Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China.
Molecules. 2012 Apr 16;17(4):4522-32. doi: 10.3390/molecules17044522.
Manganese superoxide dismutase (Mn-SOD) plays a crucial role in antioxidant responses to environmental stress. To determine whether Mn-SOD affects heat resistance of Gracilaria lemaneiformis, we cloned Mn-SOD cDNA sequences of two strains of this red alga, wild type and cultivar 981. Both cDNA sequences contained an ORF of 675 bp encoding 224 amino acid residues. The cDNA sequences and the deduced amino acid sequences of the two strains shared relatively high identity (more than 99%). No intron existed in genomic DNA of Mn-SOD in G. lemaneiformis. Southern blotting indicated that there were multiple copies, possibly four, of Mn-SOD in both strains. Both in the wild type and cultivar 981, SOD mRNA transcription and SOD activity increased under high temperature stress, while cultivar 981 was more heat resistant based on its SOD activity. This research suggests that there may be a direct relationship between SOD activity and the heat resistance of G. lemaneiformis.
锰超氧化物歧化酶（Mn-SOD）在应对环境胁迫的抗氧化反应中起着至关重要的作用。为了确定 Mn-SOD 是否影响龙须菜的耐热性，我们克隆了这种红藻的两个品系（野生型和 981 品系）的 Mn-SOD cDNA 序列。这两个 cDNA 序列都包含一个编码 224 个氨基酸残基的 675bp 的 ORF。这两个品系的 cDNA 序列和推导的氨基酸序列具有相对较高的同一性（超过 99%）。在龙须菜的基因组 DNA 中，Mn-SOD 没有内含子。Southern 印迹分析表明，两个品系中可能存在多个（可能是四个）Mn-SOD 拷贝。无论是在野生型还是 981 品系中，SOD mRNA 转录和 SOD 活性在高温胁迫下都增加，而 981 品系的 SOD 活性更高，耐热性更强。这项研究表明，SOD 活性与龙须菜的耐热性之间可能存在直接关系。
