沃尔巴克氏体Wolbachia对宿主的生殖调控作用及其研究进展

沃尔巴克氏体Wolbachia是广泛分布于节肢动物体内的共生微生物,可通过宿主卵的细胞质传递给子代。Wolbachia通过多种方式调控其宿主的生殖活动,包括细胞质不亲和、孤雌生殖、雌性化、杀雄性和增强雄性或雌性的生殖力。通过这些调控作用促进其在宿主种群内的广泛传播。文章简要综述Wolbachia对宿主的生殖调控作用、水平传播、Wolbachia基因和应用方面的研究。     

舟山附近海域富营养化的时空分布及其与环境因子的关系

根据2008年春季(5月)和夏季(8月)在舟山附近海域调查监测资料,采用改良后的营养指数法,结合N/P(物质的量比)潜在性富营养化法,对该海域在春季和夏季的富营养化水平进行了评价,并分析了该海域富营养化的时空分布特征,对富营养化指数与环境因子的相关关系进行了讨论,同时对两种方法的结果进行了比较分析.营养指数法计算结果显示:舟山附近海域的富营养化程度较低,各调查站位富营养化指数均小于富营养化阀值;春季的富营养化水平高于夏季;春季、夏季富营养化指数的平面分布均表现出沿岸到离岸方向呈逐渐降低的特点;春季调查海域N/P平均值为17.35,略高于Redfield系数,夏季N/P平均值为56.34,具有明显的营养盐比例不平衡的特征.潜在性富营养化法计算结果显示:春季属于富营养水平,夏季属于磷限制潜在性富营养;富营养化指数与盐度、溶解氧、pH相关性均不显著,调查海域富营养化水平的时空变化主要受地表径流冲谈水、浮游植物、外海海流等的共同影响.     

西辽河平原不同利用条件下羊草无性系种群结构的研究

1　引　　言羊草 (Ｌｅｙｍｕｓｃｈｉｎｅｎｓｉｓ(Ｔｒｉｎ .)Ｔｚｖｅｌ.)是典型的无性系根茎禾草 ,营养繁殖力强 ,在我国内蒙古东部和东北西部以及黄土高原地区的天然草地有广泛分布 .羊草具有很高的营养价值 ,是我国优良的牧草之一 ,多年来一直是草地学和生态学工作者研究的热点 ,并已开展到生物学的各个层次水平[1～ 3 ,8] .但对羊草无性系种群的研究较少 ,主要集中在年龄结构及营养繁殖特性等方面[4～ 7] .本文以天然草地灰绿型和黄绿型羊草种群为研究对象 ,对种群在不同干扰地段的变化进行了现实种群与潜在种群年龄结构的分析 ,为羊…     

山西云蒙山油松种群的年龄结构和动态特征

本文用样方法研究了山西云蒙山油松种群的年龄结构、存活曲线和数量动态规律,并且讨论了油松种群数量动态和群落演替的关系,结果表明:油松种群具有增长型和衰退型的动态特征,影响油松种群数量的内在机制主要是种内光资源的竞争。尽管大多数油松种群处于不断衰减状态,但其群落结构及性质在较长时期内将不会发生显著的变化。     

中国南方双斑长跗萤叶甲地理种群遗传结构及Wolbachia感染

[目的]双斑长跗萤叶甲Monolepta hieroglyphica为多食性害虫,可取食为害多种农作物.本研究旨在探究中国南方地区分布的双斑长跗萤叶甲地理种群的遗传多样性、遗传结构及种群间的遗传分化程度与基因流水平,探究共生菌Wolbachia 在中国南方双斑长跗萤叶甲地理种群中的多样性和感染情况.[方法]以线粒体CO...     

Wolbachia与昆虫寄主关系研究进展

Wolbachia pipientis是一种广泛存在于节肢动物和线虫生殖组织中的细胞内共生菌,通过母系生殖细胞在寄主种群内垂直传播。据分析,Wolbachia在昆虫中的感染率大约为66%,是昆虫中分布最广泛的胞内共生菌。Wolbachia能够以多种方式调控寄主的生殖行为,包括诱导细胞质不亲和、诱导孤雌生殖、雌性化、杀雄作用等。近10年来,Wolbachia的研究在多个领域都取得了长足进展。本文介绍了Wolbachia的多样性与分布、对寄主生殖行为的影响、基因组结构,以及其与寄主在基因组水平上的相互作用等领域的最新研究成果,并展望了Wolbachia研究的发展趋势。     

Endosymbiotic Wolbachia bacteria as biological control tools of disease vectors and pests

Wolbachia bacteria are common cytoplasmic symbionts of insects, mites and filarial nematodes. They can alter the reproduction of their hosts. The symbiont could be eliminated, transferred or used through genetic alteration to take advantage or remove their possible influences on pests and/or natural enemies. Their extensive effects on reproduction and host fitness have made Wolbachia the subject of growing attention as a potential biocontrol agent. Here, we summarize the relations of Wolbachia in the control of disease vectors and pests. Furthermore, the drawbacks of these bacteria are also discussed.     

共生菌Wolbachia引起宿主细胞质不亲和的研究进展

Wolbachia 是一类广泛存在于节肢动物以及线虫体内细胞质中呈母系遗传的共生细菌,能够在宿主中产生细胞质不亲和、孤雌生殖、雌性化及杀雄等多种生殖调控作用,其中细胞质不亲和是指被 Wolbachia 感染的雄性个体与未感染的雌性个体（单向不亲和）,或者感染不同株系 Wolbachia 的雌性个体（双向不亲和）交配后不能或很少产生后代,或者后代偏雄性的现象。细胞质不亲和作用使感染的雌性个体在种群中具有很大的生殖优势,凭借这种生殖优势,Wolbachia 能够迅速在宿主种群中扩张。细胞质不亲和的机理探索主要集中在细胞学水平上,其中广为接受的精子“修饰”和“拯救”理论认为,精巢中的 Wolbachia 能够修饰宿主的精细胞,使其不能和卵细胞正常融合,但是当母本感染相同的 Wolbachia 时,就能够将“修饰”过的精子细胞“拯救”过来,使其恢复与卵细胞的正常融合。而分子机理上的探索也开始在转录组、基因组和miRNA水平上对部分昆虫展开了研究。影响细胞质不亲和的因素有很多,包括宿主遗传背景、 Wolbachia 株系、Wolbachia 基因型、共生菌密度（浓度、滴度）、雄虫年龄、环境因素以及共生菌在宿主生殖组织的分布等。近年来,人类也应用细胞质不亲和控制害虫（主要是蚊虫）和人类疾病,取得了较好的进展。     

Genetic structure of sibling butterfly species affected by Wolbachia infection sweep: evolutionary and biogeographical implications

It was recently recognized that in Japan, the common yellow butterfly, Eurema hecabe, consists of two sibling species, which have been unnamed yet and tentatively called yellow (Y) type and brown (B) type. We investigated the diversity of nuclear and mitochondrial genes in Japanese populations of Y type and B type of E. hecabe. The phylogeny based on nuclear genes agreed with the distinction between Y type and B type, which had been also supported by a wide array of biological data. However, the phylogeny based on mitochondrial genes did not reflect the distinction. PCR survey of Wolbachia revealed that B-type populations were all infected while Y-type populations contained both infected and uninfected individuals. A single genotype of Wolbachia, which was inferred to be a CI-inducing strain from their wsp gene sequence, was prevalent in these populations. Notably, the mitochondrial phylogeny was in perfect agreement with the pattern of Wolbachia infection, suggesting that the Wolbachia infection had affected the mitochondrial genetic structure of the host insects. Probably, the Wolbachia strain and the associated mitochondrial genomes have been occasionally introduced from B-type populations to Y-type populations through migration and subsequent interspecific hybridization, and CI-driven population sweep has been spreading the Wolbachia strain and the particular mitochondrial haplotypes, which originated from B-type populations, into Y-type populations. On the basis of these results together with the geological and biogeographical knowledge of the Japanese Archipelago, we proposed an evolutionary hypothesis on the invasion and spread of Wolbachia infection in B-type and Y-type of E. hecabe.     

Wolbachia属共生细菌及其对节肢动物生殖活动的调控作用

Wolbachia属是广泛分布于节肢动物生殖组织内的一类共生细菌。这些共生菌通过卵的细胞质传播并参与多种调控其宿主生殖活动的机制,包括:诱导生殖不亲和、诱导孤雌生殖、雌性化、雄性致死和调节繁殖力。Wolbachia被认为与性别决定、共生关系和物种形成等重要生物学问题密切相关,是探索这些研究领域的新线索。而且Wolbachia可作为特定的载体对其宿主种群进行遗传调控,如增强寄生蜂在害虫生物防治中的作用,控制线虫引起的疾病传播。该文综述了Wolbachia的形态学及存在部位、基因组结构、系统发育、种的命名、水平传递和Wolbachia对其宿主生殖活动的调控作用,并分析了Wolbachia研究的科学意义和发展趋势,以期引起我国生物学家对Wolbachia研究的注意和快速切入。     

High levels of multiple Wolbachia infection and recombination in the ant Formica exsecta

Wolbachia bacteria are intracellular symbionts of many arthropod species. Their spread through host populations is promoted by drastic alterations imposed on their hosts' reproductive physiology. In the present study, we analyzed the association between Wolbachia strains and host mitochondrial haplotypes in a Swiss population of the ant Formica exsecta. In this species, female dispersal is extremely limited and the mitochondrial haplotypes are strongly differentiated between and within subpopulations. Our study revealed exceptionally high levels of multiple infection, with all ants harboring four or five distinct Wolbachia strains. Four of these strains were present in all ants analyzed. A fifth strain was associated with only three of the five mitochondrial haplotypes. An analysis of the Wolbachia gene wsp further revealed an unexpected high rate of recombination, with three of the five Wolbachia strains appearing to have arisen by homologous recombination.     

贵州青岩油杉种群年龄结构和动态的研究

研究了青岩油杉种群年龄结构的类型,动态规律及其与群落演替和环境之间的相互关系。结果表明,青岩油杉种群年龄结构有增长型,稳定型,始衰型和中衰型4类,存活曲线呈现凹型,凸型,间断型和散点型,随着群落的发育和演替,青岩油杉种群年龄结构的变化趋势为增长型→稳定型→衰退型→残留型。青岩油杉本身的生物生态学特性,群落内阔叶树的发展,地理隔离,人为干扰等是影响青岩油杉种群年龄结构及其动态变化的重要因素。     

Wolbachia对苹果蠹蛾生殖调控的作用

【背景】苹果蠹蛾是重要的果树害虫和检疫对象。研究显示,苹果蠹蛾体内所含的Wolbachia属于具有诱导胞质不亲和(CI)现象的A组中Dor亚组。本研究目的在于摸清苹果蠹蛾体内的Wolbachia对宿主的生殖调控是否具有诱导胞质不亲和的功能。【方法】通过饲喂抗生素消除苹果蠹蛾体内的Wolbachia,比较感染与消除Wolbachia的苹果蠹蛾生态适合度以及Wolbachia感染对苹果蠹蛾生殖的影响。【结果】消除Wolbachia后,苹果蠹蛾F_1、F_2代各虫态的发育历期、产卵量、孵化率和蛹的存活率与对照无显著差异;Wolbachia对苹果蠹蛾成虫的寿命、产卵前期、平均产卵量和性别比例均无影响。不同处理苹果蠹蛾之间的杂交试验结果表明,4种杂交的苹果蠹蛾都能产卵,且卵可以正常孵化。【结论与意义】在自然状态下苹果蠹蛾体内的Wolbachia不能诱导其宿主的胞质不亲和现象。     

独叶草种群年龄结构及动态分析

对太白山不同生境条件下的独叶草种群年龄结构、生命表及存活曲线进行了研究,结果表明,不同生境的独叶草种群在3～6年生阶段个体数量最多。幼年个体和老年个体数量较少,生命表中。幼龄级的dx、qx、Kx等为负数,可以反映种群幼龄个体缺乏程度．以无性繁殖独叶草不同与以有性生殖为主的植物,它可产生不同龄级的无性系分株,幼龄个体少的年龄结构并不代表种群必然衰退．随海拔升高,种群密度增加,个体寿命延长,反映了种群在适应性方面的调整．独叶草种群根状茎生存于腐殖质层中,仅有叶片露出地面;种群所在的牛皮桦、巴山冷杉和太白红杉群落人为干扰较少。生境相对稳定,种群可以长期维持．对种群保护应注重所处的环境及森林群落保护。     

Existence and stability of equilibria in age-structured population dynamics

The existence of positive equilibrium solutions of the McKendrick equations for the dynamics of an age-structured population is studied as a bifurcation phenomenon using the inherent net reproductive rate n as a bifurcation parameter. The local existence and uniqueness of a branch of positive equilibria which bifurcates from the trivial (identically zero) solution at the critical value n=1 are proved by implicit function techniques under very mild smoothness conditions on the death and fertility rates as functional of age and population density. This first requires the development of a suitable linear theory. The lowest order terms in the Liapunov-Schmidt expansions are also calculated. This local analysis supplements earlier global bifurcation results of the author. The stability of both the trivial and the positive branch equilibria is studied by means of the principle of linearized stability. It is shown that in general the trivial solution losses stability as n increases through one while the stability of the branch solution is stable if and only if the bifurcation is supercritical. Thus the McKendrick equations exhibit, in the latter case, a standard exchange of stability with regard to equilibrium states as they depend on the inherent net reproductive rate. The derived lower order terms in the Liapunov-Schmidt expansions yield formulas which explicitly relate the direction of bifurcation to properties of the age-specific death and fertility rates as functionals of population density. Analytical and numerical results for some examples are given which illustrate these results.     

节肢动物内共生菌Wolbachia的研究进展

沃尔巴克氏体Wolbachia为母系传播的胞内共生菌,可通过对宿主产生多种调控方式扩大其自身在宿主种群的传播。据推测,有40%~60%的节肢动物都感染有Wolbachia,并可根据不同株系间的系统发育关系将其分为多个超群。为了有助于深入研究Wolbachia对其宿主的调控方式及其调控机制及提出更为有效的害虫生物防治策略,本文综述了节肢动物内共生菌Wolbachia的研究现状。1924年Wolbachia被报道首次发现于尖音库蚊Culex pipiens的生殖组织中,1971年确认其与宿主的胞质不亲和现象有关。Wolbachia可以通过胞质不亲和、杀雄、雌性化、孤雌生殖等作用方式调控宿主的生殖。除生殖调控之外,Wolbachia对宿主的调控方式还包括调控宿主新陈代谢、抵制病原菌、影响宿主生殖力等。Wolbachia调控的胞质不亲和现象可用“修饰-营救”(modification-rescue)模型解释,且已有与Wolbachia诱导宿主胞质不亲和相关的功能基因被报道。wMel株系是首个公布全基因组序列的Wolbachia株系,随后又有数十种不同株系的Wolbachia基因组陆续被破译。wMel株系Wolbachia可起到抑制登革热病毒传播的作用;同时,Wolbachia和昆虫不育技术的结合对白纹伊蚊Aedes albopictus野外种群起到良好的控制效果。鉴于目前节肢动物内共生菌Wolbachia的研究现状,我们认为未来应开展以下研究：(1)Wolbachia基因组及生殖调控作用关键功能基因的研究;(2)Wolbachia与宿主间互作机制的研究;(3)Wolbachia在生物防治方面的应用。     

节肢动物内共生菌Wolbachia的研究进展

沃尔巴克氏体Wolbachia为母系传播的胞内共生菌,可通过对宿主产生多种调控方式扩大其自身在宿主种群的传播。据推测,有40%~60%的节肢动物都感染有Wolbachia,并可根据不同株系间的系统发育关系将其分为多个超群。为了有助于深入研究Wolbachia对其宿主的调控方式及其调控机制及提出更为有效的害虫生物防治策略,本文综述了节肢动物内共生菌Wolbachia的研究现状。1924年Wolbachia被报道首次发现于尖音库蚊Culex pipiens的生殖组织中,1971年确认其与宿主的胞质不亲和现象有关。Wolbachia可以通过胞质不亲和、杀雄、雌性化、孤雌生殖等作用方式调控宿主的生殖。除生殖调控之外,Wolbachia对宿主的调控方式还包括调控宿主新陈代谢、抵制病原菌、影响宿主生殖力等。Wolbachia调控的胞质不亲和现象可用“修饰-营救”(modification-rescue)模型解释,且已有与Wolbachia诱导宿主胞质不亲和相关的功能基因被报道。wMel株系是首个公布全基因组序列的Wolbachia株系,随后又有数十种不同株系的Wolbachia基因组陆续被破译。wMel株系Wolbachia可起到抑制登革热病毒传播的作用;同时,Wolbachia和昆虫不育技术的结合对白纹伊蚊Aedes albopictus野外种群起到良好的控制效果。鉴于目前节肢动物内共生菌Wolbachia的研究现状,我们认为未来应开展以下研究：(1)Wolbachia基因组及生殖调控作用关键功能基因的研究;(2)Wolbachia与宿主间互作机制的研究;(3)Wolbachia在生物防治方面的应用。