Significance of Na+ in the fish pathogen, Vibrio anguillarum, under energy depleted condition

Abstract

Vibrio anguillarum kills various kinds of fish over salinities ranging from seawater to freshwater. In this study, we investigated the role of Na(+) in V. anguillarum, especially under energy-depleted conditions such as in natural seawater. V. angustum S14, which is a typical marine vibrio, was used for comparison. V. anguillarum only required Na(+) for starvation-survival, but in contrast, V. angustum S14 always required Na(+) for both growth and starvation-survival. In marine vibrios, Na(+) is used in the Na(+)-dependent respiratory chain that produces the sodium motive force (SMF) across the cell membrane. It has been considered that marine vibrios always need a SMF produced by Na(+), however in the case of V. anguillarum, the SMF is not required for growth, but becomes more important for starvation-survival.

A comprehensive review of Vibrio (Listonella) anguillarum: ecology, pathology and prevention

“…Na + and K + enhance nicotinamide adenine dinucleotide hydride (NADH) oxidase activity in V. anguillarum , but the pathogen is not dependent upon these ions for NADH oxidase functionality due to adaptations made in the marine environment which explain why the cell can remain virulent in freshwater settings (Fujiwara‐Nagata et al . , ). The gene nqr A is involved in respiratory chain functions specific to NADH quinone oxidoreductase which functions as a result of the promoters nqr P1 and nqr P2.…”

“…). Vibrio anguillarum utilizes a proton motive force to inwardly direct nutrients during the infection of a host but when viable in seawater the cell must utilize a sodium motive force to survive under conditions of stressed starvation which is why the pathogen requires Na + from salt for long‐term survival (Fujiwara‐Nagata & Eguchi ). Na + and K + enhance nicotinamide adenine dinucleotide hydride (NADH) oxidase activity in V. anguillarum , but the pathogen is not dependent upon these ions for NADH oxidase functionality due to adaptations made in the marine environment which explain why the cell can remain virulent in freshwater settings (Fujiwara‐Nagata et al .…”

The effect of oral immuno-stimulation in juvenile carp (Cyprinus carpio L.)

“…This bacterial species is commonly considered halophilic and thus a particularly marine pathogen [44]. However, previous work has investigated the effects of low salinity on bacterial survival and shown that this pathogen can survive in freshwater conditions [45,46]. Other work has reported isolation of V. anguillarum from freshwater [47,48] and there are reports of isolation of this pathogen from freshwater fish [49e51].…”

Transcriptional regulation of the Na+-NADH:quinone oxidoreductase gene, nqr, in Vibrio�anguillarum, a fish pathogen, in the stationary phase

“…Bacteria require energy for these physiological events. Thus, it is reasonable for starved bacteria to adopt a more energy‐saving way of maintaining membrane potential, such as an Na + gradient across the cell membrane 2 . In order to test this hypothesis, we investigated the transcriptional regulation of the Na + ‐NQR gene during the logarithmic growth and stationary phase in V. anguillarum .…”

“…1 However, in our previous study, we found that V. anguillarum does not necessarily require NaCl for its growth, but in fact requires NaCl for its starvation-survival. 2 Physiological cellular functions, such as substrate uptake, flagellar motility, pathogenicity and pH regulation have been proposed for the Na +requirement of marine or pathogenic bacteria. [3][4][5][6][7][8] All these physiological functions are dependent on the sodium motive force (DpNa).…”