枣树全基因组MITEs成分分析与系统进化研究

微型反向重复转座基因(minialure inverted repeat transposable elements,MITEs)的演化可能是造成枣树基因组及品种多样性的重要原因.为研究MITEs在枣树全基因组中的分布、种类及演化,使用MITE预测软件(MITEDigger)识别枣树全基因组中的MITEs序列,在植物MITEs数据库中进行分类注释,并用MEGA 6.0构建枣树基因组中MITEs的系统进化树.结果显示,MITE-Digger检测出MITEs总共3 230条,碱基数为1 104 679 bp,占基因组比例为0.34%;其中共有948条在植物MITEs数据库中比对到相似序列,这些MITEs可以归类到5个家族:h AT,PIF/Harbinger,CACTA,Mutator和Tc1/Mariner,MITEs系统进化树显示:枣树基因组中MITEs来源于少数几个共同祖先,在长期的进化中有明显的扩增和突变,这可能与枣树品种多样性有关.研究结果将为枣树的遗传资源及育种研究提供重要参考.

植物MITEs转座子及其应用

转座子是存在于染色体DNA上可自主复制和位移的基本单位。简单介绍了转座子的种类、结构和特性,综述了MITEs转座子的研究进展及其应用。

蓖麻基因组中一种Mutator-like类型MITEs元件的结构分析和鉴定

利用生物信息学方法,对蓖麻基因组Mutator-like类型MITEs元件进行了分析和鉴定。结果表明,蓖麻基因组上共鉴定出76个小于3 kb的Mutator-like类型MITEs元件,其中长度小于1 000 bp的元件有53个,占69.7%。这些MITEs元件中有42个位于基因间隔区,11个位于基因内含子区,位于5'UTR和3'UTR区的分别有8个和4个,另有1个位于基因编码区。29个MITEs元件带有转座酶以外的功能基因片段,成为pack-MITEs。多个pack-MITEs带有相同的非转座酶基因片段。Mutator-like类型的MITEs对蓖麻基因的表达和基因组的进化有潜在的影响,值得深入分析。

毛竹Stowaway-like MITEs转座子的分离与分析

微型颠倒重复序列(miniature inverted repeat transposable elements,MITEs)是一类对基因组进化和基因表达有重要调节作用的转座子。为分析MITEs在毛竹基因组中的分布特性,借鉴Fast Isolation by AFLP of Sequences Containing repeats(FIASCO)方法,首次构建Stowaway-like MITEs富集文库。随机挑取21个克隆,测序发现2个含有Stowaway-like MITEs序列(Stow-Ph1和Stow-Ph2),阳性率为9.52%。Stow-Ph1和Stow-Ph2的长度分别为260和258bp,具有Stowaway-like MITEs典型的末端颠倒重复序列(terminal inverted repeats,TIRs)和靶位点重复序列(target site duplication,TSD)。Stow-Ph1和Stow-Ph2与水稻的Stow-Os8(FJ266024)的同源性分别为46.4%和52.6%。Stow-Ph1和Stow-Ph2与水稻16类Stowaway-like MITEs的TIRs前20bp的相似性均高于50%,表明毛竹的Stowaway-like MITEs在TIRs上是高度保守的。

Acaricidal activity of Cymbopogon citratus and Azadirachta indica against house dust mites

Objective:To examine the acaricidal effects of the essential oil of Cymbopogon citratits leaf extract(lemongrass)and ethanolic Azadirachta indica leaf extract(neem)against house dust mites Dermatophagoides farinae(D.farinae)and Dermalophagoides pteronyssinus(D.pteronyssinus).Methods:Twenty-five adults mites were placed onto treated filter paper that is soaked with plant extract and been tested at different concentrations(50.00%,25.00%,12.50%,6.25%and 3.13%)and exposure times(24hrs,48hrs,72hrs and 96 hrs).All treatments were replicated 7 times,and the experiment repeated once.The topical and contact activities of the two herbs were investigated.Results:Mortalities from lemongrass extract were higher than neem for both topical and contact activities.At 50%concentration,both 24 hrs topical and contact exposures to lemongrass resulted in more than 91%mortalities for both species of inites.At the same concentration and exposure time,neem resulted in topical mortalities of 40.3%and 15.7%against D.pteronyssinus and D.farinae respectively;contact mortalities were 8.0%and 8.9%against the 2 mites,respectively.There was no difference in topical mortalities of D.pteronyssinus from exposure to concentrations oflemongrass and neem up to 12.50%;lemongrass was more effective than neem at the higher concentrations.Conclusions:Generally,topical mortalities of D.farinae due to lemongrass are higher than that due to neem.Contact mortalities of lemongrass are always higher that neem against both species of mites.

植物中微型反向重复转座元件(MITEs)在作物遗传研究中的应用进展

MITEs(Miniature Inverted-repeat Transposable Elements),是最近发现的几乎在所有生物基因组中广泛分布的一类非自主型DNA转座元件,对基因组的结构和基因表达都有重要的影响。研究发现MTIEs的插入影响了许多重要农艺性状,在作物遗传研究中的应用价值也逐渐显现。为了更好地将这一转座元件利用于作物遗传研究和改良过程,文章概述了MITEs的发现及结构特点,对根据其特点进行预测的分析软件和数据库进行了总结;对MITEs在基因组中的分布特点进行了归纳,发现其在基因组中拷贝数众多,并多在近基因区分布;总结了MITEs同其来源的自主型转座子间的对应关系及转座活性的激活和在基因组中的扩增模式;MITEs对基因表达调控主要通过两种途径:即通过插入改变基因的结构从而影响基因表达和表观遗传水平的调控途径。同时对目前已有的MITEs在作物遗传分析,如开发分子标记,改良性状,构建突变体库等方面进行了总结归纳。

红毛丹基因组中MITEs转座子的鉴定与演化分析

【目的】对红毛丹基因组中的MITEs(miniature inverted-repeat transposable elements)转座子进行鉴定、分类和演化分析,为红毛丹基因组注释、演化及相关基因功能等方面的研究提供理论依据和数据基础。【方法】基于生物信息学方法和红毛丹全基因组数据,对MITEs转座子进行鉴定,并系统分析其在宿主基因组中的分类、含量、家族演化关系、扩增模式、分布模式、插入偏好模式及邻近基因的功能。【结果】红毛丹中共鉴定出MITEs转座子588个,包括PIF/Harbinger、Mutator、Ac-mMITE、hAT和Ginger共5种超家族;插入时间分析发现较大规模的MITEs转座“爆发”事件分别发生于1~2、4~5和17~18百万年前,PIF/Harbinger超家族几乎在于每个时期都占据主导地位,而Ac-mMITE在转座“爆发”事件中参与度最低;插入位置分析发现MITEs在基因侧翼区插入数量最多,分别有136和137个,插入基因内部数为35个,其中2个插入了外显子内;密度分布分析发现该转座子插入虽具有分散性,但整体偏好基因密集区;插入偏好分析发现MITEs在基因两侧呈现为5 kb以内某一位点插入数最高,随着与基因距离接近,插入数越低的偏好分布模式;MITEs邻近基因功能富集分析表明,MITEs插入内部基因主要富集在硫代葡萄糖苷、葡糖异硫氰酸盐和S-糖苷的代谢及生物合成过程,而被插入5’端侧翼区的基因主要富集在生殖和发育相关生物过程,且大多数基因与各种蛋白复合物的结合和某些酶的活性相关。【结论】研究结果有助于理解MITEs转座子在红毛丹基因组中的基本特征和演化模式,丰富了红毛丹基因组的注释信息,填补了红毛丹中MITEs转座子研究的空白并为其性状改良等方面的研究带来了新的视角。

Palynomorphs and Oribatid Mites—From the Denwa Formation, Satpura Basin, Madhya Pradesh, India

Palynological investigation of the Denwa Formation exposed along Denwa river succession at Saptadara picnic point near village Jhirpa, Satpura Basin, Madhya Pradesh, has revealed the presence of spore-pollen, fungal remains and Oribatid mites. Here, the mites are on record for the first time. Presence of fungal remains strongly depicts the prevalence of a very humid climate with high temperature and rainfall in the region. Poor occurrence of spore-pollen restricts the age determination of the studied section;hence, its age assessment is relative. Thus, an over-view of spore-pollen along with dinocysts and insects reported earlier from the subsurface strata comprising Denwa Formation, from other two localities in the nearby area of village Anhoni, is dealt herein, and that had inferred an age—range from Carnian to Rhaetic for the palynoflora and fauna.

Aquatic Phoretic Mites (Acari: Hydrachnidia) Associated with Ectoparasitism of Mosquitoes (Diptera: Culicidae) in the Midwest Region of Brazil

Water mites (Hydrachnidia) are common external parasites of the medically important mosquitoes (Culicidae). Between April 2014 and April 2015, 64 mites from three genus, Arrenurus 71.9%, Limnochares 3.1%, and Hydrachna 25.0%, were collected from female mosquitoes in two rural locations near Cuiabá, Mato Grosso, Brazil. Dipterous species parasitized by water mites belonging to seven species: Anopheles (Nys.) darling, An. evansae, Aedes (Och.) scapularis, Ae. serratus, Mansonia (Man.) wilsoni, Psorophora (Jan.) ferox, Ps. varipes. The most common specimens to accommodate the water mites were Anopheles (Nys.) darlingi and Psorophora (Jan.) varipes. The prevalence of parasitism of mosquitoes by water mites found in this study was less than 5. However, few studies have addressed the ecological role of mites and their biotopes, as well as host-parasite interactions in Brazil.

Aquatic Phoretic Mites (Acari: Hydrachnidia) Associated with Ectoparasitism of Mosquitoes (Diptera: Culicidae) in the Midwest Region of Brazil

Water mites (Hydrachnidia) are common external parasites of the medically important mosquitoes (Culicidae). Between April 2014 and April 2015, 64 mites from three genus, Arrenurus 71.9%, Limnochares 3.1%, and Hydrachna 25.0%, were collected from female mosquitoes in two rural locations near Cuiabá, Mato Grosso, Brazil. Dipterous species parasitized by water mites belonging to seven species: Anopheles (Nys.) darling, An. evansae, Aedes (Och.) scapularis, Ae. serratus, Mansonia (Man.) wilsoni, Psorophora (Jan.) ferox, Ps. varipes. The most common specimens to accommodate the water mites were Anopheles (Nys.) darlingi and Psorophora (Jan.) varipes. The prevalence of parasitism of mosquitoes by water mites found in this study was less than 5. However, few studies have addressed the ecological role of mites and their biotopes, as well as host-parasite interactions in Brazil.

植物MITEs研究进展

微小倒转重复转座因子(miniature inverted-repeat transposable elements;MITEs)是动植物中广泛存在的非自主DNA因子,在基因组结构的进化中扮演重要的角色。文章综述了自MITEs在植物基因组中发现10多年来的研究进展,包括它们的特征、分类与应用,并探讨了植物MITEs研究面临的挑战。

Investigation on Transmission of Epidemic Hemorrhagic Fever Virus between Mice and Mites in the Endemic Areas

Amongthemicecaughtfromtheseparatelitersintheendemicareasofepidemichemorrhagicfever(EHF),WujingCounty,JiangsuProvince,itwasfoundthatApodemusagrariuswasthepredominantspeciesthathasthehighestpositivityrateofepidemichemorrhagicfevervirus(EHFV)antigenandantibodyreaction,whichwaspositivelyrelatedtothenumberofthemiceineachliter.ThelitersinhabitedbyEHFVinfectedmicewereobviouslyaggregate.Ofthegamasidmitesdetectedinthelitersofmice,Eulaelapsstabularisandhemolaelapsglasgowiwerefoundtobethepredominantspecies.TherewasapositiverelationshipbetweenthenumbersofmitesandthepositivityratesofEHFVantigenandantibodyreactionsinthemiceineachlit-ter.ThevirusesisolatedfromApodemusagrariusandmitesfromthesameliterandtheresultsofthemonoclonalantibody-detectionasaywereidentical.

Effect of a commercial air ionizer on dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae(Acari:Pyroglyphidae) in the laboratory

Objective:To investigate the short and long tenn efficacy of a commercial air ionizer in killing Dermatophagoides pteronyssinus(D.pteronyssinus)and Dermalophagoides farinae(D.farinae)mites.Methods:The effect of a commercial ionizer on D.pteronyssinus and D.farinae was evaluated in the laboratory,using a specially designed test.Mortality was assessed after 6,16and 24 hours for direct exposure and after 24,36,48,60 and 72 hours for exposure in simulated mattress.New batches of mites were used for each exposure time.Results:LT_(50)for direct exposure of ionizer was 10 hours for D.pteronyssinus and 18 hours for D.farinae.The LT_(50)for exposure in simulated mattress was 132 hours or 5.5 days for D.pteronyssinus and 72 hours or 3days for D.farinae.LT_(95)for direct exposure of ionizer was 36 hours for D.pteronyssinus and D.farinae.Meanwhile,the LT_(95)for exposure in simulated mattress was 956 hours or 39.8 days for D.pteronyssinus and 403 hours or 16.8 days for D.farinae.Conclusions:This study demonstrates the increasing mite mortalities with increasing exposure time of a commercial ionizer and suggests that negative ions produced by an ionizer kill dust mites and can be used to reduce natural mile populations on exposed surfaces such as floors,clothes,curtains,etc.However,there is reduced efficacy on mites inside stuffed materials as in mattresses and furniture.

Mathematical Model for Two-Spotted Spider Mites System: Verification and Validation

This paper presents and compares four mathematical models with unique spatial effects for a prey-predator system, with Tetranychus urticae as prey and Phytoseiulus persimilis as predator. Tetranychus urticae, also known as two-spotted spider mite, is a harmful plant-feeding pest that causes damage to over 300 species of plants. Its predator, Phytoseiulus persimilis, a mite in the Family Phytoseiidae, effectively controls spider mite populations. In this study, we compared four mathematical models using a numerical simulation. These models include two known models: self-diffusion, and cross-diffusion, and two new models: chemotaxis effect model, and integro diffusion model, all with a Beddington-De Angelis functional response. The modeling results were validated by fitting experimental data. Results demonstrate that interaction scheme plays an important role in the prey-predator system and that the cross-diffusion model fits the real system best. The main contribution of this paper is in the two new models developed, as well as the validation of all the models using experimental data.

Resistance of Commercial Bed Covers against Faecal Pellets of House Dust Mites:Behaviour of Seams and Zippers

This study evaluated the allergen impermeability against airborne allergens of dust mite droppings through all parts of commercial bed covers, including surface seams and zippers. Specimens were taken from places with and without seams and zipper. A novel penetration cell was developed to expose the specimens to an inoculum of purified mite droppings that was assessed for its allergen content Der p1 prior to the penetration tests. Using covers of different construction and material, the penetration level increased significantly in the presence of seams and zippers and could reach up to 6% depending on the seam’s/zipper’s characteristics and quality. Therefore, zippers and seams have to be considered as access points for the penetration of mite droppings. As for the penetration of airborne mite particles through the zipper, the penetration level was greatly attenuated by the presence of a cover strip. Depending on the respective quality and the construction type, the mite allergen Der p1 penetrated most likely through the zipper and seams of the specimens, already after a single laundry cycle. Hence, laundry may compromise the barrier performance and proves to be an important quality feature. In all samples, the textile surface showed sufficient allergen impermeability. Our conclusions provide recommendations to both manufacturers and users.

Study on the Impact of Elements in Water on the Diversity of Water Mites(Acari,Hydrachnidia)Species

In this study the distribution and relationships of element levels in water and water mite species (Acari, Hydrachnidia) selected as model organisms have been examined in two different lakes. Water samples from Eber and Karamik Lakes were analyzed with ICP (ICP-OES Instrument Spectro Genesis Fee, Germany) equipment to determine the element levels in the water. That impact level of these elements on the distribution of species was discussed. Change in the lake water composition was not a significantly determining factor in the number of species and diversities of water mites. However, eutrophication was observed to be a determining factor on the distribution of species.

Rop plays conserved roles in the reproductive and digestive processes of spider mites

Ras opposite(Rop)is known to play an essential role in regulating vesicle trafficking,including synaptic transmission and general secretion.The fundamental roles of Rop have been confirmed by the observation that null mutations in many organisms generate lethal phenotypes during embryogenesis.However,the effects of Rop during the postembryonic stages,especially in non-model organisms,remain largely unknown.Here,we provide new data that enhance our understanding of Rop's roles in the adults of multiple species of Tetranychus spider mites(Acari:Tetranychidae),a class of notorious agricultural pests.Our in silico and experimental evidence demonstrated that Rop is under purifying selection and is highly conserved in Tetranychus spp.RNA interference experiments showed that Rop is required for maintaining normal fecundity but has no significant effect on survival.We further demonstrate that knockdown of Rop darkens the body color of spider mites and blocks the excretion of fecal pellets,which is likely to be related to an abnormality in the excretion of food waste in the digestive system.Overall,our findings clarify novel functions of a vesicle trafficking-related gene in the adult stage of multiple Tetranychus species and highlight the need to evaluate the roles of essential genes in various organisms.

A newly recorded and a new species of torrenticolid mites (Acari:Hydrachnidiae) from China

A new species of Torrenticola(Acari:Hydrachnidia)is reported from China,namely T.(T.)gladiusirostrum Jia,Gu&Guo,sp.nov.And T.(Megapalpis)distans K.O.Viets,1981 is recorded in China for the first time.Both descriptions and illustrations of these species are provided.The new species is characteristic by:dorsal plate arrangement 2+1;infracapitular bay U-shaped,deep and wide,V2 almost at same level of Ap;gnathosoma ventral apodeme short and blunt,rostrum flat and sword-shaped;P-2 and P-3 ventral processes smooth and pointed,and P-2 ventral process curved upwards,P-4 with two ventral extensions.

植物中活性MITEs转座子研究进展

MITEs(Miniature inverted-repeat transposable elements)转座子是一种特殊的转座子,其既有DNA转座子的转座特性——"剪切-粘贴"转座方式,又有RNA转座子的高拷贝特性。目前已被报道的MITEs种类和数量虽然很多,但是关于有转座活性的MITEs的报道却甚少。本文总结了近几年来有关活性MITEs的相关报道,发现具有转座活性的MITEs种类大都分布在Tourist家族,分别是m Ping、m Ging、Ph Tourist1、Tmi1和Ph Tst-3,另外还有Stowaway-like家族的d Tstu1和MITE-39以及Mutator家族的Ah MITE1。文中还分析了这些活性MITEs的结构(TIR和TSD)、拷贝数、进化模式以及转座特性等,为鉴定其他活性MITEs以及MITEs转座和扩增机制的研究奠定了基础。

Distribution of gamasid mites on small mammals in Yunnan Province, China

An investigation of gamasid mites on the body surface of small mammals was carried out in Yunnan Province of China from 1990 to 2004. The small mammal hosts were captured from 25 counties which represent five geographical subregions, namely Middle Subregion of Hengduan Mountains, Southern Subregion of Hengduan Mountains, Eastern Plateau Subregion of Yunnan, Western Plateau Subregion of Yunnan and Southern Moun- tainous Subregion of Yunnan. The captured 10 803 small mammal hosts belong to nine families, 29 genera and 52 species in four orders （Rodentia, Insectivora, Scandentia and Lagomorpha）. A total of 68 571 gamasid mites were collected from the body surface of the captured small mammal hosts and all the gamasid mites were identified to 10 families, 33 genera and 112 species. This paper lists all the mite species, together with their taxonomic position （genera and families） and their corresponding hosts. Much more mite species were found in the Middle Subregion of Hengduan Mountains than in other geographical subregions. The total individuals of mites and small mammals in the Middle Subregion of Hengduan Mountains are also the most plentiful in the five geographical subregions. Three dominant mite species and three dominant small mammal hosts were determined as the dominant species in the investigated areas of Yunnan Province. The dominant hosts are Rattus flavipectus （which accounts for 34.85% of the total individuals）, Apodemus chevrieri （13.43%） and Rattus norvegicus （10.40%） while the dominant gamasid mite species are Laelaps nuttalli （Hirst, 1915） （27.84%）, Laelaps echidninus （Berlese, 1887） （18.38%） and Laelaps guizhouensis （Gu et Wang, 1981） （14.79%）. The results showed the high species diversity of gamasid mites in Yunnan Province and the uneven distribution feature in different subregions.