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首页> 外文期刊>Integrative and Comparative Biology >Implications of dealing with airborne substances and reactive oxygen species: what mammalian lungs, animals, and plants have to say
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Implications of dealing with airborne substances and reactive oxygen species: what mammalian lungs, animals, and plants have to say

机译：处理空气中的物质和活性氧的含义：哺乳动物的肺，动植物必须说些什么

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A gas-exchange structure interacts with the environment and is constantly challenged by contaminants thatmay elicit defense responses, thus compromising its primary function. It is also exposed to high concentrations of O_2 thatcan generate reactive oxygen species (ROS). Revisiting the lung of mammals, an integrative picture emerges, indicatingthat this bronchi-alveolar structure deals with inflammation in a special way, which minimizes compromising the gas-exchange role. Depending on the challenge, pro-inflammatory or antiinflammatory responses are elicited by conservedmolecules, such as surfactant proteins A and D. An even broader picture points to the participation of airway sensors,responsive to inflammatory mediators, in a loop linking the immunological and nervous systems and expanding the roleplayed by respiratory organs in functions other than gas-exchange. A byproduct of exposure to high concentration ofO_2 is the formation of superoxide (O_2~-), hydrogen peroxide (H_2O_2), hydroxyl radical (HO), and other ROS, which areknown to be toxic to different types of cells, including the lung epithelium. A balance between antioxidants and oxidantsexists; in pulmonary epithelial cells high intracellular and extracellular levels of antioxidants are found. Antioxidantadaptations related to plant and animal life-styles involve a broad range of overlapping strategies based on well-conservedmolecules. Glutathione (GSH) is an abundant and ubiquitous thiol-tripeptide antioxidant, also present in lungs, whoserole in providing information on the intracellular redox state of animals and plants is well established. In these organisms,GSH influences gene expression associated with stress, maximizing defense responses. Several enzymatic antioxidants,such as glutathione peroxidase (GPx), glutathione reductase, glutathione S-transferase, and glucose 6-phosphatedehydrogenase participate in the redox system; in animals that are stress-tolerant GPx is a key element against oxidativeassaults. Most importantly, alternative roles of ROS as signaling molecules have been found in all plants and animals.For example, alveolar macrophages produce O_2~- that act as second messengers, in addition to having a bactericidal role.The nonradical ROS H_2O_2 signals inflammation in mammalian lungs, apoptosis in different animal tissues, and is alsoinvolved in stomatal closure, root development, gene expression, and defense responses of plants. Antioxidant adaptationsin some water-breathing animals involve the excretion of H_2O_2 by diffusion through gas-exchange structures. The finebalance among a multitude of factors and cells makes the difference between damage and protection in animals andplants. Knowledge about the mechanisms and consequences of these molecular interactions is now starting to beintegrated.
机译：气体交换结构与环境相互作用，并不断受到可能引起防御反应的污染物的挑战，从而损害了其主要功能。它还暴露于高浓度的O_2中，这些O_2可能产生活性氧（ROS）。重新审视哺乳动物的肺部时，出现了一张完整的图片，表明该支气管-肺泡结构以特殊方式处理炎症，从而最小化了对气体交换作用的损害。根据挑战，通过保守分子（例如表面活性剂蛋白A和D）引发促炎或抗炎反应。更广泛的观点指向气道传感器对炎症介质的反应参与连接免疫系统和神经系统的循环中以及扩大呼吸器官在气体交换以外的功能中的作用。暴露于高浓度O_2的副产物是超氧化物（O_2〜-），过氧化氢（H_2O_2），羟基自由基（HO）和其他ROS的形成，已知这些氧化物对不同类型的细胞（包括肺上皮）有毒性。抗氧化剂和氧化剂之间保持平衡;在肺上皮细胞中，发现细胞内和细胞外的抗氧化剂水平高。与植物和动物的生活方式有关的抗氧化适应性改变涉及基于保守分子的广泛重叠策略。谷胱甘肽（GSH）是一种丰富且普遍存在的硫醇三肽抗氧化剂，也存在于肺中，其提供有关动植物细胞内氧化还原状态信息的作用已得到公认。在这些生物中，GSH影响与压力相关的基因表达，从而使防御反应最大化。几种酶促抗氧化剂，例如谷胱甘肽过氧化物酶（GPx），谷胱甘肽还原酶，谷胱甘肽S转移酶和葡萄糖6-磷酸脱氢酶参与了氧化还原系统。在耐压力的动物中，GPx是抵抗氧化攻击的关键因素。最重要的是，在所有动植物中都发现了ROS作为信号分子的替代作用，例如，肺泡巨噬细胞除具有杀菌作用外还产生O_2〜-充当第二信使。非自由基的ROS H_2O_2可以在哺乳动物体内发出炎症信号。肺，不同动物组织中的细胞凋亡，还参与气孔关闭，根发育，基因表达和植物的防御反应。在一些呼吸动物中，抗氧化剂的适应性涉及通过气体交换结构的扩散来排泄H_2O_2。多种因素和细胞之间的细微平衡使动植物受到的损害与保护有所不同。关于这些分子相互作用的机理和后果的知识现在开始被整合。

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