黄颡鱼源铜绿假单胞菌PA-5的分离及其对寄主抗菌肽基因的影响.

[Objective] This paper aimed to isolate and identify the pathogen species of Pseudobagrus fulvidraco in Tongwang farm of Han chuan city, Hubei province, and the characteristics of its effects on the expression of antimicrobial peptide gene in host were analyzed, so as to provide a research basis for the prevention and treatment of the disease. [Method] The pathogen PA-5 from the liver of diseased Pel teobagrus fulvidraco by line culture was isolated. Gram staining and microscopic observation showed that the morphology of the pathogen was rod-shaped and gram-negative. The pathogen was sensitive to d-Gluconic acid, malonic acid and glucose, but insensitive to myxin, aescin and arabinose. The 16S rRNA and gyrB gene sequences of the strain were analyzed by multiplex PCR. [Result] It was found that the charac teristic sequence of the strain was similar to that of P. aeruginosa, the genetic relationship was close, and after synthesis, the pathogen was identified as P. aeruginosa. At the same time, the expression of antimicrobial peptide gene PCl / PC2 / PC3 in the host was analyzed after the pathogen was infected with P.fulvidraco. P. aeruginosa PA5 ( 3. 0 x 106 CFU/ mL) was injected into the abdominal cavity of P. fulvidraco, and the liver, kidney and epidermis of P. fulvidraco were dissected 0 - 96 hours after infection. Then the total RNA of P. fulvidraco was obtained by Trizol kit, the cDNA was synthesized by reverse transcription, and the expres sion characteristics of antibacterial peptide gene PCl / PC2 / PC3 gene in P. fulvidraco was analyzed by real-time fluorescent quantitative PCR. After P. aeruginosa PA-5 infected P. fulvidraco, the rela tive expression of antimicrobial peptide gene PCl / PC2 / PC3 in liver tissue was higher than that in control group at 24 and 36 hours ( P < 0. 05) ; The relative expression level of antimicrobial peptide gene PCl / PC2 / PC3 in host kidney tissue was higher than that in control group at 24 and 36 hours (P < 0.05); The relative expression of antimicrobial peptide gene PCl / PC2 / PC3 in host epidermis was 36, 48 hours was higher than that in the control group ( P < 0. 05) . The expression of antimicrobial peptide gene in liver, kidney and epidermis increased rapidly, but the reaction time of liver and kidney was earlier than that of epidermis. [Conclusion] Therefore, P. aeruginosa PA-5 was the main pathogen of P. fulvidraco in Tongwang farm of Hanchuan city, Hubei province. The host antimicrobial peptide gene PC1/PC2/ PC3 would respond positively to the infection of P. aeruginosa in Tongwang farm of Hanchuan city, Hubei province, which were conductive to antimicrobial infection. [ABSTRACT FROM AUTHOR]