广西地区罗非鱼外寄生车轮虫的形态分类学及多样性研究

采用活体观察、吉姆萨与干银法染色等技术,运用国际间统一特定方法及齿体定位描述法对采自广西地区的罗非鱼(单性鱼吉富、奥尼系列)的外寄生车轮虫进行详细的形态分类学与多样性研究,研究结果共计获得车轮虫属2种,拟车轮虫属与三分虫属各1种,分别为:刺纹车轮虫Trichodina centrostrigata Basson et al.,1983、异齿车轮虫Trichodina heterodentata Duncan,1977、非洲拟车轮虫Paratrichodina africana Kazubski&El-Tantawy,1986与直齿三分虫Tripartiella orthodens Basson&Van As,1987。其中,非洲拟车轮虫为中国新纪录,刺纹车轮虫和直齿三分虫为中国广西地区新纪录。非洲拟车轮虫表现出寄主和寄生部位的专一性;进一步应用SPSS统计软件对非洲拟车轮虫进行了种群差异性分析。     

瓦氏黄颡鱼2种寄生车轮虫形态分类

采用国际上使用的"统一特定描述"和"齿体定位描述"方法对寄生在瓦氏黄颡鱼(Peleteobagrusvachelli)鳃上的适度车轮虫(Trichodina modesta)和马氏车轮虫(T.mastu)2种车轮虫的虫体外形、附着盘、齿体、辐线、中央颗粒、核器、口围绕体等形态特征进行了较为详细的描述,并分别与已报道的其他适度车轮虫、马氏车轮虫种群及相似种的形态特征进行了比较。实验证实了瓦氏黄颡鱼为适度车轮虫的寄主新纪录。     

南中国海野生海水鱼类外寄生车轮虫新记录（英文）

研究对采自南中国海的7种海水鱼类进行了调查研究,并分离获得4种隶属于车轮虫属的种类,分别为浦氏车轮虫Trichodina puytoraci Lom,1962;日本车轮虫Trichodina japonica Imai,et al.,1991;直钩车轮虫Trichodina rectuncinata Raabe,1958与鲀车轮虫Trichodina fugu Imai,et al.,1997。研究发现鲀车轮虫Trichodina fugu Imai,et al.,1997为寄主鱼虫纹东方鲀Takifugu vermicularis的病原,且能在野生条件下将其致死。上述4种车轮虫的形态分类学数据均基于干银法标本获得。研究是对我国南中国海车轮虫的首次报道。     

南中国海野生海水鱼类外寄生车轮虫新记录

研究对采自南中国海的7种海水鱼类进行了调查研究, 并分离获得4种隶属于车轮虫属的种类,分别为浦氏车轮虫Trichodina puytoraci Lom, 1962; 日本车轮虫Trichodina japonica Imai, et al., 1991; 直钩车轮虫Trichodina rectuncinata Raabe, 1958 与鲀车轮虫Trichodina fugu Imai, et al., 1997。研究发现鲀车轮虫Trichodina fugu Imai, et al., 1997为寄主鱼虫纹东方鲀Takifugu vermicularis的病原, 且能在野生条件下将其致死。上述4种车轮虫的形态分类学数据均基于干银法标本获得。研究是对我国南中国海车轮虫的首次报道。       

重庆地区鲫外寄生车轮虫形态分类学研究及一新种的描述(英文)

在对重庆地区进行鱼类寄生虫学的调查过程中,从鲫鳃表获得3种隶属于车轮虫属Trichodina Ehrenberg,1830的外寄生车轮虫,其中含一新种,短棘车轮虫Trichodina brevicirra sp.nov,其典型的鉴别性特征为其短细的齿棘。另外两种车轮虫分别为沃玛车轮虫Trichodina ngoma Van As&Basson,1992与网状车轮虫Trichodina reticulata Hirschman&Partsch,1955;沃玛车轮虫为亚洲新记录种。文章对网状车轮虫的3种群进行了详尽的比较讨论研究,尽管该三种群间存在着细微的种群内差异,但网状车轮虫的典型特征则显而易见地存在于三种群间,即为附着盘中央具有8-16个球状或卵圆形的中央颗粒。       

车轮虫齿体特征的量化及其种内种间系统发育的研究

齿体特征是车轮虫物种鉴定的一个重要依据。本文首次提出一种齿体结构面积比例量化法,即通过对齿钩、齿锥、齿棘、齿体环各部分反口面观面积的测量,分别计算出前三者与所在齿体的面积比以及所有齿体总面积与齿体环的面积比,从而将齿体特征转换为量化指标依据所测量化值,采用相似性聚类法,我们首先探讨了显著车轮虫(Trichodina nobbillis chen,1963)的三个种群的亲缘关系,然后以劳牧小车轮虫(Trichodinella lomi Xu,Song ＆ Warren,1999)为外类群,选择显著车轮虫(Trichodina nobillis chen,1963)、异齿车轮虫(Trichodina heterodentata Duncan,1977)、杜氏车轮虫(Trichodina dormergui Wallengren,1897)和Trchodina fahaka(Khaled A．S．Al-Rasheid,2000)为研究对象,对车轮虫种间亲缘关系进行了分析。结果表明,Pdr值可以有效地表现种群间的差异;同时还发现齿棘面积比例较高的杜氏车轮虫和异齿车轮虫进化较晚,而齿棘面积比例较低的显著车轮虫进化较早,并得出了齿棘越发达,车轮虫越进化这一结论,支持了徐奎栋等所提出的游走亚目六种基本齿型的进化顺序。这种量化研究方法不但可对车轮虫齿体的各部分结构以及它们之间的相互关系进行定量描述,而且还可以这些数据为基础对车轮虫种群间及物种间亲缘关系进行研究。     

矩形车轮虫的再描述

目的:我们对泸州市鲇类寄生车轮虫进行调查,对于已经发现,但由于原来的技术水限制需要重新描述的,或缺少资料的车轮虫,给予重新描述或补充新的资料。方法:用国际间统一的干银法染色以显示车轮虫的附着盘结构和口围绕度,用Lom(1958)倡导的"统一的特定方法"(Uniform specifi characteristic system)进行测量,用Van&Bassion(1989)提供的方法描述车轮虫的齿体。结果:对寄生在泸州地区养殖鱼类斑点叉尾鮰(Ietalurus punetaus)的鳃上的车轮虫进行了描述,该车轮虫是矩形车轮虫(Trichodina rectangli)。结论:矩形车轮虫是陈启鎏和谢杏人1964年在青鱼、草鱼等鱼身体上发现的,但是没有显微照片。国际上有许多它的同种异名的车轮虫的描述,这些文献也只有附着盘的显微照片。斑点叉尾鮰是矩形车轮虫的新寄主记录。本研究用国际统一的方法对矩形车轮虫进行描述,并绘出了矩形车轮虫的齿体定位图,提供了完整的统计数据,以及完整的显微照片,即附着盘、口围绕度和细胞核显微照片。     

基于18S rDNA与ITS-5.8S rDNA对 重庆地区网状车轮虫的种内分化研究

本研究基于形态和分子数据对采自重庆地区5个地理株系的网状车轮虫(Trichodina reticulata)进行了比较研究及重描述。研究结果表明,网状车轮虫不同株系表现出不同的表型分化,含形态略有不同的齿体及有或无中央颗粒,因而具有明显的种内形态多样性。不同地理株系网状车轮虫的18S rDNA序列相似度在99.0%~100%之间,遗传距离为0.000~0.008,并在三大变异区(V4、V5与V7)均具一致的二级结构,表明不同株系的18Sr DNA相似度与遗传距离均属种内水平。综合18SrDNA和ITS-5.8S rDNA的变异位点和系统发育对种内分歧的研究分析显示,来自不同地理分布和宿主的网状车轮虫株系皆因相同的变异位点而聚为一枝,以此推断网状车轮虫的种内分化主要受其基因的影响,地理分布与宿主差异等环境影响在目前的种群分化阶段暂未突显。此外,本研究进一步验证了中央颗粒不能作为网状车轮虫的主要鉴别性特征的观点。     

重庆地区泥鳅体外寄生车轮虫的形态分类学研究

在重庆地区鱼类寄生虫的调查过程中,从淡水鱼泥鳅的鳃上获得四种外寄生车轮虫,经鉴定隶属车轮虫科（Trichodinidae）、车轮虫属（Trichodina）,含1车轮虫未定种Trichodina．sp．和3已知种,即：适度车轮虫（TrichodinamodestaLom,1970）,斜齿车轮虫（Trichodina lechriodentata Zhao＆Tang,2007）及拟黑色车轮虫（TrichodinaparanigraTangetal,2005）。车轮虫的形态学特征统计采用Lom（1958）倡导的统一特定方法,齿体的定位描述则采用Van As＆Basson（1989）和Tang,Zhao＆Chen（2005）改进的方法进行     

寄生于重庆地区鲢、鳙及草鱼五种外寄生车轮虫的描述

对采自重庆地区寄生于鲢、鳙及草鱼鳃上的5种外寄生车轮虫进行了形态学及分类学研究,其分别隶属于：车轮虫属、小车轮虫属及三分虫属,其中包含1新种和中国2新纪录。即钝圆车轮虫Trichodina obtusiformis sp．nov．,急尖车轮虫T．acuta Lom,1961,显著车轮虫T．nobilis Chen,1963,周丛小车轮虫Trichodinella epizootica（Rabbe,1950）Sramek-Husek,1953和大型三分虫Tripartiella macrosoma Basson ＆ Van As,1987。文中对新种进行了详细的描述并提供了新种及已知种的附着盘银染标本之显微照片及齿体线条图。     

重庆地区鲫鱼外寄生车轮虫的记述及一新种描述

报道了寄生于重庆地区淡水养殖鲫鱼鳃上的车轮虫属2种,小车轮虫属1种,其中1新种和中国2新纪录种.文中对新种作了详细的描述并提供了新种(包括成体与幼体分裂期)及新纪录种附着盘的银染标本照片及齿体的线条图.     

Morphological and molecular characterization of two Trichodina (Ciliophora,Peritrichia) species from freshwater fishes in China

In the present study, we provide morphological and molecular characterization of two Trichodina species, T. acuta Lom, 1970 and T. funduli Wellborn, 1967, isolated from koi (Cyprinus carpio) and loach (Paramisgurnus dabryanus), respectively. Morphological characters of the two Trichodina species were mainly investigated on the basis of dry silver nitrate-impregnated specimens. Both species are medium-sized and possess well-developed denticles comprising strongly sickle-shaped blades, well-developed central parts, and straight rays. Trichodina acuta can be easily distinguished from the other Trichodina species that possess a clear central circle by the well-developed sharp blade apophysis, and the gap between ray tip and central circle. Trichodina funduli is a poorly known species that is easily confused with T. heterodentata Duncan, 1977, however the latter species has thinner denticles. The small subunit ribosomal RNA gene sequences of Trichodina acuta and T. funduli were incorporated into phylogenetic analyses. Our findings suggest that the phylogenetic lineage of trichodinids might not correspond with their living environments, host species or even some morphological characteristics.     

Host specificity of trichodinid ectoparasites of freshwater fish

Ciliophorons of the family Trichodinidoe comprise seven genera, all of which are commensolists or parasites - mainly on aquatic hosts such as other ciliophorans, coelenterates, planctonic crustaceans, molluscs, echinoderms, amphibians and fish. Although the first species of this family, Trichodina pediculus, was described from material collected from Hydra, most literature concerns the trichodinids of fish-particularly cultured freshwater fish. These ciliophorans have been implicated in severe disease and mortalities of fish, causing severe economic losses in various parts o f the world. In spite o f the confused taxonomy o f the Trichodinidae, it now appears that they fall into four distinct groups representing a line of specialization towards a more exclusive niche on the host fish. The more opportunistic species, with a broad host range, tend to be larger skin parasites, while the more specialized are smaller and usually only parasitize the gills o f their specific host.     

Non-lethal detection of DNA from Cichlidogyrus spp. (Monogenea, Ancyrocephalinae) in gill mucus of the Nile tilapia Oreochromis niloticus

Infection of Nile tilapia Oreochromis niloticus by monogeneans of the genus Cichlidogyrus is harmful. Currently, diagnosis of this infection is based on invasive techniques and the identification of isolated parasites by their morphology. To facilitate diagnosis, we have developed a non-lethal polymerase chain reaction (PCR) test for detection of Cichlidogyrus spp. DNA in the gill mucus of O. niloticus, using 5 pairs of specific primers based on Cichlidogyrus sclerosus 28S rRNA (Cicly 1 to Cicly 5) which generate fragments of approximately 188, 180, 150, 159 and 189 bp, respectively. PCR specificity was tested using genomic DNA extracted individually from 175 isolated Cichlidogyrus spp., 75 Gyrodactylus cichlidarum and 75 endopararasitic Enterogyrus spp., as well as from 75 protozoans Trichodina spp. The Cicly primers were used to detect Cichlidogyrus spp. DNA in mucus from the gills of 23 Nile tilapia confirmed to be infected with the parasite. Negative controls consisted of 45 uninfected Nile tilapia. The limit of sensitivity of the assay was 1.2 ng of purified parasite DNA. The Cicly primers did not amplify DNA from the mucus of non-infected Nile tilapia, G. cichlidarum, Trichodina spp. or Enterogyrus spp. In all cases, the sensitivity and specificity of the test were 100%. The sequences of all the amplified fragments showed a high similarity to that of the 28S rRNA region of C. sclerosus (93 to 100% identical to GenBank Accession No. DQ157660.1). We provide evidence for a safe and non-invasive DNA-based diagnostic method for the presence of Cichlidogyrus in the gill mucus of O. niloticus.     

Host specificity in parasitic mistletoes (Loranthaceae) in New Zealand

1. We quantify the degree of host specificity for the five extant New Zealand loranthaceous mistletoes ( Alepis flavida, Ileostylus micranthus, Peraxilla colensoi, Peraxilla tetrapetala and Tupeia antarctica ).
2. Host specificity is highest for A. flavida, P. colensoi and P. tetrapetala which primarily parasitize species of Nothofagus , and lowest for T. antarctica and especially I. micranthus which parasitize a wide range of host species.
3. These patterns of host specificity support the suggestion that relative host abundance is a key factor determining the degree of host specialization in mistletoes (resource fragmentation hypothesis). While evolutionary history may be important in the specificity of the mistletoe–host relationship in some situations, our data suggest that for New Zealand mistletoes evolutionary history simply reflects the temporal component of relative host abundance.
4. We conclude that it is the stability of host availability through time and space which is the dominant factor determining host specificity patterns.     

Choosing suitable hosts: common cuckoos Cuculus canorus parasitize great reed warblers Acrocephalus arundinaceus of high quality

We investigated the hypothesis that the common cuckoo Cuculus canorus selects host pairs of good phenotypic quality. As there is some evidence that cuckoos may select hosts within a population non-randomly based on external cues reflecting their foster abilities, we predicted that great reed warbler Acrocephalus arundinaceus pairs parasitized by the cuckoo would exhibit higher quality than unparasitized ones. To test this assumption, we evaluated two different parameters indicating host quality: body condition and characteristics of host eggs. We found that parasitized females showed significantly better body condition than unparasitized ones, and the model showed that the probability of being parasitized by the cuckoos increased with increasing body condition. Moreover, the likelihood of being parasitized by a cuckoo within the great reed warbler population increased with decreasing colour variability within clutches: parasitized females allocated costly blue pigments to eggshells more equally compared with unparasitized ones. Our study revealed that cuckoos parasitize great reed warbler females of higher quality, as reflected in host body condition and egg colour characteristics. In highly mimetic systems, cuckoos may choose to parasitize hosts with eggs displaying low intraclutch variation, both because this leads to reduced rejection and because these hosts are of high quality.     

The Evolution of Body Size,Antennal Size and Host Use in Parasitoid Wasps (Hymenoptera: Chalcidoidea): A Phylogenetic Comparative Analysis

Chalcidoid wasps represent one of the most speciose superfamilies of animals known, with ca. 23,000 species described of which many are parasitoids. They are extremely diverse in body size, morphology and, among the parasitoids, insect hosts. Parasitic chalcidoids utilise a range of behavioural adaptations to facilitate exploitation of their diverse insect hosts, but how host use might influence the evolution of body size and morphology is not known in this group. We used a phylogenetic comparative analysis of 126 chalcidoid species to examine whether body size and antennal size showed evolutionary correlations with aspects of host use, including host breadth (specificity), host identity (orders of insects parasitized) and number of plant associates. Both morphological features and identity of exploited host orders show strong phylogenetic signal, but host breadth does not. Larger body size in these wasps was weakly associated with few plant genera, and with more specialised host use, and chalcidoid wasps that parasitize coleopteran hosts tend to be larger. Intriguingly, chalcidoid wasps that parasitize hemipteran hosts are both smaller in size in the case of those parasitizing the suborder Sternorrhyncha and have relatively larger antennae, particularly in those that parasitize other hemipteran suborders. These results suggest there are adaptations in chalcidoid wasps that are specifically associated with host detection and exploitation.