the products resulting from the oxidation of protein-aromatic residues, including protein-derived radicals and their stable products, remains limited. Here, we compared the oxidative modifications promoted by peroxynitrite and myeloperoxidase/hydrogen peroxide/nitrite in two model proteins, ribonuclease (6Tyr) and lysozyme (3Tyr/6Trp). The formation of protein-derived radicals and products was higher at pH 5.4 and 7.4 for myeloperoxidase and peroxynitrite, respectively. The main product was 3-nitro-Tyr for both proteins and oxidants. Lysozyme rendered similar yields of nitro-Trp, particularly when oxidized by peroxynitrite. Hydroxylated and dimerized products of Trp and Tyr were also produced, but in lower yields. Localization of the main modified residues indicates that peroxynitrite decomposes to radicals within the proteins behaving less specifically than myeloperoxidase. Nitrogen dioxide is emphasized as an important protein modifier.