榆干离褶伞溶栓酶对大鼠动脉血栓的抑制作用

目的:研究榆干离褶伞溶栓酶(Lyophyllum ulmarium fibrinolytic enzyme,LUFE)对大鼠动脉血栓形成的抑制作用及其机制.方法:将SD大鼠随机分为假手术组、模型组、阳性对照组和LUFE低、高剂量组,除假手术组以外,其余4组均以三氯化铁建立颈动脉血栓模型.造模前阳性对照组和LUFE低、高...     

Chinese Yam Extracts Containing β‐Sitosterol and Ethyl Linoleate Protect against Atherosclerosis in Apolipoprotein E‐Deficient Mice and Inhibit Muscular Expression of VCAM‐1 In Vitro

Atherosclerosis is a chronic inflammatory disease, which is associated with increased expression of adhesion molecules and monocyte recruitment into the arterial wall. This study evaluated whether hexane extracts from the edible part (DB‐H1) or bark region (DB‐H2) of Dioscorea. batatas Decne have anti‐atherosclerotic properties in vivo and in vitro experiments. We also identified bioactive components in the hexane extracts. Thirty‐six apolipoprotein E (ApoE^?/?) mice and 12 control (C57BL/6J) mice were given a Western‐type diet for 11 or 21 wk. To examine the effects of yam extracts on lesion development, ApoE^?/? mice were orally administered DB‐H1 or DB‐H2 for the duration of the study (200 mg/kg b.w./day, 3 times per wk). Both DB‐H1 and DB‐H2 significantly reduced the total atherosclerotic lesion area in the aortic root. In addition, plasma concentrations of total cholesterol, oxidized‐low‐density lipoprotein, and c‐reactive protein were decreased by administration of DB‐H1 and DB‐H2. Consistent with the in vivo observations, DB‐H1 and DB‐H2 inhibited tumor necrosis factor (TNF)‐α–induced vascular cell adhesion molecule‐1 expression and adhesion of THP‐1 monocytes to TNF‐α–activated vascular smooth muscle cells. It was also found that treatment with DB‐H1 or DB‐H2 resulted in the inhibition nitric oxide (NO) and reactive oxygen species production and iNOS expression in macrophages. Thus, DB‐H1 and DB‐H2 seem to influence atherosclerosis by affecting the production of inflammatory mediators in vivo. Our results suggest that yam extracts have the potential to be used in the prevention of atherosclerosis.     

Effect of In Vitro Digestion on Free α‐Dicarbonyl Compounds in Balsamic Vinegars

We investigated the influence of an in vitro simulated digestion process on the content of the free α‐dicarbonyl compounds most frequently found in food. A Glyoxal (GO), methylglyoxal (MGO), and diacetyl (DA) aqueous standard mixture and 2 brands of balsamic vinegar were analyzed before and after exposure to digestive enzymes. A strong matrix effect required adoption of validated RP‐HPLC‐DAD standard addition methods. The results showed that the digestive enzymes markedly alter the concentrations of the exogenous free α‐dicarbonyl compounds ingested with food; the extent of such changes varied with the α‐dicarbonyl compound itself and the diet components, which determined important but different food matrix effects also during digestion. The data also indicate that digestion can reduce the bioavailability of the toxic α‐dicarbonyl compounds ingested with food. However, no firm conclusions can be drawn about a putative positive influence of digestion on the toxic potential of dietary α‐dicarbonyl compounds, because their reaction in the presence of digestive enzymes likely gives rise to advanced glycation end products, which are involved in the development of chronic diseases.     

Effect of γ‐irradiation on the biophysical and morphological properties of corn

The effects of γ‐irradiation on the biophysical and morphological properties of corn plants were investigated. The irradiation doses were 0, 1, 1.5, 2.5, 5, and 10 krad. Corn grains exposed to 1.5 and 2.5 krad showed highly significant changes in all growth parameters. Fluorescence and light absorption spectra of chlorophyll attributed to different doses treatments of corn grains clearly confirmed the superiority of 1.5 krad irradiation dose in stimulating corn plants. Furthermore, the frequency dependence of the relative permittivity and the electric conductivity of the treated samples have been performed and discussed. The obtained results give another support via the biophysical properties for the 1.5 krad irradiation dose to be the most favorable one to improve the plant growth characteristics.     

Sesamin attenuates intercellular cell adhesion molecule‐1 expression in vitro in TNF‐α‐treated human aortic endothelial cells and in vivo in apolipoprotein‐E‐deficient mice

Sesame lignans have antioxidative and anti‐inflammatory properties. We focused on the effects of the lignans sesamin and sesamol on the expression of endothelial‐leukocyte adhesion molecules in tumor necrosis factor‐α (TNF‐α)‐treated human aortic endothelial cells (HAECs). When HAECs were pretreated with sesamin (10 or 100 μM), the TNF‐α‐induced expression of intercellular cell adhesion molecule‐1 (ICAM‐1) was significantly reduced (35 or 70% decrease, respectively) by Western blotting. Sesamol was less effective at inhibiting ICAM‐1 expression (30% decrease at 100 μM). Sesamin and sesamol reduced the marked TNF‐α‐induced increase in human antigen R (HuR) translocation and the interaction between HuR and the 3'UTR of ICAM‐1 mRNA. Both significantly reduced the binding of monocytes to TNF‐α‐stimulated HAECs. Sesamin significantly attenuated TNF‐α‐induced ICAM‐1 expression and cell adhesion by downregulation of extracellular signal‐regulated kinase 1/2 and p38. Furthermore, in vivo, sesamin attenuated intimal thickening and ICAM‐1 expression seen in aortas of apolipoprotein‐E‐deficient mice. Taken together, these data suggest that sesamin inhibits TNF‐α‐induced extracellular signal‐regulated kinase/p38 phosphorylation, nuclear translocation of NF‐κB p65, cytoplasmic translocalization of HuR and thereby suppresses ICAM‐1 expression, resulting in reduced adhesion of leukocytes. These results also suggest that sesamin may prevent the development of atherosclerosis and inflammatory responses.     

Screening of β‐Glucosidase and β‐Xylosidase Activities in Four Non‐Saccharomyces Yeast Isolates

The finding of new isolates of non‐Saccharomyces yeasts, showing beneficial enzymes (such as β‐glucosidase and β‐xylosidase), can contribute to the production of quality wines. In a selection and characterization program, we have studied 114 isolates of non‐Saccharomyces yeasts. Four isolates were selected because of their both high β‐glucosidase and β‐xylosidase activities. The ribosomal D1/D2 regions were sequenced to identify them as Pichia membranifaciens Pm7, Hanseniaspora vineae Hv3, H. uvarum Hu8, and Wickerhamomyces anomalus Wa1. The induction process was optimized to be carried on YNB‐medium supplemented with 4% xylan, inoculated with 106 cfu/mL and incubated 48 h at 28 °C without agitation. Most of the strains had a pH optimum of 5.0 to 6.0 for both the β‐glucosidase and β‐xylosidase activities. The effect of sugars was different for each isolate and activity. Each isolate showed a characteristic set of inhibition, enhancement or null effect for β‐glucosidase and β‐xylosidase. The volatile compounds liberated from wine incubated with each of the 4 yeasts were also studied, showing an overall terpene increase (1.1 to 1.3‐folds) when wines were treated with non‐Saccharomyces isolates. In detail, terpineol, 4‐vinyl‐phenol and 2‐methoxy‐4‐vinylphenol increased after the addition of Hanseniaspora isolates. Wines treated with Hanseniaspora, Wickerhamomyces, or Pichia produced more 2‐phenyl ethanol than those inoculated with other yeasts.     

Effect of heat shock protein 27 on the in vitro degradation of myofibrils by caspase‐3 and μ‐calpain

This study was designed to investigate the effect of heat shock protein 27 (HSP27) on the in vitro degradation of myofibrils induced by caspase‐3 or μ‐calpain. Myofibrillar proteins were prepared from at‐death beef muscles and incubated with caspase‐3 or μ‐calpain with and without HSP27, or with HSP27 alone, at 30 °C for 2 h, and protein degradation was assessed. Results showed that caspase‐3 promoted the degradation of titin, nebulin and troponin‐T, and μ‐calpain promoted the degradation of nebulin, desmin and troponin‐T, observed during normal PM ageing. Moreover, the addition of HSP27 restricted the degradation of troponin‐T in μ‐calpain‐ and caspase‐3‐treated myofilaments, and restricted the degradation of desmin in μ‐calpain‐treated myofilaments. Therefore, HSP27 may indirectly or directly interact with caspase‐3 and μ‐calpain, reducing their activity and mediating PM proteolysis of muscle proteins to affect meat tenderisation.     

Effect of γ‐aminobutyric acid on the physicochemical,rheological and sensory properties of yoghurt

This study aimed to investigate the impacts of dairy processing conditions on the γ‐aminobutyric acid (GABA) content and the effect of GABA on the quality of the resulting yoghurt. Serial concentrations of GABA (0.05–1.0%, w/w, milk basis) were designed during the preparation of yoghurt. Colour and physicochemical and rheological properties of yoghurt were also examined. The results indicated that the fermentation process had no significant influence on GABA content. The GABA level greatly improved the texture properties of the resulting product at a concentration of 0.5% (w/w), whereas higher GABA concentrations impaired the texture. The lightness (L) value of yoghurt also increased in line with the GABA concentration.     

Contribution of cysteine and glutathione conjugates to the formation of the volatile thiols 3‐mercaptohexan‐1‐ol (3MH) and 3‐mercaptohexyl acetate (3MHA) during fermentation by Saccharomyces cerevisiae

Background and Aims: 3‐Mercaptohexan‐1‐ol (3MH) and its ester 3‐mercaptohexyl acetate (3MHA) are potent aromatic thiols that substantially contribute to varietal wine aroma. During fermentation, non‐volatile 3MH conjugates are converted by yeast to volatile 3MH and 3MHA. Two types of 3MH conjugates have been identified, S‐3‐(hexan‐1‐ol)‐L‐cysteine (Cys‐3MH) and S‐3‐(hexan‐1‐ol)‐glutathione (GSH‐3MH). Yeast‐driven formation of 3MH from these precursors has been previously demonstrated, while the relationship between 3MHA and GSH‐3MH remains to be established. This paper aims to investigate yeast conversion of GSH‐3MH to 3MH and 3MHA, and to assess the relative contribution of each individual conjugate to the 3MH/3MHA pool of finished wines. Methods and Results: Fermentation experiments were carried out in model grape juice containing Cys‐3MH and GSH‐3MH. We found 3MH formation from GSH‐3MH to be significantly less efficient than that of Cys‐3MH. Conversely, esterification of 3MH to 3MHA was higher when 3MH was formed from GSH‐3MH. Additional in vitro assays for measuring enzyme cleavage activity suggest the involvement of a different mechanism in 3MH conversion for the two precursors. Conclusions: These results indicate that although both 3MH conjugates can be converted by yeast, the type of precursor affects the rate of formation of 3MH and 3MHA during fermentation. Significance of the Study: Management of the pool of aromatic thiols during fermentation can depend on relative proportions of different 3MH conjugates.     

Studies on the interaction of ‐epigallocatechin‐3‐gallate from green tea with bovine β‐lactoglobulin by spectroscopic methods and docking

The binding interaction between‐epigallocatechin‐3‐gallate (EGCG) and bovine β‐lactoglobulin (βLG) was thoroughly studied by fluorescence, circular dichroism (CD) and protein–ligand docking. Fluorescence data revealed that the fluorescence quenching of βLG by EGCG was the result of the formation of a complex of βLG–EGCG. The binding constants and thermodynamic parameters at two different temperatures and the binding force were determined. The binding interaction between EGCG and βLG was mainly hydrophobic and the complex was stabilised by hydrogen bonding. The results suggested that βLG in complex with EGCG changes its native conformation. Furthermore, preheat treatment (90 °C, 120 °C) and emulsifier (sucrose fatty acid ester) all boosted the binding constants (K_a) and the binding site values (n) of the βLG‐EGCG complex. This study provided important insight into the mechanism of binding interactions of green tea flavonoids with milk protein.     

Effect of γ‐aminobutyric acid supplementation on the composition of Chinese rice wine

This study investigated the effect of γ‐aminobutyric acid (GABA) supplementation on the composition of Chinese rice wine. GABA was added at 188.5 and 377 mg/L at the beginning of primary fermentation or post‐fermentation. Addition of GABA during primary fermentation had no impact on alcohol and total acid formation or the utilisation of sugar. However, total free amino acids, total essential amino acids and GABA in rice wine supplemented with GABA were significantly lower than the control rice wine without supplementation. Alcohol formation, total acid, sugar content and total essential amino acids were similar compared with the control. However, the GABA post‐supplementation was significantly higher, suggesting that GABA supplementation post‐fermentation process could enhance the GABA content in rice wine. © 2018 The Institute of Brewing & Distilling