Zhurnal obshchei biologii最新文献

Distribution models were constructed for 36 species of small mammals from South-Eastern Transbaikalia. Distribution of environmental factors (climatic data and remote sensing of the earth surface) in the set of localities where each of the species was caught was taken as initial data for modeling. Species distribution ranges can be explained by distribution of environmental factors only in 30 cases out of 36. Seventeen of them can be explained by one or two environmental factors only. In 6 cases notable influence of historical factors or interspecific competition on present species distribution was found out. For these 6 species, modeling results make it possible to suggest hypotheses about reasons behind present distribution, which could not be advanced without modeling approach.

Upward and regeneration fluxes of inorganic nitrogen and phosphorusin the euphotic zone of the Black Sea deep waters were estimated using data from long-term observations of nitrate and phosphate vertical distribution and modeling of plankton month- and area-averaged nutrients excretion. The upward fluxes were calculated using monthly average nitrate and phosphate concentrations and their gradients beneath the euphotic layer assuming that the vertical transport rates are controlled by the density gradient at the upper layer of the main pycnocline throughout the year. According to the calculations, the nutrient input into the euphotic layer due to physical processes changes gradually throughout the year from minimum values in July-August (0.1-0.3 mg-atN x m(-2) x day(-1) and 0.02-0.04 mg-atP x m(-2) x day(-1)) up to maximum ones in February-March (1.2-1.8 mg-atN x m(-2) x day(-1) and 0.2-0.3 mg-atP x m(-2) x day(-1)), contrary to the seasonal dynamics of the regeneration flux rates. In summer, plankton regeneration rates increase nearly five-fold as compared to the winter months. The contribution of the upward flux to the total nutrient euphotic zone input was calculated and designated as F(N)(F(P))-ratio along the lines with the f-ratio and e-ratio that reflect the ratio of "new" production and particle export to primary production, respectively. The monthly means vary for F(N) from 5 to 50% and for F(P) from 10 to 70% throughout the year in the same manner as the upward flux. Relationships between the monthly mean values of F(N,P) and vertically integrated nitrate and phosphate concentrations, chlorophyll "a", phytoplankton biomass, and primary production in the euphotic zone were established. The obtained relationships correspond to the general relationships between primary production, "new" production and the sinking flux of particles known for the Ocean. Potential values of "new", regenerated, and total production of phytoplankton in the deep-water areas of the Black Sea are identified. Average monthly and annual primary production estimates, calculated on the base of nutrient flows, are consistent with estimates of primary production according to the averaged data of in situ measures.

We selected Campbell dwarf hamsters (Phodopus campbelli Thomas, 1905) for low and high humoral immune response to the sheep red blood cells (SRBC) challenge in three generations (P, F1, F2). Non-specific innate immunity and acquired T-cell immunity, resting metabolic rate, testosterone, and cortisole hormone levels, reproductive characteristics, including maturation related morphological traits, and aggressive behavior were studied within sets of males:with low (LI) and high (HI) immune response to SRBC. We found no difference between LI and HI males in cutaneous response to injection of phytohemagglutinin, (DTH test for T-cell immunity), in activity of Peroxidase - Endogenous Hydrogen Peroxide System of Neutrophils , in the white blood count, in resting metabolic rate, in body mass and ano-genital distance at the age of two months, in the blood level of testosterone before and after recurrent immunization by SRBC and in the blood level of cortisole in response to the social stressor (10 min encounter in the neutral arena). At that, LI males had significantly higher basal level of blood cortisole, were less aggressive in response to stranger male and had smaller testosterone-dependent mid-ventral specific skin gland at the age of two months. Males of two groups did not differ in the initial mating success with intact young females (time since pair formation until first litter born), although females of LI males born fewer number of pups. In fact, our results do not support the Handicap Immunocompetence Hypothesis (Folstad, Karter, 1999) which is based on the assumption of trade-off between immunocompetence and reproductive effort.

Genetic integration of diverse organisms results in generation of three types of the super-species systems of heredity: metagenome (set of genetic factors of the microbial community which occupies a certain ecological niche), symbiogenome (functionally integrated system of the partners' symbiotic genes) and hologenome (entire hereditary system of a symbiotically originated organism). The integrity of metagenome is based on the cross-regulation and horizontal transfer of genes in co-evolving organisms which in the soil microbial communities are accompanied by maintenance of the stable extracellular DNA pool. Formation of symbiogenome is related to the highly specific partners' signaling interactions which are responsible for development of the joint metabolic pathways based on the specialized cellular and tissue structures. Transitions of symbiogenome into hologenome are due to the endosymbiotic gene transfer from microsymbionts to their hosts. In symbiotic bacteria, these transitions are coupled with establishments of multi-component, reduced and rudimentary genomes revealed for the ecologically obligatory symbionts, genetically obligatory symbionts, and cellular organelles, respectively. Their evolution is related to the stringency of transmission of microsymbionts by hosts increased from pseudo-vertical (via environment) to the trans-embryonic (via embryos and the surrounding tissues) and trans-ovarian transmission (via germ cells) which are culminated in the cytoplasmic inheritance of cellular organelles. We suggest the hypothesis about generation of endophytic plant symbiogenome on the basis of soil metagenome subjected to the control of host by its involvement into the quorum sensing auto-regulation of microbial community.

We studied seasonal population dynamics in birds using four thrush species from the Yenisei middle taiga region as an example. Long-term data on bird route censuses, capture-mark-recapture, and nest observa- tions were incorporated in the analysis. Particularly, methodological problems that complicate a direct comparison between assessed numbers at different phases of the annual cycle are considered. The integrated analysis of the results allowed comparing changes in numbers, energy expenditure, age structure, migrating status, and density distribution of selected populations during the snowless period and relating them to seasonal changes in food resource abundance. Thrush population numbers within the breeding range, and their energy consumption in the Yenisei middle taiga proportionately reflect the seasonal change in abundance of food resources. The compliance between resource intake and carrying capacity of the environment is attained by: timing of arrival and departure regarding to the species' range of tolerance; change in numbers as a result of reproduction and mortality; change in numbers due to habitat changes and long-distance movements; increasing energetic expenditures during reproduction and molt; timing, intensity and replication of nesting attempts; timing of molt and proportion of molting individuals in a population; individual variations of the annual cycle. Reproductive growth of local bird populations is not fast enough to catch up with seasonal growth of ecosystems productivity. Superabundance of invertebrates at the peak of the season offers a temporal niche which, on the one hand, is suitable for species capable of diet switching, while, on the other hand, may be used by specialized consumers, namely tropical migrants for whom, at high resource level, a shortened breeding period suffices.

Sod transplantation experiment was carried out for 24 years in alpine communities, Teberda Reserve, the North-West Caucasus, Russia. Age of maturity (AOM) was estimated as a period between first registra- tion of a species on.a permanent plot and flowering shoot appearance. Mean species AOM varied from 2.3 years (Antennaria dioica with clonal propagation) to 13.7 years for Taraxacum stevenii (non-clonal plant). General gradient of alpine plant traits and population strategies was determined. It represents a continuum ranging from ruderal--stress-tolerants (shorter AOM, clonality, shorter leaf life span, low rate of mycorrhizal infection, low regrowth ability, low generative shoot number, low specific leaf area and leaf nitrogen content) to competitor--stress-tolerants (longer AOM, longer leaf life span, higher rate of mycorrhizal infection, higher regrowth ability, high generative shoot number, high specific leaf area and leaf nitrogen content).

Major histocompatibility complex (MHC) appears to be a suitable tool for solving various tasks of popu- lationgenetics. Information on genetic basis of immunity facilitates understanding of evolutionary his- tory and assessment of current state and prospects of studied population/species survival. On the one hand, MHC variability is maintained through pathogen dependent mechanisms, i.e., directional selection of individuals resistant to diseases, that are present in the environment and balancing selection which gives advantage to those individuals carrying unusual or rare alleles of MHC genes. On the other hand, MHC genes have an influence on reproduction efficiency of individuals. Because of MHC polygeny, its studying requires an application of methods that introduce additional stages between amplification of a certain gene segment and its sequencing. In the article, different tech- niques of allele separation are considered, as well as a simplified version of MHC variability analysis based on the examination of microsatellite loci. Despite the high information value of MHC, it is still not used in zoological studies as often as it deserves. Using as an example predatory mammals of Felidae family which contains quite a few threatened species, we show that a majority of studies on MHC in wild cats is descriptive ones and only few of them deal with genes comparative analysis. The rise of interest to the studies of major histocompatibility complex in non-model species may help not only in solving the fundamental problems of evolution and phylogenetic structure of the family but also in planning the measures for conservation of rare and endangered species exposed to various anthropogenic stresses.

In subterranean rodents, which dig down the passages with frontal teeth, adaptation to the underground mode of life presumes forming of mechanisms that provide protection against inhaling dust particles of different size when digging. One of such mechanisms can be specific pattern of air flow organization in the nasal cavity. To test this assumption, comparative study of geometry and aerodynamics of nasal passages has been conducted with regard to typical representative of subterranean rodents, the mole vole, and a representative of ground rodents, the house mouse. Numerical modeling of air flows and deposition of micro- and nanoparticle aerosols indicates that sedimentation of model particles over the whole surface of nasal cavity is higher in mole vole than in house mouse. On the contrary, particles deposition on the surface of olfactory epithelium turns out to be substantially less in the burrowing rodent as compared to the ground one. Adaptive significance of the latter observation has been substantiated by experimental study on the uptake ofnanoparticles of hydrated manganese oxide MnO x (H2O)x and Mn ions from nasal cavity into brain. It has been shown with use of magnetic resonance tomography method that there is no difference between studied species with respect to intake of particles or ions by olfactory bulb when they are introduced intranasally. Meanwhile, when inhaling nanoparticle aerosol of MnCl2, deposition of Mn in mouse's olfactory bulbs surpasses markedly that in vole's bulbs. Thereby, the morphology of nasal passages as a factor determining the aerodynamics of upper respiratory tract ensures for burrowing rodents more efficient protection of both lungs and brain against inhaled aerosols than for ground ones.