isopropyl-thiogalactoside and Fish-Diseases

The transcription factor JunB can induce physiological or pathological responses to various stimuli, including immune stimulants and bacteria, and plays an important role in the immune response process. In this study, we identified a JunB family member in Schizothorax prenanti (S. prenanti), which was designated SpJunB. The complete coding sequence (CDS) of SpJunB was 930 bp in length, which was submitted to GenBank (ID: MN215886). SpJunB encodes a putative protein of 309 amino acids, which is highly homologous to JunB of common carp. The SpJunB protein contained a conserved JunB domain, and its 3D structure was also highly similar to (77.61%) the human SpJunB protein. SpJunB was found to be extensively expressed in various tissues, with the highest expression in the spleen. The expression of SpJunB was significantly upregulated after Aeromonas hydrophila (A. hydrophila) challenge. Prokaryotic expression indicated that a 51 kDa recombinant protein was obtained after induction with 1.5 mmol/L isopropyl-beta-D-thiogalactopyranoside (IPTG) for 6 h at 37 °C. The expression levels of IL-1β, IL-6 and IL-8 were significantly upregulated (p < 0.01) after treatment of S. prenanti with the SpJunB protein. The activities of SOD, AKP and LZM were also significantly increased (p < 0.01) after the treatment of S. prenanti with the SpJunB protein. Simultaneously, the SpJunB protein reduced the infection rate of A. hydrophila in S. prenanti. In conclusion, SpJunB may improve the immune functions of S. prenanti. It will be beneficial to further study the immune mechanism of JunB in fish.

Topics: Aeromonas hydrophila; Animals; Cloning, Molecular; Cyprinidae; Fish Diseases; Fish Proteins; Gram-Negative Bacterial Infections; Humans; Immunity, Innate; Interleukin-1beta; Interleukin-6; Interleukin-8; Isopropyl Thiogalactoside; Phylogeny; Protein Domains; Transcription Factors

This study was carried out to determine the antibody responses and protective capacity of an inactivated recombinant vaccine expressing the cell wall surface anchor family protein of Streptococcus agalactiae following oral vaccination against streptococcosis in tilapia. Tilapia were vaccinated orally with 10(6) CFU/mL of the recombinant vaccine incorporated in feed (feed-based recombinant vaccine) (vaccinated group or Group 1), 10(6) CFU/mL of pET-32 Ek/LIC vector without cell wall surface anchor family protein (control group or Group 2), 10(6) CFU/mL of formalin-killed cells of S. agalactiae vaccine incorporated in feed was also prepared (feed-based vaccine) (vaccinated group or Group 3), and unvaccinated control group or Group 4 (fed with commercial pellets). During the course of study, serum, mucus and gut lavage fluid were collected to evaluate the antibody levels via enzyme-linked immunosorbent assay (ELISA). The results showed that tilapia immunized with the feed-based recombinant vaccine developed a strong and significantly (P < 0.05) higher IgM antibody response in serum, mucus and gut lavage fluid samples compared to groups 2, 3 and 4. Following heat intervenes and intraperitoneal challenge, the rate of survivors (RPS) was 70% for the vaccinated group, and 0% for the rest of the groups. Therefore, the study revealed that the feed-based recombinant vaccine significantly provides high protection against high dose challenge in heat stress environment and enhances the production of the mucosal and humoral immunity.

Topics: Analysis of Variance; Animal Feed; Animals; Bacterial Vaccines; Base Sequence; DNA Primers; Enzyme-Linked Immunosorbent Assay; Fish Diseases; Isopropyl Thiogalactoside; Malaysia; Molecular Sequence Data; Polymerase Chain Reaction; Streptococcal Infections; Streptococcus agalactiae; Tilapia; Vaccines, Synthetic