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Regulation of Expression of Oxacillin-Inducible Methionine Sulfoxide Reductases in Staphylococcus aureus.

Baum KR, Ahmad Z, Singh VK - Int J Microbiol (2015)

Bottom Line: Cell wall-active antibiotics cause induction of a locus that leads to elevated synthesis of two methionine sulfoxide reductases (MsrA1 and MsrB) in Staphylococcus aureus.These reporter strains were cultured in TSB and the cellular levels of β-galactosidase activity in these cultures were assayed during different growth phases. β-galactosidase activity assays demonstrated that the lack of MsrA1, MsrB, and SigB upregulated the msrA1/msrB promoter in S. aureus strain SH1000.The data suggest that the msrA1/msrB locus, in part, is negatively regulated by MsrA1, MsrB, and SigB in S. aureus.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA.

ABSTRACT
Cell wall-active antibiotics cause induction of a locus that leads to elevated synthesis of two methionine sulfoxide reductases (MsrA1 and MsrB) in Staphylococcus aureus. To understand the regulation of this locus, reporter strains were constructed by integrating a DNA fragment consisting of the msrA1/msrB promoter in front of a promoterless lacZ gene in the chromosome of wild-type and MsrA1-, MsrB-, MsrA1/MsrB-, and SigB-deficient methicillin-sensitive S. aureus strain SH1000 and methicillin-resistant S. aureus strain COL. These reporter strains were cultured in TSB and the cellular levels of β-galactosidase activity in these cultures were assayed during different growth phases. β-galactosidase activity assays demonstrated that the lack of MsrA1, MsrB, and SigB upregulated the msrA1/msrB promoter in S. aureus strain SH1000. In S. aureus strain COL, the highest level of β-galactosidase activity was observed under the conditions when both MsrA1 and MsrB proteins were absent. The data suggest that the msrA1/msrB locus, in part, is negatively regulated by MsrA1, MsrB, and SigB in S. aureus.

No MeSH data available.


Related in: MedlinePlus

Analysis of msrA1/msrB promoter-lacZ fusion in wild-type and msrA1-msrB double mutant of S. aureus COL in response to oxacillin. At OD600 = 0.5, cells were treated with oxacillin for 2 h and the β-galactosidase activity levels were measured. Values indicate averages of data from at least three independent experiments ± standard error (∗ significant between samples with and without oxacillin at p ≤ 0.05; † significant between oxacillin treated wild-type and the oxacillin treated msrA1-msrB double mutant at p ≤ 0.05).
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fig6: Analysis of msrA1/msrB promoter-lacZ fusion in wild-type and msrA1-msrB double mutant of S. aureus COL in response to oxacillin. At OD600 = 0.5, cells were treated with oxacillin for 2 h and the β-galactosidase activity levels were measured. Values indicate averages of data from at least three independent experiments ± standard error (∗ significant between samples with and without oxacillin at p ≤ 0.05; † significant between oxacillin treated wild-type and the oxacillin treated msrA1-msrB double mutant at p ≤ 0.05).

Mentions: While studying the regulation of the msrA1/msrB locus in a methicillin-resistant S. aureus strain COL, oxacillin was added during the growth of the msrA1/msrB promoter-lacZ reporter to investigate any magnification of the regulation. In these studies, while an increased lacZ expression was observed in wild-type S. aureus strain COL after oxacillin treatment, a more dramatic increase in the lacZ expression in response to oxacillin was seen in MsrA1-MsrB-deficient COL (Figure 6).


Regulation of Expression of Oxacillin-Inducible Methionine Sulfoxide Reductases in Staphylococcus aureus.

Baum KR, Ahmad Z, Singh VK - Int J Microbiol (2015)

Analysis of msrA1/msrB promoter-lacZ fusion in wild-type and msrA1-msrB double mutant of S. aureus COL in response to oxacillin. At OD600 = 0.5, cells were treated with oxacillin for 2 h and the β-galactosidase activity levels were measured. Values indicate averages of data from at least three independent experiments ± standard error (∗ significant between samples with and without oxacillin at p ≤ 0.05; † significant between oxacillin treated wild-type and the oxacillin treated msrA1-msrB double mutant at p ≤ 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4592908&req=5

fig6: Analysis of msrA1/msrB promoter-lacZ fusion in wild-type and msrA1-msrB double mutant of S. aureus COL in response to oxacillin. At OD600 = 0.5, cells were treated with oxacillin for 2 h and the β-galactosidase activity levels were measured. Values indicate averages of data from at least three independent experiments ± standard error (∗ significant between samples with and without oxacillin at p ≤ 0.05; † significant between oxacillin treated wild-type and the oxacillin treated msrA1-msrB double mutant at p ≤ 0.05).
Mentions: While studying the regulation of the msrA1/msrB locus in a methicillin-resistant S. aureus strain COL, oxacillin was added during the growth of the msrA1/msrB promoter-lacZ reporter to investigate any magnification of the regulation. In these studies, while an increased lacZ expression was observed in wild-type S. aureus strain COL after oxacillin treatment, a more dramatic increase in the lacZ expression in response to oxacillin was seen in MsrA1-MsrB-deficient COL (Figure 6).

Bottom Line: Cell wall-active antibiotics cause induction of a locus that leads to elevated synthesis of two methionine sulfoxide reductases (MsrA1 and MsrB) in Staphylococcus aureus.These reporter strains were cultured in TSB and the cellular levels of β-galactosidase activity in these cultures were assayed during different growth phases. β-galactosidase activity assays demonstrated that the lack of MsrA1, MsrB, and SigB upregulated the msrA1/msrB promoter in S. aureus strain SH1000.The data suggest that the msrA1/msrB locus, in part, is negatively regulated by MsrA1, MsrB, and SigB in S. aureus.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA.

ABSTRACT
Cell wall-active antibiotics cause induction of a locus that leads to elevated synthesis of two methionine sulfoxide reductases (MsrA1 and MsrB) in Staphylococcus aureus. To understand the regulation of this locus, reporter strains were constructed by integrating a DNA fragment consisting of the msrA1/msrB promoter in front of a promoterless lacZ gene in the chromosome of wild-type and MsrA1-, MsrB-, MsrA1/MsrB-, and SigB-deficient methicillin-sensitive S. aureus strain SH1000 and methicillin-resistant S. aureus strain COL. These reporter strains were cultured in TSB and the cellular levels of β-galactosidase activity in these cultures were assayed during different growth phases. β-galactosidase activity assays demonstrated that the lack of MsrA1, MsrB, and SigB upregulated the msrA1/msrB promoter in S. aureus strain SH1000. In S. aureus strain COL, the highest level of β-galactosidase activity was observed under the conditions when both MsrA1 and MsrB proteins were absent. The data suggest that the msrA1/msrB locus, in part, is negatively regulated by MsrA1, MsrB, and SigB in S. aureus.

No MeSH data available.


Related in: MedlinePlus