[Analytical characteristics micromatrix semiquantitative method used in serial tests with video digital registration].

A multiplex analytical system has been developed to carry out microformat latex agglutination tests with video digital registration. The system makes it possible to apply less than 1 microl drops of latex and samples in the matrix format to a carrier and to make the test in 30 points at once, as well as to record and to interpret the results of the test, by keeping analytical information for each sample. Comparison of the results of determination of the serum levels of C-reactive protein, rheumatoid factor, and antistreptolysine in the system developed by the authors with the results obtained in the macroagglutination test by the immunoturbidimetric technique leads to the conclusion that the methods are comparable. The proposed type of a latex agglutination test based on a matrix approach and miniaturization assures efficient production and the quality of laboratory studies.

[Use of a scanner to register the results of enzyme immunoassay in the standard microplates].

Whether a commercially available scanner might be used as a vertical photometer of 96-well microplates for enzyme immunoassay (EIA) was studied. The analytical characteristics of the scanner in this regard were assessed, by comparing the findings with the respective photometric data obtained by a "VICTOR" EIA analyzer. It is concluded that the scanner registration system in combination with "Expert-Lab EIA" may be used in all types of EIA. The scanner system provides additional possibilities as compared with the conventional photometric analyzers.

[A scanner-based system for documentation, objective assessment, and recording of the results of latex-agglutination tests].

The present paper describes the use of the scanner "Expert-Lab Agglutination" system to record the results of latex-agglutination tests in making a reaction on the lids of 96-well immunoassay plates. The described system provides a possibility of having a primary image of all tests carried out on a carrier. Software offers the prospect of contrasting the images of individual and control samples, increasing the size of images, and comparing the latter. The use of special image treating techniques may also yield objective figures characterizing the rate of a reaction. The possibility of archiving primary information and retrospectively appraising the correctness of the result of an analysis at any required moment is of fundamental importance to the latex-agglutination test.

[Effect of supporting substrates on the structure of DNA and DNA-trivaline complexes studied by atomic force microscopy]. / Vliianie podlozhek pri atomno-silovoi mikroskopii DNK i kompleksov DNK s trivalinom na ikh strukturu.

Linear DNA, circular DNA, and circular DNA complexes with trivaline (TV), a synthetic oligopeptide, were imaged by atomic force microscopy (AFM) using mica as a conventional supporting substrate and modified highly ordered pyrolytic graphite (HOPG) as an alternative substrate. A method of modifying the HOPG surface was developed that enabled the adsorption of DNA and DNA-TV complexes onto this surface. On mica, both purified DNA and DNA-TV complexes were shown to undergo significant structural distortions: DNA molecules decrease in height and DNA-TP displays substantial changes in the shape of its circular compact structures. Use of the HOPG support helps preserve the structural integrity of the complexes and increase the measured height of DNA molecules up to 2 nm. AFM with the HOPG support was shown to efficiently reveal the particular points of the complexes where, according to known models of their organization, a great number of bent DNA fibers meet. These results provide additional information on DNA organization in its complexes with TV and are also of methodological interest, since the use of the modified HOPG may widen the possibilities of AFM in studying DNA and its complexes with various ligands.

[Morphologic and physiologic-biochemical characterization of Pseudomonas aeruginosa dissociation variants]. / Morfologicheskie i fiziologo-biokhimicheskie osobennosti dissotsiantov Pseudomonas aeruginosa.

Populations of the hydrocarbon-oxidizing strain K-2 of Pseudomonas aeruginosa dissociate into R, S, and M variants. They differ in colony morphology, cell fine structure, and cell yields on synthetic medium with hexadecane and on nutrient broth mixed with wort (NB + W). The best growth on NB + W was shown by the R variant, while the highest cell yield on hexadecane medium (exceeding that of the original culture) was attained by the S variant.

[The hierarchy of complexes and compact structures of trivaline with nucleic acids. III. Complexes of trivaline with trinucleotides forms a rod-like structure with length of about 1000 A in solution]. / Ob ierarkhii kompleksov i kompaktnykh struktur trivalina s nukleinovymi kislotami. III. Kompleksy trivalina s trinukleotidami obrazuiut v rastvore palochkoobraznye struktury dlinoi 1000 A]

We demonstrated the ability of trivaline in the course of interaction with certain trinucleotides in solution to form extended fibre-like structures with lengths of up to several thousand angstroms. Such structures were observed for complexes of trivaline with both deoxyribo- and ribonucleotides with homopurine, homopyrimidine, or random sequences, with or without terminal 5'-phosphate. A model of organization of such structures is proposed. It is based on tetramer complex of trivaline with short nucleotides, two structural units of which, consisting of trivaline tetramer and two trinucleotides, form the octamer complex. It has three perpendicular axes of symmetry of the second order. The spatial location of bases in this structure is additionally fixed by nucleopeptide interactions. The latter create favourable conditions for arranging hydrogen bonds between trinucleotides belonging to different tetramer complexes and stacking interactions between the bases of each nucleotide. Octamer complexes are able to form regular aggregates in the form of a "stack", consisting of dozens of elementary units. These aggregates can be electron microscopically visualized as extended fibre-like structures.

[Genomic DNA as compact particles: morphology, biochemical analysis and optical properties]. / Genomnaia DNK v forme kompaktnykh chastits: morfologiia, biokhimicheskii analiz i opticheskie svoistva.

Compact DNA particles have been obtained by a new method we developed to isolate high-molecular-weight DNA. The method includes exhaustive proteolysis while the cellular DNA is folded in compact state in polyethylene glycol-containing aqueous-salt media. The DNA particles derived from interphase nuclei have a diameter of 8-10 microns and each of them contains the genome of an individual cell. The DNA particles derived from isolated metaphase chromosomes present tightly packed DNA of individual chromosomes. The compact particles contain no proteins detectable by electrophoretic analysis and so appear to be formed by DNA only. These data have been confirmed by electron microscopy, when the particles investigated with the protein monolayer technique have revealed only spread DNA molecules. Simultaneously the microscopic observations of DNA particles of different origin and of their behaviour in the absence of compactizing agents support the idea that during formation of compact particles the intrinsic features of DNA folding in nuclei and chromosomes have been conserved.

[Electron microscopic study of DNA compactization under the effect of putrescine]. / Elektronno-mikroskopicheskoe izuchenie kompaktizatsii DNK pod deistviem putrestsina.

DNA-putrescine complexes were studied by electron-microscopy with the use of protein-free method. The latter gives the opportunity to investigate the interaction of DNA molecules spread on the surface layer of hypophase and the polyamine molecules in the thick layer of hypophase. Polyamine concentration varied from 5 x 10(-4) mM to 5 x 10(-1) mM. Under the low concentration of putrescine the complexes are represented by agglomerations of kinked knobbed fibres 10 to 20 nm thick, consisting of several fibres of duplex DNA. Upon increasing of putrescine concentration from 5 x 10(-4) to 1.5 x 10(-1) mM, the fibres become more thick (up to 25 nm), highly twisted and have the appearance of cylinders. Very often in the composition of complexes, it is possible to encounter the circular structures, which were formed at the expense of intermolecular interaction of different parts of the complex. The circular structures can serve as "embryos" of toroids of different sizes, that is of different degree of saturation with DNA and putrescine. At the concentration of putrescine 5 x 10(-1) mM the complexes have the appearance of toroids and structures on the basis of toroids, cylinders. The scheme of possible transitions of fibres of various thickness is proposed. The regularities of the compactization process, stimulated by polyamines, don't depend on the degree of compactization (the thickness of compacting fibre), that is they are similar for duplex DNA and for the fibres 25 nm thick, consisting of dozens of DNA molecules.

[Ultrastructural features of Rhodococcus rubropertinctus and Streptococcus lactis dissociants]. / Ul'trastrukturnye osobennosti dissotsiantov Rhodococcus rubropertinctus and Streptococcus lactis.

Three Rhodococcus rubropertinctus dissociants (R, S and M) and two Streptococcus lactis dissociants (R and S) were compared using the electron microscopy method of negative contrasting. The cell wall of R.rubropertinctus dissociants had a thickness of 40 nm (R), 30 nm (S) and 20 nm (M). The cell wall of S. lactis dissociants was 35-55 nm (R) and 25-30 nm (S) thick. 1.5-2-fold variations in the thickness of cell walls could account for the different resistance of the dissociants against the action of such external factors as dehydration, antibiotics, UV, elevated NaCl concentrations, etc.

[Structural organization of kinetoplast DNA and its compactization in a model system in vitro]. / Strukturnaia organizatsiia kinetoplastnoi DNK i ee kompaktizatsiia v model'noi sisteme in vitro.

Studies on compactization and decompactization of the genome are of great importance for elucidation of structural mechanisms taking part in the regulation of gene activity. Kinetoplast DNA (kpDNA) is a convenient model for studies of compactization processes. KpDNA represents unique structure ("network"), consisting of catenated circular molecules of two types: minicircles (900 b.p.) and maxicircles (40 000 b.p.). The compactization process of kpDNA in vitro caused by interaction with synthetic peptide-dansylhydraside trivaline was studied. It was shown that at the initial stages the hairpins are observed on minicircles as if triple rings are being organized. The formation of hairpin is probably favoured by the presence in the minicircles of bent DNA, a specific nucleotide sequence causing rigid bending of the DNA helix. The hairpin does not make contact with the neighbouring DNA segment to form a triple ring, because the sizes of minicircles are too small. The minicircles compactization is finished with a complete collapse of the minicircles with the formation of rod-like structures. The catenation causes branching of rod-like structures. As a result of their intermolecular interaction, the branched rod-like structures become thicker. The process is completed with formation of the compact network, its diameter being 3-6 times smaller compared to the initial one.

[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.

[Structure of the macronucleus chromatin of the ciliate Bursaria truncatella. III. Chromatin organization in resting cysts and during excysting]. / Struktura khromatina makronukleusa infuzorii Bursaria truncatella. III. Strukturnaia organizatsiia khromatina v tsistakh pokoia i v protsesse ékstsistirovaniia.

Structural organization of macronuclear chromatin of a ciliate Bursaria truncatella was studied electronmicroscopically by means of Miller's technique and negative staining of resting cysts and at excysting. In resting cysts practically all the macronuclear chromatin was shown to be organized into compact chromatin clumps 100-300 nm in size. At excysting a natural decompactization of the chromatin clumps occurred and radial loop-shaped chromatin fibres appeared around the clumps. Sometimes transcription units with a relatively small contour length of transcribed region and with high RNA-polymerase density were observed on the loops. The responsibility of such genes for the synthesis of proteins taking part in regulation of excystment and/or subsequent cell growth and differentiation is discussed.

[Structure of the interphase chromatin in the ciliata Bursaria truncatella macronucleus. II. Loop organization of inactive chromatin clumps]. / Struktura interfaznogo khromatina makronukleusa infuzorii Bursaria truncatella. II. Petel'naia organizatsiia glybok neaktivnogo khromatina.

Electron microscopic study of chromatin organization in isolated macronuclei of a ciliate Bursaria truncatella showed macronuclear chromatin to be organized in compact clumps 120--180 nm in diameter linked with each other by one or several chromatin fibres. Macronucleus being dispersed in a solution of low ionic strength, radial loops basically of nucleosomal structure start appearing around chromatin clumps. Long-time dispersing of macronuclear chromatin brings complete decompactization of chromatin clumps into a set of nucleosome fibres. The way the fibres of interphase chromatin are packed in a chromatin clump is discussed.

[Structure of the interphase chromatin in Bursaria truncatella macronucleus. I. Electron microscopic and autoradiographic study of the structural chromatin changes during differentiation and growth after division]. / Struktura interfaznogo khromatina makronukleusa infuzorii Bursaria truncatella. I. Elektronno-mikroskopicheskoe i avtoradiograficheskoe izuchenie strukturnykh izmenenii khromatina v protsesse differentsirovki i rosta infuzorii posle deleniia.

The structure of interphase chromatin from isolated individual macronuclei of Bursaria truncatella was studied at different moments after cell division. During the period 0,5-3 hours after division most of the macronuclear chromatin is represented by loose agglomerations of decondensed chromatin, where transcription complexes can be seen. The maximum quantity of decondensed chromatin is observed 0,5-1,5 hours after cell division. During the period 1,5-3 hours after the division the part of decondensed chromatin decreases along with the increase of the quantity of dense chromatin organized in chromatin clumps 0,12-0,18 mu in diameter. In completely developed vegetative cells nearly all the chromatin has the structure of closely packed chromatin clumps. Electronmicroscopic autoradiography data show that chromatin clumps are transcriptionally inert, whereas all the transcription processes take place in decondensed chromatin agglomerations. The structure of transcription complexes of B. truncatella macronucleus is discussed in detail.