This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rachid, S. Articles by Ziebuhr, W. Search for Related Content PubMed PubMed Citation Articles by Rachid, S. Articles by Ziebuhr, W.

Journal of Bacteriology, December 2000, p. 6824-6826, Vol. 182, No. 23
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

Alternative Transcription Factor ^B Is Involved in Regulation of Biofilm Expression in a Staphylococcus aureus Mucosal Isolate

Shwan Rachid,¹ Knut Ohlsen,¹ Ursula Wallner,¹ Jörg Hacker,¹ Michael Hecker,² and Wilma Ziebuhr^1,*

Institut für Molekulare Infektionsbiologie, D-97070 Würzburg,¹ and Institut für Mikrobiologie und Molekularbiologie, 15, D-17487 Greifswald,² Germany

Received 26 June 2000/Accepted 12 September 2000

	ABSTRACT

Top Abstract Text References

Osmotic stress was found to induce biofilm formation in a Staphylococcus aureus mucosal isolate. Inactivation of a global regulator of the bacterial stress response, the alternative transcription factor ^B, resulted in a biofilm-negative phenotype and loss of salt-induced biofilm production. Complementation of the mutant strain with an expression plasmid encoding ^B completely restored the wild-type phenotype. The combined data suggest a critical role of ^B in S. aureus biofilm regulation under environmental stress conditions.

	TEXT

Top Abstract Text References

For numerous pathogenic bacteria, biofilms represent a source of persisting and relapsing infections and thus contribute significantly to pathogenesis (4). Biofilms seem to protect bacteria from unfavorable external conditions, and, in some bacterial ecosystems, the conversion of planktonic cells into a biofilm-producing community is triggered by environmental stress factors (6, 12, 13). In the human pathogen Staphylococcus aureus, biofilm formation is mediated by the production of the extracellular polysaccharide adhesin PIA, whose synthesis depends on the expression of the icaADBC-encoded enzymes (5, 15). The regulation of biofilm expression in this organism is poorly understood. All S. aureus strains analyzed so far contain the entire ica gene cluster, but only a few express the operon and produce biofilms in vitro (5). In this study, we investigated whether the alternative transcription factor ^B is involved in the regulation of ica expression. ^B is known to be a global regulator of the stress response in S. aureus and also influences various virulence-associated genes (7, 11, 16, 20). To elucidate the possible role of ^B in biofilm formation, we used a genetic approach and constructed an S. aureus sigB::ermB insertion mutant of the biofilm-forming, methicillin-sensitive mucosal isolate S. aureus MA12 (18). Biofilm formation and ica expression of the mutant were compared with the phenotypes of the corresponding wild-type strain and a complemented strain that carried a sigB copy on an expression vector.

Construction of a sigB insertion mutant and complementation of the mutation. The inactivation of sigB was done by insertion of an erythromycin resistance cassette into the sigB gene of S. aureus MA12 by double-crossover integration. For this purpose, the temperature-sensitive shuttle vector pSK8, which carries a sigB::ermB mutation, was constructed. A 937-bp fragment containing the entire sigB gene was amplified by PCR from S. aureus MA12 by using the primers 5' CGG GAT CCG GTG TGA CAA TCA GTA TGA C 3' and 5' CGG AAT TCG CGA CAT TTA TGT GGA TAC AC 3'. The DNA fragment was inserted into the shuttle vector pBT1 (17), resulting in pSK7. Then the ermB cassette of pEC1 (1) was excised by XbaI-HindIII digestion, treated with the Klenow fragment of Escherichia coli DNA polymerase, and ligated with EcoRV-digested pSK7, resulting in plasmid pSK8. Following passage through the restriction-negative strain S. aureus RN4220, pSK8 was reisolated and transformed into S. aureus MA12 by electroporation (19). Replacement of the chromosomal S. aureus MA12 sigB wild-type gene was achieved by double-crossover integration of the sigB::ermB insert of pSK8 following a temperature shift to the nonpermissive temperature of the shuttle vector (42°C). Erythromycin-resistant and chloramphenicol-sensitive colonies were isolated, and the sigB::ermB integrations were confirmed by Southern hybridization, PCR, and nucleotide sequencing (data not shown). From these experiments, the sigB::ermB insertion mutant S. aureus MA12.2 was selected for further analysis. To restore the ^B function, the S. aureus MA12.2 sigB mutant strain was complemented with plasmid pSK9. Plasmid pSK9 was constructed by inserting the sigB PCR fragment into the expression shuttle vector pHPS9 (8). Prior to transformation into S. aureus MA12.2, the vector was transformed into the restriction-negative cloning host S. aureus RN4220. The plasmid was reisolated and transferred into S. aureus MA12.2, resulting in the complemented strain S. aureus MA12.2-1(pSK9).

Analysis of the ^B function. Inactivation of the sigB gene in S. aureus MA12.2 and restoration of its function in the complemented strain S. aureus MA12.2-1(pSK9) was investigated by Northern analysis of the asp23-specific gene expression. asp23 encodes an alkaline shock protein, and the gene was shown to be preceded by a ^B-dependent promoter (7, 11). Recent studies have shown that asp23 transcription is absent in S. aureus sigB mutants. It has therefore been concluded that asp23 transcription reliably reflects the activity of the ^B factor (7, 11, 16).

The Northern hybridization experiments revealed a strong asp23-specific signal in both the wild-type and the complemented strains. In contrast, no asp23-specific transcription was detected in the mutant strain S. aureus MA12.2 (data not shown). Furthermore, as expected for a ^B-negative strain (2, 11), and in contrast to both the wild-type and complemented strains, the mutant strain had lost its yellow pigmentation and showed enhanced hemolysis on blood agar plates (data not shown). Taken together, these data indicate that S. aureus MA12.2 is a sigB mutant and that the sigB mutation is restored in the complemented strain S. aureus MA12.2-1(pSK9).

Effect of the sigB mutation on biofilm production and ica expression. Quantitative biofilm measurement was done in a microtiter assay as described previously (3, 22). Bacteria were grown overnight in 96-well, flat-bottomed tissue culture plates (Greiner, Nürtingen, Germany) at 37°C using either tryptic soy broth (TSB) (Difco, BBL, Detroit, Mich.) or TSB supplemented with 3% sodium chloride as growth medium. Based upon the optical densities (OD) of the biofilms, the strains were classified as nonadherent strains (OD  0.120), weak biofilm producers (0.120 < OD  0.240), or strongly adherent strains (OD > 0.240) according to the scheme introduced by Christensen et al. (3). As shown in Fig. 1, the biofilm formation of S. aureus MA12 was weak when the strain was grown in TSB, but it could be significantly stimulated under osmotic stress conditions (that is, TSB containing 3% sodium chloride). In contrast, the S. aureus MA12.2 sigB insertion mutant failed to produce any detectable biofilm, irrespective of whether it was grown in TSB alone or in TSB containing 3% sodium chloride. In the case of S. aureus MA12.2(pSK9), in which the inactivated chromosomal copy of sigB was complemented by an expression plasmid carrying sigB, both basal and the osmotic stress-stimulated biofilm formation were restored.

View larger version (23K): [in this window] [in a new window]   FIG. 1.   Biofilm formation on polystyrene tissue culture plates of the wild-type strain (S. aureus MA12), the sigB::ermB insertion mutant (S. aureus MA12.2), the complemented strain [S. aureus MA12.2-1(pSK9)], the cloning host S. aureus RN4220, S. aureus RN4220(pSK9), and S. aureus RN4220(pCN27) carrying the icaADBC operon of S. epidermidis on plasmid pCN27 (9), and S. carnosus TM300(pCN27) (9) after growth in unsupplemented TSB and TSB supplemented with 3% sodium chloride, respectively. A, S. epidermidis RP62A (positive control); and B, S. carnosus TM300 (negative control).

Next, we examined the effect of the sigB inactivation on the transcription of the ica gene cluster by Northern blotting experiments. To this end, RNA was isolated from mid-log cultures of the wild-type strain, the sigB mutant, and the complemented strain, which were grown in TSB containing 3% sodium chloride. Hybridization with a ³²P-radiolabeled icaA-specific gene probe revealed a strong signal in the S. aureus MA12 wild-type strain (Fig. 2, lane 1). In contrast, ica transcription was drastically diminished in the sigB mutant (Fig. 2, lane 2) and restored in the complemented strain S. aureus MA12.2SK(pSK9) (Fig. 2, lane 3). These data are consistent with the observed differences in biofilm production under high-salt conditions between the wild-type and mutant strains and again support the conclusion that sigB is involved in the control of biofilm formation in S. aureus MA12.

View larger version (74K): [in this window] [in a new window]   FIG. 2.   Northern blot analysis of ica transcription in the S. aureus MA12 wild-type strain (lane 1), the sigB::ermB insertion mutant S. aureus MA12.2 (lane 2), and the complemented strain S. aureus MA12.2-1(pSK9) (lane 3) after growth in TSB supplemented with 3% sodium chloride.

We then extended the study to another S. aureus strain, RN4220. S. aureus RN4220 is a restriction-negative strain that is commonly used as a cloning host for plasmids prior to their transformation into the staphylococcal strain of interest (10). S. aureus RN4220 had been derived from S. aureus 8325, which was described recently as a spontaneous sigB-negative mutant with an 11-bp deletion in the rsbU regulatory gene (11, 20). Normally, S. aureus RN4220 does not produce biofilms, under either low-salt or high-salt conditions (Fig. 1). We found that, when transformed with plasmid pSK9, this strain formed biofilms and, moreover, that the biofilm production was induced under high-salt conditions. These results led us to propose that the biofilm-negative phenotype of S. aureus RN4220 is caused by the absence of ^B. Obviously, this conclusion appears to contradict previous results which demonstrated that S. aureus RN4220 exhibits a biofilm-positive phenotype when the icaADBC genes are provided on a plasmid (5, 14). Therefore, we have done an additional set of experiments. We have transformed plasmid pCN27 (9), which carries the entire ica operon of Staphylococcus epidermidis, into S. aureus RN4220. Consistent with previous data (14), the strain formed a biofilm when grown in TSB (Fig. 1). However, in obvious contrast to the pSK9 complementation experiments described above, no induction of biofilm production was observed under osmotic stress conditions. Finally, we found that propagation of pCN27 in Staphylococcus carnosus TM300 (9) increased the biofilm production of this strain under high-salt conditions. The combined data led us to hypothesize that the biofilm-forming phenotype of S. aureus RN4220(pCN27) may result from a basal, vector-driven ica expression, which is enhanced by the copy effect of the plasmid. The absence of biofilm induction, however, suggests that ^B is required for the activation of biofilm formation in response to osmotic stress.

Conclusions. In this study, we provide evidence that the biofilm-forming phenotype observed in a mucosal isolate of S. aureus can be induced by changing environmental conditions (in this case, osmotic stress). The results are consistent with our recent data obtained for S. epidermidis (S. Rachid and W. Ziebuhr, unpublished data), which demonstrated that the expression of the biofilm-mediating ica operon is enhanced by high osmolarity, high temperature, and subinhibitory concentrations of certain antibiotics. In contrast to S. epidermidis, all S. aureus strains analyzed so far carry the ica gene cluster, but only a few spontaneously express biofilms in vitro (5). It is thus tempting to speculate that, in these biofilm-negative strains, the ica expression may be tightly controlled. The data presented in this study strongly support the idea that this suppression might be overcome by activation of ^B in response to external stress. Another explanation for the biofilm-negative phenotype in the majority of the S. aureus strains would be the presence of mutations in the sigB gene itself or in its adjacent rsbU, rsbV, and rsbW regulatory genes (11, 20). It is also conceivable that S. aureus biofilm production may be influenced by mechanisms that have been shown to be used by S. epidermidis in the control of the ica expression (e.g., phase variation and gene rearrangements) (21-23). All these hypotheses still need careful experimental evaluation. It should also be noted that, in this study, we have characterized only the mucosal isolate S. aureus MA12 in detail. Even though we have obtained conclusive evidence for the critical involvement of the ^B factor in biofilm formation in this isolate, the actual role of ^B in ica expression remains to be determined. The nucleotide sequence immediately upstream of the ica operon does not resemble any of the known ^B-dependent promoter structures, suggesting an indirect activation of the ica expression by additional unknown regulatory factors. This idea is also supported by the identification of S. aureus strains which express the sigB gene but, nevertheless, are biofilm negative (Rachid and Ziebuhr, unpublished). To answer the question of whether ^B is directly or indirectly involved in S. aureus ica expression, more experimental work, including primer extension analyses under different growth conditions, is needed. Finally, a broad range of S. aureus strains has to be analyzed to identify possible variations in biofilm regulation among different strains.

	ACKNOWLEDGMENTS

This work was supported by the BMBF (grant no. 01KI9608), the Deutsche Forschungsgemeinschaft (Graduiertenkolleg Infektiologie), and the Fond der Chemischen Industrie.

We are grateful to Jürgen Kreft, Lehrstuhl für Mikrobiologie, Universität Würzburg, for providing plasmid pHSP9, and to Friedrich Götz, Mikrobielle Genetik, Universität Tübingen, for plasmid pCN27.

	FOOTNOTES

^* Corresponding author. Mailing address: Institut für Molekulare Infektionsbiologie, Röntgenring 11, D-97070 Würzburg, Germany. Phone: 49-931- 31 2154. Fax: 49-931- 31 2578. E-mail: w.ziebuhr{at}mail.uni-wuerzburg.de.

	REFERENCES

Top Abstract Text References

1.	Brückner, R. 1997. Gene replacement in Staphylococcus carnosus and Staphylococcus xylosus. FEMS Microbiol. Lett. 151:1-8[Medline].
2.	Cheung, A. L., Y.-T. Chien, and A. S. Bayer. 1999. Hyperproduction of alpha-hemolysin in a sigB mutant is associated with elevated SarA expression in Staphylococcus aureus. Infect. Immun. 67:1331-1337[Abstract/Free Full Text].
3.	Christensen, G. D., W. A. Simpson, J. J. Younger, L. M. Baddour, F. F. Barrett, D. M. Melton, and E. H. Beachey. 1985. Adherence of coagulase-negative staphylococci to plastic tissue culture plates: a quantitative model for the adherence of staphylococci to medical devices. J. Clin. Microbiol. 22:996-1006[Abstract/Free Full Text].
4.	Costerton, J. W., P. S. Stewart, and E. P. Greenberg. 1999. Bacterial biofilms: a common cause of persistent infections. Science 284:1318-1322[Abstract/Free Full Text].
5.	Cramton, S. E., C. Gerke, N. F. Schnell, W. W. Nichols, and F. Götz. 1999. The intercellular adhesion (ica) locus is present in Staphylococcus aureus and is required for biofilm formation. Infect. Immun. 67:5427-5433[Abstract/Free Full Text].
6.	Deretic, V., M. J. Schurr, J. C. Boucher, and D. W. Martin. 1994. Conversion of Pseudomonas aeruginosa to mucoidy in cystic fibrosis: environmental stress and regulation of bacterial virulence by alternative sigma factors. J. Bacteriol. 176:2773-2780[Free Full Text].
7.	Gertz, S., S. Engelmann, R. Schmid, K. Ohlsen, J. Hacker, and M. Hecker. 1999. Regulation of sigmaB-dependent transcription of sigB and asp23 in two different Staphylococcus aureus strains. Mol. Gen. Genet. 261:558-566[CrossRef][Medline].
8.	Haima, P., D. van Sinderen, S. Bron, and G. Venema. 1990. An improved beta-galactosidase alpha-complementation system for molecular cloning in Bacillus subtilis. Gene 93:41-47[CrossRef][Medline].
9.	Heilmann, C., O. Schweitzer, C. Gerke, N. Vanittanakom, D. Mack, and F. Götz. 1996. Molecular basis of intercellular adhesion in the biofilm-forming Staphylococcus epidermidis. Mol. Microbiol. 20:1083-1091[Medline].
10.	Kreiswirth, B. N., S. Lofdahl, M. J. Betley, M. O'Reilly, P. M. Schlievert, M. S. Bergdoll, and R. P. Novick. 1983. The toxic shock syndrome exotoxin structural gene is not detectably transmitted by a prophage. Nature 305:709-712[CrossRef][Medline].
11.	Kullik, I., P. Giachino, and T. Fuchs. 1998. Deletion of the alternative sigma factor B in Staphylococcus aureus reveals its function as a global regulator of virulence genes. J. Bacteriol. 180:4814-4820[Abstract/Free Full Text].
12.	LaPaglia, C., and P. L. Hartzell. 1997. Stress-induced production of biofilm in the hyperthermophile Archaeoglobus fulgidus. Appl. Environ. Microbiol. 63:3158-3163[Abstract].
13.	Mathee, K., O. Ciofu, C. Sternberg, P. W. Lindum, J. I. Campbell, P. Jensen, A. H. Johnsen, M. Givskov, D. E. Ohman, S. Molin, N. Hoiby, and A. Kharazmi. 1999. Mucoid conversion of Pseudomonas aeruginosa by hydrogen peroxide: a mechanism for virulence activation in the cystic fibrosis lung. Microbiology 145:1349-1357[Abstract].
14.	McKenney, D., J. Hübner, E. Muller, Y. Wang, D. A. Goldmann, and G. B. Pier. 1998. The ica locus of Staphylococcus epidermidis encodes production of the capsular polysaccharide/adhesin. Infect. Immun. 66:4711-4720[Abstract/Free Full Text].
15.	McKenney, D., K. L. Pouliot, Y. Wang, V. Murthy, M. Ulrich, G. Doring, J. C. Lee, D. A. Goldmann, and G. B. Pier. 1999. Broadly protective vaccine for Staphylococcus aureus based on an in vivo-expressed antigen. Science 284:1523-1527[Abstract/Free Full Text].
16.	Miyazaki, E., J.-M. Chen, C. Ko, and W. R. Bishai. 1999. The Staphylococcus aureus rsbW (orf159) gene encodes an anti-sigma factor of SigB. J. Bacteriol. 181:2846-2851[Abstract/Free Full Text].
17.	Ohlsen, K., K.-P. Koller, and J. Hacker. 1997. Analysis of expression of the alpha-toxin gene (hla) of Staphylococcus aureus by using a chromosomally encoded hla::lacZ gene fusion. Infect. Immun. 65:3606-3614[Abstract].
18.	Ohlsen, K., W. Ziebuhr, K.-P. Koller, W. Hell, T. A. Wichelhaus, and J. Hacker. 1998. Effects of subinhibitory concentrations of antibiotics on alpha-toxin (hla) gene expression of methicillin-sensitive and methicillin-resistant Staphylococcus aureus isolates. Antimicrob. Agents Chemother. 42:2817-2823[Abstract/Free Full Text].
19.	Schenk, S., and R. A. Laddaga. 1992. Improved method for electroporation of Staphylococcus aureus. FEMS Microbiol. Lett. 73:133-138[Medline].
20.	Wu, S., H. de Lencastre, and A. Tomasz. 1996. Sigma-B, a putative operon encoding alternate sigma factor of Staphylococcus aureus RNA polymerase: molecular cloning and DNA sequencing. J. Bacteriol. 178:6036-6042[Abstract/Free Full Text].
21.	Ziebuhr, W., K. Dietrich, M. Trautmann, and M. Wilhelm. 2000. Chromosomal rearrangements affecting biofilm production and antibiotic resistance in a S. epidermidis strain causing shunt-associated ventriculitis. Int. J. Med. Microbiol. 290:115-120[Medline].
22.	Ziebuhr, W., C. Heilmann, F. Götz, P. Meyer, K. Wilms, E. Straube, and J. Hacker. 1997. Detection of the intercellular adhesion gene cluster (ica) and phase variation in Staphylococcus epidermidis blood culture strains and mucosal isolates. Infect. Immun. 65:890-896[Abstract].
23.	Ziebuhr, W., V. Krimmer, S. Rachid, I. Lößner, F. Götz, and J. Hacker. 1999. A novel mechanism of phase variation of virulence in Staphylococcus epidermidis: evidence for control of the polysaccharide intercellular adhesin synthesis by alternating insertion and excision of the insertion sequence element IS256. Mol. Microbiol. 32:345-356[CrossRef][Medline].

---

Journal of Bacteriology, December 2000, p. 6824-6826, Vol. 182, No. 23
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

This article has been cited by other articles:

• Nagorska, K., Hinc, K., Strauch, M. A., Obuchowski, M. (2008). Influence of the {sigma}B Stress Factor and yxaB, the Gene for a Putative Exopolysaccharide Synthase under {sigma}B Control, on Biofilm Formation. J. Bacteriol. 190: 3546-3556 [Abstract] [Full Text]  
• Johnson, M., Cockayne, A., Morrissey, J. A. (2008). Iron-Regulated Biofilm Formation in Staphylococcus aureus Newman Requires ica and the Secreted Protein Emp. Infect. Immun. 76: 1756-1765 [Abstract] [Full Text]  
• Schlag, S., Nerz, C., Birkenstock, T. A., Altenberend, F., Gotz, F. (2007). Inhibition of Staphylococcal Biofilm Formation by Nitrite. J. Bacteriol. 189: 7911-7919 [Abstract] [Full Text]  
• Zhu, Y., Weiss, E. C., Otto, M., Fey, P. D., Smeltzer, M. S., Somerville, G. A. (2007). Staphylococcus aureus Biofilm Metabolism and the Influence of Arginine on Polysaccharide Intercellular Adhesin Synthesis, Biofilm Formation, and Pathogenesis. Infect. Immun. 75: 4219-4226 [Abstract] [Full Text]  
• Zhang, X.-S., Garcia-Contreras, R., Wood, T. K. (2007). YcfR (BhsA) Influences Escherichia coli Biofilm Formation through Stress Response and Surface Hydrophobicity. J. Bacteriol. 189: 3051-3062 [Abstract] [Full Text]  
• Valle, J., Vergara-Irigaray, M., Merino, N., Penades, J. R., Lasa, I. (2007). {sigma}B Regulates IS256-Mediated Staphylococcus aureus Biofilm Phenotypic Variation. J. Bacteriol. 189: 2886-2896 [Abstract] [Full Text]  
• Tu Quoc, P. H., Genevaux, P., Pajunen, M., Savilahti, H., Georgopoulos, C., Schrenzel, J., Kelley, W. L. (2007). Isolation and Characterization of Biofilm Formation-Defective Mutants of Staphylococcus aureus. Infect. Immun. 75: 1079-1088 [Abstract] [Full Text]  
• Goldstein, F. (2007). The potential clinical impact of low-level antibiotic resistance in Staphylococcus aureus. J Antimicrob Chemother 59: 1-4 [Abstract] [Full Text]  
• Shanks, R. M. Q., Sargent, J. L., Martinez, R. M., Graber, M. L., O'Toole, G. A. (2006). Catheter lock solutions influence staphylococcal biofilm formation on abiotic surfaces. Nephrol Dial Transplant 21: 2247-2255 [Abstract] [Full Text]  
• Alvarez, B., Secades, P., Prieto, M., McBride, M. J., Guijarro, J. A. (2006). A Mutation in Flavobacterium psychrophilum tlpB Inhibits Gliding Motility and Induces Biofilm Formation.. Appl. Environ. Microbiol. 72: 4044-4053 [Abstract] [Full Text]  
• Mathew, R., Mukherjee, R., Balachandar, R., Chatterji, D. (2006). Deletion of the rpoZ gene, encoding the {omega} subunit of RNA polymerase, results in pleiotropic surface-related phenotypes in Mycobacterium smegmatis. Microbiology 152: 1741-1750 [Abstract] [Full Text]  
• Viswanathan, P., Singer, M., Kroos, L. (2006). Role of {sigma}D in Regulating Genes and Signals during Myxococcus xanthus Development. J. Bacteriol. 188: 3246-3256 [Abstract] [Full Text]  
• Kazmierczak, M. J., Wiedmann, M., Boor, K. J. (2005). Alternative Sigma Factors and Their Roles in Bacterial Virulence. Microbiol. Mol. Biol. Rev. 69: 527-543 [Abstract] [Full Text]  
• Senn, M. M., Giachino, P., Homerova, D., Steinhuber, A., Strassner, J., Kormanec, J., Fluckiger, U., Berger-Bachi, B., Bischoff, M. (2005). Molecular Analysis and Organization of the {sigma}B Operon in Staphylococcus aureus. J. Bacteriol. 187: 8006-8019 [Abstract] [Full Text]  
• Johnson, M., Cockayne, A., Williams, P. H., Morrissey, J. A. (2005). Iron-Responsive Regulation of Biofilm Formation in Staphylococcus aureus Involves Fur-Dependent and Fur-Independent Mechanisms. J. Bacteriol. 187: 8211-8215 [Abstract] [Full Text]  
• Trotonda, M. P., Manna, A. C., Cheung, A. L., Lasa, I., Penades, J. R. (2005). SarA Positively Controls Bap-Dependent Biofilm Formation in Staphylococcus aureus. J. Bacteriol. 187: 5790-5798 [Abstract] [Full Text]  
• Shanks, R. M. Q., Donegan, N. P., Graber, M. L., Buckingham, S. E., Zegans, M. E., Cheung, A. L., O'Toole, G. A. (2005). Heparin Stimulates Staphylococcus aureus Biofilm Formation. Infect. Immun. 73: 4596-4606 [Abstract] [Full Text]  
• Toledo-Arana, A., Merino, N., Vergara-Irigaray, M., Debarbouille, M., Penades, J. R., Lasa, I. (2005). Staphylococcus aureus Develops an Alternative, ica-Independent Biofilm in the Absence of the arlRS Two-Component System. J. Bacteriol. 187: 5318-5329 [Abstract] [Full Text]  
• Vuong, C., Kidder, J. B., Jacobson, E. R., Otto, M., Proctor, R. A., Somerville, G. A. (2005). Staphylococcus epidermidis Polysaccharide Intercellular Adhesin Production Significantly Increases during Tricarboxylic Acid Cycle Stress. J. Bacteriol. 187: 2967-2973 [Abstract] [Full Text]  
• Zhang, H., Morikawa, K., Ohta, T., Kato, Y. (2005). In vitro resistance to the CS{alpha}{beta}-type antimicrobial peptide ASABF- is conferred by overexpression of sigma factor sigB in Staphylococcus aureus. J Antimicrob Chemother 55: 686-691 [Abstract] [Full Text]  
• Streker, K., Freiberg, C., Labischinski, H., Hacker, J., Ohlsen, K. (2005). Staphylococcus aureus NfrA (SA0367) Is a Flavin Mononucleotide-Dependent NADPH Oxidase Involved in Oxidative Stress Response. J. Bacteriol. 187: 2249-2256 [Abstract] [Full Text]  
• Tormo, M. A., Marti, M., Valle, J., Manna, A. C., Cheung, A. L., Lasa, I., Penades, J. R. (2005). SarA Is an Essential Positive Regulator of Staphylococcus epidermidis Biofilm Development. J. Bacteriol. 187: 2348-2356 [Abstract] [Full Text]  
• Knobloch, J. K.-M., Jager, S., Huck, J., Horstkotte, M. A., Mack, D. (2005). mecA Is Not Involved in the {sigma}B-Dependent Switch of the Expression Phenotype of Methicillin Resistance in Staphylococcus epidermidis. Antimicrob. Agents Chemother. 49: 1216-1219 [Abstract] [Full Text]  
• Fluckiger, U., Ulrich, M., Steinhuber, A., Doring, G., Mack, D., Landmann, R., Goerke, C., Wolz, C. (2005). Biofilm Formation, icaADBC Transcription, and Polysaccharide Intercellular Adhesin Synthesis by Staphylococci in a Device-Related Infection Model. Infect. Immun. 73: 1811-1819 [Abstract] [Full Text]  
• Kennedy, C. A, O'Gara, J. P (2004). Contribution of culture media and chemical properties of polystyrene tissue culture plates to biofilm development by Staphylococcus aureus. J Med Microbiol 53: 1171-1173 [Full Text]  
• Jonsson, I.-M., Arvidson, S., Foster, S., Tarkowski, A. (2004). Sigma Factor B and RsbU Are Required for Virulence in Staphylococcus aureus-Induced Arthritis and Sepsis. Infect. Immun. 72: 6106-6111 [Abstract] [Full Text]  
• Conlon, K. M., Humphreys, H., O'Gara, J. P. (2004). Inactivations of rsbU and sarA by IS256 Represent Novel Mechanisms of Biofilm Phenotypic Variation in Staphylococcus epidermidis. J. Bacteriol. 186: 6208-6219 [Abstract] [Full Text]  
• Beenken, K. E., Dunman, P. M., McAleese, F., Macapagal, D., Murphy, E., Projan, S. J., Blevins, J. S., Smeltzer, M. S. (2004). Global Gene Expression in Staphylococcus aureus Biofilms. J. Bacteriol. 186: 4665-4684 [Abstract] [Full Text]  
• Knobloch, J. K.-M., Jager, S., Horstkotte, M. A., Rohde, H., Mack, D. (2004). RsbU-Dependent Regulation of Staphylococcus epidermidis Biofilm Formation Is Mediated via the Alternative Sigma Factor {sigma}B by Repression of the Negative Regulator Gene icaR. Infect. Immun. 72: 3838-3848 [Abstract] [Full Text]  
• Bischoff, M., Dunman, P., Kormanec, J., Macapagal, D., Murphy, E., Mounts, W., Berger-Bachi, B., Projan, S. (2004). Microarray-Based Analysis of the Staphylococcus aureus {sigma}B Regulon. J. Bacteriol. 186: 4085-4099 [Abstract] [Full Text]  
• Jefferson, K. K., Pier, D. B., Goldmann, D. A., Pier, G. B. (2004). The Teicoplanin-Associated Locus Regulator (TcaR) and the Intercellular Adhesin Locus Regulator (IcaR) Are Transcriptional Inhibitors of the ica Locus in Staphylococcus aureus. J. Bacteriol. 186: 2449-2456 [Abstract] [Full Text]  
• Lim, Y., Jana, M., Luong, T. T., Lee, C. Y. (2004). Control of Glucose- and NaCl-Induced Biofilm Formation by rbf in Staphylococcus aureus. J. Bacteriol. 186: 722-729 [Abstract] [Full Text]  
• Uziel, O., Borovok, I., Schreiber, R., Cohen, G., Aharonowitz, Y. (2004). Transcriptional Regulation of the Staphylococcus aureus Thioredoxin and Thioredoxin Reductase Genes in Response to Oxygen and Disulfide Stress. J. Bacteriol. 186: 326-334 [Abstract] [Full Text]  
• Kristich, C. J., Li, Y.-H., Cvitkovitch, D. G., Dunny, G. M. (2004). Esp-Independent Biofilm Formation by Enterococcus faecalis. J. Bacteriol. 186: 154-163 [Abstract] [Full Text]  
• Wu, J. A., Kusuma, C., Mond, J. J., Kokai-Kun, J. F. (2003). Lysostaphin Disrupts Staphylococcus aureus and Staphylococcus epidermidis Biofilms on Artificial Surfaces. Antimicrob. Agents Chemother. 47: 3407-3414 [Abstract] [Full Text]  
• Knobloch, J. K.-M., Nedelmann, M., Kiel, K., Bartscht, K., Horstkotte, M. A., Dobinsky, S., Rohde, H., Mack, D. (2003). Establishment of an Arbitrary PCR for Rapid Identification of Tn917 Insertion Sites in Staphylococcus epidermidis: Characterization of Biofilm-Negative and Nonmucoid Mutants. Appl. Environ. Microbiol. 69: 5812-5818 [Abstract] [Full Text]  
• Kazmierczak, M. J., Mithoe, S. C., Boor, K. J., Wiedmann, M. (2003). Listeria monocytogenes {sigma}B Regulates Stress Response and Virulence Functions. J. Bacteriol. 185: 5722-5734 [Abstract] [Full Text]  
• Moretro, T., Hermansen, L., Holck, A. L., Sidhu, M. S., Rudi, K., Langsrud, S. (2003). Biofilm Formation and the Presence of the Intercellular Adhesion Locus ica among Staphylococci from Food and Food Processing Environments. Appl. Environ. Microbiol. 69: 5648-5655 [Abstract] [Full Text]  
• Beenken, K. E., Blevins, J. S., Smeltzer, M. S. (2003). Mutation of sarA in Staphylococcus aureus Limits Biofilm Formation. Infect. Immun. 71: 4206-4211 [Abstract] [Full Text]  
• Dobinsky, S., Kiel, K., Rohde, H., Bartscht, K., Knobloch, J. K.-M., Horstkotte, M. A., Mack, D. (2003). Glucose-Related Dissociation between icaADBC Transcription and Biofilm Expression by Staphylococcus epidermidis: Evidence for an Additional Factor Required for Polysaccharide Intercellular Adhesin Synthesis. J. Bacteriol. 185: 2879-2886 [Abstract] [Full Text]  
• Sifri, C. D., Begun, J., Ausubel, F. M., Calderwood, S. B. (2003). Caenorhabditis elegans as a Model Host for Staphylococcus aureus Pathogenesis. Infect. Immun. 71: 2208-2217 [Abstract] [Full Text]  
• Price, C. T. D., Singh, V. K., Jayaswal, R. K., Wilkinson, B. J., Gustafson, J. E. (2002). Pine Oil Cleaner-Resistant Staphylococcus aureus: Reduced Susceptibility to Vancomycin and Oxacillin and Involvement of SigB. Appl. Environ. Microbiol. 68: 5417-5421 [Abstract] [Full Text]  
• Horsburgh, M. J., Aish, J. L., White, I. J., Shaw, L., Lithgow, J. K., Foster, S. J. (2002). {sigma}B Modulates Virulence Determinant Expression and Stress Resistance: Characterization of a Functional rsbU Strain Derived from Staphylococcus aureus 8325-4. J. Bacteriol. 184: 5457-5467 [Abstract] [Full Text]  
• Oosthuizen, M. C., Steyn, B., Theron, J., Cosette, P., Lindsay, D., von Holy, A., Brozel, V. S. (2002). Proteomic Analysis Reveals Differential Protein Expression by Bacillus cereus during Biofilm Formation. Appl. Environ. Microbiol. 68: 2770-2780 [Abstract] [Full Text]  
• Sakoulas, G., Eliopoulos, G. M., Moellering, R. C. Jr., Wennersten, C., Venkataraman, L., Novick, R. P., Gold, H. S. (2002). Accessory Gene Regulator (agr) Locus in Geographically Diverse Staphylococcus aureus Isolates with Reduced Susceptibility to Vancomycin. Antimicrob. Agents Chemother. 46: 1492-1502 [Abstract] [Full Text]  
• Bateman, B. T., Donegan, N. P., Jarry, T. M., Palma, M., Cheung, A. L. (2001). Evaluation of a Tetracycline-Inducible Promoter in Staphylococcus aureus In Vitro and In Vivo and Its Application in Demonstrating the Role of sigB in Microcolony Formation. Infect. Immun. 69: 7851-7857 [Abstract] [Full Text]  
• Palma, M., Cheung, A. L. (2001). sigma B Activity in Staphylococcus aureus Is Controlled by RsbU and an Additional Factor(s) during Bacterial Growth. Infect. Immun. 69: 7858-7865 [Abstract] [Full Text]  
• Kies, S., Otto, M., Vuong, C., Gotz, F. (2001). Identification of the sigB Operon in Staphylococcus epidermidis: Construction and Characterization of a sigB Deletion Mutant. Infect. Immun. 69: 7933-7936 [Abstract] [Full Text]  
• Rohde, H., Knobloch, J. K. M., Horstkotte, M. A., Mack ;, D., Arciola, C. R., Montanaro, L., Baldassarri, L. (2001). Correlation of Staphylococcus aureus icaADBC Genotype and Biofilm Expression Phenotype. J. Clin. Microbiol. 39: 4595-4596 [Full Text]  
• Knobloch, J. K.-M., Bartscht, K., Sabottke, A., Rohde, H., Feucht, H.-H., Mack, D. (2001). Biofilm Formation by Staphylococcus epidermidis Depends on Functional RsbU, an Activator of the sigB Operon: Differential Activation Mechanisms Due to Ethanol and Salt Stress. J. Bacteriol. 183: 2624-2633 [Abstract] [Full Text]  

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rachid, S. Articles by Ziebuhr, W. Search for Related Content PubMed PubMed Citation Articles by Rachid, S. Articles by Ziebuhr, W.