In this work, the wound healing potential of the extract from plerocercoids of gulltapeworm D. dendriticus was first estimated in the mouse full-thickness wound model. Both the evaluation of wound closure rate and the histological characteristics of the healing process were performed. In the course of the study, the effect of the extract on contraction and epithelization of wound was not revealed. At the same time, the results of histological analysis showed that the epidermis in the group of mice whose wounds were treated with the extract was less differentiated, and the newly formed connective tissue was less mature than in the group of control animals. In addition, differences were found in the composition of leukocyte infiltrate in the granulation tissue of experimental animals – there was a significant increase in the number of eosinophils and a tendency to a lower content of neutrophils. The results obtained indicate that treatment of wounds with extract from plerocercoids slows down the reparative processes, which, however, does not lead to significant changes in the rate of wound contraction. Perhaps, this difference is due to a change in the early stages of healing: extract stimulates eosinophils migration to the area of damage, while the number of neutrophils decreases. This can lead to a prolonged inflammatory phase and the associated slowdown in repair.

In certain regions of Siberia and Baikal area, the main causative agent of diphyllobothriasis of human and animals is gull-tipeworm Dibothriochephallus dendriticus. In last decade, there was heightened interest to the study of molecules secreted by helminth which can modulate the immune response of their mammal hosts, particularly human. Bioinformatic analysis of transcriptomes gives opportunity to obtain data on proteins synthetized in certain time point and find among them ones the most significant for immunological functions. The aim of our study was to carry out transcriptome analysis of adult D. dendriticus. Adult D. dendriticus were pulled from the gut of herring gull. Total RNA was extracted with TRIzol reagent. Bar-coding transcriptome libraries were created. Sequencing obtained libraries was carried out using high-performance sequencer Illumina NextSeq550. De-novo assembly of transcriptome was performed. Annotation of obtained transcripts was done with Blast2Go software. Annotation allowed to describe their classification in terms of biological processes, molecular functions, and cellular components. At the next step, we plan to use D. dendriticus, assembled and annotated with transcriptome of plerocercoids, to search genes, potentially coding proteins that have an immunomodulatory effect on their hosts and also for identification of the proteins in secretome of parasites.

No abstract

The tapeworm Ligula interrupta of the genus Ligula (Digramma) (Cestoda: Pseudophyllidea) is a specific parasite of freshwater cyprinid fish; its plerocyrcoids are localized in the body cavity causing heavy parasitic pathology. With parasitosis, an important role in the regulation of the pathological process is assigned to the participants of the organism’s protective reactions, among which a special pool of immunocompetent cells – leukocytes – is distinguished. In the literature, there are single data on hemo- and immunopoiesis goldfish with digrammosis. In our work, new data were obtained on the leukocyte composition of the blood of goldfish Carassius auratus (Linnaeus, 1758), infected with Ligula interrupta in conditions of the native range (Shilen Lake and Cheremukhovoe Lake, Lake Baikal basin). All fish specimens caught with seine nets, both infested and noninfested with L. interrupta, were identical by the size and age composition (age +3…+5, body length 145–237 and 150–180 mm, respectively, weight 100–184 and 120–174 g). Hematological studies were carried out according to the Sbornik [2]. To quantify the individual types of leukocytes, the leukocyte profile, expressed in absolute terms, was calculated. Three groups of cells were revealed in the blood of all goldfish species: blast forms, granulocytes (neutrophils, pseudobasophils) and agranulocytes (lymphocytes, monocytes). The decrease in the blood of infected fish of the total number of leukocytes and their various types at all stages of development, the violation of the proliferation and differentiation of lymphoid and granulocytic elements in the studied organs, the formation of vacuolated and atypical cells, the absence of circulating basophils and eosinophils were established. It has been shown that in this parasitic system, partner relations are reduced to the launch of L. interrupta mechanisms that regulate the host's protective immunological processes by the type of inhibition of the acute inflammatory response and the development of mild chronic inflammation.

Parasites regulate host immune response via secretion of soluble mediators which interact in a certain way with cells and molecules of the immune system. The aim of the study was to determine changes of prostaglandins E2 и D2 content in Dibothriochephallus dendriticus plerocercoids and also in the incubation media during incubation of tapeworms with addition of blood serum from the intermediate host – Baikal cisco. D. dendriticus plerocercoids were retrieved from the host body cavity, ashed in the physiological solution and placed in incubation media. Microcolumn high-performance liquid chromatography was used to detect prostaglandins. Concentration of prostaglandins in the plerocercoid organism increased insignificantly after incubation in the Hanks’ solution with addition of blood serum, when compared with incubation in the Hanks’ solution only. Concentration of prostaglandin E2 increased significantly in the incubation media after incubation of plerocercoids in the Hanks’ solution with addition of blood serum. Prostaglandin D2 was also identified in high concentrations after 12 h and 24 h of incubation, whereas prostaglandin D2 was not quite detected during incubation in Hanks’ solution only.