Phenotypic and genotypic identification of bacteria from the Burkholderia cepacia complex

AIM: Evaluation of the diagnostic value of pheno- and genotypic characteristics of B. cepacia strains collection. MATERIALS AND METHODS: Phenotypic and genetic methods of identification and differentiation of 25 strains of the B. cepacia complex. RESULTS: Polyphasic taxonomic approach utilizing multiple diagnostic tests was used for accurate identification of Burkholderia species. Algorithm for identification of microorganisms from the B. cepacia complex was developed. CONCLUSION: Combined use of phenotypic and molecular genetic tests, such as recA gene PCR, is recommended for differentiation of the B. cepacia complex genomovars.     

Efficacy of enterocin S760 in treatment of mice with anthrax infection due to Bacillus anthracis M-71

The therapeutic efficacy of enterocin S760, a broad spectrum antimicrobial peptide produced by Enterococcus faecium LWP760 was tested on mice infected with Bacillus anthracis M-71 to induce anthrax (second Tsenkovsky's vaccine). Intraperitoneal four-, two- or one-fold administration of the peptide in a dose of 25 mg/kg for 10 days for prophylactic (1 hour after the contamination) and therapeutic (24 hours after the contamination) purposes prevented or cured the infection in 90-100% of the mice versus the 100-percent lethality in the control (untreated animals). The antimicrobial activity of enterocin S760 against B. anthracis M-71 in vivo correlated with activity in vitro. Enterocin S760 is considered a novel promising antimicrobial for the treatment of grampositive and gramnegative infections.     

Properties of the isolated Bacillus subtilis strains and their influence on the intestinal microflora of experimental mice

The cultural, physiologo-biochemical adhesive and antagonistic properties of B. subtilis strains with good prospects for use as biotherapeutic preparations were studied. For further studies B. subtilis strain No. 1719 was chosen. In experiments on non-inbred white mice the animals were treated by the preparation Cifran used for their selective decontamination from opportunistic microflora and for the creation of the state of dysbiosis. The influence of the spore-forming microbe on the parietal microflora of the large intestine of the animals was shown. Reliable data on the changes in the number of microorganisms (CFU/ml) per 1 cm of the surface of the large intestine were established. As markers making it possible to evaluate the action of biotherapeutic and other medicinal remedies, easily determinable ratios of lac+/lac- of bacteria and Staphylococcus aureus/Staphylococcus spp. was proposed.     

Increase of the heart arrhythmogenic resistance and decrease of the myocardial necrosis zone during activation of cannabinoid receptors

We have found that intravenous administration of cannabinoid receptor (CB) agonist HU-210 (0.05 mg/kg), increases cardiac resistance against arrhythmogenic effect of epinephrine, aconitine, coronary artery occlusion and reperfusion in rats. Pretreatment with CB2-receptor antagonist, SR144528 (1 mg/kg), completely abolished the antiarrhythmic effect of HU-210. However this effect of HU-210 was not attenuated by pretreatment with CB1-receptor antagonist, SR141716A (3 mg/kg). We also found that HU-210 (0.05 mg/kg) decreased the relationship between infarction size and area of ischemia. It is concluded that CB2 receptor stimulation promotes an increase in the cardiac resistance against arrhythmogenic influences and probably increases myocardial tolerance of both ischemic and reperfusion damages in rats.     

Modeling heterochromatin regions in transgenic mice

Transgenic mice carrying bovine satellite DNA IV were obtained. The size of the transgene integrated into the mouse genome was approximately 390 kb (about 100 transgene copies) as determined by a semiquantitative PCR. Restriction analysis with isoschizomeric restrictases HpaII and MspI, showed that the alien DNA was methylated. In the genome of a transgenic founder male, two integration sites for satellite DNA IV were revealed by in situ hybridization and in situ PCR. These sites are situated on two different chromosomes: in pericentromeric heterochromatin and within a chromosomal arm. In transgenic mice, de novo formation of heterochromatin regions (C-block and the CMA3 disk within the centromeric heterochromatin of another chromosome) was revealed by C-banding and staining with chromomycin A3. This formation is not characteristic of mice, because their chromosomes normally contain no interstitial C-blocks or sequences intensely stained by chromomycin A3.     

Phospholipid and cholesterol levels in the tumor cell plasma membranes with different sensitivity to doxorubicin

The investigation is aimed to study qualitative and quantitative composition of phospholipids, cholesterol content and lipids unsaturation index in plasma membranes of Guerin's carcinoma cells sensitive or resistant to doxorubicin. The comparison of infrared spectra and phospholipids unsaturation index showed that the unsaturation level of fatty acids in plasma membrane from resistant cells was lower than that from sensitive carcinoma cells. 31P-NMR spectroscopy of plasma membranes phospholipids shows the increase of phosphatidylserine and sphingomyeline content in plasma membrane isolated from resistant tumor as compared with sensitive tumor. The levels of phosphatidylcholine and phosphatidylethanolamine were equal in drug-resistant and drug-sensitive carcinoma strains. Changes in plasma membrane from resistant cells result in elevation of plasma membrane microviscosity and phosphatidylserine level increase can suggest the activation of P-glycoprotein-mediated efflux of doxorubicin.     

Thermodynamic parameters of free oxidation pathways in liver mitochondria

Two pathways of free oxidation in liver mitochondria were examined. One of these pathways is determined by the protonophoric action of free fatty acids, and the other pathway, by passive proton leakage in the absence of fatty acids. According to the model of the proton futile cycle of mitochondria, the protonophoric activity of fatty acids was defined as a quotient of the division of the acceleration of respiration by fatty acid by the coefficient of respiration control for the proton leakage. The temperature dependence of the palmitate protonophoric activity on the Arrhenius plot has a break at 22 degrees C and is characterized by the transition of activation energy from 120 to 60 kJ/mol. The dependence of the respiration rate in state 4 on the Arrhenius plot is linear and, the activation energy is 17 kJ/mol. It was concluded that the first pathway of free oxidation is determined by the cyclic transport of fatty acids with the participation of metabolic carriers, and this process depends on the membrane fluidity; the second pathway is determined by passive leakage of protons through membrane channels, without fatty acids and this process is independent on membrane fluidity.     

Influence of natural complex compounds with hipolipidemic activity on expression of bacteria virulence factors

Natural complex compounds with hipolipidemic activity, having considerable inhibitory effect on expression of bacteria virulence factors were isolated. Inhibitory properties of the compounds with respect to pyocyanine and protease formation, as well as their influence on the quorum sensing mechanism in Chromobacterium violacium were shown.