Vol 44, No 4 (2017)

The contribution of symbiotic microbiota to the adaptation of Drosophila melanogaster to fodder with an increased content of NaCl has been analyzed. The reproduction efficiency and the development rate of D. melanogaster on the saline fodder medium, on which a homogenate of flies from laboratory salt-adapted lines and from control lines not adapted to the salt were inoculated, were compared. It was established that inoculating with homogenized salt-adapted flies significantly increased the efficiency of use of salty fodders by flies in comparison with the control flies homogenate, which is manifested in the increased number of offspring produced by a pair of parents over a fixed time, and also in faster larval development. It was noted that the results obtained were consistent with the assumption that the adaptation of D. melanogaster to salted fodder is largely due not to genetic changes in the experimental populations but to changes in the concomitant bacterial and yeast microbiota.

The effects of the inhibitor of DNA methylation 5-azacytidine on stem (satellite) cells isolated from fetal and definitive skeletal muscles of rats lead to the expression of marker genes of cardiomyogenesis (Gata4, Nkx2.5, connexin-43, n-cadherin, as well as Cacna 1 c encoding the cardiac subunit of the L-type Ca²⁺-channel). Through comparative analysis of the dynamics of expression of key markers of cardiomyogenesis, it was established that satellite cells isolated from fetal muscles have a more expressive potency to cardiomyocyte differentiation in vitro (expression of specific marker genes) compared to cells from muscles of adult animals. In the process of induced cardiomyocyte differentiation, the expression of MyoD and m-cadherin marker genes of skeletal muscle differentiation was not detected, suggesting that in the experiments presented the program of myogenic differentiation of skeletal muscles is inhibited.

The relationship between animal growth and oxygen consumption was studied by the example of the postlarval period in ontogenesis of the newt Pleurodeles waltl. These parameters increased during the first 1.5 years after metamorphosis and then did not change. Gender differences were found for the body mass, growth rate, and rate of oxygen consumption, which in males were less than in females. The mass-specific rates of oxygen consumption in males and females were the same. The relationship between the body mass and the rate of oxygen consumption in immature and mature newts can be expressed by a common allometric equation.

This paper analyses variability of the nucleotide sequence of the mitochondrial cytochrome oxidase first subunit gene fragments in four tick species of the marginatus group—Dermacentor marginatus, D. silvarum, D. niveus, and D. nuttalli. It is noted that, with the exception of D. niveus, the clustering of mitotypes in the marginatus group does not show a clear correspondence of the species identity of ticks, which had preliminarily been established based on morphological characters.

The genetic variability of the greater long-tailed hamster Tscherskia triton of the peripheral population of the southern Russian Far East is evaluated compared to the central populations of China based on the nucleotide sequences of the control region of mitochondrial DNA. The high genetic diversity of the population of the southern part of Russian Far East is established, which does not confirm a hypothesis on reduction of the diversity in the peripheral populations. The presence of three phylogroups is discovered: one within Russia (“northern”) and two within China (“central” and “southern”). A deletion, absent in other taxonomically distant groups of the Old and New World and acquired by the greater long-tailed hamster over the course of its evolutionary history, is present in certain populations of this species. A preliminary hypothesis, according to which the contemporary structure of this species is determined not only by topographical and climatic events, but by human activity as well, is formulated.

We evaluated the susceptibility of Galleria mellonella larvae immunosuppressed by the venom of Habrobracon hebetor to soil entomopathogenic ascomycetes with the use of bait method. It was found that the sensitivity of the modified method was significantly (by almost 200 times) increased as compared with the standard procedure, which provided the isolation of fungi when their abundance was extremely low. Envenomated larvae were more susceptible to the entomopathogenic but not saprotrophic fungi. We presented results of isolation of the entomopathogenic fungi from soils in different climatic zones (from the forest tundra to the steppe) using an improved procedure.

Earlier it was suggested, based on study of the morphological features, that a new taxon of burmarigold, which had been noted in recent decades in several locations on the territory of Russia and neighboring countries and described as an alien species of Bidens connata, is in fact a hybrid species that arose in Europe. This hypothesis was confirmed by the molecular genetic method. A complex of taxa of the genus Bidens from various parts of the areal and their F1 first generation offspring were studied, and a polymerase chain reaction was performed using ISSR primers. It was established that the taxon investigated represents a complex of hybrids and recurrent hybrids that arose in the European part of Russia independently by hybridization of the alien B. frondosa and the aboriginal B. cernua.

The characteristics and growth rates of mash frogs introduced upon the completion of metamorphosis into the cooling ponds of heating stations have been studied. The age composition of frog populations has been determined. It has been shown that an extra year must be added to the visible adhesion lines in the tissue of long bones. It has been found that the population of mash frogs inhabiting the Verkhnii Tagil Reservoir is characterized by not only a longer life span than in the Reftinskoe Reservoir, but also by a sufficiently high frequency of occurrence in the samples of older age groups.

We studied the effect of the peppermint ambient odor on the performance of routine Russian school language tests by primary-school students in a standard classroom, where a noiseless source of odor provided scenting the air by means of free evaporation of the essential oil at a constant low concentration. It is shown that in the presence of peppermint odor the marks for a word dictation test that is based on the longterm memory are significantly higher than in the absence of the odor, whereas the performance of text copying test (based mainly on attention) is not influenced by the presence of peppermint odor.

The variability of the microbial population structure of the gut of omnivorous wireworms Agriotes obscurus (L) and Selatosomus aeneus (L) was studied. The limits of intra- and interspecific and intersite variation were determined. The stability of the microbial composition of the gut allows us to reveal the list of obligate saprotrophs (with 95% probability) using only five replications. In the case of S. aeneus, the influence of starvation and diet change was studied. Starvation changed the microbial population structure, while the diet did not. The results confirm that omnivorous wireworms have a stable gut microbial population, which suggests an advanced mutualistic relationship between wireworms and their gut bacteria, possibly assisting in digestion and providing for ecological flexibility of wireworms.

Two pyrogenic cycles (two succession series) of ecosystems in the boreal forest belt are characterized. One cycle is associated with the subbelt of subgolets (subalpine) spruce and larch forests, and the other, with the subbelt of taiga spruce and larch forests. The bird population at different stages of succession are compared. Quantitative analysis utilizes measures of inclusion and similarity. The avian faunistic and ecological complexes, as well as forest layer aggregations, are considered. As is shown, the ecosystems at the early stage of succession play a significant role in the spread of the Chinese ornithofaunistic complex against the background of prevalence of the Siberian complex. The species involved in both cycles belong to the forest ecological complex. The bird population in the succession systems at later stages and native ecosystems of two subbelts are more similar to one another as compared with the succession systems of the same subbelts at early stages.

The results of study of regeneration periods in pine forests after natural and anthropogenic disturbanses have been presented. It has been found that the rate of recovery depends on the type of disturbing factor. The differentiated effect of climatic factors (air temperature, amount of precipitation) on the growth rate of forests with different types of disturbances has been investigated.