Diapause, Stress Tolerance and Molecular Chaperones in Artemia franciscana

卤虫的滞育、胁迫耐受性和分子伴侣

• 批准号: RGPIN-2016-04882
• 负责人: Macrae, Thomas
• 金额: $ 3.93万
• 依托单位: Dalhousie University
• 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=690448
• 关键词: Diapause; Stress; Tolerance; Molecular; Chaperones

Embryos of the crustacean, Artemia franciscana, develop into swimming larvae or they encyst and enter diapause, a physiological state characterized by developmental arrest and greatly reduced metabolism. Encysted embryos (cysts) are very stress tolerant, surviving extreme temperature, desiccation and years without oxygen when hydrated at ambient temperature. A. franciscana cysts therefore represent one of the most stress tolerant multicellular life forms on Earth. A. franciscana embryos exhibit differential gene regulation during diapause-destined development, producing proteins required for the initiation, maintenance and termination of diapause, with maintenance the period of greatest stress tolerance. The global objectives of the proposed research are to elucidate cell, molecular and biochemical mechanisms by which A. franciscana regulate diapause-specific development and determine how embryos survive severe physiological stress. Heat shock factor 1 (HSF1) which normally activates genes expressed during physiological stress will be tested to determine if it regulates gene expression during diapause. Of particular interest is an abundant, diapause-specific molecular chaperone, p26, which functions in the absence of an energy supply. p26 is thought to bind denaturing proteins in diapause embryos and protect them from irreversible denaturation. Consequently, substrate proteins of p26 will be identified. Several molecular chaperones such as Hsp40, Hsp70 and Hsp90 require energy for activity. The synthesis of these proteins will be investigated during diapause-destined embryo development, as will their protective function when energy is limiting, as occurs in diapause. Proteins that regulate diapause termination will also be identified. Thus, a central question addressed by the proposed research is how embryos of A. franciscana survive severe stressors which kill most other organisms rather quickly. Are molecular chaperones responsible for stress tolerance and, if so, how do they contribute to this process? Answering these questions will provide significant fundamental insights into diapause and the functions of essential cellular proteins such as the molecular chaperones. On an applied level, the proposed research may facilitate the use of A. franciscana in aquaculture where the organism is used to feed the larvae of commercially important fish and aquatic invertebrates. Hsp70, for example, plays a role in the resistance of A. franciscana to bacterial infection, indicating that the proposed work will lead to improvements in the culture of A. franciscana. Moreover, a better understanding of diapause has consequences for agriculture, forestry and medicine as it may allow for the development of methods for the control of insect pests able to survive winter and attempts at their eradication when in diapause, this of direct benefit to Canada.

甲壳类动物的胚胎阿尔emia franciscana的胚胎发展成游泳幼虫，或者它们被开除并进入抑郁，这是一种以发育停滞和大幅度降低代谢为特征的生理状态。在环境温度下水合时，环保胚胎（囊肿）具有非常耐应的胁迫性，过度温度，干燥和不氧。因此，方济各会囊肿代表了地球上最耐心的多细胞生命形式之一。弗朗西斯卡菌胚胎在滞育的发育过程中表现出差异基因调节，从而产生育开始，维持和终止所需的蛋白质，并维持最大的胁迫耐受性。拟议的研究的全球目标是阐明细胞，分子和生化机制，通过这些机制，franciscana调节糖尿病特异性发育并确定胚胎如何在严重的生理压力下存活。热休克因子1（HSF1）通常会激活在生理胁​​迫期间表达的基因，以确定其在滞育过程中是否调节基因表达。特别令人感兴趣的是丰富的二糖尿病特异性分子伴侣P26，它在没有能量供应的情况下起作用。 p26被认为可以结合延迟胚胎中的蛋白质，并保护它们免受不可逆的变性。因此，将确定p26的底物蛋白。 HSP40，HSP70和HSP90等几个分子伴侣需要活性的能量。这些蛋白质的合成将在滞育二固定的胚胎发育过程中进行研究，当能量限制时它们的保护功能也将如滞育一样。调节滞育终止的蛋白质也将被识别。因此，拟议的研究提出的一个核心问题是，弗朗西斯果曲霉的胚胎如何在严重的压力源中幸存下来，这些压力源杀死大多数其他生物体。分子伴侣是否负责胁迫耐受性，如果是的，它们如何为这一过程做出贡献？回答这些问题将为滞育和必需细胞蛋白（例如分子伴侣）的功能提供重要的基本见解。在应用的水平上，拟议的研究可能有助于在水产养殖中使用坦曲霉，在这种水产养殖中，该生物被用来喂养商业重要的鱼类和水生无脊椎动物的幼虫。例如，HSP70在弗朗西斯田曲霉对细菌感染的抗性中发挥了作用，这表明拟议的工作将导致方念珠菌培养物的改善。此外，更好地理解滞育会对农业，林业和医学产生影响，因为这可能允许开发方法来控制能够生存的冬天生存的虫害，并在隔离时试图消除这种方法，这是对加拿大的直接利益。