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Vodiasova EA, Chelebieva ES, Shikhat OV, Atopkin DM, Dmitrieva EV. Molecular-genetic approaches to species identification of platyhelminthes of the genus <i>Ligophorus</i> (Monogenea) parasitising flathead mullet. Vavilovskii Zhurnal Genet Selektsii 2022; 26:290-297. [PMID: 35774361 PMCID: PMC9167819 DOI: 10.18699/vjgb-22-36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 01/06/2022] [Accepted: 01/18/2021] [Indexed: 12/02/2022] Open
Abstract
Mugil cephalus L., 1758 (flathead mullet) is a valuable commercial fish and a promising object of artificial breeding in the Black Sea and the Sea of Azov, and the study of its parasite fauna is important for fishery and mariculture. Monogeneans of the genus Ligophorus are common ectoparasites dwelling on the gills of mullets. Two representatives of this genus parasitise flathead mullet in the Azov-Black Sea region, namely Ligophorus mediterraneus Sarabeev, Balbuena et Euzet, 2005 and Ligophorus cephali Rubtsova, Balbuena, Sarabeev, Blasco-
Costa et Euzet, 2006. Morphological identification of these species requires spending much time and a high level
of experience in monogenean taxonomy. For quick and correct species identification of these parasites, we have
developed a genotyping approach based on the polymerase chain reaction of allele-specific gene sites for various
Monogenea species. A fragment of the 28S ribosomal gene, which includes conserved and variable sites, was
chosen as a genetic marker. Three approaches were used as follows: amplified fragment length analysis, allelespecific
PCR with endpoint detection and allele-specific real-time PCR using SYBR Green intercalating dye. The
first approach was by obtaining PCR products of different lengths that were specific either to L. mediterraneus or
to L. cephali. This approach was implemented due to the presence of several variable sites located at a distance
from each other. The PCR mixture contained three primers: one forward and two reverse. The forward primer
was complementary to the conserved site, which did not differ between species. Reverse primers were speciesspecific
and, for each species, they were complementary to different DNA regions located 100 bp apart. As a result,
L. mediterraneus was characterized by shorter amplicons than L. cephali. For the second and third approaches,
a pair of primers was designed according to the following principle: the forward primer was complementary to
both species, since it was selected for the conserved gene region. Reverse primers were species-specific and were
designed for the 28S variable region. The two parasite species were distinguished by three-point mutations. Thus,
one pair of primers was complementary to L. mediterraneus, the other, to L. cephali. The amplified fragment length
analysis and the allele-specific real-time PCR demonstrated 100 % coincidence of genotyping results compared
with Sanger sequencing. The developed genotyping protocols can be used not only to distinguish two species of
Ligophorus from flathead mullet in ecological studies and veterinary practice but also for further development of
similar approaches for other monogeneans, among which there are many pathogenic species.
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Affiliation(s)
- E. A. Vodiasova
- A.O. Kovalevsky Institute of Biology of the Southern Seas of the Russian Academy of Sciences
| | - E. S. Chelebieva
- A.O. Kovalevsky Institute of Biology of the Southern Seas of the Russian Academy of Sciences
| | - O. V. Shikhat
- A.O. Kovalevsky Institute of Biology of the Southern Seas of the Russian Academy of Sciences
| | - D. M. Atopkin
- Federal Scientific Center of the East Asia Terrestrial Biodiversity, Far Eastern Branch of the Russian Academy of Sciences
| | - E. V. Dmitrieva
- A.O. Kovalevsky Institute of Biology of the Southern Seas of the Russian Academy of Sciences
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Yousef Kalafi E, Tan WB, Town C, Dhillon SK. Automated identification of Monogeneans using digital image processing and K-nearest neighbour approaches. BMC Bioinformatics 2016; 17:511. [PMID: 28155722 PMCID: PMC5260054 DOI: 10.1186/s12859-016-1376-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Monogeneans are flatworms (Platyhelminthes) that are primarily found on gills and skin of fishes. Monogenean parasites have attachment appendages at their haptoral regions that help them to move about the body surface and feed on skin and gill debris. Haptoral attachment organs consist of sclerotized hard parts such as hooks, anchors and marginal hooks. Monogenean species are differentiated based on their haptoral bars, anchors, marginal hooks, reproductive parts' (male and female copulatory organs) morphological characters and soft anatomical parts. The complex structure of these diagnostic organs and also their overlapping in microscopic digital images are impediments for developing fully automated identification system for monogeneans (LNCS 7666:256-263, 2012), (ISDA; 457-462, 2011), (J Zoolog Syst Evol Res 52(2): 95-99. 2013;). In this study images of hard parts of the haptoral organs such as bars and anchors are used to develop a fully automated identification technique for monogenean species identification by implementing image processing techniques and machine learning methods. RESULT Images of four monogenean species namely Sinodiplectanotrema malayanus, Trianchoratus pahangensis, Metahaliotrema mizellei and Metahaliotrema sp. (undescribed) were used to develop an automated technique for identification. K-nearest neighbour (KNN) was applied to classify the monogenean specimens based on the extracted features. 50% of the dataset was used for training and the other 50% was used as testing for system evaluation. Our approach demonstrated overall classification accuracy of 90%. In this study Leave One Out (LOO) cross validation is used for validation of our system and the accuracy is 91.25%. CONCLUSIONS The methods presented in this study facilitate fast and accurate fully automated classification of monogeneans at the species level. In future studies more classes will be included in the model, the time to capture the monogenean images will be reduced and improvements in extraction and selection of features will be implemented.
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Affiliation(s)
- Elham Yousef Kalafi
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Wooi Boon Tan
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Christopher Town
- Computer Laboratory, University of Cambridge, Cambridge, CB3 0FD, UK
| | - Sarinder Kaur Dhillon
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia. .,Computer Laboratory, University of Cambridge, Cambridge, CB3 0FD, UK.
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Khang TF, Soo OYM, Tan WB, Lim LHS. Monogenean anchor morphometry: systematic value, phylogenetic signal, and evolution. PeerJ 2016; 4:e1668. [PMID: 26966649 PMCID: PMC4783769 DOI: 10.7717/peerj.1668] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/18/2016] [Indexed: 12/22/2022] Open
Abstract
Background. Anchors are one of the important attachment appendages for monogenean parasites. Common descent and evolutionary processes have left their mark on anchor morphometry, in the form of patterns of shape and size variation useful for systematic and evolutionary studies. When combined with morphological and molecular data, analysis of anchor morphometry can potentially answer a wide range of biological questions. Materials and Methods. We used data from anchor morphometry, body size and morphology of 13 Ligophorus (Monogenea: Ancyrocephalidae) species infecting two marine mugilid (Teleostei: Mugilidae) fish hosts: Moolgarda buchanani (Bleeker) and Liza subviridis (Valenciennes) from Malaysia. Anchor shape and size data (n = 530) were generated using methods of geometric morphometrics. We used 28S rRNA, 18S rRNA, and ITS1 sequence data to infer a maximum likelihood phylogeny. We discriminated species using principal component and cluster analysis of shape data. Adams's K mult was used to detect phylogenetic signal in anchor shape. Phylogeny-correlated size and shape changes were investigated using continuous character mapping and directional statistics, respectively. We assessed morphological constraints in anchor morphometry using phylogenetic regression of anchor shape against body size and anchor size. Anchor morphological integration was studied using partial least squares method. The association between copulatory organ morphology and anchor shape and size in phylomorphospace was used to test the Rohde-Hobbs hypothesis. We created monogeneaGM, a new R package that integrates analyses of monogenean anchor geometric morphometric data with morphological and phylogenetic data. Results. We discriminated 12 of the 13 Ligophorus species using anchor shape data. Significant phylogenetic signal was detected in anchor shape. Thus, we discovered new morphological characters based on anchor shaft shape, the length between the inner root point and the outer root point, and the length between the inner root point and the dent point. The species on M. buchanani evolved larger, more robust anchors; those on L. subviridis evolved smaller, more delicate anchors. Anchor shape and size were significantly correlated, suggesting constraints in anchor evolution. Tight integration between the root and the point compartments within anchors confirms the anchor as a single, fully integrated module. The correlation between male copulatory organ morphology and size with anchor shape was consistent with predictions from the Rohde-Hobbs hypothesis. Conclusions. Monogenean anchors are tightly integrated structures, and their shape variation correlates strongly with phylogeny, thus underscoring their value for systematic and evolutionary biology studies. Our MonogeneaGM R package provides tools for researchers to mine biological insights from geometric morphometric data of speciose monogenean genera.
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Affiliation(s)
- Tsung Fei Khang
- Institute of Mathematical Sciences, University of Malaya, Kuala Lumpur, Malaysia
| | | | - Wooi Boon Tan
- Centre for Tropical Biodiversity Research, University of Malaya, Kuala Lumpur, Malaysia
| | - Lee Hong Susan Lim
- Institute of Biological Sciences, University of Malaya, Kuala Lumpur, Malaysia
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De Baets K, Dentzien-Dias P, Upeniece I, Verneau O, Donoghue PCJ. Constraining the Deep Origin of Parasitic Flatworms and Host-Interactions with Fossil Evidence. ADVANCES IN PARASITOLOGY 2015; 90:93-135. [PMID: 26597066 DOI: 10.1016/bs.apar.2015.06.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Novel fossil discoveries have contributed to our understanding of the evolutionary appearance of parasitism in flatworms. Furthermore, genetic analyses with greater coverage have shifted our views on the coevolution of parasitic flatworms and their hosts. The putative record of parasitic flatworms is consistent with extant host associations and so can be used to put constraints on the evolutionary origin of the parasites themselves. The future lies in new molecular clock analyses combined with additional discoveries of exceptionally preserved flatworms associated with hosts and coprolites. Besides direct evidence, the host fossil record and biogeography have the potential to constrain their evolutionary history, albeit with caution needed to avoid circularity, and a need for calibrations to be implemented in the most conservative way. This might result in imprecise, but accurate divergence estimates for the evolution of parasitic flatworms.
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Affiliation(s)
- Kenneth De Baets
- Fachgruppe PaläoUmwelt, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Paula Dentzien-Dias
- Núcleo de Oceanografia Geológica, Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Brazil
| | - Ieva Upeniece
- Department of Geology, University of Latvia, Riga, Latvia
| | - Olivier Verneau
- Centre de Formation et de Recherche sur les Environnements Méditerranéens, University of Perpignan Via Domitia, Perpignan, France; CNRS, Centre de Formation et de Recherche sur les Environnements Méditerranéens, Perpignan, France; Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - Philip C J Donoghue
- School of Earth Sciences, University of Bristol, Life Science Building, Bristol, UK
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Hahn C, Weiss SJ, Stojanovski S, Bachmann L. Co-Speciation of the Ectoparasite Gyrodactylus teuchis (Monogenea, Platyhelminthes) and Its Salmonid Hosts. PLoS One 2015; 10:e0127340. [PMID: 26080029 PMCID: PMC4469311 DOI: 10.1371/journal.pone.0127340] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/13/2015] [Indexed: 11/18/2022] Open
Abstract
Co-speciation is a fundamental concept of evolutionary biology and intuitively appealing, yet in practice hard to demonstrate as it is often blurred by other evolutionary processes. We investigate the phylogeographic history of the monogenean ectoparasites Gyrodactylus teuchis and G. truttae on European salmonids of the genus Salmo. Mitochondrial cytochrome oxidase subunit 1 and the nuclear ribosomal internal transcribed spacer 2 were sequenced for 189 Gyrodactylus individuals collected from 50 localities, distributed across most major European river systems, from the Iberian- to the Balkan Peninsula. Despite both anthropogenic and naturally caused admixture of the principal host lineages among major river basins, co-phylogenetic analyses revealed significant global congruence for host and parasite phylogenies, providing firm support for co-speciation of G. teuchis and its salmonid hosts brown trout (S. trutta) and Atlantic salmon (S. salar). The major split within G. teuchis, coinciding with the initial divergence of the hosts was dated to ~1.5 My BP, using a Bayesian framework based on an indirect calibration point obtained from the host phylogeny. The presence of G. teuchis in Europe thus predates some of the major Pleistocene glaciations. In contrast, G. truttae exhibited remarkably low intraspecific genetic diversity. Given the direct life cycle and potentially high transmission potential of gyrodactylids, this finding is interpreted as indication for a recent emergence (<60 ky BP) of G. truttae via a host-switch. Our study thus suggests that instances of two fundamentally different mechanisms of speciation (co-speciation vs. host-switching) may have occurred on the same hosts in Europe within a time span of less than 1.5 My in two gyrodactylid ectoparasite species.
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Affiliation(s)
- Christoph Hahn
- Natural History Museum, University of Oslo, 0318, Oslo, Norway
- School for Biological, Biomedical and Environmental Science, University of Hull, Hull, HU6 7RX, United Kingdom
- * E-mail:
| | - Steven J. Weiss
- Institute of Zoology, Karl-Franzens University of Graz, 8010, Graz, Austria
| | - Stojmir Stojanovski
- Department of Fish Parasitology, Hydrobiological Institute, 6000, Ohrid, R. Macedonia
| | - Lutz Bachmann
- Natural History Museum, University of Oslo, 0318, Oslo, Norway
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Strona G, Montano S, Seveso D, Galli P, Fattorini S. Identification of Monogenea made easier: a new statistical procedure for an automatic selection of diagnostic linear measurements in closely related species. J ZOOL SYST EVOL RES 2013. [DOI: 10.1111/jzs.12050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Giovanni Strona
- Department of Biotechnology and Biosciences; University of Milan-Bicocca; Milan Italy
| | - Simone Montano
- Department of Biotechnology and Biosciences; University of Milan-Bicocca; Milan Italy
| | - Davide Seveso
- Department of Biotechnology and Biosciences; University of Milan-Bicocca; Milan Italy
| | - Paolo Galli
- Department of Biotechnology and Biosciences; University of Milan-Bicocca; Milan Italy
| | - Simone Fattorini
- Department of Biotechnology and Biosciences; University of Milan-Bicocca; Milan Italy
- Azorean Biodiversity Group; Departamento de Ciências Agrárias; Universidade dos Açores; Terceira Azores Portugal
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