Identification of specific molecular markers for spermatogonial stem cells in teleost is crucial for enhancing the efficacy of reproductive biotechnologies in aquaculture, such as transplantation and surrogate production in fishes. Since it is not yet possible to distinguish spermatogonial stem cells of European eel (Anguilla anguilla) using specific molecular markers, we isolated spermatogonial cells from immature European eels to find these potential markers. We attempted this by studying three candidate genes: vasa, nanos2, and dnd1. Two vasa (vasa1 and vasa2) genes, nanos2, and dnd1 were identified, characterized, and studied in the muscle, testis, and isolated spermatogonia. Our results showed that vasa1 and vasa2 had the highest levels of expression when measured by qPCR. In situ hybridization and immunochemistry assays showed that the four genes were localized explicitly in type A spermatogonia. However, vasa1 and vasa2 exhibited stronger signals in the immature testicular tissue than the other two potential markers. According to this, vasa1 and vasa2 were found to be the most effective markers for spermatogonial cells in the European eel.

• Klíčová slova
• Dnd1, Nanos2, Vasa, Fish, Gene expression, Testis,
• MeSH
• Anguilla * genetika   MeSH
• biologické markery * metabolismus   MeSH
• proteiny vázající RNA genetika   metabolismus   MeSH
• rybí proteiny genetika   MeSH
• spermatogonie * metabolismus   MeSH
• testis * metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biologické markery * MeSH
• proteiny vázající RNA MeSH
• rybí proteiny MeSH

European eel, Anguilla anguilla (Linnaeus) (Elopomorpha: Anguilliformes), is a critically endangered fish of ecological and economic importance, hosting numerous parasites, including myxozoans (Cnidaria). Since its initial discovery in the kidney of European eel, Myxidium giardi Cépède, 1906 has been reported with numerous spore sizes and shapes from various tissues of multiple anguillid species. Morphological variability, wide host and tissue spectrum, and lack of sequence data raised doubts about the conspecificity of reported isolates. Subsequent studies provided 18S rDNA sequences of several isolates from anguillids and other elopiform fish, and demonstrated a split of parasite data into two distinct phylogenetic lineages, one comprising the M. giardi sequence, and the other all species infecting elopiform fishes classified under the recently established genus Paramyxidium Freeman et Kristmundsson, 2018. Myxidium giardi was, however, transferred to this genus as Paramyxidium giardi n. comb. and designated as the type species of the genus. In line with this change, the sequence originally identified as M. giardi was considered to have been incorrectly associated with this species. To shed light on the status of M. giardi originally described by Cépède (1906), we conducted microscopic and molecular examinations of various organs of 24 individuals of European eel, originating from diverse Czech habitats. Through morphometric and molecular analyses, we demonstrated that spore and polar capsule morphology, morphometry and tissue tropism of our European eel kidney parasite isolates matched the features of the original M. giardi description. Our isolates clustered in the lineage encompassing the first published M. giardi sequence. Thus, the originally described M. giardi indeed represents an existing species within the genus Myxidium Bütschli, 1882, which we formally resurrect and redescribe. Due to the morphological and molecular differences between M. giardi and P. giardi of Freeman et Kristmundsson (2018), we additionally rename the latter species as Paramyxidium freemani nom. nov.

• Klíčová slova
• Anguilla, Myxozoa, PCR screening., phylogeny, taxonomy,
• MeSH
• Anguilla * parazitologie   MeSH
• fylogeneze * MeSH
• ledviny * parazitologie   MeSH
• Myxozoa * klasifikace   genetika   fyziologie   MeSH
• nemoci ryb * parazitologie   MeSH
• parazitární nemoci u zvířat * parazitologie   MeSH
• RNA ribozomální 18S analýza   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• RNA ribozomální 18S MeSH

OBJECTIVE: Feed additives have attracted increased attention in aquaculture due to their ability to modulate fish gut microbiota, resulting in improved fish growth and immunity. This study assessed the effects of two synbiotics in Japanese Eel Anguilla japonica: Bacillus subtilis with mannooligosaccharides (MOS) and Enterococcus faecium with fructooligosaccharides (FOS). METHODS: Six diets, including a control (CON) diet, oxytetracycline (OTC) diet, and four synbiotic diets (B. subtilis at 1 × 106 or 1 × 107 colony-forming units [CFU]/g with MOS at 5 g/kg [BS6MO and BS7MO; collectively, BSMOS diets] and E. faecium at 1 × 106 or 1 × 107 CFU/g with FOS at 5 g/kg [EF6FO and EF7FO; collectively, EFFOS diets]), were fed to triplicate groups of 20 fish (average weight ± SD = 6.00 ± 0.07 g) for 8 weeks. RESULT: Fish fed the BSMOS diets showed significantly higher weight gain, specific growth rate (SGR), and feed efficiency compared to fish fed the CON and OTC diets, but the values were not significantly different from those of fish fed the EFFOS diets. Weight gain and SGR of fish that were given EFFOS diets were not significantly different from those of fish fed all other diets. Fish fed the OTC diet showed a higher mean aspartate aminotransferase level, although the difference was not statistically significant. The myeloperoxidase activity of fish fed the BS7MO diet was significantly higher than those of fish receiving all other diets, and the superoxide dismutase activity of fish fed the BS7MO diet was also significantly higher than that of fish fed the EF7FO diet. Overall, the BSMOS synbiotic diets were significantly more effective than the CON diet in enhancing fish survival against a Vibrio anguillarum challenge. CONCLUSION: Our findings suggest that synbiotics can be a preferable alternative to antibiotics in aquaculture.

• Klíčová slova
• antibiotics, feed additives, fish diseases, immune response, probiotics,
• MeSH
• Anguilla růst a vývoj   MeSH
• Bacillus subtilis MeSH
• dieta * veterinární   MeSH
• Enterococcus faecium MeSH
• krmivo pro zvířata * analýza   MeSH
• oligosacharidy aplikace a dávkování   farmakologie   MeSH
• přirozená imunita účinky léků   MeSH
• synbiotika * aplikace a dávkování   MeSH
• vodní hospodářství metody   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie veterinární MeSH
• Názvy látek
• oligosacharidy MeSH

In recent years, an emerging dermocystidiosis caused by Dermocystidium anguillae Spangenberg, 1975 has been found to pose a threat to the culture of American eel, Anguilla rostrata (Lesueur), as well as Chinese perch, Siniperca chuatsi (Basilewsky), in China. Dermocystidium anguillae was originally described from European eel, Anguilla anguilla (Linnaeus), and it is thus important to identify the possible source of this pathogen. In the present study, we compared D. anguillae from European eels cultured in China with those from American eels. Molecular analysis showed that the SSU rDNA of D. anguillae infecting European eels was identical to that of D. anguillae infecting American eels, suggesting their conspecificity. To investigate the source of D. anguillae causing dermocystidiosis in American eels cultured in China, a specific PCR assay for the detection of D. anguillae was developed with high sensitivity (10-6 ng/µl of D. anguillae genomic DNA). Using the present molecular detection method, the water and sediment of culture ponds, fish feed and American eel elvers imported from America were screened for the presence of D. anguillae. No amplicons were detected from the water, sediment and fish feed samples. However, positive amplicons were found in American eel elvers, indicating that D. anguillae has been introduced from American eel elvers to China. It is suggested that American eel elvers imported from America should be examined for the presence of D. anguillae before their exportation abroad to prevent the spread of this pathogen.

• Klíčová slova
• Anguillidae, Mesomycetozoea, dermocystidiosis, diagnosis, species identification,
• MeSH
• Anguilla * MeSH
• voda MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Čína epidemiologie   MeSH
• Názvy látek
• voda MeSH

Infection of non-indigenous pumpkinseed (Lepomis gibbosus, Centrarchidae) with the bothriocephalidean cestode Bothriocephalus claviceps (Cestoda: Bothriocephalidae) was confirmed at several sites in the lower Oder river basin in Poland. The preferred host for this cestode species is the European eel (Anguilla anguilla), with a wide range of other fish species serving as paratenic hosts. The pumpkinseed showed a relatively high prevalence and abundance of larvae, along with several mature and gravid specimens, thereby confirming development of B. claviceps to the adult stage in an alternative host. As such, the pumpkinseed may represent an additional definitive host for this cestode, in addition to its role as a paratenic host, as previously recorded in other European regions. Our results indicate that inclusion of pumpkinseed as an additional definitive host in the cestode's life cycle, high infection of pumpkinseed with B. claviceps larvae and inclusion of pumpkinseed in the eel's diet could potentially lead to increased parasite pressure on native fish hosts. Further comparative studies or experimental testing will be required to confirm this.

• Klíčová slova
• Aquatic invasions, Cestode, Host-parasite interaction, Oder river basin, Pumpkinseed,
• MeSH
• Anguilla MeSH
• Cestoda * růst a vývoj   MeSH
• nemoci ryb * parazitologie   MeSH
• Perciformes * parazitologie   MeSH
• stadia vývoje MeSH
• zavlečené druhy MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH

Invasive non-native species have pervasive impacts on native biodiversity, including population extirpations and species extinctions. Identifying reasons why a population of a native species is extirpated following an invasion often relies on literature-based results of anecdotal observations. The well-established schemes of existing risk assessments for invasive species assume that a species' information (e.g. impacts or behavioural and biological traits) can be projected from one area to another to estimate the potential impact of a species in another environment. We used stable isotope data (δ13C, δ15N) from both invaded and uninvaded communities to predict such invasion impacts by reconstructing trophic relationships. This approach was tested on a community within a protected lake in Northern Spain where, following the introductions of non-native species, the last resident native species (the common tench Tinca tinca, the European eel Anguilla anguilla, and the whirligig beetle Gyrinus sp.) had been extirpated. Through the application of this novel approach, we found evidence that native species' declines were related to direct predation by and resource overlap with non-native species, which occurred in conjunction with habitat modification. Using this approach, we outlined the mechanisms involved in the extirpation of native species in the post-invasion period. To compensate for losses of native species induced by invasions of non-native species, native species reintroductions might be an appropriate tool. For this, we further suggested and discussed a novel approach that predicts the outcome of arising interactions by superimposing stable isotope data from alternative sources to better estimate the success of native species´ reintroductions.

• MeSH
• Anguilla * MeSH
• biodiverzita * MeSH
• Cyprinidae * MeSH
• ekosystém * MeSH
• extinkce biologická * MeSH
• izotopy * MeSH
• zachování přírodních zdrojů metody   MeSH
• zavlečené druhy * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Španělsko MeSH
• Názvy látek
• izotopy * MeSH

Recent occasional examinations of two species of eels (Anguilliformes: Anguillidae) in Japan, the Japanese eel Anguilla japonica Temminck & Schlegel from central Japan and the giant mottled eel Anguilla marmorata Quoy & Gaimard from southern Japan, respectively, revealed the following four species of gastrointestinal parasitic nematodes: Cucullanus filiformis Yamaguti, 1935 (Cucullanidae) from A. japonica; Paraquimperia japonica n. sp. (Quimperiidae) from A. japonica (type-host) and A. marmorata; Heliconema anguillae Yamaguti, 1935 (Physalopteridae) from A. marmorata (new host record); and Spinitectus anguillae n. sp. (Cystidicolidae) from A. japonica (type-host) and A. marmorata. Specimens of all species are described based on light and scanning electron microscopical examinations. Paraquimperia japonica n. sp. is mainly characterised by the presence of a ventral sucker, spicules 210-231 µm long and by narrow cervical alae, whereas S. anguillae n. sp. by the number (29-36) of cuticular spines in the first ring, the length of the left spicule (351 µm) and the structure (without polar caps, filaments or lateral swellings), and the size of eggs (36-42 × 21-27 µm).

• MeSH
• Anguilla parazitologie   MeSH
• druhová specificita MeSH
• hlístice klasifikace   ultrastruktura   MeSH
• mikroskopie elektronová rastrovací MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Japonsko MeSH

Casualties caused by nerve agents, potent acetylcholinesterase inhibitors, have attracted attention from media recently. Poisoning with these chemicals may be fatal if not correctly addressed. Therefore, research on novel antidotes is clearly warranted. Pyridinium oximes are the only clinically available compounds, but poor penetration into the blood-brain barrier hampers efficient enzyme reactivation at the central nervous system. In searching for structural factors that may be explored in SAR studies, we synthesized and evaluated neutral aryloximes as reactivators for acetylcholinesterase inhibited by NEMP, a VX surrogate. Although few tested compounds reached comparable reactivation results with clinical standards, they may be considered as leads for further optimization.

• Klíčová slova
• Acetylcholinesterase reactivators, Chemical defence, Drug screening, Nerve agents' surrogates, Neutral oximes,
• MeSH
• acetylcholinesterasa chemie   metabolismus   MeSH
• Anguilliformes MeSH
• antidota chemická syntéza   metabolismus   MeSH
• cholinesterasové inhibitory chemie   metabolismus   MeSH
• organothiofosforové sloučeniny chemie   metabolismus   MeSH
• oximy chemie   metabolismus   MeSH
• pyrrolidiny chemie   metabolismus   MeSH
• reaktivátory cholinesterasy chemická syntéza   metabolismus   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• antidota MeSH
• cholinesterasové inhibitory MeSH
• N-ethylmercapto-3-4-dihydroxy-2-hydroxymethylpyrrolidine MeSH Prohlížeč
• organothiofosforové sloučeniny MeSH
• oximy MeSH
• pyrrolidiny MeSH
• reaktivátory cholinesterasy MeSH
• VX MeSH Prohlížeč

Collections of parasitic nematodes of fishes from some freshwater and brackish-water localities in Honshu, Shikoku and Hokkaido, Japan, carried out in 1996-2009, yielded the following eight species: Hysterothylacium haze (Machida, Takahashi et Masuuchi, 1978) (Anisakidae), Paraquimperia sp., Pingus sinensis Hsü, 1933 (both Quimperiidae), Heliconema anguillae Yamaguti, 1935 (Physalopteridae), Rhabdochona angusticaudata sp. n., Rhabdochona zacconis Yamaguti, 1935 (both Rhabdochonidae), Ascarophis arctica Polyanskiy, 1952 (Cystidicolidae) and Eustrongylides sp. larvae (Dioctophymatidae). The new species, R. angusticaudata sp. n., described from the intestine of the Japanese eel Anguilla japonica Temminck et Schlegel in the Renjoji River, Shikoku, is mainly characterised by the presence of 14-16 anterior prostomal teeth, non-bifurcated deirids with rounded ends, the length of the left spicule (300-384 µm long), the right spicule with a dorsal barb and non-filamented eggs. The species of Paraquimperia Baylis, 1934 and A. arctica are reported from Japan for the first time. Based on light and scanning electron microscopical examinations, some new morphological data on H. haze, H. anguillae, R. zacconis and A. arctica are provided.

• Klíčová slova
• Ascarophis, Heliconema, Hokkaido, Honshu, Hysterothylacium, Paraquimperia, Pingus, Shikoku, freshwater fish, parasitic nematode,
• MeSH
• Anguilla * MeSH
• Ascaridida fyziologie   MeSH
• infekce hlísticemi řádu Ascaridida epidemiologie   parazitologie   veterinární   MeSH
• infekce hlísticemi řádu Spirurida epidemiologie   parazitologie   veterinární   MeSH
• nemoci ryb epidemiologie   parazitologie   MeSH
• prevalence MeSH
• rozšíření zvířat * MeSH
• ryby MeSH
• Spiruroidea fyziologie   MeSH
• Thelazioidea fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Japonsko epidemiologie   MeSH

Based on light and scanning electron microscopical studies of nematode specimens from the digestive tract of some rarely collected anguilliform and perciform fishes off New Caledonia, three new species of Cucullanus Müller, 1777 (Cucullanidae) are described: C. austropacificus n. sp. from the longfin African conger Conger cinereus (Congridae), C. gymnothoracis n. sp. from the lipspot moray Gymnothorax chilospilus (Muraenidae), and C. incognitus n. sp. from the seabream Dentex fourmanoiri (Sparidae). Cucullanus austropacificus n. sp. is characterized by the presence of cervical alae, ventral sucker, alate spicules 1.30-1.65 mm long, conspicuous outgrowths of the anterior and posterior cloacal lips and by elongate-oval eggs measuring 89-108 × 48-57 μm; C. gymnothoracis n. sp. is similar to the foregoing species, but differs from it in the absence of cervical alae and the posterior cloacal outgrowth, in the shape and size of the anterior cloacal outgrowth and somewhat shorter spicules 1.12 mm long; C. incognitus n. sp. (based on female morphology) differs from other congeneric species parasitic in the Sparidae mainly in possessing cervical alae, the postequatorial vulva, phasmids situated at the mid-length of the tail and in the size of the eggs (75-84 × 45-66 μm). A key to species of Cucullanus parasitizing anguilliform fishes is provided.

TITLE: Trois nouvelles espèces de Cucullanus (Nematoda: Cucullanidae) de poissons marins au large de la Nouvelle-Calédonie, avec une clé des espèces de Cucullanus d’Anguilliformes. ABSTRACT: Sur la base d’une étude en microscopie photonique et électronique à balayage de spécimens de nématodes provenant du tube digestif de quelques poissons anguilliformes et perciformes rarement pêchés en Nouvelle-Calédonie, trois nouvelles espèces de Cucullanus Müller, 1777 (Cucullanidae) sont décrites : C. austropacificus n. sp. de Conger cinereus (Congridae), C. gymnothoracis n. sp. de Gymnothorax chilospilus (Muraenidae) et C. incognitus n. sp. de Dentex fourmanoiri (Sparidae). Cucullanus austropacificus n. sp. est caractérisé par la présence d’ailes cervicales, une ventouse ventrale, des spicules ailés de 1,30-1,65 mm de long, des excroissances remarquables des lèvres cloacales antérieure et postérieure et d’oeufs ovales et allongés mesurant 89-108 × 48-57 μm. C. gymnothoracis n. sp. est semblable à l’espèce précédente, mais en diffère en l’absence d’ailes cervicales et d’excroissance cloacale postérieure, par la forme et la taille de l’excroissance cloacale antérieure et par des spicules un peu plus courts de 1,12 mm. C. incognitus n. sp. (basé sur la morphologie de la femelle) diffère des autres espèces congénères parasites chez les Sparidae principalement par la possession d’ailes cervicales, une vulve postéquatoriale, des phasmides situés à mi-longueur de la queue et par la taille des oeufs (75–84 × 45–66 μm). Une clé des espèces de Cucullanus parasitant les poissons anguilliformes est fournie.

• MeSH
• Anguilliformes parazitologie   MeSH
• gastrointestinální trakt parazitologie   MeSH
• hlístice anatomie a histologie   klasifikace   genetika   izolace a purifikace   MeSH
• kloaka parazitologie   MeSH
• mikroskopie elektronová rastrovací veterinární   MeSH
• mikroskopie MeSH
• nematodózy epidemiologie   parazitologie   veterinární   MeSH
• nemoci ryb epidemiologie   parazitologie   MeSH
• Perciformes parazitologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Nová Kaledonie epidemiologie   MeSH