No 4 (2025)

The effect of Azygia lucii fluke infection on the activity of proteolytic enzymes functioning in the stomach of the host pike and the ability of worms to suppress this activity was studied. The activity of a wide range of proteases was detected in the pike’s stomach. In extracts of marita A. lucii, both pepsin-like activity and activity of alkaline proteases, a significant part of which are metal-dependent proteases, were determined. Even with a low intensity of invasion, trematodes cause an increase in the activity of pepsin-like proteases in the host’s stomach. Worm extract suppresses the activity of commercial pepsin, but neither the incubation medium nor the trematode extract have a statistically significant inhibitory effect on the activity of pepsin-like proteases of the gastric mucosa of pike.

The article presents the results of molecular genetic identification of two individuals of the golden jackal, Canis aureus Linnaeus 1758 (Carnivora, Mammalia), hunted in the Vladimir region of Russia. The initial morphological diagnosis was confirmed both by the maternal (sequenced fragment of the mtDNA cytochrome b gene) and paternal (fragment analysis of amplicons of the ZfY gene localized on the Y chromosome) lineages. Both individuals were identified as golden jackals, the sequences of which correspond to the European-Middle Eastern lineage of C. aureus. The presented data confirm new records of the golden jackal outside the stable part of the historical range of the species – in the north of the front of its dispersal in the Central Non-Black Earth Region. We analyze these facts in the context of the expansion of the golden jackal range to the central and northern parts of the Russian Plain.

Some biochemical parameters (total cholesterol, high- and low-density lipoprotein cholesterol, serum triglycerides, total water-soluble protein concentration in blood serum and liver, intestinal mucosa peptidase activity) of the perch Perca fluviatilis (L.) from three reservoirs of the Vologda and Yaroslavl regions of Russia with different levels of mercury pollution were studied. It was shown that in perches with the highest mercury concentration in muscles (0.60 mg/kg wet weight, Lake Kubenskoye), the level of HDL-C, LDL-C, and total cholesterol was significantly higher compared to those in fish from the Sunoga River and the shipping channel of the settlement of Borok (0.38 and 0.012 mg mercury/kg wet weight, respectively). The lowest amount of water-soluble protein in the liver and the highest in the blood serum, as well as a comparatively low activity of intestinal mucosa peptidases were also found in perches from Lake Kubenskoye, the concentration of mercury in the muscles of which was relatively high.

Weakly, moderately and intensively drained peat soils (Histosols) occupied by pine forests (Pinus sylvetris L.) were studied. According to seasonal observations catalase activity of soil profile was divided into two areas – 0–10 and 10–30 sm, using discriminant, canonical analysis, multidimensional scaling and cluster analysis methods (tree clustering and the K-means method). The surface zone is highly active, not homogeneous in reaction kinetics, in which the horizons 0–5 and 5–10 cm are grouped into three separate clusters depending on the depth of drainage. The lower zone, with relatively stable and reduced catalase activity, combined horizons of 10–20 and 20–30 cm of soils of different drainage levels into one cluster. The interdependent effect of environmental factors – soil temperature, soil bulk moisture, redox potential and pH on catalase activity was 98%. The greatest “weight” is brought by hydrothermal indicators with a dominant contribution of soil bulk moisture.

The nitrogen (N) and phosphorus (P) content was studied in the leaves of 6 cereals and 18 non-legume dicotyledonous grass species, as well as directly in the substrates of non-recultivated areas of two different age fly ash dumps. The total number of microorganisms and nitrogen fixers capable of phosphate solubilization and indole-3-acetic acid (IAA) synthesis was analyzed in the rhizosphere of two pioneer (Alopecurus aequalis, Ranunculus sceleratus) and two late successional (Poa pratensis, R. auricomus) plant species. Higher N and P content and lower N/P ratio were found in the leaves of dicot grasses compared to cereals. The number of nitrogen fixers in the rhizosphere of dicots was higher, which coincided with the higher content of total nitrogen in it. The proportion of nitrogen fixers with an increased ability to phosphate solubilize and IAA produce was significantly higher in the early stages of ash dump overgrowth.

Summary of the analysis of the population ecological characteristics of the the eurasian pygmy shrew in the European part of its range, that include results of ecological structure of the population, molting and population dynamics of the shrew. The ecological structure of the population is characterized by a faster increase in juveniles, which amount reaches more than 72% in September. Every year the age structure of the population changes, which correlates to the intensity of reproduction and the total amound individuals in population. The sex ratio depends on the age of the individuals, the season of the year and the condition of the population. As compared to the numbers of the siberian population, we established a relatively low density of population in the study area (0,3 ind. per 100 trap-nights or 2,2 ind. per 10 ditch-days). The number changes noticeably from year to year, but without any sharp periodicity and is general it is not synchronous with the dominant species – Sorex araneus. Nevertheless, over more than 60 years of studies of population of Sorex minutus, only four unclear rises emerged. These increases in numbers occur under the influence of a rather complex combination of an exogenous factors.

Analysis of the motion of microscopic organisms is important for understanding their behavior, intrinsic state, and response to external conditions. Many free-swimming microorganisms move in three-dimensional space along a helical trajectory. When a three-dimensional trajectory is analyzed from video frames, it is transformed into a flat curve. This leads to loss of some of the motion data and, in particular, to errors in the estimates of the traveled path and true speed. We propose to estimate the length of a three-dimensional spiral path using the maximum length of the projection of the trajectory segment. The analysis showed that for rectilinear spiral trajectories, along which organisms move uniformly, this method in many cases allows us to correctly estimate the traveled path and true speed of movement, and to perform a correct comparison of the speeds of different microorganisms.