Changes in the two-dimensional proteome of the soluble fraction of nuclear proteins from Lepidium sativum root meristematic cells grown under clinorotation.

The changes in the fundamental biological processes of nuclear RNA transcription and splicing under altered gravity conditions are still unclear. The quantitative and qualitative characteristics of the proteins involved in nuclear RNA metabolism in control and under clinorotation were investigated by two-dimensional gel electrophoresis. We revealed firstly a decrease in the isoelectric point range of nuclear soluble proteins, which are known to be actively engaged in nuclear RNA metabolism, and a shortening in the molecular weight range of them under clinorotation. Moreover, minor and major proteins in clinorotated samples had decreased optical densities in comparison with control ones. Our results are in agreement with the hypothesis that a rearrangement of the pattern of nuclear proteins involved in gene expression processes occurs in seedlings grown and developed in altered gravity.

[Alterations of nucleolar DNA localization caused by simulated microgravity].

The functions of the nucleolus responsible for the biosynthesis of ribosomes in altered gravity are still unclear. The location of nucleolar DNA both in control and simulated microgravity has been investigated using fluorescent and immunogold cytochemistry. We have determined the redistribution of rDNA in the nucleolar components accompanied by their ultrastructure changes. According to this the lowering of rDNA transcription level under simulated microgravity was supposed.

[Altered gravity affects subnucleolus localization of fibrillarin and NopA64, the most important proteins of rRNA processing].

Fibrillarin and plant nucleolin homologue NopA64 are two important nucleolar proteins involved in pre-rRNA processing. To understand better the effects of the altered gravity environment on the nucleolus functioning we have investigated the location of fibrillarin and NopA64 in nucleolar subcomponents of cress (Lepidium sativum L.) root meristematic cells grown under simulated microgravity that was compared to the control cells grown in normal conditions at I g. Cress fibrillarin was first shown to have the molecular weight 41 kDa. Both fibrillarin and NopA64 in the cress cell nucleolus are located in the zones known to contain processing pre-rRNA molecules as it has been previously reported in other species. The data confirm participation of these proteins in processomes--RNP complex particles involved in pre-rRNA processing. Under altered gravity a decrease in the quantity of both fibrillarin and NopA64 in the transition zone between fibrillar centres and the dense fibrillar component was observed, compared to control, which could point out to a lowering of the level of early pre-rRNA processing in these experimental conditions. This decrease was also detected in the bulk of the dense fibrillar component. These data support the idea that altered (reduced) gravity results in lowering the level of functional activity of the nucleolus.

Alterations of the intranucleolar DNA localization caused by simulated microgravity.

The functions of the nucleolus responsible for the biosynthesis of ribosomes in altered gravity are still unclear. The location of nucleolar DNA both in control and simulated microgravity with fluorescent and immunogold cytochemistry was investigated. We determined firstly the redistribution of rDNA in the nucleolar components accompanied with the changes in their ultrastructure. According to it, lowering the level of rDNA transcription in simulated microgravity was firstly proposed.

[Effect of changes in gravity on the quantity and localization of fibrillarin in the nucleolus of cress root meristem]. / Vliianie izmenennoi gravitatsii na kolichestvo i lokalizatsiiu fibrillarina v iadryshkakh kornevoi meristemy kress-salata.

For the first time, in altered gravity, with antifibrillarin antibodies and immunogold microscopy fibrillarin that is one of the most important proteins of rRNA processing was localized. The quantitative study of the density of gold particles in the nuclelous, under clinorotation both the transition zone FC-DFC and the dense fibrillar component were less labeled as compared to the control. Obtained data allow us to suppose the lowering of the rRNA processing level in the nucleoli under the influence of altered gravity.

Nucleolar structure and function under clinorotation.

A nucleolus is the dynamic part of a cell nucleus where rDNA transcription, rRNA precursor processing and transport are proceeding. Investigations of the influence of microgravity and clinorotation on the structure and function of nucleolus began more than thirty years ago but, unfortunately, now there are only some articles concerning the nucleolar peculiarities in altered gravity. Available data about alterations of nucleolar morphology and function under the influence of high and low temperature, hypoxia and UV-microbeam irradiation allow us to put intent attention to the study of the nucleolus reactions on clinorotation. Therefore, the aim of our work was to investigate the ultrastructural organization and functional activity of nucleoli in Lepidium sativum root meristematic cells under clinorotation in order to understand whether a nucleolus can react to gravity.

[Role of the nucleolus in plant cell response to environmental physical factors]. / Rol' iadrishka v reaktsiiakh rastitel'nykh kletok na deistvie fizicheskikh faktorov okruzhaiushchei sredy.

Contemporary data on ultrastructural reconstruction and changes in functional nucleolus activity in plant cells affected by physical environmental factors are presented. The main attention is paid to modifications of ribosomal gene expression under these conditions and induced changes in r-chromatin structure and ribosomal DNA localization. Recent data on fine nucleolus structure and molecular aspects of its organization as well as influence of microgravitation and clinostating on structural and functional organization of plant nucleoli are reported.

[Microflora of the sputum and indicators of natural resistance in patients with acute pneumonia]. / Mikroflora mokroty i pokazateli estestvennoi rezistentnosti u bol'nykh ostroi pnevmoniei.

The paper is concerned with the results of quantitative studies on the sputum of 106 patients with acute pneumonia. Etiological structure of acute pneumonia, the dependence of a clinical course of disease on a sputum microflora composition type and some indices of natural resistance and immunity were shown.