Fish Nutrition and Growth Endocrinology Group, Department of Marine Species Biology, Culture and Pathology, Institute of Aquaculture Torre de la Sal, CSIC, Castellón, Spain.
Fish Shellfish Immunol. 2011 Aug;31(2):294-302. doi: 10.1016/j.fsi.2011.05.015. Epub 2011 May 27.
The aim of this work was to underline the physiological role of the antioxidant peroxiredoxin (PRDX) family in gilthead sea bream (Sparus aurata L.), a perciform fish extensively cultured in the Mediterranean area. First, extensive BLAST searches were done on the gilthead sea bream cDNA database of the AQUAMAX European Project (www.sigenae.org/iats), and six contigs were unequivocally identified as PRDX1-6 after sequence completion by RT-PCR. The phylogenetic analysis evidenced three major clades corresponding to PRDX1-4 (true 2-Cyst PRDX subclass), PRDX5 (atypical 2-Cys PRDX subclass) and PRDX6 (1-Cys PRDX subclass) that reflected the present hierarchy of vertebrates. However, the PRDX2 branch of modern fish including gilthead sea bream was related to the monophyletic PRDX1 node rather than to PRDX2 cluster of mammals and primitive fish, which probably denotes the acquisition of novel functions through vertebrate evolution. Transcriptional studies by means of quantitative real-time PCR evidenced a ubiquitous PRDX gene expression that was tissue specific for each PRDX isoform. In a second set of transcriptional studies, liver and head kidney were chosen as target tissues in fish challenged with i) the intestinal parasite Enteromyxum leei, ii) a plant oil (VO) diet with deficiencies in essential fatty acids and iii) prolonged exposure to high-rearing densities. These studies showed that PRDX genes were highly and mostly constitutively expressed in the liver and were not affected by dietary intervention or high density. In contrast, head kidney was highly sensitive to the different experimental challenges: significantly lower values were found for PRDX5 in the three trials, for PRDX6 in parasitized and high density fish and for PRDX1 in parasitized and VO fish. PRDX2, 3 and 5 were decreased only in VO, high density and parasitized animals, respectively. These findings would highlight the role of PRDXs as integrative and highly predictive biomarkers of health and welfare in fish and gilthead sea bream in particular.
本研究旨在强调抗氧化酶过氧化物酶 (PRDX) 家族在金头鲷 (Sparus aurata L.) 中的生理作用，金头鲷是一种广泛养殖于地中海地区的鲈形目鱼类。首先，我们在 AQUAMAX 欧洲项目的金头鲷 cDNA 数据库（www.sigenae.org/iats）上进行了广泛的 BLAST 搜索，并通过 RT-PCR 完成序列后，明确鉴定了 6 个连续序列为 PRDX1-6。系统发育分析表明，有三个主要分支对应于 PRDX1-4（真正的 2-Cys PRDX 亚类）、PRDX5（非典型的 2-Cys PRDX 亚类）和 PRDX6（1-Cys PRDX 亚类），反映了现生脊椎动物的分类阶元。然而，包括金头鲷在内的现代鱼类的 PRDX2 分支与单系的 PRDX1 节点相关，而不是与哺乳动物和原始鱼类的 PRDX2 聚类相关，这可能表明在脊椎动物进化过程中获得了新的功能。通过定量实时 PCR 的转录研究表明，PRDX 基因具有普遍的组织表达特异性。在第二组转录研究中，肝脏和头肾被选为金头鲷感染肠道寄生虫 Enteromyxum leei、②缺乏必需脂肪酸的植物油脂 (VO) 饮食和③长时间暴露于高密度养殖环境后的靶组织。这些研究表明，PRDX 基因在肝脏中高度且主要组成型表达，不受饮食干预或高密度的影响。相比之下，头肾对不同的实验挑战高度敏感：在这三个试验中，PRDX5 的值显著降低，PRDX6 在感染和高密度鱼类中降低，PRDX1 在感染和 VO 鱼类中降低。PRDX2、3 和 5 仅在 VO、高密度和感染动物中降低。这些发现将突出 PRDX 作为鱼类和金头鲷健康和福利的综合和高度预测生物标志物的作用。
