[Effect of the antioxidant ionol on proteolytic apparatus of aging coleoptiles of wheat seedlings grown in light]. / Vliianie antioksidanta ionola na proteolitcheskii apparat stareiushchikh koleoptilei vyrashchivaemykh na svetu prorostkov pshenitsy.

The dynamics of changes in total proteolytic activity and activities of various groups of proteases in the coleoptiles of 3- to 12-day-old wheat seedlings grown in light with and without antioxidant BHT (2,6-di-tert-butyl-4-methylphenol) was studied. It was established that the specialized proteases that easily hydrolyze specific synthetic substrates and the enzymes actively hydrolyzing histone H1 dominate in young coleoptiles of 3- to 4-day-old seedlings. Proteases that degrade equally well the majority of the studied substrates are accumulated in the cells of old coleoptiles of 11- to 12-day-old seedlings. Under the effect of BHT, the plants grown in light (in comparison with etiolated seedlings) demonstrated a somewhat changed dynamics of proteolytic activity in young coleoptiles and the disappearance of proteases active toward histone H1. An inhibitory analysis revealed a relative domination of cysteine proteases in young coleoptiles at the initial development stage of seedlings, whereas the fraction of serine proteases markedly increased in old coleoptiles. We presume that the revealed quantitative and qualitative changes in the proteolytic apparatus of the coleoptile cells induced by BHT may be largely responsible for the retardant and geroprotective effect of this antioxidant in plants.

[DNA-protein cross-links in leukocytes of the field mouse (Apodemus agrarius) and the bank vole (Clethrionomys glareolus) dwelling in the territory of a radioactive waste storage station]. / DNK-belkovye sshivki v leikotsitakh polevykh myshei (Apodemus agrarius) i ryzhikh polevok (Clethrionomys giareolus), obitaiushchikh na territorii punkta zakhoroneniia radioaktivnykh otkhodov.

DNA-protein cross-links in white blood cells of Apodemus agrarius and Clethrionomys glareolus dwelling in the territory of the guarded zone of the radioactive waste storage in Sergievo Posad (area with gamma-background 50-400 microR/h) have been determined. As a control the animals from sanitary protected area of Sergievo Posadsky department (gamma-background on the soil surface is 8-10 microR/h) was used. It was found that the doses received by Apodemus agrarius and Clethrionomys glareolus, resulted in increasing of the DNA-protein cross-link level in the Apodemus agrarius white blood cells by a factor of 1.8, and in Clethrionomys glareolus by a factor of 1.4, in comparison with control. The increase of DNA-protein cross-link number reliably correlates with the beta-emitting nuclide content in animal bodies. The changes in the number white of cells and in the white blood composition were not observed.

[UV-crosslinking of the globular domain of histone H1 with DNA in deoxyribonucleoprotein]. / UF-sshivanie globuliarnogo domena gistona H1 s DNK v dezoksiribonukleoproteide.

UV-irradiated DNP was digested by trypsin to cleave histones, and a crosslinked DNA-peptide complex was isolated. The globular domain of histone HI was found to be linked to DNA. The resistance of the globule to trypsinolysis is discussed with regard to chromatin structure.

[Study of DNA-protein crosslinks induced by UV light in Hela cells]. / Issledovanie UF-svetom indutsirovannykh DNK-belkovykh sshivok v kletkakh Hela.

UV-Irradiation (lambda = 254 nm) of Hela cells in the monolayer causes a dose-dependent formation of DNA-protein crosslinks (DPC). The time-dependent protein increase unaccompanied by a change in the complex yield was observed for the fraction of the DNA-protein complex passing into the aqueous phase by phenol extraction, when the cells were transferred to a fresh culture medium after UV-irradiation. These data suggest that DPC do not repair, while DNA or the protein within the complex can firmly bind additional quantity of protein during the post-irradiation period.

[Chemiluminescence in a toluene-fenoxol scintillation system in the radioreceptor method of researching biological membranes]. / O khemiliuminestsentsii v toluol-fenoksol'noi stsintilliatsionnoi sisteme pri radioretseptornom metode issledovaniia biologicheskikh membran.

The scintillation toluene-fenoxol 8/10 system with ammonia (0.01%) is suggested for radioactive counting in radioreceptor biomembrane assay. It is shown that chemiluminescence in this system is defined mainly by membrane components presence. The remotion of filter from scintillator after labelled molecules elution and methanol (3%) addition to scintillation mixture are suggested to reduce the chemiluminescence level.

[A method for producing peptide maps of picomolar quantities of protein labelled with the Bolton-Hunter reagent in polyacrylamide gel]. / Metod polucheniia peptidnykh kart pikomoliarnykh kolichestv belka, mechennogo reagentom Boltona--Khantera v poliakrilamidnom gele.

A method of radioiodination to high specific activity by Bolton Hunter reagent of fixed and stained histones in polyacrylamide gel is described. The comparative peptide maps of the histones H1 and H3, labelled in solution and the gel are presented.

[Localization of lysine residue in histone H3 forming the thymine-lysine cross-link after UV-irradiation of deoxyribonucleoprotein]. / Lokalizatsiia ostatka lizina v gistone H3, obrazuiushchego timin-lizinovuiu sshivku pri obluchenii dezoksiribonukleoproteida UF-svetom.

A thymine-modified derivative of histone H3 formed as a result of thermal treatment of UV-irradiated (lambda = 254 nm) solution of deoxyribonucleoprotein from calf thymus at low ionic strength was isolated. The peptides obtained by tryptic hydrolysis of modified histone H3 were separated by high pressure liquid chromatography. The amino acid sequence of the peptide containing a lysine residue with covalently linked thymine was determined by the Edman method. It was found that Lys localized at the N-terminus of the histone H3 molecule interacts with DNA within the composition of the deoxyribonucleoprotein.

[Characteristics of sulfhydryl groups of histone H3 from the calf thymus using mercury-containing nitroxyl radicals]. / Kharakteristika sul'fgidril'nykh grupp gistona H3 iz timusa telenka s pomoshch'iu rtut'soderzhashchikh nitroksil'nykh radikalov.

The interaction between total histone and deoxyribonucleoprotein (DNP) preparations from calf thymus with mercury-containing nitroxyl radicals in low ionic strength solutions, 2 M NaCl and urea was investigated. It was found that the label is rapidly incorporated into the SH-groups of histone H3 to produce characteristic EPR signals. Titration of SH-groups within DNP demonstrated that in low ionic strength solutions only one SH-group (presumably, the SH-group of the cysteine residue in position 110) is accessible to the reagents. After dissociation by 2 M NaCl, two SH-groups become titrable; however, the EPR spectra point to differences in the conformational state of these two groups. In 4 M urea, these differences are compensated for by structural disintegration. The spin labels may be used for the analysis of SH-groups under different conditions and at different functional states of nucleoproteins.

[Measurement of the 125I and 14C radioactivity in double-labeled blood samples]. / Izmerenie radioaktivnosti 125I i 14C v dvazhdy mechennykh obraztsakh krovi.

A method for detection of 14C and 125I radioactivity in labeled samples with variable quenching using only liquid scintillation counter is described. Precision, sensitivity and reproduction of this method are comparable with those of the previously used ones, but this method is more suitable and adequate for computerisation.

[The role of histones H3 and H1 in the formation of thymine-lysine cross-links during UV-irradiation of deoxyribonucleoprotein]. / Uchastie gistonov H3 i H1 v obrazovanii timin-lizinovoi shivki pri UF-obluchenii deoksiribonukleoproteida.

The effect of UV light (lambda = 254 nm) on calf thymus DNP at low ionic strengths was studied. It was found that at the irradiation doses used the protein in the DNA-protein complex increases as the irradiation dose rises. Thermal treatment and acid hydrolysis resulted in a predominant release of histones H3 and H1 from the complex. Data from liquid high performance chromatography, amino acid analysis, thin-layer chromatography point to the induction by UV-light of a thymine-lysine bond, whose formation involves DNA thymines and histone lysine residues, predominantly H3 and H1 fractions.

[Dependence of the properties of dioxane-based scintillation systems on the concentration of the components]. / Zavisimost' svoistv stsintilliatsionnykh sistem na osnove dioksana ot kontsentratsii nekotorykh komponentov.

Characteristics of dioxan-based scintillation system have been studied. A composition for scintillation cocktails ensuring an effective homogeneous count of radioactive water samples (0-8% V) at minimum expense of ethyl alcohol has been suggested.

[Comparison of endogenous nuclear RNA-polymerase II at different stages of mycoplasmodial growth]. / Sravnenie éndogennoi RNK-polimerazy II v iadrakh Physarum polycephalum na raznykh stadiiakh rosta mikroplazmodiia.

The nuclei of Physarum polycephalum isolated from the 48- and 96-hour-old growing microplasmodium differ 7-8 fold by the rates of [3H]UTP incorporation in vitro accompanied by a slight (approximately 1.6 fold) change in concentration of endogenous RNA-polymerase II. Using mild fragmentation of chromatin nuclei by micrococcal nuclease and DEAE-Sephadex chromatography the bound enzyme was shown to consist of two forms differing in the degree of their binding to the template and in functional significance. Transcription in the Physarum polycephalum nuclei can be regulated by changes in the correlation of these forms.

[Comparative enzymatic study on the structure of chromatin in the nuclei of the growing microplasmodium of Physarum polycephalum]. / Sravnitel'noe fermentativnoe issledovanie struktury khromatina iader rastushchego mikroplasmodiia Physarum polycephalum.

The structure of chromatin in the growing myxomycetes P. polycephalum can be interpreted on the basis of three types of substructure: (i) soluble in a low ionic strength buffer and 2 mM EDTA (I), (ii) soluble in 0.6 M NaCl (II) and (iii) non-soluble and nuclease-insensitive (III). The ratio of these structures in the nuclear pellet obtained after autolysis was found to be 71 : 0, 4 : 12 for the young and 7.7 : 62 : 20.6 for the old cultures, respectively. The ageing of the culture involves transition of substructure I to substructure II. The substructures differ in the nuclease sensitivity. The specific features of enzyme fragmentation of chromatin from P. polycephalum microplasmodium nuclei are discussed.

[UV-light-tested protein--DNA interactions in the nuclei during the cell cycle in Physarum polycephalum]. / Testiruemye uf-svetom belok--DNK-kontakty v iadrakh na raznykh stadiiakh kletochnogo tsikla Physarum polysephalum.

The release of DNAs from nuclear preparations isolated at different steps of the cell cycle of the synchronous culture of Physarum polycephalum and irradiated with UV-light for 5 min (lambda 253.7 A, i = 1.8 . 10(2) j . m-2 . min-1) into 1% Na-DS - 1.5 M NaCl solution was studied. The value obtained correlated well with the degree of binding of interacting proteins with DNA in chromatin and was identical for all the preparations tested with the only exception of the nuclei isolated at the end of the S-phase, when a slight but significant (15 +/- 10%) increase in DNA release was observed. The results obtained are discussed in terms of structural transitions and function of chromatin during the cell cycle of the myxomycete Physarum polycephalum.

[Changes in DNA-histone contacts under thermal denaturation of DNP and nucleosomes]. / Izmenenie kontakov DNK - gistony pri termicheskoi denaturatsii DNP i nukleosom.

The UV (253.7 nm)-induced binding of the protein to DNA in DNP and nucleosomes at low ionic strength within the temperature range of 5--85 degrees C was studied. A two-step increase in th degree of protein binding was revealed, which was assumed to correspond to two structural conversions in the nucleoproteins during their denaturation. It was shown that the appearance of additional sites of core histone binding in the premelting region is induced by local changes in the DNA structure. None of the four histone fractions was shown to bind preferentially over the whole temperature range studied, which suggests that the structural changes occur all over the length of DNA in the nucleoproteins.

[Effect of UV-light on the structure of soluble deoxyribonucleoprotein-200 A]. / Vliianie uf-sveta na struktupu rastvorimogo dezoksiribonukleoproteida 200 A.

The effects of UV-light (253,7 nm) on the structure of DNP and its protein and nucleic components were studied. The formation of protein-DNA covalent bonds in DNP-200 A at low ionic strength was confirmed. Under certain irradiation conditions more than 80% of protein may be linked to the DNA; all histone fractions were linked to the same extent and at the same rates. The local denaturation of DNA in the region of photo-induced thymine-thymine dimers and other photoadducts dramatically changed the rate and specificity of the effects of staphylococcal nuclease, which directly affected the composition and size of the fragments formed. A possible application of UV-irradiated DNP for various structural investigations is discussed.

[Reaction between tetranitromethane and deoxyribonucleoproteins]. / Vzaimodeistvie tetranitrometana s dezoksiribonukleoproteidami.

A comparative kinetic study has been made of tetranitromethane nitration of tyrosine residues in deoxyribonucleoprotein preparation (DNP) treated with EDTA and/or UV light at lambda=253.7 nm, as well as obtained by enzymatic digestion of nucleosomes. UV-light-induced protein-DNA linkages stabilize the structure of the preparation, whereas the action of chelate agents causes DNP-200 angstrom leads to DNP-100 angstrom transfer. Comparison of kinetic data and the results of the amino acid analysis of individual fractions of nitrated histones allowed to conclude that the differences observed between the degree and the rate of nitration are due to internucleosomic interactions which form the supernucleosomic structure of DNP.