Modification of the target cell surface with lipophilic glycoconjugates and interaction of the modified cells with natural killer cells

An experimental model system involving the modification of carbohydrate composition of the target cell surface with neoglycolipids was developed for studying the role of surface carbohydrates of target cells in the NK-cell-mediated cytotoxicity. The polymeric glycoconjugates of the Glyc-PAA-PEA and Glyc-PAA(Flu)-PEA types (where Glyc was an oligosaccharide residue, PAA poly(acrylamide) polymer, and PEA the phosphatidylethanolamine residue, and Flu fluorescein residue) capable of incorporation into the cell membrane were synthesized. The optimum structures of neoglycoconjugates and conditions for their incorporation into K562 and Raji cell lines, which differ in their sensitivity to the NK-cell-mediated lysis were selected. The mechanism of association of glycoconjugates with the plasma cell membrane and the kinetics of their elimination from the cell surface were investigated using the fluorescent-labeled Glyc-PAA(Flu)-PEA derivatives. The spatial accessibility of the carbohydrate ligands for the interaction with human NK cells was demonstrated. The target cells modified with the Le(x) trisaccharide were shown to be more sensitive to the cytotoxic effect of human NK cells than the intact cells. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru.     

Vibrio cholerae 01, variant eltor,in the environment

The possibilities of the autochthonous existence of V. cholerae in open water reservoirs, depending on the combined effect of different biotic and abiotic factors are considered. The role of adaptive variability of V. cholerae O1, biovar eltor for its preservation in the environment is emphasized. The data on the duration of the V. cholerae O1 isolation from different environmental objects in some regions of Ukraine are presented.     

Artificial Tn2551 transposon with replicative properties

A hybrid plasmid, pBE10 was constructed. It consists of DNAs of RSF2124 (ColE1 :: Tn3) plasmid and pUB110 plasmid of Staphylococcus aureus. The latter can be stably maintained in Bacillus subtilis. BamHI cleaved pUB110 was introduced into the BamHI site of transposon Tn3 and the resulting enlarged Tn3 (Tn2551) was transposed from pBE10 onto phage lambda and than to pMB9 (Tc) and RSF1010(Sm Su) plasmids. Restriction and heteroduplex analysis of pMB9 :: Tn2551(pBE21) and RSF1010 :: :: TN2551(pBE32) was carried out. Plasmids pBE10, pBE21 and pBE32 demonstrated some kind of molecular instability when introduced by transformation into Bacillus subtilis.     

The CELO-ANG recombinant avian adenovirus with human angiogenine gene inducing neovascularization in the anterior tibial muscle of rat

The CELO recombinant avian adenovirus carrying the gene coding the human angiogenine (ANG) synthesis was obtained. Expression of the angiogenine gene was shown in the LMH cell culture after infection with the CELO-ANG virus. The ability of CELO recombinant adenoviruses to carry out the delivery and expression of alien genes in muscle cells was demonstrated in experiments with laboratory animals (Wistar line rats). The induced neovascularization in rat muscles after the animals were administered the CELO-ANG viruses was shown.     

Development of blunt Tilletia caries (D.C.) Tul. pathogen on embryogenic wheat callus

The development of Tilletia caries on embryogenic and morphogenic wheat calluses from germination of spores up to sorus formation have been investigated. Pathogene growth was similar in variants with wheat calluses of susceptible species Triticum aestivum and resistant species T. timopheevii, but intensity of its development of embryogenic calluses of both species was lower, than on morphogenic. Necrosis of parenchyma-like cells was more distinct in the embryogenic than in morphogenic calluses. It was combined with low accumulation rate of infected cells in embryogenic calluses. Necrosis reduced the healthy cell reproduction in meristem-like cells of morphogenic calluses and thereby additionally decreased resistance of morphogenic calluses to pathogene.     

Dependence of the kinetics of forming phases of a two-phase polymeric system on actin state

New analytical possibilities of biological macromolecule partition in a two-phase polymer system (dextran-500/polyethyleneglycol-6000) were investigated. The technical principles were based on the fact that optical density of the system changes during phase formation. Various actin forms were investigated. Unlike G-actin, F-actin increases the speed of phase formation. Different actin isoforms exert different influence on this process. The kinetics of the partition system into phases makes it possible to figure out the picture of native G-actin damage. The two-phase polymer system has been shown to be capable of supporting the native properties of actin for not less than 6 days at 20 degrees C. An assumption is made that two-phase systems can be used for imitating the intracellular medium in studies on actin functional characteristics.     

Introduction of the human recombinant angiogenin at the early stages of postnatal development inhibits the growth of mice

We studied the influence of recombinant DNA containing the cloned angiogenin gene, plasmid DNA without angiogenin gene, and purified recombinant angiogenin injected to Tg8 mice at the age of two days on the body mass of 28- and 40-day old mice. The body mass of mice that were injected with the cloned angiogenin gene or purified angiogenin was less than in the control mice. The body mice of Tg8 mice injected with recombinant DNA containing the cloned angiogenin gene did not increase from day 2 to day 40, while in the mice with purified recombinant angiogenin and control mice it increased by 24 and 57%, respectively. These data suggest that the elevated level of angiogenin at the early developmental stages inhibits the increase of body mass. The effect we described as related, in al likelihood, to the known inhibitory effect of angiogenin on protein synthesis.     

Study of reparative DNA synthesis in lymphocytes of persons occupationally exposed to radiation

The UDS efficiency in lymphocytes of professionals chronically exposed to gamma/neutron radiation, as well as for a control cohort was estimated. A credible reduction of UV-induced UDS (KUV) index as compared to the control was demonstrated. This shows an invalid repair state of blood cells in professionals. As for the control cohort, the decreasing tendency of UDS index with age was found. The correlative analysis of UDS index dependence upon an absorbed dose (based on physical dosimetry data) revealed the trend towards repair index reduction along with a higher total absorbed doze, that is followed by UDS index coming onto a plateau. It was also demonstrated that after a sharp and/or accidental irradiation UDS index reduces as compared to permanent portioned irradiation. It was not observed the influence of smoking upon UDS efficiency in blood lymphocytes neither for control, nor for experimental group. The analysis of vitamin therapy of the both cohorts showed that such therapy raises UDS index of the control (i.e., non-professional) group. Besides, it was found out an additional positive effect of vitamin therapy, i.e. doze leveling in long-term perspective after irradiation. The most expressed KUV/doze correlation was characteristic for professionals, who do not take vitamins and do not smoke. This proves that in blood cells of professionals it is preserved a dependence of repair system invalidity upon the absorbed doze without similar external factors.     

Microbiocenosis of the large intestine in acute complicated pneumonia in children

Fifty-six children of early age with pneumonia developed on the background of frequent respiratory infections were placed under observation. In 91.1% of these cases microecological disturbances in the intestine were detected, 46.6% of the patients having third-degree dysbacteriolysis. In such cases it is more correct to regard the "intestinal" syndrome as the clinical manifestation of disturbances in the biocenosis of the intestine, the state of its microflora. Intestinal dysbacteriosis aggravates the course of acute aggravated pneumonia in children and requires the inclusion of special therapy aimed at normalizing intestinal microflora.