Characteristics of pectic polysaccharides from leek obtained through consecutive extraction with various reaction agents

Five polysaccharide fractions of commensurable by yield, but different in composition were obtained through consecutive extraction with water, solutions of ammonium oxalate, sodium carbonate, hydrochloric acid and sodium hydroxide from the alcohol-insoluble residue (AIR) of leek. In the polyuronide part of these fractions besides galacturonic acid was found also glucuronic acid. In the neutral sugar fraction, the prevailing sugar was galactose, followed by rhamnose. The water-extractable pectic polysaccharide was highly homogenous (93.3% of it had molecular mass of 1.3×10 6 kDa) and protein content of 8% (the highest compared to the other extracted polysaccharides). Extraction with diluted hydrochloric acid yielded polysaccharide with the highest neutral sugar content of 71.1% and a low uronic acids content. The water-and chelate-extractable fractions had a lower L-rhamnose content (2.7% and 2.9%, respectively) and the other polysaccharide fractions from leek were characterized by a high L-rhamnose content (from 14 to 28%). The pectic polysaccharides obtained from leek have shown good immunostimulating properties. The highest immunostimulating activity has been shown by the water-and chelate-extractable polysaccharides, which are also characterized by a high polyuronic acid content and polysaccharides with molecular mass over 10 6 Da

A study of the effectiveness of the administrative anti-smoking measures in work and public places in the town of Haskovo

Scripta Scientifica Medica 2007; 39(2):115-11

Cell and tissue morphology determine actin-dependent nuclear migration mechanisms in neuroepithelia

Correct nuclear position is crucial for cellular function and tissue development. Depending on cell context, however, the cytoskeletal elements responsible for nuclear positioning vary. While these cytoskeletal mechanisms have been intensely studied in single cells, how nuclear positioning is linked to tissue morphology is less clear. Here, we compare apical nuclear positioning in zebrafish neuroepithelia. We find that kinetics and actin-dependent mechanisms of nuclear positioning vary in tissues of different morphology. In straight neuroepithelia, nuclear positioning is controlled by Rho-ROCK-dependent myosin contractility. In contrast, in basally constricted neuroepithelia, a novel formin-dependent pushing mechanism is found for which we propose a proof-of-principle force generation theory. Overall, our data suggest that correct nuclear positioning is ensured by the adaptability of the cytoskeleton to cell and tissue shape. This in turn leads to robust epithelial maturation across geometries. The conclusion that different nuclear positioning mechanisms are favored in tissues of different morphology highlights the importance of developmental context for the execution of intracellular processes