Limits...
Cyclic di-GMP-dependent signaling pathways in the pathogenic Firmicute Listeria monocytogenes.

Chen LH, Köseoğlu VK, Güvener ZT, Myers-Morales T, Reed JM, D'Orazio SE, Miller KW, Gomelsky M - PLoS Pathog. (2014)

Bottom Line: The last gene of the cluster encodes the fourth listerial GGDEF domain protein, PssE, that functions as an I-site c-di-GMP receptor essential for exopolysaccharide synthesis.The c-di-GMP-inducible exopolysaccharide causes cell aggregation in minimal medium and impairs bacterial migration in semi-solid agar, however, it does not promote biofilm formation on abiotic surfaces.The exopolysaccharide and another, as yet unknown c-di-GMP-dependent target, drastically decrease listerial invasiveness in enterocytes in vitro, and lower pathogen load in the liver and gallbladder of mice infected via an oral route, which suggests that elevated c-di-GMP levels play an overall negative role in listerial virulence.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, United States of America.

ABSTRACT
We characterized key components and major targets of the c-di-GMP signaling pathways in the foodborne pathogen Listeria monocytogenes, identified a new c-di-GMP-inducible exopolysaccharide responsible for motility inhibition, cell aggregation, and enhanced tolerance to disinfectants and desiccation, and provided first insights into the role of c-di-GMP signaling in listerial virulence. Genome-wide genetic and biochemical analyses of c-di-GMP signaling pathways revealed that L. monocytogenes has three GGDEF domain proteins, DgcA (Lmo1911), DgcB (Lmo1912) and DgcC (Lmo2174), that possess diguanylate cyclase activity, and three EAL domain proteins, PdeB (Lmo0131), PdeC (Lmo1914) and PdeD (Lmo0111), that possess c-di-GMP phosphodiesterase activity. Deletion of all phosphodiesterase genes (ΔpdeB/C/D) or expression of a heterologous diguanylate cyclase stimulated production of a previously unknown exopolysaccharide. The synthesis of this exopolysaccharide was attributed to the pssA-E (lmo0527-0531) gene cluster. The last gene of the cluster encodes the fourth listerial GGDEF domain protein, PssE, that functions as an I-site c-di-GMP receptor essential for exopolysaccharide synthesis. The c-di-GMP-inducible exopolysaccharide causes cell aggregation in minimal medium and impairs bacterial migration in semi-solid agar, however, it does not promote biofilm formation on abiotic surfaces. The exopolysaccharide also greatly enhances bacterial tolerance to commonly used disinfectants as well as desiccation, which may contribute to survival of L. monocytogenes on contaminated food products and in food-processing facilities. The exopolysaccharide and another, as yet unknown c-di-GMP-dependent target, drastically decrease listerial invasiveness in enterocytes in vitro, and lower pathogen load in the liver and gallbladder of mice infected via an oral route, which suggests that elevated c-di-GMP levels play an overall negative role in listerial virulence.

Show MeSH

Related in: MedlinePlus

DGC activities of the L. monocytogenes proteins DgcA-C.A: Inhibition of motility in semi-solid (0.25%) agar of strain MG1655 by L. monocytogenes DgcA (plasmid pBAD-dgcA), DgcB (pBAD-dgcB) and DgcC (pBAD-dgcC) is indicative of their DGC activities. DgcA-C were expressed from the vector pBAD/Myc-His-C (pBAD). LB agar contained 0.1% arabinose. B: Congo red staining of the fimbriae producing strain BL21(DE3) caused by L. monocytogenes DgcA, DgcB and DgcC is indicative of their DGC activities. LB agar contained 0.001% arabinose.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4125290&req=5

ppat-1004301-g003: DGC activities of the L. monocytogenes proteins DgcA-C.A: Inhibition of motility in semi-solid (0.25%) agar of strain MG1655 by L. monocytogenes DgcA (plasmid pBAD-dgcA), DgcB (pBAD-dgcB) and DgcC (pBAD-dgcC) is indicative of their DGC activities. DgcA-C were expressed from the vector pBAD/Myc-His-C (pBAD). LB agar contained 0.1% arabinose. B: Congo red staining of the fimbriae producing strain BL21(DE3) caused by L. monocytogenes DgcA, DgcB and DgcC is indicative of their DGC activities. LB agar contained 0.001% arabinose.

Mentions: The functionality of putative L. monocytogenes DGC proteins was assessed by monitoring swim zone sizes in semi-solid agar. The three dgc genes were cloned into the pBAD/Myc-His vector under the control of an arabinose-inducible promoter. Each of the three dgc genes decreased, to various degrees, the sizes of the swim zones of strain MG1655, which is highly motile in the absence of heterologous DGCs (Fig. 3A).


Cyclic di-GMP-dependent signaling pathways in the pathogenic Firmicute Listeria monocytogenes.

Chen LH, Köseoğlu VK, Güvener ZT, Myers-Morales T, Reed JM, D'Orazio SE, Miller KW, Gomelsky M - PLoS Pathog. (2014)

DGC activities of the L. monocytogenes proteins DgcA-C.A: Inhibition of motility in semi-solid (0.25%) agar of strain MG1655 by L. monocytogenes DgcA (plasmid pBAD-dgcA), DgcB (pBAD-dgcB) and DgcC (pBAD-dgcC) is indicative of their DGC activities. DgcA-C were expressed from the vector pBAD/Myc-His-C (pBAD). LB agar contained 0.1% arabinose. B: Congo red staining of the fimbriae producing strain BL21(DE3) caused by L. monocytogenes DgcA, DgcB and DgcC is indicative of their DGC activities. LB agar contained 0.001% arabinose.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4125290&req=5

ppat-1004301-g003: DGC activities of the L. monocytogenes proteins DgcA-C.A: Inhibition of motility in semi-solid (0.25%) agar of strain MG1655 by L. monocytogenes DgcA (plasmid pBAD-dgcA), DgcB (pBAD-dgcB) and DgcC (pBAD-dgcC) is indicative of their DGC activities. DgcA-C were expressed from the vector pBAD/Myc-His-C (pBAD). LB agar contained 0.1% arabinose. B: Congo red staining of the fimbriae producing strain BL21(DE3) caused by L. monocytogenes DgcA, DgcB and DgcC is indicative of their DGC activities. LB agar contained 0.001% arabinose.
Mentions: The functionality of putative L. monocytogenes DGC proteins was assessed by monitoring swim zone sizes in semi-solid agar. The three dgc genes were cloned into the pBAD/Myc-His vector under the control of an arabinose-inducible promoter. Each of the three dgc genes decreased, to various degrees, the sizes of the swim zones of strain MG1655, which is highly motile in the absence of heterologous DGCs (Fig. 3A).

Bottom Line: The last gene of the cluster encodes the fourth listerial GGDEF domain protein, PssE, that functions as an I-site c-di-GMP receptor essential for exopolysaccharide synthesis.The c-di-GMP-inducible exopolysaccharide causes cell aggregation in minimal medium and impairs bacterial migration in semi-solid agar, however, it does not promote biofilm formation on abiotic surfaces.The exopolysaccharide and another, as yet unknown c-di-GMP-dependent target, drastically decrease listerial invasiveness in enterocytes in vitro, and lower pathogen load in the liver and gallbladder of mice infected via an oral route, which suggests that elevated c-di-GMP levels play an overall negative role in listerial virulence.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, United States of America.

ABSTRACT
We characterized key components and major targets of the c-di-GMP signaling pathways in the foodborne pathogen Listeria monocytogenes, identified a new c-di-GMP-inducible exopolysaccharide responsible for motility inhibition, cell aggregation, and enhanced tolerance to disinfectants and desiccation, and provided first insights into the role of c-di-GMP signaling in listerial virulence. Genome-wide genetic and biochemical analyses of c-di-GMP signaling pathways revealed that L. monocytogenes has three GGDEF domain proteins, DgcA (Lmo1911), DgcB (Lmo1912) and DgcC (Lmo2174), that possess diguanylate cyclase activity, and three EAL domain proteins, PdeB (Lmo0131), PdeC (Lmo1914) and PdeD (Lmo0111), that possess c-di-GMP phosphodiesterase activity. Deletion of all phosphodiesterase genes (ΔpdeB/C/D) or expression of a heterologous diguanylate cyclase stimulated production of a previously unknown exopolysaccharide. The synthesis of this exopolysaccharide was attributed to the pssA-E (lmo0527-0531) gene cluster. The last gene of the cluster encodes the fourth listerial GGDEF domain protein, PssE, that functions as an I-site c-di-GMP receptor essential for exopolysaccharide synthesis. The c-di-GMP-inducible exopolysaccharide causes cell aggregation in minimal medium and impairs bacterial migration in semi-solid agar, however, it does not promote biofilm formation on abiotic surfaces. The exopolysaccharide also greatly enhances bacterial tolerance to commonly used disinfectants as well as desiccation, which may contribute to survival of L. monocytogenes on contaminated food products and in food-processing facilities. The exopolysaccharide and another, as yet unknown c-di-GMP-dependent target, drastically decrease listerial invasiveness in enterocytes in vitro, and lower pathogen load in the liver and gallbladder of mice infected via an oral route, which suggests that elevated c-di-GMP levels play an overall negative role in listerial virulence.

Show MeSH
Related in: MedlinePlus