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Bacillus cereus ATCC 14579 RpoN (Sigma 54) Is a Pleiotropic Regulator of Growth, Carbohydrate Metabolism, Motility, Biofilm Formation and Toxin Production.

Hayrapetyan H, Tempelaars M, Nierop Groot M, Abee T - PLoS ONE (2015)

Bottom Line: The mutant was impaired in many different cellular functions including low temperature and anaerobic growth, carbohydrate metabolism, sporulation and toxin production.Comparative transcriptome analysis of cells harvested at selected time points during growth in aerated and static conditions in BHI revealed large differences in gene expression associated with loss of phenotypes, including significant down regulation of genes in the mutant encoding enzymes involved in degradation of branched chain amino acids, carbohydrate transport and metabolism, flagella synthesis and virulence factors.Our study provides evidence for a pleiotropic role of Sigma 54 in B. cereus supporting its adaptive response and survival in a range of conditions and environments.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Food Microbiology, Bornse Weilanden 9, 6708 WG Wageningen University, Wageningen, The Netherlands; Top Institute of Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA, Wageningen, The Netherlands.

ABSTRACT
Sigma 54 is a transcriptional regulator predicted to play a role in physical interaction of bacteria with their environment, including virulence and biofilm formation. In order to study the role of Sigma 54 in Bacillus cereus, a comparative transcriptome and phenotypic study was performed using B. cereus ATCC 14579 WT, a markerless rpoN deletion mutant, and its complemented strain. The mutant was impaired in many different cellular functions including low temperature and anaerobic growth, carbohydrate metabolism, sporulation and toxin production. Additionally, the mutant showed lack of motility and biofilm formation at air-liquid interphase, and this correlated with absence of flagella, as flagella staining showed only WT and complemented strain to be highly flagellated. Comparative transcriptome analysis of cells harvested at selected time points during growth in aerated and static conditions in BHI revealed large differences in gene expression associated with loss of phenotypes, including significant down regulation of genes in the mutant encoding enzymes involved in degradation of branched chain amino acids, carbohydrate transport and metabolism, flagella synthesis and virulence factors. Our study provides evidence for a pleiotropic role of Sigma 54 in B. cereus supporting its adaptive response and survival in a range of conditions and environments.

No MeSH data available.


Related in: MedlinePlus

Toxin production.Production of non-hemolytic toxin (NheA) measured in BHI at 30°C with aeration at mid-exponential (OD 600 nm = 0.2) and end-exponential (OD 600 nm = 1) growth phases, and at mid-exponential (OD 600 nm = 0.2) phase during static growth.
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pone.0134872.g007: Toxin production.Production of non-hemolytic toxin (NheA) measured in BHI at 30°C with aeration at mid-exponential (OD 600 nm = 0.2) and end-exponential (OD 600 nm = 1) growth phases, and at mid-exponential (OD 600 nm = 0.2) phase during static growth.

Mentions: Production of non-haemolytic enterotoxin lytic component L2 (NheA) was measured in aerated (mid-exponential and end-exponential) and static (mid-exponential) growing conditions. Toxin levels for the rpoN mutant were significantly lower compared to the WT, with ratios of WT/ΔrpoN levels varying between 2.9 and 4 depending on the condition tested (Fig 7). The toxin level was partially restored to that of the WT for the complemented mutant strain.


Bacillus cereus ATCC 14579 RpoN (Sigma 54) Is a Pleiotropic Regulator of Growth, Carbohydrate Metabolism, Motility, Biofilm Formation and Toxin Production.

Hayrapetyan H, Tempelaars M, Nierop Groot M, Abee T - PLoS ONE (2015)

Toxin production.Production of non-hemolytic toxin (NheA) measured in BHI at 30°C with aeration at mid-exponential (OD 600 nm = 0.2) and end-exponential (OD 600 nm = 1) growth phases, and at mid-exponential (OD 600 nm = 0.2) phase during static growth.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4524646&req=5

pone.0134872.g007: Toxin production.Production of non-hemolytic toxin (NheA) measured in BHI at 30°C with aeration at mid-exponential (OD 600 nm = 0.2) and end-exponential (OD 600 nm = 1) growth phases, and at mid-exponential (OD 600 nm = 0.2) phase during static growth.
Mentions: Production of non-haemolytic enterotoxin lytic component L2 (NheA) was measured in aerated (mid-exponential and end-exponential) and static (mid-exponential) growing conditions. Toxin levels for the rpoN mutant were significantly lower compared to the WT, with ratios of WT/ΔrpoN levels varying between 2.9 and 4 depending on the condition tested (Fig 7). The toxin level was partially restored to that of the WT for the complemented mutant strain.

Bottom Line: The mutant was impaired in many different cellular functions including low temperature and anaerobic growth, carbohydrate metabolism, sporulation and toxin production.Comparative transcriptome analysis of cells harvested at selected time points during growth in aerated and static conditions in BHI revealed large differences in gene expression associated with loss of phenotypes, including significant down regulation of genes in the mutant encoding enzymes involved in degradation of branched chain amino acids, carbohydrate transport and metabolism, flagella synthesis and virulence factors.Our study provides evidence for a pleiotropic role of Sigma 54 in B. cereus supporting its adaptive response and survival in a range of conditions and environments.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Food Microbiology, Bornse Weilanden 9, 6708 WG Wageningen University, Wageningen, The Netherlands; Top Institute of Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA, Wageningen, The Netherlands.

ABSTRACT
Sigma 54 is a transcriptional regulator predicted to play a role in physical interaction of bacteria with their environment, including virulence and biofilm formation. In order to study the role of Sigma 54 in Bacillus cereus, a comparative transcriptome and phenotypic study was performed using B. cereus ATCC 14579 WT, a markerless rpoN deletion mutant, and its complemented strain. The mutant was impaired in many different cellular functions including low temperature and anaerobic growth, carbohydrate metabolism, sporulation and toxin production. Additionally, the mutant showed lack of motility and biofilm formation at air-liquid interphase, and this correlated with absence of flagella, as flagella staining showed only WT and complemented strain to be highly flagellated. Comparative transcriptome analysis of cells harvested at selected time points during growth in aerated and static conditions in BHI revealed large differences in gene expression associated with loss of phenotypes, including significant down regulation of genes in the mutant encoding enzymes involved in degradation of branched chain amino acids, carbohydrate transport and metabolism, flagella synthesis and virulence factors. Our study provides evidence for a pleiotropic role of Sigma 54 in B. cereus supporting its adaptive response and survival in a range of conditions and environments.

No MeSH data available.


Related in: MedlinePlus