Parida Lopamudra, Paul Anirban, Mohanty Jyotirmaya, Sahoo Pramoda Kumar
National Referral Laboratory for Freshwater Fish Diseases, Fish Health Management Division, ICAR-Central Institute of Freshwater Aquaculture (CIFA), Kausalyaganga, Bhubaneswar 751002, India.
Fish Genetics and Biotechnology Division, ICAR-Central Institute of Freshwater Aquaculture (CIFA), Kausalyaganga, Bhubaneswar 751002, India.
Int J Biol Macromol. 2025 Mar;293:139353. doi: 10.1016/j.ijbiomac.2024.139353. Epub 2024 Dec 30.
Septins are evolutionarily conserved GTP-binding proteins mediating innate immunity, autophagy and inflammation in higher animals; however, they are yet to be fully characterized in fish. The study encompasses cloning of complete septin 2 cDNA from the rohu carp (Labeo rohita) that consisted of an open reading frame of 1050 bp and phylogenetic amino acid similarity of 99.43 % to cyprinid Onychostoma macrolepis. Septin 2 was ubiquitously expressed in different tissues of healthy rohu, and during early developmental stages. Septin 2 transcript levels were increased in response to three infection models i.e. Aeromonas hydrophila, poly I:C, and Argulus siamensis, indicating its role in immunity. A synthetic antimicrobial peptide derived from the septin 2 gene revealed in vitro bactericidal activity. A produced recombinant protein of septin 2 (~40 kDa) when injected into rohu modulated the expression of various immune-related genes. Further, in vivo studies of this protein demonstrated protection against A. hydrophila (71 % relative percent survival) and delayed mortality against ectoparasite A. siamensis. A developed sandwich ELISA revealed enhanced septin 2 level post A. hydrophila infection. The present study provides a new understanding of the septin 2 gene's multifunctional role in rohu and its importance in fish antimicrobial defence.
Septins是进化上保守的GTP结合蛋白，在高等动物中介导先天免疫、自噬和炎症；然而，它们在鱼类中尚未得到充分表征。该研究包括从印度鲤（Labeo rohita）中克隆完整的septin 2 cDNA，其开放阅读框为1050 bp，与鲤科的大鳞白甲鱼的系统发育氨基酸相似性为99.43%。Septin 2在健康印度鲤的不同组织以及早期发育阶段普遍表达。Septin 2转录水平在三种感染模型（即嗜水气单胞菌、聚肌胞苷酸和暹罗鲺）刺激下升高，表明其在免疫中的作用。一种源自septin 2基因的合成抗菌肽显示出体外杀菌活性。将产生的重组septin 2蛋白（约40 kDa）注射到印度鲤中可调节各种免疫相关基因的表达。此外，对该蛋白的体内研究表明其对嗜水气单胞菌具有保护作用（相对存活率71%），并能延缓体外寄生虫暹罗鲺导致的死亡。一种开发的夹心ELISA显示嗜水气单胞菌感染后septin 2水平升高。本研究为septin 2基因在印度鲤中的多功能作用及其在鱼类抗菌防御中的重要性提供了新的认识。
