Understanding molecular mechanisms associated with exposure to low and ultra low doses of ionizing radiation.

这个发现补助金更新申请是一个正在进行的计划的一部分，调查细胞对低剂量电离辐射暴露的反应机制。该提案的具体目标是，通过有选择地消除各种类型的自然本底辐射（宇宙射线、氡中的α射线和地球外部伽马光子），重点关注细胞对超低辐射剂量水平的反应机制。 利用我们实验室中建立的现代生物学终点，我们将试图理解自然背景辐射对生命至关重要的概念。在没有自然背景辐射和随之而来的自由基应激的情况下，我们假设细胞系统可能会动摇。电离辐射来自自然（宇宙和陆地）和人为（医学和能源）来源。 生物体可能会受到低剂量的自然和人为辐射源的照射，因此更好地了解与低剂量照射有关的生物机制是很有价值的。 众所周知，高剂量的电离辐射会产生活性氧和氧化应激，这可能会对细胞造成损害。 然而，在低剂量下，辐射可以诱导进化保守的适应性反应，其可以通过维持和激活细胞防御机制来保护细胞。 人类正准备在2024年重返月球，然后前往火星。在太空中，银河宇宙辐射是电离辐射，对生物生命造成损害，例如宇航员。我们正在与美国航天局的科学家合作开展几个项目，旨在了解空间辐射照射的后果以及保护生物体免受损害的可能对策。其中一个项目是BioSentinel，这是美国航天局艾姆斯研究中心天体生物学研究项目，旨在探测和测量深空辐射对生物体的影响。BioSentinel项目目前正在利用酵母酿酒酵母的转基因突变体作为生物传感器模型，研究深空（40，000，000公里）银河宇宙辐射对DNA损伤和修复的影响。目前，我们正在地球表面的实验室和地下2公里（6，800英尺）的新生命科学SNOLAB研究实验室中表征BioSentinel模型酵母菌株。 斯诺实验室上方的岩石负担几乎消除了所有的银河宇宙辐射。 SNOLAB内的专门屏蔽消除了从岩壁发出的外部地面伽马辐射，创新的生长室消除了自然产生的放射性氡气。 因此，我们可以检验背景辐射调节生物过程并可能是生命的重要组成部分的假设。 这项研究将帮助我们了解一些生物过程如何在太空旅行时保护人类和其他生命形式免受银河宇宙辐射的影响。

This Discovery Grant renewal application is part of an ongoing program investigating mechanisms of cellular responses to low doses of ionizing radiation exposure. This proposal has the specific aim to focus on cellular response mechanisms to levels of ultra-low radiation doses by selectively removing various radiation types of natural background radiation (cosmic rays, alpha from radon, and terrestrial external gamma photons). Using modern biological endpoints well established in our laboratory, we will seek to understand the notion that natural background radiation is essential for life. In the absence of natural background radiation and consequent free radical stress, we hypothesize that cellular systems may falter. Ionizing radiation comes from natural (cosmic and terrestrial) and manmade (medicine and energy) sources. Living organisms may be exposed to low doses of natural and manmade sources and a better understanding of the biological mechanisms associated with low dose exposures is valuable. It is well known that high doses of ionizing radiation produce reactive oxygen species and oxidative stress which can be damaging to cells. However, at low doses, radiation can induce an evolutionary conserved adaptive response that may protect cells by maintaining and activating cellular defense mechanisms. Humans are preparing to return to the moon in 2024 and then onward to Mars. In space, galactic cosmic radiation is ionizing radiation which causes damage to biological life, e.g. astronauts. We are collaborating NASA scientists on several projects aimed at understanding the consequences of space radiation exposure and possible countermeasures to protect organisms from the damage. One of the projects is BioSentinel which is a NASA Ames Research Center astrobiology research project that aims to detect and measure the impact of deep space radiation on living organisms. The BioSentinel project is currently utilizing genetically modified mutants of the yeast Saccharomyces cerevisiae as a biosensor model to study the effects of galactic cosmic radiation in deep space (40,000,000 km) on DNA damage and repair. Currently, we are characterizing the BioSentinel model yeast strains in our lab on the earth surface and in our new novel life sciences SNOLAB research laboratory 2km (6,800 ft) underground. The rock burden above SNOLAB eliminates virtually all galactic cosmic radiation. Specialized shielding within the SNOLAB eliminates external terrestrial gamma radiation emanating from the rock walls, and an innovative growth chamber eliminates naturally occurring radioactive radon gas. Consequently, we can test the hypothesis that background radiation modulates biological processes and may be an essential component of life. The research will help us understand how some biological processes may be critical to protect humans and other life forms from galactic cosmic radiation while travelling in space.