昆虫滞育诱导的分子调控机制

滞育是昆虫长期适应不利环境的重要对策之一,对昆虫的生存、繁衍和进化都具有重要意义。滞育一般分为滞育前期、滞育期和滞育后期3个阶段,其中,滞育前期包括滞育诱导期和滞育准备期,是确保昆虫顺利进入滞育的重要时期。本文首先简要概括了光周期、温度、湿度、食料等外界环境因素在不同昆虫滞育诱导中的作用;然后系统综述了滞育激素、保幼激素、蜕皮激素、促前胸腺激素和胰岛素等内分泌激素,生物钟通路的节律基因,以及DNA甲基化、小RNA和组蛋白修饰等表观遗传修饰在昆虫滞育过程,尤其是滞育诱导调控中的作用,并以黑腹果蝇Drosophila melanogaster的生殖滞育为例,总结了昆虫滞育诱导调控的分子通路;最后就目前昆虫滞育诱导调控研究中亟待解决的问题和后续重点研究方向进行了探讨,展望了将昆虫滞育研究应用于害虫防控实践的主要策略和前景。     

保幼激素调控昆虫生殖滞育的研究进展

滞育是昆虫响应不良环境信号后的一种发育停滞的状态,是昆虫的一种季节性适应策略。生殖滞育是发生在成虫期的一种生殖系统发育停滞的滞育类型。目前普遍认为,昆虫的生殖滞育受到体内多种激素的共同调控,而其最直接的原因是保幼激素的缺乏,但其具体调控机制尚不明确。本文主要从保幼激素调控昆虫生殖滞育的下游网络及生殖滞育昆虫中调控保幼激素的上游信号两方面进行综述,以期为探明保幼激素调控昆虫生殖滞育的作用机制提供参考。     

表观遗传调控植物响应非生物胁迫的研究进展

植物的生长发育容易受到外界环境变化的影响。非生物胁迫发生时, 表观遗传机制对胁迫应答基因的表达调控发挥了十分重要的作用。近年来, 调控植物非生物胁迫应答的表观遗传机制研究取得了一系列重要进展, 为进一步深入解析植物响应非生物胁迫的分子机制奠定了基础。该文对DNA甲基化修饰、组蛋白修饰、染色质重塑和非编码RNA等主要表观遗传调控方式在植物响应非生物胁迫中的作用进行了简要综述。     

植物叶片衰老的表观遗传调控

叶片是植物重要的光合器官, 它的衰老由外界环境刺激和内源发育信号所启动, 复杂的基因调控网络参与衰老过程的精确调控。最新研究表明, 植物通过对基因表达的重编程, 在表观遗传水平上调节着叶片衰老过程。该文简要介绍了表观遗传的分子机制, 在此基础上重点综述了组蛋白修饰、染色质重塑、DNA甲基化及小RNAs途径对叶片衰老调控的最新研究进展, 同时讨论了该领域存在的问题和未来研究方向。     

社会性昆虫级型和行为分化机制研究进展

社会性的出现是生物演化过程中的重要革新, 理解社会性的演化和调控机制具有重要的理论和实际意义。社会性昆虫的个体间有着明显的级型分化和劳动分工, 这有利于它们适应复杂的环境变化。理解社会性昆虫如何产生不同的形态、行为和生活史特性, 一直是进化和发育生物学的重要目标。随着测序技术的不断更新及生物信息学的快速发展, 已经有众多关于社会性昆虫级型和行为分化机制的研究报道。本文通过整理社会性昆虫研究的已有成果, 从环境因素、生理调控和分子机制等方面对社会性昆虫级型和行为分化机制相关研究进展进行了综述, 并对未来的研究方向做出了展望。根据现有证据, 社会性昆虫所生活的生物环境(食物营养、信息素、表皮碳氢化合物)和非生物环境(温度、气候等)均能直接或间接影响社会性昆虫级型和行为的分化; 保幼激素、蜕皮激素、类胰岛素及生物胺等内分泌激素和神经激素对社会性昆虫的级型和行为分化也有重要的调控作用; 此外, 遗传因素、新基因等DNA序列或基因组结构上的变化以及表观遗传修饰、基因的差异表达等基因调控机制均能不同程度地影响社会性昆虫的行为分化。本文建议加强昆虫纲其他社会性类群如半翅目蚜虫和缨翅目蓟马等的社会性行为及其演化机制的研究, 以加深对社会性昆虫起源及其行为演化的理解和认识。     

表观遗传与microRNA相互调控机制以及在抗肿瘤领域内的应用

DNA甲基化和组蛋白修饰等表观遗传机制是恶性肿瘤发生发展的重要原因之一．然而近年来研究发现,microRNA表达水平改变也参与恶性肿瘤的形成．最新研究资料揭示,表观遗传可调控microRNA表达,而一些种类的microRNA也可调节表观遗传,并且二者之间相互作用可调控组织细胞内基因表达以及诱导体内恶性肿瘤产生．研究资料还显示,表观遗传主要通过DNA甲基化、组蛋白修饰等方式调控microRNA表达,而microRNA则通过调节DNA甲基化转移酶、维持细胞中DNA甲基化水平或改变组蛋白修饰等途径调控表观遗传．对microRNA与表观遗传之间的调控关系以及在抗肿瘤领域内的应用进行全面而系统的论述．     

高低温催青温度敏感期家蚕卵的差异蛋白筛查

滞育（Diapause）是昆虫发育停滞或减缓的生理状态，家蚕Bombyx mori作为卵滞育的代表，其滞育过程已得到广泛研究，但诱导滞育发生的分子机制尚不清楚。二化性家蚕滞育性由遗传和母系在胚胎期所处的环境条件决定，25℃催青蚕卵孵化后的家蚕产滞育卵，15℃低温催青则诱导家蚕产下非滞育卵。本研究分别用25℃和15℃催青蚕卵，在发生滞育诱导的温度敏感期取样，抽提蛋白质通过非标（Label-free）蛋白质组定量技术进行质谱测序。筛选出具有明显表达差异的蛋白104个，其中56个蛋白上调，48个蛋白下调。通过生物信息学对差异蛋白进行GO分类和KEGG功能富集分析，结果显示差异蛋白主要参与生长发育、物质代谢和胁迫应答等生物过程；同时差异蛋白主要参与胰岛素信号通路、乙醛酸和二羧酸代谢等相关途径。分别选取上调基因和下调基因进行qRT-PCR验证，其趋势与蛋白组学结果一致。该研究将为进一步解析家蚕滞育诱导发生机制提供靶标蛋白和数据参考。     

滞育昆虫营养物质的积累、转化与调控

滞育是昆虫度过不良环境的一种生存适应策略,营养物质的利用、积累和转化影响昆虫的滞育。滞育期间,昆虫体内发生一系列生理生化变化,包括脂类、碳水化合物和氨基酸等内源营养物质呈特异性地积累或转化,保障了滞育个体在逆境中存活及滞育解除后发育的能量需求。外源营养物质对昆虫滞育的影响较复杂,其种类、丰度、质量能通过"食料-寄主-天敌"营养关系进行传递,影响昆虫体内营养物质的积累和转化,改变昆虫的耐寒性、滞育率等,制约昆虫的滞育深度、滞育存活率。滞育昆虫营养物质积累、利用机制复杂多样,胰岛素信号通路-叉头转录因子以及激脂激素的调控效应在滞育诱导及营养物质转化中起到了关键的调控作用,但滞育的系统性调控仍需进一步深入研究。     

五羟色胺对昆虫取食、生殖和非遗传多型的调控

5-羟色胺广泛分布于昆虫神经系统和外围组织,调控多种生理过程和行为。研究表明,5-羟色胺可以降低昆虫取食量,促进嗉囊的收缩;5-羟色胺可以和多巴胺协同调控昆虫唾液的分泌,分别形成唾液的蛋白质和非蛋白质成分。5-羟色胺与多巴胺、保幼激素协同作用可以促进中华马蜂、美洲大蠊的卵成熟发育,还可与章鱼胺、直肠肽等协同调控多种昆虫输卵管的收缩。在昆虫生殖行为方面,5-羟色胺的调控主要表现为增强对性信息素的反应、抑制交尾后行为和维持生殖滞育。5-羟色胺通过诱导聚集行为调控蝗虫的型变,还与章鱼胺等信号分子协同调节蜜蜂、蚂蚁等社会性昆虫胚后发育和行为多型。5-羟色胺对昆虫取食、生殖及非遗传多型的调控机理还需深入研究。     

昆虫迁飞行为及其调控机制

迁飞是昆虫长期适应资源与环境的季节性变化所形成的一种行为策略.迁飞昆虫不仅通过迁飞逃避不良环境,也因其极高的繁殖力确保种群在新的生境中实现快速增长甚至暴发成灾,对整个自然生态系统和农业生态系统影响甚大.本文首先基于部分迁飞概念,描述了迁飞型和居留型个体在形态、行为、生理上的差异,重点介绍了迁飞与生殖的耦合关系,以及诱导迁飞的外界环境因子,最后综述了昆虫迁飞行为调控的分子机制方面的研究进展.从感受不良环境信号到决定迁飞,从起飞、飞行、降落到决定继续迁飞或终止迁飞,这一系列过程受昆虫内分泌、表观等诸多因素的调控,但其背后的分子机制有待深入研究.     

Epigenetics, a mode for plants to respond to abiotic stresses

Epigenetics has been becoming a hot topic in recent years.It can be mechanisms that regulate gene expression without changing DNA base sequence.In plants epigenetic regulation has been implicated to be...     

Epigenetics and cell cycle regulation in cystogenesis

The role of genetic mutations in the development of polycystic kidney disease (PKD), such as alterations in PKD1 and PKD2 genes in autosomal dominant PKD (ADPKD), is well understood. However, the significance of epigenetic mechanisms in the progression of PKD remains unclear and is increasingly being investigated. The term of epigenetics describes a range of mechanisms in genome function that do not solely result from the DNA sequence itself. Epigenetic information can be inherited during mammalian cell division to sustain phenotype specifically and physiologically responsive gene expression in the progeny cells. A multitude of functional studies of epigenetic modifiers and systematic genome-wide mapping of epigenetic marks reveal the importance of epigenomic mechanisms, including DNA methylation, histone/chromatin modifications and non-coding RNAs, in PKD pathologies. Deregulated proliferation is a characteristic feature of cystic renal epithelial cells. Moreover, defects in many of the molecules that regulate the cell cycle have been implicated in cyst formation and progression. Recent evidence suggests that alterations of DNA methylation and histone modifications on specific genes and the whole genome involved in cell cycle regulation and contribute to the pathogenesis of PKD. This review summarizes the recent advances of epigenetic mechanisms in PKD, which helps us to define the term of “PKD epigenetics” and group PKD epigenetic changes in three categories. In particularly, this review focuses on the interplay of epigenetic mechanisms with cell cycle regulation during normal cell cycle progression and cystic cell proliferation, and discusses the potential to detect and quantify DNA methylation from body fluids as diagnostic/prognostic biomarkers. Collectively, this review provides concepts and examples of epigenetics in cell cycle regulation to reveal a broad view of different aspects of epigenetics in biology and PKD, which may facilitate to identify possible novel therapeutic intervention points and to explore epigenetic biomarkers in PKD.     

A twin approach to unraveling epigenetics

The regulation of gene expression plays a pivotal role in complex phenotypes, and epigenetic mechanisms such as DNA methylation are essential to this process. The availability of next-generation sequencing technologies allows us to study epigenetic variation at an unprecedented level of resolution. Even so, our understanding of the underlying sources of epigenetic variability remains limited. Twin studies have played an essential role in estimating phenotypic heritability, and these now offer an opportunity to study epigenetic variation as a dynamic quantitative trait. High monozygotic twin discordance rates for common diseases suggest that unexplained environmental or epigenetic factors could be involved. Recent genome-wide epigenetic studies in disease-discordant monozygotic twins emphasize the power of this design to successfully identify epigenetic changes associated with complex traits. We describe how large-scale epigenetic studies of twins can improve our understanding of how genetic, environmental and stochastic factors impact upon epigenetics, and how such studies can provide a comprehensive understanding of how epigenetic variation affects complex traits.     

Queen pheromone modulates the expression of epigenetic modifier genes in the brain of honeybee workers

Pheromones are used by many insects to mediate social interactions. In the highly eusocial honeybee (Apis mellifera), queen mandibular pheromone (QMP) is involved in the regulation of the reproductive and other behaviour of workers. The molecular mechanisms by which QMP acts are largely unknown. Here, we investigate how genes responsible for epigenetic modifications to DNA, RNA and histones respond to the presence of QMP in the environment. We show that several of these genes are upregulated in the honeybee brain when workers are exposed to artificial QMP. We propose that pheromonal communication systems, such as those used by social insects, evolved to respond to environmental signals by making use of existing epigenomic machineries.     

Neural and behavioral epigenetics; what it is,and what is hype

The ability to examine epigenetic mechanisms in the brain has become readily available over the last 20 years. This has led to an explosion of research and interest in neural and behavioral epigenetics. Of particular interest to researchers, and indeed the lay public, is the possibility that epigenetic processes, such as changes in DNA‐methylation and histone modification, may provide a biochemical record of environmental effects. This has led to some fascinating insights into how molecular changes in the brain can control behavior. However, some of this research has also attracted controversy and, as is dealt with here, some overblown claims. This latter problem is partly linked to the shifting sands of what is defined as ‘epigenetics’. In this review, I provide an overview of what exactly epigenetics is, and what is hype, with the aim of opening up a debate as to how this exciting field moves forward.     

New insights into plant somatic embryogenesis: an epigenetic view

Somatic embryogenesis plays a significant role in plant regeneration and requires complex cellular, molecular, and biochemical processes for embryo initiation and development associated with plant epigenetics. Epigenetic regulation encompasses many sensitive events and plays a vital role in gene expression through DNA methylation, chromatin remodelling, and small RNAs. Recently, regulation of epigenetic mechanisms has been recognized as the most promising occurrences during somatic embryogenesis in plants. A few reports demonstrated that the level of DNA methylation can alter in embryogenic cells under in vitro environments. Changes or modification in DNA methylation patterns is linked with regulatory mechanisms of various candidate marker genes, involved in the initiation and development of somatic embryogenesis in plants. This review summarizes the current scenario of the role of epigenetic mechanisms as candidate markers during somatic embryogenesis. It also delivers a comprehensive and systematic analysis of more recent discoveries on expression of embryogenic-regulating genes during somatic embryogenesis, epigenetic variation. Biotechnological applications of epigenetics as well as new opportunities or future perspectives in the development of somatic embryogenesis studies are covered. Further research on such strategies may serve as exciting interaction models of epigenetic regulation in plant embryogenesis and designing novel approaches for plant productivity and crop improvement at molecular levels.     

Epigenetics and its implications for plant biology 2. The 'epigenetic epiphany': epigenetics, evolution and beyond

SCOPE: In the second part of a two-part review, the ubiquity and universality of epigenetic systems is emphasized, and attention is drawn to the key roles they play, ranging from transducing environmental signals to altering gene expression, genomic architecture and defence. KEY ISSUES: The importance of transience versus heritability in epigenetic marks is examined, as are the potential for stable epigenetic marks to contribute to plant evolution, and the mechanisms generating novel epigenetic variation, such as stress and interspecific hybridization. FUTURE PROSPECTS: It is suggested that the ramifications of epigenetics in plant biology are immense, yet unappreciated. In contrast to the ease with which the DNA sequence can be studied, studying the complex patterns inherent in epigenetics poses many problems. Greater knowledge of patterns of epigenetic variation may be informative in taxonomy and systematics, as well as population biology and conservation.     

重性抑郁障碍发病的表观遗传调控假说

表观遗传学是研究主要受控于DNA甲基化、染色质结构变化的可遗传和逆转的基因组功能的调控。近年来, 越来越多的证据表明表观遗传因素在精神分裂症、双相障碍、药物成瘾等重性精神障碍的发病中扮演着重要角色。文章综述了表观遗传现象的分子机制, 介绍了表观遗传修饰与复杂性疾病的关系, 并在此基础上对重性抑郁障碍(Major depressive disorder, MDD)发病的表观遗传调控假说及最新研究进展进行了总结。