Neuroendocrine Control of Salinity-Mediated Carbonic Anhydrase Expression in the Gills of Euryhaline Crustaceans

这项研究将研究生物体如何感知环境变化的机制，以及它们如何通过打开赋予它们新的生理能力的特定基因来适应这些变化。重点放在甲壳类动物上。泛盐甲壳类动物是指那些能耐受水中各种盐分浓度的甲壳类动物，从开阔的海洋到淡水河流。一般来说，他们通过摄取盐(钠和氯化物)来达到这一目的，从而保持重要血盐的恒定浓度。这种能力的分子基础是在鳃中表达的一套运输蛋白。已经确定了一些蛋白质，它们负责单个离子的运输。转运机制通常涉及吸收重要离子以换取废物的离子形式(例如，Na+/H+和Cl-/HCO3-交换)。废水是二氧化碳和水反应产生的，该反应是由碳酸酐酶(CA)催化的。由于H+和HCO3-一般用来交换阳离子和阴离子，CA被认为是整个离子吸收机制中的一个中心支撑酶。此外，当这些生物暴露在低盐度下时，CA的表达上调。初步证据表明，这种调节机制只存在于真盐物种中，并且受到甲壳类主要内分泌系统--X器官/鼻窦腺复合体中发现的CA抑制物(据信是一种神经肽)的抑制控制。该多肽将通过高效液相色谱进行鉴定，并通过定量聚合酶链式反应和报告酶分析来研究其对CA表达的影响。这项研究也有更广泛的影响，因为河口是高生产力的环境，正在研究的一个物种具有重要的经济意义(例如，Callinectes senidus)，而另一个物种(Carcinus Maenas)是一种入侵物种，在生态和经济上都造成了破坏。该项目还将包括在研究的所有阶段对本科生、研究生和博士后助理进行培训。

This study will examine mechanisms of how organisms sense environmental changes, and how they adapt to cope with these changes by turning on specific genes that give them new physiological abilities. The focus is on crustaceans. Euryhaline crustaceans are those that tolerate a wide range of salt concentrations in water, from the open ocean to freshwater rivers. In general, they do so by taking up salts (sodium and chloride), thus maintaining constant concentrations of vital blood salts. The molecular basis of this ability is a suite of transport proteins that are expressed in the gill. A number of proteins have been identified that are responsible for the transport of individual ions. The mechanism of transport usually involves the uptake of a vital ion in exchange for the ionic form of a waste product (e.g., Na+/H+ and Cl-/HCO3- exchange). The waste products are produced from the reaction of CO2 and water, which is catalyzed by the enzyme carbonic anhydrase (CA). Because H+ and HCO3- are used in exchange for cations and anions in general, CA is believed to be a central support enzyme in the overall mechanism of ion uptake. Furthermore, the expression of CA is up-regulated when these organisms are exposed to low salinity. Preliminary evidence indicates that the regulatory mechanism is present only in euryhaline species and that it is under inhibitory control by a CA repressor (believed to be a neuropeptide) found in the major endocrine system of crustaceans, the X-organ/sinus gland complex. This peptide will be identified by HPLC, and its action on CA expression investigated through the use of quantitative PCR and reporter enzyme assays. This research also has broader impacts, because estuaries are highly productive environments, and one species being studied is economically important (e.g., Callinectes sapidus) whereas the other (Carcinus maenas) is an invasive species that has been both ecologically and economically disruptive. The project will also involve the training of undergraduate students, graduate students, and postdoctoral associates in all phases of the research.