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Ondračková M, Seifertová M, Tkachenko MY, Vetešník L, Liu H, Demchenko V, Kvach Y. The parasites of a successful invader: monogeneans of the Asian topmouth gudgeon Pseudorasbora parva, with description of a new species of Gyrodactylus. Parasite 2023; 30:22. [PMID: 37326471 DOI: 10.1051/parasite/2023024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/30/2023] [Indexed: 06/17/2023] Open
Abstract
Monogenean parasites are often co-introduced with their fish hosts into novel areas. This study confirmed co-introduction of two dactylogyrids, Dactylogyrus squameus Gusev, 1955 and Bivaginogyrus obscurus (Gusev, 1955), and a newly described gyrodactylid species, Gyrodactylus pseudorasborae n. sp. into Europe along with their fish host, the invasive topmouth gudgeon Pseudorasbora parva (Temminck & Schlegel) from East Asia. All three species were observed in the lower Dnieper and middle Danube basin regions and had slightly larger haptoral hard parts than the same parasites in their native range. While dactylogyrids occurred sporadically, we recorded regular infection by G. pseudorasborae n. sp. at relatively high prevalence and abundance. This latter species was observed in both the native and non-native range of topmouth gudgeon, and resembles Gyrodactylus parvae You et al., 2008 recently described from P. parva in China. Both species were distinguished based on genetic analysis of their ITS rDNA sequence (6.6% difference), and morphometric differences in the marginal hooks and male copulatory organ. Phylogenetic analysis of dactylogyrid monogeneans showed that B. obscurus clustered with Dactylogyrus species parasitising Gobionidae and Xenocyprididae, including D. squameus, supporting recent suggestions of a paraphyletic origin of the Dactylogyrus genus. In addition to co-introduced parasites, topmouth gudgeon was infected with a local generalist, G. prostae Ergens, 1964, increasing the number of monogeneans acquired in Europe to three species. Nevertheless, monogenean infections were generally lower in non-native host populations, potentially giving an advantage to invading topmouth gudgeon.
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Affiliation(s)
- Markéta Ondračková
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Květná 8, 60365 Brno, Czech Republic
| | - Mária Seifertová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic
| | - Maria Yu Tkachenko
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Květná 8, 60365 Brno, Czech Republic
| | - Lukáš Vetešník
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Květná 8, 60365 Brno, Czech Republic
| | - Huanzhang Liu
- The Key Laboratory of Aquatic Biodiversity and Conservation of the Chinese Academy of Science, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Viktor Demchenko
- Institute of Marine Biology, National Academy of Sciences of Ukraine, 37 Pushkinska St., 65048 Odesa, Ukraine
| | - Yuriy Kvach
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Květná 8, 60365 Brno, Czech Republic - Institute of Marine Biology, National Academy of Sciences of Ukraine, 37 Pushkinska St., 65048 Odesa, Ukraine
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Berger CS, Bougas B, Côté G, Dumont JF, Bernatchez L. A qPCR-based method to detect the eel parasitic nematode Anguillicola crassus in intermediate and final hosts. Parasitol Res 2023; 122:1435-1443. [PMID: 37071205 DOI: 10.1007/s00436-023-07843-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 04/05/2023] [Indexed: 04/19/2023]
Abstract
Being able to systematically detect parasitic infection, even when no visual signs of infection are present, is crucial to the establishment of accurate conservation policies. The nematode Anguillicola crassus infects the swimbladder of anguillid species and is a potential threat for eel populations. In North America, naïve hosts such as the American eel Anguilla rostrata are affected by this infection. The accidental introduction of A. crassus following restocking programs may contribute to the actual decline of the American eel in Canada. We present a quantitative real time PCR-based method to detect A. crassus infection in final and intermediate hosts. We tested two protocols on samples from different geographical origins in Canada: 1) a general detection of A. crassus DNA in pools of young final hosts (glass eels) or crustacean intermediate hosts 2) a detection at the individual scale by analyzing swim bladders from elvers, or from adult yellow and silver eels. The DNA of A. crassus was detected in one pool of zooplankton (intermediate host) from the Richelieu River (Montérégie-Québec), as well as in individual swim bladders of 13 elvers from Grande and Petite Trinité rivers (Côte-Nord-Québec). We suggest that our qPCR approach could be used in a quantitative way to estimate the parasitic burden in individual swim bladders of elvers. Our method, which goes beyond most of previous developed protocols that restricted the diagnosis of A. crassus to the moment when it was fully established in its final host, should help to detect early A. crassus infection in nature.
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Affiliation(s)
- Chloé Suzanne Berger
- Institut de Biologie Intégrative Et Des Systèmes (IBIS), Université Laval, Québec, QC, Canada.
| | - Bérénice Bougas
- Institut de Biologie Intégrative Et Des Systèmes (IBIS), Université Laval, Québec, QC, Canada
| | - Guillaume Côté
- Ministère de L'Environnement, de La Lutte Contre Les Changements Climatiques, de La Faune Et Des Parcs (MELCCFP), Québec, QC, Canada
| | - Jean-François Dumont
- Ministère de L'Environnement, de La Lutte Contre Les Changements Climatiques, de La Faune Et Des Parcs (MELCCFP), Québec, QC, Canada
| | - Louis Bernatchez
- Institut de Biologie Intégrative Et Des Systèmes (IBIS), Université Laval, Québec, QC, Canada
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3
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Tahri M, Panfili J. 13-year population survey of the critically endangered European eel in the southern Mediterranean region (Algeria). JOURNAL OF FISH BIOLOGY 2023. [PMID: 37017233 DOI: 10.1111/jfb.15396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 04/03/2023] [Indexed: 05/03/2023]
Abstract
A 13-year biomonitoring survey was carried out on the European eel, Anguilla anguilla for the first time in North Africa (Algeria) where there is a serious lack of information on the species. The study targeted specimens populating the only four sites where the species is both potentially present and legally exploited (Lake Oubeira, Lake Tonga, Mellah lagoon and Mafragh estuary). A total of 1370 individuals were sampled ranging from 17 to 113 cm in length, 19 to 2642 g in weight and 0.7 months to 6.6 years old, age being estimated from otolith growth marks. Otolith interpretation and age estimation were generally unambiguous at all four sites. According to the EELREP silvering index, the highest proportion of silver females was captured in fresh water (46% in Lake Oubeira and 25% in Lake Tonga), whereas a third were present in brackish water (Mafragh and Mellah). The sex ratio was in favour of females, and silver males were found to mature early (mean length 40 ± 1 cm, mean weight 123 ± 28 g and mean age 2 ± 0.6 years). Growth differed at the four sites, and the growth rate was highest in Lake Oubeira and asymptotic length highest in Mellah lagoon. Metamorphosis from the yellow resident stage to the silver migrating stage occurred very early in the eels' continental life (between 3 and 4 years of age). Results highlight rapid growth in these Algerian sites, and earlier silvering than in eels living in European waters, suggesting different life-history traits of A. anguilla in North African waters, influenced by environmental conditions.
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Affiliation(s)
- Mardja Tahri
- Marine Sciences Department, Natural Sciences Faculty, Chadli BenDjedid University, El Tarf, Algeria
| | - Jacques Panfili
- IRD, MARBEC (Univ Montpellier, Ifremer, CNRS, IRD), Montpellier, France
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Towards an in-situ non-lethal rapid test to accurately detect the presence of the nematode parasite, Anguillicoloides crassus, in European eel, Anguilla anguilla. Parasitology 2022; 149:605-611. [PMID: 35042576 PMCID: PMC10090626 DOI: 10.1017/s0031182021002146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Anguillicoloides crassus is an invasive nematode parasite of the critically endangered European eel, Anguilla anguilla, and possibly one of the primary drivers of eel population collapse, impacting many features of eel physiology and life history. Early detection of the parasite is vital to limit the spread of A. crassus, to assess its potential impact on spawning biomass. However accurate diagnosis of infection could only be achieved via necropsy. To support eel fisheries management we developed a rapid, non-lethal, minimally invasive and in situ DNA-based method to infer the presence of the parasite in the swim bladder. Screening of 131 wild eels was undertaken between 2017 and 2019 in Ireland and UK to validate the procedure. DNA extractions and PCR were conducted using both a Qiagen Stool kit and in situ using Whatman qualitative filter paper No1 and a miniPCR DNA Discovery-System™. Primers were specifically designed to target the cytochrome oxidase mtDNA gene region and in situ extraction and amplification takes approximately 3 h for up to 16 individuals. Our in-situ diagnostic procedure demonstrated positive predictive values at 96% and negative predictive values at 87% by comparison to necropsy data. Our method could be a valuable tool in the hands of fisheries managers to enable infection control and help protect this iconic but critically endangered species.
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Capoccioni F, Leone C, Belpaire C, Malarvannan G, Poma G, De Matteis G, Tancioni L, Contò M, Failla S, Covaci A, Ciccotti E. Quality assessment of escaping silver eel (Anguilla anguilla L.) to support management and conservation strategies in Mediterranean coastal lagoons. ENVIRONMENTAL MONITORING AND ASSESSMENT 2020; 192:570. [PMID: 32770417 DOI: 10.1007/s10661-020-08533-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
Silver eel samples, collected from the lagoons of Fogliano and Caprolace (Italy), were investigated for a broad range of contaminants (29 polychlorinated biphenyls, 9 polybrominated diphenyl ethers, 5 dichlorodiphenyltrichloroethane, 5 chlordanes, hexachlorobenzene, 3 hexachlorocyclohexane, and 5 metals). Concentrations of targeted compounds stand for a general low contamination pattern. Infestation by Anguillicola crassus and virus infections were also examined. No parasite infestation was found, while infected silver eels had a low prevalence for EVEX, and, for the first time in the Mediterranean area, for AngHV-1. Overall, a good quality status of escaping silver eels, for both lagoons, was highlighted by the use of integrative Indexes. A quality assessment of the ecological status of the two lagoons was carried out developing an expert judgment approach, in order to characterize the habitat of eel stocks. A Final Pressure Index was derived, whose values showed an overall limited global anthropogenic impact acting on both lagoons. Results stand for the suitability of an integrated approach to assess lagoon habitats and eel local stocks quality. This could be proposed as a tool to identify sites yielding high quality eel spawners in the Mediterranean region, in order to set up suitable management frameworks, providing elements to appraise and discuss the potential of coastal lagoons in the Mediterranean region towards the recovery of the eel global stock.
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Affiliation(s)
- Fabrizio Capoccioni
- Centro di ricerca "Zootecnia e Acquacoltura" - Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria (CREA), Monterotondo, RM, Italy.
| | - Chiara Leone
- Dipartimento di Biologia, Università degli Studi di Roma "Tor Vergata", Rome, Italy
| | - Claude Belpaire
- Institute for Nature and Forest Research (INBO), Linkebeek, Belgium
| | | | - Giulia Poma
- Toxicological Centre, University of Antwerp, Wilrijk, Belgium
| | - Giovanna De Matteis
- Centro di ricerca "Zootecnia e Acquacoltura" - Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria (CREA), Monterotondo, RM, Italy
| | - Lorenzo Tancioni
- Dipartimento di Biologia, Università degli Studi di Roma "Tor Vergata", Rome, Italy
| | - Michela Contò
- Centro di ricerca "Zootecnia e Acquacoltura" - Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria (CREA), Monterotondo, RM, Italy
| | - Sebastiana Failla
- Centro di ricerca "Zootecnia e Acquacoltura" - Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria (CREA), Monterotondo, RM, Italy
| | - Adrian Covaci
- Toxicological Centre, University of Antwerp, Wilrijk, Belgium
| | - Eleonora Ciccotti
- Dipartimento di Biologia, Università degli Studi di Roma "Tor Vergata", Rome, Italy
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Richards JL, Sheng V, Yi CW, Ying CL, Ting NS, Sadovy Y, Baker D. Prevalence of critically endangered European eel ( Anguilla anguilla) in Hong Kong supermarkets. SCIENCE ADVANCES 2020; 6:eaay0317. [PMID: 32181342 PMCID: PMC7056311 DOI: 10.1126/sciadv.aay0317] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 12/11/2019] [Indexed: 05/27/2023]
Abstract
European eel (Anguilla anguilla) is a critically endangered species requiring CITES permits for international trade. Despite the fact that no imports to Hong Kong were declared within the last 2 years, our study found that this species is still commonly sold in major supermarket chains across Hong Kong. In a COI barcoding survey of 49 retail vendors encompassing 13 brands, 9 of 13 carried A. anguilla, and 45% of all eel products available at retail outlets (n = 49) were unambiguously identified as A. anguilla. Considering the visual similarity of eel species and disproportionate amount of undeclared A. anguilla available for consumption, this finding raises urgent concerns regarding the enforcement of international CITES trade regulations. Furthermore, the prevalence of A. anguilla in supermarkets highlights how illicit wildlife products are not solely limited to specialized affluent buyers; some species have entered mainstream distribution networks for the average consumer.
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Affiliation(s)
- John L. Richards
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
- Swire Institute of Marine Science, The University of Hong Kong, Cape d’Aguilar, Hong Kong, China
| | - Victoria Sheng
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
- Swire Institute of Marine Science, The University of Hong Kong, Cape d’Aguilar, Hong Kong, China
| | - Chung Wing Yi
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Chan Lai Ying
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Ng Sin Ting
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Yvonne Sadovy
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
- Swire Institute of Marine Science, The University of Hong Kong, Cape d’Aguilar, Hong Kong, China
| | - David Baker
- The University of Hong Kong, Pok Fu Lam, Hong Kong, China
- Swire Institute of Marine Science, The University of Hong Kong, Cape d’Aguilar, Hong Kong, China
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7
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Bracamonte SE, Johnston PR, Knopf K, Monaghan MT. Experimental infection with Anguillicola crassus alters immune gene expression in both spleen and head kidney of the European eel (Anguilla anguilla). Mar Genomics 2019; 45:28-37. [DOI: 10.1016/j.margen.2018.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/21/2018] [Accepted: 12/21/2018] [Indexed: 11/25/2022]
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8
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Schneebauer G, Dirks RP, Pelster B. Anguillicola crassus infection affects mRNA expression levels in gas gland tissue of European yellow and silver eel. PLoS One 2017; 12:e0183128. [PMID: 28817599 PMCID: PMC5560681 DOI: 10.1371/journal.pone.0183128] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 07/31/2017] [Indexed: 12/31/2022] Open
Abstract
Using Illumina sequencing, we investigated transcriptional changes caused by the nematode Anguillicola crassus within yellow and silver eels by comparing swimbladder samples of uninfected yellow with infected yellow eels, and uninfected silver with infected silver eels, respectively. In yellow eel gas gland, the infection caused a modification of steady state mRNA levels of 1675 genes, most of them being upregulated. Functional annotation analysis based on GO terms was used to categorize identified genes with regard to swimbladder metabolism or response to the infection. In yellow eels, the most prominent category was 'immune response', including various inflammatory components, complement proteins, and immunoglobulins. The elevated expression of several glucose and monocarboxylate transporters indicated an attempt to maintain the level of glucose metabolism, even in due to the infection thickened swimbladder tissue. In silver eel swimbladder tissue, on the contrary, the mRNA levels of only 291 genes were affected. Genes in the categories 'glucose metabolism' and 'ROS metabolism' barely responded to the infection and even the reaction of the immune system was much less pronounced compared to infected yellow eels. However, in the category 'extracellular matrix', the mRNA levels of several mucin genes were strongly elevated, suggesting increased mucus production as a defense reaction against the parasite. The present study revealed a strong reaction to an Anguillicola crassus infection on mRNA expression levels in swimbladder tissue of yellow eels, whereas in silver eels the changes ware almost negligible. A possible explanation for this difference is that the silvering process requires so much energy that there is not much scope to cope with the additional challenge of a nematode infection. Another possible explanation could be that gas-secreting activity of the silver eel swimbladder was largely reduced, which could coincide with a reduced responsiveness to other challenges, like a nematode infection.
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Affiliation(s)
- Gabriel Schneebauer
- Institute of Zoology, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences, University Innsbruck, Innsbruck, Austria
| | | | - Bernd Pelster
- Institute of Zoology, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences, University Innsbruck, Innsbruck, Austria
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Schneebauer G, Hanel R, Pelster B. Anguillicola crassus impairs the silvering-related enhancements of the ROS defense capacity in swimbladder tissue of the European eel (Anguilla anguilla). J Comp Physiol B 2016; 186:867-77. [PMID: 27146148 PMCID: PMC5009179 DOI: 10.1007/s00360-016-0994-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/22/2016] [Accepted: 04/23/2016] [Indexed: 01/07/2023]
Abstract
In a process called silvering, European eels prepare for their long-distance migration from European freshwater systems to the Sargasso Sea for reproduction. During this journey, eels perform extended diel vertical migrations, and the concomitant changes in hydrostatic pressure significantly affect the swimbladder, functioning as a buoyancy organ. As the swimbladder is primarily filled with oxygen, the tissue has to cope with extreme hyperoxic conditions, which typically are accompanied by the generation of reactive oxygen species (ROS) and oxidative stress. In addition, since the introduction of the parasitic nematode Anguillicola crassus in the early 1980s, swimbladder function of most of the European eels is impaired by the infection with this parasite. However, the exact pathways to detoxify ROS and how these pathways are affected by silvering or the infection are still unknown. In swimbladder and muscle tissue from uninfected and infected yellow, and from uninfected and infected silver eels, we measured the level of lipid peroxidation, which increases with ROS stress. To assess the capacity of the ROS defense systems, we analyzed the activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and glutathione reductase (GR), and determined the concentration of the antioxidant glutathione (GSH + GSSG). In swimbladder tissue, we found increased concentrations of GSH + GSSG as well as higher activities of SOD, GPx and GR, suggesting that SOD and the glutathione cycle are important for ROS detoxification. Comparing swimbladder tissue of uninfected yellow with uninfected silver eels, the concentration of GSH + GSSG and the activity of SOD were higher after silvering, corresponding with lower levels of lipid peroxidation. Whereas in yellow eels the infection with A. crassus had no effect, in silver eels the capacity to cope with ROS was significantly impaired. In muscle tissue, silvering or the infection only affected the activity of SOD but in exactly the same way as in swimbladder tissue.
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Affiliation(s)
- Gabriel Schneebauer
- Institut für Zoologie, Leopold-Franzens-Universität Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
- Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | | | - Bernd Pelster
- Institut für Zoologie, Leopold-Franzens-Universität Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria.
- Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria.
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10
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Pelster B, Schneebauer G, Dirks RP. Anguillicola crassus Infection Significantly Affects the Silvering Related Modifications in Steady State mRNA Levels in Gas Gland Tissue of the European Eel. Front Physiol 2016; 7:175. [PMID: 27242549 PMCID: PMC4876612 DOI: 10.3389/fphys.2016.00175] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 05/02/2016] [Indexed: 11/20/2022] Open
Abstract
Using Illumina sequencing, transcriptional changes occurring during silvering in swimbladder tissue of the European eel have been analyzed by comparison of yellow and silver eel tissue samples. Functional annotation analysis based on GO terms revealed significant expression changes in a number of genes related to the extracellular matrix, important for the control of gas permeability of the swimbladder, and to reactive oxygen species (ROS) defense, important to cope with ROS generated under hyperbaric oxygen partial pressures. Focusing on swimbladder tissue metabolism, levels of several mRNA species encoding glucose transport proteins were several-fold higher in silver eels, while enzymes of the glycolytic pathway were not affected. The significantly higher steady state level of a transcript encoding for membrane bound carbonic anhydrase, however, suggested that CO2 production in the pentose phosphate shunt and diffusion of CO2 was of particular importance in silver eel swimbladder. In addition, the mRNA level of a large number of genes related to immune response and to sexual maturation was significantly modified in the silver eel swimbladder. The modification of several processes related to protein metabolism and transport, cell cycle, and apoptosis suggested that these changes in swimbladder metabolism and permeability were achieved by increasing cell turn-over. The impact of an infection of the swimbladder with the nematode Anguillicola crassus has been assessed by comparing these expression changes with expression changes observed between uninfected yellow eel swimbladder tissue and infected silver eel swimbladder tissue. In contrast to uninfected silver eel swimbladder tissue, in infected tissue the mRNA level of several glycolytic enzymes was significantly elevated, and with respect to extracellular matrix, several mucin genes were many-fold higher in their mRNA level. Modification of many immune related genes and of the functional categories “response to DNA damage stimulus” and “cellular response to stress” illustrated the damaging effect of the nematode infection. This study has identified a range of cellular processes in the swimbladder of silver eels that appear to be altered by nematode infection. These altered cellular processes could contribute to detrimental changes in swimbladder function that, in turn, may lead to impairment of spawning migration.
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Affiliation(s)
- Bernd Pelster
- Institute of Zoology, University of InnsbruckInnsbruck, Austria; Center for Molecular Biosciences, University of InnsbruckInnsbruck, Austria
| | - Gabriel Schneebauer
- Institute of Zoology, University of InnsbruckInnsbruck, Austria; Center for Molecular Biosciences, University of InnsbruckInnsbruck, Austria
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11
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Keppel M, Dangel KC, Sures B. The Hsp70 response of Anguillicola species to host-specific stressors. Parasitol Res 2016; 115:2149-54. [PMID: 26920569 DOI: 10.1007/s00436-016-4956-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 02/11/2016] [Indexed: 12/20/2022]
Abstract
The present study is based on infection experiments of two different swim bladder parasite species, Anguillicola crassus Kuwahara et al., 1974 and Anguillicola novaezelandiae Moravec and Taraschewski, 1988, which were experimentally transferred to the two eel species Anguilla anguilla Linnaeus, 1758 and Anguilla japonica Temmink and Schlegel, 1846, respectively. The host-parasite groups were selected due to their different grades of mutual adaptation. The main aim of this study was to analyze the stress responses within the parasites, which were confronted with different hosts, i.e. with different stressors related to the respective host. For this purpose, mean intensities, recovery rates, larvae output, and levels of synthesized heat shock proteins (Hsp70) were determined in nematodes of each infection group. Increased stress responses were detected in the endemic system of A. crassus parasitizing A. japonica and A. crassus in its recently acquired host A. anguilla, which seems to be associated with the immune response of the particular host species and the expenditure of energy on producing larvae. A. novaezelandiae showed overall weak activities in its unknown host species A. japonica, with the lowest recovery rate of all examined groups neither featuring elevated Hsp responses, nor a high mean intensity, nor any reproductive output. On the contrary, in A. anguilla, the parasite reached higher recovery rates, mean intensities, and reproductive output, but no increased Hsp70 levels could be detected. The four considered factors proved partially interdependent, whereas few results did not follow a clear pattern.
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Affiliation(s)
- M Keppel
- Department of Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Universitaetsstrasse 5, 45141, Essen, Germany.
| | - K C Dangel
- Department of Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Universitaetsstrasse 5, 45141, Essen, Germany
| | - B Sures
- Department of Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Universitaetsstrasse 5, 45141, Essen, Germany.,Department of Zoology, University of Johannesburg, PO Box 524, Auckland Park 2006, Johannesburg, South Africa
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Nowosad J, Kucharczyk D, Czarkowski TK, Kwasek K. Changes in Body Weight and Eye Size in Female European Eel Kept in Fresh and Salt Water. ITALIAN JOURNAL OF ANIMAL SCIENCE 2016. [DOI: 10.4081/ijas.2014.3144] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Jacoby DM, Casselman JM, Crook V, DeLucia MB, Ahn H, Kaifu K, Kurwie T, Sasal P, Silfvergrip AM, Smith KG, Uchida K, Walker AM, Gollock MJ. Synergistic patterns of threat and the challenges facing global anguillid eel conservation. Glob Ecol Conserv 2015. [DOI: 10.1016/j.gecco.2015.07.009] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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14
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Newbold LR, Hockley FA, Williams CF, Cable J, Reading AJ, Auchterlonie N, Kemp PS. Relationship between European eel Anguilla anguilla infection with non-native parasites and swimming behaviour on encountering accelerating flow. JOURNAL OF FISH BIOLOGY 2015; 86:1519-1533. [PMID: 25801939 DOI: 10.1111/jfb.12659] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 02/05/2015] [Indexed: 06/04/2023]
Abstract
The effect of Anguillicola crassus, Pseudodactylogyrus bini and Pseudodactylogyrus anguillae infection on the behaviour of downstream migrating adult European eels Anguilla anguilla as they encountered accelerating water velocity, common at engineered structures where flow is constricted (e.g. weirs and bypass systems), was evaluated in an experimental flume. The probability of reacting to, and rejecting, the velocity gradient was positively related to A. crassus larval, adult and total abundance. High abundance of Pseudodactylogyrus spp. reduced this effect, but A. crassus was the strongest parasitic factor associated with fish behaviour, and abundance was positively related to delay in downstream passage. Delayed downstream migration at hydraulic gradients associated with riverine anthropogenic structures could result in additional energetic expenditure for migrating A. anguilla already challenged by A. crassus infection.
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Affiliation(s)
- L R Newbold
- The International Centre for Ecohydraulics Research, Faculty of Engineering and the Environment, Highfield Campus, University of Southampton, Southampton, Hampshire SO17 1BJ, U.K
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Pelster B. Swimbladder function and the spawning migration of the European eel Anguilla anguilla. Front Physiol 2015; 5:486. [PMID: 25646080 PMCID: PMC4297919 DOI: 10.3389/fphys.2014.00486] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 11/25/2014] [Indexed: 11/17/2022] Open
Abstract
The spawning migration of the European eel is an extensive journey over 5000 to 7000 km from the European coast to the Sargasso Sea. Eels do not feed during this journey and on-board fuels must be sufficient to support the journey of 3.5 to 6 month, as well as sexual maturation and the spawning activity. Swimming of eels appears to be quite energy efficient compared to other fish species, and elevated hydrostatic pressure has been shown to even reduce the costs of transport. Recent studies revealed, however, that during traveling eels perform extensive diurnal migrations and swim at a depth of about 100-300 m at night time, but go down to 600-1000 m at day time. At a depth of 200 m eels are exposed to a hydrostatic pressure of 21 atmospheres (2.13 MPa), while at 800 m hydrostatic pressure increases to 81 atmospheres (8.21 MPa). Accordingly, without any compensation at a depth of 800 m swimbladder volume will be reduced to about 25% of the volume established with neutral buoyancy at 200 m. Consequently, these diurnal changes in depth must be taken into consideration for a calculation of the energy requirements of the spawning migration. Without compensation a compression of the swimbladder will result in a status of negative buoyancy, which makes swimming more costly. Trying to keep the status of neutral buoyancy during descent by gas secretion into the swimbladder in turn requires metabolic activity to enhance swimbladder perfusion and for acid production of the gas gland cells to stimulate gas secretion. During ascent gas is passively removed from the swimbladder in the resorbing section and in the blood transported to the gills, where it is lost into the water. Accordingly, the swimbladder appears to be a crucial organ for the spawning migration. It can be assumed that an impairment of swimbladder function for example due to an infection with the nematode Anguillicola crassus significantly threatens the success of the spawning migration.
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Affiliation(s)
- Bernd Pelster
- Institute for Zoology, University of InnsbruckInnsbruck, Austria
- Center for Molecular Biosciences, University of InnsbruckInnsbruck, Austria
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