Biosynthesis of branched polylactosaminoglycans. Embryonal carcinoma cells express midchain beta1,6-N-acetylglucosaminyltransferase activity that generates branches to preformed linear backbones

Two types of beta1,6-GlcNAc transferases (IGnT6) are involved in in vitro branching of polylactosamines: dIGnT6 (distally acting), transferring to the penultimate galactose residue in acceptors like GlcNAcbeta1-3Galbeta1-4GlcNAcbeta1-R, and cIGnT6 (centrally acting), transferring to the midchain galactoses in acceptors of the type (GlcNAcbeta1-3)Galbeta1-4GlcNAcbeta1-3Galbeta1-+ ++4GlcNAcbeta1-R. The roles of the two transferases in the biosynthesis of branched polylactosamine backbones have not been clearly elucidated. We report here that cIGnT6 activity is expressed in human (PA1) and murine (PC13) embryonal carcinoma (EC) cells, both of which contain branched polylactosamines in large amounts. In the presence of exogenous UDP-GlcNAc, lysates from both EC cells catalyzed the formation of the branched pentasaccharide Galbeta1-4GlcNAcbeta1-3(GlcNAcbeta1-6)Galbeta1-4 GlcNAc from the linear tetrasaccharide Galbeta1-4GlcNAcbeta1-3Galbeta1-4GlcNAc. The PA1 cell lysates were shown to also catalyze the formation of the branched heptasaccharides Galbeta1-4GlcNAcbeta1-3Galbeta1-4GlcNAcbeta1-3(+ ++GlcNAcbeta1-6)Galbeta1 -4GlcNAc and Galbeta1-4GlcNAcbeta1-3(GlcNAcbeta1-6)Galbeta1-+ ++4GlcNAcbeta1-3Galbeta1 -4GlcNAc from the linear hexasaccharide Galbeta1-4GlcNAcbeta1-3Galbeta1-4GlcNAcbeta1- 3Galbeta1-4GlcNAc in reactions characteristic to cIGnT6. By contrast, dIGnT6 activity was not detected in the lysates of the two EC cells that were incubated with UDP-GlcNAc and the acceptor trisaccharide GlcNAcbeta1-3Galbeta1-4GlcNAc. Hence, it appears likely that cIGnT6, rather than dIGnT6 is responsible for the synthesis of the branched polylactosamine chains in these cells.     

Tissue biocompatibility of new biodegradable drug-eluting stent materials

Drug-eluting stents are a recent innovation for endovascular and endourethral purposes. The aim of this study was to assess the biocompatibility of new biodegradable drug-eluting stent materials in vivo. Rods made of SR-PLDLA (self-reinforced poly-96l,4d-lactic acid) covered with P(50l/50d)LA and rods made of 96l/4D SR-PLA and covered with P(50l/50d)LA including indomethacin 3.3 μg/mm² or dexamethasone 1.5 μg/mm², were inserted into the dorsal muscles of 20 rabbits serving as test animals. Rods made of silicone and organotin-positive polyvinylchloride were used as negative and positive controls. The animals were sacrificed after 1 week, 1 month, 2 months or 4 months. Histological changes attributable to the operative trauma were seen in all specimens at 1 week and 1 month. At 2 months both dexamethasone and indomethacin induced less fibrosis than the plain SR-PLDLA covered with P(50l/50d)LA without drug. At 4 months dexamethasone induced both chronic inflammatory changes and foreign body reaction, whereas the reactions in the indomethacin and drug-free plain SR-PLDLA groups were insignificant. The new biodegradable drug-eluting stent materials are highly biocompatible. Drug-eluting biodegradable stents may offer a promising new treatment modality for vascular and urethral diseases. However, further studies are needed to demonstrate their feasibility and efficacy.     

Infection of the Sunagoke moss panels with fungal pathogens hampers sustainable greening in urban environments

Drought and heat tolerance of the Sunagoke moss (Racomitrium japonicum) and the low thermal conductivity of the dry moss tissue offer novel greening and insulation possibilities of roofs and walls to mitigate the heat island phenomenon in urban environments. However, damage may appear in the moss panels under humid conditions in Japan. In this study we characterized fungi associated with the damaged areas of the Sunagoke moss panels. Fungi were identified by morphology and internal transcribed spacer (ITS) sequence analysis and tested for pathogenicity on R. japonicum (Grimmiaceae) and an unrelated moss species (Physcomitrella patens; Funariaceae) under controlled conditions. Alternaria alternata, Fusarium avenaceum and Fusarium oxysporum caused severe necrosis and death, whereas Cladosporium oxysporum and Epicoccum nigrum caused milder discoloration or chlorosis in both moss species. The fungi pathogenic on moss were closely related to fungal pathogens described from cultivated vascular plants. Ammonium increased severity of fungal diseases in moss. This study demonstrated that fungi can cause economically significant diseases in cultivated moss and hamper commercial use of the moss panels unless appropriate control methods are developed. Use of a single moss clone to cover large surfaces and the air pollutants such as ammonium may increase the risk for fungal disease problems.     

Effects of esterification on the formation and decomposition of steryl hydroperoxides

The aim of the study was to investigate the effects of esterification on the hydroperoxide formation and decomposition of steryl ester to be able to evaluate early phases of autoxidation. In order to study hydroperoxides of intact steryl esters, a novel HPLC–ELSD method was developed. Steryl ester hydroperoxides were separated using a silica column with heptane-MBTE gradient. The method was applied to study the formation and decomposition of steryl moiety hydroperoxides in cholesteryl stearate during heating at 100 °C. To investigate the effect of esterification, also the formation of hydroperoxides in free cholesterol was measured. To confirm the results obtained by HPLC and to follow the decomposition of the hydroperoxides, peroxide values and secondary oxidation products were determined. The new HPLC showed that 7α- and 7β-OOH were the predominant hydroperoxides. In purified cholesteryl stearate, their amounts were highest (47–62 mg/g) after heating for 2–3 days, and after 4 days only small amounts were found. The formation of secondary oxidation products was marked when the amount of hydroperoxides was high. Presence of impurities in the commercial steryl ester preparation increased significantly the oxidation rate. Free cholesterol oxidised more slowly than the ester. The amount of 7-OOH epimers was only 2.6 mg/g for free cholesterol after 3 days. In conclusion, the new method was shown to be a useful tool for the determination of individual intact steryl ester hydroperoxides. The esterification of sterol affected both the rate of oxidation and the amount of formed oxidation products.     

Alternative Paths to Competitive Advantage: A Fuzzy-Set Analysis of the Origins of Large Firms

Scholars have documented the importance of national-level factors for the competitive success of firms on a global scale. These studies typically identify multiple factors that are behind the emergence of large and successful firms in particular national clusters. However, there has been relatively little research identifying whether such factors are all collectively necessary to produce the outcome, or whether only a few of the factors in different combinations might be sufficient to generate the shift in competitive advantage manifested in the market power of large “flagship” firms. In this paper, we study the evolution of one industry across six countries in which the competitive position of national firms changed considerably during our 100-year analysis period. The results of our combined historical and fuzzy-set analyses show that an unequal distribution of resources may lead to alternative causal pathways to competitive advantage of the largest firms.     

THE PRODUCTION OF AROMA COMPOUNDS BY YEAST

The yeast plasma membrane regulates the movement of compounds into the yeast cell and of yeast metabolites from the cell into the medium. The rate of penetration of organic acids into the yeast cell depends on their lipophilic nature, and on their molecular size and degree of branching. During fermentation yeast synthesizes a vast number of aroma compounds. The numerically and quantitatively largest groups of aroma compounds include fusel alcohols, fatty acids and fatty acid esters. The yeast used and the fermentation conditions can influence the formation of aroma compounds. The yeast also has a profound effect on the formation of other aroma compounds, such as sulphur compounds and phenols. In addition to fermentation, the maturing of a beverage can also influence the aroma. During the maturing lactones, phenols and other compounds are extracted from the oak casks in which the beverage is aged. The presence of the so-called “whisky lactone”, β-methyl-γ-octalactone, is characteristic of a beverage that has been matured in oak.     

Effect of driving experience on anticipatory look-ahead fixations in real curve driving

Anticipatory skills are a potential factor for novice drivers’ curve accidents. Behavioural data show that steering and speed regulation are affected by forward planning of the trajectory. When approaching a curve, the relevant visual information for online steering control and for planning is located at different eccentricities, creating a need to disengage the gaze from the guidance of steering to anticipatory look-ahead fixations over curves. With experience, peripheral vision can be increasingly used in the visual guidance of steering. This could leave experienced drivers more gaze time to invest on look-ahead fixations over curves, facilitating the trajectory planning.