Interaction between plasma lipoproteins and bilayer lipid membranes. The role of surface charge

Interactions of planar BLM with different thickness and surface charge were analysed theoretically. Drawing together of the membranes is accompanied with the appearance of intramembrane potential jumps which may cause destruction and breakdown of the membranes. The theory is extrapolated to the interaction between spherical lipoprotein particles and planar BLM. Experimentally calculated (by means of ESR) surface charges of lipoproteins of low density (LLD) (--0,3 . 10(-2) C/m2) and lipoproteins of high density (LHD) (--2 . 10(-2) C/m2) enabled calculation of the interaction energy between the particles and BLM as well as of the values of intramembrane potential jumps. The latter cause local reconstructions of the membranes in the contact region and fusion of the particles with them. The earlier obtained experimental data were proved by the finding that LHD adsorption as compared with LLD is impeded due to the existence of a high energetic barrier. These peculiarities of the particles manifested during their interactions with BLM seem to be one of the factors responsible for atherogenic function of LLD and antiatherogenic one of LHD.     

Culture performance of different strains and crosses of the European sea bass (Dicentrarchus labrax) reared under controlled conditions at Eilat, Israel

The European sea bass (Dicentrarchus labrax) is one of the most important commercial marine fish species in the Mediterranean basin. However, broodstock domestication and selective breeding on a production scale have yet to be exploited. We reared progeny of sea bass from three different strains and their crosses throughout the entire growth cycle to market size. Data sets were analyzed to assess whether culture performance differs among different strains and crosses reared under controlled laboratory conditions using both separate and communal rearing techniques. Strains and crosses of sea bass varied significantly for traits of economic interest such as growth, survival, body composition, sex ratio, sexual maturation patterns of males, and frequencies of body shape abnormalities. Lack of evidence for substantial heterosis for growth among reciprocal crosses was also detected. Significant sexual dimorphism for length and weight was evident in all strains and crosses. At market size, the resulting weight advantages of females varied between strains and crosses; overall average weight advantage for females was about 39%. Length and weight of individual fish were strongly correlated during different time intervals. This may be useful for the choice of selection criteria, raising the possibility that the response to selection for weight at market time may be achieved by conducting selection on young fish. Generally, the results showed a high culture potential of sea bass strains originating from the southeastern areas of the Mediterranean Sea, suggesting that these domesticated strains can be exploited in future selective breeding programs.     

Studies of lipopolysaccharides from Yersinia pseudotuberculosis subtypes VA and VB

Lipopolysaccharides (LPS) from various strains of Yersinia pseudotuberculosis type V have been isolated and characterised. Differences in sugar composition and serological activity of LPS from various strains within the same subtype of Y. pseudotuberculosis have been revealed.     

Vanadyl Causes Hydroxyl Radical Mediated Degradation of Deoxyribose

Vanadyl caused a time- and dose-dependent degradation of deoxyribose to carbonyl products detectable with thiobarbituric acid. This process was inhibited by catalase, ethanol or HEPES; whereas superoxide dismutase was without effect. Vanadate did not substitute for vanadyl even in the presence of a source of O₂^- plus H₂ O ₂; but it did so in the presence of reductants such as thiols or NADH. It appears that hydrogen peroxide, generated by the autoxidation of vanadyl, is reduced by vanadyl to the hydroxyl radical; which, in turn, was responsible for the degradation of deoxyribose. A similar process might contribute to the toxic and pharmacological effects of vanadium salts.     

Chromosome polymorphism in populations of the grasshopper Trimerotropis pallidipennis from southern Argentina

Three populations of the grasshopper Trimerotropis pallidipennis from southern Argentina have been studied cytologically. A very characteristic B-chromosome was found in all three. They also showed geographical variability in respect of the presence of pericentric inversions, and the inversion system was found to influence chiasma frequency. The Laguna Blanca population, which is on the hypothetical pathway the species is believed to have followed during its migration from northern to southern latitudes, has the same karyotype composition as the N. American form, with fixed inversions in the 3 largest autosomes and the X-chromosome. Its members have a high total chiasma frequency and a great number of interstitial chiasmata. The Sierra de la Ventana population, situated at the absolute eastern border of the species distribution is highly polymorphic with respect to the presence of inversions in the medium chromosomes. Its members have the lowest total chiasma frequency and a greatly reduced number of interstitial chiasmata. Situated geographically between the other two, the Choele-Choel population has the highest frequency of inversions and many of them are homozygous. Its members have a higher total chiasma frequency than that observed in specimens from Sierra de la Ventana, and a greatly reduced number of interstitial chiasmata, similar to that observed in individuals from the latter population.     

Protoplast fragmentation as one of the possible mechanisms of L-transformation of bacteria (Clostridium perfringens)]

As revealed, the action of lysozyme on the cells of Clostridium perfringens BP-6K led to the formation of not only typical spheroplasts, but also of cells whose peripheral parts of the cytoplasm were fragmented by membrane component. Small bodies framed by the membrane proper and containing granular and fibrillar components were formed. They were polymorphic in osmium treatment, and had smooth contours in preliminary use of aldehyde fixation. In the latter case a dense lumpy material analogous to the one which fills the periplasmic zone and serves as a rigid wall component formed at the surface of the protoplasm and bodies-fragments. In case of escape of the bodies into the external environment through the perforations in the cell wall the principal mass of the protoplast remains intact. The morphology of the bodies-fragments indicated a principal possibility of their autonomic existence. It is supposed that the phenomenon described could serve as one of the mechanisms of L-cell formation.     

The Influence of Effectors of the Ca2+ Signaling System and Oligosaccharin OSRG on IAA-Induced Formation of Adventitious Roots on Explants of Buckwheat Hypocotyls

Russian Journal of Plant Physiology - The interplay between different signaling pathways that occurs during the development of a root system is investigated by considering, by way of example, the...     

Three-Domain Antibodies against the Tumor Necrosis Factor: Investigation of Their Biological Activity In Vitro

Russian Journal of Bioorganic Chemistry - The aim of this work was to evaluate novel three-domain antibodies consisting of two domains specific for human tumor necrosis factor (hTNF), and of the...     

The investigation of structure–activity relationship of polyamine-targeted synthetic compounds from different chemical groups

Amino Acids - The polyamine (PA) metabolism is involved in cell proliferation and differentiation. Increased cellular PA levels are observed in different types of cancers. Products of PA oxidation...