Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway.
Sea Lice Research Centre, Institute of Marine Research, Bergen, Norway.
PLoS One. 2018 Apr 12;13(4):e0195783. doi: 10.1371/journal.pone.0195783. eCollection 2018.
The Salmon louse (Lepeophtheirus salmonis) is a marine ectoparasite of salmonid fish in the Northern Hemisphere and considered as a major challenge in aquaculture and a threat to wild populations of salmonids. Adult female lice produce a large number of lipid-rich eggs, however, the mechanism of maternal lipid transport into developing eggs during salmon louse reproduction has not been described. In the present study, a full-length L. salmonis lipophorin receptor (LsLpR) consisting of 16 exons was obtained by RACE and RT-PCR. The predicted ORF was 952 amino acids and structural analysis showed five functional domains that are similar to LpR of insects and decapods. Phylogenetic analysis placed the LsLpR together with LpRs from decapods and insects. Expression analysis revealed that the relative abundance of LsLpR transcripts was highest in the larvae and adult female lice. In adult females, the LsLpR transcripts and protein were found in the ovary and vitellogenic oocytes whereas, in larvae, the LsLpR transcripts were found in the neuronal somata of the brain and the intestine. Oil Red O stain results revealed that storage of neutral lipids was found in vitellogenic oocytes and ovaries of adult females, and in the yolk of larvae. Moreover, RNA interference (RNAi) was conducted to demonstrate the function of LsLpR in reproduction and lipid metabolism in L. salmonis. In larvae, the transcription of LsLpR was decreased by 44-54% while in an experiment LsLpR knockdown female lice produced 72% less offspring than control lice.
鲑鱼虱（Lepeophtheirus salmonis）是北半球鲑鱼科鱼类的一种海洋外寄生虫，被认为是水产养殖的主要挑战，也是鲑鱼科野生种群的威胁。成年雌性虱子会产生大量富含脂质的卵，然而，鲑鱼虱繁殖过程中母体脂质向发育中的卵的运输机制尚未描述。在本研究中，通过 RACE 和 RT-PCR 获得了全长的 L. salmonis 脂联蛋白受体（LsLpR），由 16 个外显子组成。预测的 ORF 为 952 个氨基酸，结构分析显示有 5 个功能域与昆虫和十足目动物的 LpR 相似。系统发育分析将 LsLpR 与十足目动物和昆虫的 LpRs 放在一起。表达分析显示，LsLpR 转录本在幼虫和成年雌性虱子中的丰度最高。在成年雌性虱子中，LsLpR 转录本和蛋白存在于卵巢和卵黄发生卵母细胞中，而在幼虫中，LsLpR 转录本存在于大脑和肠道的神经元体中。油红 O 染色结果显示，中性脂质的储存存在于成年雌性虱子的卵黄发生卵母细胞和卵巢中，以及幼虫的卵黄中。此外，进行了 RNA 干扰（RNAi）实验以证明 LsLpR 在鲑鱼虱生殖和脂质代谢中的功能。在幼虫中，LsLpR 的转录水平降低了 44-54%，而在实验中，LsLpR 敲低的雌性虱子比对照虱子产生的后代少 72%。
