Parasites of graylings (Thymallidae: Thymallus) from the northern continental coast of the Okhotsk Sea

For the first time, generalized data on parasites of two subspecies of arctic grayling (Thymallus arcticus pallasi and Th. a. mertensi) from the largest salmon rivers of the northern coast of the Okhotsk Sea, as the Taui, Yama and Gizhiga, are presented. In total, 39 species of parasites are found including 38 helminth species belonging to 26 genera, 19 families, 5 classes and 3 types (Plathelminthes, Nemathelminthes, and Acanthocephales), and 1 parasitic copepod (Crustacea; Arthropoda). Among the flatworms, trematodes have the highest species diversity — 19 species belonged to 8 genera of 6 families, and cestodes are presented by 6 species (6 genera of 5 families). Nematodes are presented by 8 species (8 genera of 5 families), and acanthocephalans — by 5 species (4 genera, 3 families, 2 classes). The graylings parasites are distributed with 2 ecological groups: the freshwater parasites including 29 species (4 cestodes, 16 trematodes, 5 nematodes, 3 acanthocephalans, and 1 copepod) and the marine parasites including 10 species (2 cestodes, 3 trematodes, 3 nematodes, and 2 acanthocephalans). Th. a. mertensi from the Taui River basin is distinguished by the highest diversity of parasites (32 species), their high diversity is observed for the same species from the Gizhiga (20 species), and for Th. a. pallasi from the Yama (24 species), as well. More than a half of helminths (22 species) are noted by medical and veterinary importance and/or are able to spoil organoleptic properties of the seafood.

Advances in Omic Studies Drive Discoveries in the Biology of Anisakid Nematodes

Advancements in technologies employed in high-throughput next-generation sequencing (NGS) methods are supporting the spread of studies that, combined with advances in computational biology and bioinformatics, have greatly accelerated discoveries within basic and biomedical research for many parasitic diseases. Here, we review the most updated “omic” studies performed on anisakid nematodes, a family of marine parasites that are causative agents of the fish-borne zoonosis known as anisakiasis or anisakidosis. Few deposited data on Anisakis genomes are so far available, and this still hinders the deep and highly accurate characterization of biological aspects of interest, even as several transcriptomic and proteomic studies are becoming available. These have been aimed at discovering and characterizing molecules specific to peculiar developmental parasitic stages or tissues, as well as transcripts with pathogenic potential as toxins and allergens, with a broad relevance for a better understanding of host–pathogen relationships and for the development of reliable diagnostic tools.

Parasites of the Brazilian flathead Percophis brasiliensis reflect West Atlantic biogeographic regions

SUMMARYWith the aim of evaluating the utility of marine parasites as indicators of zoogeographical regions in the South West Atlantic, we analyzed data on assemblages of long-lived larval parasites of 488 specimens of Percophis brasiliensis distributed in 11 samples from nine localities covering the entire distribution of the species in the Argentine biogeographical Province. Near half a million long-lived parasite individuals belonging to 17 species present in the whole sample displayed clear latitudinal patterns. Data for parasite assemblages at infracommunity and component community levels were analysed in relation to the geographical distance. Significant similarity decay of parasite assemblages over distance was observed, with those based on abundances and mean abundances showing departures from predicted values of regressions. These departures were represented by higher dissimilarities between samples coming from different zoogeographical regions than between those caught within the same region, independently of the distance separating them. Consequently, zoogeographical regions were identified in a distance-decay context. Multivariate analyses corroborated a close fit of similarity between assemblages to existing zoogeographical classifications. Regressions representing distance decay of similarity, and the identification of their outliers, can therefore shed light on the existence of discontinuities or uniformities in the geographic distribution of parasite assemblages and, in turn, in the zoogeography of their fish hosts.

The electronic collection of the World Ocean fish parasites maintained by Kovalevsky Institute of Marine Biological Research RAS

Biological collections are the basis for taxonomic research and study of the regional biodiversity. The aims of this work are the creation of an electronic catalogue of collection specimens and taxonomic database (DB), as well as the development of a web resource to access them, for integrating biological collections in the research process. The IMBR Collection of Marine Parasites is used as material for this site. The PHP and JavaScript programming languages are used for its creation and the relation database management system MYSQL is used for manage database. The website and database are operated by the Apache webserver. Website marineparasites.org includes the electronic catalog of the collection, the taxonomic database and the repository of publications about species of fish parasites. The website provides an interactive interface to access the above listed resources. The functioning of the website is based on four entities related to each other: a collection object, specimens, taxa, and publication. Each entity corresponds to a database table. During filling the tables, the system automatically creates connections between collection samples, their type and taxonomic status and other attributes. Visitors of the site can make requests using filters and get a complete representation on the collection. Webpage of taxon consists of the data on the species systematic position and its synonyms. Indicator of the presence of samples of the species in the collection, a list of attributes of collection exemplars, publications that mention this species, type locality and host of the parasite as well as other regions and hosts of its finding, description and images are located on the page of the parasite species. Thus, the user follows from the descriptions of the parasite species to their hosts, from the collection samples to their images and taxonomic diagnosis, publications on this parasite and inversely. English language of interface facilitates that more researchers can obtain information on the collection of marine parasites maintained by Institute of Marine Biological Research RAS and helps to integrate it into the international web resources on biodiversity. The site reports specific information to professional researchers of parasites, but ideas it is based on allow to develop it into a resource on collections of any organisms and diversity of flora and fauna of any regions. The site is the result of fruitful cooperation between biologists and programmers; it promotes the intensification of exchange of collection data and samples, and is a tool for studying parasite components of marine communities. Project is supported by Russian Foundation for Basic Research, Grant No 15-29-02684 ofi-m.