Experimental results of daily counting under a microscope for 30 days of prokaryotic cells in preparations from soil samples when stained with different specific dyes and literary results on daily counting of bacteria in soil using different methods are presented. The FITC dye, which stains the entire set of bacterial cells, revealed a wave-like dynamics of cell numbers with different numbers of oscillations in the form of peaks in all experiments. Using the SFDA dye, which detects only living, metabolically active cells, wave-like dynamics were also revealed, but their oscillating number was significantly less. The reliability of oscillations and differences in cell numbers when using different dyes were confirmed statistically and by harmonic analysis. The wave-like dynamics of living, metabolically active cells is a consequence of the cycles of growth and death of bacterial cells and short-term trophic succession in the microbial community. External disturbing influences did not affect the manifestation of wave-like population dynamics, both in the population of living cells and in the total number of cells. The phenomenon of wave-like dynamics of non-living bacterial cells and their numerical superiority is explained by the fact that cells, losing viability, lyse and disintegrate not immediately after dying, but with some delay in time. This leads to the accumulation and permanent superiority of the pool of dead cells when microscopically counting the total number of bacteria in the soil and explains the discrepancy in bacterial numbers between different counting methods. The presented experimental and literary material will serve as a substantiation for microbiologists and biotechnologists of the need to control the dynamics of the numbers of introduced populations and communities of microorganisms into the natural environment, as well as a source of knowledge for the successful management of natural microbial communities.

The objectivity of the phenomenon of wave-like changes in the number of cells of microbial populations and communities in nature or in a pure culture of microorganisms and the significance of understanding this phenomenon for ecology and biotechnology are experimentally and theoretically substantiated. A brief history of the problem is discussed. Three basic general laws of population ecology are given. A mathematical model is proposed, which, based on the parameters included in the equations, makes it possible to describe the wave-like dynamics of the growth of a population of a pure bacterial culture. This model is a mathematical expression of the third law of population ecology, reflecting the dynamics of the existence of a pure culture of microorganisms: dX/dt = (µ(S) −D(S)) × X. dS/dt = −X × µ (S)/Y + K r × X × D(S). The experimental and theoretical material presented in the work will be of interest to microbiologists, biotechnologists—theorists and practitioners in the field of cultivation of microorganisms—and specialists in the field of population ecology.

Stochastic gene expression can play an important role in the fate of both each specific cell and the cell population as a whole. In this work, we demonstrate significant variability of p53 expression, up to its complete absence, in human primary glioblastoma cells, which is not observed in cells of normal FLEH fibroblasts and transferable tumour cell lines, such as HeLa and HT1080. At the same time, the variability of p53 expression in cells depends on the density of seeding. We show that when the transcription is suppressed with actinomycin D or the p53 gene is knocked down by RNA interference, the restoration of its expression level in cells proceeds stochastically.

The problem of localizing the zeros of analytic functions using the Krawczyk operator is considered. Formulas are obtained for computing the image of the Krawczyk operator for analytic functions. Based on this, a new algorithm for localizing the zeros is proposed. The use of the method is demonstrated by numerical examples including the search for the zeros of the Riemann zeta function.

It is proposed that soil should be considered a biological system with the following notions: “soil ecosystem” or “ecosystem of soil.” A new, integral characteristic of the soil ecosystem—soil health—is addressed. Parameters and methods essential to define soil health and characterize this new category are provided. Natural soil ecosystems and agroecosystems are discussed and compared. Conventional and organic land use systems are addressed in relation to agroecosystems. The need to determine and assess the health of soil ecosystems with respect to the land-use type is highlighted. Activities and methods required to preserve and protect the health of soil ecosystems, the significance of “activity suppression” in soil ecosystems, and means to diagnose soil health and to use therapy in modern agroecosystems are discussed.

We present a survey of the latest results obtained in the field of numerical solutions of unstable integral and pseudodifferential equations. New versions of fully discrete projection and collocation methods are constructed and justified. It is shown that these versions are characterized by the optimal accuracy and cost efficiency, as far as the use of the computational resources is concerned.

Although there is a progress in understanding the causes and consequences of genetic and epigenetic changes in glioma malignant transformation, many details remain obscure and need further investigation. It is known that process of malignant transformation of gliomas is accompanied by gradual loss of LGI1 gene expression. However, genetic defects causing LGI1 inactivation have not been revealed. In this paper, we have analyzed the LGI1 gene expression in primary cultures of malignant gliomas, and compared these data with epigenetic indicators of transcriptional activity — posttranslational H3 histone modifications. We have show the presence of an epigenetic marker of gene repression H3K9me3 near the site of LGI1 transcription initiation in most (5 from 6) studied gliomas. There was not LGI1 expression in these gliomas. Only one glioma showed LGI1 expression, and in this glioma there was no association of LGI1gene with H3K9me3 modification. Thus, we are the first to show a correlation between LGI1 gene expression and the epigenetic indicator H3K9met3 in malignant gliomas. Marker of actively transcribed chromatin Í3K4àñ have not been found in this area of the genome. The data obtained strongly suggest the possibility of gene LGL1 inactivation by epigenetic mechanism: modified «histone code».

The issue of informational complexity for exponentially ill-posed problems is considered. The investigation is performed for Fredholm integral equations of the first kind with finite-smoothness operators. The proposed projection method allows to achieve optimal order accuracy for a posteriori selection of regularization parameter by balancing principle. Moreover such approach saves minimal volume of informational efforts.

The reduction of arithmetical operations for the solving of periodic integral equations with minimal error bound is considered. For this some modification of a fully discrete projection method was proposed. It was proved that such modification guarantees the best possible accuracy of the numerical method in the metric of Sobolev spaces with the order of arithmetical operations N log N

Both genetic and epigenetic changes underlie the mechanisms of tumor initiation and progression. In this study, we analyzed sox2 gene expression and its epigenetic changes in primary cultures of malignant gliomas. The sox2 expression was detected in most (74%) gliomas, but not in morphologically normal brain tissue. These facts point to relationships between the sox2 transcription activity and the process of glioma malignant transformation. It was demonstrated that association of different areas of the sox2 gene with important epigenetic markers—posttranslational modifications of H3 histone H3K4ac and H3K9met3—did not correlate with sox2 expression. However, it suggests stochastic regulation of sox2 gene expression in malignant gliomas.

Malignant gliomas are aggressive and highly invasive tumors. Various genetic and epigenetic changes are common for these tumors. Mostly they concern the genes involved in cell-cycle regulation, apoptotic pathways, cell invasion, angiogenesis, and cell metabolism. The role of epigenetic mechanisms in glioma malignant transformation, despite recent progress, is uncertain and remains under intense study. This review describes the mechanisms of epigenetic regulation of gene expression, including posttranslational modifications of histones, DNA methylation in promoter regions, and microRNA regulation. The genetic and epigenetic factors driving the pathogenesis of gliomas in their possible mutual influence and the potential epigenetic targets that can be used for diagnostics and new therapeutic approaches are also discussed.

The daily dynamics of the number of copiotrophic and oligotrophic bacteria (in colony-forming units) and CO 2 emissions from cultivated soils after short- and long-term disturbances were studied for 25–27 days in a microfield experiment. The relationship of the wavelike fluctuations of the bacterial number and CO 2 emission with the succession of the soil microbial community was determined by the polymerase chain reaction method—denaturing gradient gel electrophoresis (PCR-DGGE). Short-term disturbances involved the application of organic or mineral fertilizers, pesticides, and plant residues to the soils of different plots. The long-term effect was a result of using biological and intensive farming systems for three years. The short-term disturbances resulted in increased peaks of the bacterial number, the significance of which was confirmed by harmonics analysis. The daily dynamics of the structure of the soil microbial community, which was studied for 27 days by the DGGE method, also had an oscillatory pattern. Statistical processing of the data (principal components analysis, harmonics and cross-correlation analyses) has revealed significant fluctuations in the structure of microbial communities coinciding with those of the bacterial populations. The structure of the microbial community changed within each peak of the dynamics of the bacterial number (but not from peak to peak), pointing to the cyclical character of the short-term succession. The long-term effects resulted in a less intense response of the microbiota—a lower rate of CO 2 emission from the soil cultivated according to the organic farming system.

BACKGROUND:Deletions and duplications of single exons or exon groups account for a large proportion of the PARK2 gene mutations described in juvenile autosomal recessive Parkinson's disease (PD). METHODS:We analyzed rearrangements in exons 1 to 12 of the PARK2 gene in Russian sporadic patients with early-onset PD (EOPD) and late-onset PD (LOPD). RESULTS:The frequency of EOPD and LOPD patients carrying these mutations was 12.4% and 3.8%, respectively. The most frequent rearrangements were detected in exons 3 and 4. The odds ratio for EOPD in individuals carrying PARK2 exon deletions and duplications was 13.95 (95% confidence interval [CI], 1.846-105.46; P = .0022). In addition, we found a correlation between exon rearrangements in PARK2 and the age at onset of PD, presence of dystonia, and symmetrical course of the disease. CONCLUSIONS:Exon rearrangements in the PARK2 gene play a significant role in the pathogenesis of sporadic PD in Russian patients.

To date, the mechanisms responsible for radical change of chromatin structure in male germ cells during fertilization are unclear. Evidence suggesting the existence of proteolytic nuclear enzymes in mature human spermatozoids are presented in this work. The possible role of these previously unknown proteases in decondensation of chromatin of spermatozoids in a fertilized ovum is discussed. Application of the flow cytometry technique has shown that treatment of human spermatozoid nuclei with SH-reagents leads not only to destruction of disulfide bonds between protamine molecules that is necessary for their effective utilization but also induces specific endogenous proteolytic activity that consequently results in rather fast decondensation of chromatin followed by proteolytic cleavage of nuclear proteins. A chromatin decondensation process can be almost totally blocked by serine protease inhibitors and components of seminal fluid. An original cytochemical approach of binding of fluorescently labeled protease inhibitor to the target of investigation has been used in order to visualize the localization of proteases in male germ cell nuclei. The results of our study suggest that one of the factors of chromatin reorganization involved in the formation of male pronucleus is endogenous nuclear protease of spermatozoids, which is activated by glutathione or other SH-components of ovum cytoplasm.

AbstractThe paper considers a method for solving nonlinear ill-posed problems with monotone operators. The approach combines the Lavrentiev method, the fixedpoint method, and the balancing principle for selection of the regularization parameter. The method’s optimality has been proved for some set of smooth solutions. A test example proves the efficiency of the proposed method.

Cardiomyopathy and neuropathy are the two commonly observed complications in diphtheria patients and in, some instances, individuals vaccinated against diphtheria. The nature of these complications remains not well understood. It was suggested that autoimmunity may play a role in the development of these afflictions. Based on functional similarities between diphtheria toxin (DT) and epidermal growth factor receptor (EGFR), which both can bind to the heparin-binding EGF-like growth factor (HB-EGF) precursors, we suggested that antibodies developed against DT can cross react with EGFR. Here, using serum from healthy donors (n = 10) and diphtheria patients (n = 15), we demonstrated that B-subunit of DT has the antigenic epitopes similar to those of EGFR. Diphtheria toxin as well as EGFR could be recognized by antibodies raised against EGFR and by serum antibodies from diphtheria patients. Moreover serum of diphtheria patients competitively inhibits binding of anti-EGFR antibodies to the receptor. The truncated diphtheria toxin without B-subunit could be detected by serum antibodies of diphtheria patients, but not by anti-EGFR antibodies. Collectively, these studies demonstrate cross-reactivity of antibodies raised against B-subunit of DT and extracellular domain of EGFR and suggest that clinically observed post-diphtheria complications may result from autoimmune inhibition of EGFR function and possible destruction of receptor-positive tissues.