TREMATODE SPECIES DETECTION AND QUANTIFICATION BY ENVIRONMENTAL DNA-qPCR ASSAY IN LAKE CHANY, RUSSIA.

Environmental DNA (eDNA) surveys promise to be a sensitive and powerful tool for the detection of trematodes. This can contribute to the limited studies on trematode ecology, specifically in aquatic ecosystems. Here, we developed species-specific primer and probe sets for Moliniella anceps, Opisthioglyphe ranae, and Plagiorchis multiglandularis cercariae and applied a novel eDNA qPCR assay to detect larval trematodes quantitatively. We evaluated the effectiveness of the assays using filtered lake water samples collected from different sites of Lake Fadikha and Kargat River Estuary in Lake Chany, Russia, showing high species specificity and sensitivity in all 3 assays. Further, all 3 assays had high efficiencies ranging from 94.9 to 105.8%. Moliniella anceps, O. ranae, and P. multiglandularis were detected in the environmental water samples through real-time PCR. Thus, we anticipate that our approach will be beneficial for biomonitoring, measuring, and managing ecological systems.

Characterization of the complete mitochondrial genome of Plagiorchis multiglandularis (Digenea, Plagiorchiidae): Comparison with the members of Xiphidiatan species and phylogenetic implications.

Plagiorchis multiglandularis Semenov, 1927 is a common fluke of birds and mammals, with significant impacts on animals and also human health. However, the systematics of Plagiorchiidae remain ambiguous. In the present study, the complete mitochondrial (mt) genome of P. multiglandularis cercariae was sequenced and compared with other digeneans in the order Xiphidiata. The complete circular mt genome of P. multiglandularis was 14,228 bp in length. The mitogenome contains 12 protein-coding genes and 22 transfer RNA genes. The 3' end of nad4L overlaps the 5' end of nad4 by 40 bp, while the atp8 gene is absent. Twenty-one transfer RNA genes transcribe products with conventional cloverleaf structures, while one transfer RNA gene has unpaired D-arms. Comparative analysis with related digenean trematodes revealed that A + T content of mt genome of P. multiglandularis was significantly higher among all the xiphidiatan trematodes. Phylogenetic analyses demonstrated that Plagiorchiidae formed a monophyletic branch, in which Plagiorchiidae are more closely related to Paragonimidae than Prosthogonimidae. Our data enhanced the Plagiorchis mt genome database and provides molecular resources for further studies of Plagiorchiidae taxonomy, population genetics and systematics.

The complete mitogenome of Echinoparyphium aconiatum (Digenea: Echinostomatidae) and a comparison with other digenean species.

Echinoparyphium aconiatum (Digenea: Echinostomatidae) is an intestinal parasite of anatid and snail-eating birds. In Eurasia, it is also common in lymnaeid snails, which may serve as the first and second intermediate hosts. The systematics of its genus, Echinoparyphium, have long been inadequate, with poor descriptions and extensive synonymy. To provide a basis for developing new genetic markers for studies of the identification and systematics of echinostomatids, the complete Ep. aconiatum mitogenome is described and compared with other digeneans. The circular mt molecule of this species is 14,865 bp in length, with an average A + T content of 64.33%. It contains 12 protein-coding genes and 22 transfer RNA genes. The 3' end of nad4L overlaps the 5' end of nad4 by 40 bp, while the atp8 gene is absent. Twenty-one transfer RNA genes transcribe products with conventional cloverleaf structures, while one transfer RNA gene has unpaired D-arms. Comparative analyses indicate that Echinoparyphium aconiatum is closely related to Echinochasmus japonicus and Echinostoma miyagawai. The phylogenetic results, using our mitochondrial data indicated Ep. aconiatum as a sister taxon of Hypoderaeum conoideum in a monophyletic clade. Our data and analyses serve as the first representative sequenced mt genome from genus Echinoparpyhium, providing additional markers to clarify the taxonomic position of Ep. aconiatum.