[Age-related dynamics of roach infection rate with Ligula intestinalis (Cestoda: Ligulidae) plerocercoids and probability of its usage for the calculation of host death rate].

Results of special parasitological dissections of roach samples from catches with the same fishing gear and at the same station (Monakhovo Cove, Chivyrkui Bay of the Lake Baikal) and at the same time in different years (1998-2002) are given. Stability of age-related dynamics of roach infection rate with Ligula intestinalisis in different years with the maximum of prevalence and mean abundance in fish of 3+ age, and the following sharp decrease in these rates in elder age groups, was revealed. Basing on prevalence decreasing of a single roach generation, the rate of fish mortality during its growth from age group 3+ to 4+ was estimated as 15.9-20.7%.

[Morpho-functional changes of cloacal bursa of the herring gull in experimental infection with gull tapeworm].

Using the methods of light microscopy, the quantitative changes in the cells of the cloacal bursa of herring gull (Larus argentatus mongolicus) chicks were studied during experimental infection with gull-tapeworm Diphyllobothrium dendriticum. The area of the follicles within the bursa and the number of eosinophils in the infected chicks were found to increase. In the follicles the number of blast cells and large lymphocytes was elevated. The reduction of small lymphocytes and plasma cells numbers in the infected gulls may be due to a slower cell cycle or cell migration into the inflammatory focus. Overall, the changes in the bursa indicate the suppression of the B-link of the host immune system in tapeworm invasion.

[Changes in mast cell composition in the hamster duodenum in experimental diphyllobothriosis].

The morphometric investigation was performed to study the reaction of mast cells (MC) in mucosal lamina propria of hamster duodenum to experimental infection with tapeworm Diphyllobothrium dendriticum. The invasion was found to result in a significant increase of MC cells absolute content, changes in the proportions of their functional groups, increased anaphylactic MC degranulation, enhanced MC precursor migration and their accelerated differentiation.

[Morphofunctional characteristics of thymus and immunological parameters in golden hamster under experimental invasion with the cestode Diphyllobothrium dendriticum].

Morphofunctional changes induced by the tapeworm in the thymus and blood of its definitive host, by an example of the experimental model "Diphyllobothrium dendriticum--Mesocricetus auratus", have been investigated. The morphofunctional changes in the thymus and immunological transformations in the organism of infested hamster are evidences of rather high immunogenic effect of the D. dendriticum antigens on the definitive host at the period of active growth of the parasites.

[The reaction of the bursa and thymus eosinophils in the herring gull after the experimental infection with gull-tapeworm].

Using the methods of light microscopy, eosinophil topography, quantitative and qualitative changes (degranulation level of and a cationic protein content) were studied in the thymus and bursa of 36 herring gull nestlings Larus argentatus mongolicus (Suskin, 1925) 2 weeks after experimental infestation with gull-tapeworm Diphyllobothrium dendriticum (Nitsch, 1824). Eosinophils in the thymus were located in trabecules, mainly close to the blood vessels, thymic (Hassall's) corpuscles and also directly inside them, while in the bursa they were found within the internodular space. As compared with the control bird counts, relative eosinophil count in the birds with an average invasion intensity was increased 3.8 times in the thymus and 2.5 times in the bursa. In birds with high invasion intensity, these counts were increased 4 times in the thymus and 1.2 times in the bursa.

[New species of Myxosporidia (Myxosporea: Cnidosporidia) from cottids (Abyssocottidae) and the oilfishes (Comephorus spp.) of Baikal Lake].

Two new species of Myxosporidia, Myxidium baicalensis sp. n., Myxidium donecae sp. n. are described from the gall bladder of fishes from Baikal. Myxidium baicalensis sp. n. parasitising gobies Cyphocottus megalops, Asprocottus platycephalus, and other host species, while Myxidium donecae sp. n. parasitising Baikal oil fishes Comephorus baicalensis and C. dybowski.

[Morpho-functional characteristic of the spleen in Baikal seal (Pusica sibirica Gmel.) pups].

Using the methods of light microscopy, the histological structure of the spleen in Baikal seal (Pusica sibirica Gmel.) pups was studied for the first time. It was found that in Baikal seal the spleen is characterized by highly developed supporting elements (thick capsule and numerous branching trabeculae), which are rich in smooth myocytes. By the age of 2-4 weeks, all the structures of white pulp were formed, however, presence of only a few lymphoid nodules with the absent germinal centers indicates that functionally these structures are still immature. Presence of immature forms of granulocytic, erythroid and megakaryocytic lineage shows that the myelopoiesis in Baikal seal spleen continues in postnatal period.

[New species of myxosporidians (Myxosporea: Cnidosporidia) from the oilfishes (Comephorus spp.) of Baikal lake]. / Novye vidy miksosporidii (Myxosporea: Cnidosporidia) ot golomianok (Comephorus ssp.) ozera Baikal.

Two new species of Myxosporidia, Henneguya bayerii sp. n. and Myxobolus korjakovii sp. n. from the kidney of the Comephorus baicalensis (Pallas, 1776) and C. dybowskii Korotneff, 1905 from the Baikal lake are described.

[The survival of Diphyllobothrium dendriticum pleurocercoids during the processing of fish and sanitary helminthologic evaluation of the product]. / Vyzhivaemost' plerotserkoidov Diphyllobothrium dendriticum pri pererabotke ryby i sanitarno-gel'mintologicheskaia otsenka produktsii.

Diphyllobothrium dendriticum plerocercoids' survival in salt water solutions of various concentrations and at various temperature was assessed. Conditions of salt treatment and freezing of the Baikal salmon assuring total release of fish from D. dendriticum plerocercoids are determined. The authors suggested differentiation in sanitary helminthological assessment of fish invasion rate by D. latum and D. dendriticum plerocercoids.

[Sexual dimorphism in reactions to stress during regular and altered photoperiods]. / Polovoi dimorfizm v stressornoi reaktsii pri obychnom i izmenennom fotoperiode.

Sexual dimorphism of rats in response to physiological stress influences was discovered. The emotional stress in female animals caused a sharp intensification of synthesis and corticosterone secretion, while in males there was an increase only in hormone synthesis and not its secretion. Females are more sensitive even to short-term changes in photoperiod. Stress reaction in females under conditions of three-day light depressed sharply and increased under conditions of three-day darkness. Stress reaction in males did not change under these conditions. The reactivity of adaptation system in females shortens the period of adaptation to the altered illumination regimen, which is manifested in the restoration of typical stress reactions. In males, refractoriness to weak stress influences lengthens the period of adaptation, which is manifested in the suppression of typical stress reaction observed in males.

[Ecological and micromorphological aspects of interrelations in myxosporidian--fish parasitic systems]. / Ekologicheskie i mikromorfologicheskie aspekty vzaimootnoshenii v parazitarnykh sistemakh miksosporidii--ryby.

A comparative analysis of the character of interactions in five parasitic systems myxosporidians--fishes (Myxobolus mülleri-Perca fluviatilis, Myxobolus ellipsoides-Phoxinus percnurus, Henneguya zschokkei-Coregonus autumnalis migratoris, Henneguya cerebralis-Thymalus articus nigrescens, Sphaerospora pectinacea-Perca fluviatilis) is given.

[Cytochemical characteristics of the myxosporidian Henneguya cerebralis (Myxosporidia, Myxobolidae) and pathohistological changes in the Kosogol grayling in myxosporidiasis]. / Tsitokhimicheskaia kharakteristika miksosporidii Henneguya cerebralis (Myxosporidia, Myxobolidae) i patogistologicheskie izmeneniia u kosogol'skogo khariusa pri miksosporidoze.

Content and distribution of RNA, protein, DNA, glycogen and carbohydrate components in spores and vegetative sporeforming stages plasmodium of Henneguya cerebralis were described. Pathohistological changes in head tissus of Thymallus arcticus nigrescens are discussed. The conclusion on the relative youth of parasite system "H. cerebralis--Thymallus arcticus nigrescens" is made.

[Changes in the argyrophil stroma of the liver of fishes infested with the pleurocercoids, Triaenophorus nodulosus and Diphyllobothrium dendriticum (Cestoidea, Pseudophyllidae)]. / Izmeneniia argirofil'noi stromy pecheni nekotorykh ryb pri invazii plevrotserkoidami Triaenophorus nodulosus i Diphyllobothrium dendriticum (Cestoidea, Pseudophyllidea).

The argentaffine stroma of the liver of some fishes (Perca fluviatilis, Exos lucius, Paracottus kessleri, Coregonus autumnalis migratorius, Thymallus arcticus) is described. The nature and depth of pathological changes in the argentaffine stroma of the liver at its infection with pleurocercoids of pseudophyllids depend on the infection intensity, host's specificity and on the biocoenotic relationships of hydrobionts in a waterbody.

[Cytochemical characteristics of the labrocyte-like cells in the capsule of the plerocercoids of Triaenophorus nodulosus (Pallas, 1781) and Diphyllobothrium dendriticum (Nitzsch, 1824) cestodes]. / Tsitokhimicheskaia kharakteristika labrotsitopodobnykh kletok v kapsule plerotserkoidov tsestod Triaenophrus nodelosus (Pallas, 1781), i Diphyllobothrium dendriticum (Nitzsch, 1824).

Out of six fish species examined (Esox lucius, Paracottus kessleri, Perca fluviatilis, Leuciscus leuciscus baicalensis, Coregonus autumnalis migratorius, Thymallus arcticus baicalensis) labrocyte-like cells were detected in Esox lucius, Leuciscus leuciscus baicalensis, Coregonus autumnalis migratotius. The cells contain large metachromatic granules. Histochemical methods revealed in them sulfated and carboxylic acid mucopolysacharides. The amount of labrocyte-like cells in the capsules around plerocercoids of Triaenophrus nodulosis from Esox lucits liver depends on the age of the capsule and that of the plerocercoid. It increases when the connective tissue papsule is forming and decreases again under aging and degeneration of the capsule containing plerocercoid. The amount of labrocyte-like cells in the cestodes capsules of Raillietina increases sharply when they locate in an accidental organ (liver). This demonstrates the acuteness of organ reactivity to a nonspecific helminth.