Nitrogen excretion and acid-base regulation in invertebrate systems: Mechanisms, regulation and the specific role of Rh-proteins and AMTs.

无脊椎动物系统中的氮排泄和酸碱调节：Rh 蛋白和 AMT 的机制、调节和具体作用。

• 批准号: 355891-2013
• 负责人: Weihrauch, Dirk
• 金额: $ 2.4万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=527944
• 关键词: Nitrogen; excretion; acid; base; regulation

Ammonia is a highly toxic waste product derived from protein metabolism. In ammoniotelic animals (e.g. aquatic invertebrates and fish), where ammonia is excreted directly and not transformed into less toxic molecules such as urea or uric acid, an effective excretion system is essential to keep cellular and body fluid ammonia levels within a tolerable range. Although ca. 98% (= 30 phyla) of all animals are invertebrates, our knowledge of nitrogen excretion strategies and mechanisms in this dominant group is rather diminutive. The goal of the proposed research is to gain first and detailed insights of ammonia excretion pathways and mechanisms in a wide variety of different invertebrate groups, including annelids (freshwater leeches), nematodes (soil living roundworms), mollusks (freshwater mussels), arachnids (seawater horseshoe crabs) and crustaceans (fresh-, brackish-, and seawater crabs). The proposed research consists of three main objectives, investigating: (1) the actual excretion mechanisms in aquatic invertebrates to explore common ancestral excretion strategies; (2) the evolution and function of the phylogenetic ancient bacterial and plant "AMTs" and the distantly related animal "Rh-proteins" in the soil nematode Caenorhabditis elegans, a transitional animal that expresses both types of ammonia transporters; (3) the relation of ammonia excretion and acid-base balance in crustaceans and the effects of predicted increases in global aquatic pCO2 levels and ocean acidification on the pH-regulation in euryhaline crabs. The three objectives will provide novel insights of the evolution of ammonia excretion mechanisms and acid-base regulation in phylogentic ancient invertebrates, including the roles of Rh-proteins and AMTs as NH3, CO2 or H+ -channels. It is expected that fundamental and general nitrogen excretion and pH regulatory strategies will be discovered. Understanding the ammonia excretion mechanisms as well as the animal's responses towards elevated environmental ammonia levels are crucial for conservation programs, which are intended to protect animal communities living in aquatic habitats threatened by ammonia-rich agricultural run-off and also to manage aquaculture facilities.

氨是源自蛋白质代谢的剧毒废物。在氨的动物（例如水生无脊椎动物和鱼类）中，其中氨被直接排泄，而不会转化为尿素或尿酸等毒性较小的分子，有效的排泄系统对于将细胞和体液氨水保持在容忍的范围内至关重要。虽然CA。所有动物的98％（= 30个门）都是无脊椎动物，我们对这一主导群体中氮的排泄策略和机制的了解相当小。拟议的研究的目的是获得各种不同不同无脊椎动物的氨排泄途径和机制的第一和详细见解，包括annelids（淡水水ech），线虫（土壤活圆虫），Mollusks（Mollusks）（Mollusks（Mollusks）（淡水缪斯女神），Arachnids（Arachnids）海水马蹄蟹）和甲壳类动物（新鲜，咸水和海水蟹）。拟议的研究由三个主要目标组成：（1）水生无脊椎动物中的实际排泄机制探讨了共同的祖先排泄策略； （2）系统发育古代细菌和植物“ AMTS”的演化和功能以及土壤线虫线虫Caenorhabditis elegrans elegans exemans exemans and amts and植物“ AMT”和远距离相关的动物“ Rh蛋白”，这是一种过渡性动物，表达了两种类型的氨转运蛋白； （3）甲壳类动物中氨排泄和酸碱平衡的关系，以及预测的全球水生PCO2水平增加的影响以及海洋酸化对euryhaline螃蟹pH调节的影响。这三个目标将提供有关氨排泄机制进化的新见解，以及酸碱古代无脊椎动物中的酸碱调节，包括rh蛋白和AMTS作为NH3，CO2或H+频道的作用。预计将发现基本和一般的氮排泄和pH调节策略。了解氨排泄机制以及动物对升高环境氨水的反应对于保护计划至关重要，保护计划旨在保护生活在富含氨的农业径流威胁的水生栖息地和水产养殖设施中。