Urea synthesis and excretion in Aedes aegypti mosquitoes are regulated by a unique cross-talk mechanism.
Urea synthesis and excretion in Aedes aegypti mosquitoes are regulated by a unique cross-talk mechanism.
复制标题
DOI：
10.1371/journal.pone.0065393
复制
发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Scaraffia PY
中科院分区：
文献类型：
--
作者：
Isoe J;Scaraffia PY
埃及伊蚊没有一个典型的功能性尿素循环氨处置，如一个存在于大多数陆生脊椎动物。然而，它们可以通过两种不同的途径合成尿素，即解胰蛋白酶和解尿酸。我们研究了这两种途径如何调节尿素的形成。埃及人。RNA干扰分别或同时抑制尿酸氧化酶（UO）和尿酸酶（AR）的表达。使用质谱法对排泄物中几种含氮化合物的量进行定量。用dsRNA-AR或dsRNA-UO注射蚊子显著降低脂肪体（FB）和马氏管（MT）中AR或UO的表达。令人惊讶的是，当UO沉默时，AR的表达水平增加，反之亦然，这表明通路之间的串扰调节。与这些数据一致，在注射dsRNA-AR或dsRNA-UO的那些蚊子中，在血液喂养后48小时测量的尿素量保持不变。然而，注射dsRNA-AR的雌性动物的排泄物中尿囊素显著增加。ARUO基因的敲低主要导致尿素和尿囊素排泄减少，精氨酸排泄增加。此外，用特异性一氧化氮合酶抑制剂处理的dsRNA-AR注射的蚊子显示出FB和MT中UO表达的增加以及含氮化合物排泄的显著增加。有趣的是，在注射dsRNA-AR、UO或ARUO的雌性动物中观察到血餐消化的暂时延迟和参与氨代谢的几种基因表达的显著降低。这些结果表明，尿素的合成和排泄在A。埃及人受到独特的串扰信号机制的严格调控。这一过程允许吸血蚊子调节氮废物的合成和/或排泄，并避免可能由其组织中致命浓度的氨引起的毒性作用。
Aedes aegypti mosquitoes do not have a typical functional urea cycle for ammonia disposal such as the one present in most terrestrial vertebrates. However, they can synthesize urea by two different pathways, argininolysis and uricolysis. We investigated how formation of urea by these two pathways is regulated in females of A. aegypti. The expression of arginase (AR) and urate oxidase (UO), either separately or simultaneously (ARUO) was silenced by RNAi. The amounts of several nitrogen compounds were quantified in excreta using mass spectrometry. Injection of mosquitoes with either dsRNA-AR or dsRNA-UO significantly decreased the expressions of AR or UO in the fat body (FB) and Malpighian tubules (MT). Surprisingly, the expression level of AR was increased when UO was silenced and vice versa, suggesting a cross-talk regulation between pathways. In agreement with these data, the amount of urea measured 48 h after blood feeding remained unchanged in those mosquitoes injected with dsRNA-AR or dsRNA-UO. However, allantoin significantly increased in the excreta of dsRNA-AR-injected females. The knockdown of ARUO mainly led to a decrease in urea and allantoin excretion, and an increase in arginine excretion. In addition, dsRNA-AR-injected mosquitoes treated with a specific nitric oxide synthase inhibitor showed an increase of UO expression in FB and MT and a significant increase in the excretion of nitrogen compounds. Interestingly, both a temporary delay in the digestion of a blood meal and a significant reduction in the expression of several genes involved in ammonia metabolism were observed in dsRNA-AR, UO or ARUO-injected females. These results reveal that urea synthesis and excretion in A. aegypti are tightly regulated by a unique cross-talk signaling mechanism. This process allows blood-fed mosquitoes to regulate the synthesis and/or excretion of nitrogen waste products, and avoid toxic effects that could result from a lethal concentration of ammonia in their tissues.
登录
查看更多内容
影响因子：
2.2
作者：
Brackney, Doug E.;Isoe, Jun;Black, W. C., IV;Zamora, Jorge;Foy, Brian D.;Miesfeld, Roger L.;Olson, Ken E.
通讯作者：
Olson, Ken E.
影响因子：
--
作者：
Rogers, D. J.;Wilson, A. J.;Hay, S. I.;Graham, A. J.
通讯作者：
Graham, A. J.
影响因子：
7.6
作者：
Weaver, Scott C.;Reisen, William K.
通讯作者：
Reisen, William K.
影响因子：
2.2
作者：
Scaraffia, Patricia Y.;Zhang, Qingfen;Thorson, Kelsey;Wysocki, Vicki H.;Miesfeld, Roger L.
通讯作者：
Miesfeld, Roger L.
影响因子：
2.2
作者：
Zhou, GL;Flowers, M;Wells, MA
通讯作者：
Wells, MA