[A syntaxonomic analysis of the initial stage effect on secondary autogenous succession of broad-leaved forest].

Using successional system of Stachyo sylvaticae-Tilietum cordatae association as a case study, the possibilities are considered of applying syntaxonomy as developed on the basis of floristic classification principles. Characteristics of restorative successions on cut-over lands have been analysed at strong and weak disturbance of soil cover as well as in plantings of coenotically weak species Pinus sylvestris and coenotically strong species Picea obovata. High self-restoring potential of the association studied is emphasised.

[The contribution of L.G. Ramensky theoretical legacy to modern vegetation science (to the 130 anniversary of the scientist's birth)].

L.G. Ramensky (1884-1953) was an outstanding Soviet geobotanist of the first part of XX century. Considered is his theoretical legacy and its contribution to modern vegetation science. L.G. Ramensky formulated the principle of vegetation continuum based on which the modern paradigm of vegetation science has been put into shape. The scientist made a contribution to the development of such important theoretical conceptions as types of plant strategy, coenosis and coenobiosis (coexistence of species), patterns of interannual variability in plant communities, ecological successions. The unique ecological scales were established by L.G. Ramensky that characterize the distribution of 1400 species over the gradients of soil moistening, richness, and salinization as well as moistening variability, pastoral digression, and alluvial intensity. He came out against mechanistic notions by V.N. Sukachev on a biogeocoenosis structure. The scientist did not offer his own method of plant communities classification but his well-reasoned criticism of dominant classification played a great role in adoption of floristical classification principles (Braun-Blanquet approach) by phytocenology in our country.

[The conception of plants community: the history and the modern state of the art].

After discussion of many years about the nature of plants community, within the science dealing with vegetation the consensus is reached on pragmatic basis. Most researchers consider plants community as conditionally uniform contour marked out of the multi-dimensional continuum of any type of vegetation. Plants community is a generic notion, within the framework of which types with different models of organization are established. With any type of plants community organization model, the main factor of species association remains to be the ecotope which plays the role of an abiotic matrix. The main traits of a plants community are species composition, its structure, species interrelations, and functional parameters. The main types of species interrelations within a plants community appear to be competition and non-competitive formation of environment. The important role in organization of plant communities belongs to heterotrophic organisms such as phytophages, nitrogen-fixing procaryotes, mycorrhizal fungi, pathogens, and others.

[Basic trends in the development of the theory of syntaxonomy and plant communities dynamics].

Considered are trends in the development of two basic parts of phytosociology--syntaxonomy (vegetation classification) and vegetation dynamics. At the end of XX century, the consolidation of researches in the field of syntaxonomy has taken place on the base of Braun-Blanquet approach, as well as the development of syntaxonomy due to studies of vegetation in new regions, and adoption of information technologies. In Russia, Braun-Blanquet approach has being implemented only in 1980s, because before that its spread was impeded by political climate in the country. Presently, syntaxonomy of vegetation in Russia includes 80 classes, 169 orders, and 377 alliances, at that considerable part of them are new for the science. In the theory of vegetation dynamics, the paradigm shift has occurred in XX century--from organicism to the concept of continuum. From the beginning of XXI century, the interest in general theory of successions has being receded and, instead, particular patterns of successions of different type have being revealed.

[Syntaxonomic analysis of restorative successions after cutting down light coniferous forests of South Ural Region].

Discussed are the possibilities of using syntaxa from floristic classification for the analysis of secondary restorative successions after forest cutting in South Ural Region. Peculiarities of secondary forest communities classification that may be viewed as subjects of indigenous vegetation syntaxa forming, sub-associations or could be systematized according to 'deductive' classification introduced by K. Kopecky and S. Heiny are considered. An example is presented of an analysis of communities succession system formed after cutting down hemiboreal pine and birch-pine herbaceous forests of Bupleuro-Pinetum association. Within this system the processes of divergence and convergence of succession series take place. Divergence occur as a result of lifting of the influence caused by dominants edificating role and manifestation of differences in soil humidification, also as a consequence of soil enrichment by mineral elements after burning down the felling debris. The reason behind convergence is grading influence of renewed forest stand. Trends in species richness changes during restorative successions may differ depending on ecotope features. In course of a succession, models of tolerance and inhibition become apparent.

[Contribution of syntaxonomy to the study of vegetation dynamics].

Of late decades, numerous studies on vegetation dynamics have been carried out and the spectrum of studied objects extended. However, syntaxonomy, while is capable to reveal patterns in vegetation changes, is virtually not used in analysis of succession. Prospects of syntaxonomy application to the study of vegetation dynamics are demonstrated by the example of succession analyses of pasture digression, vegetation changes under influence of recreation, progressive succession at the place of deserted settlements. The special role played by the analysis of syntaxonomic spectre of serial plant communities is discussed. The analysis makes it possible to estimate the serial status of communities by the ratio in their floral composition of species from cenofloras of classes that represent different serial stages of vegetation.

[The analysis of the factors determining species richness of Southern Ural forest communities].

There was analyzed the influence of warmth, moisture, and soil fertility on species richness and phytosociological spectrum of phytocenoses of three classes of Southern Ural autochthonous forests: Querco-Fagetea (nemoraloher-bosa), Vaccinio-Peceetea (boreal forests), and Brachypodio-Betuletea (hemiboreal forests). Environmental factors were estimated by Landolt's scales. We studied the changes of syntaxa of association rank by means of gradient phy-tosociological analysis. In phytosociological specter, in addition to the cenoflora of the three investigated classes, we estimated the representation of species from steppes (class Festuco-Brometea), xerothermal forest edges (class Tri-folio-Geranietea), and meadows (class Molinio-Arrhenatheretea). For boreal and hemiboreal forests, the dependence of cenoses species richness on environmental factors is parabolic, with its maximum in the middle of the gradient. With respect to nemoral forests, species richness declines with increase of environmental factors values. Maximum species richness is registered when the proportion of species of the own cenosis class in the community is maximal. The contribution of the ecotone effect (inclusion of other classes' species in the community composition) enhances as species richness reduces.

[Contribution of the Brown-Blanquet method to the explanation of species richness of the plant communities].

A possibility of estimation of factors of formation of species richness of the plant communities by H-function as a measures of complexity of the phyto-sociological spectrum of communities is proved. The phyto-sociological spectrum reflects contribution of those various syntaxa to the coenofloras that indicate ecotope character and the successional status of communities. Analysis of a wide set of grassy vegetation of the South Ural region (from synanthropic to natural) revealed a linear positive correlation between H-function values and species richness. Primary factors of formation of species richness of the vegetation investigated are general favorability of the environment, variability of the moistening regime and successional status reflecting processes of vegetation transformation under influence of internal (regenerative succession) and external (cattle pasture) causes.

[Braun-Blanquet method of vegetation classification in Russia].

Under consideration is the history and contemporary state of the vegetation classification based on the ecological-floristic criteria (the Braun-Blanquet approach) in Russia. Analyzed are preconditions of dissemination of this approach in the U.S.S.R. in the 1960s, active development of ecological-floristic classification in the 1980s, and most recent developments in the classification theory. The Braun-Blanquet approach became the principal method of vegetation classification in Russian phytocenology. Due to this, Russian syntaxonomists became associated into international community of the vegetation researchers, which allows them to participate actively in the projects on biodiversity conservation. The journal "Vegetation of Russia" much contributed to these developments. The authors respond to A.M. Ghilyarov's criticisms who considers the Braun-Blanquet approach as a "rudiment of the Natural History" useless for the contemporary ecology.

[Synanthropic plant communities: models of organization and features of classification].

It is proposed to distinguish between three models of organization in synanthropic plant communities formed under the influence of man: R-modle, communities of segetal weeds in fields of annual crops and at initial stages of restoration successions; R --> CRS-model, serial communities of the later stages of restoration successions; CRS --> S-model, serial communities of allogenic successions under the influence of grazing and other external factors. The higher units of the ecological and faunistic classification (classes and orders) well represent the succession status and the soil and climate conditions under which synanthropic communities are formed. At the same time, the continual character of synanthropic vegetation makes recognition of plant associations inexpedient in some cases. It is preferable to use the deductive classification method of K. Kopecky and S. Hejny.

Comparative genomics of the lactic acid bacteria.

Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.

The role of histone acetylation versus DNA damage in drug-induced senescence and apoptosis.

The present study was undertaken to determine the significance of histone acetylation versus DNA damage in drug-induced irreversible growth arrest (senescence) and apoptosis. Cellular treatment with the DNA-damaging drugs doxorubicin and cisplatin or with the histone deacetylase inhibitor trichostatin A, led to the finding that all the three drugs induced senescence at concentrations significantly lower than those required for apoptosis. However, only doxorubicin and cisplatin induced activation of H2AX, a marker for double-strand break formation. Interestingly, this occurred mainly at apoptosis and not senescence-inducing drug concentrations, suggesting that non-DNA-damage pathways may be implicated in induction of senescence by these drugs. In agreement with this, chromatin immunoprecipitation experiments indicated that doxorubicin was able to induce acetylation of histone H3 at the promoter of p21/WAF1 only at senescence-inducing concentrations. Collectively, these findings suggest that alteration of chromatin structure by cytotoxic drugs may represent a key mediator of senescence.

Suppressive effect of elongation factor 2 on apoptosis induced by HIV-1 viral protein R.

Rapid CD4+ lymphocyte depletion due to cell death caused by HIV infection is one of the hallmarks of acquired immunodeficiency syndrome. HIV-1 viral protein R (Vpr) induces apoptosis and is believed to contribute to CD4+ lymphocyte depletion. Thus, identification of cellular factors that potentially counteract this detrimental viral effect will not only help us to understand the molecular action of Vpr but also to design future antiviral therapies. In this report, we describe identification of elongation factor 2 (EF2) as such a cellular factor. Specifically, EF2 protein level is responsive to vpr gene expression; it is able to suppress Vpr-induced apoptosis when it is overproduced beyond its physiological level. EF2 was initially identified through a genome-wide multicopy suppressor search for Vpr-induced apoptosis in a fission yeast model system. Overproduction of fission yeast Ef2 completely abolishes Vpr-induced cell killing in fission yeast. Similarly, overexpression of the human homologue of yeast Ef2 in a neuroblastoma SKN-SH cell line and two CD4+ H9 and CEM-SS T-cell lines also blocked Vpr-induced apoptosis. The anti-apoptotic property of EF2 is demonstrated by its ability to suppress caspase 9 and caspase 3-mediated apoptosis induced by Vpr. In addition, it also reduces cytochrome c release induced by Vpr, staurosporine and TNFalpha. The fact that overproduction of EF2 blocks Vpr-induced cell death both in fission yeast and human cells, suggested that EF2 posses a highly conserved anti-apoptotic activity. Moreover, the responsive elevation of EF2 to Vpr suggests a possible host innate antiviral response.

[The problem of continuum versus discreteness in current ecology].

The problem of continuality versus discreteness of vegetation cover ("biocoenotic cover"--more generally) was the object of heated debates for at least hundred years. The ideas of continuality have been spread in the USSR in the 1970-80s but later the adherents of other approach, that focused on the discreteness of vegetation became more active. The author discussed the views of one of them, A.I. Kafanov (2005), published recently in "Zhurnal Obshchei Biologii". It is claimed that pluralistic approach that is characteristic for present ecology makes unnecessary the search for universal law of relationship between continuum and discreteness of biocoenotic cover. This relationship depends on the particular character of biocoenotic cover and the scale of study.

[The meaning of vegetation classification for modern ecology]. / Znachenie klassifikatsii rastitel'nosti dlia sovremennoi ékologii.

Eco-floristic classification (Brawn-Blanquet system) is useful since in similar manner it can establish ecological units of different level (syntaxons) that have high indicative value. Syntaxons can be used as markers of terrestrial ecosystems of different range. Although this system was proposed by analogy with plant taxonomy it reflects vegetation continuum. The application of this approach is based on certain standards and supported by developed software. The elements of arbitrariness in Brawn-Blanquet method are constrained by rules of strict recommendations. The method is considered as necessary in studies of biodiversity in protected areas.

[Does Darwinism really contribute to ecology]. / Ocheviden li vklad darvinizma v ékologiiu?

The author questions Ghilarov's (2003) claim that Darwinism has high explanatory power in ecology. He is agree with S.V. Meyen who believed that beside synthetic theory of evolution (the popular variant on Darwinism) other explanations of evolution are possible. It is emphasized that several processes (e.g., diversification and unification of species at one trophic level, as well as individual and diffusive coadaptations of species of different levels) can contribute to community evolution. Communities cannot be considered as units of natural selection.

Inhibition of human neuroblastoma cell proliferation and EGF receptor phosphorylation by gangliosides GM1, GM3, GD1A and GT1B.

The inhibitory action of gangliosides GT1B, GD1A, GM3 and GM1 on cell proliferation and epidermal growth factor receptor (EGFR) phosphorylation was determined in the N-myc amplified human neuroblastoma cell line NBL-W. The IC50 of each ganglioside was estimated from concentration-response regressions generated by incubating NBL-W cells with incremental concentrations (5-1000 microm) of GT1B, GD1A, GM3 or GM1 for 4 days. Cell proliferation was quantitatively determined by a colourimetric assay using tetrazolium dye and spectrophotometric analysis, and EGFR phosphorylation by densitometry of Western blots. All gangliosides assayed, with the exception of GM1, inhibited NBL-W cell proliferation in a concentration-dependent manner. The IC50s for gangliosides GT1B [molecular weight (MW) 2129], GM3 (MW 1236), and GD1A (MW 1838) were (mean +/- SEM) 117 +/- 26, 255 +/- 29, and 425 +/- 44 m, respectively. In contrast, the IC50 for GM1 (MW 1547) could not be determined. Incubation of NBL-W cells with epidermal growth factor (EGF) concentrations ranging from 0.1 to 1000 ng/ml progressively increased cell proliferation rate, but it plateaued at concentrations above 10 ng/ml. EGFR tyrosine phosphorylation, however, was incrementally stimulated by EGF concentrations from 1 to 100 ng/ml. The suppression of EGF-induced EGFR phosphorylation differed for each ganglioside, and their respective inhibitory potencies were as follows: EGFR phosphorylation [area under curve (+ EGF)/area under curve (- EGF)]: control (no ganglioside added) = 8.2; GM1 = 8.3; GD1A = 6.7; GM3 = 4.87, and GT1B = 4.09. The lower the ratio, the greater the inhibitory activity of the ganglioside. Gangliosides GD1A and GT1B, which have terminal N-acetyl neuraminic acid moieties, as well as one and two N-acetyl neuraminic acid residues linked to the internal galactose, respectively, both inhibited cell proliferation and EGFR phosphorylation. However, GD1A was a more potent suppressor of cell proliferation and GT1B most effective against EGFR phosphorylation. GM3, which only has a terminal N-acetyl neuraminic acid, inhibited cell proliferation and EGFR phosphorylation almost equivalently. These data suggest that gangliosides differ in their potency as inhibitors of NBL-W neuroblastoma cell proliferation and EGFR tyrosine phosphorylation, and that perturbations in the differential expression of membrane glycosphingolipids may play a role in modulating neuroblastoma growth.