鱼类肠道微生物与宿主免疫系统相互作用研究进展

鱼类肠道中存在大量微生物,对于维持宿主健康具有重要作用。鱼类免疫系统能够监视并调控肠道微生物组成,维持肠道菌群稳态。同时,鱼类肠道共生微生物调节鱼类免疫系统,抑制病原微生物的过度增殖,保证宿主的健康。本文回顾了鱼类肠道微生物与宿主免疫系统相互作用的研究进展,重点介绍了宿主免疫系统识别肠道微生物、塑造肠道菌群以及益生菌对宿主免疫和肠道菌群的调控等,提出了理想的益生菌应该来自动物自身胃肠道,生产中应谨慎选用非宿主来源的益生菌,以期为推动鱼类肠道功能微生物开发和应用提供理论支撑。     

蜜蜂肠道菌群定殖研究进展

肠道菌群在其宿主健康中发挥着各种各样的重要功能。蜜蜂是高度社会化的昆虫,其肠道菌群与大多数昆虫明显不同,由兼性厌氧和微好氧的细菌组成,具有高度保守性和专门的核心肠道微生物群。近年来的研究表明,蜜蜂肠道微生物群在代谢、免疫功能、生长发育以及保护机体免受病原体侵袭等方面起着重要作用,并已证实肠道微生物在蜜蜂健康和疾病中起着重要作用,肠道微生物群的破坏对蜜蜂健康会产生不利影响。本文综述了蜜蜂肠道菌群的特征及菌群定殖研究进展,介绍了蜜蜂的日龄、群体、季节等对蜜蜂肠道菌群定殖的影响,探讨了宿主的功能和新陈代谢对肠道菌群的影响。     

微生物-肠-脑轴的研究进展

肠道微生物群能够调节宿主肠道稳态,同时参与调节宿主神经系统功能和行为。肠道菌群失调可能导致宿主神经系统功能障碍,从而引发神经退行性疾病。因此,研究微生物在肠?脑轴中发挥的作用及其机制,靶向调控肠道微生物菌群结构和功能,将为神经系统疾病的诊断与治疗提供新的手段。近年来,有关肠道微生物与机体神经系统间的互作研究受到了广泛关注,然而其具体的调控机制还未明晰。因此,本文综述了肠道微生物对宿主神经健康的调节作用,以及肠道微生物与宿主间的互作在调节神经功能、行为的潜力等研究进展,为更好地了解肠道微生物在调控宿主神经系统功能和行为的作用机制提供参考。     

肠道菌群在蜜蜂健康与疾病中的作用研究进展

蜜蜂是重要的经济昆虫,在农作物授粉和维持生态平衡等方面扮演了重要角色。随着生态环境的逐步恶化,蜜蜂极易受到寄生虫、农药、抗生素和病原微生物等的危害。肠道作为蜜蜂的重要免疫器官,在抵抗外源刺激等方面具有不可替代的作用。而肠道菌群作为肠道的重要组成部分,对蜜蜂的健康有着至关重要的影响。其拥有高度保守和专门的核心微生物群,主要由九大类细菌组成。近年来,有关肠道菌群的研究主要集中在新陈代谢、免疫防御、生长发育等方面。肠道菌群不仅可以帮助宿主消化和制造营养素,还可维持宿主体内能量稳态,其对蛋白质的代谢也使菌群丰度增加。越来越多的证据表明,肠道菌群紊乱会导致蜜蜂健康受损,其多样性对宿主健康和疾病影响甚广。因此,肠道菌群成为近年来微生物学领域研究的焦点。主要综述了蜜蜂属、熊蜂属等主要传粉蜂类肠道菌群的组成及其在健康与疾病中的作用,为深入了解传粉昆虫肠道菌群功能提供参考。     

从肠道菌群角度认识阿尔茨海默病的潜在发病机制

过去10年中,人们逐渐认识到肠道微生物群的多样性及菌群平衡在维护宿主健康中发挥的作用。肠道微生物及其代谢产物通过一系列的生化、免疫和生理功能环节与宿主进行交流,从而影响宿主的稳态和健康。阿尔茨海默病(Alzheimer’s disease,AD)是一种复杂的神经退行性疾病,其易感性和发展过程受年龄、遗传和表观遗传等因素的影响。研究发现,肠道微生物群的紊乱(组成改变和易位)与神经系统疾病(AD)有关,胃肠道通过肠脑轴与中枢神经系统进行沟通,包括对神经的直接作用、内分泌途径和免疫调控方式。动物模型、粪便菌群移植及益生菌干预为肠道菌群与AD的相关性提供了证据。外漏的细菌代谢产物可能直接损害神经元功能,也可能诱发神经炎症,促进AD的发病。本文主要综述了肠道微生物群与AD的关联和作用机制,以期为通过改善肠道菌群结构预防AD的可能干预措施提供依据。     

昆虫肠道微生物稳态的调控机制

稳定的肠道微生物内环境是肠道微生物与肠道免疫反应相互作用的结果。在不断的进食过程中,昆虫肠道微生物种类和数量不断发生变化,肠道微生物与肠道上皮细胞之间形成了复杂的、动态的平衡机制。昆虫肠道上皮细胞可以感知有益和有害条件并利用免疫调控通路来实现微生物种群稳态的动态调节,例如双重氧化酶-活性氧(dual oxidase-reactive oxygen species, Duox-ROS)系统和免疫缺陷(immunodeficiency, Imd)信号通路可以感知肠道微生物数量变化并参与到肠道微生物稳态调节过程。除此之外,肠道微生物群也会通过群体感应(quorum sensing, QS)释放相应的效应因子来调节菌群行为,间接性起到稳态调节的作用。因此,本文综述了昆虫肠道中物理防御、免疫信号通路以及肠道微生物通过QS在昆虫肠道微生物稳态维持中的作用,加深对肠道组织与肠道微生物互作关系的认识。未来将继续对更多种类昆虫体内微生物的稳态调控机制及调控机制间的作用关系进行研究,并基于调控机制设计开发改变肠道微生物稳态的新型农药,为实现有效害虫防治提供新的靶标和思路。     

昆虫肠道菌群的功能研究进展

昆虫肠道为某些微生物提供了一个特定的定殖环境,这些肠道菌群也为其宿主提供了很多潜在的有益作用。因而昆虫在一定范围和程度上表现出对肠道菌群的依赖并形成一种互惠互利的共生关系。近年来,随着高通量测序技术的广泛应用,促进了肠道菌群及其功能基因的研究。也为进一步了解如何区分非致病性菌(共生菌)和致病菌(病原菌)的致病机理、调控昆虫肠道菌并用来防治害虫或保护授粉昆虫在内的有益昆虫奠定了基础。本文概述了昆虫肠道菌群定殖环境、起源和进化以及传播方式,综述了近年来昆虫肠道菌群功能研究的最新进展,并对今后昆虫肠道菌群的研究方向进行了展望。     

microRNA 对宿主和肠道微生物互作的调控

摘要:肠道内环境是宿主和肠道微生物菌群互作的结果,肠道菌群一方面通过抗原物质调节肠道组织的免疫稳定,另一方面,肠道菌群参与糖、脂、蛋白质代谢,产生的代谢产物能够调控细菌营养代谢、群体结构和肠道组织的营养吸收等。microRNA是宿主细胞内调控基因表达的重要因子,肠道微生物菌群不仅调控宿主mRNA的转录,同时也影响某些基因的转录后修饰。研究表明,肠道菌群通过与宿主肠道组织互作,调节肠上皮组织内某些参与炎症应答和屏障功能的microRNA 的表达。本文介绍了肠道微生物与宿主互作的基本内容,对microRNA在肠道微生物与宿主互作和肠道健康中的调节进行综述。     

肠道上皮与肠道微生物相互作用的研究现状

肠道上皮是肠上皮细胞及其分泌物有机构成的黏膜界面。随着技术的进步和对肠道菌群作用的逐渐重视,研究者对肠道上皮与肠道微生物相互作用的认识也不断深入。研究表明,肠道上皮调节并维持肠道微生物的定殖与分布,肠道微生物也影响肠道上皮的多种屏障功能,二者通过一系列细胞分子机制紧密联系,共同维持肠道稳态。此外,其过程中产生的宿主-肠道菌群共代谢物被发现可以反映宿主的生理病理状态,作为指标被应用于临床疾病诊断、治疗效果评估和预后推测。本文基于近年的研究,综述了肠道上皮与肠道微生物的相互作用及其细胞分子机制,为进一步研究和临床应用总结了理论基础,并探讨了未来可能的研究方向。     

肠道菌群：肠道干细胞增殖分化的调节者

肠道干细胞(intestinal stem cells, ISCs)是肠道各类上皮细胞的来源,通过平衡增殖与分化维持肠道稳态。同时,肠道菌群及其代谢物在维持宿主肠道稳态中也发挥着重要作用。随着技术的发展,研究者认识到ISCs与肠道菌群之间存在相互作用。研究表明,ISCs对上皮细胞亚型的调控影响肠道菌群的组成,并且肠道菌群及其代谢物也影响ISCs介导的上皮发育。本文阐述了ISCs分化对肠道菌群的影响,重点总结了肠道菌群及其代谢物调控ISCs增殖分化的研究进展,从菌群调控ISCs的角度探讨肠道损伤的治疗思路,并对未来可能的研究方向进行讨论。     

虫瘿—昆虫与植物互作的奇特产物

虫瘿是昆虫刺激产生的植物不正常组织。造瘿昆虫几乎能在高等植物的所有类群中产生形态各异的虫瘿,甚至能在同一种植物上形成多种形态不一的虫瘿。虫瘿形成的机制仍不清楚,普遍认为是昆虫控制了虫瘿的形成,但植物细胞也参与了虫瘿形成的调控。为了探索这一神秘的领域,科学家们已经对昆虫的刺激物以及植物的反应作了大量的研究,未来工作的难点将是如何把二者联系起来。     

Establishment and characterization of a cell line from embryos of the Indianmeal moth,Plodia interpunctella

A cell line, UMN-PIE-1181, initiated in November, 1981, from embryos of a malathion-resistant strain of Indianmeal moth, Plodia interpunctella, was in the 83rd passage on January 28, 1985. The line consists of single, small, fibroblastlike cells that are polyploid with chromosome numbers ranging from 56 to 180. Growth rate is dependent on seeding density, there being no growth at or below seeding densities of $\text{2 ×}\text{10}{}^5\text{5}\text{,}\text{ml}$; optimum growth requires a fetal bovine serum concentration of at least 5%. Twenty-nine isozymes were examined. Five enzymes from the cell lines resolved well and subsequently were compared to enzymes extracted from 4-day-old embryos and other life stages of the insects. Phosphomannose isomerase, malic enzyme, malate dehydrogenase, phosphoglucose isomerase, and glucose-6-phosphate dehydrogenase in extracts from the cultured cells and from the insects had identical patterns. Two bands for glutamate-oxalacetate transaminase, present in the cell line, were not observed in the tissue extracts. Furthermore, lactate dehydrogenase from the cultured cells appeared as four bands but was not detectable in any of the samples run from the various life stages of the insects.     

Plant characteristics determine insect borer assemblages on Protea species in the Cape Fynbos, and importance for conservation management

The influence of regional climate, biotope and host-plant variables on the frequency of occurrence of insect borers associated with infructescences of Protea species in the species-rich flora of the Cape Fynbos was investigated. Large samples of infructescences (n=1000) were collected on a seasonal basis and borers identified and quantified. Data were analysed using DECORANA and CANOCO so as to correlate environmental variables with borer occurrence. Distinct differences in frequency of occurrence of the various insect taxa were recorded on the various plant species studied. These differences were primarily accounted for by physical host-plant characteristics (infructescence and seed set variables), and secondarily, by biotope variables and climatic factors. Fynbos plant characteristics therefore play a major role in determining insect abundance. Plant diversity in the Fynbos is maintained by burning. These management burns, however, should not be applied too frequently or over areas large enough to extirpate any borer species. As these borers are excellent umbrellas for many other insects, their conservation covers Fynbos insect diversity in general.     

昆虫激肽的生理功能及机制

昆虫激肽是一类高度保守的小分子神经活性物质,自其从马德拉蟑螂脑中分离得到至今,人们在多种无脊椎动物体内均发现了这一激肽家族成员。它们具有促进昆虫后肠收缩、马氏管扭动、原尿分泌,调节血淋巴量和水盐平衡,使马氏管跨膜电位去极化,抑制昆虫体内消化酶释放、幼虫体重增长等功能。然而,天然的昆虫激肽很容易被蛋白酶所降解,因此须对其进行结构改造及构效关系研究,以开发出更有潜力的假肽和非肽模拟抗酶解昆虫激肽类似物,对今后实现环境友好型害虫防治策略具有重要意义。     

Effects of elevated temperature and carbon dioxide on the nutritional quality of leaves of oak (Quercus robur L.) as food for the Winter Moth (Operophtera brumata L.)

1. Pedunculate Oak trees were grown in ambient and elevated temperatures and CO₂. Leaves were fed to Winter Moth caterpillars reared either in constant conditions or with the trees (caged or on-tree).
2. Caterpillars in constant conditions ate the same mass and produced the same mass of faeces whether fed elevated or ambient temperature leaves. However, less was assimilated from elevated leaves, resulting in lighter pupae and fewer, lighter eggs.
3. Caterpillars in constant conditions ate more and produced more faeces when fed elevated CO₂ leaves than when fed ambient CO₂ leaves, but the mass assimilated and pupal mass were unchanged.
4. Caged caterpillars reared with the trees from which they were fed had constant pupal mass in all treatments, but pupated earlier at elevated temperature. Pupal mass was also unaffected when caterpillars fed on the trees.
5. Nitrogen was reduced in both elevated temperature and elevated CO₂ leaves. Increased fibre in the former prevented increased consumption and resulted in reduced pupal mass and fecundity. Reduced fibre in the latter allowed increased consumption, resulting in pupae of normal mass.
6. Despite the clear effect of nutrient quality, experiments rearing caterpillars and trees together suggest that anticipated climatic change will have no nutritional effect on Winter Moth development.     

A look into the invisible: ultraviolet-B sensitivity in an insect (Caliothrips phaseoli) revealed through a behavioural action spectrum

Caliothrips phaseoli, a phytophagous insect, detects and responds to solar ultraviolet-B radiation (UV-B; λ ≤ 315 nm) under field conditions. A highly specific mechanism must be present in the thrips visual system in order to detect this narrow band of solar radiation, which is at least 30 times less abundant than the UV-A (315–400 nm), to which many insects are sensitive. We constructed an action spectrum of thrips responses to light by studying their behavioural reactions to monochromatic irradiation under confinement conditions. Thrips were maximally sensitive to wavelengths between 290 and 330 nm; human-visible wavelengths (λ ≥ 400 nm) failed to elicit any response. All but six ommatidia of the thrips compound eye were highly fluorescent when exposed to UV-A of wavelengths longer than 330 nm. We hypothesized that the fluorescent compound acts as an internal filter, preventing radiation with λ > 330 nm from reaching the photoreceptor cells. Calculations based on the putative filter transmittance and a visual pigment template of λ_max = 360 nm produced a sensitivity spectrum that was strikingly similar to the action spectrum of UV-induced behavioural response. These results suggest that specific UV-B vision in thrips is achieved by a standard UV-A photoreceptor and a sharp cut-off internal filter that blocks longer UV wavelengths in the majority of the ommatidia.     

Vitamin C content in plants is modified by insects and influences susceptibility to herbivory

Analysis of a diverse cross‐sample of plant‐insect interactions suggests that the abundance of vitamin C (L ‐ascorbic acid, ascorbate or AsA) in plants influences their susceptibility to insect feeding. These effects may be mediated by AsAs roles as an essential dietary nutrient, as an antioxidant in the insect midgut, or as a substrate for plant‐derived ascorbate oxidase, which can lead to generation of toxic reactive oxygen species. Ascorbate can also influence the efficacy of plant defenses such as myrosinases and tannins, and alter insects' susceptibility to natural enemies. Conversely, herbivores appear to influence both de novo synthesis and redox cycling of AsA in their host plants, thereby potentially altering the nutritional value of crops and their susceptibility to pests. The recent development of genetically modified crops with enhanced AsA content provides both an impetus and a tool set for further studies on the role of AsA in plant‐insect interactions.     

Impact of urbanization on a gall-inhabiting Lepidoptera assemblage: the importance of reserves in urban areas

This paper examines the structure of a Lepidoptera assemblage in an urban environment in South Africa. The Lepidoptera inhabit fungus-induced galls on Acacia karroo. Habitat patches supporting the moth assemblage were sampled from rural, urban-reserve, suburban and city sites and the habitat quality at each of these sites was quantified. Gall occupancy, larval density and species richness were lowest at the most disturbed, city sites. Non-parametric multivariate techniques showed that the moth-assemblage structure did not differ significantly at rural and urban-reserve sites. Assemblage structure at the suburban sites was variable and appeared to be transitional in structure between the city assemblage and the rural and urban-reserve assemblages. Habitat quality variables however were weakly correlated with moth-assemblage structure. The contribution of urban reserves to the local sustainability of this Lepidoptera assemblage emphasizes the importance of maintaining green areas in and around cities.     

Insect cells as hosts for the expression of recombinant glycoproteins

Baculovirus-mediated expression in insect cells has become well-established for the production of recombinant glycoproteins. Its frequent use arises from the relative ease and speed with which a heterologous protein can be expressed on the laboratory scale and the high chance of obtaining a biologically active protein. In addition to Spodoptera frugiperda Sf9 cells, which are probably the most widely used insect cell line, other mainly lepidopteran cell lines are exploited for protein expression. Recombinant baculovirus is the usual vector for the expression of foreign genes but stable transfection of - especially dipteran - insect cells presents an interesting alternative. Insect cells can be grown on serum free media which is an advantage in terms of costs as well as of biosafety. For large scale culture, conditions have been developed which meet the special requirements of insect cells.With regard to protein folding and post-translational processing, insect cells are second only to mammalian cell lines. Evidence is presented that many processing events known in mammalian systems do also occur in insects. In this review, emphasis is laid, however, on protein glycosylation, particularly N-glycosylation, which in insects differs in many respects from that in mammals. For instance, truncated oligosaccharides containing just three or even only two mannose residues and sometimes fucose have been found on expressed proteins.These small structures can be explained by post-synthetic trimming reactions. Indeed, cell lines having a low level of N-acetyl--glucosaminidase, e.g. Estigmene acrea cells, produce N-glycans with non-reducing terminal N-acetylglucosamine residues. The Trichoplusia ni cell line TN-5B1-4 was even found to produce small amounts of galactose terminated N-glycans. However, there appears to be no significant sialylation of N-glycans in insect cells. Insect cells expressed glycoproteins may, though, be 1,3-fucosylated on the reducing-terminal GlcNAc residue. This type of fucosylation renders the N-glycans on one hand resistant to hydrolysis with PNGase F and on the other immunogenic. Even in the absence of 1,3-fucosylation, the truncated N-glycans of glycoproteins produced in insect cells constitute a barrier to their use as therapeutics. Attempts and strategies to mammalianise the N-glycosylation capacity of insect cells are discussed.     

苹果蠹蛾的综合防控和遗传控制研究进展

苹果蠹蛾是仁果类水果的重要检疫害虫,在世界各地造成了巨大的经济损失。目前对其化学防治、化学生态调控、病毒等防治方法研究较多,但仍不能满足防控该害虫的需要,对新型防控技术的需求日益增强。不育昆虫释放技术(SIT)是一种可控制甚至根除靶标害虫的环境友好型防控技术,但传统SIT技术存在一定的局限性,如较难区分性别与筛选雌雄虫、辐射不育昆虫的交配竞争力和适合度降低等问题,这些缺陷随着昆虫遗传修饰技术的发展将得以解决,并将在害虫防控进程中起到积极作用。本文综述了苹果蠹蛾主要防控技术研究现状,介绍了通过遗传修饰技术改善SIT的技术策略,并综合分析了我国开展苹果蠹蛾遗传修饰研究情况和将其应用在苹果蠹蛾防控体系中的可行性及优势。