ALBERT

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 93〈/p〉 〈p〉Author(s): Luqing Pan, Xin Zhang, Liubing Yang, Shanshan Pan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hemocyanin, a multifunctional oxygen-carrying protein, has critical effects on immune defense in crustaceans. To explore the role of hemocyanin in anti-pathogen mechanism, effects of 〈em〉Vibrio harveyi〈/em〉 (〈em〉V. harvey〈/em〉) and 〈em〉Staphyloccocus aureus〈/em〉 (〈em〉S. aureus〈/em〉) on hemocyanin synthesis and innate immune responses were investigated in 〈em〉Litopenaeus vannamei〈/em〉 (〈em〉L. vannamei〈/em〉) during infection 〈em〉in vivo〈/em〉. Results showed that 10〈sup〉5〈/sup〉 and 10〈sup〉6〈/sup〉 cells mL〈sup〉−1〈/sup〉 〈em〉V. harveyi〈/em〉 and 10〈sup〉6〈/sup〉 cells mL〈sup〉−1〈/sup〉 〈em〉S. aureus〈/em〉 significantly affected plasma hemocyanin concentration, hepatopancreas hemocyanin mRNA and subunits expressions, plasma phenol oxidase (PO), hemocyanin-derived PO (Hd-PO), antibacterial, and bacteriolytic activities during the experiment under bacterial stress, while these parameters did not change remarkably in control group. The concentration of hemocyanin in plasma fluctuated, with a minimum at 12 h and a maximum at 24 h. Moreover, the expression of hemocyanin mRNA peaked at 12 h, while the level of hemocyanin p75 and p77 subunits reached maximum at 24 h. Besides, plasma PO and Hd-PO activities peaked at 24 h, and antimicrobial and bacteriolytic activities peaked at 12 h and 24 h, respectively. In addition, 10〈sup〉5〈/sup〉 cells mL〈sup〉−1〈/sup〉 〈em〉S. aureus〈/em〉 had no significant effect on the synthesis of hemocyanin and prophenoloxidase activating (pro-PO) system, but significantly increased antimicrobial activity at 12 h and bacteriolytic activity at 24 h. Therefore, these results suggest that the hemocyanin synthesis was initiated after invasion of pathogen, and the newly synthesized hemocyanin, acted as an immune molecule, can exerts PO activity to regulate the immune defense in 〈em〉L. vannamei in vivo〈/em〉.〈/p〉〈/div〉 〈/div〉