Search

Vibriosis caused by luminous Vibrio species is one of the biggest challenges to shrimp industry in Bangladesh. This study aimed to characterize whole microbial communities from Vibrio‐infected black tiger shrimp (Penaeus monodon) using 16S rRNA‐based amplicon sequencing. A total of 36 disease‐free and infected shrimp were collected from six different hatcheries in Bagerhat, Bangladesh. A final pool of 12 samples (n = 6) was created by homogenization of the hepatopancreas samples from three shrimps collected from each hatchery for the same group. The amplicon sequencing data revealed significant (p <.05) decrease of alpha diversity measurements and subsequent effects (p <.05) on the hepatopancreas microbiota in the infected group, compared to control shrimp. Proteobateria and Aeromonas were the most dominant bacteria at phylum and genus level in both groups and identified as core microbiota in the community. Two bacterial groups at phyla level and eight at genus level were found associated with the alteration of hepatopancreas microbial communities and associated gene functions in vibriosis‐infected shrimp, revealed by differential abundance and KEGG pathway analysis. The overwhelming abundance of Citroibacter, Shewanella and Candidatus lineages in vibriosis‐infected shrimp needs further investigations. [ABSTRACT FROM AUTHOR]

Aerolysin (aer) is one of the most important and abundant virulence factors in the infection of fish by Aeromonas veronii. A comprehensive study on the molecular characterization and pathogenicity of the aer gene from 34 A. veronii isolates from diseased carp and catfish was carried out and its interactome was analysed to observe the functional correlations between aer and other proteins within the A. veronii network. The PCR‐based amplification of aer from the 34 isolates of A. veronii showed more aer‐positive isolates from catfish with a high pathogenic potential in the in vivo challenge test than the carp fish. The analysis of aer gene sequence from challenged fish revealed significant sequence divergence according to the types and geographical distribution of the fish. The networking analysis of aer from the model A. veronii B565 revealed histidine kinase (cheA) as the most functional interacting partner. The study of the interaction between aer from the experimental A. veronii and cheA demonstrated that the A chain of cheA plays a more important role than the corresponding B chain during contact, and a linker sequence of 15 residues controlled the entire interaction process. Therefore, cheA could be an excellent drug target for controlling A. veronii infection of fish. [ABSTRACT FROM AUTHOR]