营养对不同地理种群周氏啮小蜂生物学特性的影响

【目的】研究补充营养对周氏啮小蜂海南本土地理种群和北京地理种群的生物学参数是否有差异。【方法】设置不同的营养(10%蜂蜜、10%蔗糖、10%葡萄糖、水、空白)分别饲喂周氏啮小蜂,统计2个地理种群的寄生率、羽化率、出蜂量、寿命。【结果】2个地理种群的周氏啮小蜂羽化后不久即可进行交配,补充10%蜂蜜、10%蔗糖、10%葡萄糖能显著提高2个地理种群的寄生率、羽化率、出蜂量、雌雄蜂寿命,补充不同的营养对两个地理种群的雌雄比、发育历期的影响差异不显著;饲喂10%蜂蜜的海南地理种群寄生率最高(84.60%),饲喂10%葡萄糖的海南地理种群羽化率最高(97.47%),饲喂10%葡萄糖的海南地理种群出蜂量最高(60.03头),饲喂10%葡萄糖的海南地理种群雌、雄蜂的寿命均为最高,分别为9.13和8.53d。营养和地理种群的交互作用对周氏啮小蜂雄蜂的寄生率、羽化率、出蜂量、雌雄比、雌雄蜂寿命具有显著影响,而对周氏啮小蜂的发育历期无显著影响。【结论】补充营养可不同程度促进周氏啮小蜂生殖力、寿命及寄生率,对寄生蜂繁育和利用其进行生物防治具有一定的意义。     

新入侵害虫椰子织蛾的3种本地寄生蜂

【目的】椰子织蛾是近期入侵中国的棕榈植物重要害虫,研究其天敌寄生蜂,能为椰子织蛾的进一步防控提供科学依据。【方法】在海南岛收集鉴定了椰子织蛾天敌寄生蜂,观察记录寄生蜂发育历期、雌雄性比、成虫寿命等基础生物学特性。【结果】经形态及分子鉴定,收集到的椰子织蛾寄生蜂有幼虫期寄生蜂麦蛾柔茧蜂、蛹期寄生蜂金刚钻大腿小蜂和周氏啮小蜂。在温度(26±2)℃、湿度(75±10)%RH、以椰子织蛾为寄主条件下,麦蛾柔茧蜂、金刚钻大腿小蜂和周氏啮小蜂发育历期分别为11.8、19.6和20.6 d;每头寄主的出蜂量分别为10.1、1.0和81.5头;雌蜂占比分别为26.6%、40.6%和89.8%;每种寄生蜂雌蜂寿命均长于雄蜂。【结论】保护和利用椰子织蛾的3种本地寄生蜂,将有助于椰子织蛾的防控。     

红脉穗螟寄生蜂寄主选择研究

[目的]优化红脉穗螟寄生蜂繁育技术,为该虫的生物防治提供参考。[方法]通过室内饲养研究了红脉穗螟幼虫寄生蜂褐带卷蛾茧蜂和蛹寄生蜂周氏啮小蜂(海南种)对4种昆虫的寄生效果,并对最佳接种比例进行筛选。[结果]褐带卷蛾茧蜂对大蜡螟幼虫寄生效果优于米蛾幼虫,且对黄粉虫和大麦虫幼虫不表现寄生特性,褐带卷蛾茧蜂和大蜡螟幼虫的最佳接种比例为1∶1和2∶1,其中在2∶1接种比例处理中的寄生率和单寄主产蜂量分别为76.67%和34.60头;4种昆虫蛹均可用于繁育周氏啮小蜂,从寄主的繁育成本和寄生效果分析,以黄粉虫蛹效果较最佳,接种蜂虫比以2∶1为宜,此时的单寄主产蜂量为148.60头。[结论]寄主和接种比例不同会影响寄生蜂的寄生效果,本研究中褐带卷蛾茧蜂适宜寄主为大蜡螟,最优蜂虫比为1∶1和2∶1,周氏啮小蜂(海南种)适宜寄主为黄粉虫,最优接种蜂虫比为2∶1。     

啮小蜂寄主接受行为的研究

啮小蜂Tetrastichus sp.是一种群聚性蛹的内寄生蜂,主要寄生于茶长卷叶蛾的蛹.在实验室中,它还能寄生蓖麻蚕、粘虫、亚洲玉米螟、棉褐带卷蛾和家蝇等寄主蛹.在小环境中,啮小蜂雌蜂搜寻大蛹(粘虫)花费的时间要明显少于寻找小蛹(棉褐带卷蛾)所花费的时间.雌蜂多数从寄主的腹部爬上蛹,其次为胸部和头部.88%的雌蜂产卵管插入蛹的位置与上蛹的部位一致.蜂龄(2-6天龄)对雌蜂接受寄主的行为无明显影响.雌蜂对寄主蛹龄有一定的辨别能力,在第7天龄粘虫蛹中产的子蜂数明显减少,对第9天龄的粘虫蛹雌蜂虽作刺探,但未见寄生.随着寄主密度增加,平均每雌寄生的蛹数和产的子蜂数均相应增加,而寄主蛹的寄生率却逐渐下降.随着雌蜂密度增加,寄主蛹的寄生率和平均每头寄生蛹中的子蜂数相应提高,但平均每雌产的子蜂数则逐渐减少.雌蜂在寄生(平均1.74+5.05分.秒)和未寄生(平均2.90±6.50分.秒)寄主中产卵管插入的时间无明显差异,但在寄生(平均每蛹为182.20±85.06头)和未寄生(平均为87.80±69.50头)寄主中产的子蜂数则有明显差异(P<0.02).表明啮小蜂雌蜂对已寄生寄主蛹无明显的辩别能力.     

亚洲玉米螟蛹提取物对啮小蜂寄生行为的影响

在实验室条件下,啮小蜂Tetrastichus sp.能寄生亚洲玉米螟Ostrini of urnacalisGuenee和棉褐带卷蛾Adoxophyes orana Fischer Von Rosleeslanrm两种昆虫的蛹.但是,前者的寄生率明显高于后者.两种寄主蛹的三氯甲烷提取物均能诱导啮小蜂雌蜂加强搜索,滞留和敲打等行为.但亚洲玉米螟蛹提取物尚能诱导雌蜂刺探行为,棉褐带卷蛾提取物则没有这种行为反应.提供寄主前,啮小蜂先经受玉米螟蛹提取物刺激4小时,即可提高其对棉褐带卷蛾的寄生率.在产卵活动期间,持续存在提取物的刺激可以增强啮小蜂雌蜂的学习反应.     

温度对蝇蛹俑小蜂寄生瓜实蝇蛹功能反应的影响

【目的】蝇蛹俑小蜂是很多双翅目害虫的蛹寄生蜂。了解温度对寄生蜂寄生效能的影响是利用寄生蜂控制害虫的重要前提。【方法】实验室条件下设置温度为21、24、27、30、33℃,测定温度对蝇蛹俑小蜂雌蜂寄生瓜实蝇蛹功能反应的影响。蝇蛹俑小蜂对瓜实蝇蛹的功能反应用Michaelis-Menten-Ⅱ型功能反应模型N_a=AN/(F+N)进行拟合。【结果】不同温度下蝇蛹俑小蜂的寄生潜能(A)和寄主半饱和密度(F)不同。当温度在27℃时,其寄生潜能最大;而寄主半饱和密度随着温度升高而降低。【结论】瓜实蝇在瓜地盛发期的栖境温度适宜蝇蛹俑小蜂的寄生。     

椰子织蛾不育技术的生物学基础

【背景】椰子织蛾是新入侵我国海南岛的棕榈害虫,昆虫不育技术是控制该害虫的潜在措施。【方法】通过研究椰子织蛾生殖、发育、存活等特性,探讨椰子织蛾不育技术的生物学基础。【结果】在(28±2)℃、(70±10)%RH、以椰子老叶饲养的条件下,每雌产卵量约170粒,净增值率约55.4,倍增时间约9.6 d,表明椰子织蛾可在室内大量饲养,为辐射不育提供虫源。椰子织蛾雌雄比为1∶1.04,雄虫先熟,产卵前期短,产卵期集中,表明该害虫交配行为相对简单,有利于不育雄虫发挥效能。雌蛹显著重于雄蛹,有利于不育过程中雌雄虫的分离。发育起点温度11.5℃,有效积温996.9日度,在海南岛每年发生4~5代,这些数据可用来预测椰子织蛾种群动态,便于释放不育雄虫。【结论与意义】本研究从生物学角度表明椰子织蛾可用昆虫不育技术进行防控,为其进一步的不育技术研发提供相关信息。     

啮小蜂雌蜂接受寄主线索的探讨

啮小蜂Tetrastichussp.是一种群聚性的蛹内寄生蜂,主要寄生茶长卷叶蛾Homona magnanima的蛹,实验室中亦能寄生亚洲玉米螟Ostrinia furnacalis的蛹。研究了速冻寄主蛹、视觉和嗅觉线索在啮小蜂寄主接受中的作用,实验结果表明,速冻寄主蛹对啮小蜂接受寄主的影响不大,啮小蜂雌蜂主要是通过嗅觉线索接受寄主的,而视觉在寄主接受过程中仅起辅助作用。     

椰心叶甲啮小蜂的繁殖生物学研究

对椰心叶甲啮小蜂羽化、求偶、交配、产卵、繁殖现象进行了观察研究。结果表明,补充营养对雌蜂的寿命和繁殖力均有影响。没有补充营养的情况下,雌蜂的平均寿命为2.48 d,一生可产21.43粒卵;每天补充10%蜜糖水,且雌蜂与寄主(椰心叶甲初蛹)比例为1:3时,雌蜂平均寿命为13.43 d,一生可产53.6粒卵;每天补充10%蜜糖水,且雌蜂与寄主(椰心叶甲初蛹)比例为1:1时,雌蜂平均寿命为14.78 d,一生可产42.5粒卵。椰心叶甲啮小蜂对水椰八角铁甲蛹的寄生率为82.25%,平均每寄主出蜂量为12.24头。     

周氏啮小蜂非典型气味受体基因的cDNA序列及进化分析

【目的】对重大林业害虫美国白蛾Hyphantria cunea(Drury)的重要寄生性天敌周氏啮小蜂Chouioia cunea Yang(膜翅目:姬小蜂科)一个Or83b直同源基因的cDNA全长序列CcOr1进行多角度的进化分析,为研究周氏啮小蜂嗅觉分子机制奠定基础。【方法】通过转录组测序的方法鉴定CcOr1基因全长,并对该基因进行序列及进化分析。【结果】该基因长度为1 428 bp,编码475个氨基酸;蛋白二级结构预测具脊椎动物G蛋白典型的七跨膜结构域。【结论】该基因较为保守,主要接受负选择压力。作为寄主广泛的寄生蜂,周氏啮小蜂与寄主单一的类群相比,其同义突变率较低,密码子偏好性较高。     

The phylogenetic placement of Ostropales within Lecanoromycetes (Ascomycota) revisited

Results of molecular studies regarding the phylogenetic placement of the order Ostropales and related taxa within Lecanoromycetes were thus far inconclusive. Some analyses placed the order as sister to the rest of Lecanoromycetes, while others inferred a position nested within Lecanoromycetes. We assembled a data set of 101 species including sequences from nuLSU rDNA, mtSSU rDNA, and the nuclear protein-coding RPB1 for each species to examine the cause of incongruencies in previously published phylogenies. MP, minimum evolution, and Bayesian analyses were performed using the combined three-region data set and the single-gene data sets. The position of Ostropales nested in Lecanoromycetes is confirmed in all single-gene and concatenated analyses, and a placement as sister to the rest of Lecanoromycetes is significantly rejected using two independent methods of alternative topology testing. Acarosporales and related taxa (Acarosporaceae group) are basal in Lecanoromycetes. However, if the these basal taxa are excluded from the analyses, Ostropales appear to be sister to the rest of Lecanoromycetes, suggesting different ingroup rooting as the cause for deviating topologies in previously published phylogenies.     

Genome Analysis inNeurospora crassa;Cloning of Four Lociarginine-1(arg-1),methionine-6(met-6),unknown-7(un-7), andribosome production-1(rip-1) and Associated Chromosome Walking

We have cloned fourNeurospora crassagenes by complementation analysis. Cloned genes include thearginine-1(arg-1),methionine-6(met-6),unknown-7(un-7), andribosome production-1(rip-1) loci. Chromosome walks were initiated in ordered cosmid libraries from the cloned loci. A total of about 700 kb of theNeurosporagenome is covered in these walks.     

Prosthecium species with Stegonsporium anamorphs on Acer

Data from microscopic morphology, single-spore cultures, and DNA analyses of teleomorphs and anamorphs support the recognition of five species of Prosthecium with Stegonsporium anamorphs on Acer: P. acerinum sp. nov., the teleomorph of S. acerinum; P. acerophilum comb. nov., formerly known as Dictyoporthe acerophila; P. galeatum comb. nov., originally described as Massaria galeata; P. opalus sp. nov.; and P. pyriforme sp. nov., the teleomorph of S. pyriforme s. str. The morphology of both type specimens and freshly collected material was investigated. The teleomorphs have brown ellipsoidal ascospores with five distosepta and often a longitudinal distoseptum. The anamorphs of all species described here belong to Stegonsporium; their connection to the Prosthecium teleomorphs was demonstrated by morphology and DNA sequences of single spore cultures derived from both ascospores and conidia. The anamorphs and teleomorphs of all five Prosthecium species are described and illustrated by LM images, and a key to these species is provided. As perceived from this work, S. pyriforme is restricted to Europe and does not occur in North America, whereas S. acerinum is restricted to North America, not found in Europe. The host associations given in the literature are revised and evidence is provided that only A. opalus, A. pseudoplatanus, and A. saccharum are confirmed hosts of Prosthecium with Stegonsporium anamorphs. Molecular phylogenetic analyses of tef1, ITS rDNA, and partial nuLSU rDNA sequences confirm that the species with Stegonsporium anamorphs are closely related to P. ellipsosporum, the generic type species. Stilbospora macrosperma is confirmed as the anamorph of P. ellipsosporum by DNA data of single spore isolates obtained from both ascospores and conidia.     

Evolutionary relationships among aquatic anamorphs and teleomorphs: Lemonniera, Margaritispora, and Goniopila

The hypothesis that similar conidial morphologies in aquatic hyphomycetes are a result of convergent evolution was tested using molecular sequence data. Cladistic analyses were performed on partial sequences of 28S rDNA of seven species of Lemonniera, one species of Margaritispora and one species of Goniopila. Lemonniera has tetraradiate conidia with long arms, whereas Margaritispora and Goniopila have typically globose (isodiametric) conidia, with short conical protuberances in a stellate or quadrangular arrangement. Lemonniera and Margaritispora have phialidic conidiogenesis and both produce dark, minute sclerotia in culture whereas Goniopila has holoblastic conidiogenesis and does not produce sclerotia in culture. Goniopila produces a microconidial phialidic synanamorph in culture. All three genera have schizolytic conidial secession. Molecular analyses demonstrate that Lemonniera species are placed in two distinct clades: one within Leotiomycetes; the other within Pleosporales, Dothideomycetes. Margaritispora is placed with Lemonniera species within Leotiomycetes. Goniopila and Lemonniera pseudofloscula are placed within Dothideomycetes. No morphological character was entirely congruent with the molecular derived phylogeny. This suggests that for the group of species studied, conidial shape is not a reliable indicator of phylogeny but more likely the result of convergent evolution in response to the aquatic environment.     

Characterisation of cell wall polysaccharides, arabinogalactans-proteins (AGPs) and phenolics of Cola nitida, Cola acuminata and Garcinia kola seeds

Many Cola plant species are endemic to West and Central Africa. Cola acuminata and Cola nitida are used as masticatory when fresh, while the dried nuts are used for beverages and pharmaceutical purposes in Europe and North America. Garcinia kola seeds, that serve as a substitute for the true kola nuts, are used in African traditional medicine for the treatment of various diseases, including colic, headache and liver cirrhosis. Seeds extracts of G. kola are also known for their anti-inflammatory, antimicrobial and antiviral properties. To gain information on the chemical properties of the kolas, we have isolated and analyzed cell wall polysaccharides, arabinogalactan-proteins and phenolic substances from the seeds of the three kola species. The sugar composition of cell wall material of C. acuminata, C. nitida and G. kola revealed that Gal (up to 30%), Ara, GalA and Glc as the predominant monosaccharides, representing approximately 90% by mol of the total hydrolysable sugar present in this material. In Ammonium oxalate cell wall fraction, GalA was found to be the major sugar present in all kola species. In the alkali-soluble fraction, there were significant differences in the level of Glc and Gal. The level of Glc was high in C. acuminata and C. nitida while the level of Gal and Xyl were high in C. nitida and G. cola. Isolation and quantification of arabinogalactan-proteins demonstrate that G. kola seeds contained four to eight times more of these proteoglycans than the seeds of the other two species. Finally, analysis of soluble phenolic substances shows that caffeine and catechin were largely represented in C. acumina and C. nitida seeds, with caffeine accounting for 50% of all soluble phenolics. These findings indicate that the three Kola seeds are highly enriched in pectins and proteoglycans and that C. acuminata and C. nitida can be used as a possible source of caffeine and catechin.     

New species of Phaeoramularia, Pseudocercospora and Stenella from Western Ghats of India

Four new species of the hyphomycete genera Phaeoramularia viz. Ph. caesalpinae, Pseudocercospora viz., Ps. tiliacearum, Stenella, viz. S. argyreiae and S. grewiae occurring on Caesalpinia bonducella Fleming (Caesalpiniaceae), Grewia sp. (Tiliaceae), Argyrea sp. Lour (Convolvulaceae) and Grewia sp. L. (Tiliaceae), respectively are described and illustrated here. All these fungi were collected from Western Ghats of India.     

甘菊ClHSP70与ClHSP90基因的克隆及表达分析

该研究以甘菊(Chrysanthemum lavandulifolium)为实验材料,通过RT-PCR方法从甘菊转录组数据中分离出热激蛋白合成相关基因,命名为ClHSP70和ClHSP90。序列分析表明,ClHSP70基因ORF全长为2 559bp,编码852个氨基酸,蛋白功能区预测表明含有典型的HSP70蛋白NBD和SBD保守结构域;ClHSP90基因ORF全长为2 094bp,编码697个氨基酸,含有HATPase结构域和HSP90保守结构域。生物信息学分析表明,甘菊ClHSP70与大豆(Glycine max)和烟草(Nicotiana tomentosiformis)HSP70蛋白有较高的一致性,ClHSP90基因编码的氨基酸序列与紫茎泽兰(Ageratina adenophora)HSP90高度相似;实时荧光定量表达分析表明,在42℃处理不同时间,甘菊叶片中ClHSP70和ClHSP90基因表达均在0.5h时显著增加,1h达到最大值,2h后缓慢下降;不同组织表达分析表明,甘菊在42℃处理1h后,ClHSP70在成熟叶中的表达量显著高于嫩叶和根等其他组织;ClHSP90在成熟茎中的表达量最高。研究说明,ClHSP70和ClHSP90基因具有热激蛋白特征,参与了甘菊热胁迫应答过程,该研究结果为以后深入研究其基因功能奠定了基础。     

Molecular and morphological characterization of Leveillula (Ascomycota: Erysiphales) on monocotyledonous plants

Leveillula on monocotyledonous plants have been recorded as L. taurica by several authors, whereas the fungus on Allium has been described as an independent species, namely L. allii, by some authors. We sequenced ca 600 bp of the rDNA ITS region for two Leveillula specimens from Allium and Polianthes (both from monocotyledons) and compared them with several already published sequences from Leveillula isolates from dicotyledons. Pair-wise percentages of sequence divergences were calculated for all Leveillula isolates. The ITS sequence of the Polianthes isolate was identical to L. taurica on Helianthus and Vicia. The sequence of the Allium isolate was 99.5 % identical to L. taurica on Euphorbia, Haplophylum, Peganum, etc. These results suggest close relationships between monocot and dicot pathogenic Leveillula species. The identity between two monocot isolates was 98.4 %. Phylogenetic analysis revealed that the two monocot isolates do not group into a clade together. This result suggests that Leveillula acquired parasitism to monocots at least twice independently.     

A polysaccharide from Lichina pygmaea and L. confinis supports the recognition of Lichinomycetes

The lichen-forming order Lichinales, generally characterized by prototunicate asci and the development of thalli with cyanobacteria, has recently been recognized as a separate class of ascomycetes, Lichinomycetes, as a result of molecular phylogenetic studies. As alkali and water-soluble (F1SS) polysaccharides reflect phylogeny in other ascomycetes, a polysaccharide from Lichina pygmaea and L. confinis was purified and characterized to investigate whether these F1SS compounds in the Lichinomycetes were distinctive. Nuclear magnetic resonance (NMR) spectroscopy and chemical analyses revealed this as a galactomannan comprising a repeating unit consisting of an α-(1→6)-mannan backbone, mainly substituted by single α-galactofuranose residues at the O-2- or the O-2,4- positions linked to a small mannan core. With the exception of the trisubstituted mannopyranose residues previously described in polysaccharides from other lichens belonging to orders now placed in Lecanoromycetes, the structure of this galactomannan most closely resembles those found in several members of the Onygenales in Eurotiomycetes. Our polysaccharide data support molecular studies showing that Lichina species are remote from Lecanoromycetes as the galactofuranose residues are in the α-configuration. That the Lichinomycetes were part of an ancestral lichenized group can not be established from the present data because the extracted polysaccharide does not have the galactofuranose residue in the β configuration; however, the data does suggest that an ancestor of the Lichinomycetes contained a mannan and was part of an early radiation in the ascomycetes.