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1. The Temnocephalidae (Platyhelminthes): molecular data illuminate the evolution of an ancient group of symbiotic flatworms.

Author

Blair, David, Cannon, Lester R.G., Littlewood, D. Timothy J., Olson, Peter D., and Sewell, Kim B.

Subjects
RIBOSOMAL RNA, MOLECULAR phylogeny, PLATYHELMINTHES, CRAYFISH, CRUSTACEA, SPECIES
Abstract

The Temnocephalidae sensu Van Steenkiste et al., 2021 is a diverse group of rhabdocoel flatworms that are ectosymbiotic mostly on freshwater crustaceans. The family is found on all inhabited continents except for N. America (north of Mexico) and Africa. Here, we explore the systematic implications of a molecular phylogeny inferred from partial sequences of the nuclear 18S and 28S ribosomal RNA genes. In agreement with previous views based on morphology, the earliest diverging group within the family was exemplified by the genus Scutariella (subfamily Scutariellinae) followed by the genus Didymorchis (Didymorchinae). The genus Dactylocephala from Madagascar, previously thought to be in the Temnocephalinae, then diverged as sister to the remaining temnocephalids. A new subfamily, Dactylocephalinae, is proposed to contain this genus. Remaining subfamilies were, in turn, Diceratocephalinae, Actinodactylellinae and Temnocephalinae. Further subdivision was apparent within the Temnocephalinae. One well-supported clade included the genera Temnohaswellia (eastern Australia and New Zealand), Temnomonticellia (Tasmania) and Temnocephala (South America). The widespread genus Temnosewellia (= Ts.) was not supported as monophyletic. One clade of Temnosewellia sensu lato included numerous species known primarily from crayfish of the genus Euastacus, found in eastern and south-eastern Australia. Two other clades circumscribed the taxa Ts. minor and Ts. dendyi. Identities and membership of these two clades are clouded by frequent misidentifications, the reasons for which are discussed here. A fourth clade of Temnosewellia s.l. included Ts. rouxi and other taxa from northern Australia and Asia (ranging at least from Japan to India). The diversity of temnocephalids in Australia, and especially in Asia, is greatly underappreciated. Some general comments are made about geographic distribution of temnocephalids, but detailed biogeographic analysis requires broader sampling. [ABSTRACT FROM AUTHOR]

Published
2023
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2. Jumping continents and major host lineages: phylogeny and diversity of the enigmatic Cryptotropidae (Platyhelminthes: Digenea).

Author

Tkach, Vasyl V, Chermak, Taylor P, Patitucci, Kaylyn K, Greiman, Stephen E, Binh, Tran Thi, and Olson, Peter D

Subjects
PHYLOGENY, PLATYHELMINTHES, MOLECULAR phylogeny, DNA sequencing, CONTINENTS, DIGENEA
Abstract

Members of several genera in the digenean superfamily Microphalloidea, namely Renschetrema , Rohdetrema , Cryptotropa , Cephalouterina and Pseudocryptotropa , are characterized by an unusual dorsal position of the genital atrium. In the absence of phylogenetic data, their systematic position has been unstable. In the most recent taxonomic revision of the Microphalloidea, they were housed in three different families. We studied the morphology and obtained DNA sequences of several microphallolideans with a dorsal genital pore, collected from vertebrates in Southeast Asia and South America. We used sequences of the nuclear 28S gene to infer a superfamily-level phylogeny and sequences of the mitochondrial cox1 gene for family-level phylogeny and species-level comparisons. Based on the combination of molecular phylogenetic data and morphological features, we restore the Cryptotropidae and synonymize the Renschetrematidae with the Cryptotropidae. We erect new genera Paracryptotropa gen. nov. and Armadoatrium gen. nov. , provide amended diagnoses of the Cryptotropidae and Renschetrema and provide keys to the identification of genera within the family. We resurrect the genus Novetrema , previously synonymized with Pseudocryptotropa , and remove Renschetrema indicum from Renschetrema. We describe four new species from lizards in Vietnam and birds in the Philippines and Peru. The unique morphological features and unusually broad host associations and geographical distributions of cryptotropids are discussed. [ABSTRACT FROM AUTHOR]

Published
2023
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4. Gyrocotyle discoveryi Bray & Waeschenbach & Littlewood & Halvorsen & Olson 2020, n. sp

Author

Bray, Rodney A., Waeschenbach, Andrea, Littlewood, D. Timothy J., Halvorsen, Odd, and Olson, Peter D.

Subjects
Gyrocotylidae, Animalia, Cestoda, Gyrocotyle discoveryi, Biodiversity, Platyhelminthes, Gyrocotyle, Taxonomy, Gyrocotylidea
Abstract

Gyrocotyle discoveryi n. sp. Type-host: Hydrolagus mirabilis (Collett) (Chimaeriformes: Chimaeridae), large-eyed rabbitfish. Type-locality: Goban Spur, North-East Atlantic. Other localities: Porcupine Seabight (51��09 0 N, 11��55 0 W, depth 1,200 m, 30.xi.2002, RRS Discovery Cruise, No. 15048-14, 15); Goban Spur (49��49 0 N, 11��44 0 W, depth 1,175���1,250 m, 27.iv.2001, RRS Discovery Cruise 252, No. 13963/17, 20, 24, 72; 49��41 0 N, 11��53 0 W, depth 1,053���1,077 m, 23.iv.2001, RRS Discovery Cruise 252, No. 13962/4; 49��47 0 N, 11��58 0 W, depth 1,240���1,360 m, 19.x.2002, RRS Discovery Cruise D 266, No. 15066-124, 125; 51��09 0 N, 11��55 0 W, depth 1200 m, 30.ix.2002, RRS Discovery Cruise D 266, No. 15063-103), North-East Atlantic. Type-material: Holotype (NHMUK 2019.11.21.3), paratypes (NHMUK.2019.11.21.4-13 from Goban Spur; NHMUK.2019.11.21.14-19 from Porcupine Sea Bight).). Site in host: Spiral intestine. Representative DNA sequences: MN655879 and MN655881 (ssrDNA); MN657003-MN657005, MN657007- MN657009, MN657011 (lsrDNA, domains D1-D3). ZooBank registration: The Life Science Identifier (LSID) for Gyrocotyle discoveryi n. sp. is urn:lsid:- zoobank.org:act:7B028A0B-B8EB-495E-A9F1- F29DDB60B89A. Etymology: The species is named after the RRS Discovery, the NERC research vessel on which the specimens were collected. Description [Based on 17 specimens; Figs. 4���6.] With characters of the order. Body relatively squat, with deeply crenulated margins, 8,634 ���17,586 X 4,996 ���8,439 (12,071 X 6,676), width 36���98 (60)% of length. Anterior sucker distinct, 1,149 ���1,621 (1,347) long, 596���1,022 (771) wide. Uterus large, in central part of body, 1,546 ���2,996 (2,232) from anterior extremity, 2,453 ���6,226 (4,533) long, 35���43 (38)% of body length. Rosette distinct, fairly complex, 1,797 ���3,092 (2,575) long, junction with soma not clear. Eggs tanned, operculate, 85��� 97 X 39���56 (89 X 49). Diagnosis Gyrocotyle discoveryi n. sp. can be diagnosed from other congeners on the basis of unique nucleotide characters in our rDNA alignments (listed as alignment position-nucleotide): ssrDNA: 176-G, 782-G, 862-G, 973-C; lsrDNA: 573-A, 800-T, 1,245-C, 1,246- C, 1,247-G, 1,360-T, 1,369-T, 1,375-C, 1,379-G, 1,382-G, 1,391-A, 1,449-T, 1,468-T, 1,477-T. Remarks Mauchline & Gordon (1984) reported a ������cestode������ in Hy. mirabilis from the Rockall Trough off NW Scotland, which is, as far as we are aware, the only possible record of a Gyrocotyle from this host. Two species of Gyrocotyle, G. major van der Land & Templeman, 1968 and G. abyssicola van der Land & Templeman, 1968, have been reported from its congener, the small-eyed rabbit fish Hydrolagus affinis (de Brito Capello) on the edges of the continental shelf off the eastern coast of Newfoundland (van der Land & Templeman, 1968). These two species are illustrated as much more elongate than our specimens, with less complex lateral wrinkling and small rosettes. The worms were recovered from frozen hosts, so the gross morphology may well not be of significance in differentiating these species. Subsequently, these two taxa have been reported from the same host species off south-western Greenland by Karlsbakk et al. (2002) and, puzzlingly, from a rhinochimaerine species, the straight-nosed rabbit fish Rhinochimaera atlantica Holt & Byrne, off the Scotian Shelf by Hogans & Hurlbut (1984). In the North-East Atlantic, R. atlantica has not been found harbouring Gyrocotyle, but it does harbour the strobilate tapeworm Chimaerocestos prudhoei Williams & Bray, 1984 and a congeneric host, the Pacific spookfish R. pacifica (Mitsukuri, 1895) also harbours a species of Chimaerocestos Williams & Bray, 1984 (see Caira et al., 1999, 2014). Other records of Gyrocotyle spp. from Hydrolagus spp. are from the Pacific Ocean (see Bandoni & Brooks, 1987). There are no reliable morphological characters to differentiate this species or indeed any of the gyrocotylidean species circumscribed by molecular means. Therefore, the species is diagnosed by its relatively marked sequence divergence from those of recognised species., Published as part of Bray, Rodney A., Waeschenbach, Andrea, Littlewood, D. Timothy J., Halvorsen, Odd & Olson, Peter D., 2020, Molecular circumscription of new species of Gyrocotyle Diesing, 1850 (Cestoda) from deep-sea chimaeriform holocephalans in the North Atlantic, pp. 285-296 in Systematic Parasitology 97 on pages 292-293, DOI: 10.1007/s11230-020-09912-w, http://zenodo.org/record/4623814, {"references":["Mauchline, J., & Gordon, J. D. M. (1984). Incidence of parasitic worms in stomachs of pelagic and demersal fish of the Rockall Trough, northeastern Atlantic Ocean. Journal of Fish Biology, 24, 281 - 285.","van der Land, J., & Templeman, W. (1968). Two new species of Gyrocotyle (Monogenea) from Hydrolagus affinis (Brito Capello) (Holocephali). Journal of the Fisheries Research Board of Canada, 11, 2365 - 2385.","Karlsbakk, E., Aspholm, P. E., Berg, V., Hareide, N. R., & Berland, B. (2002). Some parasites of the small-eyed rabbitfish, Hydrolagus affinis (Capello, 1867) (Holocephali), caught in deep waters off SW Greenland. Sarsia, 87, 179 - 184.","Hogans, W. E., & Hurlbut, T. R. (1984). Parasites of the knifenose chimaera, Rhinochimaera atlantica, from the northwest Atlantic Ocean. Canadian Field-Naturalist, 98, 365.","Williams, H. H., & Bray, R. A. (1984). Chimaerocestos prudhoei gen. et sp. nov., representing a new family of tetraphyllideans and the first record of strobilate tapeworms from a holocephalan. Parasitology, 88, 105 - 116.","Caira, J. N., Jensen, K., & Healy, C. J. (1999). On the phylogenetic relationships among tetraphyllidean, lecanicephalidean and diphyllidean tapeworm genera. Systematic Parasitology, 42, 77 - 151.","Caira, J. N., Jensen, K., Waeschenbach, A., Olson, P. D., & Littlewood, D. T. J. (2014). Orders out of chaos - molecular phylogenetics reveals the complexity of shark and stingray tapeworm relationships. International Journal for Parasitology, 44, 55 - 73.","Bandoni, S. M., & Brooks, D. R. (1987). Revision and phylogenetic analysis of the Gyrocotylidea Poche, 1926 (Platyhelminthes: Cercomeria: Cercomeromorpha). Canadian Journal of Zoology, 65, 2369 - 2389."]}

Published
2020
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5. Gyrocotyle haffii Bray & Waeschenbach & Littlewood & Halvorsen & Olson 2020, n. sp

Author

Bray, Rodney A., Waeschenbach, Andrea, Littlewood, D. Timothy J., Halvorsen, Odd, and Olson, Peter D.

Subjects
Gyrocotyle haffii, Gyrocotylidae, Animalia, Cestoda, Biodiversity, Platyhelminthes, Gyrocotyle, Taxonomy, Gyrocotylidea
Abstract

Gyrocotyle haffii n. sp. Type-host: Harriotta raleighana Goode & Bean (Chimaeriformes: Rhinochimaeridae), bent-nosed chimaera. Type-locality: Goban Spur (49°46 0 N, 12°21 0 W, depth 1,631–1,653 m, 22-23.iv.2001; RRS Discovery Cruise 252, No. 13951/14), North-East Atlantic. Type-material: Holotype (NHMUK. 2019.11.21.1), paratype (NHMUK. 2019.11.21.2). Site in host: Spiral intestine. Representative DNA sequences: MN655880 (ssrDNA); MN657006 (lsrDNA, domains D1-D3). ZooBank registration: The Life Science Identifier (LSID) for Gyrocotyle haffii n. sp. is urn:lsid:- zoobank.org:act:7717F9D6-4C9D-4C59-8D0A- 4C5E306B4671. Etymology: The species is named in honour of our late colleague and friend Professor Harford ‘Haffi 0 Williams in recognition of his contribution to the understanding of the Gyrocotylidea. Description [Based on a single intact, immature whole worm and second immature worm from which the central portion had been excised for molecular analysis; Figs. 2, 3]. With characters of the order. Body elongate with minute annular ridges; no large lateral flap. Length 23,504; greatest width near anterior extremity, 3,131. Rosette relatively small with few crenulations, 1,943 long. Anterior sucker large, oval, 1,750 X 1,223. Reproductive system immature; anlagen commences 2,852 from anterior extremity, 8,191 long; consisting of a long, narrow patch of stained tissue reaching, and a branched section passing, towards lateral margin of worm; apparently opening at c. 268 from anterior extremity. Only other evidence of reproductive organs is putative vitelline glands scattered around posterior extremity of anlagen. Diagnosis Gyrocotyle haffii n. sp. can be diagnosed from other congeners on the basis of unique nucleotide characters in our rDNA alignments (listed as alignment positionnucleotide): ssrDNA: 218-T, 723-A, 746-C, 747-A, 748-G, 1,158-T, 1,654-G, 1,673-C, 2,115-C; lsrDNA: 612-T, 837-A, 875-T, 1,306-A, 1,395-C, 1,402-A, 1,501-G. Remarks As far as we are aware there is only one previous report of a gyrocotylidean from Ha. raleighana, the bentnose chimaera. Parukhin (1966) reported ‘‘ Gyrocotyloides nybelini Fuhrmann, 1931 ’’ in this host from the South Atlantic Ocean. Parukhin (1968) repeated this report saying (in translation) ‘‘Found in Callorhynchus capensis. Two adult parasites were found in two fish. In addition, six larvae were found in one of them. In addition to C. capensis, specimens were found in two Hariota [sic] raleighana. In both cases there were two specimens. Previously, this species was observed in the Atlantic in Chimaera monstrosa ’’. In addition, it seems likely that the records of ‘cestode adults 0 from Ha. raleighana, Hy. mirabilis and C. monstrosa from the Rockall Trough off NW Scotland by Mauchline & Gordon (1984) refer to Gyrocotyle spp. There is no reliable morphological character to differentiate this species or indeed any of the gyrocotylidean species circumscribed by molecular means. Therefore, the species is diagnosed by its relatively marked sequence divergence from those of recognised species.

Published
2020
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6. Comparative analysis of Wnt expression identifies a highly conserved developmental transition in flatworms

Author

Koziol, Uriel, Jarero, Francesca, Olson, Peter D., Brehm, Klaus, and Koziol, Uriel. Universidad de la República (Uruguay). Facultad de Ciencias. Instituto de Biología

Subjects
Planarian, SFRP, Agricultural and Biological Sciences(all), Metamorphosis, Biochemistry, Genetics and Molecular Biology(all), Cestodes, Metamorphosis, Biological, Gene Expression Regulation, Developmental, Helminth Proteins, Antero-posterior axis, Wnt Proteins, Wnt, Larva, parasitic diseases, Myocyte, Animals, Cestoda, Echinococcus multilocularis, Six3/6, ddc:610, Phylotypic, Platyhelminthes, FoxQ2, Hymenolepis, Research Article
Abstract

Background Early developmental patterns of flatworms are extremely diverse and difficult to compare between distant groups. In parasitic flatworms, such as tapeworms, this is confounded by highly derived life cycles involving indirect development, and even the true orientation of the tapeworm antero-posterior (AP) axis has been a matter of controversy. In planarians, and metazoans generally, the AP axis is specified by the canonical Wnt pathway, and we hypothesized that it could also underpin axial formation during larval metamorphosis in tapeworms. Results By comparative gene expression analysis of Wnt components and conserved AP markers in the tapeworms Echinococcus multilocularis and Hymenolepis microstoma, we found remarkable similarities between the early stages of larval metamorphosis in tapeworms and late embryonic and adult development in planarians. We demonstrate posterior expression of specific Wnt factors during larval metamorphosis and show that scolex formation is preceded by localized expression of Wnt inhibitors. In the highly derived larval form of E. multilocularis, which proliferates asexually within the mammalian host, we found ubiquitous expression of posterior Wnt factors combined with localized expression of Wnt inhibitors that correlates with the asexual budding of scoleces. As in planarians, muscle cells are shown to be a source of secreted Wnt ligands, providing an explanation for the retention of a muscle layer in the immotile E. multilocularis larva. Conclusions The strong conservation of gene expression between larval metamorphosis in tapeworms and late embryonic development in planarians suggests, for the first time, a homologous developmental period across this diverse phylum. We postulate these to represent the phylotypic stages of these flatworm groups. Our results support the classical notion that the scolex is the true anterior end of tapeworms. Furthermore, the up-regulation of Wnt inhibitors during the specification of multiple anterior poles suggests a mechanism for the unique asexual reproduction of E. multilocularis larvae. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0233-x) contains supplementary material, which is available to authorized users.

Published
2016

7. The genomes of four tapeworm species reveal adaptations to parasitism

Author

Tsai, Isheng J., Zarowiecki, Magdalena, Holroyd, Nancy, Garciarrubio, Alejandro, Sanchez-Flores, Alejandro, Brooks, Karen L., Tracey, Alan, Bobes, Raúl J., Fragoso, Gladis, Sciutto, Edda, Aslett, Martin, Beasley, Helen, Bennett, Hayley M., Cai, Jianping, Camicia, Federico, Clark, Richard, Cucher, Marcela, De Silva, Nishadi, Day, Tim A., Deplazes, Peter, Estrada, Karel, Fernández, Cecilia, Holland, Peter W. H., Hou, Junling, Hu, Songnian, Huckvale, Thomas, Hung, Stacy S., Kamenetzky, Laura, Keane, Jacqueline A., Kiss, Ferenc, Koziol, Uriel, Lambert, Olivia, Liu, Kan, Luo, Xuenong, Luo, Yingfeng, Macchiaroli, Natalia, Nichol, Sarah, Paps, Jordi, Parkinson, John, Pouchkina-Stantcheva, Natasha, Riddiford, Nick, Rosenzvit, Mara, Salinas, Gustavo, Wasmuth, James D., Zamanian, Mostafa, Zheng, Yadong, Sánchez-Flores, Alejandro, Cevallos, Miguel A., Morett, Enrique, González, Víctor, Portillo, Tobias, Ochoa-Leyva, Adrian, José, Marco V., Landa, Abraham, Jiménez, Lucía, Valdés, Víctor, Carrero, Julio C., Larralde, Carlos, Morales-Montor, Jorge, Limón-Lason, Jorge, Soberón, Xavier, Laclette, Juan P., Cai, Xuepeng, Olson, Peter D., Brehm, Klaus, Berriman, Matthew, University of Zurich, and Berriman, M

Subjects
10078 Institute of Parasitology, Proteome, parasitism, Ciencias de la Salud, Helminth genetics, Genome, 0302 clinical medicine, 600 Technology, Taenia solium, taenia-solium, Parasitología, infections, Molecular Targeted Therapy, Echinococcus granulosus, Conserved Sequence, Genes, Helminth, HSP70, 0303 health sciences, Multidisciplinary, biology, Ecology, Stem Cells, Genes, Homeobox, Cestode Infections, Adaptation, Physiological, Biological Evolution, 3. Good health, medicine.drug_formulation_ingredient, cultivation, granulosus, echinococcus-multilocularis, purl.org/becyt/ford/3 [https], Metabolic Networks and Pathways, Hymenolepis microstoma, CIENCIAS MÉDICAS Y DE LA SALUD, 030231 tropical medicine, Parasitism, 610 Medicine & health, heat-shock, Echinococcus multilocularis, Article, 03 medical and health sciences, purl.org/becyt/ford/3.3 [https], fluke schistosoma-mansoni, parasitic diseases, medicine, Animals, Humans, HSP70 Heat-Shock Proteins, Parasites, 030304 developmental biology, Synteny, Adaptation to Parasitism, Genome, Helminth, 1000 Multidisciplinary, cysticercosis, Tapeworm, biology.organism_classification, echinococcosis, Evolutionary biology, identification, Cestoda, 570 Life sciences, Platyhelminthes, Hymenolepis
Abstract

Tapeworms (Cestoda) cause neglected diseases that can be fatal and are difficult to treat, owing to inefficient drugs. Here we present an analysis of tapeworm genome sequences using the human-infective species Echinococcus multilocularis, E. granulosus, Taenia solium and the laboratory model Hymenolepis microstoma as examples. The 115- to 141-megabase genomes offer insights into the evolution of parasitism. Synteny is maintained with distantly related blood flukes but we find extreme losses of genes and pathways that are ubiquitous in other animals, including 34 homeobox families and several determinants of stem cell fate. Tapeworms have specialized detoxification pathways, metabolism that is finely tuned to rely on nutrients scavenged from their hosts, and species-specific expansions of non-canonical heat shock proteins and families of known antigens. We identify new potential drug targets, including some on which existing pharmaceuticals may act. The genomes provide a rich resource to underpin the development of urgently needed treatments and control. Fil: Tsai, Isheng J.. Wellcome Trust Genome Campus; Estados Unidos. University of Miyazaki; Japón Fil: Zarowiecki, Magdalena. Wellcome Trust Genome Campus; Estados Unidos Fil: Holroyd, Nancy. Wellcome Trust Genome Campus; Estados Unidos Fil: Garciarrubio, Alejandro. Universidad Nacional Autónoma de México; México Fil: Sanchez Flores, Alejandro. Wellcome Trust Genome Campus; Estados Unidos. Universidad Nacional Autónoma de México; México Fil: Camicia, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina Fil: Cucher, Marcela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina Fil: Kamenetzky, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina Fil: Macchiaroli, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina Fil: Rosenzvit, Mara Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina Fil: Liu, Kan. Chinese Academy of Sciences; República de China Fil: Luo, Xuenong. Chinese Academy of Agricultural Sciences; China Fil: Luo, Yingfeng. Chinese Academy of Sciences; República de China Fil: Nichol, Sarah. Wellcome Trust Genome Campus; Estados Unidos Fil: Paps, Jordi. University of Oxford; Reino Unido Fil: Parkinson, John. University of Toronto; Canadá Fil: Pouchkina Stantcheva, Natasha. Natural History Museum; Reino Unido Fil: Riddiford, Nick. Natural History Museum; Reino Unido Fil: Salinas, Gustavo. Universidad de la República; Uruguay Fil: Wasmuth, James D.. University of Calgary; Canadá Fil: Zamanian, Mostafa. McGill University; Canadá Fil: Zheng, Yadong. Chinese Academy of Agricultural Sciences; China Fil: The Taenia Solium Genome Consortium. No especifica; Fil: Cai, Xuepeng. Chinese Academy of Agricultural Sciences; China Fil: Soberón, Xavier. Universidad Nacional Autónoma de México; México. Instituto Nacional de Medicina Genómica; México Fil: Olson, Peter D.. Natural History Museum; Reino Unido Fil: Laclette, Juan P.. Universidad Nacional Autónoma de México; México Fil: Brehm, Klaus. Universität Würzburg; Alemania Fil: Berriman, Matthew. Wellcome Trust Genome Campus; Estados Unidos

Published
2013

8. Australian spiny mountain crayfish and their temnocephalan ectosymbionts: an ancient association on the edge of coextinction?

Author

Cuthill, Jennifer F. Hoyal, Sewell, Kim B., Cannon, Lester R. G., Charleston, Michael A., Lawler, Susan, Littlewood, D. Timothy J., Olson, Peter D., and Blair, David

Subjects
CRAYFISH, SYMBIOSIS, BIOLOGICAL extinction, PLATYHELMINTHES, CLIMATE change
Abstract

Australian spiny mountain crayfish (Euastacus, Parastacidae) and their ecotosymbiotic temnocephalan flatworms (Temnocephalida, Platyhelminthes) may have co-occurred and interacted through deep time, during a period of major environmental change. Therefore, reconstructing the history of their association is of evolutionary, ecological, and conservation significance. Here, time-calibrated Bayesian phylogenies of Euastacus species and their temnocephalans (Temnohaswellia and Temnosewellia) indicate nearsynchronous diversifications from the Cretaceous. Statistically significant cophylogeny correlations between associated clades suggest linked evolutionary histories. However, there is a stronger signal of codivergence and greater host specificity in Temnosewellia, which co-occurs with Euastacus across its range. Phylogeography and analyses of evolutionary distinctiveness (ED) suggest that regional differences in the impact of climate warming and drying had major effects both on crayfish and associated temnocephalans. In particular, Euastacus and Temnosewellia show strong latitudinal gradients in ED and, conversely, in geographical range size, with the most distinctive, northern lineages facing the greatest risk of extinction. Therefore, environmental change has, in some cases, strengthened ecological and evolutionary associations, leaving host-specific temnocephalans vulnerable to coextinction with endangered hosts. Consequently, the extinction of all Euastacus species currently endangered (75%) predicts coextinction of approximately 60% of the studied temnocephalans, with greatest loss of the most evolutionarily distinctive lineages. [ABSTRACT FROM AUTHOR]

Published
2016
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9. Description of Hymenolepis microstoma (Nottingham strain): a classical tapeworm model for research in the genomic era.

Author

Cunningham, Lucas J. and Olson, Peter D.

Subjects
*HYMENOLEPIS, *HYMENOLEPIDIDAE, *GENOMES, *GENETICS, *GENOMICS, *TAPEWORMS, *PLATYHELMINTHES, *BILIARY tract, *DOMESTIC animals
Abstract

Background: Hymenolepis microstoma (Dujardin, 1845) Blanchard, 1891, the mouse bile duct tapeworm, is a rodent/beetle-hosted laboratory model that has been used in research and teaching since its domestication in the 1950s. Recent characterization of its genome has prompted us to describe the specific strain that underpins these data, anchoring its identity and bringing the 150+ year-old original description up-to-date. Results: Morphometric and ultrastructural analyses were carried out on laboratory-reared specimens of the 'Nottingham' strain of Hymenolepis microstoma used for genome characterization. A contemporary description of the species is provided including detailed illustration of adult anatomy and elucidation of its taxonomy and the history of the specific laboratory isolate. Conclusions: Our work acts to anchor the specific strain from which the H. microstoma genome has been characterized and provides an anatomical reference for researchers needing to employ a model tapeworm system that enables easy access to all stages of the life cycle. We review its classification, life history and development, and briefly discuss the genome and other model systems being employed at the beginning of a genomic era in cestodology. [ABSTRACT FROM AUTHOR]

Published
2010
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10. Advances and Trends in the Molecular Systematics of the Parasitic Platyhelminthes.

Author

Olson, Peter D. and Tkach, Vasyl V.

Subjects
*PLATYHELMINTHES, *TAPEWORMS, *DIGENEA, *MONOGENEA, *BIOLOGICAL classification
Abstract

The article reports on the application of molecular systematics to the Platyhelminthes or the parasitic groups including Cestoda, Digenea and Monogenea. The molecular-based hypotheses are predominant in the field focusing on the systematics advancements, taxonomy, classification and phylogeny and other processes.

Published
2005
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11. Molecular phylogeny of gill monogeneans (Platyhelminthes, Monogenea, Dactylogyridae) and colonization of Indo-West Pacific butterflyfish hosts (Perciformes, Chaetodontidae).

Author

Plaisance, Laetitia, Littlewood, D. T imothy J., Olson, Peter D., and Morand, Serge

Subjects
MONOGENEA, PHYLOGENY, BIOLOGICAL evolution, PLATYHELMINTHES, PARASITES, PTEROIS volitans
Abstract

Plaisance, L., Littlewood, D. T. J., Olson, P. D. & Morand, S. (2005). Molecular phylogeny of gill monogeneans (Platyhelminthes, Monogenea, Dactylogyridae) and colonization of Indo-West Pacific butterflyfish hosts (Perciformes, Chaetodontidae). — Zoologica Scripta, **, ***–***. We investigated the phylogenetic relationships among monogenean parasites of the Chaetodontidae (butterflyfishes) from the Indo-West Pacific Ocean. Molecular phylogenies of selected taxa within the Dactylogyridae, including the ancyrocephaline parasites of butterflyfishes, based on two nuclear and one mitochondrial gene fragments (complete 18S rDNA, partial 28S rDNA (D1-D3), and partial 16S rDNA) were reconstructed using parsimony, maximum likelihood and Bayesian inference methods. Our results show the non-monophyletic nature of the monogenean fauna of butterflyfishes. The group is divided into two independent lineages. The first clade contains species of the genera Aliatrema and Euryhaliotrematoides, which parasitize Chaetodontidae exclusively. The second contains species of Haliotrema, a generalist group of parasites. The positions of several other species of the Ancyrocephalinae, including freshwater species, at the base of the two clades, provide strong evidence that the monogenean fauna did not result from a single colonization event, but rather that they have colonized their butterflyfish hosts independently at least twice. [ABSTRACT FROM AUTHOR]

Published
2005
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12. RNA-mediated gene suppression and in vitro culture in Hymenolepis microstoma.

Author

Pouchkina-Stantcheva, Natalia N., Cunningham, Lucas J., Hrčkova, Gabriela, and Olson, Peter D.

Subjects
*HYMENOLEPIS, *RNA interference, *IN vitro studies, *TRANSCRIPTION factors, *HOMEOBOX genes, *GENETIC regulation, *LIFE cycles (Biology)
Abstract

Highlights: [•] Methods for RNA interference (RNAi) and in vitro culture in Hymenolepis are tested. [•] Up to 80% suppression of a Hox transcription factor is demonstrated. [•] Efficiency of double-stranded/short-interfering RNA delivery is stage-dependent. [•] Gene regulation via RNAi is active throughout the life cycle. [•] At least two distinct RNAi pathways appear to operate. [Copyright &y& Elsevier]

Published
2013
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13. Substitution saturation and nuclear paralogs of commonly employed phylogenetic markers in the Caryophyllidea, an unusual group of non-segmented tapeworms (Platyhelminthes)

Author

Brabec, Jan, Scholz, Tomáš, Králová-Hromadová, Ivica, Bazsalovicsová, Eva, and Olson, Peter D.

Subjects
*PHYLOGENY, *GENETIC markers, *CARYOPHYLLIDEA, *PLATYHELMINTHES, *TAPEWORMS, *MITOCHONDRIAL DNA
Abstract

Abstract: Caryophyllidean cestodes (Platyhelminthes) represent an unusual group of tapeworms lacking serially repeated body parts that potentially diverged from the common ancestor of the Eucestoda prior to the evolution of segmentation. Here we evaluate the utility of two nuclear and two mitochondrial molecular markers (ssrDNA and lsrDNA, nad3 and cox1) for use in circumscribing generic boundaries and estimating interrelationships in the group. We show that these commonly employed markers do not contain sufficient signal to infer well-supported phylogenetic estimates due to substitution saturation. Moreover, we detected multiple trnK+ nad3+ trnS+ trnW+ cox1 haplotypes within individuals, indicating a history of gene exchange between the mitochondrial and nuclear genomes. The presence of such nuclear paralogs (i.e. numts), to our knowledge described here in cestodes for the first time, together with the results of phylogenetic, saturation and split-decomposition analyses all suggest that finding informative markers for estimating caryophyllidean evolution is unusually problematic in comparison to other major lineages of tapeworms. [Copyright &y& Elsevier]

Published
2012
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