The study of physiological adaptations to extreme environment in hydrothermal crab, Xenograpsustestudinatus: the expression patterns of sulfide:quinoneoxidoreductase and sulfide metabolism-related genes in ahigh sulfide environment

• Main Authors: Chung, Yao-Tse, 鍾曜澤
• Other Authors: Chang, Ching-Fong
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/jvbt6u

碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 106 === Xenograpsus testudinatus lived in shallow-water hydrothermal vents of Kueishan Island, northeastern Taiwan. The habitat of this vent crab contained a lethal sulfide concentration and low pH value. Thus, vent crab need to decrease this lethal sulfide level through the sulfide oxidation (sulfide-sulfite-thiosulfate pathway). In vertebrate studies, several genes was contained in sulfide oxidation pathway, including the sulfide:quinone oxidoreductase (SQR), thiosulfate sulfurtransferase rhodanase-like domain (TSTD), Sulfur dioxygenase (ETHE1), Sulfite oxidase (SO). Moreover, SQR was the key enzyme of sulfide metabolism. Thus, we would like to understand the expression profile of sulfide oxidation-related genes in different conditions in vent crab. According to our transcriptomic data, two SQR (SQR1 and SQR2), a TSTD, an ETHE1, and a SO were found in X. testudinatus. Based on the phylogenetic analysis, gene duplication of SQR was found in brachyura but not in Caridea. qPCR data showed different expression patterns of these sulfide oxidation-related genes in various tissues. Moreover, compared to the habitat crab, the sulfide oxidation-related genes had a low expression level in outward organ (gill, hepatopancreas, stomach and intestine) in the breeding crab (moved from habitat after 1 mo). No difference was found in inward organ (muscle and heart) between the habitat and breeding condition. However, the expression levels of these sulfide oxidation-related genes were not decreased in breeding crab (moved from habitat after 9 days). Furthermore, breeding vent crab (moved from habitat after 1 mo) survived in a high sulfide environment (habitat) after 2 hrs while all Thalamita danae died in this condition. The expression levels of these sulfide oxidation-related genes were not changed while the breeding crab (moved from habitat after 1 mo) removed to natural habitat after 2 hrs compared to breeding crab removed to natural sea water condition. Taken together, our result showed RNA levels of sulfide oxidation-related genes and protein levels of SQRs had no change while it faced a various sulfide levels. Thus, our data suggested that the speed of sulfide oxidation maybe regulated by the enzyme activity through the amount of cofactor.