The role of ions on histamine-induced depolarization in isolated guinea pig adipocytes

Effects of ions on histamine (Hi)-induced depolarization were studied in guinea pig adipocytes. Depolarization induced by Hi in guinea pig adipocytes was decreased by removal of K+ from the medium or pretreatment with ouabain at concentrations that showed no significant effect themselves. The decrease in membrane potentials induced by Hi was also abolished potently by replacement of Na+ by choline or pretreatment with tetrodotoxin at a concentration that caused no significant action alone. Pretreatment with monensin at a concentration lower than that eliciting the action resulted in a potentiation of Hi-induced depolarization. The depolarization induced by Hi was not affected by the presence of Ca2+ in the medium or pretreatment of the cells by diltiazem.     

Effects of ubiquitin C-terminal hydrolase L1 deficiency on mouse ova

Maternal proteins are rapidly degraded by the ubiquitin-proteasome system during oocyte maturation in mice. Ubiquitin C-terminal hydrolase L1 (UCHL1) is highly and specifically expressed in mouse ova and is involved in the polyspermy block. However, the role of UCHL1 in the underlying mechanism of polyspermy block is poorly understood. To address this issue, we performed a comprehensive proteomic analysis to identify maternal proteins that were relevant to the role of UCHL1 in mouse ova using UCHL1-deficient gad. Furthermore, we assessed morphological features in gad mouse ova using transmission electron microscopy. NACHT, LRR, and PYD domain-containing (NALP) family proteins and endoplasmic reticulum (ER) chaperones were identified by proteomic analysis. We also found that the 'maternal antigen that embryos require' (NLRP5 (MATER)) protein level increased significantly in gad mouse ova compared with that in wild-type mice. In an ultrastructural study, gad mouse ova contained less ER in the cortex than in wild-type mice. These results provide new insights into the role of UCHL1 in the mechanism of polyspermy block in mouse ova.     

Suppression of inducible nitric oxide synthase expression and amelioration of lipopolysaccharide-induced liver injury by polyphenolic compounds in Eucalyptus globulus leaf extract

Eucalyptus leaf extract (ELE) is rich in hydrolyzable tannins. We examined the effects of ELE and its constituents on lipopolysaccharide (LPS)-induced liver injury in mice. Mice fed a diet supplemented with 1% ELE were intraperitoneally administered LPS. Six hours later, the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were significantly lower in the ELE-supplemented mice than in the controls; LPS-induced hepatic inducible nitric oxide synthase (iNOS) expression was also suppressed. ELE lowered LPS-stimulated iNOS expression in cultured RAW 264.7 macrophages. Furthermore, the aglycones of hydrolyzable tannins, gallic acid (GA) and ellagic acid (EA), inhibited iNOS induction to a greater extent than did ELE (15-fold higher). When mice were fed a 1% GA or EA diet, the increase in the serum ALT and AST activities and hepatic iNOS expression in response to the LPS challenge were significantly attenuated. Thus, hydrolyzable tannins in ELE ameliorate LPS-induced liver injury.     

Effects of dietary α-lipoic acid enantiomers on hepatic fatty acid metabolism in rats

Effects of dietary α-lipoic acid enantiomers on hepatic and serum lipid concentrations and the activity and mRNA levels of enzymes involved in hepatic fatty acid metabolism were examined in rats. Rats were fed experimental diets containing 0 or 2.5 g/kg of α-lipoic acid enantiomers (a racemic mixture of R/S-, S- or R-α-lipoic acid) for 21 days. Various α-lipoic acid preparations decreased serum and liver concentrations of triacylglycerol, and also lowered serum concentrations of cholesterol and phospholipid and the concentration of cholesterol in the liver. α-Lipoic acid decreased the activity and mRNA levels of various hepatic lipogenic enzymes and also decreased the activities of carnitine acyltransferase and 3-ketoacyl-CoA thiolase and mRNA levels of carnitine palmitoyltransferase 1a involved in fatty acid oxidation in the liver; however, R- and S-enantiomers of α-lipoic acid as well as well as a racemic mixture of R/S-α-lipoic acid were indistinguishable in altering these indices for lipid metabolism.     

Polyarginine segments in block copolypeptides drive both vesicular assembly and intracellular delivery

Polymeric vesicles are a relatively new class of nanoscale self-assembled materials that show great promise as robust encapsulants. Compared with liposomes, use of polymeric building blocks for membrane formation allows increased stability, stimuli responsiveness and chemical diversity, which may prove advantageous for drug-delivery applications . A major drawback of most polymeric vesicles is the lack of biofunctionality, which restricts their ability to interact with cells and tissues. We have prepared vesicles composed of polyarginine and polyleucine segments that are stable in media, can entrap water soluble species, and can be processed to different sizes and prepared in large quantities. The remarkable feature of these materials is that the polyarginine segments both direct structure for vesicle formation and provide functionality for efficient intracellular delivery of the vesicles. This unique synergy between nanoscale self-assembly and inherent peptide functionality provides a new approach for design of multifunctional materials for drug delivery.     

Influence of microwave roasting on positional distribution of fatty acids of triacylglycerols and phospholipids in sunflower seeds (Helianthus annuus L.)

Whole sunflower seeds were exposed to microwave roasting for 6, 12, 20 or 30 min at a frequency of 2450 MHz. The kernels were then separated from the sunflower seeds, and the lipid components and the positional distribution of fatty acids in triacylglycerols (TAGs) and phospholipids (PLs) were investigated. Major lipid components were TAGs and PLs, while steryl esters, free fatty acids and diacylglycerols were also present in minor proportions. The greatest PL losses (p < 0.05) were observed in phosphatidyl ethanolamine, followed by phosphatidyl choline or phosphatidyl inositol. Significant differences (p < 0.05) in fatty acid distributions occurred (with few exceptions) when sunflower seeds were microwaved for 20 min or more. Nevertheless, the principal characteristics for the positional distribution of fatty acids still remained after 20 min of microwave roasting; unsaturated fatty acids, especially linoleic, were predominantly concentrated in the sn‐2‐position and saturated fatty acids, especially stearic and palmitic acids, primarily occupied the sn‐1‐ or sn‐3‐position. These results indicate that no significant changes in fatty acid distribution of TAGs and PLs would occur within 12 min of microwave roasting, ensuring that a good‐quality product would be attained.     

Effectiveness of spatial representation in the formation of network communities: experimental study on community organizer

In this paper, we present and discuss Community Organizer, a system designed to support network communities. The main characteristic of Community Organizer is the use of spatial representations for the relationships among community members including the communications exchanged among these members. These spatial representations reflect the degree of closeness of interests and concerns among the members, and are intended to provide users with clues on how to form network communities. In order to investigate the effectiveness of the proposed spatial representations, we conducted experiments with two different versions of the software. One version offered meaningful spatial representations while the other version did not. The subjects who used the former software version felt a greater sense of ‘community’, enjoyed using the software more, and actively used it longer than the subjects using the latter software version (control condition). These results indicated that the proposed spatial representations are effective in supporting network community formation.