Center for Marine Functional Genomics, Mount Desert Island Biological Laboratory, Salisbury Cove, ME 04672 USA.
Comp Biochem Physiol Part D Genomics Proteomics. 2008 Dec;3(4):263-9. doi: 10.1016/j.cbd.2008.07.001.
Two partial mRNA sequences predicted to encode anti-lipopolysaccharide factors (ALFs) were identified among expressed sequence tags generated from the American lobster Homarus americanus and complete cDNA sequences were obtained from library clones. Comparison of the translated amino acid sequences to those publicly available confirmed similarity to arthropod anti-lipopolysaccharide factors. Both protein sequences, designated ALFHa-1 and ALFHa-2, contained an N-terminal signal peptide and two half-cysteines participating in a disulfide bridge, features conserved in other ALFs. Predicted secondary structures were similar to that described for the ALF from the horseshoe crab Limulus polyphemus. As part of an exploratory study of immunity in H. americanus, lobsters were injected with the bacterium Vibrio fluvialis and gill, hematopoietic, and hepatopancreas tissues were sampled for analysis of gene expression of ALFHa-1 and ALFHa-2 by quantitative PCR. The relative abundance of ALFHa-2 mRNA was not significantly affected by Vibrio injection in any of the three tissues tested. In contrast, ALFHa-1 mRNA levels in gills were increased by the treatment some 17-fold. Our results support a molecularly specific regulation of antimicrobial proteins in response to bacterial infection in H. americanus.
从美洲螯龙虾 Homarus americanus 的表达序列标签中鉴定出两个预测编码抗脂多糖因子 (ALF) 的部分 mRNA 序列，并从文库克隆中获得了完整的 cDNA 序列。将翻译的氨基酸序列与公开提供的序列进行比较，证实与节肢动物抗脂多糖因子具有相似性。这两种蛋白质序列，分别命名为 ALFHa-1 和 ALFHa-2，均含有一个 N 端信号肽和两个参与二硫键形成的半胱氨酸，这是其他 ALF 所共有的特征。预测的二级结构与马蹄蟹 Limulus polyphemus 的 ALF 描述相似。作为对美洲螯龙虾免疫的探索性研究的一部分，用细菌 Vibrio fluvialis 注射螯龙虾，并取样鳃、造血和肝胰腺组织，通过定量 PCR 分析 ALFHa-1 和 ALFHa-2 的基因表达。在三种测试的组织中，Vibrio 注射均未显著影响 ALFHa-2 mRNA 的相对丰度。相比之下，处理后虾鳃中的 ALFHa-1 mRNA 水平增加了约 17 倍。我们的结果支持在美洲螯龙虾中针对细菌感染进行抗菌蛋白的分子特异性调控。
