[COMPARATIVE ANALYSIS OF TIGHT JUNCTIONS OF EPITHELIUM OF RATS JEJUNUM UNDER THE EFFECT OF LIPOPOLYSACCHARIDE AND CHOLERA TOXIN].

AIM: Comparative study of tight junctions and ultrastructure alterations of enterocytes of mucous membranes of jejunum of rats under the effect of lipopolysaccharides and cholera toxin. MATERIALS AND METHODS: Lipopolysaccharides (Sigma-Aldrich, Germany) and cholera toxin (Sigma-Aldrich, Germany) were used. The study was carried out in Wistar line rats. Effect of lipopolysaccharides and cholera toxin on epitheliocytes was carried out by a method of withdrawal of segments of rat jejunum and their incubation with the specified substances. Comparative analysis of ultrathin sections of enterocytes of jejunum of rats and tight junctions between them was carried out in control and under the effect of lipopolysaccharides and cholera toxin. RESULTS: Effect of lipopolysaccharides on ultrastructure of enterocytes of rat jejunum manifested in the change of cell form as a result of increase of intercellular space without destruction of tight junctions. Disappearance of desmosomes, increase of nuclei and more pronounced ER were noted in some epitheliocytes. Effect of cholerogen on epitheliocytes of mucous membrane of rat jejunum by a number of signs is similar to the effect of lipopolysaccharides, that manifested in an alteration of ultrastructure of cell, the form of those also transformed as a result of an increase of intercellular space, this process was not accompanied by destruction of tight junctions. Disappearance of folding of the lateral region of plasmatic membrane of cells and a reduction of a number of microvilli was observed under the effect of cholera toxin. CONCLUSION: A similar character of effect of lipopolysaccharides and cholera toxins on ultrastructure of cells and region of tight junctions of enterocytes of rat jejunum was detected, both substances caused an increase of intercellular space without the destruction of tight junctions.

[Sorption properties of various polysaccharide matrixes to Lactobacillus plantarum 8RA-3 bacteria].

AIM: Study of sorption properties of various spherical polysaccharide matrixes designated as Spherocell to probiotic Lactobacillus plantarum 8RA-3 bacteria. MATERIALS AND METHODS: Industrial strain of L. plantarum 8PA-3 was used. The process of immobilization of lactobacilli on 3 variants of spherical sorbents was studied. The first sorbent - neutral, composed of nonpolar cellulose matrix with ("0") charge, the second--DEAE obtained by modification of cellulose by diethylaminoethyl groups with positive ("+") charge and the third--CM (carboxymethyl) with negative ("-") charge. Cellulose matrixes were designated by us by the term Spherocell. Immobilization of bacterial cells on Spherocell was performed by addition of suspension containing 1.0 x 10(9) CFU/ml. The effect of bacterial immobilization was evaluated by CFU/ ml titration and by electron microscopy. RESULTS: The dependence on matrix charge of adsorption immobilization on sorbent granules of lactobacilli cells was shown. At certain equal parameters (granule size, surface characteristics, charge value) the positively charged matrix sorbed 3-10 times more cells than neutral and 20-25 times more than negatively charged matrix. Each 100-180 microm Spherocell DEAE particle could sorb more than 1000 viable bacterial cells. CONCLUSION: Positively charged polysaccharide matrix Spherocell DEAE obtained by modification of cellulose by diethylaminoethyl groups is promising for creation of immobilized probiotic preparations.

[Disorganization of biofilms of clinical strains of staphylococci by metabolites of lactobacilli].

AIM: To study morpho-physiologic characteristics of clinical biofilm-forming strains of Staphylococcus aureus and S. epidermidis suppressed by metabolites of lactobacilli, which produce bacteriocin-like substances. MATERIALS AND METHODS: Two clinical biofilm-forming strains of S. aureus and one strain of S. epidermidis were used. Strains Lactobacillus plantarum L3 and L. fermentum 97 were used as producers of bactericidal metabolites. Ability of staphylococci to form biofilms was studied after their growth during 18 h at 37 degrees C in beef-extract broth with subsequent registration of biofilms attached to walls and bottom of polystyrene plate and stained by 0.1% alcohol solution of crystal violet. Ultrastructural changes in target cells were visualized by electron microscopy. RESULTS: Suppressive effect of lactobacilli metabolites on formation of biofilms by staphylococci was established. Ultrasructural changes, which characterize disorganization of vital processes such as mitosis, synthesis of DNA and peptidoglycan layer, were revealed in target cells. Formation and detachment of peptidoglycan globules from cell wall surface externally were noted. CONCLUSION: Metabolites of lactobacilli are able to suppress formation of biofilms and induce ultrastructural changes in S. aureus and S. epidermidis, which lead to their destruction.