山楂、甾醇酯及功能红曲复配物的降血脂活性

目的:研究山楂、甾醇酯及功能红曲复配物的降血脂效果及机制。方法:将6周龄体重为(100±10)g的SPF级雄性仓鼠随机分为正常组N、模型组C、单纯山楂干预组A,山楂+低剂量甾醇酯组B,山楂+高剂量甾醇酯组D,山楂+甾醇酯+低剂量功能红曲组E,山楂+甾醇酯+高剂量功能红曲组F。每2周称重并检测其血脂指标,8周后处死。测定其血脂指标(总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白(HDL-c);计算脏器及脂重指数、非高密度脂蛋白(non-HDL-c)含量、动脉硬化指数(AI);观察肝脏及主动脉病理切片,胆固醇代谢调控相关基因的mRNA表达水平。结果:F组与高脂对照组相比,小鼠体重、肝脏指数、脂重指数及TC、TG、non-HDL-c、AI极显著下降(P<0.01),HDL-c显著上升(P<0.05);粪便中胆酸含量极显著上升(P<0.01);肝脏组织脂肪变性程度和主动脉粥样硬化症状有所改善;CYP7A1mRNA表达水平显著上调(P<0.05),LXRα、PPARα及FXR极显著上调(P<0.01),LIMA1、NPC1L1的mRNA表达水平显著下调(P<0.05),HMG-CoA-R、SREBP2极显著下调(P<0.01)。结论:F组降脂效果最佳,即3种天然物质的复配从增加体内胆固醇排出体外、减少机体对胆固醇的吸收以及减少胆固醇的自身合成3个途径有效预防因长期高脂饮食导致的高脂血症。     

超临界CO2萃取技术在油脂工业中的应用

综述了超临界萃取技术在油脂工业的应用现状，其中对油脂、脂肪酸、生育酚、胡萝卜素、磷脂、甾醇等萃取现状进行了分析，并对超临界技术的发展方向及其在油脂工业的应用前景进行了介绍。     

番木瓜籽油的营养特性及稳定性

以番木瓜籽为研究对象,采用溶剂提取法提取番木瓜籽油,运用GC-MS对番木瓜籽油脂肪酸组成进行分析,对其理化性质和脂溶性伴随物含量进行检测,并对其抗氧化活性及稳定性进行研究。结果表明:以正己烷为提取溶剂,番木瓜籽油得率为(28.62±0.27)%;番木瓜籽油富含不饱和脂肪酸(86.54%),主要是油酸((44.03±1.21)%)和亚油酸((42.25±1.32)%),脂溶性伴随物主要有β-谷甾醇((5.11±0.16) mg/kg)、菜油甾醇((0.33±0.02) mg/kg)、生育酚((150.41±3.13) mg/kg);此外,番木瓜籽油酸值(KOH)((1.25±0.15) mg/g)、过氧化值((0.25±0.04)mmol/kg)均符合GB 2716—2018要求;番木瓜籽油对DPPH自由基和羟自由基均有较好的清除效果,IC50值分别为9.21 mg/m L和0.53 mg/m L,同时还具有较好的储藏稳定性和热加工稳定性。番木瓜籽可作为一种潜在的油料资源。     

XIII. Yeast sequencing reports. SED6 is identical to ERG6, and encodes a putative methyltransferase required for ergosterol synthesis

Luminal endoplasmic reticulum (ER) proteins carry a sorting signal that allows them to be retrieved from the Golgi apparatus by a specific receptor. In yeast, this receptor is encoded by the ERD2 gene. Although retrieval of ER proteins does not appear to be an essential process, cells lacking ERD2 do not grow. Several multicopy suppressors of this growth defect have been isolated. The sequence of one of these, SED6, is presented here. Its product contains motifs characteristic of methyltransferases, and it is identical to ERG6, the presumed structural gene for S-adenosylmethionine:Δ²⁴-sterol-C-methyltransferase. The gene is located adjacent to PDR4, near the centromere of chromosome XIII.     

The yeast Saccharomyces cerevisiae Pdr16p restricts changes in ergosterol biosynthesis caused by the presence of azole antifungals

Pdr16p belongs to the family of phosphatidylinositol transfer proteins in yeast. The absence of Pdr16p results in enhanced susceptibility to azole antifungals in Saccharomyces cerevisiae. In the major fungal human pathogen Candida albicans, CaPDR16 is a contributing factor to clinical azole resistance. The current study was aimed at better understanding the function of Pdr16p, especially in relation to azole resistance in S. cerevisiae. We show that deletion of the PDR16 gene increased susceptibility of S. cerevisiae to azole antifungals that are used in clinical medicine and agriculture. Significant differences in the inhibition of the sterol biosynthetic pathway were observed between the pdr16Δ strain and its corresponding wild‐type (wt) strain when yeast cells were challenged by sub‐inhibitory concentrations of the azoles miconazole or fluconazole. The increased susceptibility to azoles, and enhanced changes in sterol biosynthesis upon exposure to azoles of the pdr16Δ strain compared to wt strain, are not the results of increased intracellular concentration of azoles in the pdr16Δ cells. We also show that overexpression of PDR17 complemented the azole susceptible phenotype of the pdr16Δ strain and corrected the enhanced sterol alterations in pdr16Δ cells in the presence of azoles. Pdr17p was found previously to be an essential part of a complex required for intermembrane transport of phosphatidylserine at regions of membrane apposition. Based on these observations, we propose a hypothesis that Pdr16p assists in shuttling sterols or their intermediates between membranes or, alternatively, between sterol biosynthetic enzymes or complexes. Copyright © 2013 John Wiley & Sons, Ltd.     

Evaluation of hypolipidemic effects of peanut skin-derived polyphenols in rats on Western-diet

The effect of water soluble polyphenolic extract of peanut skin (PE) was investigated for its hypolipidemic properties in rats on Western diet. Seven-weeks old Wistar rats received control diet (AIN-93G), Western diet with and without a bolus of PE five times a week for 10weeks. Group which received 300mg/kg body weight showed significantly reduced body weight and epididymal fat. Plasma and liver triglyceride (TG) and cholesterol (TC) levels were significantly reduced while faecal secretion of TG and TC was greatly increased upon PE administration. Liver mRNA expression of enzymes involved in fatty acid synthesis, such as fatty acid synthase (FAS), sterol receptor element binding protein (SREBP)-1c, acetyl-CoA carboxylase (ACC1) and lipid uptake genes, such as PPARγ, were decreased, while PPARα was up-regulated by administration of PE. These data suggest that administration of PE may contribute to the improved lipid homoeostasis in rats on diets high in cholesterol and lipids.     

烟草甾醇合成代谢分子调控研究进展

烟叶中的甾醇在卷烟燃烧过程中生成致癌物-多环芳烃(PAHs)。笔者主要阐述了植物甾醇在卷烟减害研究、调控植物生长发育和响应植物胁迫中的作用,重点介绍了植物甾醇合成代谢途径以及该途径中的关键酶基因。