Synchrotron studies of selenium environmental chemistry

硒环境化学的同步加速器研究

• 批准号: RGPIN-2016-05810
• 负责人: Pickering, Ingrid
• 金额: $ 4.44万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=691077
• 关键词: Synchrotron; studies; selenium; environmental; chemistry

Selenium in the environment. As a micronutrient element required for all kingdoms of life, selenium (Se) is one of the least abundant micronutrients in the earth's crust. World Se distribution is highly variable; while Canada's prairie soils are among the richest yielding higher Se crops, globally soils are more likely to provide inadequate Se. Moreover, Se has a smaller difference between sufficient and excess dietary amounts than perhaps any other element. There is growing concern over slightly elevated Se in aqueous environments in several areas of Canada due to mining or other anthropogenic activities, since bioaccumulation of Se can cause problems for top predators. This delicate balance between insufficient and excess is just one challenge of Se.****Selenium in organisms. The twenty-first amino acid selenocysteine occurs in active sites of key enzymes such as glutathione peroxidase. In addition Se has enigmatic biological interactions with toxic elements including mercury, arsenic and cadmium. While some Se chemical forms can protect against such elements, in other scenarios Se can increase toxicity. Although the former is at least partly understood, the latter mechanisms remain a mystery. ******Objectives. The program seeks a holistic view of the roles and interactions of Se at the molecular level both in the environment and in impacting human health. Knowing the chemical form of Se is key to understanding its function and impact, whether detrimental, benign or beneficial. ******Scientific approach. Building upon career contributions, the program will use and develop synchrotron techniques, sharing refinements with the research community especially at the Canadian Light Source BioXAS beamlines where the applicant is scientific co-lead. X-ray absorption spectroscopy provides speciation information while X-ray fluorescence imaging yields microscopic elemental distributions in biological samples with little pretreatment. Studies will include structural characterization of purified biomolecules to determine Se functions. Other projects will address Se distribution, chemical forms and interactions with other elements in plants and animal models in order to understand underlying mechanisms.******Training. Highly qualified personnel trained through cross-disciplinary projects to use and develop specialized synchrotron tools will be more generally adept at adapting technologies to solve problems, positioning them for high profile careers.******Strategic relevance. High soil Se in Canada's prairies leads to crops rich in Se, potentially increasing their nutritional value. Conversely, slightly elevated Se in mining runoff can be environmentally problematic. Both positive and negative faces of Se have significant economic consequences. This work advances understanding of Se's contrasting roles in living organisms, essential in assessing both positive and negative aspects of Se in Canada. **

环境中的硒。作为所有生命王国所需的微量营养元素，硒（Se）是地壳中最丰富的微量营养元素之一。世界硒分布变化很大；虽然加拿大的草原土壤是最丰富的高硒作物之一，但全球土壤更有可能提供不足的硒。此外，硒在充足膳食量和过量膳食量之间的差异可能比任何其他元素都要小。由于采矿或其他人为活动，加拿大一些地区的水环境中硒含量略有升高，人们越来越担心，因为硒的生物累积可能会给顶级捕食者带来问题。这种不足与过量之间的微妙平衡只是有机体中硒的挑战之一。****硒。第二十一个氨基酸硒代半胱氨酸存在于谷胱甘肽过氧化物酶等关键酶的活性位点。此外，硒与汞、砷和镉等有毒元素具有神秘的生物相互作用。虽然某些硒的化学形式可以防止这些元素的侵害，但在其他情况下，硒会增加毒性。尽管前者至少被部分了解，但后者的机制仍然是个谜。 ******目标。该项目寻求在分子水平上全面了解硒在环境和影响人类健康方面的作用和相互作用。了解硒的化学形式是了解其功能和影响的关键，无论是有害的、良性的还是有益的。 ******科学的方法。在职业贡献的基础上，该项目将使用和开发同步加速器技术，与研究界分享改进成果，特别是在加拿大光源 BioXAS 光束线方面，申请人是该项目的科学联合领导者。 X 射线吸收光谱可提供形态信息，而 X 射线荧光成像只需很少的预处理即可产生生物样品中的微观元素分布。研究将包括纯化生物分子的结构表征以确定硒的功能。其他项目将解决硒的分布、化学形式以及与植物和动物模型中其他元素的相互作用，以了解潜在的机制。*****培训。通过跨学科项目培训使用和开发专用同步加速器工具的高素质人才将更善于利用​​技术来解决问题，从而将他们定位于高调的职业生涯。******战略相关性。加拿大大草原土壤含硒量高，农作物富含硒，有可能增加其营养价值。相反，采矿径流中硒的轻微升高可能会造成环境问题。硒的正面和负面面都会产生重大的经济后果。这项工作增进了对硒在生物体中不同作用的理解，这对于评估加拿大硒的积极和消极方面至关重要。 **