Host-Specific and pH-Dependent Microbiomes of Copepods in an Extensive Rearing System.

Copepods are to an increasing extent cultivated as feed for mariculture fish larvae with variable production success. In the temperate climate zone, this production faces seasonal limitation due to changing abiotic factors, in particular temperature and light. Furthermore, the production of copepods may be influenced by biotic factors of the culture systems, such as competing microorganisms, harmful algae, or other eukaryotes and prokaryotes that may be non-beneficial for the copepods.

The molecular phylogeny of the type-species of Oodinium Chatton, 1912 (Dinoflagellata: Oodiniaceae), a highly divergent parasitic dinoflagellate with non-dinokaryotic characters.

Oodinium pouchetii (Lemmermann, 1899) Chatton, 1912, the first described parasitic dinoflagellate, is the type of the Oodiniaceae Chatton, 1920. In the taxonomical schemes, this family of metazoan parasites includes Amyloodinium Brown & Hovasse, 1946 and Piscinoodinium Lom, 1981 that are responsible of important damages in fish aquaculture. Species of Oodinium Chatton, 1912 have unique characteristics such as the possession of both non-dinokaryotic and dinokaryotic nuclei within the life-cycle, and the absence of the transversal (cingulum) and longitudinal (sulcus) surface grooves in the parasitic stage.

Molecular Phylogeny of the Parasitic Dinoflagellate Chytriodinium within the Gymnodinium Clade (Gymnodiniales, Dinophyceae).

The dinoflagellate genus Chytriodinium, an ectoparasite of copepod eggs, is reported for the first time in the North and South Atlantic Oceans. We provide the first large subunit rDNA (LSU rDNA) and Internal Transcribed Spacer 1 (ITS1) sequences, which were identical in both hemispheres for the Atlantic Chytriodinium sp. The first complete small subunit ribosomal DNA (SSU rDNA) of the Atlantic Chytriodinium sp.

Annual and spatial variability in endo- and ectoparasite infections of North Sea cod (Gadus morhua Linnaeus, 1758) larvae, post-larvae and juveniles.

A parasitological investigation was performed on a total of 5380 Atlantic cod larvae, post-larvae and small juveniles sampled from the North Sea during a period of five years. The copepod Caligus elongatus (Von Nordmann, 1832) and the nematode Hysterothylacium aduncum (Rudolphi, 1802) were found at a relatively high prevalence of infection (4.6% and 5.

Parvilucifera rostrata sp. nov. (Perkinsozoa), a novel parasitoid that infects planktonic dinoflagellates.

The diversity and ecological roles of protists in marine plankton are still poorly known. In 2011, we made a substantial effort to isolate parasites into cultures during the course of blooms of the toxic microalga Alexandrium minutum (Dinophyceae) in two estuaries (the Penzé and the Rance, Brittany coast, north-west of France). In total, 99 parasitic strains were obtained.

Effects of excretory/secretory products from Anisakis simplex (Nematoda) on immune gene expression in rainbow trout (Oncorhynchus mykiss).

Excretory/secretory (ES) products are molecules produced by parasitic nematodes, including larval Anisakis simplex, a parasite occurring in numerous marine fish hosts. The effects of these substances on host physiology have not been fully described. The present work elucidates the influence of ES substances on the fish immune system by measuring immune gene expression in spleen and liver of rainbow trout (Oncorhynchus mykiss) injected intraperitoneally with ES products isolated from A.

Occurrence of Diplostomum pseudospathaceum Niewiadomska, 1984 and D. mergi Dubois, 1932 (Digenea: Diplostomidae) in Danish freshwater snails: ecological and molecular data.

Freshwater pulmonate snails from three locations in Lake Furesø north of Copenhagen were screened for infection with furcocercariae (by shedding in the laboratory) and recovered parasite larvae were diagnosed by molecular methods (by performing PCR of rDNA and sequencing the internal transcribed spacer [ITS] region). Overall prevalence of infection in snails was 2%. Recovered cercariae from Lymnaea stagnalis (Linnaeus) were diagnosed as Diplostomum pseudospathaceum Niewiadomska, 1984 (prevalence 4%) and cercariae from Radix balthica (Linnaeus) as D.

Tetracapsuloides bryosalmonae and PKD in juvenile wild salmonids in Denmark.

The myxozoan Tetracapsuloides bryosalmonae is the causative agent of proliferative kidney disease (PKD), a widespread and serious condition in salmonid fishes in Europe and North America. In Europe, PKD is primarily reported affecting farmed rainbow trout Oncorhynchus mykiss, but limited information exists on the occurrence and effects of T. bryosalmonae in wild salmonids.

The Parasitic Dinoflagellates Blastodinium spp. Inhabiting the Gut of Marine, Planktonic Copepods: Morphology, Ecology, and Unrecognized Species Diversity.

Blastodinium is a genus of dinoflagellates that live as parasites in the gut of marine, planktonic copepods in the World's oceans and coastal waters. The taxonomy, phylogeny, and physiology of the genus have only been explored to a limited degree and, based on recent investigations, we hypothesize that the morphological and genetic diversity within this genus may be considerably larger than presently recognized. To address these issues, we obtained 18S rDNA and ITS gene sequences for Blastodinium specimens of different geographical origins, including representatives of the type species.

Microhabitat preference of Anisakis simplex in three salmonid species: immunological implications.

Three salmonid fish species, Oncorhynchus mykiss, Salmo salar and Salmo trutta, were infected experimentally with the parasitic nematode Anisakis simplex (A. simplex) and the difference between in vivo behaviour of the nematode in the three fish species was investigated. Infection success rate differed between species.

Myxobolus groenlandicus n. sp. (Myxozoa) distorting skeletal structures and musculature of Greenland halibut Reinhardtius hippoglossoides (Teleostei: Pleuronectidae).

A specimen of Greenland halibut Reinhardtius hippoglossoides (Walbaum, 1792) caught on the west coast of Greenland (Qasigiannguit) was found to possess serious pathological changes in the body musculature. A series of cartilaginous cylindrical structures organized symmetrically at the position of the proximal pterygiophores had changed the musculature and produced irreversible distortions (cavities and holes) in the fillet of the processed fish, leaving it with no value for the industry. Histopathological investigation showed that these structures consisted of hypertrophic cartilage containing numerous myxospore-producing plasmodia.

Ribosomal RNA gene sequences confirm that protistan endoparasite of larval cod Gadus morhua is Ichthyodinium sp.

An enigmatic protistan endoparasite found in eggs and larvae of cod Gadus morhua and turbot Psetta maxima was isolated from Baltic cod larvae, and DNA was extracted for sequencing of the parasite's small subunit ribosomal RNA (SSU rRNA) gene. The endoparasite has previously been suggested to be related to Ichthyodinium chabelardi, a dinoflagellate-like protist that parasitizes yolk sacs of embryos and larvae of a variety of fish species. Comparison of a 1535 bp long fragment of the SSU rRNA gene of the cod endoparasite showed absolute identity with I.

Identifying the lethal fish egg parasite Ichthyodinium chabelardi as a member of Marine Alveolate Group I.

Cells of the parasitic, unicellular eukaryote Ichthyodinium chabelardi were isolated from eggs of sardine (Sardina pilchardus) and from a previously unrecognized host, bogue (Boops boops), off the Atlantic coast of Portugal. Immediately after release from the infected fish egg or newly hatched larva, I. chabelardi cells were spherical and non-motile.

Identity and systematic position of Paradinium poucheti and other Paradinium-like parasites of marine copepods based on morphology and nuclear-encoded SSU rDNA.

Paradinium and Paradinium-like parasites were detected in various copepod hosts collected in the NW Mediterranean Sea, the North Atlantic Ocean, and the Godthåbsfjord (Greenland). The identity and systematic position of the parasitic, plasmodial protist Paradinium was investigated on the basis of SSU rDNA and morphology. SSU rDNA sequences were obtained from 3 specimens of Paradinium poucheti isolated from their cyclopoid copepod host, Oithona similis.

Phylogenetic position of the copepod-infesting parasite Syndinium turbo (Dinoflagellata, Syndinea).

Sequences were determined for the nuclear-encoded small subunit (SSU) rRNA and 5.8S rRNA genes as well as the internal transcribed spacers ITS1 and ITS2 of the parasitic dinoflagellate genus Syndinium from two different marine copepod hosts. Syndinium developed a multicellular plasmodium inside its host and at maturity free-swimming zoospores were released.