BBLN-1 is essential for intermediate filament organization and apical membrane morphology

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The role of calcium in agonist-stimulated hydrolysis of phosphatidylinositol in mouse pancreas

The effects of Ca²⁺ on agonist-stimulated hydrolysis of myo-[2-³H]inostol-labelled phosphatidylinositol in mouse pancreas in vitro, were studied. The increase in cytosol Ca²⁺ concentration produced by the ionophore A23187 did not stimulate the breakdown of phosphatidylinositol. Cholecystokinin-octapeptide (CCK-8) stimulated the hydrolysis of phosphatidylinositol under conditions in which intracellular calcium stores were depleted. The breakdown of phosphatidylinositol was stimulated by bethanechol and CCK-8 in Ca²⁺-free Krebs solution, and the addition of Ca²⁺ to the medium potentiated the effects of these agonists. Lanthanum significantly reduced bethanechol and CCK-8 stimulated hydrolysis of phosphatidylinositol in Krebs solution, but was without effect in Ca²⁺-free Krebs solution. The results of this study support the proposal that PI hydrolysis does not occur as a result of Ca²⁺ mobilization and may be involved in Ca²⁺ gating in the pancreas.     

Ultrastructure of wheat straw cell wall delignified by Pleurotus ostreatus

Abstract Transmission electron microscopy of wheat straw cell wall incubated with Pleurotus ostreatus in the presence of glucose or sunflower oil reveals different degradation patterns. Lower lignin content and increased polyphenol-oxidase activity correspond to peculiar features of the substrate at ultrastructural level. Differentiation between cellulose and lignin degradation by electron microscopy might represent a valuable tool to monitor biological delignification during industrial hydrolysis of ligno-cellulose.     

Reaction pathways for Zn(II)-catalyzed carboxylic acid esters hydrolysis

Reaction pathways have been investigated by quantum-mechanical procedures on gas phase models for the hydrolysis of methyl acetate catalyzed by a monohydroxo-Zn(II) complex formed by a phenanthroline-containing polyamine macrocycle. Based on consideration of energy barrier heights, the hydrolysis process is predicted to be bimolecular, consistently with kinetic data obtained for the hydrolysis of p-nitrophenyl acetate promoted by the modelled catalyst. Differences with respect to results of theoretical studies on the more extensively investigated hydrolysis processes catalyzed by the OH⁻ anion are discussed and appear to be mostly due to the presence of the metal centre close to the OH function in the system now investigated. The pervasive presence and path-controlling role of hydrogen bonds are also discussed.     

Modulation of immobilized enzyme activity by altering the hydrophobicity of nylon-grafted membranes: Part 2: Non-isothermal conditions

Lactose hydrolysis by β-galactosidase immobilized on two nylon membranes, differently grafted, has been studied in a bioreactor operating under isothermal and non-isothermal conditions. One membrane (M₁) was obtained by chemical grafting of methylmethacrylate (MAA); the other one (M₂) by a double chemical grafting: styrene (Sty) and MAA. Hexamethylenediamine was used as a spacer between the grafted membranes and the enzyme. Both membranes have been physically characterized studying their permeabilities in presence of pressure or temperature gradients. Under non-isothermal conditions, the increase in activity of membrane M₂ was higher than that of membrane M₁. The and β coefficients, giving the percentage of activity increase when a temperature difference of 1°C is applied across the catalytic membranes, have been calculated. Results have been discussed with reference to the greater hydrophobicity of membrane M₂ with respect to membrane M₁, the hydrophobicity being a prerequisite for the occurrence of the process of thermodialysis.     

Plasmatubules in the pollen tubes of Nicotiana sylvestris

Ultrastructural studies of the pollen tubes of Nicotiana sylvestris grown in the pistil revealed an extensive development of plasmatubules formed by evaginations of the plasma membrane. The plasmatubules occurred as twisted tubular structures in the periplasmic space along the tube wall and, in cross section, exhibited circular profiles with an outer diameter of 28±4 nm. They were also seen in deep, pocket-like invaginations of the plasma membrane and in this case the profiles had an outer diameter of 34±8 nm. In the pocket-like invaginations they were partially branched and often closely packed to form groups with obvious patterns. The enlargement of the plasma-membrane area resulting from plasmatubules formed along the tube wall was about six-to tenfold. Pollen tubes grown in vitro exhibited poorly developed plasmatubules. It is suggested that the large extension of the plasma membrane could enhance the uptake of nutrients, and thus might be responsible for the comparatively fast growth of pollen tubes in the pistil. Moreover, it is also assumed that the turnover rate of the Golgi apparatus must be higher in pollen tubes growing in vivo than in vitro, in order to provide a sufficient amount of membrane for the formation of the plasma membrane with its tubular modifications.     

纸浆废料生物炼制细菌纤维素的研究

细菌纤维素(bacterial cellulose,BC)是一种由微生物产生的具有纳米结构的纤维素材料。BC生产的培养基成本偏高,限制了其规模化工业生产和商业应用。为开发新的BC生产原料,通过Cellic CTec 2纤维素酶直接水解硫酸盐和亚硫酸盐两种纸浆废料获得可发酵糖,以其成功制备出BC并研究比较了两种酶解液对BC产量和结构的差异。结果表明,硫酸盐纸浆废料获得的BC产量最高,达9.0 g/L,比亚硫酸盐纸浆废料的7.7 g/L高了17%。两种原料制备的BC膜的结晶度分别为61%和66%,比葡萄糖制备的(78%)低。红外光谱分析表明,不同碳源制备的BC膜的成分没有明显差异。     

Preconceptional folic acid‐containing supplement use in the national birth defects prevention study

Background: Despite public health campaigns encouraging women to take a daily folic acid supplement, the proportion of reproductive age women, in the United States, who comply with this recommendation is less than optimal. The objective of this analysis was to identify predictors of preconceptional folic acid‐containing supplement use to define subgroups of women who may benefit from targeted folic acid campaigns. Methods: This study included 6570 mothers of live born infants from the control population of National Birth Defects Prevention Study (1997–2005). Logistic regression analyses were used to identify predictors of preconceptional folic acid supplementation. A classification and regression tree (CART) analysis was used to define subgroups of women with different patterns of preconceptional folic acid supplementation. Results: Race/ethnicity, education, age at delivery, nativity, employment, income, number of dependents, smoking, and birth control use were significantly associated with preconceptional folic acid‐containing supplement use. Based on a CART analysis, education, race/ethnicity, and age were the most distinguishing factors between women with different preconceptional supplementation patterns. Non‐white women with <4 years of a college education were the least likely to use folic acid‐containing supplements (11%). However, even in the most compliant subgroup (women with ≥4 years of college), only 60% of women supplemented with folic acid. Conclusion: These results demonstrate the need for continued efforts to increase folic acid supplementation among all reproductive aged women. However, the success of such efforts may be improved if maternal characteristics such as education, race/ethnicity, and age, are considered in the development of future interventions. Birth Defects Research (Part A) 100:472–482, 2014. © 2014 Wiley Periodicals, Inc.