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1.
Turbot (11–70 cm long) and brill (21–70 cm long) were collected in the summer of 1968 north of the Brown Bank, Texel Hole and were infected by Bothriocephalus scorpii. Infections occurred even in the first year of life of the fish. In turbot, with increasing length, the average weight of tapeworm rose from 0–6 to 14-9 g/flsh. Brill were less commonly infected and then only slightly. The intermediate host of the tapeworm seems to be Gobius species, upon which juvenile turbot and brill prey most.  相似文献   

2.
Extracts of the tapeworm, Hymenolepis diminuta, catalyse N5,10-methylene-tetrahydrofolate-dependent release of tritium from [5-3H]dUMP, indicating the presence of thymidylate synthase. The enzyme activity was found in immature, mature and gravid proglottids, as well as in immature and mature oncospheres. The reaction showed pH optimum at 7.5. Its Michaelis constants were approximately 2 and 15 microM for dUMP and (+/-), L-N5,10-methylenetetrahydrofolate, respectively. Incubation of the tapeworm extracts with 5-F-[3H]dUMP and N5,10-methylenetetrahydrofolate resulted in formation of a labelled complex, separable under conditions of SDS polyacrylamide electrophoresis (mol. wt. of approx. 34,000), corresponding to thymidylate synthase subunit. Results of gel filtration of the above complex, under nondenaturing conditions, pointed to a dimeric structure of the enzyme.  相似文献   

3.
We examined the role that predation of infected conspecific fish and postcyclic transmission might play in the life cycle of the Asian fish tapeworm, Bothriocephalus acheilognathi (Cestoda: Pseudophyllidea) Yamaguti, 1934. Young-of-the-year (YOY) bonytail chub (Gila elegans) were exposed to copepods infected with B. acheilognathi and subsequently fed to subadult bonytail chub. Within 1 wk after consumption of the YOY chub, subadults were necropsied and found infected with gravid and nongravid tapeworms. This study provides evidence that postcyclic transfer of B. acheilognathi can occur. Postcyclic transmission may be an important life history trait of B. acheilognathi that merits consideration when studying the impact and distribution of this invasive and potentially pathogenic tapeworm.  相似文献   

4.
The great white shark Carcharodon carcharias Linnaeus, 1758 is a versatile and fierce predator (and responsible for many shark attacks on humans). This apex predator feeds on a wide range of organisms including teleosts, other elasmobranchs, cephalopods, pinnipeds, and cetaceans. Although much is known about its diet, no trophic links have been empirically identified as being involved in the transmission of its tapeworm parasites. Recently, the use of molecular tools combined with phylogenetics has proven useful to identify larval and immature stages of marine tapeworms; utilization of the technique has been increasing rapidly. However, the usefulness of this approach remains limited by the availability of molecular data. Here, I employed gene sequence data from the D2 region of the large subunit of ribosomal DNA to link adults of the tapeworm Clistobothrium carcharodoni Dailey and Vogelbein, 1990 (Cestoda: Tetraphyllidea) to larvae for which sequence data for this gene are available. The sequences from the adult tapeworms were genetically identical (0% sequence divergence) to those available on GenBank for "SP" 'small' Scolex pleuronectis recovered from the striped dolphin (Stenella coeruleoalba) and Risso's dolphin (Grampus griseus). This study is the first to provide empirical evidence linking the trophic interaction between great white sharks and cetaceans as a definitive route for the successful transmission of a tetraphyllidean tapeworm. Using the intensity of infection data from this shark and from cetaceans as proxies for the extent of predation, I estimate that this individual shark would have consumed between 9 to 83 G. griseus , fresh, dead, or both, in its lifetime.  相似文献   

5.
Life-cycle studies were conducted on 2 molecular strains of Mesocestoides tapeworms that represent different evolutionary lineages (clades A and B). Wild carnivores, reptiles, and rodents were examined for tapeworm infections at 2 enzootic sites: (1) San Miguel Island (SMI), a small island off the coast of southern California and (2) Hopland Research and Extension Center (HREC), a field station in northern California. Results indicate that deer mice (Peromyscus maniculatus) and coyotes (Canis latrans) may play an important role in the life cycles of Mesocestoides (clades A and B) in California. Over half the coyotes at HREC and at least a third of the population of island fox (Urocyon littoralis) at SMI were found to harbor clade A adult Mesocestoides spp. One of every 4 Mesocestoides-infected coyotes had tapeworms representing both clades A and B. Experimental inoculations revealed that proglottids (clades A and B) were not directly infectious to rodents, reptiles, or dogs. On the other hand, mice, lizards, and hamsters fed tetrathyridia of Mesocestoides spp. (clades A or B) developed peritoneal tetrathyridial infections. A dog that was fed tetrathyridia (clade B) developed an adult tapeworm infection. Acephalic metacestodes given orally to western fence lizards, laboratory mice, or domestic dogs did not result in metacestode or adult tapeworm infections. Whereas most clade A acephalic metacestodes from dogs were asexually proliferative, clade A tetrathyridia isolated from wild deer mice did not show evidence of asexual replication. Our study supports the hypothesis that a second, as of yet unidentified, intermediate host is necessary to complete the life cycles of Mesocestoides spp., and that acephalic metacestodes represent an aberrant form, incapable of further development.  相似文献   

6.
通过PCR方法扩增了青海湖裸鲤体腔寄生舌状绦虫18S rRNA、COⅠ和COB基因部分序列, 并进行分子鉴定, 分析了3种基因的同源性, 利用这3种基因进行分子进化和系统发育研究。结果显示, 经过分子鉴定, “面条样”绦虫为肠舌状绦虫, 克隆的18S rRNA、COⅠ和COB基因序列分别与AF254121(中国)、AF153910(中国)和JQ279109(阿尔及利亚)的核苷酸序列同源性为100.00%、99.49%和93.32%。同时, 利用GenBank中其他种属绦虫的18S rRNA、COⅠ和COB基因序列构建系统发育树, 均与已鉴定的肠舌状绦虫聚在同一支上, 且与肠舌状绦虫中国广州分离株种属亲缘关系较近, 与其他绦虫所属分支相距较远。初步阐明了鉴定的肠舌状绦虫分离株与其他种属之间的系统发育关系。  相似文献   

7.
European chub Leuciscus cephalus collected from five localities in the lowland and subalpine regions of Austria were analysed for oestrogenic effects of endocrine-disrupting chemicals and the presence of the plerocercoid of the tapeworm Ligula intestinalis. Of 1494 chub analysed, only seven (six males, one female) were found to be infected with single, but large plerocercoids up to 15 cm in length. Ligula-infected fish showed comparatively immature gonads, as demonstrated by the gonadosomatic index and gamete developmental stages. Plasma levels of the egg precursor protein vitellogenin also showed concentrations ranging below the detection limit. The present results indicate that chub infected with L. intestinalis and exposed to exogenous oestrogenic compounds can result in reduced gonadal maturation and produce false oestrogen-positive diagnoses in male fish. For plasma vitellogenin levels, L. intestinalis infections can result in false oestrogen-negative diagnoses in male and female fish.  相似文献   

8.
The life history of the trematode blood fluke, Sanguinicola klamathensis was studied using experimentally infected cutthroat trout (Salmo clarki) and by examining wild salmonid populations. This study was carried out at the Hagerman National Fish Hatchery, Idaho, during 1971–1973. Ova, miracidia, sporocysts, cercariae, immature flukes, and adult flukes were measured, described, and photographed. A life cycle for the blood fluke is presented.  相似文献   

9.
Infection of the whale tapeworm Diplogonoporus balaenopterae (Diphyllobothriidae) is occasionally found in humans, especially among Japanese. In the present study, we analysed the nucleotide sequences of the 18S rDNA, ITS1 and cox1 genes of the immature and mature proglottids of Diplogonoporus species recovered from five Japanese patients. The nucleotide sequences of 18S rDNA, ITS1 and cox1 showed little, if any, intraspecific divergence. Phylogenetic analyses of several diphyllobothriid species revealed a close relationship of Diplogonoporus isolates with the cetacean tapeworm Diphyllobothrium stemmacephalum. The results suggest that the genus Diphyllobothrium is paraphyletic and raise a question regarding the validity of the genus Diplogonoporus.  相似文献   

10.
In 1971, 1983 and 1984, ectoparasites were identified on 61 ring-necked pheasants (Phasianus colchicus) from Nebraska. Birds were collected throughout the state from 11 of 93 counties. Four species of chewing lice (Mallophaga) were collected: Lipeurus maculosus, Goniodes colchici, Lagopoecus colchicus and Amyrsidea megalosoma. One species of analgid mite, Megninia sp. was collected. Apparently, this species is new and undescribed. The four mallophagan species have not been reported from Nebraska.  相似文献   

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