Knowledge Resource Center for Ecological Environment in Arid Area
| 长爪沙鼠（Meriones unguiculatus）水代谢生理特征的季节变化和地理差异：尿液渗透压和肾脏水通道蛋白（AQPs） | |
| 其他题名 | Seasonal and geographical variation in water metabolism of Mongolian gerbils (Meriones unguiculatus): urine osmolality and renal aquaporins (AQPs) |
| 徐萌萌 | |
| 出版年 | 2016 |
| 学位类型 | 博士 |
| 导师 | 王德华 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 长爪沙鼠（Meriones unguiculatus）广泛分布于俄罗斯外贝加尔、蒙古和中国北部的荒漠、荒漠草原、典型草原区及其毗邻的农牧交错地带。其分布区环境及气候条件季相变化明显，且年降水总量自东向西显著减少。因此，水分可利用性在时间和空间上的局限性对长爪沙鼠生存和繁殖是很大的挑战。然而，动物在水代谢生理方面应对环境气候时空变化的机理（如肾脏的节水机理等）尚乏研究。本论文整合形态学、生理学以及分子学的方法，通过比较不同季节、不同地理区域以及室内禁水操控条件下长爪沙鼠水代谢响应特征，旨在揭示长爪沙鼠的水代谢表型可塑性和分子适应机理。主要结果和结论如下： 1.为探明长爪沙鼠水代谢生理特征的季节变化模式，我们检测了野外春、夏和秋季长爪沙鼠水代谢生理指标的变化以及相应季节植物水、氮和脂肪含量的变化。结果发现长爪沙鼠成体体重没有明显的季节差异，长爪沙鼠的肾脏重量春季显著大于夏秋季，肾脏相对髓质厚度（Relative medullary thickness; RMT）和尿液渗透压则春季显著小于夏秋季。血清抗利尿激素浓度春夏季显著低于秋季。三个季节中肾脏AQPs的表达量没有差异。夏秋季植物的水、氮和脂肪含量相对较高，植物的水含量同肾脏重量，氮和脂肪含量同肾脏RMT均显著正相关。结果表明长爪沙鼠利用肾脏形态和渗透调节的弹性变化适应不同季节环境的差异。 2.为了解不同栖息地的长爪沙鼠是否存在水代谢生理的变化，我们比较了内蒙古地区典型草原、荒漠草原和荒漠3种生境内长爪沙鼠的水代谢生理指标以及相应生境内植物水分、氮和脂肪含量的变化。结果发现3种生境内长爪沙鼠的体重、肾脏重量、肾脏相对髓质厚度、血清渗透压、血清抗利尿激素以及肾脏AQPs的表达量均没有显著差异。不同栖息地植物水分含量没有显著差异，氮含量荒漠区和荒漠草原区显著大于典型草原区，脂肪含量荒漠区显著小于典型草原区。结果表明，沿不同地理梯度，长爪沙鼠保持稳定的水代谢生理特征。 3. 为进一步理解长爪沙鼠对极端干旱条件的耐受能力，我们在实验室条件下检测了禁水7天的长爪沙鼠尿液渗透压和肾脏AQPs分布和表达。发现长爪沙鼠禁水7天的平均尿液渗透压为7503 mOsm kg? 1，比基础状态（4222 mOsm kg? 1）高77.7%。肾脏AQP1、AQP2、AQP3的分布和已报导的其他啮齿类相似。禁水7天后，肾脏AQP2表达显著增多，静止代谢率和总蒸发失水分别降低了43%和36%。结果表明长爪沙鼠能够运用较强的尿液浓缩能力、肾脏AQPs表达的调节和体水节约策略应对极端缺水环境。 我们的研究结果表明面临不同季节环境的变化时，长爪沙鼠在肾脏形态和渗透调节方面具有弹性的水代谢生理特征。不同地理分布区的长爪沙鼠肾脏形态和生理特征没有显著差异，显示出稳定的肾脏节水特点。而实验室极端缺水条件下，长爪沙鼠肾脏重量和RMT没有改变，在粪尿失水和蒸发失水方面表现出了高效的节水效率，同时肾脏AQP2表达的蛋白水平也显著增加。综上所述，长爪沙鼠针对不同环境表现出不同的水代谢适应策略，可能是长期进化和短期适应调节综合作用的结果，水代谢适应策略的改变可能对其野外生存和繁殖很关键。 |
| 英文摘要 | Mongolian gerbils (Meriones unguiculatus) are widely distributed in deserts, desert steppe, typical steppe and the transition zone between grasslands and farmlands in Inner Mongolian of China, the Baikal region of Russia, and Mongolia. The habitats are characterized by extreme seasonal environment and ambient temperature fluctuations, and the precipitation significantly decreases from east to west along the large-scale distribution. Thus the limited spatial and temporal availability of free water is a great challenge for their survival and reproduction. However, there has been little investigation into the adaptational mechanism of water metabolism in animals (such as the water conservation mechanism of kidney) to the spatial and temporal variation of climate. Here, we compared the water metabolism of 3 different seasons and geographic gradient and the laboratory water deprivation (WD) experiment in Mongolian gerbils by integrating morphological, physiological, and cellular levels of different parameters, aim to encompass the phenotypic flexibility of water metabolism and the molecular adaptive mechanism. The main results and conclusions are as follows: 1. In order to understand the seasonal variation of phenotypic flexibility in water metabolism of Mongolian gerbils, we examined the physiological parameters of water metabolism in mongolian gerbils and the water, nitrogen and fat content in plants among spring, summer, and autumn. Results show that gerbils form the 3 seasons possess similar body mass, but remarkably different kidney mass, relative medullary thickness (RMT), urine osmolality, and serum vasopressin concentration. However, the expressions of renal AQPs stay unaltered among the 3 seasons. What’s more, the plants in summer and autumn possess more abundant water nitrogen, and fat. There is positive correlations between water content in plant and kidney mass, nitrogen and fat content in plant with renal relative medullary thickness (RMT). Our results demonstrate that Mongolian gerbils show phenotypic flexibility in renal morphology and osmoregulation to cope with seasonal variations in environment. 2. To understand whether there is geographic variation in physiological flexibility in water metabolism of Mongolian gerbils, we compared the physiological parameters of water metabolism in Mongolian gerbils and the water, nitrogen, and fat content in plants among east New Barag typical steppe, middle Sonid desert steppe, and west Alxa desert. Results show that Mongolian gerbils form the 3 habitats possess similar body mass, kidney mass, renal medulla thickness (RMT), serum osmolality, vasopressin concentration, and renal expression of AQPs. What’s more, the plants in west Alxa desert possess more abundant nitrogen, but less abundant water and fat (which could produce large amunt of metabolic water). Our results demonstrate that Mongolian gerbils show stable physiological characteristics in water metabolism along geographic gradient. 3. To better understand how desert rodents adapt to extreme water scarcity, we examined urine osmolality, renal distribution and expression of aquaporins (AQPs) in Mongolian gerbils during 7 days of WD under laboratory condition. Results show that urine osmolality of the gerbils during WD averaged 7503 mosm kg-1, which is 77.7 % higher than the control conditions (4222 mosm kg-1). Renal distributions of AQP1, AQP2, and AQP3 were similar to that described in other rodents. After the 7 day WD, renal AQP2 was remarkably up-regulated, while resting metabolic rate and total evaporative water loss decreased by 43% and 36%, respectively. Our data demonstrated that Mongolian gerbils showed high urine concentration, renal AQPs expression and body water conservation to cope with extreme water scarcity. Our results demonstrated that when faced by seasonal variations in environment, Mongolian gerbils show phenotypic flexibility of renal morphology and osmoregulation. However, there are no variations in renal morphology and physiology in Mongolian gerbils among the 3 habitats; they show stable physiological characteristics in water metabolism. However, when faced by extreme water scarcity, Mongolian gerbils don’t alter the kidney mass and RMT, but show high efficiency in urinal, fecal and evaporative water loss, and upregulate renal AQP2 protein abundance remarkably. In conclusion, Mongolian gerbils show different adaptive strategy in water metabolism to cope with different environment, this may due to the interaction of long-time evolution and short-time acclimation, the difference in adaptive strategy in water metabolism may be critical for their survival and reproduction in the wild. |
| 中文关键词 | 长爪沙鼠 ; 水代谢 ; 水通道蛋白 ; 干旱适应 |
| 英文关键词 | Mongolian gerbils (Meriones unguiculatus) water metabolism aquaporins aridty adaptation |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院动物研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287673 |
| 推荐引用方式 GB/T 7714 | 徐萌萌. 长爪沙鼠（Meriones unguiculatus）水代谢生理特征的季节变化和地理差异：尿液渗透压和肾脏水通道蛋白（AQPs）[D]. 中国科学院大学,2016. |
| 条目包含的文件 | 条目无相关文件。 | |||||
| 个性服务 |
| 推荐该条目 |
| 保存到收藏夹 |
| 导出为Endnote文件 |
| 谷歌学术 |
| 谷歌学术中相似的文章 |
| [徐萌萌]的文章 |
| 百度学术 |
| 百度学术中相似的文章 |
| [徐萌萌]的文章 |
| 必应学术 |
| 必应学术中相似的文章 |
| [徐萌萌]的文章 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
