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Khalaf A, Francis O, Blaxter ML. Genome evolution in intracellular parasites: Microsporidia and Apicomplexa. J Eukaryot Microbiol 2024:e13033. [PMID: 38785208 DOI: 10.1111/jeu.13033] [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: 02/14/2024] [Revised: 03/29/2024] [Accepted: 05/02/2024] [Indexed: 05/25/2024]
Abstract
Microsporidia and Apicomplexa are eukaryotic, single-celled, intracellular parasites with huge public health and economic importance. Typically, these parasites are studied separately, emphasizing their uniqueness and diversity. In this review, we explore the huge amount of genomic data that has recently become available for the two groups. We compare and contrast their genome evolution and discuss how their transitions to intracellular life may have shaped it. In particular, we explore genome reduction and compaction, genome expansion and ploidy, gene shuffling and rearrangements, and the evolution of centromeres and telomeres.
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Affiliation(s)
- Amjad Khalaf
- Tree of Life, Wellcome Sanger Institute, Cambridge, UK
| | - Ore Francis
- Tree of Life, Wellcome Sanger Institute, Cambridge, UK
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Hiltunen Thorén M, Onuț-Brännström I, Alfjorden A, Pecková H, Swords F, Hooper C, Holzer AS, Bass D, Burki F. Comparative genomics of Ascetosporea gives new insight into the evolutionary basis for animal parasitism in Rhizaria. BMC Biol 2024; 22:103. [PMID: 38702750 PMCID: PMC11069148 DOI: 10.1186/s12915-024-01898-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 04/22/2024] [Indexed: 05/06/2024] Open
Abstract
BACKGROUND Ascetosporea (Endomyxa, Rhizaria) is a group of unicellular parasites infecting aquatic invertebrates. They are increasingly being recognized as widespread and important in marine environments, causing large annual losses in invertebrate aquaculture. Despite their importance, little molecular data of Ascetosporea exist, with only two genome assemblies published to date. Accordingly, the evolutionary origin of these parasites is unclear, including their phylogenetic position and the genomic adaptations that accompanied the transition from a free-living lifestyle to parasitism. Here, we sequenced and assembled three new ascetosporean genomes, as well as the genome of a closely related amphizoic species, to investigate the phylogeny, origin, and genomic adaptations to parasitism in Ascetosporea. RESULTS Using a phylogenomic approach, we confirm the monophyly of Ascetosporea and show that Paramyxida group with Mikrocytida, with Haplosporida being sister to both groups. We report that the genomes of these parasites are relatively small (12-36 Mb) and gene-sparse (~ 2300-5200 genes), while containing surprisingly high amounts of non-coding sequence (~ 70-90% of the genomes). Performing gene-tree aware ancestral reconstruction of gene families, we demonstrate extensive gene losses at the origin of parasitism in Ascetosporea, primarily of metabolic functions, and little gene gain except on terminal branches. Finally, we highlight some functional gene classes that have undergone expansions during evolution of the group. CONCLUSIONS We present important new genomic information from a lineage of enigmatic but important parasites of invertebrates and illuminate some of the genomic innovations accompanying the evolutionary transition to parasitism in this lineage. Our results and data provide a genetic basis for the development of control measures against these parasites.
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Affiliation(s)
- Markus Hiltunen Thorén
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden.
- Present Address: Department of Ecology, Environment and Plant Sciences, Stockholm University, Svante Arrhenius V. 20 A, Stockholm, SE-114 18, Sweden.
- Present Address: The Royal Swedish Academy of Sciences, Stockholm, SE-114 18, Sweden.
| | - Ioana Onuț-Brännström
- Present Address: Department of Ecology and Genetics, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden
- Present Address: Natural History Museum, Oslo University, Oslo, 0562, Norway
| | - Anders Alfjorden
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden
| | - Hana Pecková
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, České Budějovice, 370 05, Czech Republic
| | - Fiona Swords
- Marine Institute, Rinville, Oranmore, H91R673, Ireland
| | - Chantelle Hooper
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth Laboratory, Weymouth, Dorset, DT4 8UB, UK
- Sustainable Aquaculture Futures, Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Astrid S Holzer
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, České Budějovice, 370 05, Czech Republic
- Division of Fish Health, University of Veterinary Medicine, Veterinärplatz 1, Vienna, 1210, Austria
| | - David Bass
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth Laboratory, Weymouth, Dorset, DT4 8UB, UK
- Sustainable Aquaculture Futures, Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Natural History Museum (NHM), Science, London, SW7 5BD, UK
| | - Fabien Burki
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden.
- Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
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Trznadel M, Holt CC, Livingston SJ, Kwong WK, Keeling PJ. Coral-infecting parasites in cold marine ecosystems. Curr Biol 2024; 34:1810-1816.e4. [PMID: 38608678 DOI: 10.1016/j.cub.2024.03.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/17/2024] [Accepted: 03/14/2024] [Indexed: 04/14/2024]
Abstract
Coral reefs are a biodiversity hotspot,1,2 and the association between coral and intracellular dinoflagellates is a model for endosymbiosis.3,4 Recently, corals and related anthozoans have also been found to harbor another kind of endosymbiont, apicomplexans called corallicolids.5 Apicomplexans are a diverse lineage of obligate intracellular parasites6 that include human pathogens such as the malaria parasite, Plasmodium.7 Global environmental sequencing shows corallicolids are tightly associated with tropical and subtropical reef environments,5,8,9 where they infect diverse corals across a range of depths in many reef systems, and correlate with host mortality during bleaching events.10 All of this points to corallicolids being ecologically significant to coral reefs, but it is also possible they are even more widely distributed because most environmental sampling is biased against parasites that maintain a tight association with their hosts throughout their life cycle. We tested the global distribution of corallicolids using a more direct approach, by specifically targeting potential anthozoan host animals from cold/temperate marine waters outside the coral reef context. We found that corallicolids are in fact common in such hosts, in some cases at high frequency, and that they infect the same tissue as parasites from topical coral reefs. Parasite phylogeny suggests corallicolids move between hosts and habitats relatively frequently, but that biogeography is more conserved. Overall, these results greatly expand the range of corallicolids beyond coral reefs, suggesting they are globally distributed parasites of marine anthozoans, which also illustrates significant blind spots that result from strategies commonly used to sample microbial biodiversity.
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Affiliation(s)
- Morelia Trznadel
- Botany Department, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Corey C Holt
- Botany Department, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Samuel J Livingston
- Botany Department, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Waldan K Kwong
- Botany Department, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Patrick J Keeling
- Botany Department, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada.
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Cano I, Wood G, Stone D, Noyer M, Canier L, Arzul I. Loop-Mediated Isothermal Amplification for the Fast Detection of Bonamia ostreae and Bonamia exitiosa in Flat Oysters. Pathogens 2024; 13:132. [PMID: 38392870 PMCID: PMC10893247 DOI: 10.3390/pathogens13020132] [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: 12/27/2023] [Revised: 01/26/2024] [Accepted: 01/27/2024] [Indexed: 02/25/2024] Open
Abstract
The haplosporidian parasites Bonamia ostreae (BO) and B. exitiosa (BE) are serious oyster pathogens. Two independent laboratories evaluated fluorescence real-time loop-mediated isothermal amplification (LAMP) assays for rapidly detecting these parasites. Specific LAMP assays were designed on the BO actin-1 and BE actin genes. A further generic assay was conceived on a conserved region of the 18S gene to detect both Bonamia species. The optimal reaction temperature varied from 65 to 67 °C depending on the test and instrument. Melting temperatures were 89.8-90.2 °C, 87.0-87.6 °C, and 86.2-86.6 °C for each of the BO, BE, and generic assays. The analytical sensitivity of these assays was 50 copies/µL in a 30 min run. The BO and BE test sensitivity was ~1 log lower than a real-time PCR, while the generic test sensitivity was similar to the real-time PCR. Both the BO and BE assays were shown to be specific; however, the generic assay potentially cross-reacts with Haplosporidium costale. The performance of the LAMP assays evaluated on samples of known status detected positives within 7-20 min with a test accuracy of 100% for the BO and generic tests and a 95.8% accuracy for BE. The ease of use, rapidity and affordability of these tests allow for field deployment.
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Affiliation(s)
- Irene Cano
- The International Centre of Excellence for Aquatic Animal Health, Cefas Weymouth Laboratory, Weymouth, Dorset DT4 8UB, UK (D.S.)
| | - Gareth Wood
- The International Centre of Excellence for Aquatic Animal Health, Cefas Weymouth Laboratory, Weymouth, Dorset DT4 8UB, UK (D.S.)
| | - David Stone
- The International Centre of Excellence for Aquatic Animal Health, Cefas Weymouth Laboratory, Weymouth, Dorset DT4 8UB, UK (D.S.)
| | - Mathilde Noyer
- The Institut Français de Recherche pour l’Exploitation de la Mer Ifremer, RBE-SG2M-ASIM, Station de La Tremblade, Avenue de Mus de Loup, La Tremblade, 17390 Brest, France; (M.N.); (L.C.); (I.A.)
| | - Lydie Canier
- The Institut Français de Recherche pour l’Exploitation de la Mer Ifremer, RBE-SG2M-ASIM, Station de La Tremblade, Avenue de Mus de Loup, La Tremblade, 17390 Brest, France; (M.N.); (L.C.); (I.A.)
| | - Isabelle Arzul
- The Institut Français de Recherche pour l’Exploitation de la Mer Ifremer, RBE-SG2M-ASIM, Station de La Tremblade, Avenue de Mus de Loup, La Tremblade, 17390 Brest, France; (M.N.); (L.C.); (I.A.)
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Žárský V, Karnkowska A, Boscaro V, Trznadel M, Whelan TA, Hiltunen-Thorén M, Onut-Brännström I, Abbott CL, Fast NM, Burki F, Keeling PJ. Contrasting outcomes of genome reduction in mikrocytids and microsporidians. BMC Biol 2023; 21:137. [PMID: 37280585 DOI: 10.1186/s12915-023-01635-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/26/2023] [Indexed: 06/08/2023] Open
Abstract
BACKGROUND Intracellular symbionts often undergo genome reduction, losing both coding and non-coding DNA in a process that ultimately produces small, gene-dense genomes with few genes. Among eukaryotes, an extreme example is found in microsporidians, which are anaerobic, obligate intracellular parasites related to fungi that have the smallest nuclear genomes known (except for the relic nucleomorphs of some secondary plastids). Mikrocytids are superficially similar to microsporidians: they are also small, reduced, obligate parasites; however, as they belong to a very different branch of the tree of eukaryotes, the rhizarians, such similarities must have evolved in parallel. Since little genomic data are available from mikrocytids, we assembled a draft genome of the type species, Mikrocytos mackini, and compared the genomic architecture and content of microsporidians and mikrocytids to identify common characteristics of reduction and possible convergent evolution. RESULTS At the coarsest level, the genome of M. mackini does not exhibit signs of extreme genome reduction; at 49.7 Mbp with 14,372 genes, the assembly is much larger and gene-rich than those of microsporidians. However, much of the genomic sequence and most (8075) of the protein-coding genes code for transposons, and may not contribute much of functional relevance to the parasite. Indeed, the energy and carbon metabolism of M. mackini share several similarities with those of microsporidians. Overall, the predicted proteome involved in cellular functions is quite reduced and gene sequences are extremely divergent. Microsporidians and mikrocytids also share highly reduced spliceosomes that have retained a strikingly similar subset of proteins despite having reduced independently. In contrast, the spliceosomal introns in mikrocytids are very different from those of microsporidians in that they are numerous, conserved in sequence, and constrained to an exceptionally narrow size range (all 16 or 17 nucleotides long) at the shortest extreme of known intron lengths. CONCLUSIONS Nuclear genome reduction has taken place many times and has proceeded along different routes in different lineages. Mikrocytids show a mix of similarities and differences with other extreme cases, including uncoupling the actual size of a genome with its functional reduction.
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Affiliation(s)
- Vojtečh Žárský
- Department of Botany, University of British Columbia, V6T 1Z4, Vancouver, 3529-6270 University Boulevard, BC, Canada
| | - Anna Karnkowska
- Department of Botany, University of British Columbia, V6T 1Z4, Vancouver, 3529-6270 University Boulevard, BC, Canada
- Institute of Evolutionary Biology, Faculty of Biology, University of Warsaw, 02-089, Warsaw, Poland
| | - Vittorio Boscaro
- Department of Botany, University of British Columbia, V6T 1Z4, Vancouver, 3529-6270 University Boulevard, BC, Canada.
| | - Morelia Trznadel
- Department of Botany, University of British Columbia, V6T 1Z4, Vancouver, 3529-6270 University Boulevard, BC, Canada
| | - Thomas A Whelan
- Department of Botany, University of British Columbia, V6T 1Z4, Vancouver, 3529-6270 University Boulevard, BC, Canada
| | - Markus Hiltunen-Thorén
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, 752 36, Uppsala, Sweden
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Ioana Onut-Brännström
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, 752 36, Uppsala, Sweden
- Department of Ecology and Genetics, Uppsala University, 752 36, Uppsala, Sweden
- Natural History Museum, University of Oslo, 0562, Oslo, Norway
| | - Cathryn L Abbott
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, V9T 6N7, Canada
| | - Naomi M Fast
- Department of Botany, University of British Columbia, V6T 1Z4, Vancouver, 3529-6270 University Boulevard, BC, Canada
| | - Fabien Burki
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, 752 36, Uppsala, Sweden
| | - Patrick J Keeling
- Department of Botany, University of British Columbia, V6T 1Z4, Vancouver, 3529-6270 University Boulevard, BC, Canada.
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Moro-Martínez I, Vázquez-Luis M, García-March JR, Prado P, Mičić M, Catanese G. Haplosporidium pinnae Parasite Detection in Seawater Samples. Microorganisms 2023; 11:1146. [PMID: 37317120 DOI: 10.3390/microorganisms11051146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 04/20/2023] [Accepted: 04/26/2023] [Indexed: 06/16/2023] Open
Abstract
In this study, we investigated the presence of the parasite Haplosporidium pinnae, which is a pathogen for the bivalve Pinna nobilis, in water samples from different environments. Fifteen mantle samples of P. nobilis infected by H. pinnae were used to characterize the ribosomal unit of this parasite. The obtained sequences were employed to develop a method for eDNA detection of H. pinnae. We collected 56 water samples (from aquaria, open sea and sanctuaries) for testing the methodology. In this work, we developed three different PCRs generating amplicons of different lengths to determine the level of degradation of the DNA, since the status of H. pinnae in water and, therefore, its infectious capacity are unknown. The results showed the ability of the method to detect H. pinnae in sea waters from different areas persistent in the environment but with different degrees of DNA fragmentation. This developed method offers a new tool for preventive analysis for monitoring areas and to better understand the life cycle and the spread of this parasite.
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Affiliation(s)
- Irene Moro-Martínez
- LIMIA-IRFAP Laboratorio de Investigaciones Marinas y Acuicultura-Govern de les Illes Balears, 07157 Port d'Andratx, Spain
| | - Maite Vázquez-Luis
- IEO-CSIC, Centro Oceanográfico de Baleares Instituto Español de Oceanografía, 07010 Palma de Mallorca, Spain
| | - José Rafael García-March
- IMEDMAR-UCV Instituto de Investigación en Medio Ambiente y Ciencia Marina, Universidad Católica de Valencia, 03710 Calpe, Spain
| | | | - Milena Mičić
- Aquarium Pula d.o.o., Ulica Verudella 33, 52100 Pula, Croatia
| | - Gaetano Catanese
- LIMIA-IRFAP Laboratorio de Investigaciones Marinas y Acuicultura-Govern de les Illes Balears, 07157 Port d'Andratx, Spain
- INAGEA (UIB)-Instituto de Investigaciones Agroambientales y de Economía del Agua, Universidad de las Islas Baleares, Carretera de Valldemossa, km 7.5, 07122 Palma, Spain
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Bass D, Christison KW, Stentiford GD, Cook LSJ, Hartikainen H. Environmental DNA/RNA for pathogen and parasite detection, surveillance, and ecology. Trends Parasitol 2023; 39:285-304. [PMID: 36759269 DOI: 10.1016/j.pt.2022.12.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/20/2022] [Accepted: 12/26/2022] [Indexed: 02/11/2023]
Abstract
Detection of pathogens, parasites, and other symbionts in environmental samples via eDNA/eRNA (collectively eNA) is an increasingly important source of information about their occurrence and activity. There is great potential for using such detections as a proxy for infection of host organisms in connected habitats, for pathogen monitoring and surveillance, and for early warning systems for disease. However, many factors require consideration, and appropriate methods developed and verified, in order that eNA detections can be reliably interpreted and adopted for surveillance and assessment of disease risk, and potentially inclusion in international standards, such as the World Organisation for Animal Health guidelines. Disease manifestation results from host-symbiont-environment interactions between hosts, demanding a multifactorial approach to interpretation of eNA signals.
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Affiliation(s)
- David Bass
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK; Sustainable Aquaculture Futures, Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, UK.
| | - Kevin W Christison
- Department of Biodiversity and Conservation Biology, University of the Western Cape, Private Bag X17, Bellville, 7535, South Africa; Department of Forestry, Fisheries and the Environment, Private Bag X2, Vlaeberg, 8012, South Africa
| | - Grant D Stentiford
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK; Sustainable Aquaculture Futures, Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, UK
| | - Lauren S J Cook
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK; Royal Holloway, University of London, Egham Hill, Egham TW20 0EX, UK
| | - Hanna Hartikainen
- University of Nottingham, School of Life Sciences, University Park, NG7 2RD, Nottingham, UK
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Lara E, Singer D, Geisen S. Discrepancies between prokaryotes and eukaryotes need to be considered in soil DNA-based studies. Environ Microbiol 2022; 24:3829-3839. [PMID: 35437903 PMCID: PMC9790305 DOI: 10.1111/1462-2920.16019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 12/30/2022]
Abstract
Metabarcoding approaches are exponentially increasing our understanding of soil biodiversity, with a major focus on the bacterial part of the microbiome. Part of the soil diversity are also eukaryotes that include fungi, algae, protists and Metazoa. Nowadays, soil eukaryotes are targeted with the same approaches developed for bacteria and archaea (prokaryotes). However, fundamental differences exist between domains. After providing a short historical overview of the developments of metabarcoding applied to environmental microbiology, we compile the most important differences between domains that prevent direct method transfers between prokaryotic and eukaryotic soil metabarcoding approaches, currently dominated by short-read sequencing. These include the existence of divergent diversity concepts and the variations in eukaryotic morphology that affect sampling and DNA extraction. Furthermore, eukaryotes experienced much more variable evolutionary rates than prokaryotes, which prevent capturing the entire eukaryotic diversity in a soil with a single amplification protocol fit for short-read sequencing. In the final part we focus on future potentials for optimization of eukaryotic metabarcoding that include superior possibility of functionally characterizing eukaryotes and to extend the current information obtained, such as by adding a real quantitative component. This review should optimize future metabarcoding approaches targeting soil eukaryotes and kickstart this promising research direction.
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Affiliation(s)
- Enrique Lara
- Real Jardín Botánico‐CSIC, Plaza de Murillo 2Madrid28014Spain
| | - David Singer
- UMR CNRS 6112 LPG‐BIAFAngers University, 2 Boulevard LavoisierAngers49045France
| | - Stefan Geisen
- Laboratory of NematologyWageningen UniversityWageningen6700 AAThe Netherlands
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Bateman KS, Stentiford GD, Kerr R, Hooper C, White P, Edwards M, Ross S, Hazelgrove R, Daumich C, Green MJ, Ivory D, Evans C, Bass D. Amoebic crab disease (ACD) in edible crab Cancer pagurus from the English Channel, UK. DISEASES OF AQUATIC ORGANISMS 2022; 150:1-16. [PMID: 35796507 DOI: 10.3354/dao03668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The genera Paramoeba and Neoparamoeba (Amoebozoa, Dactylopodida, Paramoebidae) include well-known opportunistic pathogens associated with fish (N. peruans; amoebic gill disease), lobsters, molluscs and sea urchins, but only rarely with crabs (grey crab disease of blue crabs). Following reports of elevated post-capture mortality in edible crabs Cancer pagurus captured from a site within the English Channel fishery in the UK, a novel disease (amoebic crab disease, ACD) was detected in significant proportions of the catch. We present histopathological, transmission electron microscopy and molecular phylogenetic data, showing that this disease is defined by colonization of haemolymph, connective tissues and fixed phagocytes by amoeboid cells, leading to tissue destruction and presumably death in severely diseased hosts. The pathology was strongly associated with a novel amoeba with a phylogenetic position on 18S rRNA gene trees robustly sister to Janickina pigmentifera (which groups within the current circumscription of Paramoeba/Neoparamoeba), herein described as Janickina feisti n. sp. We provide evidence that J. feisti is associated with ACD in 50% of C. pagurus sampled from the mortality event. A diversity of other paramoebid sequence types, clustering with known radiations of N. pemaquidensis and N. aestuarina and a novel N. aestuarina sequence type, was detected by PCR in most of the crabs investigated, but their detection was much less strongly associated with clinical signs of disease. The discovery of ACD in edible crabs from the UK is discussed relative to published historical health surveys for this species.
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Affiliation(s)
- K S Bateman
- International Centre of Excellence for Aquatic Animal Health, Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth DT4 8UB, UK
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10
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Skujina I, Hooper C, Bass D, Feist SW, Bateman KS, Villalba A, Carballal MJ, Iglesias D, Cao A, Ward GM, Ryder DRG, Bignell JP, Kerr R, Ross S, Hazelgrove R, Macarie NA, Prentice M, King N, Thorpe J, Malham SK, McKeown NJ, Ironside JE. Discovery of the parasite Marteilia cocosarum sp. nov. In common cockle (Cerastoderma edule) fisheries in Wales, UK and its comparison with Marteilia cochillia. J Invertebr Pathol 2022; 192:107786. [PMID: 35700790 DOI: 10.1016/j.jip.2022.107786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/05/2022] [Accepted: 06/08/2022] [Indexed: 12/01/2022]
Abstract
Diseases of bivalve molluscs caused by paramyxid parasites of the genus Marteilia have been linked to mass mortalities and the collapse of commercially important shellfish populations. Until recently, no Marteilia spp. have been detected in common cockle (Cerastoderma edule) populations in the British Isles. Molecular screening of cockles from ten sites on the Welsh coast indicates that a Marteilia parasite is widespread in Welsh C. edule populations, including major fisheries. Phylogenetic analysis of ribosomal DNA (rDNA) gene sequences from this parasite indicates that it is a closely related but different species to Marteilia cochillia, a parasite linked to mass mortality of C. edule fisheries in Spain, and that both are related to Marteilia octospora, for which we provide new rDNA sequence data. Preliminary light and transmission electron microscope (TEM) observations support this conclusion, indicating that the parasite from Wales is located primarily within areas of inflammation in the gills and the connective tissue of the digestive gland, whereas M. cochillia is found mainly within the epithelium of the digestive gland. The impact of infection by the new species, here described as Marteilia cocosarum n. sp., upon Welsh fisheries is currently unknown.
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Affiliation(s)
- Ilze Skujina
- Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, UK
| | - Chantelle Hooper
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK
| | - David Bass
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK; Sustainable Aquaculture Futures, Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter UK; Department of Life Sciences, Natural History Museum, London, UK
| | - Stephen W Feist
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK
| | - Kelly S Bateman
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK
| | - Antonio Villalba
- Centro de Investigacións Mariñas, Vilanova de Arousa, Spain; Departamento de Ciencias de la Vida, Universdad de Alcalá, Alcalá de Henares, Spain; Research Centre for Experimental Marine Biology and Biotechnology, University of the Basque Country, Plentzia, Spain
| | | | - David Iglesias
- Centro de Investigacións Mariñas, Vilanova de Arousa, Spain
| | - Asunción Cao
- Centro de Investigacións Mariñas, Vilanova de Arousa, Spain
| | - Georgia M Ward
- Department of Life Sciences, Natural History Museum, London, UK
| | - David R G Ryder
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK
| | - John P Bignell
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK
| | - Rose Kerr
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK
| | - Stuart Ross
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK
| | - Richard Hazelgrove
- International Centre of Excellence for Aquatic Animal Health, The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK
| | - Nicolae A Macarie
- Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, UK
| | - Melanie Prentice
- Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, UK
| | - Nathan King
- School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, UK
| | - Jamie Thorpe
- School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, UK
| | - Shelagh K Malham
- School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, UK
| | - Niall J McKeown
- Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, UK
| | - Joseph E Ironside
- Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, UK.
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11
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Diggles BK, Bass D, Bateman KS, Chong R, Daumich C, Hawkins KA, Hazelgrove R, Kerr R, Moody NJG, Ross S, Stentiford GD. Haplosporidium acetes n. sp. infecting the hepatopancreas of jelly prawns Acetes sibogae australis from Moreton Bay, Australia. J Invertebr Pathol 2022; 190:107751. [DOI: 10.1016/j.jip.2022.107751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 11/29/2022]
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12
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Davies CE, Thomas JE, Malkin SH, Batista FM, Rowley AF, Coates CJ. Hematodinium sp. infection does not drive collateral disease contraction in a crustacean host. eLife 2022; 11:70356. [PMID: 35179494 PMCID: PMC8856654 DOI: 10.7554/elife.70356] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 02/08/2022] [Indexed: 01/10/2023] Open
Abstract
Host, pathogen, and environment are determinants of the disease triangle, the latter being a key driver of disease outcomes and persistence within a community. The dinoflagellate genus Hematodinium is detrimental to crustaceans globally - considered to suppress the innate defences of hosts, making them more susceptible to co-infections. Evidence supporting immune suppression is largely anecdotal and sourced from diffuse accounts of compromised decapods. We used a population of shore crabs (Carcinus maenas), where Hematodinium sp. is endemic, to determine the extent of collateral infections across two distinct environments (open-water, semi-closed dock). Using a multi-resource approach (PCR, histology, haematology, population genetics, eDNA), we identified 162 Hematodinium-positive crabs and size/sex-matched these to 162 Hematodinium-free crabs out of 1191 analysed. Crabs were interrogated for known additional disease-causing agents; haplosporidians, microsporidians, mikrocytids, Vibrio spp., fungi, Sacculina, trematodes, and haemolymph bacterial loads. We found no significant differences in occurrence, severity, or composition of collateral infections between Hematodinium-positive and Hematodinium-free crabs at either site, but crucially, we recorded site-restricted blends of pathogens. We found no gross signs of host cell immune reactivity towards Hematodinium in the presence or absence of other pathogens. We contend Hematodinium sp. is not the proximal driver of co-infections in shore crabs, which suggests an evolutionary drive towards latency in this environmentally plastic host.
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Affiliation(s)
- Charlotte E Davies
- Department of Biosciences, College of Science, Swansea University, Swansea, United Kingdom
| | - Jessica E Thomas
- Department of Biosciences, College of Science, Swansea University, Swansea, United Kingdom
| | - Sophie H Malkin
- Department of Biosciences, College of Science, Swansea University, Swansea, United Kingdom
| | - Frederico M Batista
- Department of Biosciences, College of Science, Swansea University, Swansea, United Kingdom.,Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth, United Kingdom
| | - Andrew F Rowley
- Department of Biosciences, College of Science, Swansea University, Swansea, United Kingdom
| | - Christopher J Coates
- Department of Biosciences, College of Science, Swansea University, Swansea, United Kingdom
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13
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Briscoe AG, Nichols S, Hartikainen H, Knipe H, Foster R, Green AJ, Okamura B, Bass D. High-Throughput Sequencing of faeces provides evidence for dispersal of parasites and pathogens by migratory waterbirds. Mol Ecol Resour 2021; 22:1303-1318. [PMID: 34758191 DOI: 10.1111/1755-0998.13548] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 10/26/2021] [Accepted: 11/02/2021] [Indexed: 11/28/2022]
Abstract
Examination of faecal material has demonstrated how a broad range of organisms are distributed by bird movements. Such research has largely focused on dispersal of plant seeds by frugivores and of freshwater organisms by waterbirds. However, with few exceptions (e.g. avian influenza, Ebola virus), there is a dearth of evidence for transport of parasites and pathogens. High-throughput sequencing methods now provide a powerful means of addressing this knowledge gap by elucidating faecal contents in unprecedented detail. We collected faeces excreted by a range of migratory waterbirds in south-west Spain and pooled faecal DNA to create libraries reflective of feeding behavior. We created sets of libraries using high-throughput metagenomic and amplicon sequencing. For the latter we employed two sets of primers to broadly target the V4 region of the 18S rRNA gene (one set amplifying the region across all eukaryotes, the other excluding amplification of metazoans). Libraries revealed a wide diversity of eukaryotes, including parasites of the faecal producers themselves, parasites of food items, or those incidentally ingested. We also detected novel microbial eukaryotic taxa and found that parasite assemblage profiles were relatively distinct. Comparing the performance of the methods used supports their joint use for future studies of diversity and abundance. Because viable stages of many parasites are likely to be present in faeces, our results suggest significant levels of bird-mediated dispersal of parasites (both from avian and other hosts). Our methods revealed much hidden biodiversity, and allowed identification of the individuals who produced the faecal samples to species level, facilitating the study of interaction networks.
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Affiliation(s)
- Andrew G Briscoe
- Department of Life Sciences, Natural History Museum, London, United Kingdom.,Core Research Laboratories, Natural History Museum, London, United Kingdom
| | - Sarah Nichols
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Hanna Hartikainen
- Department of Life Sciences, Natural History Museum, London, United Kingdom.,Eawag and Institute for Integrative Biology, Eidgenössische Technische Hochschule (ETH), Zurich, Switzerland
| | - Hazel Knipe
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Rachel Foster
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Andy J Green
- Department of Wetland Ecology, Estación Biológica de Doñana, EBD-CSIC, 41092, Sevilla, Spain
| | - Beth Okamura
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - David Bass
- Department of Life Sciences, Natural History Museum, London, United Kingdom.,Centre for Environment, Aquaculture and Fisheries Science (Cefas), Weymouth, UK
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14
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Bass D, Rueckert S, Stern R, Cleary AC, Taylor JD, Ward GM, Huys R. Parasites, pathogens, and other symbionts of copepods. Trends Parasitol 2021; 37:875-889. [PMID: 34158247 DOI: 10.1016/j.pt.2021.05.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/03/2021] [Accepted: 05/17/2021] [Indexed: 12/20/2022]
Abstract
There is a large diversity of eukaryotic symbionts of copepods, dominated by epizootic protists such as ciliates, and metazoan parasites. Eukaryotic endoparasites, copepod-associated bacteria, and viruses are less well known, partly due to technical limitations. However, new molecular techniques, combined with a range of other approaches, provide a complementary toolkit for understanding the complete symbiome of copepods and how the symbiome relates to their ecological roles, relationships with other biota, and responses to environmental change. In this review we provide the most complete overview of the copepod symbiome to date, including microeukaryotes, metazoan parasites, bacteria, and viruses, and provide extensive literature databases to inform future studies.
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Affiliation(s)
- David Bass
- International Centre of Excellence in Aquatic Animal Health, Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, UK; Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK; Sustainable Aquaculture Futures, Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
| | - Sonja Rueckert
- School of Applied Sciences, Edinburgh Napier University, Sighthill Court, Edinburgh EH11 4BN, UK
| | - Rowena Stern
- Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Alison C Cleary
- Department of Natural Sciences, University of Agder, Universitetsveien 25, Kristiansand, 4630, Norway
| | - Joe D Taylor
- School of Chemistry and Bioscience, University of Bradford, Richmond Rd, Bradford BD7 1DP, UK
| | - Georgia M Ward
- International Centre of Excellence in Aquatic Animal Health, Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, UK; Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Rony Huys
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
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15
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Polinski MP, Laurin E, Delphino MKVC, Lowe GJ, Meyer GR, Abbott CL. Evaluation of histopathology, PCR, and qPCR to detect Mikrocytos mackini in oysters Crassostrea gigas using Bayesian latent class analysis. DISEASES OF AQUATIC ORGANISMS 2021; 144:21-31. [PMID: 33704089 DOI: 10.3354/dao03566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Latent class analysis (LCA) is a common method to evaluate the diagnostic sensitivity (DSe) and specificity (DSp) for pathogen detection assays in the absence of a perfect reference standard. Here we used LCA to evaluate the diagnostic accuracy of 3 tests for the detection of Mikrocytos mackini in Pacific oysters Crassostrea gigas: conventional polymerase chain reaction (PCR), real-time quantitative PCR (qPCR), and histopathology. A total of 802 Pacific oysters collected over 12 sampling events from 9 locations were assessed. Preliminary investigations indicated that standard LCA assumptions of test independence and constant detection accuracy across locations were likely unrealistic. This was mitigated by restructuring the LCA in a Bayesian framework to include test-derived knowledge about pathogen prevalence and load for categorizing populations into 2 classes of infection severity (low or high) and assessing separate DSe and DSp estimates for each class. Median DSp estimates were high (>96%) for all 3 tests in both population classes. DSe estimates varied between tests and population classes but were consistently highest for qPCR (87-99%) and lowest for histopathology (21-51%). Acknowledging that detection of M. mackini may be fitted to multiple diagnostic and management purposes, qPCR had the highest DSe while maintaining similar DSp to both conventional PCR and histopathology and thus is generally well-suited to most applications.
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Affiliation(s)
- Mark P Polinski
- Department of Fisheries and Oceans, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, BC V9T 6N7, Canada
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16
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Hittorf M, Letsch-Praxmarer S, Windegger A, Bass D, Kirchmair M, Neuhauser S. Revised Taxonomy and Expanded Biodiversity of the Phytomyxea (Rhizaria, Endomyxa). J Eukaryot Microbiol 2020; 67:648-659. [PMID: 32654223 PMCID: PMC7756720 DOI: 10.1111/jeu.12817] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 05/21/2020] [Accepted: 06/25/2020] [Indexed: 12/27/2022]
Abstract
Phytomyxea (phytomyxids) is a group of obligate biotrophic pathogens belonging to the Rhizaria. Some phytomyxids are well studied and include known plant pathogens such as Plasmodiophora brassicae, the causal agent of clubroot disease. Despite this economic importance, the taxonomy and biodiversity of this group are largely cryptic, with many species described in the premolecular area. Some of these species were key for establishing the morphotaxonomic concepts that define most genera to this day, but systematic efforts to include and integrate those species into molecular studies are still lacking. The aim of this study was to expand our understanding of phytomyxid biodiversity in terrestrial environments. Thirty-eight environmental samples from habitats in which novel and known diversity of Phytomyxea was expected were analysed. We were able to generate 18S rRNA sequences from Ligniera verrucosa, a species which is well defined based on ultrastructure. Phylogenetic analyses of the collected sequences rendered the genera Lignera, Plasmodiophora and Spongospora polyphyletic, and identified two novel and apparently diverse lineages (clade 17, clade 18). Based on these findings and on data from previous studies, we formally establish the new genera Pseudoligniera n. gen. for L. verrucosa,Hillenburgia n. gen. for Spongospora nasturtii and revert Plasmodiophora diplantherae to its original name Ostenfeldiella diplantherae.
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Affiliation(s)
- Michaela Hittorf
- Institute of Microbiology, University of Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
| | | | - Alexandra Windegger
- Institute of Microbiology, University of Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
| | - David Bass
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, United Kingdom.,Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, DT4 8UB, United Kingdom
| | - Martin Kirchmair
- Institute of Microbiology, University of Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
| | - Sigrid Neuhauser
- Institute of Microbiology, University of Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
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17
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Haplosporosomes, sporoplasmosomes and their putative taxonomic relationships in rhizarians and myxozoans. Parasitology 2020; 147:1614-1628. [PMID: 32943127 DOI: 10.1017/s0031182020001717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This paper reviews current knowledge of the structure, genesis, cytochemistry and putative functions of the haplosporosomes of haplosporidians (Urosporidium, Haplosporidium, Bonamia, Minchinia) and paramyxids (Paramyxa, Paramyxoides, Marteilia, Marteilioides, Paramarteilia), and the sporoplasmosomes of myxozoans (Myxozoa - Malacosporea, Myxosporea). In all 3 groups, these bodies occur in plasmodial trophic stages, disappear at the onset of sporogony, and reappear in the spore. Some haplosporidian haplosporosomes lack the internal membrane regarded as characteristic of these bodies and that phylum. Haplosporidian haplosporogenesis is through the Golgi (spherulosome in the spore), either to form haplosporosomes at the trans-Golgi network, or for the Golgi to produce formative bodies from which membranous vesicles bud, thus acquiring the external membrane. The former method also forms sporoplasmosomes in malacosporeans, while the latter is the common method of haplosporogenesis in paramyxids. Sporoplasmogenesis in myxosporeans is largely unknown. The haplosporosomes of Haplosporidium nelsoni and sporoplasmosomes of malacosporeans are similar in arraying themselves beneath the plasmodial plasma membrane with their internal membranes pointing to the exterior, possibly to secrete their contents to lyse host cells or repel haemocytes. It is concluded that these bodies are probably multifunctional within and between groups, their internal membranes separating different functional compartments, and their origin may be from common ancestors in the Neoproterozoic.
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18
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Darriba S, Lee RS, López C. Mikrocytos mytilicoli n.sp. (Cercozoa, Mikrocytida, Mikrocytiidae) infecting the copepod Mytilicola intestinalis (Arthropoda, Cyclopoida, Mytilicolidae), a symbiont of Mytilus galloprovincialis in Galicia (NW Spain). J Invertebr Pathol 2020; 176:107460. [PMID: 32891682 DOI: 10.1016/j.jip.2020.107460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/28/2020] [Accepted: 08/29/2020] [Indexed: 10/23/2022]
Abstract
During a histopathological survey of Mytilus galloprovincialis in Galicia (NW Spain), microcells were observed infecting several organs of the symbiont copepod Mytilicola intestinalis. Positive results of PCR assay with specific primers for genus Mikrocytos and a clear signal of in situ hybridization with MACKINI-1 digoxigenin- labelled DNA probe (DIG-ISH) indicated a protozoan parasite of Mikrocytos genus. The ultrastructural study revealed intra and extracellular locations, polymorphic nuclei, intracellular round vesicles in the cytoplasm and absence of mitochondria. The present paper reports the characterization of the Mikrocytos sp. infecting M. intestinalis and proposes a novel species in the genus: Mikrocytos mytilicoli n. sp. A sequence of 18S-28S rDNA was obtained with 95.6% maximum identity (query cover 100%) with Mikrocytos mackini. Phylogenetic analysis showed that M. mytilicoli n. sp. and M. mackini share a common ancestor. However, comparison of the ITS1 rDNA region showed low similarity (75.8%) with M. mackini, which, combined with differences in ultrastructural details, host and geographic location, support the designation of a new species. This is the first description of a microcytid parasite of the genus Mikrocytos from a non-bivalve host.
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Affiliation(s)
- Susana Darriba
- Instituto Tecnolóxico para o Control do Medio Mariño de Galicia (INTECMAR), Consellería do Mar, Xunta de Galicia, Peirao de Vilaxoán s/n, 36611 Vilagarcía de, Arousa, Pontevedra, Spain
| | - Ren-Shiang Lee
- Departamento I+D+i, Consello Regulador do Mexillón de Galicia, Avda da Mariña, 25, 36600 Vilagarcía de Arousa, Pontevedra, Spain
| | - Carmen López
- Centro de Investigacións Mariñas (CIMA), Consellería do Mar, Xunta de Galícia, Pedras de Corón s/n, 36620 Vilanova de Arousa, Pontevedra, Spain.
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19
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Abstract
Developing a detailed understanding of how all known forms of life are related to one another in the tree of life has been a major preoccupation of biology since the idea of tree-like evolution first took hold. Since most life is microbial, our intuitive use of morphological comparisons to infer relatedness only goes so far, and molecular sequence data, most recently from genomes and transcriptomes, has been the primary means to infer these relationships. For prokaryotes this presented new challenges, since the degree of horizontal gene transfer led some to question the tree-like depiction of evolution altogether. Most eukaryotes are also microbial, but in contrast to prokaryotic life, the application of large-scale molecular data to the tree of eukaryotes has largely been a constructive process, leading to a small number of very diverse lineages, or 'supergroups'. The tree is not completely resolved, and contentious problems remain, but many well-established supergroups now encompass much more diversity than the traditional kingdoms. Some of the most exciting recent developments come from the discovery of branches in the tree that we previously had no inkling even existed, many of which are of great ecological or evolutionary interest. These new branches highlight the need for more exploration, by high-throughput molecular surveys, but also more traditional means of observations and cultivation.
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Affiliation(s)
- Patrick J Keeling
- Department of Botany, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada.
| | - Fabien Burki
- Department of Organismal Biology, Program in Systematic Biology, Uppsala University, Uppsala, Sweden; Science for Life Laboratory, Uppsala University, Uppsala, Sweden
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20
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Bass D, Del Campo J. Microeukaryotes in animal and plant microbiomes: Ecologies of disease? Eur J Protistol 2020; 76:125719. [PMID: 32736314 DOI: 10.1016/j.ejop.2020.125719] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/28/2020] [Accepted: 05/25/2020] [Indexed: 02/06/2023]
Abstract
Studies of animal and plant microbiomes are burgeoning, but the majority of these focus on bacteria and rarely include microeukaryotes other than fungi. However, there is growing evidence that microeukaryotes living on and in larger organisms (e.g. plants, animals, macroalgae) are diverse and in many cases abundant. We present here a new combination of 'anti-metazoan' primers: 574*f-UNonMet_DB that amplify a wide diversity of microeukaryotes including some groups that are difficult to amplify using other primer combinations. While many groups of microeukaryotic parasites are recognised, myriad other microeukaryotes are associated with hosts as previously unknown parasites (often genetically divergent so difficult to amplify using standard PCR primers), opportunistic parasites, commensals, and other ecto- and endo-symbionts, across the 'symbiotic continuum'. These fulfil a wide range of roles from pathogenesis to mutually beneficial symbioses, but mostly their roles are unknown and likely fall somewhere along this spectrum, with the potential to switch the nature of their interactions with the host under different conditions. The composition and dynamics of host-associated microbial communities are also increasingly recognised as important moderators of host health. This 'pathobiome' approach to understanding disease is beginning to supercede a one-pathogen-one-disease paradigm, which cannot sufficiently explain many disease scenarios.
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Affiliation(s)
- David Bass
- Centre for Environment, Aquaculture and Fisheries Science (Cefas), Barrack Road, Weymouth, Dorset DT4 8UB, UK; Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK; Sustainable Aquaculture Futures, University of Exeter, Exeter EX4 4QD, UK; Biosciences, University of Exeter, Stocker Road, Exeter EX4 4HB, UK.
| | - Javier Del Campo
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
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21
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Edwards M, Coates CJ, Rowley AF. Host Range of the Mikrocytid Parasite Paramikrocytos canceri in Decapod Crustaceans. Pathogens 2019; 8:pathogens8040252. [PMID: 31756946 PMCID: PMC6963538 DOI: 10.3390/pathogens8040252] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/13/2019] [Accepted: 11/19/2019] [Indexed: 11/16/2022] Open
Abstract
Mikrocytids are a widespread but rather neglected group of parasites of aquatic invertebrates. One such parasite is Paramikrocytos canceri—discovered to infect the antennal gland of the juvenile edible crab, Cancer pagurus, taken from several intertidal sites across the United Kingdom. To determine if this parasite is also present in other species of decapod crustaceans, we surveyed crabs (n = 330) across two contrasting sites in Pembrokeshire (UK). Using a histopathological approach, P. canceri infection was confirmed in variable numbers of edible crabs from both survey sites, 7–44%. No measurable signs of infection were encountered in four other co-located species, including European shore crabs (Carcinus maenas), Montagu’s crabs (Xantho hydrophilus), velvet swimming crabs (Necora puber) and broad-clawed porcelain crabs (Porcellana platycheles). These data imply that P. canceri has a more limited host range than suggested by molecular diagnosis alone.
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22
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Bass D, Stentiford GD, Wang HC, Koskella B, Tyler CR. The Pathobiome in Animal and Plant Diseases. Trends Ecol Evol 2019; 34:996-1008. [PMID: 31522755 DOI: 10.1016/j.tree.2019.07.012] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 07/14/2019] [Accepted: 07/23/2019] [Indexed: 12/11/2022]
Abstract
A growing awareness of the diversity and ubiquity of microbes (eukaryotes, prokaryotes, and viruses) associated with larger 'host' organisms has led to the realisation that many diseases thought to be caused by one primary agent are the result of interactions between multiple taxa and the host. Even where a primary agent can be identified, its effect is often moderated by other symbionts. Therefore, the one pathogen-one disease paradigm is shifting towards the pathobiome concept, integrating the interaction of multiple symbionts, host, and environment in a new understanding of disease aetiology. Taxonomically, pathobiomes are variable across host species, ecology, tissue type, and time. Therefore, a more functionally driven understanding of pathobiotic systems is necessary, based on gene expression, metabolic interactions, and ecological processes.
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Affiliation(s)
- David Bass
- Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Barrack Road, The Nothe, Weymouth, DT4 8UB, UK; Sustainable Aquaculture Futures, University of Exeter, Exeter, EX4 4QD, UK; Department of Life Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK.
| | - Grant D Stentiford
- Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Barrack Road, The Nothe, Weymouth, DT4 8UB, UK; Sustainable Aquaculture Futures, University of Exeter, Exeter, EX4 4QD, UK
| | - Han-Ching Wang
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, 70101, Taiwan; International Center for Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Britt Koskella
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Charles R Tyler
- Sustainable Aquaculture Futures, University of Exeter, Exeter, EX4 4QD, UK; Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4HB, UK
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23
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Ward GM, Feist SW, Noguera P, Marcos-López M, Ross S, Green M, Urrutia A, Bass D. Detection and characterisation of haplosporidian parasites of the blue mussel Mytilus edulis, including description of the novel parasite Minchinia mytili n. sp. DISEASES OF AQUATIC ORGANISMS 2019; 133:57-68. [PMID: 31089003 DOI: 10.3354/dao03326] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The edible mussel Mytilus edulis is a major aquaculture commodity in Europe, with 168000 t produced in 2015. A number of abundant, well characterised parasites of the species are known, though none are considered to cause significant mortality. Haplosporida (Rhizaria, Endomyxa) is an order of protistan parasites of aquatic invertebrates, the best studied of which are the oyster pathogens Haplosporidium nelsoni and Bonamia ostreae. While these species are well characterised within their hosts, the diversity, life-cycle and modes of transmission of haplosporidians are very poorly understood. Haplosporidian parasites have previously been reported from Mytilus spp., however the majority of these remain uncharacterised, and no molecular data exist for any species. In this study, we identified 2 novel haplosporidian parasites of M. edulis present in the UK. The first of these, observed by light microscopy and in situ hybridisation infecting the gills, mantle, gonadal tubules and digestive connective tissues of mussels in the Tamar estuary, England, we describe as Minchinia mytili on the basis of 18S sequence data. The second, observed infecting a single archive specimen collected in Loch Spelve, Mull, Scotland, infects the foot muscle, gills and connective tissue of the digestive gland. Sequence data places this parasite in an uncharacterised clade of sequences amplified from tropical bivalve guts and water samples, sister to H. nelsoni. Screening of water and sediment samples collected at the sample site in the Tamar estuary revealed the presence of both sequence types in the water column, suggesting host-free or planktonic life stages.
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Affiliation(s)
- Georgia M Ward
- Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
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Cavalier-Smith T, Chao EE, Lewis R. Multigene phylogeny and cell evolution of chromist infrakingdom Rhizaria: contrasting cell organisation of sister phyla Cercozoa and Retaria. PROTOPLASMA 2018; 255:1517-1574. [PMID: 29666938 PMCID: PMC6133090 DOI: 10.1007/s00709-018-1241-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/12/2018] [Indexed: 05/18/2023]
Abstract
Infrakingdom Rhizaria is one of four major subgroups with distinct cell body plans that comprise eukaryotic kingdom Chromista. Unlike other chromists, Rhizaria are mostly heterotrophic flagellates, amoebae or amoeboflagellates, commonly with reticulose (net-like) or filose (thread-like) feeding pseudopodia; uniquely for eukaryotes, cilia have proximal ciliary transition-zone hub-lattices. They comprise predominantly flagellate phylum Cercozoa and reticulopodial phylum Retaria, whose exact phylogenetic relationship has been uncertain. Given even less clear relationships amongst cercozoan classes, we sequenced partial transcriptomes of seven Cercozoa representing five classes and endomyxan retarian Filoreta marina to establish 187-gene multiprotein phylogenies. Ectoreta (retarian infraphyla Foraminifera, Radiozoa) branch within classical Cercozoa as sister to reticulose Endomyxa. This supports recent transfer of subphylum Endomyxa from Cercozoa to Retaria alongside subphylum Ectoreta which embraces classical retarians where capsules or tests subdivide cells into organelle-containing endoplasm and anastomosing pseudopodial net-like ectoplasm. Cercozoa are more homogeneously filose, often with filose pseudopodia and/or posterior ciliary gliding motility: zooflagellate Helkesimastix and amoeboid Guttulinopsis form a strongly supported clade, order Helkesida. Cercomonads are polyphyletic (Cercomonadida sister to glissomonads; Paracercomonadida deeper). Thecofilosea are a clade, whereas Imbricatea may not be; Sarcomonadea may be paraphyletic. Helkesea and Metromonadea are successively deeper outgroups within cercozoan subphylum Monadofilosa; subphylum Reticulofilosa (paraphyletic on site-heterogeneous trees) branches earliest, Granofilosea before Chlorarachnea. Our multiprotein trees confirm that Rhizaria are sisters of infrakingdom Halvaria (Alveolata, Heterokonta) within chromist subkingdom Harosa (= SAR); they further support holophyly of chromist subkingdom Hacrobia, and are consistent with holophyly of Chromista as sister of kingdom Plantae. Site-heterogeneous rDNA trees group Kraken with environmental DNA clade 'eSarcomonad', not Paracercomonadida. Ectoretan fossil dates evidence ultrarapid episodic stem sequence evolution. We discuss early rhizarian cell evolution and multigene tree coevolutionary patterns, gene-paralogue evidence for chromist monophyly, and integrate this with fossil evidence for the age of Rhizaria and eukaryote cells, and revise rhizarian classification.
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Affiliation(s)
| | - Ema E Chao
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - Rhodri Lewis
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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Bass D, Tikhonenkov DV, Foster R, Dyal P, Janouškovec J, Keeling PJ, Gardner M, Neuhauser S, Hartikainen H, Mylnikov AP, Berney C. Rhizarian 'Novel Clade 10' Revealed as Abundant and Diverse Planktonic and Terrestrial Flagellates, including Aquavolon n. gen. J Eukaryot Microbiol 2018; 65:828-842. [PMID: 29658156 PMCID: PMC6282753 DOI: 10.1111/jeu.12524] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/19/2018] [Accepted: 03/28/2018] [Indexed: 01/03/2023]
Abstract
Rhizarian ‘Novel Clade 10’ (NC10) is frequently detected by 18S rRNA gene sequencing studies in freshwater planktonic samples. We describe a new genus and two species of eukaryovorous biflagellate protists, Aquavolon hoantrani n. gen. n. sp. and A. dientrani n. gen. n. sp., which represent the first morphologically characterized members of NC10, here named Aquavolonida ord. nov. The slightly metabolic cells possess naked heterodynamic flagella, whose kinetosomes lie at a right angle to each other and are connected by at least one fibril. Unlike their closest known relative Tremula longifila, they rotate around their longitudinal axis when swimming and only very rarely glide on surfaces. Screening of a wide range of environmental DNA extractions with lineage‐specific PCR primers reveals that Aquavolonida consists of a large radiation of protists, which are most diversified in freshwater planktonic habitats and as yet undetected in marine environments. Earlier‐branching lineages in Aquavolonida include less frequently detected organisms from soils and freshwater sediments. The 18S rRNA gene phylogeny suggests that Aquavolonida forms a common evolutionary lineage with tremulids and uncharacterized ‘Novel Clade 12’, which likely represents one of the deepest lineages in the Rhizaria, separate from Cercozoa (Filosa), Endomyxa, and Retaria.
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Affiliation(s)
- David Bass
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK.,Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, DT4 8UB, UK
| | - Denis Victorovich Tikhonenkov
- Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, 152742, Russia.,Botany Department, University of British Columbia, Vancouver, BC, V6T1Z4, Canada
| | - Rachel Foster
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Patricia Dyal
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Jan Janouškovec
- Botany Department, University of British Columbia, Vancouver, BC, V6T1Z4, Canada.,Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK
| | - Patrick J Keeling
- Botany Department, University of British Columbia, Vancouver, BC, V6T1Z4, Canada
| | - Michelle Gardner
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Sigrid Neuhauser
- Institute of Microbiology, University of Innsbruck, Technikerstraße 25, Innsbruck, 6020, Austria
| | - Hanna Hartikainen
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Alexandre P Mylnikov
- Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, 152742, Russia
| | - Cédric Berney
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK
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Ngo CN, Braithwaite KS, Bass D, Young AJ, Croft BJ. Phytocercomonas venanatans, a New Species of Cercozoa Associated with Chlorotic Streak of Sugarcane. PHYTOPATHOLOGY 2018; 108:479-486. [PMID: 29256830 DOI: 10.1094/phyto-07-17-0237-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chlorotic streak is a global disease of commercial sugarcane (Saccharum spp. hybrids). The disease is transmitted by wet soil, water, as well as in diseased planting material. Although first recognized almost 90 years ago and despite significant research effort, the identity of the causal agent has been elusive. Metagenomic high throughput sequencing (HTS) facilitated the discovery of novel protistan ribosomal and nuclear genes in chlorotic streak-infected sugarcane. These sequences suggest a possible causal agent belonging to the order Cercomonadida (Rhizaria, phylum Cercozoa). An organism with morphological features similar to cercomonads (=Cercomonadida) was isolated into pure axenic culture from internal stalk tissues of infected sugarcane. The isolated organism contained DNA sequences identical to those identified in infected plants by HTS. The DNA sequences and the morphology of the organism did not match any known species. Here we present a new genus and species, Phytocercomonas venanatans, which is associated with chlorotic streak of sugarcane. Amplicon sequencing also supports that P. venanatans is associated with this disease. This is the first reported member from Cercomonadida showing a probable pathogenic association with higher plants.
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Affiliation(s)
- Chuong N Ngo
- First and second authors: Sugar Research Australia, Indooroopilly, QLD, 4068, Australia; third author: Division of Genomics and Microbial Diversity, Department of Life Sciences, Natural History Museum, London, SW7 5BD, United Kingdom and Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, United Kingdom; fourth author: Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, 4350, Australia; and fifth author: Sugar Research Australia, Woodford, QLD 4514, Australia
| | - Kathryn S Braithwaite
- First and second authors: Sugar Research Australia, Indooroopilly, QLD, 4068, Australia; third author: Division of Genomics and Microbial Diversity, Department of Life Sciences, Natural History Museum, London, SW7 5BD, United Kingdom and Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, United Kingdom; fourth author: Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, 4350, Australia; and fifth author: Sugar Research Australia, Woodford, QLD 4514, Australia
| | - David Bass
- First and second authors: Sugar Research Australia, Indooroopilly, QLD, 4068, Australia; third author: Division of Genomics and Microbial Diversity, Department of Life Sciences, Natural History Museum, London, SW7 5BD, United Kingdom and Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, United Kingdom; fourth author: Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, 4350, Australia; and fifth author: Sugar Research Australia, Woodford, QLD 4514, Australia
| | - Anthony J Young
- First and second authors: Sugar Research Australia, Indooroopilly, QLD, 4068, Australia; third author: Division of Genomics and Microbial Diversity, Department of Life Sciences, Natural History Museum, London, SW7 5BD, United Kingdom and Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, United Kingdom; fourth author: Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, 4350, Australia; and fifth author: Sugar Research Australia, Woodford, QLD 4514, Australia
| | - Barry J Croft
- First and second authors: Sugar Research Australia, Indooroopilly, QLD, 4068, Australia; third author: Division of Genomics and Microbial Diversity, Department of Life Sciences, Natural History Museum, London, SW7 5BD, United Kingdom and Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, United Kingdom; fourth author: Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, 4350, Australia; and fifth author: Sugar Research Australia, Woodford, QLD 4514, Australia
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Garcia C, Haond C, Chollet B, Nerac M, Omnes E, Joly JP, Dubreuil C, Serpin D, Langlade A, Le Gal D, Terre-Terrillon A, Courtois O, Guichard B, Arzul I. Descriptions of Mikrocytos veneroïdes n. sp. and Mikrocytos donaxi n. sp. (Ascetosporea: Mikrocytida: Mikrocytiidae), detected during important mortality events of the wedge clam Donax trunculus Linnaeus (Veneroida: Donacidae), in France between 2008 and 2011. Parasit Vectors 2018; 11:119. [PMID: 29499746 PMCID: PMC5834847 DOI: 10.1186/s13071-018-2692-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 02/01/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Microcell parasites are small intracellular protozoans mostly detected in molluscs and can be associated with mortalities. In 2010 and 2011, strong increases in mortality events were reported in different wild beds of the wedge clam Donax trunculus Linnaeus, along the Atlantic coast of France and the presence of potential pathogens, including microcells, was investigated. METHODS Clams collected in different beds showing mortality were examined by histology. Based on histological observations, confirmatory analyses were carried out, including transmission electron microscopy (TEM) and molecular characterization. RESULTS Histological analyses revealed the presence of small protozoans similar to microcell parasites in different tissues of Donax trunculus, particularly in muscular and connective tissues. TEM examination confirmed the intracellular localization of the protozoans. Moreover, the lack of haplosporosomes and mitochondria suggested that the observed parasites belong to the genus Mikrocytos Farley, Wolf & Elston, 1988. Mikrocytos genus-specific PCR and in situ hybridization results supported the microscopic observations. Sequence fragments of the 18S rRNA gene shared 75-83% identity with the different Mikrocytos spp. described previously, including Mikrocytos mackini Farley, Wolf & Elston, 1988 and M. boweri Abbott, Meyer, Lowe, Kim & Johnson, 2014. Phylogenetic analyses confirmed that the microcell parasites observed in Donax trunculus in France belong to the genus Mikrocytos and suggest the existence of two distinct species. CONCLUSIONS Based on morphological, ultrastructural, molecular data and host information, the two microcell parasites detected in Donax trunculus belong to the genus Mikrocytos and are distinct from previously described members of this genus. This is the first report of Mikrocytos spp. found in France and infecting the clam Donax trunculus. Mikrocytos veneroïdes n. sp. was detected in different wild beds and Mikrocytos donaxi n. sp. was detected only in Audierne Bay.
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Affiliation(s)
- Céline Garcia
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390 La Tremblade, France
| | - Christophe Haond
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390 La Tremblade, France
| | - Bruno Chollet
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390 La Tremblade, France
| | - Mirella Nerac
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390 La Tremblade, France
| | - Emmanuelle Omnes
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390 La Tremblade, France
| | - Jean-Pierre Joly
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390 La Tremblade, France
| | - Christine Dubreuil
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390 La Tremblade, France
| | - Delphine Serpin
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390 La Tremblade, France
| | - Aimé Langlade
- Ifremer, ODE-LITTORAL-LERMPL, Station de la Trinité sur Mer, 12, rue des Résistants, F-56470 La Trinité sur Mer, France
| | - Dominique Le Gal
- Ifremer, ODE-LITTORAL-LERBO, Station de Concarneau, Place de la Croix, F-29185 Concarneau, France
| | - Aouregan Terre-Terrillon
- Ifremer, ODE-LITTORAL-LERBO, Station de Concarneau, Place de la Croix, F-29185 Concarneau, France
| | - Olivier Courtois
- Ifremer, ODE-LITTORAL-LERPC, Station de La Tremblade, Avenue de Mus de Loup, F-17390 La Tremblade, France
| | - Benjamin Guichard
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390 La Tremblade, France
| | - Isabelle Arzul
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390 La Tremblade, France
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Ward GM, Neuhauser S, Groben R, Ciaghi S, Berney C, Romac S, Bass D. Environmental Sequencing Fills the Gap Between Parasitic Haplosporidians and Free-living Giant Amoebae. J Eukaryot Microbiol 2018; 65:574-586. [PMID: 29336517 PMCID: PMC6173291 DOI: 10.1111/jeu.12501] [Citation(s) in RCA: 18] [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: 07/21/2017] [Revised: 11/17/2017] [Accepted: 12/28/2017] [Indexed: 12/18/2022]
Abstract
Class Ascetosporea (Rhizaria; Endomyxa) comprises many parasites of invertebrates. Within this group, recent group-specific environmental DNA (eDNA) studies have contributed to the establishment of the new order Mikrocytida, a new phylogeny and characterization of Paramyxida, and illuminated the diversity and distribution of haplosporidians. Here, we use general and lineage-specific PCR primers to investigate the phylogenetic "gap" between haplosporidians and their closest known free-living relatives, the testate amoeba Gromia and reticulate amoeba Filoreta. Within this gap are Paradinium spp. parasites of copepods, which we show to be highly diverse and widely distributed in planktonic and benthic samples. We reveal a robustly supported radiation of parasites, ENDO-3, comprised of Paradinium and three further clades (ENDO-3a, ENDO-3b and SPP). A further environmental group, ENDO-2, perhaps comprising several clades, branches between this radiation and the free-living amoebae. Early diverging haplosporidians were also amplified, often associated with bivalves or deep-sea samples. The general primer approach amplified an overlapping set of novel lineages within ENDO-3 and Haplosporida, whereas the group-specific primer strategy, targeted to amplify from the earliest known divergent haplosporidians to Gromia, generated greater sequence diversity across part of this phylogenetic range.
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Affiliation(s)
- Georgia M. Ward
- Department of Life SciencesThe Natural History MuseumCromwell RoadLondonSW7 5BDUnited Kingdom
- CefasBarrack Road, The NotheWeymouthDorsetDT4 8UBUnited Kingdom
- College of Life and Environmental SciencesUniversity of ExeterStocker RoadExeterEX4 4QDUnited Kingdom
| | - Sigrid Neuhauser
- Institute of MicrobiologyUniversity of InnsbruckTechnikerstraßeInnsbruck25 6020Austria
| | - René Groben
- VÖR ‐ Marine Research Center at BreiðafjörðurNorðurtangiÓlafsvík355Iceland
- Present address:
Matís ohf.Vínlandsleið 12113ReykjavíkIceland
| | - Stefan Ciaghi
- Institute of MicrobiologyUniversity of InnsbruckTechnikerstraßeInnsbruck25 6020Austria
| | - Cédric Berney
- Sorbonne Universités UPMC Université Paris 06 & CNRSUMR7144Station Biologique de RoscoffPlace Georges TeissierRoscoff29680France
| | - Sarah Romac
- Sorbonne Universités UPMC Université Paris 06 & CNRSUMR7144Station Biologique de RoscoffPlace Georges TeissierRoscoff29680France
| | - David Bass
- Department of Life SciencesThe Natural History MuseumCromwell RoadLondonSW7 5BDUnited Kingdom
- CefasBarrack Road, The NotheWeymouthDorsetDT4 8UBUnited Kingdom
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Polinski MP, Meyer GR, Lowe GJ, Abbott CL. Seawater detection and biological assessments regarding transmission of the oyster parasite Mikrocytos mackini using qPCR. DISEASES OF AQUATIC ORGANISMS 2017; 126:143-153. [PMID: 29044044 DOI: 10.3354/dao03167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Mikrocytos mackini is an intracellular parasite of oysters and causative agent of Denman Island disease in Pacific oysters Crassostrea gigas. Although M. mackini has been investigated for decades, its natural mode of transmission, mechanism for host entry, and environmental stability are largely unknown. We explored these biological characteristics of M. mackini using a recently described quantitative PCR (qPCR) assay. We detected M. mackini in the flow-through tank water of experimentally infected oysters and during disease remission in host tissues following 6 wk of elevated water temperature. Waterborne exposure of oysters to M. mackini further confirmed the potential for extracellular seawater transmission of this parasite and also identified host gill to have the highest early and continued prevalence for M. mackini DNA compared to stomach, mantle, labial palps, or adductor muscle samples. However, infections following waterborne challenge were slow to develop despite a substantial exposure (>106 M. mackini l-1 for 24 h), and further investigation demonstrated that M. mackini occurrence and infectivity severely declined following extracellular seawater incubation of more than 24 h. This study demonstrates a potential for using qPCR to monitor M. mackini in wild or farmed oyster populations during periods of disease remission or from environmental seawater samples. This work also suggests that gill tissues may provide a primary site for waterborne entry and possibly shedding of M. mackini in oysters. Further, although extracellular seawater transmission of M. mackini was possible, poor environmental stability and infection efficiency likely restricts the geographic transmission of M. mackini between oysters in natural environs and may help to explain localized areas of infection.
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Affiliation(s)
- Mark P Polinski
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, BC V9T 6N7, Canada
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Freeman MA, Fuss J, Kristmundsson Á, Bjorbækmo MF, Mangot JF, del Campo J, Keeling PJ, Shalchian-Tabrizi K, Bass D. X-Cells Are Globally Distributed, Genetically Divergent Fish Parasites Related to Perkinsids and Dinoflagellates. Curr Biol 2017; 27:1645-1651.e3. [DOI: 10.1016/j.cub.2017.04.045] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 03/07/2017] [Accepted: 04/21/2017] [Indexed: 11/17/2022]
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Hartikainen H, Bass D, Briscoe AG, Knipe H, Green AJ, Okamura B. Assessing myxozoan presence and diversity using environmental DNA. Int J Parasitol 2016; 46:781-792. [DOI: 10.1016/j.ijpara.2016.07.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 07/07/2016] [Accepted: 07/08/2016] [Indexed: 02/04/2023]
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Hyperspora aquatica n.gn., n.sp. (Microsporidia), hyperparasitic in Marteilia cochillia (Paramyxida), is closely related to crustacean-infecting microspordian taxa. Parasitology 2016; 144:186-199. [PMID: 27748227 DOI: 10.1017/s0031182016001633] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The Paramyxida, closely related to haplosporidians, paradinids, and mikrocytids, is an obscure order of parasitic protists within the class Ascetosporea. All characterized ascetosporeans are parasites of invertebrate hosts, including molluscs, crustaceans and polychaetes. Representatives of the genus Marteilia are the best studied paramyxids, largely due to their impact on cultured oyster stocks, and their listing in international legislative frameworks. Although several examples of microsporidian hyperparasitism of paramyxids have been reported, phylogenetic data for these taxa are lacking. Recently, a microsporidian parasite was described infecting the paramyxid Marteilia cochillia, a serious pathogen of European cockles. In the current study, we investigated the phylogeny of the microsporidian hyperparasite infecting M. cochillia in cockles and, a further hyperparasite, Unikaryon legeri infecting the digenean Meiogymnophallus minutus, also in cockles. We show that rather than representing basally branching taxa in the increasingly replete Cryptomycota/Rozellomycota outgroup (containing taxa such as Mitosporidium and Paramicrosoridium), these hyperparasites instead group with other known microsporidian parasites infecting aquatic crustaceans. In doing so, we erect a new genus and species (Hyperspora aquatica n. gn., n.sp.) to contain the hyperparasite of M. cochillia and clarify the phylogenetic position of U. legeri. We propose that in both cases, hyperparasitism may provide a strategy for the vectoring of microsporidians between hosts of different trophic status (e.g. molluscs to crustaceans) within aquatic systems. In particular, we propose that the paramyxid hyperparasite H. aquatica may eventually be detected as a parasite of marine crustaceans. The potential route of transmission of the microsporidian between the paramyxid (in its host cockle) to crustaceans, and, the 'hitch-hiking' strategy employed by H. aquatica is discussed.
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A new phylogeny and environmental DNA insight into paramyxids: an increasingly important but enigmatic clade of protistan parasites of marine invertebrates. Int J Parasitol 2016; 46:605-19. [DOI: 10.1016/j.ijpara.2016.04.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 04/13/2016] [Accepted: 04/23/2016] [Indexed: 11/24/2022]
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Abstract
It is increasingly evident that cryptic stages of many parasites cause asymptomatic infections in a diversity of hosts. This review examines what may cause these infectious agents to persist as asymptomatic infections in invertebrates and how environmental change is linked with the subsequent development of overt infection and disease. In many systems, disease dynamics are closely associated with host condition which, in turn, is linked with environmental change. Symbionts (commensals and mutualists) display similar dynamics when environmental change causes them to exert negative effects on their hosts. Although such asymptomatic infections are demonstrated in a range of invertebrate hosts they are greatly undersampled because most invertebrate diseases are uninvestigated, infections are difficult to detect, and many parasite groups are poorly characterized. A better understanding of the diversity and distribution of parasites that cause asymptomatic infections and of their complex relationships with invertebrate hosts will enable a fuller appreciation of context-dependent host-parasite interactions and will address the biased focus on diseases of invertebrates of practical importance. The existence of such infections could underlie novel disease outbreaks that might otherwise be attributed to invasives while altered disease dynamics may provide an additional and complementary indicator of ecosystem change.
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Affiliation(s)
- Beth Okamura
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, United Kingdom
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Ramilo A, Pintado J, Villalba A, Abollo E. Perkinsus olseni and P. chesapeaki detected in a survey of perkinsosis of various clam species in Galicia (NW Spain) using PCR–DGGE as a screening tool. J Invertebr Pathol 2016; 133:50-8. [DOI: 10.1016/j.jip.2015.11.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 09/22/2015] [Accepted: 11/24/2015] [Indexed: 12/22/2022]
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37
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Sierra R, Cañas-Duarte SJ, Burki F, Schwelm A, Fogelqvist J, Dixelius C, González-García LN, Gile GH, Slamovits CH, Klopp C, Restrepo S, Arzul I, Pawlowski J. Evolutionary Origins of Rhizarian Parasites. Mol Biol Evol 2015; 33:980-3. [PMID: 26681153 DOI: 10.1093/molbev/msv340] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The SAR group (Stramenopila, Alveolata, Rhizaria) is one of the largest clades in the tree of eukaryotes and includes a great number of parasitic lineages. Rhizarian parasites are obligate and have devastating effects on commercially important plants and animals but despite this fact, our knowledge of their biology and evolution is limited. Here, we present rhizarian transcriptomes from all major parasitic lineages in order to elucidate their evolutionary relationships using a phylogenomic approach. Our results suggest that Ascetosporea, parasites of marine invertebrates, are sister to the novel clade Apofilosa. The phytomyxean plant parasites branch sister to the vampyrellid algal ectoparasites in the novel clade Phytorhiza. They also show that Ascetosporea + Apofilosa + Retaria + Filosa + Phytorhiza form a monophyletic clade, although the branching pattern within this clade is difficult to resolve and appears to be model-dependent. Our study does not support the monophyly of the rhizarian parasitic lineages (Endomyxa), suggesting independent origins for rhizarian animal and plant parasites.
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Affiliation(s)
- Roberto Sierra
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | | | - Fabien Burki
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Arne Schwelm
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Johan Fogelqvist
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Christina Dixelius
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Gillian H Gile
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Claudio H Slamovits
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Christophe Klopp
- L'Institute National De La Recherche Agronomique (INRA) GenoToul Bioinformatics Facility, Toulouse, France
| | - Silvia Restrepo
- Department of Biological Sciences, Universidad De Los Andes, Bogotá, Colombia
| | - Isabelle Arzul
- L'Institut Français De Recherche Pour L'exploitation De La Mer (Ifremer), La Tremblade, France
| | - Jan Pawlowski
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
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38
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Bass D, Stentiford GD, Littlewood D, Hartikainen H. Diverse Applications of Environmental DNA Methods in Parasitology. Trends Parasitol 2015; 31:499-513. [DOI: 10.1016/j.pt.2015.06.013] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/16/2015] [Accepted: 06/24/2015] [Indexed: 01/05/2023]
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39
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New perspective on the haplosporidian parasites of molluscs. J Invertebr Pathol 2015; 131:32-42. [DOI: 10.1016/j.jip.2015.07.014] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 07/24/2015] [Accepted: 07/27/2015] [Indexed: 11/24/2022]
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40
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41
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Thrupp TJ, Pope EC, Whitten MM, Bull JC, Wootton EC, Edwards M, Vogan CL, Rowley AF. Disease profiles of juvenile edible crabs (Cancer pagurus L.) differ at two geographically-close intertidal sites. J Invertebr Pathol 2015; 128:1-5. [DOI: 10.1016/j.jip.2015.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/07/2015] [Accepted: 04/11/2015] [Indexed: 11/25/2022]
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42
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Elston R, Friedman C, Gustafson L, Meyer G, Rogers R. Denman Island disease in Washington State, USA: distribution and prevalence in Pacific and Olympia oysters. DISEASES OF AQUATIC ORGANISMS 2015; 114:147-154. [PMID: 25993889 DOI: 10.3354/dao02862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We sampled over 2400 wild, feral, and cultured Pacific oysters Crassostrea gigas and Olympia oysters Ostrea lurida in Washington State, USA, from 2002 to 2006 to estimate the prevalence of infection with Mikrocytos mackini, the causative agent of Denman Island disease. Both histology and qualitative PCR methods were used. Estimates of true prevalence of M. mackini infection in C. gigas, after accounting for imperfect test sensitivity, ranged from mean values of 0 to 10.0% by histology and 0 to 8.4% based on pooled PCR samples. M. mackini was not detected in any of the O. lurida samples. Results suggest a lower prevalence of the pathogen and severity of this oyster disease in Washington than that indicated in previous reports from British Columbia, Canada, potentially attributable to higher seawater temperatures in the Washington sample locations.
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Affiliation(s)
- Ralph Elston
- AquaTechnics 455 W. Bell Street, Sequim, WA 98382, USA
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43
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Molecular detection of Mikrocytos mackini in Pacific oysters using quantitative PCR. Mol Biochem Parasitol 2015; 200:19-24. [PMID: 25936954 DOI: 10.1016/j.molbiopara.2015.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 04/10/2015] [Accepted: 04/11/2015] [Indexed: 11/20/2022]
Abstract
Mikrocytos mackini is an internationally regulated pathogen and causative agent of Denman Island disease in Pacific oysters Crassostrea gigas. Recent phylogenetic breakthroughs have placed this parasite within a highly divergent and globally distributed eukaryotic lineage that has been designated a new taxonomic order, Mikrocytida. The discovery of this new radiation of parasites is accompanied by a heightened awareness of the many knowledge gaps that exist with respect to the general biology, epizootiology, and potential impact of mikrocytid parasites on hosts, ecosystems, and commercial fisheries. It has also highlighted current shortcomings regarding our ability to detect these organisms. In this study, we developed a species-specific, sensitive, and quantitative method for detecting M. mackini DNA from host tissues using probe-based real-time qPCR technology. A limit of sensitivity between 2 and 5 genome copy equivalents was achieved in a reaction matrix containing ≥ 40 ng/μL host gDNA without inhibition. This detection proved superior to existing methods based on conventional PCR, histology or gross pathology and is the first species-specific diagnostic test for M. mackini. Quantitative assessment of parasite DNA using this assay remained accurate to between 10 and 50 copies identifying that during infection, M. mackini DNA was significantly more prevalent in hemolymph, labial palp, and mid-body cross-sections compared to mantle or adductor muscle. DNA extracted from a mid-body cross-section also provided the highest likelihood for detection during diagnostic screening of infected oysters. Taken together, these findings provide strong analytical evidence for the adoption of qPCR as the new reference standard for detecting M. mackini and give preliminary insight into the distribution of the parasite within host tissues. Standardised operating methodologies for sample collection and qPCR testing are provided to aid in the international regulatory diagnosis of M. mackini and serve as a useful platform for the future development of multiplexed or alternate mikrocytid species detection.
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Abbott CL, Meyer GR, Lowe G, Kim E, Johnson SC. Molecular taxonomy of Mikrocytos boweri sp. nov. from Olympia oysters Ostrea lurida in British Columbia, Canada. DISEASES OF AQUATIC ORGANISMS 2014; 110:65-70. [PMID: 25060498 DOI: 10.3354/dao02699] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Mikrocytos mackini is a microcell parasite that usually infects Crassostrea gigas distributed along the Pacific Northwest coast of North America. For many years, M. mackini was the only known species in the genus, but there have been multiple recent findings of genetically divergent forms of Mikrocytos in different hosts and in distantly located geographic locations. This note describes M. boweri sp. nov. found in Olympia oysters Ostrea lurida collected from and native to British Columbia, Canada, primarily using a molecular taxonomic approach.
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Affiliation(s)
- Cathryn L Abbott
- Department of Fisheries and Oceans, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, BC V9T 6N7, Canada
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45
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Carnegie RB, Engelsma MY. Microcell parasites of molluscs: introduction to DAO Special 7. DISEASES OF AQUATIC ORGANISMS 2014; 110:1-4. [PMID: 25060493 DOI: 10.3354/dao02787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
First discovered decades ago, microcell protistan parasites of the genera Bonamia and Mikrocytos remain relevant today for their economic impacts on growing molluscan aquaculture industries and fisheries. Bonamia parasites have received more attention over the years in part because they are more widespread and thus of wider concern, but there has been renewed interest in Mikrocytos recently with the generation of important new findings. Among these has been the surprising observation that Mikrocytos has phylogenetic affinities to the Rhizaria, which includes the haplosporidian protists and the genus Bonamia. This Diseases of Aquatic Organisms Special, emerging from the 5th Meeting of the Microcell Working Group held at the Central Veterinary Institute, Lelystad, the Netherlands, in February 2012, presents new insights into Mikrocytos and Bonamia diversity, distributions, diagnostics, ultrastructure, and infection dynamics, and captures major developments in the field since the last review of these genera in 2004.
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Affiliation(s)
- Ryan B Carnegie
- Virginia Institute of Marine Science, College of William & Mary, PO Box 1346, Gloucester Point, Virginia 23062, USA
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Abbott CL, Meyer GR. Review of Mikrocytos microcell parasites at the dawn of a new age of scientific discovery. DISEASES OF AQUATIC ORGANISMS 2014; 110:25-32. [PMID: 25060495 DOI: 10.3354/dao02788] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The genus Mikrocytos is traditionally known for Mikrocytos mackini, the microcell parasite that typically infects Pacific oysters along the west coast of North America. Multiple factors have conspired to create difficulty for scientific research on Mikrocytos parasites. These include their tiny cell size, infections that are often of light intensity, lack of suitable cell lines and techniques for in vitro culture, and the seasonal nature of infections. The extreme rate of molecular evolution in Mikrocytos stymied new species discovery and confounded attempts to resolve its phylogenetic position for many years. Fortunately, 2 recent landmark studies have paved the way forward for future research by drastically changing our understanding of the evolution and diversity of these parasites. No longer an orphan eukaryotic lineage, the phylogenetic placement of Mikrocytos has been confidently resolved within Rhizaria and as sister taxon to Haplosporidia. The genus has also found a taxonomic home within the newly-discovered order, Mikrocytida - a globally distributed lineage of parasites infecting a wide range of invertebrate hosts. Here we review available scientific information on Mikrocytos parasites including their evolution and diversity, host and geographic ranges, epizootiology, and detection of the regulated pathogen, M. mackini. We also make recommendations towards a consistent taxonomic framework for this genus by minimally suggesting the use of 18S rDNA sequence, host species information, and histopathological presentation in new species descriptions. This is timely given that we are likely embarking on a new era of scientific advancements, including species discovery, in this genus and its relatives.
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Affiliation(s)
- Cathryn L Abbott
- Department of Fisheries and Oceans, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, BC V9T 6N7, Canada
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47
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Policy, phylogeny, and the parasite. Trends Parasitol 2014; 30:274-81. [DOI: 10.1016/j.pt.2014.04.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 03/31/2014] [Accepted: 04/02/2014] [Indexed: 11/20/2022]
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48
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Abstract
DNA-based methods continue to unveil the diversity and evolutionary origins of life on Earth. 'Next generation' methods have just solved a long-standing puzzle by uncovering previously unseen yet globally distributed diversity within a lineage of amitochondriate parasites affecting commercially exploited aquatic hosts. This discovery will impact both pure and applied research fields.
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Affiliation(s)
- Cathryn L Abbott
- Department of Fisheries and Oceans, Pacific Biological Station, Nanaimo, BC V9R 5K6, Canada.
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