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Louro M, Kuzmina TA, Bredtmann CM, Diekmann I, de Carvalho LMM, von Samson-Himmelstjerna G, Krücken J. Genetic variability, cryptic species and phylogenetic relationship of six cyathostomin species based on mitochondrial and nuclear sequences. Sci Rep 2021; 11:8245. [PMID: 33859247 PMCID: PMC8050097 DOI: 10.1038/s41598-021-87500-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/30/2021] [Indexed: 11/23/2022] Open
Abstract
Cyathostomins are important intestinal nematode parasites of equines and include 50 accepted species. Their taxonomy has been frequently revised and the presence of cryptic species suggested. Furthermore, usually molecular- and morphology-based phylogenetic analyses give divergent results. In this study, the nucleotide sequences of the nuclear second internal transcribed spacer (ITS-2) and the mitochondrial partial cytochrome c oxidase subunit I (COI) were determined for adults of six cyathostomin species (Coronocyclus coronatus, Coronocyclus labiatus, Cylicocyclus nassatus, Cylicostephanus calicatus, Cylicostephanus longibursatus, Cylicostephanus minutus) collected from different equine species within two geographic regions. Maximum likelihood trees were calculated for ITS-2, COI, and concatenated data. No obvious differentiation was observed between geographic regions or equine host species. As previously reported, Coronocyclus coronatus and Cylicostephanus calicatus revealed a close relationship. Cryptic species were detected in Cylicostephanus minutus and Cylicostephanus calicatus. Cylicocyclus nassatus and Coronocyclus labiatus showed diverse mitochondrial and nuclear haplotypes occurring in different combinations, while Cylicostephanus longibursatus was comparatively homogenous. In conclusion, a combined analysis of nuclear and mitochondrial haplotypes improved resolution of the phylogeny and should be applied to the remaining cyathostomin species and across additional equine host species and geographic regions.
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Affiliation(s)
- Mariana Louro
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | - Tetiana A Kuzmina
- I. I. Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Christina M Bredtmann
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Irina Diekmann
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Luís M Madeira de Carvalho
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | - Georg von Samson-Himmelstjerna
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
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Bredtmann CM, Krücken J, Kuzmina T, Louro M, Madeira de Carvalho LM, von Samson-Himmelstjerna G. Nuclear and mitochondrial marker sequences reveal close relationship between Coronocyclus coronatus and a potential Cylicostephanus calicatus cryptic species complex. INFECTION GENETICS AND EVOLUTION 2019; 75:103956. [PMID: 31299325 DOI: 10.1016/j.meegid.2019.103956] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 06/28/2019] [Accepted: 07/06/2019] [Indexed: 11/29/2022]
Abstract
The Cyathostominae (Nematoda, Strongyloidea) parasitising equines represent a diverse group currently including 50 species. However, their taxonomy has been repeatedly revised and occasionally the presence of cryptic genospecies was suggested. Moreover, molecular- and morphology-based phylogenetic analyses give divergent results. For instance, molecular data have suggested close relationship between Coronocyclus coronatus and Cylicostephanus calicatus, although morphology-based taxonomy places them in different genera. Here, nuclear (internal transcribed spacer 2, ITS-2) and mitochondrial (cytochrome oxidase I, COI) sequences were obtained from the same individual, morphologically identified worms. In both morphospecies, two ITS-2 sequences types were observed: In Cor. coronatus, a small PCR product of 278 bp (nuclear haplotype group nHGBco) was always present but often in combination with a larger 369-370 bp fragment (nHGAco). In Cys. calicatus, either a large 370 bp product (nHGAca) or a short 281 bp amplicon (nHGBca) were found, but never both. Sequence identity between morphospecies was up to 100%. The smaller differed from the larger fragments by deletion of the region 110-198 in Cor. coronatus and 112-203 in Cys. calicatus. In COI, three and five mitochondrial haplotype groups (HGs), mtHG1co-mtHG3co and mtHG1ca-mtHG5ca were identified for Cor. coronatus and Cys. calicatus, respectively. In Cor. coronatus, there was no particular association of mtHG with nuclear genotypes (only nHGBco vs. both nHGBco plus nHGAco). In Cys. calicatus the nHGAca was always associated with the mtHG1ca, mtHG2ca or mtHG5ca whereas nHGBca was exclusively associated with mtHG3ca or mtHG4ca. Despite up to 100% identity in the nHGs, no mixing of mtHGs was observed between both species. Clear separation of certain nHGs with particular mtHGs in Cys. calicatus, despite the fact that the same host individuals were infected with both groups simultaneously, suggests presence of two non-interbreeding genospecies within Cys. calicatus, which needs further confirmation using additional samples from diverse geographical origins.
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Affiliation(s)
- Christina M Bredtmann
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Germany
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Germany.
| | - Tetiana Kuzmina
- Department of Parasitology, I. I. Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, Kiev, Ukraine
| | - Mariana Louro
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Germany; CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Portugal
| | - Luís M Madeira de Carvalho
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Portugal
| | - Georg von Samson-Himmelstjerna
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Germany
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Saeed MA, Beveridge I, Abbas G, Beasley A, Bauquier J, Wilkes E, Jacobson C, Hughes KJ, El-Hage C, O'Handley R, Hurley J, Cudmore L, Carrigan P, Walter L, Tennent-Brown B, Nielsen MK, Jabbar A. Systematic review of gastrointestinal nematodes of horses from Australia. Parasit Vectors 2019; 12:188. [PMID: 31036059 PMCID: PMC6489199 DOI: 10.1186/s13071-019-3445-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 04/12/2019] [Indexed: 12/24/2022] Open
Abstract
Background Equine gastrointestinal nematodes (GINs) have been the subject of intermittent studies in Australia over the past few decades. However, comprehensive information on the epidemiology of equine GINs, the efficacy of available anthelmintic drugs and the prevalence of anthelmintic resistance (AR) in Australasia is lacking. Herein, we have systematically reviewed existing knowledge on the horse GINs recorded in Australia, and main aspects of their pathogeneses, epidemiology, diagnoses, treatment and control. Methods Six electronic databases were searched for publications on GINs of Australian horses that met our inclusion criteria for the systematic review. Subsets of publications were subjected to review epidemiology, diagnoses, pathogeneses, treatment and control of GINs of horses from Australia. Results A total of 51 articles published between 1950 to 2018 were included. The main GINs reported in Australian horses were cyathostomins (at least 28 species), Draschia megastoma, Habronema muscae, H. majus, Oxyuris equi, Parascaris equorum, Strongyloides westeri and Trichostrongylus axei across different climatic regions of Queensland, New South Wales, Victoria, and Western Australia. Nematodes are diagnosed based on the traditional McMaster egg counting technique, though molecular markers to characterise common GINs of equines were characterised in 1990s. The use of anthelmintic drugs remains the most widely-used strategy for controlling equine GIN parasites in Australia; however, the threshold of faecal egg count that should trigger treatment in horses, remains controversial. Furthermore, anthelmintic resistance within GIN population of horses is becoming a common problem in Australia. Conclusions Although GINs infecting Australian horses have been the subject of occasional studies over the past few decades, the effective control of GIN infections is hampered by a generalised lack of knowledge in various disciplines of equine parasitology. Therefore, coordinated and focused research is required to fill our knowledge gaps in these areas to maximise equine health and minimise economic losses associated with the parasitic infections in Australia. Electronic supplementary material The online version of this article (10.1186/s13071-019-3445-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Muhammad A Saeed
- Melbourne Veterinary School, The University of Melbourne, Werribee, VIC, Australia
| | - Ian Beveridge
- Melbourne Veterinary School, The University of Melbourne, Werribee, VIC, Australia
| | - Ghazanfar Abbas
- Melbourne Veterinary School, The University of Melbourne, Werribee, VIC, Australia
| | - Anne Beasley
- School of Veterinary Science, University of Queensland, Gatton, QLD, Australia
| | - Jenni Bauquier
- Melbourne Veterinary School, The University of Melbourne, Werribee, VIC, Australia
| | - Edwina Wilkes
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Caroline Jacobson
- School of Veterinary & Life Sciences, Murdoch University, Murdoch, WA, Australia
| | - Kris J Hughes
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Charles El-Hage
- Melbourne Veterinary School, The University of Melbourne, Werribee, VIC, Australia
| | - Ryan O'Handley
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA, Australia
| | | | | | | | - Lisa Walter
- Boehringer Ingelheim Animal Health Australia Pty. Ltd, North Ryde, NSW, Australia
| | - Brett Tennent-Brown
- Melbourne Veterinary School, The University of Melbourne, Werribee, VIC, Australia
| | - Martin K Nielsen
- M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, USA
| | - Abdul Jabbar
- Melbourne Veterinary School, The University of Melbourne, Werribee, VIC, Australia.
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Ullrich B, Reinhold K, Niehuis O, Misof B. Secondary structure and phylogenetic analysis of the internal transcribed spacers 1 and 2 of bush crickets (Orthoptera: Tettigoniidae: Barbitistini). J ZOOL SYST EVOL RES 2009. [DOI: 10.1111/j.1439-0469.2009.00553.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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5
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Fazenda IP, Beveridge I, Chilton NB, Jex AR, Pangasa A, Campbell BE, Huby-Chilton F, Carvalho LM, Gasser RB. Analysis of genetic variation in Globocephaloides populations from macropodid marsupials using a mutation scanning-based approach. Electrophoresis 2009; 30:2758-64. [PMID: 19650048 DOI: 10.1002/elps.200900306] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Three species of Globocephaloides, parasitic nematodes occurring in macropodid marsupials in different areas of Australia, were characterized by the sequences of the first and second internal transcribed spacers (ITS-1 and ITS-2) of nuclear ribosomal DNA. Samples were subjected to PCR-coupled SSCP analysis and targeted sequencing, in order to assess genetic variation within and among individuals from different host species. Both SSCP and sequence data supported the current classification of morphospecies. Contrary to a previous hypothesis that cryptic species exist within the Globocephaloides trifidospicularis "complex", no or minor (0.2%) variation was detected among individuals from different hosts or geographical origins. Within G. macropodis populations, there was a consistent difference in both the ITS-1 (5.2%) and ITS-2 (7.1%) sequences between individuals derived from Macropus agilis and those from Macropus dorsalis. Although the results suggested that G. macropodis from each host species represented sibling species, future morphological study of individuals representing each G. macropodis genotype is warranted to provide further support for this hypothesis. (Nucleotide sequence data have been deposited in the GenBank database under accession nos. GQ131400-GQ131409.).
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Affiliation(s)
- Inês P Fazenda
- Department of Veterinary Science, The University of Melbourne, Victoria, Australia
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6
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Comparative analysis of sequences and secondary structures of the rRNA internal transcribed spacer 2 (ITS2) in pollen beetles of the subfamily Meligethinae (Coleoptera, Nitidulidae): potential use of slippage-derived sequences in molecular systematics. Mol Phylogenet Evol 2008; 51:215-26. [PMID: 19059352 DOI: 10.1016/j.ympev.2008.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 11/05/2008] [Accepted: 11/06/2008] [Indexed: 11/21/2022]
Abstract
A comparative analysis of ITS2 sequences and secondary structures in 89 species of pollen beetles of the subfamily Meligethinae (Coleoptera, Nitidulidae) was performed. The ITS2 folding pattern was highly conserved and comparable with the general model proposed for eukaryotes. Simple sequence repeats (SSRs) were responsible for most of the observed nucleotide variability (approximately 1-3%) and length variation (359-459bp). When plotted on secondary structures, SSRs mapped in expansion segments positioned at the apices of three ITS2 helices ('A', 'B' and 'D1') and appeared to have evolved under mechanisms of compensatory slippage. Homologies among SSRs nucleotides could not be unambiguously assigned, and thus were not useful to resolve phylogeny. However, slippage-derived motifs provided some preliminary genetic support for newly proposed taxonomic arrangements of several genera and subgenera of Meligethinae, corroborating existing morphological and ecological datasets.
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Toward practical, DNA-based diagnostic methods for parasitic nematodes of livestock — Bionomic and biotechnological implications. Biotechnol Adv 2008; 26:325-34. [DOI: 10.1016/j.biotechadv.2008.03.003] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Revised: 03/06/2008] [Accepted: 03/14/2008] [Indexed: 11/22/2022]
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Abstract
For evolutionary comparisons, phylogenetics and evaluation of potential interbreeding taxa of a species, various loci have served for animals and plants and protistans. One [second internal transcribed spacer (ITS2) of the nuclear ribosomal DNA] is highly suitable for all. Its sequence is species specific. It has already been used extensively and very successfully for plants and some protistans, and a few animals (where historically, the mitochondrial genes have dominated species studies). Despite initial impressions that ITS2 is too variable, it has proven to provide useful biological information at higher taxonomic levels, even across all eukaryotes, thanks to the conserved aspects of its transcript secondary structure. The review of all eukaryote groups reveals that ITS2 is expandable, but always retains in its RNA transcript a common core structure of two helices with hallmark characteristics important for ribosomal RNA processing. This aspect of its RNA transcript secondary structure can rescue difficult alignment problems, making the ITS2 a more powerful tool for phylogenetics. Equally important, the recognition of eukaryote-wide homology regions provides extensive and detailed information to test experimental studies of ribosomal rRNA processing.
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Affiliation(s)
- Annette W Coleman
- Division of Biology and Medicine, Brown University, Providence, RI 02912, USA.
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Zhang L, Hu M, Chilton NB, Huby-Chilton F, Beveridge I, Gasser RB. Nucleotide alterations in the D3 domain of the large subunit of ribosomal DNA among 21 species of equine strongyle. Mol Cell Probes 2007; 21:111-5. [PMID: 17097265 DOI: 10.1016/j.mcp.2006.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2006] [Revised: 08/30/2006] [Accepted: 08/31/2006] [Indexed: 10/24/2022]
Abstract
The expansion segments or divergent (D) domains in the large subunit (LSU) of the ribosomal DNA have been suggested as genetic markers for taxonomic and/or phylogenetic studies of parasites. In the present study, we assessed the degree of sequence variation in the D3 domain and flanking core regions of the LSU for 21 species of equine strongyles (Strongylida: Strongylidae) and determined which positions in the secondary structure of the LSU were associated with the nucleotide alterations. No intraspecific sequence variation was detected in 17 species, for which multiple individual worms were available. Mutations in sequence among species were detected at 19 nucleotide positions, most of which were located in the D3 domain. Fifteen alterations were transitions, three were transversions and one represented a site of multiple mutations. In relation to the secondary structure element of D3, 26% of these mutations were located in unpaired regions (i.e., end of loops, or in bulges of helices) and thus did not appear to alter the pairing arrangement in the helices of the secondary structure. Many of the other mutations represented partial or complete compensatory base pair changes. The magnitude of interspecific nucleotide variation in the D3 domain (0-4%) was considerably less than that recorded for some other nematode groups (enoplids and thelastomatoids), indicating that this region alone is of limited value for taxonomic and phylogenetic studies for strongyles of equids but is interesting in relation to the evolution of ribosomal DNA.
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Affiliation(s)
- Luping Zhang
- Department of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia
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10
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Wang S, Bao Z, Li N, Zhang L, Hu J. Analysis of the secondary structure of ITS1 in Pectinidae: implications for phylogenetic reconstruction and structural evolution. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2007; 9:231-42. [PMID: 17286216 DOI: 10.1007/s10126-006-6113-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2006] [Revised: 10/09/2006] [Indexed: 05/13/2023]
Abstract
It is at present difficult to accurately position gaps in sequence alignment and to determine substructural homology in structure alignment when reconstructing phylogenies based on highly divergent sequences. Therefore, we have developed a new strategy for inferring phylogenies based on highly divergent sequences. In this new strategy, the whole secondary structure presented as a string in bracket notation is used as phylogenetic characters to infer phylogenetic relationships. It is no longer necessary to decompose the secondary structure into homologous substructural components. In this study, reliable phylogenetic relationships of eight species in Pectinidae were inferred from the structure alignment, but not from sequence alignment, even with the aid of structural information. The results suggest that this new strategy should be useful for inferring phylogenetic relationships based on highly divergent sequences. Moreover, the structural evolution of ITS1 in Pectinidae was also investigated. The whole ITS1 structure could be divided into four structural domains. Compensatory changes were found in all four structural domains. Structural motifs in these domains were identified further. These motifs, especially those in D2 and D3, may have important functions in the maturation of rRNAs.
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Affiliation(s)
- Shi Wang
- Laboratory of Marine Genetics and Breeding, Division of Life Science and Technology, Ocean University of China, Qingdao, 266003, People's Republic of China
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11
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Hypsa V. Parasite histories and novel phylogenetic tools: Alternative approaches to inferring parasite evolution from molecular markers. Int J Parasitol 2006; 36:141-55. [PMID: 16387305 DOI: 10.1016/j.ijpara.2005.10.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Revised: 10/19/2005] [Accepted: 10/28/2005] [Indexed: 10/25/2022]
Abstract
Parasitological research is often contingent on the knowledge of the phylogeny/genealogy of the studied group. Although molecular phylogenetics has proved to be a powerful tool in such investigations, its application in the traditional fashion, based on a tree inference from the primary nucleotide sequences may, in many cases, be insufficient or even improper. These limitations are due to a number of factors, such as a scarcity/ambiguity of phylogenetic information in the sequences, an intricacy of gene relationships at low phylogenetic levels, or a lack of criteria when deciding among several competing coevolutionary scenarios. With respect to the importance of a precise and reliable phylogenetic background in many biological studies, attempts are being made to extend molecular phylogenetics with a variety of new data sources and methodologies. In this review, selected approaches potentially applicable to parasitological research are presented and their advantages as well as drawbacks are discussed. These issues include the usage of idiosyncratic markers (unique features with presumably low probability of homoplasy), such as insertion of mobile elements, gene rearrangements and secondary structure features; the problem of ancestral polymorphism and reticulate relationships at low phylogenetic levels; and the utility of a molecular clock to facilitate discrimination among alternative scenarios in host-parasite coevolution.
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Affiliation(s)
- Václav Hypsa
- Faculty of Biological Sciences, University of South Bohemia, and Institute of Parasitology, Academy of Sciences of the Czech Republic, Branisovská 31, 37005 Ceské Budejovice, Czech Republic.
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12
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Chilton NB. The use of nuclear ribosomal DNA markers for the identification of bursate nematodes (order Strongylida) and for the diagnosis of infections. Anim Health Res Rev 2005; 5:173-87. [PMID: 15984323 DOI: 10.1079/ahr200497] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Many bursate nematodes are of major importance to animal health. Animals are often parasitized by multiple species that differ in their prevalence, relative abundance and/or pathogenicity. Implementation of effective management strategies for these parasites requires reliable methods for their detection in hosts, identification to the species level and measurement of intensity of infection. One major problem is the difficulty of accurately identifying and distinguishing many species of bursate nematode because of the remarkable morphological similarity of their eggs and larvae. The inability to identify, with confidence, individual nematodes (irrespective of their life-cycle stage) to the species level by morphological methods has often led to a search for species-specific genetic markers. Studies over the past 15 years have shown that sequences of the internal transcribed spacers of ribosomal DNA provide useful genetic markers, providing the basis for the development of PCR-based diagnostic tools. Such molecular methods represent powerful tools for studying the systematics, epidemiology and ecology of bursate nematodes and, importantly, for the specific diagnosis of infections in animals and humans, thus contributing to improved control and prevention strategies for these parasites.
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Affiliation(s)
- Neil B Chilton
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.
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Gasser RB, Hung GC, Chilton NB, Beveridge I. Advances in developing molecular-diagnostic tools for strongyloid nematodes of equids: fundamental and applied implications. Mol Cell Probes 2004; 18:3-16. [PMID: 15036364 DOI: 10.1016/j.mcp.2003.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2003] [Accepted: 10/17/2003] [Indexed: 11/24/2022]
Abstract
Infections of equids with parasitic nematodes of the order Strongylida (subfamilies Strongylinae and Cyathostominae) are of major veterinary importance. In last decades, the widespread use of drugs against these parasites has led to problems of resistance within the Cyathostominae, and to an increase in their prevalence and intensity of infection. Novel control strategies, based on improved knowledge of parasite biology and epidemiology, have thus become important. However, there are substantial limitations in the understanding of fundamental biological and systematic aspects of these parasites, which have been due largely to limitations in their specific identification and diagnosis using traditional, morphological approaches. Recently, there has been progress in the development of DNA-based approaches for the specific identification of strongyloids of equids for systematic studies and disease diagnosis. The present article briefly reviews information on the classification, biology, pathogenesis, epidemiology of equine strongyloids and the diagnosis of infections, highlights knowledge gaps in these areas, describes recent advances in the use of molecular techniques for the genetic characterisation, specific identification and differentiation of strongyloids of equids as a basis for fundamental investigations of the systematics, population biology and ecology.
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Affiliation(s)
- Robin B Gasser
- Department of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia.
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14
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Carreno RA, Nadler SA. Phylogenetic analysis of the Metastrongyloidea (Nematoda: Strongylida) inferred from ribosomal RNA gene sequences. J Parasitol 2003; 89:965-73. [PMID: 14627145 DOI: 10.1645/ge-76r] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Phylogenetic relationships among nematodes of the strongylid superfamily Metastrongyloidea were analyzed using partial sequences from the large-subunit ribosomal RNA (LSU rRNA) and small-subunit ribosomal RNA (SSU rRNA) genes. Regions of nuclear ribosomal DNA (rDNA) were amplified by polymerase chain reaction, directly sequenced, aligned, and phylogenies inferred using maximum parsimony. Phylogenetic hypotheses inferred from the SSU rRNA gene supported the monophyly of representative taxa from each of the 7 currently accepted metastrongyloid families. Metastrongyloid taxa formed the sister group to representative trichostrongyloid sequences based on SSU data. Sequences from either the SSU or LSU RNA regions alone provided poor resolution for relationships within the Metastrongyloidea. However, a combined analysis using sequences from all rDNA regions yielded 3 equally parsimonious trees that represented the abursate Filaroididae as polyphyletic, Parafilaroides decorus as the sister species to the monophyletic Pseudaliidae, and a sister group relationship between Oslerus osleri and Metastrongylus salmi. Relationships among 3 members of the Crenosomatidae, and 1 representative of the Skrjabingylidae (Skrjabingylus chitwoodorum) were not resolved by these combined data. However, members of both these groups were consistently resolved as the sister group to the other metastrongyloid families. These relationships are inconsistent with traditional classifications of the Metastrongyloidea and existing hypotheses for their evolution.
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Affiliation(s)
- Ramon A Carreno
- Department of Nematology, University of California-Davis, Davis, California 95616, USA.
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15
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Huby-Chilton F, Beveridge I, Gasser RB, Chilton NB. Redescription of Zoniolaimus mawsonae Beveridge, 1983 (Nematoda: Strongyloidea) and the description of Z. latebrosus n. sp. from the red kangaroo Macropus rufus (Marsupialia: Macropodidae) based on morphological and molecular data. Syst Parasitol 2002; 51:135-47. [PMID: 11912339 DOI: 10.1023/a:1014002917647] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study shows that the description of Z. mawsonae given by Beveridge (1983) represented a composite of two species. Hence, Z. mawsonae Beveridge, 1983 is re-described and a new species, Z. latebrosus, is described. Males of the two species differ in the lengths of their spicules (0.94-1.23 mm in Z. mawsonae compared with 1.53-1.95 mm in Z. latebrosus) and in several characteristics of the bursa and genital cone. Females of the two species can be identified based on the shape of the posterior end of the body, that of Z. mawsonae being markedly swollen. Molecular data, obtained from single strand conformation polymorphism (SSCP) analysis and DNA sequencing of the second internal transcribed spacer of ribosomal DNA, provided additional support for the separation of the two species.
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Affiliation(s)
- Florence Huby-Chilton
- Department of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia
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Chilton NB, Huby-Chilton F, Gasser RB, Beveridge I. Review of Papillostrongylus Johnston & Mawson, 1939 (Nematoda: Strongyloidea) from wallabies and kangaroos (Marsupialia: Macropodidae) using morphological and molecular techniques, with the description of P. barbatus n. sp. Syst Parasitol 2002; 51:81-93. [PMID: 11912337 DOI: 10.1023/a:1014062830560] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The strongyloid nematode genus Papillostrongylus Johnston & Mawson, 1939, from kangaroos and wallabies, is reviewed using morphological and molecular methods. P. labiatus Johnston & Mawson, 1939 is re-described from material from the type-host, the black-striped wallaby Macropus dorsalis, from eastern Queensland, Australia, in which it is a relatively common parasite. Additional records from M. parryi and Thylogale thetis are confirmed and considered to represent examples of host-switching. A geographically disjunct population of the nematode species occurs in M. bernardus and Petrogale brachyotis in Arnhem Land, Northern Territory, but assessment of its status requires additional material. Nematodes from M. rufus, M. giganteus, M. fuliginosus and M. robustus from inland regions of Australia, formerly attributed to P. labiatus, are here assigned to a new species, P. barbatus, distinguished by the presence of an external leaf-crown, larger size, by greater spicule length in the male and by a sinuous vagina in the female. Additional hosts of P. barbatus n. sp. are Petrogale assimilis and Pet. lateralis purpureicollis. Sequence analyses of the second internal transcribed spacer of ribosomal DNA (ITS-2) also showed that P. barbatus n. sp. differed at 40 (16.7%) of the 240 alignment positions when compared with P. labiatus. Most of these interspecific sequence differences occurred in loops or bulges of the predicted precursor rRNA secondary structure, or represented partial or total compenstory base pair changes in stems.
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Affiliation(s)
- N B Chilton
- Department of Veterinary Science, University of Melbourne, Parkville, Victoria, 3052, Australia
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Gasser RB, Chilton NB. Applications of single-strand conformation polymorphism (SSCP) to taxonomy, diagnosis, population genetics and molecular evolution of parasitic nematodes. Vet Parasitol 2001; 101:201-13. [PMID: 11707297 DOI: 10.1016/s0304-4017(01)00567-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The analysis of genetic variation in parasitic nematodes has important implications for studying aspects of taxonomy, diagnosis, population genetics, drug resistance and molecular evolution. This article highlights some applications of PCR-based single-strand conformation polymorphism (SSCP) for the analysis of sequence variation in individual parasites (and their populations) to address some of these areas. It also describes the principles and advantages of SSCP, and provides some examples for future applications in parasitology.
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Affiliation(s)
- R B Gasser
- Department of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia.
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Gouÿ de Bellocq J, Ferté H, Depaquit J, Justine JL, Tillier A, Durette-Desset MC. Phylogeny of the Trichostrongylina (Nematoda) inferred from 28S rDNA sequences. Mol Phylogenet Evol 2001; 19:430-42. [PMID: 11399151 DOI: 10.1006/mpev.2001.0925] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We produced a molecular phylogeny of species within the order Strongylida (bursate nematodes) using the D1 and D2 domains of 28S rDNA, with 23 new sequences for each domain. A first analysis using Caenorhabditis elegans as an outgroup produced a tree with low resolution in which three taxa (Dictyocaulus filaria, Dictyocaulus noerneri, and Metastrongylus pudendotectus) showed highly divergent sequences. In a second analysis, these three species and C. elegans were removed and an Ancylostomatina, Bunostomum trigonocephalum, was chosen (on the basis of previous morphological analyses) as the outgroup for an analysis of the phylogenetic relationships between and within the Strongylina (strongyles) and Trichostrongylina (trichostrongyles). A very robust tree was obtained. The Trichostrongylina were monophyletic, but the Strongylina were paraphyletic, though this requires confirmation. Within the Trichostrongylina, the three superfamilies defined from morphological characters are confirmed, with the Trichostrongyloidea sister group to a clade including the Molineoidea and Heligmosomoidea. Within the Trichostrongyloidea, the Cooperiidae, Trichostrongylidae, and Haemonchidae were polytomous, the Haemonchinae were monophyletic, but the Ostertagiinae were paraphyletic. The sister-group relationships between Molineoidea and Heligmosomoidea were unsuspected from previous morphological analysis. No unequivocal morphological synapomorphy could be found for the grouping Molineoidea + Heligmosomoidea, but none was found which contradicted it.
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Affiliation(s)
- J Gouÿ de Bellocq
- Laboratoire de Biologie Parasitaire, Protistologie, et Helminthologie, Muséum National d'Histoire Naturelle, 61 Rue Buffon, Paris Cedex 05, 75231, France
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Huby-Chilton F, Beveridge I, Gasser RB, Chilton NB. Single-strand conformation polymorphism analysis of genetic variation in Labiostrongylus longispicularis from kangaroos. Electrophoresis 2001; 22:1925-9. [PMID: 11465490 DOI: 10.1002/1522-2683(200106)22:10<1925::aid-elps1925>3.0.co;2-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Single-strand conformation polymorphism (SSCP) analysis was employed to screen for sequence heterogeneity in the second internal transcribed spacer (ITS-2) of ribosomal (r) DNA of Labiostrongylus longispicularis, a parasitic strongylid nematode occuring in some species of kangaroo in different geographical regions of Australia. The results showed that most of the nematodes screened had different SSCP profiles, which were subsequently shown to correspond to polymorphisms and/or an indel in the ITS-2 sequence. These variable sites related mainly to unpaired regions of the predicted secondary structure of the precursor rRNA molecule. SSCP profiles could be used to distinguish L. longispicularis in Macropus robustus robustus (New South Wales) from L. longispicularis in Macropus robustus erubescens and Macropus rufus (South Australia). This difference corresponded to a transversional change in the ITS-2 sequence at alignment position 82. The study demonstrated clearly the effectiveness of SSCP analysis for future large-scale population genetic studies of L. longispicularis in order to test the hypothesis that L. longispicularis from different geographical regions represents multiple sibling species.
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Affiliation(s)
- F Huby-Chilton
- Department of Veterinary Science, The University of Melbourne, Werribee, Victoria, Australia.
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20
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Chilton NB, Newton LA, Beveridge I, Gasser RB. Evolutionary relationships of trichostrongyloid nematodes (Strongylida) inferred from ribosomal DNA sequence data. Mol Phylogenet Evol 2001; 19:367-86. [PMID: 11399147 DOI: 10.1006/mpev.2001.0938] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The evolutionary relationships of 21 species of trichostrongyloid nematodes were determined by use of sequence data of the second internal transcribed spacer of the ribosomal DNA aligned according to secondary structure information. Irrespective of the method of analysis used, the topologies of the phylogenetic trees derived from the molecular data differed with respect to all four hypotheses proposed previously for the evolutionary relationships of the different subfamilies within the Trichostrongylidae based on morphological data. Thus, the molecular data set did not resolve the conflict between the four previous proposals for the subfamilial relationships. Nonetheless, all trees derived from the molecular data showed strong support for the exclusion of the genera Filarinema and Amidostomum from the clade containing the species within the family Trichostrongylidae. This represents a major difference from the most recent proposal of the systematics of the Trichostrongyloidea in which these two genera were included within the Trichostrongylidae. Therefore, the molecular data support an earlier systematic framework in which Filarinema and Amidostomum were considered to be sister groups of the Trichostrongyloidea.
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MESH Headings
- Animals
- Base Sequence
- DNA, Helminth/chemistry
- DNA, Helminth/genetics
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- DNA, Ribosomal Spacer/genetics
- Evolution, Molecular
- Molecular Sequence Data
- Nucleic Acid Conformation
- Phylogeny
- RNA, Ribosomal/chemistry
- RNA, Ribosomal/genetics
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- Trichostrongyloidea/classification
- Trichostrongyloidea/genetics
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Affiliation(s)
- N B Chilton
- Department of Veterinary Science, University of Melbourne, 250 Princes Highway, Werribee, Victoria, 3030, Australia
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Gasser RB, Zhu X, Beveridge I, Chilton N. Mutation scanning analysis of sequence heterogeneity in the second internal transcribed spacer (rDNA) within some members of theHypodontus macropi (Nematoda: Strongyloidea) complex. Electrophoresis 2001; 22:1076-85. [PMID: 11358128 DOI: 10.1002/1522-2683()22:6<1076::aid-elps1076>3.0.co;2-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Single-strand conformation polymorphism analysis was employed to investigate sequence variation in the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA within and among individuals representing three operational taxonomic units (OTUs) of Hypodontus macropi from different species of Australian macropodid marsupials. Of the 96 nematodes analysed, totals of 3 (OTU1 from Petrogale persephone), 10 (OTU2 from Macropus robustus) and 7 (OTU9 from Macropus rufus) representative individuals were selected for DNA sequencing to characterise and estimate the magnitude of nucleotide variation in the ITS-2. While no unequivocal nucleotide difference in the ITS-2 was detectable within OTU1, most sequence variation (3/44.7%) detected within OTU2 and OTU9 was related chiefly to dinucleotide (CA, TA, or a combination of both) differences. This microsatellite variability in some H. macropi OTUs suggests that the ITS-2 rDNA may be subjected to slippage events during DNA replication, resulting in short dinucleotide repeat tracts being dispersed throughout the ITS-2 lineages, or possibly transposition and/or crossing-over events. Nucleotide variation in the ITS-2 of individual OTUs was related to the proposed secondary structure for the precursor ribosomal RNAs. Most of the sequence heterogeneity or polymorphism within OTU2 and OTU9 occurred in loops or bulges of the predicted secondary structure, which appear not to be under functional constraint. The findings of this study have implications for investigating speciation events and population differentiation in nematodes at the molecular level.
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Affiliation(s)
- R B Gasser
- Department of Veterinary Science, The University of Melbourne, Werribee, Victoria, Australia.
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Gasser RB, Newton SE. Genomic and genetic research on bursate nematodes: significance, implications and prospects. Int J Parasitol 2000; 30:509-34. [PMID: 10731573 DOI: 10.1016/s0020-7519(00)00021-7] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Molecular genetic research on parasitic nematodes (order Strongylida) is of major significance for many fundamental and applied areas of medical and veterinary parasitology. The advent of gene technology has led to some progress for this group of nematodes, particularly in studying parasite systematics, drug resistance and population genetics, and in the development of diagnostic assays and the characterisation of potential vaccine and drug targets. This paper gives an account of the molecular biology and genetics of strongylid nematodes, mainly of veterinary socio-economic importance, indicates the implications of such research and gives a perspective on genome research for this important parasite group, in light of recent technological advances and knowledge of the genomes of other metazoan organisms.
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Affiliation(s)
- R B Gasser
- Department of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria, Australia.
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