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SaeRS-dependent inhibition of biofilm formation in Staphylococcus aureus Newman.

Cue D, Junecko JM, Lei MG, Blevins JS, Smeltzer MS, Lee CY - PLoS ONE (2015)

Bottom Line: The inhibitory protein was found to affect the attachment step in biofilm formation, but had no effect on preformed biofilms.Although a number of candidate proteins were identified, none were found to be the actual inhibitor.RNA-Seq results indicated that sae regulates many genes that may affect biofilm formation by Newman.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, United States of America.

ABSTRACT
The SaeRS two-component regulatory system of Staphylococcus aureus is known to affect the expression of many genes. The SaeS protein is the histidine kinase responsible for phosphorylation of the response regulator SaeR. In S. aureus Newman, the sae system is constitutively expressed due to a point mutation in saeS, relative to other S. aureus strains, which results in substitution of proline for leucine at amino acid 18. Strain Newman is unable to form a robust biofilm and we report here that the biofilm-deficient phenotype is due to the saeSP allele. Replacement of the Newman saeSP with saeSL, or deletion of saeRS, resulted in a biofilm-proficient phenotype. Newman culture supernatants were observed to inhibit biofilm formation by other S. aureus strains, but did not affect biofilm formation by S. epidermidis. Culture supernatants of Newman saeSL or Newman ΔsaeRS had no significant effect on biofilm formation. The inhibitory factor was inactivated by incubation with proteinase K, but survived heating, indicating that the inhibitory protein is heat-stable. The inhibitory protein was found to affect the attachment step in biofilm formation, but had no effect on preformed biofilms. Replacement of saeSL with saeSP in the biofilm-proficient S. aureus USA300 FPR3757 resulted in the loss of biofilm formation. Culture supernatants of USA300 FPR3757 saeSP, did not inhibit biofilm formation by other staphylococci, suggesting that the inhibitory factor is produced but not secreted in the mutant strain. A number of biochemical methods were utilized to isolate the inhibitory protein. Although a number of candidate proteins were identified, none were found to be the actual inhibitor. In an effort to reduce the number of potential inhibitory genes, RNA-Seq analyses were done with wild-type strain Newman and the saeSL and ΔsaeRS mutants. RNA-Seq results indicated that sae regulates many genes that may affect biofilm formation by Newman.

No MeSH data available.


Related in: MedlinePlus

The biofilm inhibitory protein limits biofilm in S. aureus but not S. epidermidis strains.Culture supernatants from strain Newman or the ΔsaePQRS::kan mutant were added to biofilm medium and anti-biofilm activity was tested against the bacterial strains listed to the left of the figure. “Medium” indicates that sterile medium was added in place of culture supernatant.
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pone.0123027.g005: The biofilm inhibitory protein limits biofilm in S. aureus but not S. epidermidis strains.Culture supernatants from strain Newman or the ΔsaePQRS::kan mutant were added to biofilm medium and anti-biofilm activity was tested against the bacterial strains listed to the left of the figure. “Medium” indicates that sterile medium was added in place of culture supernatant.

Mentions: The results above indicate that a secreted protein produced by strain Newman inhibited biofilm formation by strain UAMS-1 when added to biofilm medium at the time of inoculation. To test anti-biofilm activity of the putative secreted protein against other staphylococci, including S. aureus strains USA100, USA300, three isolates of USA500, and S. epidermidis strains RP12 and RP62A were inoculated into biofilm media containing supernatant from strain Newman. The putative protein effectively inhibited biofilm formation by all S. aureus strains tested but did not inhibit biofilm formation by either S. epidermidis strain. Supernatant from Newman ΔsaePQRS::kan did not affect biofilm formation by any strain (Fig 5). The lack of an inhibitory effect on S. epidermidis could be due to species-dependent differences in biofilm formation. S. epidermidis relies more heavily on exopolysaccharides than exoproteins for biofilm formation. Some S. aureus strains on the other hand, rely primarily on exoproteins for biofilm formation, at least in the presence of plasma proteins [4,6]. Alternatively, the actual target of the inhibitor may not be expressed by S. epidermidis.


SaeRS-dependent inhibition of biofilm formation in Staphylococcus aureus Newman.

Cue D, Junecko JM, Lei MG, Blevins JS, Smeltzer MS, Lee CY - PLoS ONE (2015)

The biofilm inhibitory protein limits biofilm in S. aureus but not S. epidermidis strains.Culture supernatants from strain Newman or the ΔsaePQRS::kan mutant were added to biofilm medium and anti-biofilm activity was tested against the bacterial strains listed to the left of the figure. “Medium” indicates that sterile medium was added in place of culture supernatant.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390220&req=5

pone.0123027.g005: The biofilm inhibitory protein limits biofilm in S. aureus but not S. epidermidis strains.Culture supernatants from strain Newman or the ΔsaePQRS::kan mutant were added to biofilm medium and anti-biofilm activity was tested against the bacterial strains listed to the left of the figure. “Medium” indicates that sterile medium was added in place of culture supernatant.
Mentions: The results above indicate that a secreted protein produced by strain Newman inhibited biofilm formation by strain UAMS-1 when added to biofilm medium at the time of inoculation. To test anti-biofilm activity of the putative secreted protein against other staphylococci, including S. aureus strains USA100, USA300, three isolates of USA500, and S. epidermidis strains RP12 and RP62A were inoculated into biofilm media containing supernatant from strain Newman. The putative protein effectively inhibited biofilm formation by all S. aureus strains tested but did not inhibit biofilm formation by either S. epidermidis strain. Supernatant from Newman ΔsaePQRS::kan did not affect biofilm formation by any strain (Fig 5). The lack of an inhibitory effect on S. epidermidis could be due to species-dependent differences in biofilm formation. S. epidermidis relies more heavily on exopolysaccharides than exoproteins for biofilm formation. Some S. aureus strains on the other hand, rely primarily on exoproteins for biofilm formation, at least in the presence of plasma proteins [4,6]. Alternatively, the actual target of the inhibitor may not be expressed by S. epidermidis.

Bottom Line: The inhibitory protein was found to affect the attachment step in biofilm formation, but had no effect on preformed biofilms.Although a number of candidate proteins were identified, none were found to be the actual inhibitor.RNA-Seq results indicated that sae regulates many genes that may affect biofilm formation by Newman.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, United States of America.

ABSTRACT
The SaeRS two-component regulatory system of Staphylococcus aureus is known to affect the expression of many genes. The SaeS protein is the histidine kinase responsible for phosphorylation of the response regulator SaeR. In S. aureus Newman, the sae system is constitutively expressed due to a point mutation in saeS, relative to other S. aureus strains, which results in substitution of proline for leucine at amino acid 18. Strain Newman is unable to form a robust biofilm and we report here that the biofilm-deficient phenotype is due to the saeSP allele. Replacement of the Newman saeSP with saeSL, or deletion of saeRS, resulted in a biofilm-proficient phenotype. Newman culture supernatants were observed to inhibit biofilm formation by other S. aureus strains, but did not affect biofilm formation by S. epidermidis. Culture supernatants of Newman saeSL or Newman ΔsaeRS had no significant effect on biofilm formation. The inhibitory factor was inactivated by incubation with proteinase K, but survived heating, indicating that the inhibitory protein is heat-stable. The inhibitory protein was found to affect the attachment step in biofilm formation, but had no effect on preformed biofilms. Replacement of saeSL with saeSP in the biofilm-proficient S. aureus USA300 FPR3757 resulted in the loss of biofilm formation. Culture supernatants of USA300 FPR3757 saeSP, did not inhibit biofilm formation by other staphylococci, suggesting that the inhibitory factor is produced but not secreted in the mutant strain. A number of biochemical methods were utilized to isolate the inhibitory protein. Although a number of candidate proteins were identified, none were found to be the actual inhibitor. In an effort to reduce the number of potential inhibitory genes, RNA-Seq analyses were done with wild-type strain Newman and the saeSL and ΔsaeRS mutants. RNA-Seq results indicated that sae regulates many genes that may affect biofilm formation by Newman.

No MeSH data available.


Related in: MedlinePlus