Morphological and molecular description of Dictyocaulus xanthopygus sp. nov. (Nematoda: Trichostrongyloidea) from the Manchurian wapiti Cervus elaphus xanthopygus.

Dictyocaulus xanthopygus sp. nov. (Nematoda: Trichostrongyloidea) was isolated from the lungs of the Manchurian wapiti in Primorsky kray, Russia. The newly described species exhibits morphological characteristics of Dictyocaulus but is distinct from congeneric species based on morphological (lengths of body and esophagus, distances from the anterior end to nerve ring and to excretory pore, the thickness of the buccal capsule, etc.) and molecular features. High levels of genetic divergence as well as Bayesian phylogenetic analyses based on 18S rRNA nuclear and cox1 mitochondrial genes supported the independence of Dictyocaulus xanthopygus sp. nov. Secondary structures of helix 39 of 18S rRNA were identical, while ES9 adjacent to the helix has a unique conformation for newly described worms. Energy-efficient conformational rearrangements of rRNA secondary structures can be applicable in studies on the pathogenesis, epidemiology, taxonomy and evolutionary biology of parasites. Additionally, bracketed dichotomous keys to six valid species of Dictyocaulus were prepared.

Integrative approach for discovering of the new species within the genus Allocreadium Looss, 1900 (Trematoda: Allocreadiidae) and framing of biogeographical hypotheses for the genus.

In July 2012 new Allocreadium species was isolated from Carassius gibelio caught in the Arsenyevka River, Primorsky region, Russia. Analyses on the morphometrics and internal organs' topology revealed that these worms are morphologically closest with A. isoporum but both species are independent according to high genetic distances based on the 28S gene fragment (5.434±0.0073%). Unlike A. isoporum found earlier in Europe, the new species named A. pseudoisoporum sp. nov. has a shorter body length and the vitellarium not reaching the posterior end of the body at some distance and its anterior border is on the level of the ventral sucker. Allocreadium pseudoisoporum sp. nov. differs from seven species previously found in the Russian Far East with the following features: smaller size of the body, suckers' ratio, range values, and topology of internal structures. Newly localities in the Pavlovka River and the Artyomovka River were discovered for A. khankaiensis. Morphological variability of the worms from the Pavlovka River was observed in comparison with A. khankaiensis from the Komissarovka River. Using scanning electron microscope, we examined external surfaces of three species (A. pseudoisoporum sp. nov., A. khankaiensis, A. hemibarbi) and observed structures reminiscent sensory receptors. This study was aimed to describe species diversity of allocreadiids inhabiting the south of Primorsky region, and to clarify phylogenetic relationships between the species from the genus Allocreadium Looss, 1900 using molecular genetic methods. The phylogenetic Bayesian tree based on the 28S gene showed a clear separation of ten Allocreadium species and confirmed the validity of A. pseudoisoporum sp. nov. Allocreadium pseudoisoporum sp. nov. is most similar to A. gotoi (genetic distances - 3.578±0.0051% in 28S, and 18.777±0.0149% in cox1), and represented the earliest divergent lineage in Allocreadium clade on the phylogenetic tree based on the 28S gene, thereby indicating its proximity to the ancestral node. Also, dichotomous keys for 25 Palearctic species of Allocreadium were prepared based on the morphology of the adult worms.

Molecular identification of the trematode P. ichunensis stat. n. from lungs of siberian tigers justified reappraisal of Paragonimus westermani species complex.

Flukes from the genus Paragonimus Braun, 1899 are medically important foodborne trematodes predominantly occurring throughout Asian countries. Providing molecular genetic characteristics based on ITS2 and partial 28 S rDNA of the paragonimids from the Russian Far East, Northeast, South, and Southeast Asian countries, we performed a partial reappraisal of Paragonimus westermani species complex. Members of this complex are genetically distinct worms with different divergence times and explosive expansion during Miocene-Pliocene epochs. We confirm the taxonomic status as valid species for P. ichunensis stat. n. (from the Russian Far East and Northern China), and P. filipinus (from the Philippines), which were previously considered subspecies of P. westermani, and reinstated the species name P. pulmonalis (from Japan). We suggest considering the worms from South Korea the Korean variety of P. ichunensis, because Korean specimens are sister and genetically closest to P. ichunensis from Northeast China and Primorsky region of Russia. Worms from South (India (type 2), Sri Lanka), Southeast (Malaysia, Vietnam, Thailand (types 1 and 2)) and East Asia (Taiwan) were left in the paragonimid systematics as Paragonimus sp. We propose to consider Indian worms of type 1 as true P. westermani, but in further revisions, due to the lack of holotype and unknown exact type locality, new type specimens (neotype) should be established.

Origins, phylogenetic relationships and host-parasite interactions of Troglotrematoidea since the cretaceous.

In the current study, we raise the issue concerning origins and historical relationships of the trematodes from the families Troglotrematidae and Paragonimidae using phylogenetic analysis and molecular-clock method for estimating evolutionary rates. For the first time we provided 28S rRNA gene fragment (1764 bp) for the type species Troglotrema acutum - zoonotic trematodes that cause cranial lesions (troglotremiasis) in mustelid and canid mammals of the Central Europe, Iberian Peninsula, and North-West Caucasus. Molecular genetic analysis revealed that T. acutum belongs to the monophyletic family Troglotrematidae sister with the family Paragonimidae. The family Troglotrematidae includes five genera: Nanophyetus, Troglotrema, Skrjabinophyetus, Nephrotrema, and Macroorchis; and the family Paragonimidae is monotypic including the only genus Paragonimus. We recover the superfamily Troglotrematoidea for these two families. Divergence of the common ancestor of the superfamily Troglotrematoidea (common troglotrematoid ancestor) likely occurred during the Cretaceous period of the Mesozoic Era and potentially originated in the Asiatic region. The lineage of the family Troglotrematidae is much closer to the common troglotrematoid ancestor than the species of the family Paragonimidae. The radiation time of the common troglotrematoid ancestor (126 Ma, the Early Cretaceous), and formation of the families Troglotrematidae and Paragonimidae (96 Ma and 73 Ma respectively, the Late Cretaceous) corresponds to the time of settling in East Asia by many species of mammaliaforms (about 130-70 Ma).

Antiparasitic Effects of Sulfated Polysaccharides from Marine Hydrobionts.

This review presents materials characterizing sulfated polysaccharides (SPS) of marine hydrobionts (algae and invertebrates) as potential means for the prevention and treatment of protozoa and helminthiasis. The authors have summarized the literature on the pathogenetic targets of protozoa on the host cells and on the antiparasitic potential of polysaccharides from red, brown and green algae as well as certain marine invertebrates. Information about the mechanisms of action of these unique compounds in diseases caused by protozoa has also been summarized. SPS is distinguished by high antiparasitic activity, good solubility and an almost complete absence of toxicity. In the long term, this allows for the consideration of these compounds as effective and attractive candidates on which to base drugs, biologically active food additives and functional food products with antiparasitic activity.

Systematics of Crepidostomum species from the Russian Far East and northern Japan, with description of a new species and validation of the genus Stephanophiala.

Current article touched upon the issue of the complicated taxonomic status of some species from the genus Crepidostomum collected from the freshwater fish in the rivers of Primorsky region, Sakhalin, and Hokkaido Islands. Primary morphological analyses showed affiliation of the worms to the species C. farionis (Müller, 1784) Lühe, 1909; C. metoecus Braun, 1900b; C. chaenogobii Yamaguti and Matsumura, 1942; C. nemachilus Krotov, 1959. We described the new species Crepidostomum achmerovi sp. nov. that is a sibling species of C. nemachilus. Molecular-genetic investigation have shown that C. nemachilus and C. achmerovi sp. nov. are closely related to C. metoecus in both 28S rDNA and cox1 mtDNA markers. Crepidostomum nemachilus forms a separate branch within the C. metoecus clade on the 28S BI tree with strong statistical support and separate clade in relation to C. metoecus clade on the cox1 BI tree. Values of p-distances between Crepidostomum species were at intergeneric level. Crepidostomum metoecus species complex including five species (C. metoecus, C. nemachilus, C. oschmarini, C. brinkmanni, and C. achmerovi sp. nov.) was reconsidered as independent genus Crepidostomum sensu stricto. Minimum Spanning Network showed that C. nemachilus, C. metoecus and C. achmerovi sp. nov. were separated by large number of mutational events and represent independent phyletic lines. An amended diagnosis is provided for the subfamily Crepidostomatinae, the genera Crepidostomum s. str. and Stephanophiala Nicoll, 1909, along with keys to species of both genera.

First report on molecular identification of Anisakis simplex in Oncorhynchus nerka from the fish market, with taxonomical issues within Anisakidae.

Alive anisakids cause acute gastrointestinal diseases, and dead worms contained in food can provoke sensibilization and allergic reactions in humans. Detected in the purchased minced salmon Oncorhynchus nerka nematodes were identified as Anisakis simplex sensu stricto (Anisakidae). We found that recently published phylogenetic trees (reconstructed using different ribosomal and mitochondrial genetic markers) showed independent clusterization of species recognized in the A. simplex sensu lato species complex. This prompted us to undertake this full-fledged molecular genetics study of anisakids from Kamchatka with phylogenetic reconstructions (NJ/ML) and calculated ranges of interspecific and intergeneric p-distances using ITS1-5.8S-ITS2 sequences. We confirmed that molecular markers based on the ITS region of rDNA were able to recognize 'pure' specimens belonging to the cryptic species. We offer new insights into the systematics of anisakids. The genus Anisakis sensu stricto should include Anisakis simplex sensu stricto, Anisakis pegreffii, Anisakis berlandi, Anisakis ziphidarum, and Anisakis nascettii. Presumably, two genera should be restored in the structure of the subfamily Anisakinae: Skrjabinisakis for the species Anisakis paggiae, Anisakis brevispiculata, and Anisakis physeteris; and Peritrachelius for the species Anisakis typica. In addition, we provide the short annotated list of some genera of the family Anisakidae, including their diagnoses.

Paragonimus heterotremus Chen et Hsia, 1964 (Digenea: Paragonimidae): species identification based on the biological and genetic criteria, and pathology of infection.

As a result of the experimental infection of rats with metacercariae of Paragonimus heterotremus Chen et Hsia, 1964 from crabs (Potamiscus tannanti) caught in Yen Bai province, Vietnam, it was found that worms migrated into the lungs, to the liver and less frequently to the tissue that lines body cavities of the hosts, where they reached the adult stage, but in the muscles, worms stayed at the larval stage. Studies have shown that for P. heterotremus, rats can simultaneously play the role of the final and paratenic host; herewith, an infection with the trematode of this species can lead to the development of three forms of paragonimiasis: pulmonary, hepatic and muscular. Eggs from the adult worms localised in the liver, unlike eggs from the adult worms localised in the lungs, were not excreted into the external environment, but accumulated inside the organ. Histology and description of changes, which take place on the external surface of organs affected with P. heterotremus, are given in this study. Based on the behavioural characteristics of worms during rat infection and molecular genetic data, we established that worms from Vietnam and India should be assigned to different species of Paragonimus. P. heterotremus distribution is limited to the territory of the Southeast China, Northern Vietnam, Laos and Thailand.

Variation in the number of nucleoli and incomplete homogenization of 18S ribosomal DNA sequences in leaf cells of the cultivated Oriental ginseng (Panax ginseng Meyer).

BACKGROUND: Wild ginseng, Panax ginseng Meyer, is an endangered species of medicinal plants. In the present study, we analyzed variations within the ribosomal DNA (rDNA) cluster to gain insight into the genetic diversity of the Oriental ginseng, P. ginseng, at artificial plant cultivation. METHODS: The roots of wild P. ginseng plants were sampled from a nonprotected natural population of the Russian Far East. The slides were prepared from leaf tissues using the squash technique for cytogenetic analysis. The 18S rDNA sequences were cloned and sequenced. The distribution of nucleotide diversity, recombination events, and interspecific phylogenies for the total 18S rDNA sequence data set was also examined. RESULTS: In mesophyll cells, mononucleolar nuclei were estimated to be dominant (75.7%), while the remaining nuclei contained two to four nucleoli. Among the analyzed 18S rDNA clones, 20% were identical to the 18S rDNA sequence of P. ginseng from Japan, and other clones differed in one to six substitutions. The nucleotide polymorphism was more expressed at the positions 440-640 bp, and distributed in variable regions, expansion segments, and conservative elements of core structure. The phylogenetic analysis confirmed conspecificity of ginseng plants cultivated in different regions, with two fixed mutations between P. ginseng and other species. CONCLUSION: This study identified the evidences of the intragenomic nucleotide polymorphism in the 18S rDNA sequences of P. ginseng. These data suggest that, in cultivated plants, the observed genome instability may influence the synthesis of biologically active compounds, which are widely used in traditional medicine.