scholarly journals The Streptococcus mutans Cid and Lrg systems modulate virulence traits in response to multiple environmental signals

Microbiology ◽  
2010 ◽  
Vol 156 (10) ◽  
pp. 3136-3147 ◽  
Author(s):  
Sang-Joon Ahn ◽  
Kelly C. Rice ◽  
Janneth Oleas ◽  
Kenneth W. Bayles ◽  
Robert A. Burne
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Protein A ◽  
Virulence Gene ◽  
Structural Features ◽  
Exponential Phase ◽  
Late Exponential Phase ◽  
Environmental Signals ◽  
Virulence Gene Expression ◽  
Virulence Traits

The tight control of autolysis by Streptococcus mutans is critical for proper virulence gene expression and biofilm formation. A pair of dicistronic operons, SMU.575/574 (lrgAB) and SMU.1701/1700 (designated cidAB), encode putative membrane proteins that share structural features with the bacteriophage-encoded holin family of proteins, which modulate host cell lysis during lytic infection. Analysis of S. mutans lrg and cid mutants revealed a role for these operons in autolysis, biofilm formation, glucosyltransferase expression and oxidative stress tolerance. Expression of lrgAB was repressed during early exponential phase and was induced over 1000-fold as cells entered late exponential phase, whereas cidAB expression declined from early to late exponential phase. A two-component system encoded immediately upstream of lrgAB (LytST) was required for activation of lrgAB expression, but not for cid expression. In addition to availability of oxygen, glucose levels were revealed to affect lrg and cid transcription differentially and significantly, probably through CcpA (carbon catabolite protein A). Collectively, these findings demonstrate that the Cid/Lrg system can affect several virulence traits of S. mutans, and its expression is controlled by two major environmental signals, oxygen and glucose. Moreover, cid/lrg expression is tightly regulated by LytST and CcpA.

scholarly journals Effects of resveratrol on cariogenic virulence properties of Streptococcus mutans

2020 ◽  
Author(s):  
Jinheng Li ◽  
Tiantian Wu ◽  
Weiwei Peng ◽  
yaqin zhu
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Acid Production ◽  
Virulence Gene ◽  
Acid Tolerance ◽  
Extracellular Polysaccharide ◽  
Inhibitory Effect ◽  
Water Soluble ◽  
Virulence Gene Expression ◽  
Virulence Properties

Abstract Background: Streptococcus mutans is the principal etiological agent of human dental caries. The major virulence factors of S. mutans are acid production, acid tolerance, extracellular polysaccharide (EPS) synthesis and biofilm formation. The aim of this study is to evaluate the effect of resveratrol, a natural compound, on virulence properties of S. mutans . Results: Resveratrol at sub-MIC levels significantly decreased acid production and acid tolerance, inhibited synthesis of water-soluble polysaccharide and water-insoluble polysaccharide, compromised biofilm formation. Related virulence gene expression ( ldh, relA, gtfC, comDE ) was down-regulated with increasing concentrations of resveratrol. Conclusions : Resveratrol has an inhibitory effect on S. mutans cariogenic virulence properties and it represents a promising anticariogenic agent. Keywords : resveratrol, Streptococcus mutans , acidogenicity, aciduricity, extracellular polysaccharide, biofilm

scholarly journals Effects of resveratrol on cariogenic virulence properties of Streptococcus mutans

2020 ◽  
Author(s):  
Jinheng Li ◽  
Yaqin Zhu ◽  
Tiantian Wu ◽  
Weiwei Peng
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Acid Production ◽  
Virulence Gene ◽  
Acid Tolerance ◽  
Extracellular Polysaccharide ◽  
Inhibitory Effect ◽  
Water Soluble ◽  
Virulence Gene Expression ◽  
Virulence Properties

Abstract Background: Streptococcus mutans is the principal etiological agent of human dental caries. The major virulence factors of S. mutans are acid production, acid tolerance, extracellular polysaccharide (EPS) synthesis and biofilm formation. The aim of this study is to evaluate the effect of resveratrol, a natural compound, on virulence properties of S. mutans . Methods: The effect of resveratrol on acidogenicity was investigated by pH drop and lactate dehydrogenase (LDH) assay, on aciduricity through survival rate at pH 5.0 and F-ATPase assay, on EPS synthesis (including water-soluble polysaccharide and water-insoluble polysaccharide) by quantitative measurement, on biofilm formation by crystal violet assay and structure observation. The expression of related virulence genes was also detected . Results: Resveratrol at sub-MIC levels can significantly decrease acid production, acid tolerance, EPS synthesis and biofilm formation. Related virulence gene expression ( ldh , relA , gtfC , comDE ) was down-regulated with increasing concentrations of resveratrol. Conclusion: Resveratrol has an inhibitory effect on S. mutans cariogenic virulence properties and it represents a promising anticariogenic agent .

scholarly journals Effects of Oxygen on Virulence Traits of Streptococcus mutans

2007 ◽  
Vol 189 (23) ◽  
pp. 8519-8527 ◽  
Author(s):  
Sang-Joon Ahn ◽  
Zezhang T. Wen ◽  
Robert A. Burne
Keyword(s):  
Streptococcus Mutans ◽  
Regulatory Networks ◽  
Nadh Oxidase ◽  
Tricarboxylic Acid Cycle ◽  
Virulence Gene ◽  
Virulence Gene Expression ◽  
Virulence Traits ◽  
Oral Biofilms ◽  
Underlying Mechanisms ◽  
Upregulated Genes

ABSTRACT Oxygen profoundly affects the composition of oral biofilms. Recently, we showed that exposure of Streptococcus mutans to oxygen strongly inhibits biofilm formation and alters cell surface biogenesis. To begin to dissect the underlying mechanisms by which oxygen affects known virulence traits of S. mutans, transcription profiling was used to show that roughly 5% of the genes of this organism are differentially expressed in response to aeration. Among the most profoundly upregulated genes were autolysis-related genes and those that encode bacteriocins, the ClpB protease chaperone subunit, pyruvate dehydrogenase, the tricarboxylic acid cycle enzymes, NADH oxidase enzymes, and certain carbohydrate transporters and catabolic pathways. Consistent with our observation that the ability of S. mutans to form biofilms was severely impaired by oxygen exposure, transcription of the gtfB gene, which encodes one of the primary enzymes involved in the production of water-insoluble, adhesive glucan exopolysaccharides, was down-regulated in cells growing aerobically. Further investigation revealed that transcription of gtfB, but not gtfC, was responsive to oxygen and that aeration causes major changes in the amount and degree of cell association of the Gtf enzymes. Moreover, inactivation of the VicK sensor kinase affected the expression and localization the GtfB and GtfC enzymes. This study provides novel insights into the complex transcriptional and posttranscriptional regulatory networks used by S. mutans to modulate virulence gene expression and exopolysaccharide production in response to changes in oxygen availability.

scholarly journals Effects of resveratrol on cariogenic virulence properties of Streptococcus mutans

2019 ◽  
Author(s):  
Jinheng Li ◽  
Tiantian Wu ◽  
Weiwei Peng ◽  
Yaqin Zhu
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Acid Production ◽  
Virulence Gene ◽  
Acid Tolerance ◽  
Extracellular Polysaccharide ◽  
Inhibitory Effect ◽  
Water Soluble ◽  
Virulence Gene Expression ◽  
Virulence Properties

Abstract Background: Streptococcus mutans is the principal etiological agent of human dental caries. The major virulence factors of S. mutans are acid production, acid tolerance, extracellular polysaccharide (EPS) synthesis and biofilm formation. The aim of this study is to evaluate the effect of resveratrol, a natural compound, on virulence properties of S. mutans . Methods: The effect of resveratrol on acidogenicity was investigated by pH drop and lactate dehydrogenase (LDH) assay, on aciduricity through survival rate at pH 5.0 and F-ATPase assay, on EPS synthesis (including water-soluble polysaccharide and water-insoluble polysaccharide) by quantitative measurement, on biofilm formation by crystal violet assay and structure observation. The expression of related virulence genes was also detected . Results: Resveratrol at sub-MIC levels can significantly decrease acid production, acid tolerance, EPS synthesis and biofilm formation. Related virulence gene expression ( ldh , relA , gtfC , comDE ) was down-regulated with increasing concentrations of resveratrol. Conclusion: Resveratrol has an inhibitory effect on S. mutans cariogenic virulence properties and it represents a promising anticariogenic agent .

scholarly journals Norlichexanthone Reduces Virulence Gene Expression and Biofilm Formation in Staphylococcus aureus

PLoS ONE ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. e0168305 ◽  
Author(s):  
Mara Baldry ◽  
Anita Nielsen ◽  
Martin S. Bojer ◽  
Yu Zhao ◽  
Cathrine Friberg ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Virulence Gene ◽  
Virulence Gene Expression

VicRK and CovR polymorphisms in Streptococcus mutans strains associated with cardiovascular infections

2021 ◽  
Vol 70 (12) ◽  
Author(s):  
Letícia T. Oliveira ◽  
Lívia A. Alves ◽  
Erika N. Harth-Chu ◽  
Ryota Nomura ◽  
Kazuhiko Nakano ◽  
...  
Keyword(s):  
Streptococcus Mutans ◽  
Type Species ◽  
Virulence Gene ◽  
Common Species ◽  
Oral Microbiome ◽  
Nucleotide Polymorphisms ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Coding Regions ◽  
Link Type

Introduction. Streptococcus mutans , a common species of the oral microbiome, expresses virulence genes promoting cariogenic dental biofilms, persistence in the bloodstream and cardiovascular infections. Gap statement. Virulence gene expression is variable among S. mutans strains and controlled by the transcription regulatory systems VicRK and CovR. Aim. This study investigates polymorphisms in the vicRK and covR loci in S. mutans strains isolated from the oral cavity or from the bloodstream, which were shown to differ in expression of covR, vicRK and downstream genes. Methodology. The transcriptional activities of covR, vicR and vicK were compared by RT-qPCR between blood and oral strains after exposure to human serum. PCR-amplified promoter and/or coding regions of covR and vicRK of 18 strains (11 oral and 7 blood) were sequenced and compared to the reference strain UA159. Results. Serum exposure significantly reduced covR and vicR/K transcript levels in most strains (P<0.05), but reductions were higher in oral than in blood strains. Single-nucleotide polymorphisms (SNPs) were detected in covR regulatory and coding regions, but SNPs affecting the CovR effector domain were only present in two blood strains. Although vicR was highly conserved, vicK showed several SNPs, and SNPs affecting VicK regions important for autokinase activity were found in three blood strains. Conclusions. This study reveals transcriptional and structural diversity in covR and vicR/K, and identifies polymorphisms of functional relevance in blood strains, indicating that covR and vicRK might be important loci for S. mutans adaptation to host selective pressures associated with virulence diversity.

scholarly journals Staphylococcus aureus CcpA Affects Virulence Determinant Production and Antibiotic Resistance

2006 ◽  
Vol 50 (4) ◽  
pp. 1183-1194 ◽  
Author(s):  
Kati Seidl ◽  
Martin Stucki ◽  
Martin Ruegg ◽  
Christiane Goerke ◽  
Christiane Wolz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Capsular Polysaccharide ◽  
Protein A ◽  
Virulence Gene ◽  
Exponential Growth Phase ◽  
Virulence Determinants ◽  
Resistance Level ◽  
Virulence Gene Expression ◽  
Oxacillin Resistance

ABSTRACT Carbon catabolite protein A (CcpA) is known to function as a major regulator of gene expression in different gram-positive organisms. Deletion of the ccpA homologue (saCOL1786) in Staphylococcus aureus was found to affect growth, glucose metabolization, and transcription of selected virulence determinants. In liquid culture, deletion of CcpA decreased the growth rate and yield; however, the effect was only transient during the exponential-growth phase as long as glucose was present in the medium. Depletion of glucose and production of lactate was delayed, while the level of excretion of acetate was less affected and was even higher in the mutant culture. On solid medium, in contrast, growth of the ΔccpA mutant resulted in smaller colonies containing a lower number of CFU per colony. Deletion of CcpA had an effect on the expression of important virulence factors of S. aureus by down-regulating RNAIII, the effector molecule of the agr locus, and altering the transcription patterns of hla, encoding α-hemolysin, and spa, encoding protein A. CcpA inactivation markedly reduced the oxacillin resistance levels in the highly methicillin-resistant S. aureus strain COLn and the teicoplanin resistance level in a glycopeptide-intermediate-resistant S. aureus strain. The presence of CcpA in the capsular polysaccharide serotype 5 (CP5)-producing strain Newman abolished capsule formation and decreased cap operon transcription in the presence of glucose. The staphylococcal CcpA thus not only is involved in the regulation of carbon metabolism but seems to function as a modulator of virulence gene expression as well.

scholarly journals Association among biofilm formation, virulence gene expression, and antibiotic resistance in Proteus mirabilis isolates from diarrhetic animals in northeast China

2020 ◽  
Author(s):  
Yadong Sun ◽  
Shanshan Wen ◽  
Lili Zhao ◽  
Qiqi Xia ◽  
Yue Pan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Northeast China ◽  
Virulence Gene ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Virulence Gene Expression ◽  
Biofilm Production ◽  
High Level

Abstract Background The aim of this study was to investigate the association among biofilm formation, virulence gene expression, and antibiotic resistance in P. mirabilis isolates collected from diarrhetic animals (n = 176) in northeast China between September 2014 and October 2016. Results Approximately 92.05% of the isolates were biofilm producers, whereas 7.95% of the isolates were non-producers. The prevalence of virulence genes in biofilm producers was significantly higher than that in non-producers. Biofilm production was significantly associated with the expression of ureC , zapA , rsmA , hmpA , mrpA , atfA , and pmfA ( P < 0.05). Drug susceptibility tests revealed that approximately 76.7% of the isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR). Biofilm production was significantly associated with resistance to doxycycline, tetracycline, sulfamethoxazole, kanamycin, and cephalothin ( P < 0.05). Although the pathogenicity of the biofilm producers was stronger than that of the non-producers, the biofilm-forming ability of the isolates was not significantly associated with morbidity and mortality in mice ( P > 0.05). Conclusion Our findings suggested that a high level of multidrug resistance in diarrhetic animals infected with P. mirabilis in northeast China.The results of this study indicated that the positive rates of the genes expressed by biofilm-producing P. mirabilis isolates were significantly higher than those expressed by non-producing isolates.

scholarly journals Photo sensing and quorum sensing are integrated to control bacterial group behaviors

2019 ◽  
Author(s):  
Sampriti Mukherjee ◽  
Matthew Jemielita ◽  
Vasiliki Stergioula ◽  
Mikhail Tikhonov ◽  
Bonnie L. Bassler
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Response Regulator ◽  
Sensory Information ◽  
Virulence Gene ◽  
Component System ◽  
Virulence Gene Expression ◽  
Bacterial Phyla ◽  
Expression Of Genes ◽  
Genes Encoding

ABSTRACTPseudomonas aeruginosa transitions between the free-swimming state and the sessile biofilm mode during its pathogenic lifestyle. We show that quorum sensing represses P. aeruginosa biofilm formation and virulence by activating expression of genes encoding the KinB-AlgB two-component system. Phospho-AlgB represses biofilm and virulence genes, while KinB dephosphorylates, and thereby, inactivates AlgB. We discover that the photoreceptor BphP is the kinase that, in response to light, phosphorylates and activates AlgB. Indeed, exposing P. aeruginosa to light represses biofilm formation and virulence gene expression. To our knowledge, P. aeruginosa was not previously known to detect light. The KinB-AlgB-BphP module is present in all Pseudomonads, and we demonstrate that AlgB is the cognate response regulator for BphP in diverse bacterial phyla. We propose that KinB-AlgB-BphP constitutes a “three-component” system and AlgB is the node at which varied sensory information is integrated. This study sets the stage for light-mediated control of P. aeruginosa infectivity.

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