Expression of aryl hydrocarbon receptor and ATG16L1 protein in experimental oxazolone-induced colitis in rats.

We studied the expression of AhR and ATG16L1 protein in experimental oxazolone-induced colitis in rats and anti-inflammatory action of recombinant antagonist of IL-1 receptors (ARIL-1) and simvastatin. The immunopositive cells were determined using an indirect immunofluorescence technique with using a monoclonal rat antibody. It has been established that development of colitis was accompanied by an increase of total number of ATG16L1-lymphocytes (by 30%, P < 0.05) in lymphoid structures of the colon. However the amount of AhR(+)-lymphocytes has not changed. At the same time has increased the concentration of ATG16L1 protein (by 4-11%, P < 0.05) in immunopositive cells. Administration of simvastatin and ARIL-1 during the development of experimental pathology was accompanied by decrease of total number of AhR(+) (by 24-38%, P < 0.05) and ATG16L1(+)-lymphocytes (by 43% - 2 fold, P < 0.05) in the colon.

Expression of XBP1 in lymphocytes of the small intestine in rats under chronic social stress and modulation of intestinal microflora composition.

The present study was conducted to investigate of the influence of chronic social stress and modulation of the composition of intestinal microflora on the distribution of Xbp(1+)-lymphocytes in the gut-associated lymphoid tissue of ileum of the rats. Structure of population of Xbp(1+)-cells has been studied by the analysis of serial histological sections using the method of indirect immunofluorescence with monoclonal antibodies to Xbp1 of rat. Chronic social stress development is accompanied with the reduction of total number of Xbp(1+)-lymphocytes in lymphoid structures of ileum (31% -3 fold reduction, p < 0.05), mostly expressed in lymphoidfollicles, and changes the concentration of Xbp1 protein in immunopositive cells. Modulation of the composition of intestinal microflora by antibiotics and probiotics under chronic social stress results in the increase of total number of Xbp1+ lymphocytes in gut-associated lymphoid tissue, the degree of it depends on the kind ofstress. The discovered alterations of Xbp1 expression under stress may be one of the triggers for development of autoimmune and inflammatory bowel diseases. Thus, increased understanding of the molecular actions and transcriptional networks regulated by XBP1 in immune cells may aid in the development of potential therapeutics targeting immune disorders.

VO2/Si-Al gel nanocomposite thermochromic smart foils: largely enhanced luminous transmittance and solar modulation.

VO2 nanoparticles with a dimension of approximately 20 nm were obtained by simple mechanical bead-milling method, which were well dispersed in transparent silica-alumina (Si-Al) gel matrix to form nanocomposites. The VO2/Si-Al gel thermochromic nanocomposite foils were fabricated with various VO2 solid contents and foil thickness. With 10% VO2 loading and 3 µm foil thickness, high luminous transmittance (T(lum(20°C))=63.7% and T(lum(90°C))=54.4%), and large solar modulation ability (ΔTsol=12%) can be obtained which surpasses the best reported results (nanoporous films:T(lum(20°C))=43.3%, T(lum(90°C))=39.9% and ΔTsol=14.1%). This current approach provided a simple and scalable preparation method with the best combined thermochromic performance.

Study of expression of TLR2, TLR4 and transckription factor NF-kB structures of galt of rats in the conditions of the chronic social stress and modulation of structure of intestinal microflora.

The present study was conducted to investigate of the influence of chronic social stress (CSS) and modulation of the composition of intestinal microflora on the distribution of TLR2+-, TLR4+- and Nf-kB+-cells in the GALT of ileum of the rats. Researchers have been conducted on 84 rats (female) of Wistar line, which were divided on 7 experimental groups: control rats (group 1); rats, which were modeled CSS1 by means of three weeks social isolation and prolong psychoemotional influence (group2); rats, which having CSS 2 modeling by means of keeping animals in over populated cages with every day change of grouping (group 3); rats with CSS1 and CSS2, which were made the modeling of intestinal microflora by means of administrations of aminoglycosed antibiotic kanamycin (group 4 and 5, accordingly); rats with CSS1 and CSS2, which were made the modeling of intestinal microflora by means of everyday administrations of lactobacterine (groups 6 and 7, accordingly). Structure of population of TLR2+-, TLR4+- and Nf-kB+-cells has been studied by the analysis of serial histological sections using the method of direct and indirect immunofluorescense with monoclonal antibodies to TLR2, TLR4 and Nf-kB. CSS development is accompanied with increase in total lymphocytes expressing TLR2 and 4 type GALT rats with the most pronounced in LFV (TLR2+-lymphocytes) and PP LFs (TLR4+-cells) led to an increase in the number of Nf-kB+- cells: in LFV a 1.8-2 fold (p<0.05) in PP at the sub - 52-91% (p<0.05) in PP LFs - for 89-92% (p<0.05), and it is also influenced on the density of TLR2, TLR4, and the concentration of Nf-kB in immunopositive cells. AB and PB injections were accompanied by a decrease in the number of studied cells, so in the separate zone GALT is increased to their number, changing the density of immune system receptors.

Regulation of acid phosphatase in reverse micellar system by lipids additives: structural aspects.

Reverse micelles system is suggested as a direct tool to study the influence of membrane matrix composition on the activity and structure of membrane-associated enzymes with the use of acid phosphatase (AP) as an example. In reverse micelles the functioning of the monomeric and dimeric forms of AP could be separately observed by variation of the size of the micelles. We found that including the lipids into the micellar system can dramatically affect the enzyme functioning even at low lipid content (2% w/w), and this effect depends on the lipid nature. Structural studies using CD spectroscopy and DLS methods have shown that the influence of lipid composition on the enzyme properties might be caused by the interaction of lipids with the enzyme as well as by the influence of lipids on structure and properties of the micellar matrix.

Inorganic polysulfides' quantitation by methyl iodide derivatization: dimethylpolysulfide formation potential.

Inorganic polysulfides are important intermediates in the formation of dimethylpolysulfides and possibly other volatile sulfur compounds of environmental significance. Currently, direct determination of these ions in the concentration range of natural systems is practically impossible, particularly under oxic conditions. Polysulfide quantification by derivatization with methyl iodide or d6-methyl iodide is emerging as a valuable alternative method for studies of polysulfide formation in natural systems. This manuscript presents detailed studies aimed at the evaluation of this method. We determined the conversion of the inorganic polysulfides to dimethylpolysulfides by methylation with methyl iodide. Close to 100 per cent of the molar concentration of polysulfide salts were converted to organic polysulfides for very low concentrations of dissolved polysulfide solutions, but only a small recovery was obtained for high concentrations of polysulfide precursors or when the solubility limit was exceeded. The recovery of polysulfides based on the calculated dissolved polysulfide concentration exceeds 1,000 per cent for very low dissolved concentrations of polysulfides. This unexpected dependence is attributed to continuous inorganic polysulfide formation from hydrogen sulfide and sulfur precipitate concurrent with, and in fact driven by, the methylation process.

Formation of carbonyl sulfide by the reaction of carbon monoxide and inorganic polysulfides.

OCS formation by the reaction of inorganic polysulfides with carbon monoxide, which are both abundant in natural aquatic systems, was studied as a model abiotic route for OCS formation in the dark. The net OCS accumulation rate was a function of a bimolecular formation reaction and simultaneous OCS hydrolysis kinetics. The reaction of polysulfides with CO in the dark was found to be first order with respect to CO concentration and first order with respect to the molar sum of the polysulfide species generated by the disproportionation of the dissolved polysulfide precursors. The pH dependence of the OCS production rate was controlled by the pH-dependent disproportionation of polysulfide precursors. Lower temperatures, intermediate redox potentials, and moderately basic pH conditions increase the steady-state concentration of OCS. The speciation of polysulfides in aqueous solutions is still disputed. Some authors claim that hexasulfide is one of the dominant species while others believe that pentasulfide is the largest sulfide species in aqueous systems. Despite the disagreement between different models for speciation of polysulfides, the proposed rate law agreed very well with the thermodynamic data based on four and on five polysulfide species, with only minor differences in the preexponential kinetic coefficients.

Native and Hydrophobically Modified Human Immunoglobulin G at the Air/Water Interface.

The adsorption of human immunoglobulin G (IgG) at the air/water interface was monitored both by the in situ radiotracer technique using [(14)C] labeled IgG and by surface tension measurements. The results reveal that adsorption of IgG from single protein systems displays bimodality due to molecular rearrangements at the interface. Above the threshold value of 1.5x10(-2) mg/ml solution concentration, adsorbed IgG molecules reoriented from the side-on to the end-on configuration. The existence of a lag time which did not appear in Gamma=f(t) curves, was observed in Pi=f(t) relationships at low protein concentrations and was due to the limits of the surface pressure technique to detect protein adsorption. The adsorption of native IgG was also carried out in the presence of a hydrophobized IgG obtained by grafting capryloyl residues to its lysine groups by reaction with N-hydroxysuccinimide ester of caprylic acid, which yielded 19 covalently bound alkyl chains to the IgG molecule (19C(8)-IgG). This modified IgG exhibited enhanced adsorption at the air/water interface, as manifested by its increased adsorption efficiency relative to the native protein. Sequential and competitive adsorption experiments from binary mixtures of native IgG and 19C(8)-IgG clearly demonstrate that the displacement of the native protein from the air/water interface strongly depended on the manner of how 19C(8)-IgG and native IgG competed with each other. When the two proteins competed simultaneously, 19C(8)-IgG predominantly occupied the available area but when native IgG was adsorbed first, for 2 h, the sequentially adsorbed 19C(8)-IgG was incapable of substantially displacing it from the interface. Copyright 2001 Academic Press.

Chemically Modified Glucose Oxidase with Enhanced Hydrophobicity: Adsorption at Polystyrene, Silica, and Silica Coated by Lipid Monolayers.

Covalent modification of glucose oxidase from Aspergillus niger by the palmitic acid ester of N-hydroxysuccinimide at a molar ratio ester:protein of 56:1 results in the formation of the enzyme derivative with 11 attached palmitic chains. Surface hydrophobicity measurements by a fluorescent probe, 8-anilino-1-naphthalenesulfonate, indicate a drastic increase in the hydrophobicity index of glucose oxidase after such a modification. The modified glucose oxidase displays a much higher adsorption affinity for hydrophilic (silica) as well as for hydrophobic (silica coated by phosphatidyl choline and cholesterol monolayers and polystyrene latex beads) surfaces, and forms more compact surface layers compared to the native glucose oxidase. Such a difference results from a spontaneous formation of micelle-like aggregates (clusters) of the hydrophobized enzyme molecules (average size 500 nm), which come into contact with a surface. A possible structure of the glucose oxidase surface layers and the nature of the forces determining the adsorption of the enzyme on various adsorbents are discussed. Copyright 1999 Academic Press.

Chemically Modified Human Immunoglobulin G: Hydrophobicity and Surface Activity at Air/Solution Interface.

Covalent modification of human IgG by fatty acid esters (C8 and C16) of N-hydroxysuccinimide was carried out. Surface hydrophobicity measurements, using the fluorescent probe 8-anilino-1-naphthalenesulfonate, indicate an increase in the surface protein hydrophobicity with an increase in the number and in the length of the attached alkyl chains. The modified IgGs decrease surface tension at the air/solution interface more effectively than the native protein. The values of the molecular cross-sectional areas (DeltaA) estimated from the kinetic data are in the range of 100-300 Å2 and reflect the size of protein segments at the interface during the adsorption process. About 40-50% increase in the DeltaA was observed upon attachment of the C8 groups to the native IgG. The lengthening of the bound alkyl chain from C8 to C16 results in a further increase in this value. The influence of the overall IgG hydrophobicity and the length of the attached alkyl chain on the dimensions of the mobile protein segment at the surface are discussed. Copyright 1999 Academic Press.

Penetration of Glucose Oxidase and of the Hydrophobically Modified Enzyme into Phospholipid and Cholesterol Monolayers.

The penetrant ability of the native glucose oxidase, GOx, and of the hydrophobically modified enzyme GO(mod) realized by grafting to its lysine residues alkyl C16 chains, into phosphatidylcholine dibehenoyl (DBPC), phosphatidylcholine dipalmitoyl (DPPC), phosphatidyl-ethanolamine dipalmitoyl (DPPE), phosphatidyl-serine dipalmitoyl (DPPS), and cholesterol (CHOL) monolayers was assessed by surface pressure measurements at constant area by enzyme injection to the aqueous phase beneath spread monolayers. As revealed by the magnitude of surface pressure increments (DeltaPi), both the quantities and the rates of penetration of the enzymes into these monolayers were lipid chemical nature and enzyme concentration dependent. When compared with GOx, GO(mod) displayed an enhanced penetrant ability into all the studied monolayers that resulted in rapidly attained DeltaPi plateau values, characteristic of stable systems. The influence of lipid hydrocarbon chain length and of the polar headgroup charge on the efficiency and effectiveness of GOx and GO(mod) penetration into these monolayers is discussed. Copyright 1999 Academic Press.

Adsorption of Hydrophobized Glucose Oxidase at Solution/Air Interface

The modification of glucose oxidase by palmitic acid ester of N -hydroxysuccinimide leads to the formation of a new hydrophobized enzyme with five covalently bound C16 groups. Such a modification was shown not to alter noticeably the native structure of the enzyme. The modified glucose oxidase displays enhanced surface activity at the water/air interface in comparison with the native enzyme. The maximum reduction of surface tension at all concentrations studied was higher for the modified glucose oxidase than for the native one. The modified enzyme also displayed a much steeper rise of the surface potential with time and a much more rapid attainment of the saturation plateau than the unmodified enzyme.