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Erkinharju T, Hansen H, Garseth ÅH. First detection of Ichthyophonus sp. in invasive wild pink salmon (Oncorhynchus gorbuscha) from the North Atlantic Ocean. JOURNAL OF FISH DISEASES 2024:e13990. [PMID: 38924607 DOI: 10.1111/jfd.13990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 06/10/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024]
Abstract
Pacific pink salmon (Oncorhynchus gorbuscha) were deliberately introduced to rivers surrounding the White Sea and has spread to Norway and several other countries surrounding the North Atlantic Ocean. In August 2021, a female pink salmon displaying pale gills and abnormal behaviour was captured in River Lakselva in Northern Norway and later submitted to the Norwegian Veterinary Institute (NVI) for post-mortem examination. Histological examination of organ samples revealed structures indicative of systemic ichthyophoniasis, caused by Ichthyophonus sp. The parasites appeared to be especially abundant in the heart and skeletal musculature, and local tissue responses were assessed to be absent or very mild. Sequences of the ribosomal 18S rRNA and the mitochondrial cytochrome oxidase 1 (CO1) genes confirmed the diagnosis and identified the pathogen as Ichthyophonus sp. The CO1 sequence further established that the isolate from pink salmon was most similar to sequences of Ichthyophonus sp. from Atlantic salmon, Salmo salar, from the Atlantic Ocean on the east coast of the US and from Atlantic herring, Clupea harengus, from Iceland. We here report the first detection of Ichthyophonus sp. in pink salmon in the North Atlantic Ocean.
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Storesund JE, Nylund CDS, Karlsbakk E, Giulietti L, Bao M, Cipriani P, Levsen A. High prevalence of Ichthyophonus sp. infections in Northeast Atlantic mackerel (Scomber scombrus). JOURNAL OF FISH DISEASES 2022; 45:1243-1249. [PMID: 35604646 PMCID: PMC9543888 DOI: 10.1111/jfd.13652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/30/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Julia E. Storesund
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
| | - Caroline da Silva Nylund
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
- Department of Biological SciencesUniversity of Bergen (UiB)BergenNorway
| | - Egil Karlsbakk
- Department of Biological SciencesUniversity of Bergen (UiB)BergenNorway
- Pathogens and Disease TransferInstitute of Marine Research (IMR)BergenNorway
| | - Lucilla Giulietti
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
| | - Miguel Bao
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
| | - Paolo Cipriani
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
- Department of Public Health and Infectious DiseasesSection of Parasitology, Sapienza University of RomeRomeItaly
| | - Arne Levsen
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
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Gregg JL, Hershberger PK, Neat AS, Jayasekera HT, Ferguson JA, Powers RL, Purcell MK. A phylogeny based on cytochrome-c oxidase gene sequences identifies sympatric Ichthyophonus genotypes in the NE Pacific Ocean. DISEASES OF AQUATIC ORGANISMS 2022; 150:61-67. [PMID: 35833545 DOI: 10.3354/dao03677] [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
In recent decades, evidence has accumulated to suggest that the widespread and highly variable parasite Ichthyophonus hoferi is actually a species complex. Highly plastic morphology and a general lack of defining structures has contributed to the likely underestimate of biodiversity within this group. Molecular methods are a logical next step in the description of these parasites, but markers used to date have been too conserved to resolve species boundaries. Here we use mitochondrial encoded cytochrome-c oxidase (MTCO1) gene sequences and phylogenic analysis to compare Ichthyophonus spp. isolates from several marine and anadromous fish hosts. The resulting phylogeny displays lineage separation among isolates and possible host/niche segregation not previously described. The parasite type that infects Pacific herring Clupea pallasii, Atlantic herring C. harengus, Atlantic salmon Salmo salar, and Pacific staghorn sculpin Oligocottus maculosus (Clade A) is different from that which infects Chinook salmon Oncorhynchus tshawytscha, walleye pollock Gadus chalcogrammus, Greenland halibut Reinhardtius hippoglossoides, and Pacific halibut Hippoglossus stenolepsis (Clade B). MTCO1 sequences confirmed the presence of a more divergent Ichthyophonus sp. isolated from American shad Alosa sapidissima in rivers of eastern North America (Clade C), while American shad introduced to the Pacific Ocean are infected with the same parasite that infects Pacific herring (Clade A). Currently there are no consensus criteria for delimiting species within Ichthyophonidae, but MTCO1 sequences hold promise as a potential species identifying marker and useful epizootiological tool.
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Affiliation(s)
- Jacob L Gregg
- U.S. Geological Survey - Western Fisheries Research Center, Marrowstone Marine Field Station, 616 Marrowstone Point Road, Nordland, WA 98358, USA
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Gregg JL, Powers RL, Purcell MK, Friedman CS, Hershberger PK. Ichthyophonus parasite phylogeny based on ITS rDNA structure prediction and alignment identifies six clades, with a single dominant marine type. DISEASES OF AQUATIC ORGANISMS 2016; 120:125-141. [PMID: 27409236 DOI: 10.3354/dao03017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Despite their widespread, global impact in both wild and cultured fishes, little is known of the diversity, transmission patterns, and phylogeography of parasites generally identified as Ichthyophonus. This study constructed a phylogeny based on the structural alignment of internal transcribed spacer (ITS) rDNA sequences to compare Ichthyophonus isolates from fish hosts in the Atlantic and Pacific oceans, and several rivers and aquaculture sites in North America, Europe, and Japan. Structure of the Ichthyophonus ITS1-5.8S-ITS2 transcript exhibited several homologies with other eukaryotes, and 6 distinct clades were identified within Ichthyophonus. A single clade contained a majority (71 of 98) of parasite isolations. This ubiquitous Ichthyophonus type occurred in 13 marine and anadromous hosts and was associated with epizootics in Atlantic herring, Chinook salmon, and American shad. A second clade contained all isolates from aquaculture, despite great geographic separation of the freshwater hosts. Each of the 4 remaining clades contained isolates from single host species. This study is the first to evaluate the genetic relationships among Ichthyophonus species across a significant portion of their host and geographic range. Additionally, parasite infection prevalence is reported in 16 fish species.
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Affiliation(s)
- Jacob L Gregg
- Marrowstone Marine Field Station, US Geological Survey, 616 Marrowstone Point Road, Nordland, Washington 98358, USA
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Hershberger PK, Gregg JL, Hart LM, Moffitt S, Brenner R, Stick K, Coonradt E, Otis EO, Vollenweider JJ, Garver KA, Lovy J, Meyers TR. The parasite Ichthyophonus sp. in Pacific herring from the coastal NE Pacific. JOURNAL OF FISH DISEASES 2016; 39:395-410. [PMID: 25828232 DOI: 10.1111/jfd.12370] [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] [Received: 10/20/2014] [Revised: 01/21/2015] [Accepted: 02/14/2015] [Indexed: 05/27/2023]
Abstract
The protistan parasite Ichthyophonus occurred in populations of Pacific herring Clupea pallasii Valenciennes throughout coastal areas of the NE Pacific, ranging from Puget Sound, WA north to the Gulf of Alaska, AK. Infection prevalence in local Pacific herring stocks varied seasonally and annually, and a general pattern of increasing prevalence with host size and/or age persisted throughout the NE Pacific. An exception to this zoographic pattern occurred among a group of juvenile, age 1+ year Pacific herring from Cordova Harbor, AK in June 2010, which demonstrated an unusually high infection prevalence of 35%. Reasons for this anomaly were hypothesized to involve anthropogenic influences that resulted in locally elevated infection pressures. Interannual declines in infection prevalence from some populations (e.g. Lower Cook Inlet, AK; from 20-32% in 2007 to 0-3% during 2009-13) or from the largest size cohorts of other populations (e.g. Sitka Sound, AK; from 62.5% in 2007 to 19.6% in 2013) were likely a reflection of selective mortality among the infected cohorts. All available information for Ichthyophonus in the NE Pacific, including broad geographic range, low host specificity and presence in archived Pacific herring tissue samples dating to the 1980s, indicate a long-standing host-pathogen relationship.
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Affiliation(s)
- P K Hershberger
- U. S. Geological Survey, Western Fisheries Research Center - Marrowstone Marine Field Station, Nordland, WA, USA
| | - J L Gregg
- U. S. Geological Survey, Western Fisheries Research Center - Marrowstone Marine Field Station, Nordland, WA, USA
| | - L M Hart
- U. S. Geological Survey, Western Fisheries Research Center - Marrowstone Marine Field Station, Nordland, WA, USA
| | - S Moffitt
- Alaska Department of Fish and Game (ADF&G) - Commercial Fisheries, Cordova, AK, USA
| | - R Brenner
- Alaska Department of Fish and Game (ADF&G) - Commercial Fisheries, Cordova, AK, USA
| | - K Stick
- Washington Department of Fish and Wildlife, Fish Program, Region 4 LaConner District Office, La Conner, WA, USA
| | - E Coonradt
- ADF&G - Commercial Fisheries, Sitka, AK, USA
| | - E O Otis
- ADF&G - Commercial Fisheries, Homer, AK, USA
| | - J J Vollenweider
- National Oceanic and Atmospheric Administration, Alaska Fisheries Science Center - Auke Bay Laboratories, Juneau, AK, USA
| | - K A Garver
- Fisheries and Oceans Canada - Pacific Biological Station, Nanaimo, BC, Canada
| | - J Lovy
- New Jersey Division of Fish & Wildlife, Office of Fish & Wildlife Health & Forensics, Oxford, NJ, USA
| | - T R Meyers
- ADF&G - Juneau Fish Pathology Laboratory, Juneau, AK, USA
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Conway CM, Purcell MK, Elliott DG, Hershberger PK. Detection of Ichthyophonus by chromogenic in situ hybridization. JOURNAL OF FISH DISEASES 2015; 38:853-857. [PMID: 25271555 DOI: 10.1111/jfd.12300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 07/10/2014] [Accepted: 07/21/2014] [Indexed: 06/03/2023]
Affiliation(s)
- C M Conway
- US Geological Survey-Western Fisheries Research Center, Seattle, WA, USA
| | - M K Purcell
- US Geological Survey-Western Fisheries Research Center, Seattle, WA, USA
| | - D G Elliott
- US Geological Survey-Western Fisheries Research Center, Seattle, WA, USA
| | - P K Hershberger
- US Geological Survey-Marrowstone Marine Field Station, Nordland, WA, USA
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Gozlan RE, Marshall WL, Lilje O, Jessop CN, Gleason FH, Andreou D. Current ecological understanding of fungal-like pathogens of fish: what lies beneath? Front Microbiol 2014. [PMID: 24600442 DOI: 10.3389/fmicb.2014.00062/bibtex] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
Despite increasingly sophisticated microbiological techniques, and long after the first discovery of microbes, basic knowledge is still lacking to fully appreciate the ecological importance of microbial parasites in fish. This is likely due to the nature of their habitats as many species of fish suffer from living beneath turbid water away from easy recording. However, fishes represent key ecosystem services for millions of people around the world and the absence of a functional ecological understanding of viruses, prokaryotes, and small eukaryotes in the maintenance of fish populations and of their diversity represents an inherent barrier to aquatic conservation and food security. Among recent emerging infectious diseases responsible for severe population declines in plant and animal taxa, fungal and fungal-like microbes have emerged as significant contributors. Here, we review the current knowledge gaps of fungal and fungal-like parasites and pathogens in fish and put them into an ecological perspective with direct implications for the monitoring of fungal fish pathogens in the wild, their phylogeography as well as their associated ecological impact on fish populations. With increasing fish movement around the world for farming, releases into the wild for sport fishing and human-driven habitat changes, it is expected, along with improved environmental monitoring of fungal and fungal-like infections, that the full extent of the impact of these pathogens on wild fish populations will soon emerge as a major threat to freshwater biodiversity.
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Affiliation(s)
- Rodolphe E Gozlan
- Unité Mixte de Recherche Biologie des Organismes et Écosystèmes Aquatiques (IRD 207, CNRS 7208, MNHN, UPMC), Muséum National d'Histoire Naturelle Paris Cedex, France ; Centre for Conservation Ecology and Environmental Sciences, School of Applied Sciences, Bournemouth University Poole, Dorset, UK
| | - Wyth L Marshall
- BC Centre for Aquatic Health Sciences Campbell River, BC, Canada
| | - Osu Lilje
- School of Biological Sciences, University of Sydney Sydney, NSW, Australia
| | - Casey N Jessop
- School of Biological Sciences, University of Sydney Sydney, NSW, Australia
| | - Frank H Gleason
- School of Biological Sciences, University of Sydney Sydney, NSW, Australia
| | - Demetra Andreou
- Centre for Conservation Ecology and Environmental Sciences, School of Applied Sciences, Bournemouth University Poole, Dorset, UK
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Gozlan RE, Marshall WL, Lilje O, Jessop CN, Gleason FH, Andreou D. Current ecological understanding of fungal-like pathogens of fish: what lies beneath? Front Microbiol 2014; 5:62. [PMID: 24600442 PMCID: PMC3928546 DOI: 10.3389/fmicb.2014.00062] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 01/30/2014] [Indexed: 11/13/2022] Open
Abstract
Despite increasingly sophisticated microbiological techniques, and long after the first discovery of microbes, basic knowledge is still lacking to fully appreciate the ecological importance of microbial parasites in fish. This is likely due to the nature of their habitats as many species of fish suffer from living beneath turbid water away from easy recording. However, fishes represent key ecosystem services for millions of people around the world and the absence of a functional ecological understanding of viruses, prokaryotes, and small eukaryotes in the maintenance of fish populations and of their diversity represents an inherent barrier to aquatic conservation and food security. Among recent emerging infectious diseases responsible for severe population declines in plant and animal taxa, fungal and fungal-like microbes have emerged as significant contributors. Here, we review the current knowledge gaps of fungal and fungal-like parasites and pathogens in fish and put them into an ecological perspective with direct implications for the monitoring of fungal fish pathogens in the wild, their phylogeography as well as their associated ecological impact on fish populations. With increasing fish movement around the world for farming, releases into the wild for sport fishing and human-driven habitat changes, it is expected, along with improved environmental monitoring of fungal and fungal-like infections, that the full extent of the impact of these pathogens on wild fish populations will soon emerge as a major threat to freshwater biodiversity.
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Affiliation(s)
- Rodolphe E. Gozlan
- Unité Mixte de Recherche Biologie des Organismes et Écosystèmes Aquatiques (IRD 207, CNRS 7208, MNHN, UPMC), Muséum National d'Histoire NaturelleParis Cedex, France
- Centre for Conservation Ecology and Environmental Sciences, School of Applied Sciences, Bournemouth UniversityPoole, Dorset, UK
| | | | - Osu Lilje
- School of Biological Sciences, University of SydneySydney, NSW, Australia
| | - Casey N. Jessop
- School of Biological Sciences, University of SydneySydney, NSW, Australia
| | - Frank H. Gleason
- School of Biological Sciences, University of SydneySydney, NSW, Australia
| | - Demetra Andreou
- Centre for Conservation Ecology and Environmental Sciences, School of Applied Sciences, Bournemouth UniversityPoole, Dorset, UK
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White VC, Morado JF, Crosson LM, Vadopalas B, Friedman CS. Development and validation of a quantitative PCR assay for Ichthyophonus spp. DISEASES OF AQUATIC ORGANISMS 2013; 104:69-81. [PMID: 23670081 DOI: 10.3354/dao02579] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Members of the genus Ichthyophonus are trophically transmitted, cosmopolitan parasites that affect numerous fish species worldwide. A quantitative PCR (qPCR) assay specific for genus Ichthyophonus 18S ribosomal DNA was developed for parasite detection and surveillance. The new assay was tested for precision, repeatability, reproducibility, and both analytical sensitivity and specificity. Diagnostic sensitivity and specificity were estimated using tissue samples from a wild population of walleye pollock Theragra chalcogramma. Ichthyophonus sp. presence in tissue samples was determined by qPCR, conventional PCR (cPCR), and histology. Parasite prevalence estimates varied depending upon the detection method employed and tissue type tested. qPCR identified the greatest number of Ichthyophonus sp.-positive cases when applied to walleye pollock skeletal muscle. The qPCR assay proved sensitive and specific for Ichthyophonus spp. DNA, but like cPCR, is only a proxy for infection. When compared to cPCR, qPCR possesses added benefits of parasite DNA quantification and a 100-fold increase in analytical sensitivity. Because this novel assay is specific for known members of the genus, it is likely appropriate for detecting Ichthyophonus spp. DNA in various hosts from multiple regions. However, species-level identification and isotype variability would require DNA sequencing. In addition to distribution and prevalence applications, this assay could be modified and adapted for use with zooplankton or environmental samples. Such applications could aid in investigating alternate routes of transmission and life history strategies typical to members of the genus Ichthyophonus.
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Affiliation(s)
- Vanessa C White
- National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center, Resource Assessment and Conservation Engineering Division, Seattle, Washington 98115, USA
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Zilberg D, Jones JB, Burger MAA, Nicholls PK, Nolan D, Crockford M, Stephens F. New pathological condition in cultured mulloway Argyrosomus japonicus: histopathological, ultrastructural and molecular studies. DISEASES OF AQUATIC ORGANISMS 2012; 100:219-230. [PMID: 22968790 DOI: 10.3354/dao02495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Mulloway Argyrosomus japonicus is a native fish species in Western Australia, for which aquaculture production has recently been developed. A single cohort was stocked in a cage offshore at Geraldton, Western Australia, at a water depth of 6 m. Fish appeared healthy before stocking. Routine histological analysis was carried out from 10 mo post stocking and until completion of harvest (about 2.5 yr post stocking). No gross pathology was evident. Microscopically, however, granulomatous lesions were present in the kidneys of almost 100% of the fish examined. Enclosed in the granuloma was an aggregate of organisms, 4.2 to 5.4 µm in diameter. Kidney granulomas appeared as multi-focal aggregates. Granulomas at different stages of formation and finally fibrosing granulomas were observed. Granulomas also appeared infrequently in other organs: a few granulomas were found in the liver and spleen and a single granuloma in the heart of one fish. Transmission electron microscopy (TEM) revealed that the organism was composed of 2 cells, an outer cell enclosing an inner cell. The inner cell was surrounded by a double membrane and the outer cell by a single membrane. Cellular material, presumably of parasitic nature, surrounded the outer cell. The organism contained primitive mitochondria and abundant free ribosomes. Small subunit ribosomal DNA (SSU rDNA) sequence obtained by PCR revealed an 84% sequence identity with the myxosporean Latyspora scomberomori. Based on TEM and preliminary molecular results, we suggest that the organism is the extrasporogonic developmental stage of a myxozoan parasite, which failed to form spores in the mulloway host.
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Affiliation(s)
- Dina Zilberg
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben Gurion 84990, Israel
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Hershberger PK, Pacheco CA, Gregg JL, Purcell MK, LaPatra SE. Differential Survival of Ichthyophonus Isolates Indicates Parasite Adaptation to its Host Environment. J Parasitol 2008; 94:1055-9. [DOI: 10.1645/ge-1553.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 02/18/2008] [Indexed: 11/10/2022] Open
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Marshall WL, Celio G, McLaughlin DJ, Berbee ML. Multiple isolations of a culturable, motile Ichthyosporean (Mesomycetozoa, Opisthokonta), Creolimax fragrantissima n. gen., n. sp., from marine invertebrate digestive tracts. Protist 2008; 159:415-33. [PMID: 18539526 DOI: 10.1016/j.protis.2008.03.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Accepted: 03/22/2008] [Indexed: 10/22/2022]
Abstract
A fragrant, spherical, osmotrophic eukaryote was isolated 27 times from the digestive tracts of marine invertebrates collected from the Northeast Pacific. The isolates were cultured from 7 animal collections over a 2-year period, most from the peanut worm, Phascolosoma agassizii. A small subunit ribosomal DNA phylogeny placed the spherical organism within the ichthyosporea, closest to Sphaeroforma arctica and Pseudoperkinsus tapetis. Supporting the close relationship of isolates, the sequences of ribosomal gene internal transcribed spacers determined for 26 isolates were identical, as were the elongation factor 1-alpha-like gene fragments from 7 isolates. Dispersal via amoeboid cells distinguished this species from its closest relatives and led to the erection of a new genus and species, "Creolimax fragrantissima." Vegetative cells reproduced asexually in vitro after they reached 30-60 microm in diameter by producing amoebae or endospores, which escaped through openings in the parent cell wall. Ultrathin sections of vegetative cells prepared by high-pressure-freeze substitution provided some of the first images of ichthyosporean spindle pole bodies and document, for the first time, tubular extensions of the plasma membrane into an electron-translucent inner layer of the cell wall. Ichthyosporeans are parasites and commensals of animals and culturable species are few. Because "C. fragrantissima" can be isolated regularly and repeatedly from nature and then grown easily through cycles of asexual reproduction, it has the potential to serve as a model organism for further research into marine ichthyosporeans.
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Affiliation(s)
- Wyth L Marshall
- Department of Botany, University of British Columbia, Vancouver, B.C., Canada V6T 1Z4.
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Mendoza L, Taylor JW, Ajello L. The class mesomycetozoea: a heterogeneous group of microorganisms at the animal-fungal boundary. Annu Rev Microbiol 2003; 56:315-44. [PMID: 12142489 DOI: 10.1146/annurev.micro.56.012302.160950] [Citation(s) in RCA: 232] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
When the enigmatic fish pathogen, the rosette agent, was first found to be closely related to the choanoflagellates, no one anticipated finding a new group of organisms. Subsequently, a new group of microorganisms at the boundary between animals and fungi was reported. Several microbes with similar phylogenetic backgrounds were soon added to the group. Interestingly, these microbes had been considered to be fungi or protists. This novel phylogenetic group has been referred to as the DRIP clade (an acronym of the original members: Dermocystidium, rosette agent, Ichthyophonus, and Psorospermium), as the class Ichthyosporea, and more recently as the class Mesomycetozoea. Two orders have been described in the mesomycetozoeans: the Dermocystida and the Ichthyophonida. So far, all members in the order Dermocystida have been pathogens either of fish (Dermocystidium spp. and the rosette agent) or of mammals and birds (Rhinosporidium seeberi), and most produce uniflagellated zoospores. Fish pathogens also are found in the order Ichthyophonida, but so are saprotrophic microbes. The Ichthyophonida species do not produce flagellated cells, but many produce amoeba-like cells. This review provides descriptions of the genera that comprise the class Mesomycetozoea and highlights their morphological features, pathogenic roles, and phylogenetic relationships.
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Affiliation(s)
- Leonel Mendoza
- Medical Technology Program, Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing 48824-1030, USA.
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Jøstensen JP, Sperstad S, Johansen S, Landfald B. Molecular-phylogenetic, structural and biochemical features of a cold-adapted, marine ichthyosporean near the animal-fungal divergence, described from in vitro cultures. Eur J Protistol 2002. [DOI: 10.1078/0932-4739-00855] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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