Molecular phylogenetics and diagnosis of Anisakis, Pseudoterranova, and Contracaecum from northern Pacific marine mammals.
01 Dec 2005-Journal of Parasitology (American Society of Parasitologists)-Vol. 91, Iss: 6, pp 1413-1429
TL;DR: Phylogenetic analysis of LSU sequences revealed strong support for the monophyly of Anisakinae, Contracaecum plus Phocascaris, Pseudoterranova, and Anisakis, which is primarily consistent with previously published phenograms based on multilocus electrophoretic data.
Abstract: Individual specimens of Anisakis, Pseudoterranova, and Contracaecum collected from marine mammals inhabiting northern Pacific waters were used for comparative diagnostic and molecular phylogenetic analyses. Forty-eight new sequences were obtained for this study of 14 Anisakis taxa, 8 Pseudoterranova taxa, 4 Contracaecum taxa, and 4 outgroup species. Partial 28S (LSU) and complete internal transcribed spacer (ITS-1, 5.8S, ITS-2) ribosomal DNA was amplified by the polymerase chain reaction and sequenced. Sequences of ITS indicated that Pseudoterranova specimens from Zalophus californianus (California sea lion), Mirounga angustirostris (northern elephant seal), Phoca vitulina (harbor seal), Enhydra lutris (sea otter), and Eumetopias jubatus (Steller's sea lion) exactly matched P. decipiens s. str., extending the host and geographic range of this species. Anisakis from northern Pacific marine mammals were most closely related to members of the A. simplex species complex. Comparison of Anisakis ITS sequences diagnosed the presence of A. simplex C in 2 M. angustirostris hosts, which is a new host record. Anisakis specimens from Phocoena phocoena (harbor porpoise), Lissodelphis borealis (Pacific rightwhale porpoise), and E. jubatus included 3 ITS sequences that did not match any known species. Contracaecum adults obtained from Z. californianus were most closely related to C. ogmorhini s.l. and C. rudolphii, but ITS sequences of these Contracaecum specimens did not match C. ogmorhini s. str. or C. margolisi. These novel Anisakis and Contracaecum ITS sequences may represent previously uncharacterized species. Phylogenetic analysis of LSU sequences revealed strong support for the monophyly of Anisakinae, Contracaecum plus Phocascaris, Pseudoterranova, and Anisakis. Phylogenetic trees inferred from ITS sequences yielded robustly supported relationships for Pseudoterranova and Anisakis species that are primarily consistent with previously published phenograms based on multilocus electrophoretic data.
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01 Jan 2011
TL;DR: It is suggested that pathogenicity for humans is different among the Anisakis siblings, providing a possible explanation for uneven disease records worldwide and the possibility of a changing risk of anisakidosis in the time of climate change.
Abstract: Parasitic nematodes are known as important pathogens that cause problems for human and animal health. Some of them naturally inhabit the marine environment, where they are widespread and can be found in a variety of different hosts. Food-borne zoonoses via aquatic animals are most often linked to anisakid nematodes of the genera Anisakis Dujardin, 1845, Contracaecum Railliet and Henry, 1912, and Pseudoterranova Mozgovoi, 1951. These are commonly found in the digestive tract of marine mammals, and infect aquatic invertebrates and vertebrates as intermediate hosts. The most widely distributed whale worms Anisakis spp. involve cetaceans as final and planktonic copepods, euphausiids, squids and teleosts as intermediate or paratenic hosts. Painful infections of the digestive tract in humans originate through consumption of raw or semi-raw fisheries products, for example fish and squid. Recent molecular studies revealed the existence of morphologically similar but genetically different cryptic species (‘sibling species’) within the anisakids. Among these, A. simplex (s.s.) is responsible for the highest number of recorded human infections. Molecular studies of Anisakis larvae from various parts of the world Oceans demonstrate an uneven species distribution, with A. simplex (s.s.) being limited to the northern hemisphere. Another species, A. typica, has not yet been connected to this disease, and seems to be restricted to the tropical regions. This chapter presents the present state of knowledge about this widespread group of fish parasites, including the importance as human pathogens, their life cycle biology, biogeography and phylogeny. The distribution of the currently recognized Anisakis species is summarized and combined with the number of known cases of human anisakiasis. We suggest that pathogenicity for humans is different among the Anisakis siblings, providing a possible explanation for uneven disease records worldwide. The possibility of a changing risk of anisakidosis in the time of climate change is discussed.
101 citations
Cites background from "Molecular phylogenetics and diagnos..."
...…very similar but genetically different, having distinct host preferences, life cycles and geographical distribution (e.g. Mattiucci et al. 1997, 2005; Zhu et al. 2002; Nadler et al. 2005; Marques et al. 2006; D’Amelio et al. 2007; Klimpel et al. 2007, 2008, 2010; Mattiucci and Nascetti 2008)....
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...…5.8S rDNA region; direct sequencing of the 28S (LSU rDNA) and complete internal transcribed spacer (ITS1, 5.8S, ITS-2) rDNA (e.g. Li et al. 2005; Nadler et al. 2005; Zhu et al. 2000a, b, 2001, 2002) and mitochondrial cytochromoxidase 1 and 2 (mtDNA cox1, cox2) sequence analyses (e.g. Valentini…...
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TL;DR: Clinical symptoms associated with the infection, termed anisakidosis, vary from irritation of the oesophagus and stomach, via nausea, vomiting and diarrhoea to severe epigastric and abdominal pain.
99 citations
Cites background from "Molecular phylogenetics and diagnos..."
...Fishborne larval nematodes belonging to the family Anisakidae are widespread in fish populations worldwide (Nadler et al., 2005; Mattiucci and Nascetti, 2008; Karpiej et al., 2013)....
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TL;DR: Morphological and morphological data indicate that the new species belongs to the ‘ziphidarum-group’; however, it is genetically very distinct from A. ziphidareum, and the parallelism between the clade formed by these two anisakine taxa further supports the hypothesis of host–parasite co-evolutionary relationships.
Abstract: A new anisakid nematode, Anisakis nascettii n. sp., is described from beaked whales Mesoplodon spp. off the coast of New Zealand and South Africa. Morphological and molecular (allozymes and mtDNA cox2 sequence) data were used for diagnostic and identification purposes. Among the 19 allozymes studied, 10 were found to be unique and characteristic for A. nascettii n. sp. Analysis of allozymes demonstrated reproductive isolation from A. ziphidarum Paggi, Nascetti, Webb, Mattiucci, Cianchi & Bullini, 1998 and mtDNA cox2 sequences depict this Anisakis species as a distinct and unique entity. Key morphological diagnostic traits for A. nascettii with respect to the genetically closely related species A. ziphidarum include: spicule length, the spicule/body length ratio, the arrangement of the caudal papillae and the shape of the plectanes of the adult males. Genetic data confirmed that Anisakis sp. A of Pontes et al. (2005), which was partly described by Iglesias et al. (2008), and Anisakis sp. of Valentini et al. (2006) are conspecific with A. nascettii. Both molecular and morphological data indicate that the new species belongs to the ‘ziphidarum-group’; however, it is genetically very distinct from A. ziphidarum (DNei = 0.69, K2P = 0.09), as well as from all of the previously genetically characterised Anisakis spp. All tree topologies inferred by different methods (MP, NJ and Bayesian) support the finding that A. nascettii n. sp. and A. ziphidarum are sister-species. It is also confirmed that A. nascettii n. sp. is, at the adult stage, a parasite of beaked whales of the genus Mesoplodon, whereas, as a larva, it has been identified from the squid Moroteuthis ingens Smith. Furthermore, Mesoplodon bowdoini Andrews represents a new host record for A. ziphidarum. The parallelism between the clade formed by these two anisakine taxa, i.e. A. ziphidarum and A. nascettii, and that formed by their definitive hosts further supports the hypothesis of host–parasite co-evolutionary relationships, as previously suggested for Anisakis spp. and their cetacean hosts.
96 citations
Cites background from "Molecular phylogenetics and diagnos..."
...…et al., 2006), was included as an outgroup to root the Anisakis phylogenetic trees, based on the relationships of Anisakis spp. and Pseudoterranova spp. previously demonstrated in ribosomal and mitochondrial DNA analyses (Nadler & Hudspeth, 2000; Nadler et al., 2005, 2007; Valentini et al., 2006)....
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...pegreffii is also well supported by a phylogenetic analysis inferred from ITS rDNA sequence data-sets (Nadler et al., 2005)....
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...The clade including A. simplex (s.s.), A. simplex C and A. pegreffii is also well supported by a phylogenetic analysis inferred from ITS rDNA sequence data-sets (Nadler et al., 2005)....
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TL;DR: Auranofin, a gold-containing drug used for rheumatoid arthritis, was effective in vitro in killing both Brugia spp.
Abstract: Two major human diseases caused by filariid nematodes are onchocerciasis, or river blindness, and lymphatic filariasis, which can lead to elephantiasis. The drugs ivermectin, diethylcarbamazine (DEC), and albendazole are used in control programs for these diseases, but are mainly effective against the microfilarial stage and have minimal or no effect on adult worms. Adult Onchocerca volvulus and Brugia malayi worms (macrofilariae) can live for up to 15 years, reproducing and allowing the infection to persist in a population. Therefore, to support control or elimination of these two diseases, effective macrofilaricidal drugs are necessary, in addition to current drugs. In an effort to identify macrofilaricidal drugs, we screened an FDA-approved library with adult worms of Brugia spp. and Onchocerca ochengi, third-stage larvae (L3s) of Onchocerca volvulus, and the microfilariae of both O. ochengi and Loa loa. We found that auranofin, a gold-containing drug used for rheumatoid arthritis, was effective in vitro in killing both Brugia spp. and O. ochengi adult worms and in inhibiting the molting of L3s of O. volvulus with IC50 values in the low micromolar to nanomolar range. Auranofin had an approximately 43-fold higher IC50 against the microfilariae of L. loa compared with the IC50 for adult female O. ochengi, which may be beneficial if used in areas where Onchocerca and Brugia are co-endemic with L. loa, to prevent severe adverse reactions to the drug-induced death of L. loa microfilariae. Further testing indicated that auranofin is also effective in reducing Brugia adult worm burden in infected gerbils and that auranofin may be targeting the thioredoxin reductase in this nematode.
78 citations
TL;DR: Data revealed higher intensities in anisakid infections in Antarctic and sub-Antarctic hosts, presumably resulting from a lower degree of habitat disturbance in less stressed areas, and suggests that an isakid nematodes, and their levels of genetic diversity, may be suitable indicators of the integrity of marine food webs and of the general biodiversity of a marine ecosystem.
76 citations
References
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TL;DR: The program MODELTEST uses log likelihood scores to establish the model of DNA evolution that best fits the data.
Abstract: Summary: The program MODELTEST uses log likelihood scores to establish the model of DNA evolution that best fits the data. Availability: The MODELTEST package, including the source code and some documentation is available at http://bioag.byu.edu/zoology/crandall―lab/modeltest.html. Contact: dp47@email.byu.edu.
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TL;DR: The effects on phylogenetic accuracy of adding characters and/or taxa were explored using data generated by computer simulation using a four-taxon tree representing a difficult phylogenetic problem with an extreme situation of long branch attraction.
Abstract: The effects on phylogenetic accuracy of adding characters and/or taxa were explored using data generated by computer simulation. The conditions of this study were constrained but allowed for systematic investigation of certain parameters. The starting point for the study was a four-taxon tree in the ``Felsenstein zone,'' representing a dif® cult phylogenetic problem with an extreme situation of long branch attraction. Taxa were added sequentially to this tree in a manner speci® cally designed to break up the long branches, and for each tree data matrices of different sizes were simulated. Phylogenetic trees were reconstructed from these data using the criteria of parsimony and maximum likelihood. Phylogenetic accuracy was measured in three ways: (1) proportion of trees that are completely correct, (2) proportion of correctly reconstructed branches in all trees, and (3) proportion of trees in which the original four-taxon statement is correctly reconstructed. Accuracy improved dramatically with the addition of taxa and much more slowly with the addition of characters. If taxa can be added to break up long branches, it is much more preferable to add taxa than characters. (Long branch attraction; parsimony; phylogenetic recon- struction; simulation; taxon sampling.)
687 citations
01 Jan 1998
TL;DR: In this paper, the effects of adding characters and/or taxa on phylogenetic accuracy were explored using data generated by computer simulation using a four-taxon tree in the "Felsenstein zone/7".
Abstract: The effects on phylogenetic accuracy of adding characters and/or taxa were explored using data generated by computer simulation. The conditions of this study were constrained but allowed for systematic investigation of certain parameters. The starting point for the study was a four-taxon tree in the "Felsenstein zone/7 representing a difficult phylogenetic problem with an extreme situation of long branch attraction. Taxa were added sequentially to this tree in a manner specifically designed to break up the long branches, and for each tree data matrices of different sizes were simulated. Phylogenetic trees were reconstructed from these data using the criteria of parsimony and maximum likelihood. Phylogenetic accuracy was measured in three ways: (1) proportion of trees that are completely correct, (2) proportion of correctly reconstructed branches in all trees, and (3) proportion of trees in which the original four-taxon statement is correctly reconstructed. Accuracy improved dramatically with the addition of taxa and much more slowly with the addition of characters. If taxa can be added to break up long branches, it is much more preferable to add taxa than characters. (Long branch attraction; parsimony; phylogenetic recon? struction; simulation; taxon sampling.) It is obvious that the successful recon? struction of phylogenetic relationships re? quires some amount of data sampling from relevant taxa and informative char? acters. Far less clear, however, is how much of each data type is required, and whether one of those sources of data has a greater impact on accuracy than the other. Given limited time and resources, it is important to explore the costs and benefits to phylo? genetic accuracy of adding taxa versus in? creasing the number of characters. For ex? ample, given that one has sufficient time and resources to sequence 10 kilobases (kb) of DNA, would it be better to se? quence, say, 2.5 kb from each of 4 taxa, or 1 kb from each of 10, or 0.25 kb from each of 40?
676 citations
TL;DR: More than 260 specimens of fish, belonging to 64 species, have been searched for nematode parasites and 9 species of fish were found to be free of nematodes.
Abstract: The present paper deals with nematode parasites from some Norwegian marine fishes. The major part of the material was collected personally from fishes caught in the fjords near Bergen and Tromso; the minor part of the material was obtained from the zoological museums in Oslo and Bergen and from other sources. 260 specimens of fish, belonging to 64 species, have been searched for nematode parasites. 9 species of fish were found to be free of nematodes.
373 citations
"Molecular phylogenetics and diagnos..." refers background in this paper
...…A. simplex s. str.) A. simplex C); these represent the 3 known species within the A. simplex species complex and are characterized (along with A. typica and A. ziphidarum) by having type I larvae sensu Berland (1961), which may represent the apomorphic (derived) state within An- NADLER ET AL....
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TL;DR: The polymorphisms obtained by restriction fragment length polymorphisms have provided a new set of genetic markers for the accurate identification of sibling species and morphospecies.
297 citations