σBand SarA independently regulate polysaccharide intercellular adhesin production inStaphylococcus epidermidis

2007 ◽  
Vol 53 (1) ◽  
pp. 82-91 ◽  
Author(s):  
L D Handke ◽  
S R Slater ◽  
K M Conlon ◽  
Sinead T O'Donnell ◽  
M E Olson ◽  
...  
Keyword(s):  
Foreign Body ◽  
Staphylococcus Epidermidis ◽  
Promoter Region ◽  
Promoter Activity ◽  
Double Mutant ◽  
Direct Interaction ◽  
Transcriptional Analysis ◽  
Polysaccharide Intercellular Adhesin ◽  
Promoter Fusion ◽  
Biofilm Development

The production of polysaccharide intercellular adhesin (PIA) is an essential process in foreign body infections mediated by Staphylococcus epidermidis. Transcriptional regulation of the icaADBC operon, the genes responsible for production of enzymes that synthesize PIA, is multi-factorial and involves at least SarA and σB. Transcriptional and promoter fusion studies revealed that the decreased transcription of the icaADBC operon observed in a S. epidermidis 1457 sigB mutant is not mediated through a direct interaction of σB–RNA polymerase at the icaADBC promoter region but instead through the upregulation of IcaR, a known repressor of icaADBC transcription. Transcriptional analysis of a 1457 sigB–icaR double mutant confirmed that the decreased icaADBC transcript in 1457 sigB is IcaR dependent. Furthermore, primer extension studies suggest that the icaR promoter appears to be σAdependent, suggesting that σBindirectly controls icaR transcription through an unknown pathway. In addition, it was confirmed that the loss of SarA results in the loss of icaADBC transcription and PIA production in S. epidermidis. It was further demonstrated, through the over-production of SarA in 1457 sigB, that the loss of sarP1 promoter activity in 1457 sigB has little or no effect on the loss of PIA production in this mutant. Finally, it was demonstrated that PIA production could be restored in both 1457 sigB and 1457 sarA by complementing these mutants with a full-length icaADBC operon controlled by a cadmium-inducible noncognate promoter. It is concluded that σBand SarA operate independently of each other to regulate PIA production and biofilm development in S. epidermidis.Key words: Staphylococcus epidermidis, biofilm, σB, SarA, icaADBC.

Transcriptional activity of icaADBC is not correlated to the degree of biofilm formation in clinical ica-positive Staphylococcus epidermidis strains

Biofilms ◽  
2004 ◽  
Vol 1 (2) ◽  
pp. 101-106 ◽  
Author(s):  
S. Dobinsky ◽  
H. Rohde ◽  
J. K.-M. Knobloch ◽  
M. A. Horstkotte ◽  
D. Mack
Keyword(s):  
Sequence Analysis ◽  
Growth Phase ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Promoter Region ◽  
Transcriptional Activity ◽  
Exponential Growth Phase ◽  
Polysaccharide Intercellular Adhesin ◽  
Different Strains ◽  
Negative Phenotype

Biofilm-formation in Staphylococcus epidermidis depends on the expression of the icaADBC operon encoding the enzymes required for the synthesis of polysaccharide intercellular adhesin (PIA). Different S. epidermidis strains vary widely in the degree of PIA and biofilm that they produce. In 11 clinical S. epidermidis strains we analyzed the biofilm-forming capacity in relation to the amount of ica expressed in static biofilm cultures. In mid-exponential growth phase no correlation could be detected between the level of ica transcription and the biofilm-forming phenotype. When the different strains were grown under conditions leading to a biofilm-negative phenotype, ica-expression was highly upregulated. Sequence analysis demonstrated that the observed differences were not due to major mutations in the ica promoter region but apparently to other strain-specific regulators.

scholarly journals Oxygen-Mediated Regulation of Biofilm Development Is Controlled by the Alternative Sigma Factor σB in Staphylococcus epidermidis

2008 ◽  
Vol 75 (1) ◽  
pp. 261-264 ◽  
Author(s):  
John J. Cotter ◽  
James P. O'Gara ◽  
Dietrich Mack ◽  
Eoin Casey
Keyword(s):  
Staphylococcus Epidermidis ◽  
Sigma Factor ◽  
Rotating Disk ◽  
Negative Regulator ◽  
Alternative Sigma Factor ◽  
Polysaccharide Intercellular Adhesin ◽  
Anaerobic Conditions ◽  
Rotating Disk Reactor ◽  
Biofilm Development

ABSTRACT Using a modified rotating-disk reactor to sparge oxygen to Staphylococcus epidermidis cultures, we found that oxygen negatively regulates biofilm development by influencing the activity of σB. Under anaerobic conditions, increased σB activity activates icaADBC, which encodes enzymes responsible for polysaccharide intercellular adhesin synthesis, by repressing transcription of the negative regulator icaR.

scholarly journals Characterization of the Importance of Polysaccharide Intercellular Adhesin/Hemagglutinin of Staphylococcus epidermidis in the Pathogenesis of Biomaterial-Based Infection in a Mouse Foreign Body Infection Model

1999 ◽  
Vol 67 (5) ◽  
pp. 2627-2632 ◽  
Author(s):  
Mark E. Rupp ◽  
Joseph S. Ulphani ◽  
Paul D. Fey ◽  
Katrin Bartscht ◽  
Dietrich Mack
Keyword(s):  
Foreign Body ◽  
Staphylococcus Epidermidis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Infection Model ◽  
Polysaccharide Intercellular Adhesin ◽  
Wild Type ◽  
Bacterial Strains ◽  
Biofilm Production ◽  
Negative Mutant

ABSTRACT The production of biofilm is thought to be crucial in the pathogenesis of prosthetic-device infections caused byStaphylococcus epidermidis. An experimental animal model was used to assess the importance of biofilm production, which is mediated by polysaccharide intercellular adhesin/hemagglutinin (PIA/HA), in the pathogenesis of a biomaterial-based infection. Mice were inoculated along the length of a subcutaneously implanted intravenous catheter with either wild-type S. epidermidis1457 or its isogenic PIA/HA-negative mutant. The wild-type strain was significantly more likely to cause a subcutaneous abscess than the mutant strain (P < 0.01) and was significantly less likely to be eradicated from the inoculation site by host defense (P < 0.05). In addition, the wild-type strain was found to adhere to the implanted catheters more abundantly than the PIA/HA-negative mutant (P < 0.05). The reliability of the adherence assay was assessed by scanning electron microscopy. To exclude contamination or spontaneous infection, bacterial strains recovered from the experimental animals were compared to inoculation strains by analysis of restriction fragment length polymorphism patterns by pulsed-field gel electrophoresis. In vitro binding of the wild-type strain and its isogenic mutant to a fibronectin-coated surface was similar. These results confirm the importance of biofilm production, mediated by PIA/HA, in the pathogenesis of S. epidermidis experimental foreign body infection.

scholarly journals Inhibition of Staphylococcal Biofilm Formation by Nitrite

2007 ◽  
Vol 189 (21) ◽  
pp. 7911-7919 ◽  
Author(s):  
Steffen Schlag ◽  
Christiane Nerz ◽  
Timo A. Birkenstock ◽  
Florian Altenberend ◽  
Friedrich Götz
Keyword(s):  
Staphylococcus Epidermidis ◽  
Adaptive Response ◽  
Biofilm Formation ◽  
Iron Homeostasis ◽  
Nitrosative Stress ◽  
Transcriptional Analysis ◽  
Polysaccharide Intercellular Adhesin ◽  
Human Pathogens ◽  
Oxidative And Nitrosative Stress ◽  
Induced Stress

ABSTRACT Several environmental stresses have been demonstrated to increase polysaccharide intercellular adhesin (PIA) synthesis and biofilm formation by the human pathogens Staphylococcus aureus and Staphylococcus epidermidis. In this study we characterized an adaptive response of S. aureus SA113 to nitrite-induced stress and show that it involves concomitant impairment of PIA synthesis and biofilm formation. Transcriptional analysis provided evidence that nitrite, either as the endogenous product of respiratory nitrate reduction or after external addition, causes repression of the icaADBC gene cluster, mediated likely by IcaR. Comparative microarray analysis revealed a global change in gene expression during growth in the presence of 5 mM sodium nitrite and indicated a response to oxidative and nitrosative stress. Many nitrite-induced genes are involved in DNA repair, detoxification of reactive oxygen and nitrogen species, and iron homeostasis. Moreover, preformed biofilms could be eradicated by the addition of nitrite, likely the result of the formation of toxic acidified nitrite derivatives. Nitrite-mediated inhibition of S. aureus biofilm formation was abrogated by the addition of nitric oxide (NO) scavengers, suggesting that NO is directly or indirectly involved. Nitrite also repressed biofilm formation of S. epidermidis RP62A.

scholarly journals γ-Butyrolactone-Dependent Expression of the Streptomyces Antibiotic Regulatory Protein Gene srrY Plays a Central Role in the Regulatory Cascade Leading to Lankacidin and Lankamycin Production in Streptomyces rochei

2007 ◽  
Vol 190 (4) ◽  
pp. 1308-1316 ◽  
Author(s):  
Shouji Yamamoto ◽  
Yuxi He ◽  
Kenji Arakawa ◽  
Haruyasu Kinashi
Keyword(s):  
Signaling Pathway ◽  
Promoter Region ◽  
Double Mutant ◽  
Protein Gene ◽  
Antibiotic Production ◽  
Regulatory Protein ◽  
Transcriptional Analysis ◽  
Dependent Manner ◽  
Receptor System ◽  
Regulatory Cascade

ABSTRACT Our previous studies revealed that the srrX and srrA genes carried on the large linear plasmid pSLA2-L constitute a γ-butyrolactone-receptor system in Streptomyces rochei. Extensive transcriptional analysis has now showed that the Streptomyces antibiotic regulatory protein gene srrY, which is also carried on pSLA2-L, is a target of the receptor/repressor SrrA and plays a central role in lankacidin and lankamycin production. The srrY gene was expressed in a growth-dependent manner, slightly preceding antibiotic production. The expression of srrY was undetectable in the srrX mutant but was restored in the srrX srrA double mutant. In addition, SrrA was bound specifically to the promoter region of srrY, and this binding was prevented by the addition of the S. rochei γ-butyrolactone fraction, while the W119A mutant receptor SrrA was kept bound even in the presence of S. rochei γ-butyrolactone. Furthermore, the introduction of an intact srrY gene under the control of a foreign promoter into the srrX or srrA(W119A) mutant restored antibiotic production. All of these results confirmed the signaling pathway from srrX through srrA to srrY, leading to lankacidin and lankamycin production.

scholarly journals Formation and properties of in vitro biofilms of ica-negative Staphylococcus epidermidis clinical isolates

2007 ◽  
Vol 56 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Zhiqiang Qin ◽  
Xiaomei Yang ◽  
Lei Yang ◽  
Juan Jiang ◽  
Yuanzhu Ou ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Epidemiological Data ◽  
Clinical Isolates ◽  
Polysaccharide Intercellular Adhesin ◽  
Flow Conditions ◽  
Initial Attachment ◽  
Clinical Strains ◽  
Biofilm Development

Coagulase-negative Staphylococcus epidermidis has become the leading cause of foreign-body infections due to its biofilm formation on all kinds of medical-device surfaces. The biofilm development of S. epidermidis includes two steps: the initial attachment phase and the accumulative phase. In the accumulative phase, the polysaccharide intercellular adhesin (PIA), encoded by the icaADBC locus, is the major component mediating intercellular adhesion. However, recent studies have revealed the emergence of biofilm-positive/ica-negative staphylococcal clinical isolates. In this report, two ica-negative S. epidermidis clinical strains, SE1 and SE4, exhibited their heterogeneity in biofilm architecture under static and flow conditions, compared with the biofilm-positive/ica-positive RP62A strain. Strains with this type of absence of PIA from biofilms also displayed intermediate resistance to vancomycin. More importantly, the cells of both SE1 and SE4 strains were more tolerant than those of RP62A to exposure to lysostaphin and vancomycin. Based on the results, it is suggested that the biofilm-positive/ica-negative strain represents a newly emergent subpopulation of S. epidermidis clinical strains, arising from selection by antibiotics in the nosocomial milieu, which displays a survival advantage in its host environment. Recent epidemiological data support this suggestion, by showing a tendency towards an increasing proportion of this subpopulation in staphylococci-associated infections.

scholarly journals Regulation of Swarming Motility and flhDCSm Expression by RssAB Signaling in Serratia marcescens

2008 ◽  
Vol 190 (7) ◽  
pp. 2496-2504 ◽  
Author(s):  
Po-Chi Soo ◽  
Yu-Tze Horng ◽  
Jun-Rong Wei ◽  
Jwu-Ching Shu ◽  
Chia-Chen Lu ◽  
...  
Keyword(s):  
Serratia Marcescens ◽  
Binding Site ◽  
Promoter Region ◽  
Transcriptional Start Site ◽  
Direct Interaction ◽  
Underlying Mechanism ◽  
Inhibitory Effect ◽  
Start Codon ◽  
Mobility Shift

ABSTRACT Serratia marcescens cells swarm at 30°C but not at 37°C, and the underlying mechanism is not characterized. Our previous studies had shown that a temperature upshift from 30 to 37°C reduced the expression levels of flhDCSm and hagSm in S. marcescens CH-1. Mutation in rssA or rssB, cognate genes that comprise a two-component system, also resulted in precocious swarming phenotypes at 37°C. To further characterize the underlying mechanism, in the present study, we report that expression of flhDCSm and synthesis of flagella are significantly increased in the rssA mutant strain at 37°C. Primer extension analysis for determination of the transcriptional start site(s) of flhDCSm revealed two transcriptional start sites, P1 and P2, in S. marcescens CH-1. Characterization of the phosphorylated RssB (RssB∼P) binding site by an electrophoretic mobility shift assay showed direct interaction of RssB∼P, but not unphosphorylated RssB [RssB(D51E)], with the P2 promoter region. A DNase I footprinting assay using a capillary electrophoresis approach further determined that the RssB∼P binding site is located between base pair positions −341 and −364 from the translation start codon ATG in the flhDCSm promoter region. The binding site overlaps with the P2 “−35” promoter region. A modified chromatin immunoprecipitation assay was subsequently performed to confirm that RssB∼P binds to the flhDCSm promoter region in vivo. In conclusion, our results indicated that activated RssA-RssB signaling directly inhibits flhDCSm promoter activity at 37°C. This inhibitory effect was comparatively alleviated at 30°C. This finding might explain, at least in part, the phenomenon of inhibition of S. marcescens swarming at 37°C.

The transcription factor E2F-1 mediates the autoregulation of RB gene expression

1994 ◽  
Vol 14 (1) ◽  
pp. 299-309
Author(s):  
B Shan ◽  
C Y Chang ◽  
D Jones ◽  
W H Lee
Keyword(s):  
Promoter Region ◽  
Promoter Activity ◽  
Cell Cycle Progression ◽  
Gene Mutations ◽  
Suppressor Gene ◽  
Recognition Sequence ◽  
Cycle Progression ◽  
Rb Gene ◽  
Transcription Factor E2f ◽  
Stimulation Of

The retinoblastoma (RB) gene is the prototype tumor suppressor gene. Mutations in this gene are often associated with the occurrence of various tumors. Several mutations have been found in the promoter region of the gene, suggesting that inappropriate transcriptional regulation of the RB gene contributes to tumorigenesis. Sequence analysis of the RB promoter has revealed a potential E2F recognition site within a region critical for RB gene transcription. By using the cloned E2F-1 gene, here we report that (i) RB expression is negatively regulated by its own gene product, (ii) E2F-1 binds specifically to an E2F recognition sequence in the RB promoter and transactivates the RB promoter, (iii) overexpression of RB suppresses E2F-1-mediated stimulation of RB promoter activity, and (iv) the expression of the RB gene is paralleled by the expression of the E2F-1 gene during cell cycle progression. These results demonstrate that expression of RB is negatively autoregulated through E2F-1.

Identification of functional TTF-1 and Sp1/Sp3 sites in the upstream promoter region of rabbit SP-B gene

2000 ◽  
Vol 278 (3) ◽  
pp. L477-L484 ◽  
Author(s):  
Ramgopal Margana ◽  
Kiflu Berhane ◽  
M. Nurul Alam ◽  
Vijayakumar Boggaram
Keyword(s):  
Promoter Region ◽  
Promoter Activity ◽  
Mutational Analysis ◽  
Surfactant Protein ◽  
Alveolar Type ◽  
Deletion Mapping ◽  
Clara Cells ◽  
Mobility Shift ◽  
Upstream Promoter ◽  
Upstream Promoter Region

Surfactant protein B (SP-B) is essential for the maintenance of biophysical properties and physiological function of pulmonary surfactant. SP-B mRNA is expressed in a cell type-restricted manner in alveolar type II and bronchiolar (Clara) epithelial cells of the lung and is developmentally induced. In NCI-H441 cells, a lung cell line with characteristics of Clara cells, a minimal promoter region comprising −236 to +39 nucleotides supports high-level expression of chloramphenicol acetyltransferase reporter activity. In the present investigation, we characterized the upstream promoter region, −236 to −140 nucleotides, that is essential for promoter activity. Deletion mapping identified two segments, −236 to −170 and −170 to −140 nucleotides, that are important for promoter activity. Mutational analysis and gel mobility shift experiments identified thyroid transcription factor-1, Sp1, and Sp3 as important trans-acting factors that bind to sequences in the upstream promoter region. Our data suggest that SP-B promoter activity is dependent on interactions between factors bound to upstream and downstream regions of the promoter.

Investigation of the roles of AgrA and σB regulators in Listeria monocytogenes adaptation to roots and soil

2020 ◽  
Vol 367 (3) ◽  
Author(s):  
Catarina M Marinho ◽  
Dominique Garmyn ◽  
Laurent Gal ◽  
Maja Z Brunhede ◽  
Conor O'Byrne ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Parental Strain ◽  
Festuca Arundinacea ◽  
Double Mutant ◽  
Response Regulator ◽  
Cell Communication ◽  
Bacterial Pathogen ◽  
Transcriptional Analysis ◽  
Root Colonisation ◽  
Two Systems

ABSTRACT Little is known about the regulatory mechanisms that ensure the survival of the food-borne bacterial pathogen Listeria monocytogenes in the telluric environment and on roots. Earlier studies have suggested a regulatory overlap between the Agr cell–cell communication system and the general stress response regulator σB. Here, we investigated the contribution of these two systems to root colonisation and survival in sterilised and biotic soil. The ability to colonise the roots of the grass Festuca arundinacea was significantly compromised in the double mutant (∆agrA∆sigB). In sterile soil at 25°C, a significant defect was observed in the double mutant, suggesting some synergy between these systems. However, growth was observed and similar population dynamics were shown in the parental strain, ΔagrA and ΔsigB mutants. In biotic soil at 25°C, viability of the parental strain declined steadily over a two-week period highlighting the challenging nature of live soil environments. Inactivation of the two systems further decreased survival. The synergistic effect of Agr and σB was stronger in biotic soil. Transcriptional analysis confirmed the expected effects of the mutations on known Agr- and σB-dependent genes. Data highlight the important role that these global regulatory systems play in the natural ecology of this pathogen.

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