Metabolic pathway

代谢途径
  • 文章类型: Journal Article
    由于持久性和剧毒污染物,从接收再生水的河流长期渗透将对渗流带和地下水构成潜在风险。为了预测生态和健康风险的时空分布,提出了HYDRUS-GMS组合风险商的耦合模型。该模型能准确预测水流,由于可接受的效率,模型中的溶质运输和风险(E:0.99),平均绝对误差(MAE:0.031m)和均方根误差(RMSE:0.039m)。galaxolide(HHCB)的含量,一种典型的药物和个人护理产品,具有疏水性,在再生水中难熔,随着浸润时间的延长,渗流带以6.1ngg-1year-1的累积速率增加。53年渗入渗出后的积聚将构成生态风险。一旦穿透渗流带,潜在的风险将扩大到地下水,主要沿地下水流向扩散。由于三个方向的驱动力的变化,沿地下水流水平方向的迁移速率为0.03396md-1,是纵向和垂直速率的9.7和1.1倍。由于疏水性,HHCB的迁移率为地下水流量的2.6%(LogKow=5.9)。HHCB的完全生化分解将需要大约0.38年的时间通过182.65m距离内的代谢物。持久性归因于高慢性毒性和低生物利用度。HHCB的主要生化代谢是酶水解,环开口,脱羧,在182.65m迁移距离后约0.38年内分解和碳化。本研究为中水回用风险时空分布预测提供了一种新方法。
    Long-term infiltration from river receiving reclaimed water will pose potential risk to vadose zone and groundwater because of the persistent and highly toxic contaminants. In order to predict the spatio-temporal distribution of ecological and health risk, a coupled model of HYDRUS-GMS combined risk quotient was proposed. The model can accurately predict water flow, solute transport and risk with model due to the acceptable efficiency (E:0.99), mean absolute error (MAE:0.031 m) and root-mean-square error (RMSE:0.039 m). The content of galaxolide (HHCB), a typical pharmaceutical and personal care product with hydrophobicity and refractory in reclaimed water, increased in vadose zone at an accumulative rate of 6.1 ng g-1 year-1 with infiltration time extension. The accumulation will pose ecological risk after 53 years infiltration. The potential risk will extent to groundwater once penetrate through vadose zone, and mainly diffuse along groundwater flow direction. The migration rate along horizontal direction of groundwater flow is 0.03396 m d-1, which is 9.7 and 1.1 times higher than longitudinal and vertical rates due to the variation of driving force in three directions. The migration rate of HHCB was 2.6% of groundwater flow due to hydrophobicity (LogKow = 5.9). The complete biochemical decomposition of HHCB will take approximately 0.38 year through metabolite within 182.65 m distance. The persistence was attributed to the high chronic toxicity and the low bio-availability. The major biochemical metabolism of HHCB was enzymatic hydrolysis, ring opening, decarboxylation, which was decomposed and carbonized within approximately 0.38 year after 182.65 m migration distance. This study provided a new approach to predict the spatio-temporal risk distribution due to reclaimed water reuse.
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  • 文章类型: Journal Article
    次级代谢产物,也被称为植物化学物质,代表植物分子的一大子集,包括具有促进健康作用的化合物。的确,许多流行病学研究表明,当定期服用并以足够的数量服用时,这些分子可以对人类健康产生长期有益的影响,通过减少退行性疾病的发病率,比如心血管疾病,肥胖,糖尿病,和癌症。由于这些植物化学物质的饮食摄入量往往不足,正在使用各种策略来提高其在主要作物中的含量,及其最终产品。最有效的策略之一是通过遗传方法改良作物,因为这是产生新品种的唯一方法,其中给定的植物化学物质的高积累是稳定固定的。基因改善品质性状的努力正在迅速发展,从经典育种到分子辅助方法;这些需要对性状的分子基础有充分的了解,确定控制它们的基因/等位基因。这可以通过对负责植物化学物质积累的代谢途径的整体分析来实现,确定植物化学物质含量与调节代谢途径的关键酶活性之间的联系,以及关键酶及其编码基因/等位基因之间。一旦这些被识别出来,它们可以用作通过生物技术方法选择新的改良基因型的标记。这篇综述概述了与植物化学物质的饮食摄入有关的主要健康促进特性,并描述了分子方法如何为改善食用作物的健康质量提供手段。最后,举例说明了一个案例研究,在硬粒小麦中鉴定出控制粗面粉食品中最终类胡萝卜素含量的脂氧合酶-B1基因,如面食产品。
    Secondary metabolites, also known as phytochemicals, represent a large subset of plant molecules that include compounds with health-promoting effects. Indeed, a number of epidemiological studies have shown that, when taken regularly and in adequate amounts, these molecules can have long-term beneficial effects on human health, through reduction of the incidence of degenerative diseases, such as cardiovascular diseases, obesity, diabetes, and cancer. As the dietary intake of these phytochemicals is often inadequate, various strategies are in use to improve their content in staple crops, and the end-products thereof. One of the most effective strategies is crop improvement through genetic approaches, as this is the only way to generate new cultivars in which the high accumulation of a given phytochemical is stably fixed. Efforts to genetically improve quality traits are rapidly evolving, from classical breeding to molecular-assisted approaches; these require sound understanding of the molecular bases underlying the traits, to identify the genes/alleles that control them. This can be achieved through global analysis of the metabolic pathway responsible for phytochemical accumulation, to identify the link between phytochemical content and the activities of key enzymes that regulate the metabolic pathway, and between the key enzymes and their encoding genes/alleles. Once these have been identified, they can be used as markers for selection of new improved genotypes through biotechnological approaches. This review provides an overview of the major health-promoting properties shown to be associated with the dietary intake of phytochemicals, and describes how molecular approaches provide means for improving the health quality of edible crops. Finally, a case study is illustrated, of the identification in durum wheat of the Lipoxygenase-B1 genes that control the final carotenoid content in semolina-based foods, such as pasta products.
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