Zhurnal obshchei biologii最新文献

Betula pendula and B. pubescens are widespread species inhabiting the forest zone of Russia. At the same time, they are closely related species making up transitional forms. It is believed that their ecological ranges are overlapping to a great extent, although B. pubescens is more hydrophilic than B. pendula and less exigent to sunlight. These data, obtained by means of empirical observations, help to understand the ecology of both birch species but so far are not statistically proved. An analysis of habitat distribution of the two birch species is carried out, and a comparison is performed of their ecological relations with such factors as humidification, trophic status, acidity, illumination, and nitrogen soil richness (graded by D. Tzyganov scales). It is shown that B. pendula and B. pubescens differ significantly with relation to humidification, soil richness, nitrogen concentration, and illumination, while do not differ with relation to acidity. Habitat preferences indicate that B. pubescens is more eurytopic species than B. pendula. Although synecolog-ical ranges of both species overlap, their synecological optima still clearly stand apart.

e-mail: mu4@eco.nsc.ru Four aspects related to succession theory are highly disputed. The first aspect concerns broad usage of the term "succession" for any level of life organization. The second aspect concerns the compatibility of chronological and chorological community successions. The third aspect deals with the semantics of the "succession" notion. And the fourth aspect relates to the compatibility of the concepts "succession" and "ecosystem evolution". Indiscriminant use of the term "succession" has been eroding its original meaning. Succession pertains only to the coenotic level of life organization, rather than any level. Succession is not a mere substitution of living forms at different ontogenetic stages, nor merely a change in population structure or biological species composition: succession is an optimization process of a coenotic relations system. Biotic changes at other levels take place independently of coenotic processes. Succession gives an impression of a stochastic chorological sequence only when considered within the frameworks of one subjectively or arbitrary chosen habitat. The latter is regarded as a reference one, while ignoring other neighbouring habitats where biota also undergoes complementary successional changes in different degrees. Recently an importunate postulate urging to believe succession to embrace only chronological community sequences, occurring in one and the same habitat during long time, is being increasingly discussed. This claim is not justified as any succession inevitably embraces several habitats, either successively or simultaneously. The stock of biota in one habitat is evidently not enough for the constant stochastic process. All habitats undergoing successional changes, rather than being isolated and functionally self-sufficient, are arranged in catenas, i.e. standardized chorological sequences determined by geomorphology, drainage, hydrology, microclimatic trends and biotic interchange within the corresponding biome. Therefore succession represents not just a chronological, but rather chrono-chorological phenomenon. Such notion perfectly complies with the gnoseological principle of indivisibility of time and space, which can transform accordingly from one into another. The term "succession", both literally and semantically, denotes inheritance and stereotyping of the environmental experience in an ecosystem, conventional and optimal for the given biome, rather than ecosystem transition into a critically different state. Deviation from a stereotype is possible only in the eluvial ecosystems of catenas, where matter turnover is highly imbalanced, thus providing biota a chance to implement its evolutionary potential. The other ecosystems of a catena exclude this possibility due to predetermination of their ecological regimes. In those ecosystems successions are often interrupted and then resumed at different starting points, thus ensuring persistent mitigation to ecosystem evolution, whic

In every one case out often, the reason behind female infertility turns out to be an orphan disease called 'hypogonadotropic hypogonadism', the single symptom of which is the reduced level of gonadotropins and, as a consequence, amenorrhea in females. Most often, hypogonadotropic hypogonadism is caused by disorder in secretion of gonadoliberin, the product of gene GNRH1. However, the disease is heterogeneous one, so it may origin from either genetic or non-genetic causes. To study the genetic component of the disease pathogenesis, we conducted molecular-genetic analysis of 11 gene-candidates controlling synthesis and secretion of gonadoliberin as well as several gene-candidates functioning as neurodevelopmental and neuroendocrine regulators. In the study participated a group of patients afflicted by hypogonadotropic hypogonadism of an isolated form (n = 10), and a control group of healthy women (n = 20). All women were of reproductive age, with no detected mutations in gene-candidates that could cause any pathological effect. The data on gene-candidates expression in white blood cells are indicative of an increased expression of gene GNRH1 in the sampled patients as compared to the control group (p < 0.05). Other genes demonstrate heterogeneous expression both in the patients group and the control group. Thus, increased expression of gene GNRH1 in blood cells appears to be associated with the isolated form of hypogonadotropic hypogonadism and, in prospect, may be used as one of the disease markers.

Just like the studies of species adaptations phenomenology do not reveal the mechanism of a new species adaptation emerging (speciation), so the enormous bulk of data on phenomenology of ecosystem processes, collected to date, does not disclose the mechanism of evolution at the ecosystem level of living matter organization. An attempt is made to mark out, among the whole variety of evolutionary events in ecosystem form of life, those components attributable to rnicroevolution (by analogy with successful studies of 1940s applied to population-species form of life). It is assumed that at the ecosystem level biogeocenosis (BGC) should be designated as an elementary evolutionary structure, alteration of a BGC species composition — as an elementary evolutionary event, gene pool of a species population (cenogenome) — as elementary evolutionary material, and natural group (cenogenetic) selection — as a directed elementary evolutionary factor. An origin of a new or destruction of an old BGC turns out to be a qualitative stage of microevolutionary process at the ecosystem level.

In the review, the problem of plant movements (photo- and gravitropism) is discussed. The contemporary data on physiological and molecular mechanisms of tropisms in underground shoots and roots are presented. Special attention is paid to diagravitropism phenomenon in underground shoots (stolons and rhizomes) that grow in perpendicular direction to the Earth's gravitational axis. The role of phytochrome control in maintaining the horizontal growth of stolons and rhizomes is demonstrated, and physiological mechanisms of photo- and diagravitropism are discussed. It is shown that switching of an underground shoot tip from diatropic to ortotropic (vertical) growth is dependent on the carbohydrate and phytohor-mone balance. The perspectives are outlined for further exploratory studies on mechanisms of growth orientation and morphogenesis of underground diagravitropic shoots.

We studied the relationship between female mate choice and male-male competition in Campbell's dwarf hamster. Sexually motivated (SM) females chose between two tethered male siblings that differed in expression of sexual traits. Males were unrelated to the female and able to contact and copulate with her. The same males were used in encounter experiment with the following free access of competing male to another SM female. We measured males' sex-related morphology of body mass, mid-ventral specific skin gland, ano-genital distance, and external testicular diameter. We also estimated levels of blood testosterone and cortisol, specific T- and B-cell immune responses to antigens, as well as aggressive and sexual dominance. We found out that female mate choice was not dependent on male aggressive and sexual dominance estimated through encounter experiments. Both in female mate choice and male-male competition experiments (encounter of males and free excess of males to receptive female) successful males did not differ from unsuccessful males in expression of sexual traits (ST). Among males with higher expression of ST mate choice by the female was not associated with aggressive dominance and sexual dominance of a male. There were no significant differences between successful and unsuccessful males in variables treated as potential predictors of male's success, both in female mate choice and male-male competition experiments. Variables explaining female's preference and male's aggressive dominance, which were revealed by General Regression Model analysis, did not coincide. Our results suggest that there are no reasons to discuss the expression of ST in Campbell dwarf hamster males in terms of intersexual or intrasexual selection mechanisms or in terms of their interaction. At the same time, our study demonstrates that testing theoretical models such as "Handicap hypothesis" or "Immunity handicap hypothesis" may face difficulties, which are discussed in the text.

The emergence of plants with red leaves is related to accumulation of permanent anthocyanin pigments. Their temporary production under unfavorable environmental conditions is usually treated as an adaptive trait facilitating thermal stability and resistance to pests and diseases. The main pigment that is produced temporarily in almost all plant species is cyanidin monoglycoside. Using common barberry and its purple-leaf variant as a case study we found out that the predominant pigment in red leaves turns out to be the methylated derivative of cyanidin, namely peonidin-monoglycoside, although that does not alter the qualitative composition of anthocyanin pigments in red and green leaves. Ample accumulation of peonidin in the plants is shown to be inert with regard to basic functional properties: the plants continued to grow and bear fruits, though in different proportions. It is pointed out that more intense illumination leads to changes in energetic state of photosynthetic apparatus which are most prominent in the purple-leaf variant. Judging by the changes in fast fluorescence at different levels of illumination, red leaves at a low level of illumination utilize solar energy less efficiently by comparison with green ones.

Clado- and semogenetic approaches, when used in concert, make it possible to resolve questions concerning phylogenetic relationships between a group representatives as well as phylogenesis of those representatives' traits. Parental care patterns and other forms of reproductive behavior, along with a reproductive strategy as a whole, can be subjects for semogenetic analysis to no lesser extent than morphological structures sensu stricto. One of the highly specialized forms of parental care in fishes, including suborder of labyrinth fishes and their sisterly groups, appears to be parental food provisioning. In my view, evolutionary origin of post-embryonic brood provisioning in bony fishes is related with three distinctive features, namely: 1) In fishes, different forms of post-embryonic food provisioning are convergent in their origin. 2) Any kind of brood provisioning is realized through exploiting the trait already existent and maintained by selection due to offspring fitness enhancement. 3) The main evolutionary path of this phenomenon emergence and development consists in the function expansion and replacement. This hypothesis does have the heuristic power, since it allows predicting the presence of the reproductive strategy component in question through identification of adequate basic adaptations. Despite the fact that parental care occurs in a majority of anabantoid fishes, there still are several species for which such care is not known. On cladogram, these species by no means take the basal position but are surrounded by fishes providing care for their eggs or even hatchlings. The parsimony principle leads to the suggestion that parental care is a plesiomorphic trait in the suborder Anabantoidei (or in the order Anabantiformes). It seems that the ancestors of present day non-caring species that take various positions within this phylogenetic group were fishes showing parental care. Later on, their reproductive strategy has changed as a result of r-selection. If this hypothesis is correct, the absence of parental care should be considered as a case of reproductive strategy degradation. It is quite probable that parental food provisioning was a component of the ancestral reproductive strategies. It is also possible that reproductive strategy of the present day Anabantiformes supposedly not caring for their offspring, actually includes some optional forms of parental care.

Using long-term direct observations in a Polytrichum-Myrtillus pine forest, we have constructed and verified a homogeneous Markov chain model for two dominant species (Vaccinium myrtillus and V. vitis-idaed) at the late stages of succession. The sampling design features a large sample size (2000 quadrats) on permanent transects, several re-examinations with the interval of 5 years, and the use of species rooted frequency. As a model of the process under concern, the discrete Markov chain accounts for the following four states: both species being absent on the quadrat, one of them being present alone, and the joint presence of the both; the model time step coincides with the time interval between observations. The model is calibrated on the data of two successive examinations and verified on that of one more examination. All possible transitions between the states are revealed to realize in quadrats for one time interval, as well as the absence of transitions at each state, which results in the complete digraph (directed graph) of transitions. Major model results are obtained by the formulae of finite Markov chain theory: the steady-state square distribution, cyclicity characteristics, and the mean durations of stages in the fine-scale dynamics. As a steady-state (stable) outcome of succession, the distribution among quadrats is expected where 30% of quadrats are occupied by V. myrtillus alone, 11% by V. vitis-idaea alone, both species are present on 18% of quadrats, and 41% of quadrats are 'empty'. This demonstrates a possibility for V. myrtillus and V. vitis-idaea to coexist stably at the latest stages of succession, with the clear predominance of V. myrtillus, yet without competitive exclusion. The quantitative characteristics of cyclicity and the durations of stages in the fine-scale dynamics enable us to estimate the total duration of secondary post-fire succession as about 45 years (to reach a distribution of states that differs less than 5% from the steady-state one). Out of the four states specified, the quadrats with V. vitis-idaea alone persist for the least time (8 years) on the average, while 'empty' ones persist for the greatest time (18 years). Forecasting the dynamics for one model time step forward and comparing the forecast with the real square distribution have revealed the measure of difference to be 5.4%. This illustrates the efficiency of the (time-)homogeneous Markov chain as a short-term forecast tool, yet leaves open the question whether the homogeneity hypothesis be true in the longer term.

The sectional model of system dynamics of regular branches of a tree together, with submodels for initial growth inhibition and inter-verticil branches, has been extended to the range (0, 3) of fractal parameter ц that connects green biomass and a spruce size, В ~ H µ . It is shown that spruce branches of first three orders appear in the subrange of µ (0, 1). Branches of the first order appear at µ ≈ 0.25. Inter-verticil branches appear at µ ≈ 1.4, which may be viewed as a means of spruce adaptation to unstable lighting conditions. The presence of green biomass at µ < 1.0 indicates that it can be represented as a set of photosynthesizing points (hypothetical cyanobacteria) placed in space. Therefore, the fractal properties of the set of points on the line segment have been considered as a model. It is shown that the condition µ < 1.0 can be fulfilled only if the points are arranged in groups. At that, µ is practically independent of groups alignment while depends on the number of groups and the number and type of points distribution within groups. Based on these fractal properties of points alignment within groups along the segment, and the hypothesis of trophic nature of organelles symbio-genesis in eukaryotic cells, an idea of a two-stage mechanism of proto-plants emergence was formulated. The mechanism is manifested through the motion along the trajectory of endosymbiosis, beginning with a fixed number of points in the group and then with an increase in the number of groups, until, in course of evolution, the host of endosymbiosis would create an infrastructure for the supply and inter-group interaction of cyanobacteria. At this stage, µ decreases from 1 to ≈ 0.25. When the infrastructure is created and it becomes possible to increase the number of points in the group, the motion along the trajectory occurs through doubling the number of cyanobacteria in a group. At this stage, µ value increases to 1. At the first stage, motion along such a composite trajectory results in slow growth of the photosynthetic system size, even with an exponential increase in the number of cyanobacteria groups. The size grows rapidly at the second stage, after the limitations on growth of cyanobacteria number within groups are taken off. It should be noted that such an initial growth inhibition occurs also in modern trees, and is reflected in the initial slow increase in the number of the orders of tree's branches.