Cyanide Production by <italic toggle="yes">Chromobacterium piscinae</italic> Shields It from <italic toggle="yes">Bdellovibrio bacteriovorus</italic> HD100 Predation

ABSTRACT Predation of Chromobacterium piscinae by Bdellovibrio bacteriovorus HD100 was inhibited in dilute nutrient broth (DNB) but not in HEPES. Experiments showed that the effector responsible was present in the medium, as cell-free supernatants retained the ability to inhibit predation, and that...

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Autores principales:	Wonsik Mun, Heeun Kwon, Hansol Im, Seong Yeol Choi, Ajay K. Monnappa, Robert J. Mitchell
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2017
Materias:	Bdellovibrio bacteriovorus HD100 Chromobacterium piscinae cyanide predation violacein Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/c6d64d249a5648cd80dac68908869e75
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spelling	oai:doaj.org-article:c6d64d249a5648cd80dac68908869e752021-11-15T15:51:55ZCyanide Production by <italic toggle="yes">Chromobacterium piscinae</italic> Shields It from <italic toggle="yes">Bdellovibrio bacteriovorus</italic> HD100 Predation10.1128/mBio.01370-172150-7511https://doaj.org/article/c6d64d249a5648cd80dac68908869e752017-12-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01370-17https://doaj.org/toc/2150-7511ABSTRACT Predation of Chromobacterium piscinae by Bdellovibrio bacteriovorus HD100 was inhibited in dilute nutrient broth (DNB) but not in HEPES. Experiments showed that the effector responsible was present in the medium, as cell-free supernatants retained the ability to inhibit predation, and that the effector was not toxic to B. bacteriovorus. Violacein, a bisindole secondary metabolite produced by C. piscinae, was not responsible. Further characterization of C. piscinae found that this species produces sufficient concentrations of cyanide (202 µM) when grown in DNB to inhibit the predatory activity of B. bacteriovorus, but that in HEPES, the cyanide concentrations were negligible (19 µM). The antagonistic role of cyanide was further confirmed, as the addition of hydroxocobalamin, which chelates cyanide, allowed predation to proceed. The activity of cyanide against B. bacteriovorus was found to be twofold, depending on the life cycle stage of this predator. For the attack-phase predatory cells, cyanide caused the cells to lose motility and tumble, while for intraperiplasmic predators, development and lysis of the prey cell were halted. These findings suggest that cyanogenesis in nature may be employed by the bacterial strains that produce this compound to prevent and reduce their predation by B. bacteriovorus. IMPORTANCE Bacterial predators actively attack, kill, and enter the periplasm of susceptible Gram-negative bacteria, where they consume the prey cell components. To date, the activity of B. bacteriovorus HD100 has been demonstrated against more than 100 human pathogens. As such, this strain and others are being considered as potential alternatives or supplements to conventional antibiotics. However, the production of secondary metabolites by prey bacteria is known to mitigate, and even abolish, predation by bacterivorous nematodes and protists. With the exception of indole, which was shown to inhibit predation, the effects of bacterial secondary metabolites on B. bacteriovorus and its activities have not been considered. Consequently, we undertook this study to better understand the mechanisms that bacterial strains employ to inhibit predation by B. bacteriovorus HD100. We report here that cyanogenic bacterial strains can inhibit predation and show that cyanide affects both attack-phase predators and those within prey, i.e., in the bdelloplast.Wonsik MunHeeun KwonHansol ImSeong Yeol ChoiAjay K. MonnappaRobert J. MitchellAmerican Society for MicrobiologyarticleBdellovibrio bacteriovorus HD100Chromobacterium piscinaecyanidepredationviolaceinMicrobiologyQR1-502ENmBio, Vol 8, Iss 6 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Bdellovibrio bacteriovorus HD100 Chromobacterium piscinae cyanide predation violacein Microbiology QR1-502
spellingShingle	Bdellovibrio bacteriovorus HD100 Chromobacterium piscinae cyanide predation violacein Microbiology QR1-502 Wonsik Mun Heeun Kwon Hansol Im Seong Yeol Choi Ajay K. Monnappa Robert J. Mitchell Cyanide Production by <italic toggle="yes">Chromobacterium piscinae</italic> Shields It from <italic toggle="yes">Bdellovibrio bacteriovorus</italic> HD100 Predation
description	ABSTRACT Predation of Chromobacterium piscinae by Bdellovibrio bacteriovorus HD100 was inhibited in dilute nutrient broth (DNB) but not in HEPES. Experiments showed that the effector responsible was present in the medium, as cell-free supernatants retained the ability to inhibit predation, and that the effector was not toxic to B. bacteriovorus. Violacein, a bisindole secondary metabolite produced by C. piscinae, was not responsible. Further characterization of C. piscinae found that this species produces sufficient concentrations of cyanide (202 µM) when grown in DNB to inhibit the predatory activity of B. bacteriovorus, but that in HEPES, the cyanide concentrations were negligible (19 µM). The antagonistic role of cyanide was further confirmed, as the addition of hydroxocobalamin, which chelates cyanide, allowed predation to proceed. The activity of cyanide against B. bacteriovorus was found to be twofold, depending on the life cycle stage of this predator. For the attack-phase predatory cells, cyanide caused the cells to lose motility and tumble, while for intraperiplasmic predators, development and lysis of the prey cell were halted. These findings suggest that cyanogenesis in nature may be employed by the bacterial strains that produce this compound to prevent and reduce their predation by B. bacteriovorus. IMPORTANCE Bacterial predators actively attack, kill, and enter the periplasm of susceptible Gram-negative bacteria, where they consume the prey cell components. To date, the activity of B. bacteriovorus HD100 has been demonstrated against more than 100 human pathogens. As such, this strain and others are being considered as potential alternatives or supplements to conventional antibiotics. However, the production of secondary metabolites by prey bacteria is known to mitigate, and even abolish, predation by bacterivorous nematodes and protists. With the exception of indole, which was shown to inhibit predation, the effects of bacterial secondary metabolites on B. bacteriovorus and its activities have not been considered. Consequently, we undertook this study to better understand the mechanisms that bacterial strains employ to inhibit predation by B. bacteriovorus HD100. We report here that cyanogenic bacterial strains can inhibit predation and show that cyanide affects both attack-phase predators and those within prey, i.e., in the bdelloplast.
format	article
author	Wonsik Mun Heeun Kwon Hansol Im Seong Yeol Choi Ajay K. Monnappa Robert J. Mitchell
author_facet	Wonsik Mun Heeun Kwon Hansol Im Seong Yeol Choi Ajay K. Monnappa Robert J. Mitchell
author_sort	Wonsik Mun
title	Cyanide Production by <italic toggle="yes">Chromobacterium piscinae</italic> Shields It from <italic toggle="yes">Bdellovibrio bacteriovorus</italic> HD100 Predation
title_short	Cyanide Production by <italic toggle="yes">Chromobacterium piscinae</italic> Shields It from <italic toggle="yes">Bdellovibrio bacteriovorus</italic> HD100 Predation
title_full	Cyanide Production by <italic toggle="yes">Chromobacterium piscinae</italic> Shields It from <italic toggle="yes">Bdellovibrio bacteriovorus</italic> HD100 Predation
title_fullStr	Cyanide Production by <italic toggle="yes">Chromobacterium piscinae</italic> Shields It from <italic toggle="yes">Bdellovibrio bacteriovorus</italic> HD100 Predation
title_full_unstemmed	Cyanide Production by <italic toggle="yes">Chromobacterium piscinae</italic> Shields It from <italic toggle="yes">Bdellovibrio bacteriovorus</italic> HD100 Predation
title_sort	cyanide production by <italic toggle="yes">chromobacterium piscinae</italic> shields it from <italic toggle="yes">bdellovibrio bacteriovorus</italic> hd100 predation
publisher	American Society for Microbiology
publishDate	2017
url	https://doaj.org/article/c6d64d249a5648cd80dac68908869e75
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Cyanide Production by <italic toggle="yes">Chromobacterium piscinae</italic> Shields It from <italic toggle="yes">Bdellovibrio bacteriovorus</italic> HD100 Predation

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