Superoxide dismutase （SOD） is one of the most important antioxidant defense enzymes, and is considered as the first line against oxidative stress. In this study, we cloned a mitochondrial manganese （Mn） SOD （mMn...Superoxide dismutase （SOD） is one of the most important antioxidant defense enzymes, and is considered as the first line against oxidative stress. In this study, we cloned a mitochondrial manganese （Mn） SOD （mMnSOD） cDNA from the ridgetail white prawn Exopalaemon carinicauda by using rapid amplification of cDNA ends （RACE） methods. The fulMength cDNA for mMnSOD was 1 014-bp long, containing a 5＇-untranslated region （UTR） of 37-bp, a 3＇-UTR of 321-bp with a poly （A） tail, and included a 657-bp open reading frame encoding a protein of 218 amino acids with a 16-amino-acid signal peptide. The protein had a calculated molecular weight of 23.87 kDa and a theoretical isoelectric point of 6.75. The mMnSOD sequence included two putative N-glycosylation sites （NHT and NLS）, the MnSOD signature sequence 18~DVWEHAYY^87, and four putative Mn binding sites （H48, H96, D180, and H184）. Sequence comparison showed that the mMnSOD deduced amino acid sequence of E. carinicauda shared 97%, 95%, 89%, 84%, 82%, 72%, and 69% identity with that ofMacrobrachium rosenbergii, Macrobrachium nipponense, Fenneropeneaus chinensis, Callinectes sapidus, Perisesarma bidens, Danio rerio, and Homo sapiens, resectively. Quantitative real-time RT-PCR analysis showed that mMnSOD transcripts were present in all E. carinicauda tissues examined, with the highest levels in the hepatopancreas. During an ammonia stress treatment, the transcript levels of mMnSOD and cMnSOD were up-regulated at 12 h in hemocytes and at 24 h in the hepatopancreas. As the duration of the ammonia stress treatment extended to 72 h, the transcript levels of mMnSOD and cMnSOD significantly decreased both in hemocytes and hepatopancreas. These findings indicate that the SOD system is induced to respond to acute ammonia stress, and may be involved in environmental stress responses in E. carinicauda.展开更多
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A409)the Modern AgroIndustry Technology Research System(No.CARS-47)+1 种基金the Special Fund for Independent Innovation of Shandong Province(No.2013CX80202)the Special Fund for Agro-Scientific Research in the Public Interest(No.201103034)
文摘Superoxide dismutase （SOD） is one of the most important antioxidant defense enzymes, and is considered as the first line against oxidative stress. In this study, we cloned a mitochondrial manganese （Mn） SOD （mMnSOD） cDNA from the ridgetail white prawn Exopalaemon carinicauda by using rapid amplification of cDNA ends （RACE） methods. The fulMength cDNA for mMnSOD was 1 014-bp long, containing a 5＇-untranslated region （UTR） of 37-bp, a 3＇-UTR of 321-bp with a poly （A） tail, and included a 657-bp open reading frame encoding a protein of 218 amino acids with a 16-amino-acid signal peptide. The protein had a calculated molecular weight of 23.87 kDa and a theoretical isoelectric point of 6.75. The mMnSOD sequence included two putative N-glycosylation sites （NHT and NLS）, the MnSOD signature sequence 18~DVWEHAYY^87, and four putative Mn binding sites （H48, H96, D180, and H184）. Sequence comparison showed that the mMnSOD deduced amino acid sequence of E. carinicauda shared 97%, 95%, 89%, 84%, 82%, 72%, and 69% identity with that ofMacrobrachium rosenbergii, Macrobrachium nipponense, Fenneropeneaus chinensis, Callinectes sapidus, Perisesarma bidens, Danio rerio, and Homo sapiens, resectively. Quantitative real-time RT-PCR analysis showed that mMnSOD transcripts were present in all E. carinicauda tissues examined, with the highest levels in the hepatopancreas. During an ammonia stress treatment, the transcript levels of mMnSOD and cMnSOD were up-regulated at 12 h in hemocytes and at 24 h in the hepatopancreas. As the duration of the ammonia stress treatment extended to 72 h, the transcript levels of mMnSOD and cMnSOD significantly decreased both in hemocytes and hepatopancreas. These findings indicate that the SOD system is induced to respond to acute ammonia stress, and may be involved in environmental stress responses in E. carinicauda.
