Nutritional studies of a flagellated protozoan <i>Hexamita inflata</i> from the Canadian oyster, <i>Crassostrea virginica</i>

Khouw, B T; McCurdy, Howard D.

doi:10.1139/m68-139

Cited by 5 publications

(3 citation statements)

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“…are of particular importance to aquaculture, as they can cause devastating outbreaks of systemic infections in both ornamental and food fish [6,[20][21][22][23][24][25][26][27]. These ubiquitous flagellates occur in cold, temperate and tropical waters, and infect a wide range of freshwater [21,23,24] and marine fish [27][28][29][30][31], as well as shellfish and crustaceans [23,24,[32][33][34]. Fish farmed in aquaculture, an industry of growing importance as wild fish stocks become increasingly depleted, are particularly susceptible to disease outbreaks caused by diplomonads.…”

Section: Introductionmentioning

confidence: 99%

Spironucleus species: Economically-Important Fish Pathogens and Enigmatic Single-Celled Eukaryotes

Williams

Lloyd

Poynton³

et al. 2013

J Aquac Res Development

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Diplomonads are aerotolerant anaerobic, binucleate flagellates, which are commonly found in the intestinal tract of wild and farmed fish. Of the diplomonad genera, Spironucleus, composed of opportunistic pathogens, poses the greatest threat to aquaculture. Immunocompromised hosts or fish without acquired immunity are thought to be more susceptible to parasitism by these otherwise commensal agents. Accumulation of flagellates along the intestinal tract often leads to systemic Spironucleosis causing high mortality of both ornamental and food fish in aquaculture. The life cycle of these piscine diplomonads is direct, consisting of a motile, parasitic trophozoite and a resilient encysted stage, which facilitates water-borne transmission. Confusion in the nomenclature, as well as numerous reassignments of taxa, hampers our understanding of host range and geographical distribution of fish diplomonads. Accurate identification requires transmission electron microscopy to characterise intricate ultrastructural features. Additionally, sequencing of the small subunit ribosomal RNA gene allows identification of cryptic Spironucleus spp.In vitro culture provides a convenient source of flagellates for biochemical and physiological research, allowing the identification of novel parasite-specific molecular pathways such as H 2 production within Spironucleus sp. This provides insight into the pathogenicity of these organisms and offers potential new targets for chemotherapy. Restrictions on the administration of the current drug of choice, metronidazole, in aquacultural settings, as well as reported cases of drug resistance, means that control of Spironucleosis is especially difficult. Allium sativum (garlic)-derived compounds have proven highly effective at inhibiting parasite growth in vitro, showing great potential as a novel alternative therapy in the treatment of Spironucleosis. Further characterisation of the biochemistry, pathogenicity and taxonomy of fish diplomonads is required in order to fully appreciate the true impact and economic consequences of Spironucleus spp. in aquaculture.

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Section: Introductionmentioning

confidence: 99%

Spironucleus species: Economically-Important Fish Pathogens and Enigmatic Single-Celled Eukaryotes

Williams

Lloyd

Poynton³

et al. 2013

J Aquac Res Development

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“…A lipid requirement has been documented only for the heterotrophic species O. marina , which required a quinone (Droop and Doyle 1966; Droop and Pennock 1971). Biochemical requirements for fatty acids and/or sterols have been identified, however, for several non‐dinoflagellate protists (Allen et al 1966; Biagini et al 1998; Hanna and Lilly 1974; Holz, Erwin, and Wagner 1961a; Holz et al 1961b, 1962; Khouw and McCurdy 1968; Miller and Johnson 1960; Soldo and van Wagtendonk 1967). Lipids may be required for or stimulatory to the growth of most phagotrophic protists.…”

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confidence: 99%

“…The dominant fatty acid in soy lecithin is the unsaturated fatty acid, linoleic acid (18:2n‐6; 60%, w/v, of total fatty acids), but significant concentrations of palmitic (16:0; 18%, w/v), oleic (18:1n‐9; 11%, w/v), and linolenic (18:3n‐3; 9%, w/v) acid are also present (Schneider 1989). Complex lipids in culture media used for the axenic culture of heterotrophic protists often have been replaced successfully with oleic or linoleic acid (Hanna and Lilly 1974; Khouw and McCurdy 1968; Miller and Johnson 1960; Soldo, Godoy, and van Wagetendonk 1966). The fatty acid profiles of lecithin and chicken egg yolk suggest that these two fatty acids should be investigated further for the ability to support or stimulate P. shumwaye growth.…”

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confidence: 99%

Axenic Culture of the Heterotrophic Dinoflagellate Pfiesteria shumwayae in a Semi‐Defined Medium

Skelton

Burkholder

Parrow

2009

J Eukaryotic Microbiology

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ABSTRACT. A semi-defined, biphasic culture medium was developed that supported the axenic growth of three strains of the heterotrophic dinoflagellate Pfiesteria shumwayae. Maximum cell yields and division rates in the semi-defined medium ranged from 0.1 Â 10 5 to 4.0 Â 10 5 cells/ml and 0.5 to 1.7 divisions/day, respectively, and depended on the concentration of the major components in the medium as well as the P. shumwayae strain. The medium contained high concentrations of certain dissolved and particulate organic compounds, including amino acids and lipids. Pfiesteria shumwayae flagellated cells were attracted to insoluble lipids present in the medium and appeared to feed on the lipid particles, suggesting that phagocytosis may be required for growth in axenic culture. Development of a semi-defined medium represents significant progress toward a completely defined axenic culture medium and subsequent determination of the biochemical requirements of P. shumwayae, needed to advance understanding of the nutritional ecology of this species. Further, this medium provides an economical, simplified method for generating high cell densities of P. shumwayae in axenic culture that will facilitate controlled investigations on the physiology and biochemistry of this heterotrophic dinoflagellate.

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Flagellate Parasites of Fish

Becker¹

1977

Taxonomy, Kinetoplastids, and Flagellates of Fish

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Nutritional studies of a flagellated protozoan Hexamita inflata from the Canadian oyster, Crassostrea virginica

Cited by 5 publications

References 0 publications

Spironucleus species: Economically-Important Fish Pathogens and Enigmatic Single-Celled Eukaryotes

Spironucleus species: Economically-Important Fish Pathogens and Enigmatic Single-Celled Eukaryotes

Axenic Culture of the Heterotrophic Dinoflagellate Pfiesteria shumwayae in a Semi‐Defined Medium

Flagellate Parasites of Fish

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