Vibrio harveyi belongs to the Vibrio genus that causes vibriosis in marine and aquatic fish species through double-stranded DNA virus replication. In humans, around 12 Vibrio species can cause gastroenteritis (gastrointestinal illness). A large amount of virus particles can be found in the cytoplasm of infected cells, which may cause death. Despite these devastating complications, there is still no cure or vaccine for the virus. As a result, we used an immunoinformatics approach to develop a multi-epitope vaccine against most pathogenic hemolysin gene of V. harveyi. The immunodominant T- and B-cell epitopes were identified using the hemolysin protein. We developed a vaccine employing three possible epitopes: cytotoxic T-lymphocytes, helper T-lymphocytes, and linear B-lymphocyte epitopes, after thorough testing. The vaccine was developed to be antigenic, immunogenic, and non-allergenic, as well as having a better solubility. Molecular dynamics simulation revealed significant structural stiffness and binding stability. In addition, the immunological simulation generated by computer revealed that the vaccination might elicit immune reactions in the actual life after injection. Finally, using Escherichia coli K12 as a model, codon optimization yielded ideal GC content and a higher codon adaptation index value, which was then included in the cloning vector pET2+ (a). Altogether, our experiment implies that the proposed peptide vaccine might be a good option for vibriosis prophylaxis.

Aims: Coral diseases have emerged over the last several decades, causing a loss of live coral cover in the Caribbean and Indo-Pacific reefs. Hence, microbiological and disease cultural techniques are commonly used to investigate their causative microbial agents. This is the first study to identify the potential of pathogenic Vibrio spp. isolated from apparently white syndrome (WS) coral disease in Tioman Island Marine Park using biochemical and molecular techniques. Methodology and results: The Vibrio colonies were isolated from 108 samples of WS infected corals (Acropora cytherea and Montipora aequituberculata) including seawater, sediment and algae found adjacent to infected coral colonies. A total of one hundred representative Vibrio isolates were characterized and most of them (n=50) were identified as V. vulnificus, V. alginolyticus and Photobacterium damselae following biochemical analysis. The molecular analysis revealed six Vibrio spp. (V. coralliilyticus, V. hepatarius, V. brasiliensis, V. tubiashi, V. campbellii, V. ishigakensis) and one Photobacterium rosenbergii. Vibrio coralliilyticus isolated from all infected coral samples may be highly responsible for the sign of WS disease. Conclusion, significance and impact of study The findings of this study provide baseline data and information on potential coral pathogens identified in the coastal waters of Tioman Island. Etiological disease study is suggested to validate their severity and virulence factors in the future.
Vibrio--pathogenicity ; Anthozoa