Dependence of mode of DNA binding to benzo crown derivatives of actinocin on the size and distance from the chromophore of crown fragments

Complexes of DNA with benzocrown derivatives of actinocin were studied by viscometry and dynamic birefringence. Changes in the macromolecular structure of DNA caused by complex formation were determined. Models of DNA binding to the studied compounds were suggested on the basis of data obtained. The intercalation of actinocin chromophore of benzocrown derivatives of actinocin was shown to occur only when benzocrown groups were bound to the chromophore via glycine fragment. A change in the distance between the crown group and the chromophore prevents ligand intercalation. Increase in medium ionic strength results in appearance of new nonintercalational binding mode for crown-containing compounds with DNA caused by interaction of the crown groups with DNA.     

Karyotype of blue honeysuckle species (Lonicera subset. Caeruleae,Caprifoliaceae

For the first time the karyotypes of diploid (2n = 2x = 18) and tetraploid (2n = 4x = 36) species of Lonicera from the Caeruleae subsection: L. altaica Pall., L. boczkarnikowii Plekh. (L. regeliana Boczkarn.), L. edulis Turcz. ex Freyn (2x, 4x), L. emphyllocalyx Maxim., L. iliensis Pojark., L. kamtschatica Pojark., L. pallasii Ledeb., L. stenantha Pojark., L. turczaninowii Pojark., L. villosa (2x, 4x) (Michx.) Muhl. are described. The species karyotypes from 23 natural populations have shown the considerable generic resemblance that expressed in the similar chromosome morphology and variation range of their length from 1 to 3 microns. The species with the same level of ploidy had the same karyotype formula: 2m + 6sm + 1st in diploids and 4m + 11sm + 3st in tetraploids, respectively. The amphiploid origin of the tetraploid Lonicera species has been shown. Diploid and tetraploid forms of L. edulis and L. villosa were the particular karyotypes but not the 2x and 4x races of the same species, respectively. Specific differences were revealed in the total chromosome length in the haploid set and in the number of satellites and secondary constrictions. Generic resemblance and specific peculiarities of Lonicera karyotypes indicate a common center of the blue honeysuckle origin and a common initial population of karyotypes which evolved into several phylogenetic branches of the Caeruleae subsection: the Central Asiatic--L. iliensis and L. stenantha; the Siberian--L. altaica, L. edulis, and L. pallasii; the Beringian--L. emphyllocalyx, L. kamtschatica, and L. villosa; the Manchurian--L. boczkarnikowii (L. regeliana), and L. turczaninowii.     

A new assay format for electrochemical immunosensors: polyelectrolyte-based separation on membrane carriers combined with detection of peroxidase activity by pH-sensitive field-effect transistor

A new rapid immunotechnique combining separation of reactants by filtration through a porous membrane and potentiometric detection of the bound enzyme label by a pH-sensitive field-effect transistor is proposed. The complexes to be detected are formed by the method described earlier in (Anal. Chem. 71 (1999) 3538), including a homogeneous binding of immunoreactants and a polyanion carrier (polymethacrylate) followed by heterogeneous separation on a membrane incorporating an immobilized polycation (poly-N-vinyl-4-ethylpyridinium). The proposed technique for a sensitive detection of peroxidase label is based on the measurement of pH changes in the optimised substrate solution containing o-phenylenediamine, hydrogen peroxide and ascorbic acid. The antigens studied were herbicide atrazine and hormone testosterone. Their specific detection is realised via competitive binding of free and peroxidase-labelled antigens by antibodies integrating with a (staphylococcal protein A-polyanion) conjugate. The total analysis time is 20-25 min. The range of quantitative detection is 0.2-100 ng ml(-1) for atrazine and 5-300 ng ml(-1) for testosterone. Data scatter of replicate tests varies from 3 to 10%. Application of protein A-polyanion conjugate allows to use the proposed protocol for different antigens without additional treatment of specific antisera.     

Bacterial Cellulose as a Matrix for Microorganisms in Bioelectrocatalytic Systems

Applied Biochemistry and Microbiology - Bacterial cellulose (BC) produced by the Komagateibacter sucrofermentas VKPM B-11267 bacteria was used as a carrier for immobilization of acetic acid...     

Use of infusoria Paramecium caudatum for the evaluation of the toxicity of antigens of different causative quarantine agents

The results of the evaluation of the toxicity of bacterial antigens obtained from the causative agents of plaque, glanders, melioidosis, cholera on infusoria of the species P. caudatum, as well as on cell lines L-929, CHO K-1 and peritoneal macrophages of BALB/c mice, are presented. As revealed in this study, the method of toxicity determination on infusoria is similar in its sensitivity to the methods of testing on. CHO K-1 and L-929 cells, but the former is simpler, more available and permits the determination of toxic doses producing disturbances in the vital activity of the infusoria, but not leading to their death.     

Entrapping of hydrophobized plague capsular antigen into large unilamellar liposomes

The entrapping of a plague capsular antigen into the liposomes, prepared by the "reverse phase" evaporating method, was investigated. Both the native antigen and the antigen modified by palmitoylchloride were used. The entrapping of the modified antigen into the liposomes was greater than that of the native one: 46.1 +/- 5.4% and 3.7 +/- 2.7%, respectively. The highest content of the antigen on the membrane surface was observed when using palmitoylized protein and liposomes with egg lecithin, cholesterol and dicethylphosphate in the molar ratio 7:2:1.     

Urinary enzymes induced in rats by intensive physical loading and the effect of the antioxidant potassium fenozan

The rats subjected to repeated heavy exercises (swimming with the load equal to 10% of body weight) had an increased activity of gamma-glutamyl transpeptidase in the urine. Both the percentage of the rats with hyperenzymuria and the level of enzyme were the highest after the fifth swimming. Water-soluble antioxidant (potassium fenozan) administered intraperitoneally 30 minutes before the swimming abolished the increase of enzymuria and maintained the enzyme activity to the normal level.     

Prediction of the three-dimensional structure of aflatoxin of Aspergillus flavus by homology modelling

Aflatoxins are polyketide-derived secondary metabolites produced by Aspergillus spp. The toxic effects of aflatoxins have adverse consequences for human health and agricultural economics. The aflR gene, a regulatory gene for aflatoxin biosynthesis, encodes a protein containing a zinc-finger DNA-binding motif. AFLR-Protein three-dimensional model was generated using Robetta server. The modeled AFLR-Protein was further optimization and validation using Rampage. In the simulations, we monitored the backbone atoms and the C-α-helix of the modeled protein. The low RMSD and the simulation time indicate that, as expected, the 3D structural model of AFLR-protein represents a stable folding conformation. This study paves the way for generating computer molecular models for proteins whose crystal structures are not available and which would aid in detailed molecular mechanism of inhibition of aflatoxin.