Using Water Bears to Investigate Adaptations to Extreme Stresses

某些动物可以在超出纯化的DNA、蛋白质和膜通常降解的环境极端条件下生存;这表明存在保护和/或快速修复多种细胞组分的机制。已经确定了一些保护剂，但尽管引起了广泛的兴趣，但通常还没有很好地理解可以使动物在这种极端条件下生存的机制。这项工作的长期目标是帮助理解动物和动物组织在极端条件下生存的机制。该项目使用缓步动物来解决这个问题，缓步动物是一种微观的，8条腿的无脊椎动物，可以在一系列极端环境中生存：多年的干燥，电离辐射是人类可以生存的1000倍，温度从低于1开尔文到超过150摄氏度，以及极端压力，甚至包括太空真空。该项目还涉及几项有可能产生更广泛影响的努力，包括为儿童和教师制作教材，为博物馆展览和活动做出贡献，为电视和印刷记者提供图像和视频，并为教科书提供图像和视频，以及与寻求利用这一新兴模式系统的其他科学家分享新开发的方法。缓步动物和其他生物通过从包括细菌在内的其他生物的水平基因转移获得某些基因。最近的研究揭示了某些水平转移的基因在缓步动物在某些极端条件下生存能力中的作用。该项目将通过研究一组水平转移基因的功能作用，更彻底地确定有助于极端条件下生存的机制，这些基因的表达是由环境极端诱导的。某些外源基因的产物可以在极端条件下执行关键的生化功能的假设将被测试，这些基因进入缓步动物基因组的机制将被调查。通过该项目共享的方法包括实验室培养方法，检查缓步动物基因表达和破坏基因功能的方法，以及在研究过程中新开发的方法。从长远来看，该项目的研究及其使其他科学家更容易研究缓步动物的努力可能有助于为生物材料保护剂的开发提供新的途径。

Certain animals can survive environmental extremes that are beyond those at which purified DNA, protein, and membranes typically degrade; suggesting that mechanisms exist that protect and/or rapidly repair multiple cellular components. Some protectants have been identified, but the mechanisms that can allow animals to survive such extremes are in general not yet well understood, despite being of wide interest. The long-term goal of this work is to contribute to understanding the mechanisms by which animals and animal tissues can survive extremes. This project addresses this issue using tardigrades, which are microscopic, 8-legged invertebrates that can survive a remarkable range of environmental extremes: desiccation for years, ionizing radiation 1000 times what humans can survive, temperatures from below 1 degree Kelvin to more than 150 degrees Celsius, and extremes of pressure including even the vacuum of space. The project also involves several efforts with potential to have broader impacts, including making educational materials for children and teachers, contributing to museum exhibits and events, providing images and videos to television and print journalists and for textbooks, and sharing of newly developed methods with other scientists seeking to make use of this emerging model system. Tardigrades and other organisms have acquired certain genes by horizontal gene transfer from other organisms including bacteria. Recent studies have revealed the roles of certain horizontally transferred genes in the ability of tardigrades to survive some extreme conditions. This project will more thoroughly identify mechanisms that contribute to survival of extreme conditions by examining functional roles for a set of horizontally transferred genes whose expression is induced by an environmental extreme. The hypothesis that products of certain foreign genes can perform key biochemical functions under extreme conditions will be tested, and the mechanisms by which these genes entered tardigrade genomes will be investigated. Methods to be shared through this project include lab culture methods, methods for examining tardigrade gene expression and disrupting gene functions, and methods newly developed in the course of the research. The research in this project and its efforts to make tardigrades easier for other scientists to study may contribute, in the long run, toward suggesting new avenues for the development of protectants for biomaterials.