title: Effect of ammonia-N and pathogen challenge on complement component 8α and 8β expression in the darkbarbel catfish Pelteobagrus vachellii.
abstract: The complement components C8α and C8β mediate the formation of the membrane attack complex (MAC) to resist pathogenic bacteria and play important roles in innate immunity. Full-length complement C8α (Pv-C8α) and C8β (Pv-C8β) cDNA were identified in the darkbarbel catfish Pelteobagrus vachellii, and their mRNA expression levels were analyzed after ammonia-N and pathogen treatment. The Pv-C8α gene contained 1983 bp, including a 1794-bp open reading frame (ORF) encoding 598 amino acids. The Pv-C8β gene contained 1952 bp, including a 1761-bp ORF encoding 587 amino acids. Pv-C8α and Pv-C8β had the highest amino acid identity with rainbow trout Oncorhynchus mykiss C8α (62%) and Japanese flounder Paralichthys olivaceus C8β (83%), respectively. Sequence analysis indicated that both Pv-C8α and Pv-C8β contained a thrombospondin type-1 (TSP1) domain, a low-density lipoprotein receptor class A (LDLR-A) domain, a membrane attack complex/perforin (MACPF) domain and an epidermal growth factor-like (EGF-like) domain. In addition, Pv-C8α and Pv-C8β were mainly distributed in the liver, head kidney, spleen, and eggs. Under ammonia-N stress, the Pv-C8α and Pv-C8β mRNA levels significantly decreased (P < 0.05), with minimum levels, respectively, attained at 24 and 48 h in the liver, 48 and 24 h in the head kidney, and 24 and 24 h in the spleen. After Aeromonas hydrophila challenge, the Pv-C8α and Pv-C8β mRNA levels significantly increased (P < 0.05), with maximum levels, respectively, attained at 48 and 24 h in the liver, 24 and 48 h in the head kidney, and 48 and 48 h in the spleen. The present study indicated that Pv-C8α and Pv-C8β exhibited important immune responses to infection and that ammonia-N in water decreased the immune responses of Pv-C8α and Pv-C8β.
authors.affiliation: College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China. Electronic address: qinchuanjie@126.com.
authors.forename: Chuanjie
authors.initials: C
authors.lastname: Qin
authors.affiliation: College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China; College of Life Science, Sichuan Normal University, Chengdu 610101, PR China.
authors.forename: Ting
authors.initials: T
authors.lastname: Shao
authors.affiliation: School of Life Sciences, Nanchang University, Jiangxi 330031, PR China.
authors.forename: Daxian
authors.initials: D
authors.lastname: Zhao
authors.affiliation: College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China.
authors.forename: Huiguo
authors.initials: H
authors.lastname: Duan
authors.affiliation: College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China.
authors.forename: Zhengyong
authors.initials: Z
authors.lastname: Wen
authors.affiliation: College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China.
authors.forename: Dengyue
authors.initials: D
authors.lastname: Yuan
authors.affiliation: College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China.
authors.forename: Huatao
authors.initials: H
authors.lastname: Li
authors.affiliation: College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China.
authors.forename: Zemin
authors.initials: Z
authors.lastname: Qi
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology; D000595:Amino Acid Sequence; D000641:Ammonia / Q000633:toxicity*; D000818:Animals; D002397:Catfishes; D003001:Cloning, Molecular; D003185:Complement C8 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016905:Gram-Negative Bacterial Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011897:Random Allocation; D016415:Sequence Alignment / Q000662:veterinary
chemical_list: D003185:Complement C8; D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D000641:Ammonia
keywords: Ammonia-N; Complement component 8α; Complement component 8β; Immune stimulation; Pelteobagrus vachellii