Encapsulated Hsp70 decreases endotoxin-induced production of ROS and TNFα in human phagocytes.

Human heat shock protein Hsp70 was experimentally inserted into polyelectrolyte microcapsules. Encapsulated recombinant Hsp70 was studied in terms of its effects on neutrophil apoptosis, the production of reactive oxygen species, and the secretion of tumor necrosis factor alpha by promonocytic THP-1 cells. It was found that encapsulated Hsp70 effectively inhibits neutrophil apoptosis, unlike free exogenous protein used in solution.

Influence of encapsulated heat shock protein HSP70 on the basic functional properties of blood phagocytes.

Microencapsulated heat shock proteins HSP 70 were studied in terms of their effects on neutrophil apoptosis, production of reactive oxygen species, and secretion of TNF-α by human neurtrophils and monocytes. Encapsulated HSP70 inhibited neutrophil apoptosis by 65% as compared to the effect of nonencapsulated HSP70; TNF-α production by the promonocytic THP-1 cells was similarly inhibited by the non-encapsulated and encapsulated HSP70. Thus, the polyelectrolyte micromolecules can be used as containers for effective delivery of HSP70 up to neutrophils and monocytes to correct the innate immunity functions.

Particle-based optical sensing of intracellular ions at the example of calcium - what are the experimental pitfalls?

Colloidal particles with fluorescence read-out are commonly used as sensors for the quantitative determination of ions. Calcium, for example, is a biologically highly relevant ion in signaling, and thus knowledge of its spatio-temporal distribution inside cells would offer important experimental data. However, the use of particle-based intracellular sensors for ion detection is not straightforward.

[Inclusion of proteins into polyelectrolyte microcapsules by coprecipitation and adsorption].

In present study microcapsules composed of synthetic (PSS and PAA) and biodegradable (DS and PAr) polyelectrolytes on calcium carbonate microparticles were obtained. The ultrastructural organization of biodegradable microcapsules was studied using transmission electron microscopy. The envelope of such capsules consisting of six polyelectrolyte layers is already well-formed, having the average thickness of 44 ± 3.

Chemosensors and biosensors based on polyelectrolyte microcapsules containing fluorescent dyes and enzymes.

The concept of enzyme-assisted substrate sensing based on use of fluorescent markers to detect the products of enzymatic reaction has been investigated by fabrication of micron-scale polyelectrolyte capsules containing enzymes and dyes in one entity. Microcapsules approximately 5 μm in size entrap glucose oxidase or lactate oxidase, with peroxidase, together with the corresponding markers Tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) dichloride (Ru(dpp)) complex and dihydrorhodamine 123 (DHR123), which are sensitive to oxygen and hydrogen peroxide, respectively. These capsules are produced by co-precipitation of calcium carbonate particles with the enzyme followed by layer-by-layer assembly of polyelectrolytes over the surface of the particles and incorporation of the dye in the capsule interior or in the multilayer shell.

[Distribution of proteins inside polyelectrolyte microcapsules depend on pH of medium].

Distribution of bovine serum albumin and ferritin inside polyelectrolyte microcapsules was studied by transmission electron and confocal microscopy at the pH range 2-5. It was estimate that protein's distribution depends on isoelectric point (pI) and first polyelectrolyte used for preparation of capsule shell. So peptide is placed in the bulk of capsule if pH values of medium are lower isoelectric point of protein and polycation was used as a first polyelectrolyte layer.

Co-encapsulation of enzyme and sensitive dye as a tool for fabrication of microcapsule based sensor for urea measuring.

Enzyme based micron sized sensing system with optical readout was fabricated by co-encapsulation of urease and dextran couple with pH sensitive dye SNARF-1 into polyelectrolyte multilayer capsules. Co-precipitation of calcium carbonate, urease and dextran followed up by multilayer film coating and Ca-extracting by EDTA resulted in the formation of 3.5-4 micron capsules, what enable the calibrated fluorescence response to urea in concentration range from 10(-6) to 10(-1) M.

[Investigation of the influence of temperature on polyelectrolyte microcapsules containing and not containing proteins].

Using the methods of light scattering and optical microscopy, data on the thermosensitivity of hollow microcapsules generated by alternative layers of poly(allylamine) and poly(sterenesulfonate) polyelectrolyte and microcapsules with included polyelectrolyte complexes and proteins have been obtained. It has been shown that all three types of capsules shrink with increasing temperature and the time interval of thermal influence, and their diameter decreases. The thermosensitivity has been estimated by means of the temperature factor of shell shrinkage (Ec).

[Incapsulation of enzymes into polyelectrolyte nano- and microcapsules and the problem of the development of enzymatic microdiagnostics].

The incapsulation of proteins into polyelectrolyte microcapsules (PE-microcapsules) has been studied with the aim to develop microdiagnostica for the presence of low-molecular-weight compounds in native biological fluids. The problem was solved using two enzymes: lactate dehydrogenase and urease. Polyelectrolyte microcapsules were prepared using two polyanions: polystyrene sulfonate (PSS) and dextran sulfate (DS), and two polycations: polyallylamine (PAA) and polydiallylmethylammonium (PDADMA).

[An electron microscopy study of the structure of polyelectrolyte microcapsules containing protein and containing no protein].

Electron micrographs of ultrathin sections of polyelectrolyte microparticles containing protein and free from protein for the formation of which CaCO3 spherulites served as a core basis have been obtained and analyzed. Polyelectrolyte microparticles with the number of alternately layered polyelectrolyte layers of polystyrene sulfonate and polyallylamine from 6 to 11 have been studied. It follows from the data obtained that protein-free polyelectrolyte particles having the dimensions 4.

[Conformation and molecular and ionic transformations of polycytidylic acid immobilized in multilayer Langmuir and polyelectrolyte films].

Multilayer films of complexes of polycytidylic acid with dioctadecyldimetylammonium were obtained by the Langmuir-Blodgett method (LB films), and complexes of poly(C) with polycations (poly-L-lysisne, polyethyleneimine, polyallylamine) were obtained by the method of alternate adsorption (polyionic assembly) from solutions of oppositely charged polyelectrolytes on the solid carrier (SA films). It was shown that poly(C) exists in SA films in a single-stranded state irrespective of whether in the starting solution it occurred in the single-stranded nonprotonated or double-stranded protonated conformation. Conversely, in the LB film poly(C) preferred to be in a double protonated conformation.

[Lactate dehydrogenase in an interpolyelectrolyte complex. Function and stability].

A new method for encapsulating enzymes by multilayer polyelectrolyte coating is proposed. The method consists in a stepwise adsorption of polyelectrolytes from solution onto protein aggregates formed by salting out the proteins in highly concentrated salt solutions. Polystyrene sulfonate and fluorescence-labeled polyalylamine were used for capsule formation.

Multilayer films containing immobilized nucleic acids. Their structure and possibilities in biosensor applications.

Langmuir-Blodgett (LB) and film technologies based on electrostatic attraction self-assembly (SA) are shown to be useful for immobilization of nucleic acids (DNA, polynucleotides) onto solid supports in sensor devices. The nucleic acids were immobilized in complexes with cationic surfactants (for LB) and polycations (for SA). Infrared spectral studies showed that DNA unfolds in multilayer LB films with octadecylamine and conserves its double helical structure in the LB films with dioctadecyldimethylammonium and in the SA films with polyallylamine, polyethylenimine and poly-L-lysine.

[IR-spectroscopic study of the interaction of chromium salts with native DNA].

Infrared spectra of some unoriented films of DNA contained CrCl3, K2Cr2O7 and Cr2(SO4)3 have been obtained at relative humidities (r.h.) 0 to 93%.

[DNA-protein cross-links as a possible reason for genomic damage during its protonation].

The change in survival of bacteriophages with DNA of different GC-contents after their incubation in media of different acidities with subsequent neutralization was studied. It was shown that the higher the GC-content, the more sensitive is the phage to the action of H(+)-ions. Evidence is presented that the acidic inactivation of virions is not connected with the helix-coil transition of the intraphage DNA due to its protonation.

[Effect of oxygen on gamma-radiation damage to nucleic acids irradiated in media with different pH values].

The injury to DNA and RNA exposed to gamma-radiation in media of varying acidity with oxygen present or absent therein has been investigated. The interaction of the protonated base with a superoxide radical has been shown to contribute markedly to the oxygen effect of the radiation injury to nucleic acids.

[The role of protons in a medium in gamma-radiation-induced damage of nucleic acids].

The study of the combined effect of gamma-radiation and acid medium (pH 7.0-2.0) on DNA and RNA showed that the radiation-induced injury to nucleic acids increased with increasing concentration of H+-ions in the medium up to pH values below which protons exerted a protective action.

[Irreversible changes in phage DNA after its protonation in solution and inside the virion detected by the transfection method].

The dependence of irreversible structural changes in phage lambda DNA on the degree of its protonation in a solution and inside the virion has been found by measuring the transfection activity of bacteriophage. The different effect of ionic strength on pH-dependence of the irreversible changes in the structure of DNA upon its protonation in a solution or in situ has been registered and explained. The insignificant shift of pH from neutral region value in 0.

[The causes of hydration changes during DNA protonation].

Changes of DNA hydration provoked by protonation in the way of Na+- and H+-ions exchange, and in the way of HCl addition to Na+-DNA, were analysed by IR-spectroscopy. Water is shown not to contribute essentially to the formation and stabilization of conformations arising when DNA is protonated. The differences between hydratation of DNA protonated by different ways are in the main accounted for by alteration of the quantities of Na+ and Cl- ions forming the aqueous-salt envelope of polynucleotide.

[Mechanism of the radiation damage to the secondary structure of DNA].

The authors describe the mechanism of radiation-induced damage of a secondary DNA structure suggesting that a double-helical brim conformation adjacent to a local defect in the secondary structure, and the thermoactivated threshold process of a "confluence" of the defects are present in the irradiated DNA. It is supposed that the major type of the radiation damage to the spatial DNA structure is a triple helix repaired with the aid of the specific endonuclease.

[Structure and function of DNA--membrane contact in cells].

A model of DNA-membrane contact based on the postulate about the determining role of membrane RNA (mbRNA) in providing its specifitity, stability and functional activity is proposed. Proceeding from the DNA-membrane contact structure, unity and interconditionality of reduplication and transcription processes are shown, and basic peculiarities of reduplication are discussed. It follows from the analysis of lysozyme-detergent treatment that two different DNA-membrane complex preparations can be obtained: one of these upon the spheroplast - "turned inside out spheroplast" transition, the other, containing specific DNA-membrane contact only - in the course of further detergent treatment.

[Infrared spectroscopic study of DNA--lipid interactions. DNA compacting on disperse particles].

Within the range of relative humidity (r. h.) 0 to 92% there were obtained IR-spectra (4000--900 cm-1) of undeuterated and deuterated films of rat liver lipids, both in the free state and in the complex with native (nDNA) and heat-denaturated DNA (dDNA).

[Study of structural transformations of the sugar-phosphate chain and nitrogen bases of DNA hydrate by IR-spectroscopy].

The IR-spectra (900-1800 cm-1) of films of native and denatured DNA were studied within the temperature range 4-100 degrees C at different relative humidity (r.h.).