Bioconversion of green volatiles in okara (soybean residue) into esters by coupling enzyme catalysis and yeast (Lindnera saturnus) fermentation

Okara (soybean residue), a by-product from soymilk and tofu production, has a green, grassy off odour as it contains a large amount of aldehydes. This work investigated the rate-limiting enzyme(s) in the formation of aldehydes in okara and the pathways leading to their bioconversion into fruity, pleasant-smelling esters by the yeast Lindnera saturnus. Lipase and hydroperoxide lyase were shown to be rate-limiting enzymes while endogenous soy lipoxygenase was also crucial for the production of aldehydes in okara. Subsequent fermentation of okara by L. saturnus increased the amount of esters by about 70 times to 165–277 μg/g dried okara. The generation of C7 esters followed our hypothesised pathway, while that for C6 esters was mainly affected by L. saturnus. This study presents a simple and inexpensive one-pot setup for the natural bio-production of esters from okara.

     

组蛋白去乙酰化酶抑制剂调控干细胞分化与体细胞重编程的研究进展

表观遗传调控,如组蛋白乙酰化修饰,是决定干细胞分化方向的重要机制。组蛋白去乙酰化酶抑制剂(HDACi)通过影响不同亚类的组蛋白去乙酰化酶(HDAC)活性,提高组蛋白乙酰化水平,调控基因表达,从而影响胚胎干细胞自我更新,以及沿神经元、心肌和造血等细胞谱系的定向分化。HDACi类小分子化合物在体细胞重编程中也有广泛的应用,可替代致癌因子c-Myc和Klf4,促进体细胞克隆。研究显示,HDACi的效应与药物剂量、细胞类型和细胞分化状态密切相关。本文主要阐述了HDACi在干细胞分化和体细胞重编程中的应用进展,并对所涉及的分子通路进行讨论,有助于揭示干细胞定向分化的关键分子机制,优化干细胞定向分化诱导策略,对干细胞诱导分化具有重要的理论和实用价值。     

Distinct Associations between Hypertension and Obstructive Sleep Apnea in Male and Female Patients

Obstructive sleep apnea (OSA) is highly associated with hypertension. However, the correlation between hypertension and OSA at different levels of severity and the influence of gender on that correlation are unclear. A total of 996 patients (776 males and 190 females) with OSA were recruited. The influence of gender on the correlation between hypertension and OSA at different stratifications of severity, based on the apnea-hypopnea index (AHI), was fully evaluated together with the major health risk factors obesity, age, and diabetes. Females with OSA were significantly older on average than males with OSA. Moreover, females had milder degrees of OSA on average than the extent of severity seen in males. The proportion of females with diabetes or hypertension was higher than that of males. The proportion of males with hypertension and obesity increased significantly with OSA, and age also increased with OSA. The percentage of females with hypertension at different degrees of OSA severity was stable at about 26% in the mild, moderate, and severe OSA groups. Among females, age was increased significantly in the moderate relative to the mild OSA group. Moreover, the proportion of obese subjects was increased significantly in the severe compared with the moderate OSA group. The proportions of males and females with diabetes were not significantly different among all OSA severity groups. An ordinal multivariate logistic regression analysis confirmed that hypertension, age, and obesity were associated with OSA severity in males, whereas only age and obesity were associated with OSA severity in females. Although the proportion of subjects with hypertension was higher in females with OSA than in males with OSA, the proportion of subjects with hypertension increased as the severity of OSA increased in males but not in females.     

樟子松人工固沙林天然更新特征

采用比较分析与野外调查的方法。对沙地樟子松人工林天然更新特征进行了研究,能够进行天然更新的引种地区天然更新在时间上是不连续的,与特定年份的某些降水因子密切相关;在空间上主要有3种更新方式;林隙更新,林缘更新,阔叶林下更新;天然更新幼树生长情况与人工林的生长差异不大。     

全球变暖对太行山植被生产力及土壤水分的影响

将相同的自然植被用Lysimeter从高海拔下移至低海拔,温度升高2℃,同时设置平均降水,增加10％降水,增加20％降水,减少10％降水和减少20％降水5个降水处理,模拟全球变暖带来的温度升高和降水变化对植被生产力和土壤水分的影响,两年的野外实验表明,温度升高造成生态适应性差的野古草（Arundinelia hirta)生产力显著下降,致使整个测试群落生产力降低,低海拔实验点生产力显著低于高海拔实验点,温度升高对铁杆（Artemisia sacrorum)和黄背草（Themeda japonica)的影响较小,太行山区的植被对降水的变化反映,降水增加使植被的生产力水平显著提高,其中降水增加20％的处理生产力比平均降水处理的生产力增加22％,增加降水处理的土壤含水量显著高于平均降水和降水减少的实验处理,由于植被的减少,温度升高的实验点从第二年开始土壤水分较高。     

Genetic Diversity and Population Structure of Cucumber (Cucumis sativus L.)

Knowing the extent and structure of genetic variation in germplasm collections is essential for the conservation and utilization of biodiversity in cultivated plants. Cucumber is the fourth most important vegetable crop worldwide and is a model system for other Cucurbitaceae, a family that also includes melon, watermelon, pumpkin and squash. Previous isozyme studies revealed a low genetic diversity in cucumber, but detailed insights into the crop''s genetic structure and diversity are largely missing. We have fingerprinted 3,342 accessions from the Chinese, Dutch and U.S. cucumber collections with 23 highly polymorphic Simple Sequence Repeat (SSR) markers evenly distributed in the genome. The data reveal three distinct populations, largely corresponding to three geographic regions. Population 1 corresponds to germplasm from China, except for the unique semi-wild landraces found in Xishuangbanna in Southwest China and East Asia; population 2 to Europe, America, and Central and West Asia; and population 3 to India and Xishuangbanna. Admixtures were also detected, reflecting hybridization and migration events between the populations. The genetic background of the Indian germplasm is heterogeneous, indicating that the Indian cucumbers maintain a large proportion of the genetic diversity and that only a small fraction was introduced to other parts of the world. Subsequently, we defined a core collection consisting of 115 accessions and capturing over 77% of the SSR alleles. Insight into the genetic structure of cucumber will help developing appropriate conservation strategies and provides a basis for population-level genome sequencing in cucumber.     

Genetic deletion of low density lipoprotein receptor impairs sterol-induced mouse macrophage ABCA1 expression. A new SREBP1-dependent mechanism

Low density lipoprotein receptor (LDLR) mutations cause familial hypercholesterolemia and early atherosclerosis. ABCA1 facilitates free cholesterol efflux from peripheral tissues. We investigated the effects of LDLR deletion (LDLR(-/-)) on ABCA1 expression. LDLR(-/-) macrophages had reduced basal levels of ABCA1, ABCG1, and cholesterol efflux. A high fat diet increased cholesterol in LDLR(-/-) macrophages but not wild type cells. A liver X receptor (LXR) agonist induced expression of ABCA1, ABCG1, and cholesterol efflux in both LDLR(-/-) and wild type macrophages, whereas expression of LXRalpha or LXRbeta was similar. Interestingly, oxidized LDL induced more ABCA1 in wild type macrophages than LDLR(-/-) cells. LDL induced ABCA1 expression in wild type cells but inhibited it in LDLR(-/-) macrophages in a concentration-dependent manner. However, lipoproteins regulated ABCG1 expression similarly in LDLR(-/-) and wild type macrophages. Cholesterol or oxysterols induced ABCA1 expression in wild type macrophages but had little or inhibitory effects on ABCA1 expression in LDLR(-/-) macrophages. Active sterol regulatory element-binding protein 1a (SREBP1a) inhibited ABCA1 promoter activity in an LXRE-dependent manner and decreased both macrophage ABCA1 expression and cholesterol efflux. Expression of ABCA1 in animal tissues was inversely correlated to active SREBP1. Oxysterols inactivated SREBP1 in wild type macrophages but not in LDLR(-/-) cells. Oxysterol synergized with nonsteroid LXR ligand induced ABCA1 expression in wild type macrophages but blocked induction in LDLR(-/-) cells. Taken together, our studies suggest that LDLR is critical in the regulation of cholesterol efflux and ABCA1 expression in macrophage. Lack of the LDLR impairs sterol-induced macrophage ABCA1 expression by a sterol regulatory element-binding protein 1-dependent mechanism that can result in reduced cholesterol efflux and lipid accumulation in macrophages under hypercholesterolemic conditions.     

噪声和二硫化碳对大鼠外膝体神经元光反应的影响及其联合效应

目的：观察噪声或二硫化碳（CS2）暴露对大鼠外侧膝状体（LGB）神经元光反应的影响及二者的联合效应。方法：脉冲噪声刺激和光栅刺激由计算机控制输出,CS2通过皮下注射,运用电生理学方法记录LGB神经元电活动。结果：噪声暴露后有21％的神经元光反应被抑制,当噪声持续时,抑制程度有增强的趋势,呈现出剂量效应关系。不同剂量的CS2暴露,神经元受到不同程度的抑制,亦呈剂量一效应关系。噪声和CS2同时作用时,呈一定的协同作用。结论：噪声或者CS2的单独作用可明显抑制外膝体神经元的光反应,在共同作用时存在联合效应,主要表现为协同效应。     

石蒜科药用植物生物碱的药理学研究

石蒜科药用植物主要含生物碱成分,具有广泛的药理活性.参阅近十多年来国内外石蒜科生物碱化学成分及药理学的研究文献,对石蒜科植物生物碱的几种主要药理活性进行归纳.石蒜科植物生物碱药理作用主要包括对心血管系统作用、中枢神经系统作用、对多种癌细胞的细胞毒活性或抗肿瘤作用、抗炎抗菌、抗病毒、免疫功能等方面.石蒜科药用植物生物碱有着潜在而广泛的药用价值.