Department of Fishery Microbiology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore 575 002, India.
Res Microbiol. 2012 May;163(4):286-91. doi: 10.1016/j.resmic.2012.03.001. Epub 2012 Apr 21.
The gene coding for an outer membrane protein Omp48 of Aeromonas hydrophila isolated from an infected fish was cloned and sequenced. Analysis of nucleotide sequence showed the omp48 gene to be an adhesin encoding a protein of 426 amino acids with high identity to the omp48 gene of Aeromonas veronii, another fish pathogen. The gene belonged to the maltoporin group of porins and had high similarity to LamB porins of A. hydrophila, Aeromonas salmonicida and Vibrio parahaemolyticus. The expressed purified recombinant protein had an estimated molecular weight of 48 kDa. Further, rabbit hyperimmune sera against the recombinant protein reacted with A. hydrophila, Aeromonas sobria and A. veronii whole cell proteins at the region of 48 kDa, in western blotting. The recombinant protein was immunogenic in the fish Labeo rohita Hamilton. Fish immunized with recombinant protein, when challenged with virulent A. hydrophila and another bacterial fish pathogen, Edwardsiella tarda, showed relative percent survivals of 69 and 60, respectively. Our results suggest that Omp48 of A. hydrophila could be used as a potential vaccine candidate for protection not only against A. hydrophila infection, but also against the fish pathogen E. tarda.
从感染鱼类中分离出的嗜水气单胞菌外膜蛋白 Omp48 的基因被克隆和测序。核苷酸序列分析表明，omp48 基因是一种黏附素编码蛋白，由 426 个氨基酸组成，与另一种鱼类病原体维氏气单胞菌的 omp48 基因高度同源。该基因属于麦芽糖透酶组孔蛋白，与嗜水气单胞菌、鲑鱼气单胞菌和副溶血弧菌的 LamB 孔蛋白具有高度相似性。表达的纯化重组蛋白估计分子量为 48 kDa。此外，兔抗重组蛋白的多克隆血清在 Western blot 中与嗜水气单胞菌、温和气单胞菌和维氏气单胞菌的全细胞蛋白在 48 kDa 处发生反应。重组蛋白在鱼类罗非鱼中具有免疫原性。用重组蛋白免疫的鱼类在受到强毒嗜水气单胞菌和另一种鱼类病原菌爱德华氏菌的攻击时，相对存活率分别为 69%和 60%。我们的结果表明，嗜水气单胞菌的 Omp48 可以作为一种潜在的疫苗候选物，不仅可以预防嗜水气单胞菌感染，还可以预防鱼类病原菌爱德华氏菌的感染。
