Partial Characterization of Three Bacteriophages Isolated from Aquaculture Hatchery Water and Their Potential in the Biocontrol of Vibrio spp.

Bacteriophages are currently considered one of the most promising alternatives to antibiotics under the 'One Health' approach due to their ability to effectively combat bacterial infections. This study aimed to characterize Vibrio species in hatchery water samples collected from an aquaculture farm and investigate the biocontrol potential of their bacteriophages. Vibrio spp. (n = 32) isolates confirmed by LNA probe-based qPCR were used as hosts. Three Vibrio phages were isolated. IKEM_vK exhibited a broad host range, infecting V. harveyi (n = 8), V. alginolyticus (n = 2), V. azureus (n = 1), and V. ordalii (n = 1). IKEM_v5 showed lytic activity against V. anguillarum (n = 4) and V. ordalii (n = 1), while IKEM_v14 was specific to V. scophtalmi (n = 4). The morphological appearance of phages and their lytic effects on the host were visualized using scanning electron microscopy (SEM). All three phages remained relatively stable within the pH range of 6-11 and up to 60 °C. The lytic activities and biofilm inhibition capabilities of these phages against planktonic Vibrio cells support their potential applications in controlling vibriosis in aquaculture systems.

Synthesis and immunomodulation of human lymphocyte proliferation and cytokine (interferon-γ) production of four novel leflunomide analogues.

Leflunomide is an immunomodulating drug that has been used clinically for the treatment of rheumatoid arthritis and other immune system disorders. As a continuation of our previous work, four novel analogues of leflunomide (6a, 6b, 7a and 7b) were synthesized; here, an imidazolyl group has replaced the isoxazolyl moiety, while the 4-trifluoromethylphenyl group has been retained. These analogues were synthesized and investigated in vitro for their immunomodulating activity by examining human lymphocyte proliferation and determining the cytokine interferon-γ concentrations in human lymphocyte cells. For this purpose, 5 x 10(4) human lymphocyte cells were incubated at 37°C in 5% CO(2) with phytohemagglutinin and one of the analogues (concentrations ranging from 1 to 100 mM), negative controls or cyclosporine (0.1 mM). The compounds' effects on lymphocyte proliferation and interferon-γ (IFN-γ) production were determined using an MTT assay and an ELISA, respectively. All compounds were found to have significant effects on both lymphocyte proliferation and IFN-γ production in comparison to the negative control. However, the compounds' effects were weaker than those of the positive control. Some differences among compounds 6a, 6b, 7a and 7b were seen on lymphocyte proliferation and cytokine production. Compound 6a (R=CH(3) containing a trifluoromethylaniline moiety) suppressed lymphocyte proliferation and IFN-γ production with a potency comparable to the positive control. Therefore, further studies to evaluate the compound's effects in clinical conditions are suggested.