[Comparative study of localization of tryptophanyl-tRNA-synthetase and components of high molecular weight aminoacyl-tRNA-synthetase complex in animal cells]. / Sravnitel'noe izuchenie lokalizatsii triptofanil-tRNK-sintetazy i komponentov vysokomolekuliarnogo aminoatsil-tRNK-sintetaznogo kpmpleksa v kletkakh zhivotnykh.

A comparative study on the localization of cytosolic Trp-tRNA synthetase (TrpRS), aminoacyl-tRNA synthetases associated in a multienzyme complex (Glu-tRNA synthetase (GluRS), and Arg-tRNA synthetase (ArgRS)) and polypeptides p37 and p43 from the multienzyme complex was carried out on ultrathin sections of cultured rabbit cells RK-1 by means of immunogold technique. It is shown that GluRS, ArgRS, and polypeptide p43 have approximately the same distribution in the cell as TrpRS. The data obtained evidences in favour of a multienzyme structure of most (or, may be all) aminoacyl-tRNA synthetases in intact cells. A statistical analysis of enzyme distribution in different cell organelles showed nonrandom, compartmentalized distribution of studied synthetases in the mammalian cell. Aminoacyl-tRNA synthetases were found in the cell nucleus in the vicinity of interchromatin granules and in the regions of diffused chromatin. This fact points to a role which these proteins may play in active chromatin functions (transcription, processing, transfer of gene products, etc.) and needs special attention. Detection of ArgRS and GluRS in the nucleus allows one to suggest that either multienzyme synthetase complexes are present not only in the cytoplasm, but also in the nucleus, or these enzymes can dissociate from the complex and pass to the nucleus as individual proteins.

[The use of RNAse A-colloidal gold complexes for research on RNA-containing cell structures: the effect of different factors on the specificity of the labelling]. / Primenenie kompleksov RNKaza A--kolloidnoe zoloto dlia issledovanii RNK-soderzhashchikh struktur kletki: vliianie razlichnykh faktorov na spetsifichnost' markirovaniia.

Effects of various factors on the specificity and intensity of labelling of RNA-containing structures on the ultrathin sections by RNase A--colloidal gold complexes were studied. The data obtained show that at the optimal choice and standard conditions of labelling the reproducibility of the results is achieved up to 10-20%. It makes it possible to use RNase A-gold method for the quantitative analysis of RNA distribution in the cells at various stages of cell cycle.

[Immune electron microscope determination of the localization of tryptophanyl-tRNA-synthetase in bacteria and higher eukaryotes]. / Immuno-élektronno-mikroskopicheskoe opredelenie lokalizatsii triptofanil-tRNK-sintetazy v kletkakh bakterii i vysshikh éukariot.

Localization of tryptophanyl-tRNA synthetase (TRS) was studied on ultrathin (UT) sections of Escherichia coli cells and of rat fibroblasts fixed with glutaraldehyde and embedded in "Lowicryl K4M" resin at -35 degrees C. The UT sections were treated with the complexes of monoclonal and/or polyclonal antibodies against TRS with colloidal gold 15 and 8 nm in size. In both types of the cells cytoplasm was the most intensely labelled. In fibroblast cytoplasm, zones with a greater amount of ribosomes were mainly labelled, the gold particles being found over both the cysternae of granular endoplasmic reticulum and the areas of localization of free ribosomes. In the zones of microfilament localization TRS was not detected. A great amount of TRS was found in mitochondria and in the fibroblast nuclei. In the latter case, the label was concentrated over the diffuse chromatin localization regions, a minimal binding being observed over compact chromatin. The number of particles observed over diffuse chromatin equals to 50-80% against the label in fibroblast cytoplasm. In contrast, the label used to be absent over the E. coli nucleoid. The presence of TRS in the fibroblast nucleus may evidence in favour of a possible regulatory role of TRS in eukaryots.

[Isolation and fractionation of the nuclear matrix from cultured cells]. / Vydelenie i fraktsionirovanie iadernogo matriksa iz kul'tiviruemykh kletok.

A new method for the isolation of tissue culture cell nuclei is presented which involves incubation of the nuclei in the presence of Cu2+- or Zn2+-ions. This method eliminates the danger of nuclear aggregation and permits nuclear matrix isolation and subsequent fractionation. Stabilization of the inner matrix by Cu2-ions permits analysis of the role of nucleic acids in the maintenance of the matrix structure. It is shown that solubilization of more than 95% of matrix-bound DNA and more than 90% of matrix-bound RNA did not cause any significant changes in the nuclear matrix structure.

[Electron microscope study of changes in the chromatin structure in different functional states of nuclei of a ciliate Bursaria truncatella and a myxomycete Physarum polycephalum]. / Elektronno-mikroskopicheskoe izuchenie strukturnykh izmenenii khromatina v razlichnykh funktsional'nykh sostoianiiakh iadra infuzorii Bursaria truncatella i miksomitseta Physarum polycephalum.

Chromatin structural organization was studied by means of electron microscopy in the macronuclei of ciliate Bursaria truncatella at various stages of the life cycle (at different time intervals after cell division, in resting cysts and at excysting) and in the nuclei of myxomycete Physarum polycephalum during the mitotic cycle. Inactive chromatin was shown to be organized in compact clumps 100-300 nm in diameter linked with each other, their loop organization being convincingly demonstrated. Upon activation chromatin decompacts and is represented by nucleosomal fibres with a lot of replicationally and transcriptionally active regions. Both the reptication and transcription processes in physarum nuclei and transcription processes in bursaria can occur on the loops of chromatin fibres emerging from the decompacting clump. The data obtained evidence in favour of a structural-functional correspondence between the chromatin clumps of physarum and bursaria and the chromomeres in chromosomes of higher eucaryotes. Based on the data received it is concluded that the chromatin clump represents a dynamic structure unit able to decompact forming the loop-shaped chromatin fibres. Such a structural organization provides the spacial distribution of DNA in the nuclei and the possibility of selective functioning of definite regions of the genome.

[Residual chromatin of mouse spleen nuclei after intensive nuclease treatment. Isolation and properties]. / Ostatochnyi khromatin iader selezenki myshi posle intensivnoi obrabotki nukleazoi. Poluchenie i svoistva.

Two-step treatment of mouse spleen nuclei with staphylococcal nuclease was used to isolate residual nuclear structures lacking a considerable part of chromation. Partial disruption of the nuclear envelope after the first step of digestion was shown to be essential for obtaining residual nuclear structures. Isolated residual nuclear structures contained condensed chromatin (residual chromatin) which was not solubilized upon additional staphylococcal nuclease treatment and amounted to approximately 20% of total nuclear chromatin. Residual chromatin was almost deprived of nonhistone chromosomal proteins. It contained a full complement of histones and consisted of nucleosomal chains having different lengths--from one to 50-60 nucleosomes. Some of the condensed chromatin chains were anchored to the nuclear matrix.

[Electron microscopic study of the action of submicroscopic levorin structures on Candida guillermondii]. / Elektronno-mikroskopicheskoe izuchenie deistviia submikroskopiches-kikh struktur levorina na Candida guilliermondii.

In the course of preparation of aqueous solutions of the polyene antibiotic levorin, the latter is recovered in the solid phase forming granular submicroscopic structures. If the cells of Candida guilliermondii are treated with submicroscopic granular structures (SMGS) of levorin, the structures are adsorbed on the surface of the yeast cell walls. Some visible changes occur in the ultrastructure of the yeast cells incubated with SMGS of levorin for 5 min: the inner layer of the cell wall becomes loose, the periplasmic space appears, the cytoplasmic membrane becomes thicker, the mitochondria swell, and fragmentation of the mitochondrial cristae takes place. Dense round alien bodies 20--40 mn in size can be discerned in the periplasmic space of such cells. If the yeast cells are treated with the levorin structures for a longer period of time (15--60 min), the cell ultrastructure is entirely disorganized.

[Fine structure of the outer sheath of the aerial mycelium in Actinomyces levoris]. / Tonkoe stroenie poverkhnostnogo chekhla vozdushnogo mitseliia Actinomyces levoris.

The outer sheath of the aerial mycelium of Actinomyces levoris 64 bears groove-like and granular submicroscopic structures. They are very susceptible to a short-term treatment of the aerial mycelium with aqueous acetone which causes their disintegration. Under specified conditions, submicroscopic structures, viz. granules and threads, assemble from the acetone extract of the aerial mycelium of Actinomyces levoris. These structures possess the anti-yeast activity. The granular structures reorganized from the acetone extract of the aerial mycelium of Actinomyces levoris somewhat resemble in morphology the structures seen in the outer sheath of the aerial mycelium of this actinomycete. The results obtained are discussed within the framework of the hypothesis on a possible participation of polyene antibiotics in the formation of the outer sheath of the aerial mycelium of actinomycetes which produce these antibiotics.

[Makeup of the tubular structures of a stock culture of Act. roseoflavus var. roseofungini]. / Sostav trubchatykh struktur iskhodnoi kul'tury Act. roseoflavus var. roseofungini

The methods of spectral analysis, spectrophotometry, fluorescence and thin-layer chromatography were used for the study of the composition of the tubular structures of the initial culture of Act. roseoflavus var. roseofungini. It was found that they contained a complex of antibiotics (roseofungin and its analogs), Ca, Mg, Na, K, Si and a significant amount of the third non-identified component in the antibiotic complex.

[Production of tubular structures from the aerial mycelium of Actinomyces roseoflavus var. roseofungini]. / Poluchenie trubchatykh struktur iz vozdushnogo mitseliia Actinomyces roseoflavus var. roseofungini

Tubular formations analogous by their structure to those found on the surface of the outer sheath of the hyphae of the aerial mycelium of Actinomyces roseoflavus var. roseofungini were reconstructed in vitro from the mycelium acetone extract on addition of water. A polyenic antibiotic was shown to be present in the composition of the "tubes". A possible role of the antibiotic in the genesis of the secondary structures of the actinomycete is discussed.

[Conditions for the self-organization of submicroscopic structures from mycelial extracts of the "fructose" variant of Actinomyces roseflavus var. roseofungini]. / Usloviia samoorganizatsii submikroskopicheskikh struktur iz ékstraktov mitseliia "fruktoznogo" varianta Actinomyces roseoflavus var. roseofungini

Self-organization of various submicroscopic formations, such as "tubes", "ribbons", etc. differing in ultrastructure and containing a polyenic antibiotic was observed in acetone extracts of the mycelium of the "fructose" variant of Actinomyces roseoflavus var. roseofungini. Conditions for separate isolation of the above structures are described. Concentration of the extract and the ratio of the volumes of water added to the extract are determinant for the process of self-organization. A possibility of reorganization of the tubular structures into the ribbon-like ones and vice versa is shown.

[Self-assembly of extracellular tubular structures of non-protein nature produced by an actinomycete]. / Samoorganizatsiia vnekletochnykh trubchatykh struktur nebelkovoi prirody, obrazuemykh aktinomitsetom

When grown on the solid synthetic medium with glucose as the only carbon source the dedifferentiated "fructose" mutant of Actinomyces roseoflavus var. roseofungini accumulated aggregates of tubular-like structures. The individual tubules had the internal diametre of 80 A and external diametre of approximately 200-220 A. These structures were isolated as a distinct fraction and their non-protein nature was demonstrated. They were easily soluble in acetone and reconstitutable in vitro. The possible significance of production of self-assembling structures by a mutant with impaired differentiation is discussed. The possibility of involvement of self-assembly processes in the formation of surface sheath of aerial mycelium in normally differentiating actinomycetes is mentioned.