Co-cultivation and transcriptome sequencing of two co-existing fish pathogens Moritella viscosa and Aliivibrio wodanis.

BACKGROUND: Aliivibrio wodanis and Moritella viscosa have often been isolated concurrently from fish with winter-ulcer disease. Little is known about the interaction between the two bacterial species and how the presence of one bacterial species affects the behaviour of the other. RESULTS: The impact on bacterial growth in co-culture was investigated in vitro, and the presence of A. wodanis has an inhibitorial effect on M. viscosa. Further, we have sequenced the complete genomes of these two marine Gram-negative species, and have performed transcriptome analysis of the bacterial gene expression levels from in vivo samples. Using bacterial implants in the fish abdomen, we demonstrate that the presence of A. wodanis is altering the gene expression levels of M. viscosa compared to when the bacteria are implanted separately. CONCLUSIONS: From expression profiling of the transcriptomes, it is evident that the presence of A. wodanis is altering the global gene expression of M. viscosa. Co-cultivation studies showed that A. wodanis is impeding the growth of M. viscosa, and that the inhibitorial effect is not contact-dependent.

The strains of bioluminescent bacteria isolated from the White Sea finfishes: genera Photobacterium, Aliivibrio, Vibrio, Shewanella, and first luminous Kosakonia.

Bioluminescence is a spectacular feature of some prokaryotes. In the present work, we address the distribution of bioluminescence among bacteria isolated from the White Sea finfishes. Luminous bacteria are widely distributed throughout the World Ocean. Many strains have been isolated and described for tropical latitudes, while Nordic seas still remain quite a white spot in studying bioluminescence of bacteria. We describe the strains related to the two main genera of luminous bacteria, Photobacterium and Aliivibrio, as well as Shewanella and Vibrio. They are related to families Vibrionaceae and Shewanellaceae of the Gammaproteobacteria class. Here, we at the first time, report the bioluminescence of the Enterobacteriaceae Kosakonia cowanii. Moreover, we applied the polyphasic approach to identify and describe the isolated microorganisms. The data on sequencing, diversity of cell fine structure, and light emission spectra at room temperature on the solid medium are discussed. The bacteria are characterized by features in their light emission spectra. It may reflect possible molecular mechanisms of bioluminescence as well as features of bacterial composition. The obtained data expands the existing body of knowledge about the bioluminescence spread among the bacteria of Nordic latitudes and provides complex information that is crucial for their precise identification.