Vol 46, No 2 (2019)

The effect of a thermostable toxin of Yersinia pseudotuberculosis (in comparison with that of dexamethasone) on the functional activities of two types of phagocytes (P1 and P2) was studied in the holothurian Eupentacta fraudatrix. A high level of NO was shown to be a marker of intact P1 cells, while the high activity of arginase was a marker of P2 cells. The antioxidant defense in the P1 type was more pronounced than that of the P2 type. At the same time, the toxin inhibited the functional activity (generation of reactive oxygen species) of P1 phagocytes after 1 h of incubation and induced primarily the activity of P2 phagocytes, compared to that of P1 cells, after 24 h. In contrast to dexamethasone, which induced the transformation of the P1 phenotype into the P2 phenotype, the toxin promoted the mutual acquisition of the phenotype features by these two types of phagocytes. An analogy between the P1 and P2 phagocytes of the holothurian and M1 and M2 macrophages is discussed.

Experimental data published earlier confirming the representations of the reticular theory of the organization of the nervous system are analyzed. It is noted that Sherrington’s evidence has refuted the main concept of the neuronal theory of Ramon y Cajal, the law of dynamic polarization of neurons. After the detection of gap junctions (GJs), the adhesion of neurites, their high electrical and metabolic permeability, and their cumulative interaction were detected. Data demonstrating that GJs are able to transform into syncytial perforations are given, and somatic GJs, under favorable conditions, can convert neurons into dikaryons. It is assumed that all the phenomena described are consecutive stages of a single process of reconstruction of the outer cell membrane of the neuron.

The available information on differentiation of the Kamchatka Parasalmo (Oncorhynchus) mykiss rainbow trout populations by microsatellite DNA loci were clarified. Using both traditional estimations of genetic differentiation (common and pairwise F_ST-statistics) and Bayesian clustering methods, the population genetic relationships of the species were determined in the Kamchatka region. It was confirmed that the isolation of Kamchatka rainbow trout populations is confined to large river basins in Western and Eastern Kamchatka. It was noted that the rainbow trout from the Zhupanova River (Eastern Kamchatka), as well as the samples from the Kvachina and Utkholok rivers (Western Kamchatka), are the most isolated by microsatellite loci.

The ability to produce extracellular laccase by strains of Azospirillum (A. brasilense Sp7, Sp107, Sp245, SR80, A. lipoferum SR42, Sp59b, A. picis TAR-3, A. tiophilum Bv-S, and A. amazonense Am) and Niveispirillum (N. irakense KBC1 and N. irakense KA3) has been established. Induction of enzyme activity by a number of aromatic compounds and copper ions has been shown. A homogeneous preparation of the extracellular laccase of A. brasilense Sp245 strain has been isolated and partially characterized for the first time.

The morphology of the body wall is described for five trematode species belonging to four families of the order Paramphistomatida. In all the species under study, the thickness of the outer plate of the tegument is minimal in the sucker cavities and is constant in other areas of the integument, the number and sequence of the muscle layers (circular, longitudinal, and diagonal) coincide. The layers consist either of individual muscle fibers or of muscle bundles. The longitudinal parenchimal muscles, topographically close to the integument, can be mistakenly assigned as the peripheral musculature. The thickness and sparseness of the circular and longitudinal layers vary considerably in different parts of the integument. Diagonal muscles are characterized by an oblique angle of intersection, high regularity of location, and slight changes in thickness.

The effect of cholecystokinin (CCK) on the activity of peptidases (AP) and glycosidases (AG) of the intestinal mucosа in juvenile carp Cyprinus carpio has been studied. It is established that the dynamics of the activity of enzymes of different chains under the influence of hormones varies. Under the influence of exogenous CCK, AP decreases after 0.25, 0.5, 120, 144, and 168 h and AG decreases after 0.5, 48, and 96 hours compared to intact fish. A decrease in AP under the influence of CCK compared with the control is observed in 0.5 and 120 h, while that of AG occurs in 0.5, 48, 96, 120, and 144 hours after administration. The mechanisms of the effect of CCK on the activity of peptidases and glycosidases of the intestinal mucosa in fish are discussed.

This paper presents the results of research into the role of various types of microsites (flat under- and intercrown areas, stumps, fallen logs, mounds, and pits) in the natural regeneration of trees in uneven-aged dark coniferous boreal tall-herb spruce–fir forests of the northern Urals. Areas of microsites of various types have been identified; a general description of natural tree regeneration is provided; the association of undergrowth of various tree species with different microsites was determined; and the undergrowth distribution by ontogenetic states has been assessed. The lowest undergrowth density was registered on flat sites occupying the major part of the community area, while the highest density was detected on elevated microsites (fallen logs, stumps, and mounds) the total area of which is pretty small. The highest density of the undergrowth of all species was observed on stumps. On mounds and fallen logs, it was 4.3 and 3.0 times lower, respectively. It is shown that elevated microsites (stumps, fallen logs, and mounds) are required for successful survival of the undergrowth of various tree species in boreal tall-herb forests.