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New "mechanisms" for biodiversity data exchange

In the modern world, the success and representativeness of the study of biological diversity largely depends on the availability of newly emerging information and the timely and easy exchange of new data.

This problem is relevant for scientists – classifiers and taxonomists and represents the main idea of ​​an international conference "Information technologies in the study of biodiversity."

This year the conference was held in Ekateringburg from 05 to 10 October. The meeting was attended by M.G. Khoreva, Candidate of Biological Sciences, Leading Researcher of the Laboratory of Botany, head of UNU Herbarium MAG.

In the new issue of our online journal, you can get acquainted with the details of the past meeting, as well as with modern IT-mechanisms that improve the interaction of scientists and nature lovers in the field of biological diversity.

The monograph "Acanthocephalan Corynosoma strumosum in paratenic hosts: Relationships at the organismic level in nature and experiment" by V.P. Nikishin and E.M. Skorobrekhova have been published.

The monograph "Acanthocephalan Corynosoma strumosum in paratenic hosts: Relationships at the organismic level in nature and experiment" by V.P. Nikishin and E.M. Skorobrekhova have been published.

For the first time, the study results of the relationships between acanthocephalans and paratenic hosts are summarized. Using light and electron microscopy, the organization of the capsule surrounding the acanthocephalan Corynosoma strumosum in natural paratenic hosts - marine fish of nine species (delta smelt, pond smelt, Far Eastern navaga, yellow-finned sole, common greenling, Steller’s  sculpin , Hadropareia middendorffii, Pacific halibut and eastern eelpout), has been studied. By the nature of the cellular response (encapsulation), paratenic hosts are divided into three groups, the extreme variants of which are fibroblastic (smelts, navaga) and leukocytic (Hadropareia middendorffii, sole, sculpin, halibut, eelpout) capsules; in the greenling, the corynosomes are surrounded by intermediate capsules.

For the first time, the fact of the formation of a thick layer of glycocalyx on the surface of acanthocephalans in most paratenic hosts was established, which is similar to that, formed in many acanthocephalans and some cestodes in intermediate hosts. The participation of the glycocalyx in the defense against the host cellular response, in particular, against the action of macrophages, has been shown. For the first time, the phenomenon of a change in the newly formed glycocalyx layer was discovered after several days of infection and the beginning of the formation of a leukocyte capsule; it is assumed that this phenomenon is caused by the glycocalyx overflow with host antibodies.

It has been experimentally established that the formation of a leukocyte capsule consists of two main stages. At the first stage, the acanthocephalan is surrounded by leukocytes and macrophages, at the second, fibroblasts migrate into the capsule and form collagen fibers.

During experimental infection of unnatural hosts (sand lizard Lacerta agilis, common frog Rana temporaria, and grass snake Natrix natrix), corynosomes are surrounded by leukocyte capsules, which, in addition to “normal” leukocytes and macrophages, contain giant multinucleated macrophages; the life span of acanthocephalans in these hosts is several weeks. In the nuclei of macrophages of infected lizards, single strictly spherical bodies were found, formed by a material with electron density significantly exceeding that of heterochromatin and nucleoli; it is assumed that their occurrence is associated with increased activity of macrophages provoked by invasion by corynosomas.

Experimental infection of another unnatural host, the aquarium fish Hemichromis bimaculatus, was accompanied by migration of fibroblasts to the parasite and degenerative changes in its tegument. During thirty days of the experiment, some of the worms died; however, given the predominance of fibroblasts in the capsule, the cause of death probably was not the host's cellular response, in contrast to the cases with lizards, but some other factors.

The results obtained made it possible to formulate hypotheses about two strategies of the relationship between the worms and paratenic hosts and the specificity of these relationships.

Figures 1 and 2 - Fibroblast capsule: 1. General view of the acanthocephalan enclosed in a fibroblast capsule (K). 2. Ultrastructure of fibroblasts (Ф) and collagen fibers (КВ). ЖT - adipose tissue, T – acanthocephalan’s tegument.

Figures 3 and 4 - Leukocyte capsule: 3. General view of the acanthocephalan, enclosed in a leukocyte capsule (K). 4. Ultrastructure of the surface part of tegument (T) of the acanthocephalan and cells of the surrounding capsule (K).  Г - glycocalyx, H - neutrophil, Э - erythrocyte.