Gene encoding prolactin in cinnamon clownfish Amphiprion melanopus and its expression upon acclimation to low salinities

Aquatic Biosystems

Jong-Myoung Kim¹  Byung Hwa Min³  Yong Jin Chang¹  Sum Rho²  Gyeong Eon Noh¹ 

[1]Department of Fishery Biology, Pukyong National University, Busan 608-737, South Korea

[2]COREA, Center of Ornamental Reefs and Aquariums, Jeju 690-974, South Korea

[3]Aquaculture Industry Division, East Sea Fisheries Research Institute, Gangneung 210-861, South Korea

关键词: Amphiprion melanopus;    Clownfish;    Osmoregulation;    Prolactin;    Osmoregulation;   

Others  :  794292
DOI  :  10.1186/2046-9063-9-1

 received in 2012-07-10, accepted in 2012-10-26,  发布年份 2013

【 摘 要 】

Background

Prolactin (PRL) is a key hormone for osmoregulation in fish. Levels of PRL in the pituitary gland and plasma ion composition of clownfish seem to change to regulate their hydromineral balance during adaptation to waters of different salinities. In order to understand osmoregulatory mechanism and its association with growth performance and PRL in fish, the gene encoding PRL and its expression level in cinnamon clownfish Amphiprion melanopus upon acclimation to low salinity was analyzed.

Results

The PRL gene of A. melanopus encoded a protein of 212 amino acid residues comprised of a putative signal peptide of 24 amino acids and a mature protein of 188 amino acids. Analysis of growth performance under different salinities of 34, 25, 15, and 10 ppt indicated that cinnamon clownfish could survive under salinities as low as 10 ppt. A higher rate of growth was observed at the lower salinities as compared to that of 34 ppt. Upon shifting the salinity of the surrounding water from 34 ppt to 15 ppt, the level of the PRL transcripts gradually increased to reach the peak level until 24 h of acclimation at 15 ppt, but decreased back as adaptation continued to 144 h. In contrast, levels of plasma Na⁺, Cl^-, and osmolality decreased at the initial stage (4–8 h) of acclimation at 15 pt but increased back as adaptation continued till 144 h.

Conclusion

Cinnamon clownfish could survive under salinities as low as 10 ppt. Upon shifting the salinity of the surrounding water from 34 ppt to 15 ppt, the level of the PRL transcripts gradually increased during the initial stage of acclimation but decreased back to the normal level as adaptation continued. An opposite pattern of changes - decrease at the beginning followed by an increase - in the levels of plasma Na⁺, Cl^-, and osmolality was found upon acclimation to low salinity. The results suggest an involvement of PRL in the processes of osmoregulation and homeostasis in A. melanopus.

【 授权许可】

   
2013 Noh et al.; licensee BioMed Central Ltd.

【 图 表 】

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