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The Agr communication system provides a benefit to the populations of Listeria monocytogenes in soil.

Vivant AL, Garmyn D, Gal L, Piveteau P - Front Cell Infect Microbiol (2014)

Bottom Line: Alteration of the ability to communicate, either by deletion of the gene coding the response regulator AgrA (response-negative mutant) or the signal pro-peptide AgrD (signal-negative mutant), did not affect population dynamics in soil that had been sterilized but survival was altered in biotic soil suggesting that the Agr system of L. monocytogenes was involved to face the complex soil biotic environment.These results showed that the ability to respond to Agr communication provided a benefit to listerial cells to compete.These results might also indicate that in soil, the Agr system controls private goods rather than public goods.

View Article: PubMed Central - PubMed

Affiliation: Unités Mixtes de Recherche1347 Agroécologie, Université de Bourgogne Dijon, France ; Institut National de la Recherche Agronomique, Unités Mixtes de Recherche1347 Agroécologie Dijon, France.

ABSTRACT
In this study, we investigated whether the Agr communication system of the pathogenic bacterium Listeria monocytogenes was involved in adaptation and competitiveness in soil. Alteration of the ability to communicate, either by deletion of the gene coding the response regulator AgrA (response-negative mutant) or the signal pro-peptide AgrD (signal-negative mutant), did not affect population dynamics in soil that had been sterilized but survival was altered in biotic soil suggesting that the Agr system of L. monocytogenes was involved to face the complex soil biotic environment. This was confirmed by a set of co-incubation experiments. The fitness of the response-negative mutant was lower either in the presence or absence of the parental strain but the fitness of the signal-negative mutant depended on the strain with which it was co-incubated. The survival of the signal-negative mutant was higher when co-cultured with the parental strain than when co-cultured with the response-negative mutant. These results showed that the ability to respond to Agr communication provided a benefit to listerial cells to compete. These results might also indicate that in soil, the Agr system controls private goods rather than public goods.

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Dynamics of (A) the parental strain, (B) the response-negative mutant and (C) the signal-negative mutant populations in sterilized soil microcosms. (♦) Single culture, () co-culture with the parental strain, () co-culture with the response-negative mutant, () co-culture with the signal-negative mutant. Error bars represent the standard deviation from three replicate samples value.
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Figure 3: Dynamics of (A) the parental strain, (B) the response-negative mutant and (C) the signal-negative mutant populations in sterilized soil microcosms. (♦) Single culture, () co-culture with the parental strain, () co-culture with the response-negative mutant, () co-culture with the signal-negative mutant. Error bars represent the standard deviation from three replicate samples value.

Mentions: As shown in Figure 3, in sterilized soil microcosms, colonization profiles were similar for all strains whether they had been cultured as a single strain or with a partner. Moreover, variations of the CI were not significant (ANOVA, P > 0.05) (Table 2). This is consistent with the results described above and confirms that in sterilized soil, in the absence of biotic pressure, inactivation of the Agr system does not alter the competitiveness of the mutants. Considering that in sterilized soil, cell density is higher than in biotic soil (about 4 log) and that scavenging of signal molecules is more limited, accumulation of signal molecules is expected. This suggests that, under these experimental conditions, the AgrA-controlled features may not be essential for growth.


The Agr communication system provides a benefit to the populations of Listeria monocytogenes in soil.

Vivant AL, Garmyn D, Gal L, Piveteau P - Front Cell Infect Microbiol (2014)

Dynamics of (A) the parental strain, (B) the response-negative mutant and (C) the signal-negative mutant populations in sterilized soil microcosms. (♦) Single culture, () co-culture with the parental strain, () co-culture with the response-negative mutant, () co-culture with the signal-negative mutant. Error bars represent the standard deviation from three replicate samples value.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4222237&req=5

Figure 3: Dynamics of (A) the parental strain, (B) the response-negative mutant and (C) the signal-negative mutant populations in sterilized soil microcosms. (♦) Single culture, () co-culture with the parental strain, () co-culture with the response-negative mutant, () co-culture with the signal-negative mutant. Error bars represent the standard deviation from three replicate samples value.
Mentions: As shown in Figure 3, in sterilized soil microcosms, colonization profiles were similar for all strains whether they had been cultured as a single strain or with a partner. Moreover, variations of the CI were not significant (ANOVA, P > 0.05) (Table 2). This is consistent with the results described above and confirms that in sterilized soil, in the absence of biotic pressure, inactivation of the Agr system does not alter the competitiveness of the mutants. Considering that in sterilized soil, cell density is higher than in biotic soil (about 4 log) and that scavenging of signal molecules is more limited, accumulation of signal molecules is expected. This suggests that, under these experimental conditions, the AgrA-controlled features may not be essential for growth.

Bottom Line: Alteration of the ability to communicate, either by deletion of the gene coding the response regulator AgrA (response-negative mutant) or the signal pro-peptide AgrD (signal-negative mutant), did not affect population dynamics in soil that had been sterilized but survival was altered in biotic soil suggesting that the Agr system of L. monocytogenes was involved to face the complex soil biotic environment.These results showed that the ability to respond to Agr communication provided a benefit to listerial cells to compete.These results might also indicate that in soil, the Agr system controls private goods rather than public goods.

View Article: PubMed Central - PubMed

Affiliation: Unités Mixtes de Recherche1347 Agroécologie, Université de Bourgogne Dijon, France ; Institut National de la Recherche Agronomique, Unités Mixtes de Recherche1347 Agroécologie Dijon, France.

ABSTRACT
In this study, we investigated whether the Agr communication system of the pathogenic bacterium Listeria monocytogenes was involved in adaptation and competitiveness in soil. Alteration of the ability to communicate, either by deletion of the gene coding the response regulator AgrA (response-negative mutant) or the signal pro-peptide AgrD (signal-negative mutant), did not affect population dynamics in soil that had been sterilized but survival was altered in biotic soil suggesting that the Agr system of L. monocytogenes was involved to face the complex soil biotic environment. This was confirmed by a set of co-incubation experiments. The fitness of the response-negative mutant was lower either in the presence or absence of the parental strain but the fitness of the signal-negative mutant depended on the strain with which it was co-incubated. The survival of the signal-negative mutant was higher when co-cultured with the parental strain than when co-cultured with the response-negative mutant. These results showed that the ability to respond to Agr communication provided a benefit to listerial cells to compete. These results might also indicate that in soil, the Agr system controls private goods rather than public goods.

Show MeSH
Related in: MedlinePlus