Method of clonal micropropagation of different willow species and hybrids

Conditions of cultivation and micropropagation of selected biotypes of five willow species (Salyx dasyclados Wimm., S. caspica Pall., S. triandra L., S. purpurea L., and S. viminalis L.) and two hybrids (×S. acuminata S. and ×S. palustris Host.) were optimized. Data on in vitro propagation of S. caspica, S. triandra, S. purpurea together with hybrids S. acuminata and S. palustris were obtained for the first time. It has been demonstrated that the outcome of cultivation and propagation of willows strongly depends on genotypic peculiarities of initial plants. The optimal terms of isolation and sterilization of single-node segments for obtaining 50–75% of aseptic viable developing cultures were estimated. The nutritive media were selected providing induction of stem development (to 67%), their rooting (to 91%), elongation (to 3–6 cm), and multiplication (propagation coefficient of 4). The designed method (adopted to different genotypes) can be applied for obtaining aseptic in vitro cultures serving as initial plant material for genetic transformation and mass propagation of plants with new agriculturally valuable characteristics which are of interest for construction of bioenergetic plantations and for needs of the paper industry.     

The strengthening role of <Emphasis Type="Italic">D</Emphasis>:<Emphasis Type="Italic">D</Emphasis> interactions in fibrin self-assembly under oxidation

The effect on ozone-induced oxidation on the self-assembly of fibrin in the presence of fibrin-stabilizing factor FXIIIa of soluble cross-linked fibrin oligomers was studied in a medium containing moderate urea concentrations. It is established that fibrin oligomers were formed by the protofibrils cross-linked through γ-γ dimers and the fibrils additionally cross-linked by through α-polymers. The oxidation promoted both the accumulation of greater amounts of γ-γ dimers and the formation of protofibrils, fibrils, and their dissociation products emerging with increasing urea concentrations, which have a high molecular weight. It is concluded that the oxidation enhances the axial interactions between D-regions of fibrin molecules.     

Detection of biologically active substances with antagonistic and stimulating activity in Spirulina platensis

The results of studies on the detection of biologically active substances (BAS) in biomass dilutions and culture fluid of Spirulina platensi and algae (Chlorella, Fucus, Laminaria) by the agar diffusion method are presented. After the sterilization of the solutions with chloroform (CF) a substance with lysozyme-like activity and 2 substances with antagonistic activity deep in agar and on its surface were detected with the use of the micrococcal indicator strain. After CF treatment, depending on the concentration of S. platensis strains, a compound stimulating the growth of bacteria and sensitive to heat treatment was detected. BAS were also detected with the use of other indicator cultures.     

Temporal connections in the performance by children of choice-by-model reactions

Mechanisms of choice reactions by model were studied in children 3-6 years old, when the relevant figure coincided with the model by the meaning of only one of three properties, and irrelevant one--by meanings of two noncriterial properties, and differed from the model by the meaning of the criterial property. Criterial properties in various series were colour, form and size. Two propositions are substantiated: 1) the reaction presents a fine differentiation, the signal of which is the coincidence of excitations only in one of several channels of processing of information on objects physical properties; 2) alongside with positive temporary connection to excitations coincidence, in the given conditions a second inhibitory temporary connection is formed which leads to refusal from the irrelevant figure choice. Its signal is noncoincidence of excitations in the criterial channel of processing of information on objects physical properties. This second inhibitory connection is weak in 3-4 years old children and becomes stronger with age. A conclusion is made about acceptability and sufficiency of principles of temporary connection and systematization for physiological analysis of intellectual behavioural acts.     

Life cycle of tetrodotoxin-producing <Emphasis Type="Italic">Bacillus</Emphasis> sp. on solid and liquid medium: Light and electron microscopy studies

The lifecycle of the Bacillus sp. 1839 cultivated during a long period on solid and liquid Youschimizu-Kimura medium was investigated, and then bacteria and spores were studied by light and transmission electron microscopy. Sporulation in this strain is distinguished by engulfment of forespore by mother cell. In the liquid medium, bacteria have the decondensed nucleoid and the loose granular component of cytoplasm; bacteria and spores are generally smaller; the outer coat of spores includes 2 concentric rings. On the solid substratum, the nucleoid is condensed, and the cytoplasmic region is extensive and dense; a longer cultivation stimulates transition of vegetative cells into the spore form; spores have a thicker outer coat with 3–5 rings. On the solid substratum, sporulation in Bacillus sp. 1839 is spontaneous, without additional stimulation; spores have a larger diameter and thicker layers than those in the liquid medium. This research contributes to the current understanding of biotechnological tetrodotoxin production from a bacterial raw material.     

Intensification of extraction by yeast Saccharamyces cerevisiae 1968 of copper ions from a solution in magnetic field

It was determined whether it is possible to intensify the biosorption of copper ions from a copper sulfate solution with yeast Saccharomyces cerevisiae 1968 by introducing a metal headpiece into the solution and by applying an external magnetic field. The study was carried out in a magnetic field oriented both parallel and perpendicular to the axes of the rods (with parallel and perpendicular geometry of the system) that make up the headpiece. It was shown that the extent of intensification of the extraction of copper ions at different geometries of the system differs insignificantly and that the extraction of copper ions from the solution occurs by biosorption and cementation onto the metal headpiece.     

Biotechnological conditions of the synthesis of bacteriocins

In this review information on the cultivation of bacteriocin-producing microorganisms belonging to different taxonomic groups are presented. The data on the influence of the most important biotechnological parameters (nutrient medium, temperature, pH, phase of growth, etc.) on the synthesis of bacteriocins are given.     

Molecular basis of bacteriocins production and activity

Bacteriocins--bacterial proteins or peptides--are envisaged as candidates for the next generation of effective antimicrobials. Analysis of characteristics of natural and genetically engineered bacteriocins with regard to the molecular basis of their production and activity has been performed. Most bacteriocins have narrow spectrum of the inhibitory activity. Some of the broad-spectrum bacteriocins have circular molecular structure (C- and N-terminals of the aminoacid chain are joined by a peptide sequence). Fixed position of molecules' ends possibly accounts for the ability of the proteins to bind with various receptors on the surface of the target cells. Genes encoding bacteriocins and functionally associated proteins can be expressed in heterologous cells including eukaryotic cells. Also there were reports of changing bacteriocin characteristics by the use of site-specific mutagenesis.     

Study of Human Fibrinogen Oxidative Modification using Differential Scanning Calorimetry

For the first time, with the aid of differential scanning calorimetry, the thermal denaturation of fibrinogen under induced oxidation was studied. All fibrinogen structural elements detected by DSC (D region, αC-domain, and E region) are subjected to oxidation. Structural changes in fibrinogen molecule were characterized by the denaturation temperature, denaturation enthalpy, and van’t Hoff enthalpy.     

Rapid production of tetrodotoxin-like compounds during sporulation in a marine isolate <Emphasis Type="Italic">Bacillus</Emphasis> sp. 1839

The marine Bacillus sp. strain 1839 produces tetrodotoxin-like (TTX-like) compounds during sporulation. In this study, the environmental signals that regulate spore formation and the synthesis of TTX-like substances were examined. The main sporulation trigger for Bacillus sp. 1839 was changes in environmental osmolality. Confocal laser scanning (CLSM) and transmission electron microscopy with anti-TTX anti-bodies were used to locate TTX-like compounds in a sporulated culture of Bacillus sp. 1839. Based on CLSM studies, the toxin was synthesized within a few minutes after the induction of sporulation, and the fluorescence signal reached the maximum intensity in 60 min. Immunoelectron microscopy enabled the detection of TTX-positive structures in spores with unformed cores. The results obtained in this study provide an important basis for the development of biotechnological production methods for the highly effective anesthetic drug.