Disruption of the adh (acetoin dehydrogenase) operon has wide-ranging effects on Streptococcus mutans growth and stress response

2022 ◽  
Author(s):  
Peter Zuber ◽  
Michiko M. Nakano ◽  
Jessica K. Kajfasz ◽  
José A. Lemos
Keyword(s):  
Cell Wall ◽  
Transcription Factor ◽  
Dental Caries ◽  
Streptococcus Mutans ◽  
Stress Responses ◽  
Tooth Enamel ◽  
Human Saliva ◽  
Ph Sensitivity ◽  
Growth Defect ◽  
Carbohydrate Utilization

The agent largely responsible for initiating dental caries, Streptococcus mutans produces acetoin dehydrogenase that is encoded by the adh operon. The operon consists of the adhA and B genes (E1 dehydrogenase), adhC (E2 lipoylated transacetylase), adhD (E3 dihydrolipoamide dehydrogenase), and lplA (lipoyl ligase). Evidence is presented that AdhC interacts with SpxA2, a redox-sensitive transcription factor functioning in cell wall and oxidative stress responses. In-frame deletion mutations of adh genes conferred oxygen-dependent sensitivity to slightly alkaline pH (pH 7.2-7.6), within the range of values observed in human saliva. Growth defects were also observed when glucose or sucrose served as major carbon sources. A deletion of the adhC orthologous gene, acoC gene of Streptococcus gordonii , did not result in pH sensitivity or defective growth in glucose and sucrose. The defects observed in adh mutants were partially reversed by addition of pyruvate. Unlike most 2-oxoacid dehydrogenases, the E3 AdhD subunit bears an N-terminal lipoylation domain nearly identical to that of E2 AdhC. Changing the lipoyl domains of AdhC and AdhD by replacing the lipoate attachment residue, lysine to arginine, caused no significant reduction in pH sensitivity but the adhDK43R mutation eliminating the lipoylation site resulted in an observable growth defect in glucose medium. The adh mutations were partially suppressed by a deletion of rex , encoding an NAD + /NADH-sensing transcription factor that represses genes functioning in fermentation. spxA2 adh double mutants show synthetic growth restriction at elevated pH and upon ampicillin treatment. These results suggest a role for Adh in stress management in S. mutans . IMPORTANCE Dental caries is often initiated by Streptococcus mutans , which establishes a biofilm and a low pH environment on tooth enamel surfaces. The current study has uncovered vulnerabilities of S. mutans mutant strains that are unable to produce the enzyme complex, acetoin dehydrogenase (Adh). Such mutants are sensitive to modest increases in pH to 7.2-7.6, within the range of human saliva, while a mutant of a commensal Streptococcal species is resistant. The S. mutans adh strains are also defective in carbohydrate utilization and are hypersensitive to a cell wall-acting antibiotic. The studies suggest that Adh could be a potential target for interfering with S. mutans colonization of the oral environment.

scholarly journals Disruption of L-Rhamnose Biosynthesis Results in Severe Growth Defects in Streptococcus mutans

2019 ◽  
Vol 202 (6) ◽  
Author(s):  
Andrew P. Bischer ◽  
Christopher J. Kovacs ◽  
Roberta C. Faustoferri ◽  
Robert G. Quivey
Keyword(s):  
Cell Wall ◽  
Dental Caries ◽  
Oral Cavity ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Etiologic Agent ◽  
Growth Defect ◽  
Cell Wall Polysaccharide ◽  
Content Type ◽  
Severe Growth

ABSTRACT The rhamnose-glucose cell wall polysaccharide (RGP) of Streptococcus mutans plays a significant role in cell division, virulence, and stress protection. Prior studies examined function of the RGP using strains carrying deletions in the machinery involved in RGP assembly. In this study, we explored loss of the substrate for RGP, l-rhamnose, via deletion of rmlD (encoding the protein responsible for the terminal step in l-rhamnose biosynthesis). We demonstrate that loss of rhamnose biosynthesis causes a phenotype similar to strains with disrupted RGP assembly (ΔrgpG and ΔrgpF strains). Deletion of rmlD not only caused a severe growth defect under nonstress growth conditions but also elevated susceptibility of the strain to acid and oxidative stress, common conditions found in the oral cavity. A genetic complement of the ΔrmlD strain completely restored wild-type levels of growth, whereas addition of exogenous rhamnose did not. The loss of rhamnose production also significantly disrupted biofilm formation, an important aspect of S. mutans growth in the oral cavity. Further, we demonstrate that loss of either rmlD or rgpG results in ablation of rhamnose content in the S. mutans cell wall. Taken together, these results highlight the importance of rhamnose production in both the fitness and the ability of S. mutans to overcome environmental stresses. IMPORTANCE Streptococcus mutans is a pathogenic bacterium that is the primary etiologic agent of dental caries, a disease that affects billions yearly. Rhamnose biosynthesis is conserved not only in streptococcal species but in other Gram-positive, as well as Gram-negative, organisms. This study highlights the importance of rhamnose biosynthesis in RGP production for protection of the organism against acid and oxidative stresses, the two major stressors that the organism encounters in the oral cavity. Loss of RGP also severely impacts biofilm formation, the first step in the onset of dental caries. The high conservation of the rhamnose synthesis enzymes, as well as their importance in S. mutans and other organisms, makes them favorable antibiotic targets for the treatment of disease.

Cell Wall Ultrastructure in Three Strains of a Cariogenic Streptococcus

1971 ◽  
Vol 29 ◽  
pp. 338-339
Author(s):  
M. J. Kramer ◽  
Alan L. Coykendall
Keyword(s):  
Cell Wall ◽  
Dental Caries ◽  
Streptococcus Mutans ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Genetic Heterogeneity ◽  
Morphological Characteristics ◽  
Electron Microscopic ◽  
Dna Reassociation ◽  
Wall Ultrastructure

During the almost 50 years since Streptococcus mutans was first suggested as a factor in the etiology of dental caries, a multitude of studies have confirmed the cariogenic potential of this organism. Streptococci have been isolated from human and animal caries on numerous occasions and, with few exceptions, they are not typable by the Lancefield technique but are relatively homogeneous in their biochemical reactions. An analysis of the guanine-cytosine (G-C) composition of the DNA from strains K-1-R, NCTC 10449, and FA-1 by one of us (ALC) revealed significant differences and DNA-DNA reassociation experiments indicated that genetic heterogeneity existed among the three strains. The present electron microscopic study had as its objective the elucidation of any distinguishing morphological characteristics which might further characterize the respective strains.

scholarly journals Antibiofilm Activity of Mangosteen (Garcinia mangostana L.) Flavonoids against Streptococcus mutans Bacteria

2020 ◽  
Vol 10 (2) ◽  
pp. 48
Author(s):  
Sri Kunarti ◽  
Aulia Ramadhani ◽  
Laskmiari Setyowati
Keyword(s):  
Dental Caries ◽  
Streptococcus Mutans ◽  
Tooth Enamel ◽  
Tooth Surface ◽  
Control Group ◽  
Antibiofilm Activity ◽  
Garcinia Mangostana ◽  
Control Group Design ◽  
Biofilm Inhibition ◽  
Significant Difference

Background: Dental caries is one of the most common infectious diseases and often occurs in the community caused by bacteria. Attached bacteria in the tooth surface for a long time will form a biofilm and will lead to demineralization characterized by damage in the structure of the tooth enamel. The bacteria that cause dental caries and can form biofilms is Streptococcus mutans. The bacteria inside biofilms are more resistant to antibacterial agents. Flavonoids in mangosteen pericarp extract can be a cleaner alternative for the anti-biofilm cavity that has properties against Streptococcus mutans. Purpose: To determine the activity of flavonoids in mangosteen pericarp extract at a certain concentration against Streptococcus mutans bacteria. Methods: This study was a laboratory experimental study with a post-test only control group design. Streptococcus mutans were diluted according to the Mc Farland dilution standard 106 in Tryptic Soy Broth (TSB) medium and put in a flexible U-bottom microtiter plate. Then it was incubated for 5x24 hours and checked using crystal violet simple staining to see the formation of biofilms. Flavonoid extract of mangosteen pericarp performed serial dilution in a concentration of 100%, 50%, 25%, 12.5%, 6.25%, 3.125%, 1.56%, and 0.78% was added, and the incubation process were conducted for 1x24 hours. OD (Optical Density) readings were done with a wavelength of 595 nm. Results: There was a significant difference between the test groups and the positive control group. The concentration of 100% had the anti-biofilm activity and showed the value of the highest percentage of inhibition, whilst the concentration of 0.78% showed a minimum biofilm inhibition concentration. The results were demonstrated by a statistical analysis test. Conclusion: Flavonoid extract of mangosteen pericarp at a certain concentration has anti-biofilm activity against Streptococcus mutans biofilm.

scholarly journals Cloning, Expression, Purification, and Preliminary Characterization of Single-Crystal X-Ray Diffraction of Glucosyltransferase B of Streptococcus mutans

2019 ◽  
Vol 14 (5) ◽  
pp. 1934578X1984933
Author(s):  
Joshua L. Mieher ◽  
Norbert Schormann ◽  
Manisha Patel ◽  
Hui Wu ◽  
Champion Deivanayagam
Keyword(s):  
Dental Caries ◽  
Oral Cavity ◽  
Single Crystal ◽  
Streptococcus Mutans ◽  
Tooth Enamel ◽  
Tooth Surface ◽  
X Ray Diffraction ◽  
Persistent Disease ◽  
X Ray

Dental caries characterized by acid damage of tooth enamel is a persistent disease that begins with the formation of biofilms on the tooth surface. The secreted glucosyltransferases enable Streptococcus mutans to synthesize extracellular glucan polymers using ingested starch within the oral cavity, which eventually results in the production of acid, a contributing factor to cariogenesis. In this paper, we report the cloning, expression, purification, crystallization, and preliminary X-ray diffraction characterization of glucosyltransferase B.

A Study on Dental Caries and Dental Plaques Caused by Streptococcus Mutans, of Patients at Border Guard Hospital Dhaka, Peelkhana

2020 ◽  
Vol 38 (3) ◽  
pp. 121-125
Author(s):  
Rezina Jasmine ◽  
Khairul Islam Mridha ◽  
Mohammad Kamal Akhter ◽  
Dilruba Sharmin
Keyword(s):  
Dental Caries ◽  
Streptococcus Mutans ◽  
Tooth Enamel ◽  
Special Kind ◽  
Streptococcus Viridans ◽  
Clinical Samples ◽  
Cross Sectional ◽  
Pathology Department ◽  
Dental Plaques ◽  
Etiological Agents

Background: Dental caries is one of the most common chronic infectious diseases in the world. The acids generated through the fermentation of sugar by the microorganisms in dental plaque can decalcify the superficial layers of tooth enamel and can initiate dental caries. Streptococcus mutans have been proposed as the main etiological agents of dental caries .The aim of this study is to identify the main etiological agents of dental caries and plaque which are supposed to be Streptococcus mutans as correlating microorganism. Materials and Methods: This cross sectional study was carried out in the Pathology department of Border Guard Hospital, Peelkhana, Dhaka during the period of 1st October, 2018 to 3IST December,2018. Study population was newly enrolled soldiers and their families as male ,female and children in BGB. A total of 50 clinical samples were included in this study. The samples were collected from the Dental outdoor patient department and all laboratory tests were performed at Pathology department of aforementioned hospital. After performing all possible microbiological tests for bacterial isolation, results were recorded. Results: Among 50 samples, 46(92%) samples are considered to be positive for Streptococcus viridans and 27(54%) isolates are identified as Streptococci mutans according to ability of producing special kind of exopolysaccharide, lactic acid formation and high salt tolerance tests. Associated organisms (32%) like candida were present in 15(30%) samples and other bacterial colonies were present in 31(62%) samples, along with Streptococcus viridans. Conclusion: The finding of this study will help the dentists to treat the patients with chronic caries, dental plaques as they pose the gravest threat when they settle down on damaged heart valves, cause subacute bacterial endocarditis and other infections in various sites including mouth, joints, skin, muscle, and central nervous system after tooth extraction or any other invasive procedure J Bangladesh Coll Phys Surg 2020; 38(3): 121-125

Lemon myrtle extract inhibits lactate production by Streptococcus mutans

2021 ◽  
Vol 85 (10) ◽  
pp. 2185-2190
Author(s):  
Yukinori Yabuta ◽  
Yui Sato ◽  
Arisu Miki ◽  
Ryuta Nagata ◽  
Tomohiro Bito ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Dental Caries ◽  
Oral Cavity ◽  
Streptococcus Mutans ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Tooth Enamel ◽  
Lactate Production ◽  
Tooth Decay ◽  
Lactate Dehydrogenase Activity

ABSTRACT Backhousia citriodora (lemon myrtle) extract has been found to inhibit glucansucrase activity, which plays an important role in biofilm formation by Streptococcus mutans. In addition to glucansucrase, various virulence factors in S. mutans are involved in the initiation of caries. Lactate produced by S. mutans demineralizes the tooth enamel. This study investigated whether lemon myrtle extract can inhibit S. mutans lactate production. Lemon myrtle extract reduced the glycolytic pH drop in S. mutans culture and inhibited lactate production by at least 46%. Ellagic acid, quercetin, hesperetin, and myricetin, major polyphenols in lemon myrtle, reduced the glycolytic pH drop and lactate production, but not lactate dehydrogenase activity. Furthermore, these polyphenols reduced the viable S. mutans cell count. Thus, lemon myrtle extracts may inhibit S. mutans-mediated acidification of the oral cavity, thereby preventing dental caries and tooth decay.

scholarly journals Isolation and Characterization of anti-Streptococcus Mutans Phage as a Possible Treatment Agent for Caries

2021 ◽  
Author(s):  
Hadar Ben Zaken ◽  
Reut Kraitman ◽  
Shunit Coppenhagen-Glazer ◽  
Leron Khalifa ◽  
Sivan Alkalay-Oren ◽  
...  
Keyword(s):  
Dental Caries ◽  
Streptococcus Mutans ◽  
Pathogenic Bacteria ◽  
Antibacterial Effect ◽  
Antibacterial Properties ◽  
Human Saliva ◽  
Whole Genome Sequence ◽  
Isolation And Characterization

Streptococcus mutans is a key bacterium in dental caries- one of the most prevalent chronic infectious diseases. Conventional treatment both fails to specifically target the pathogenic bacteria and at-tempts to eradicate commensal bacteria as well. Thus, caries remains one of most common and challenging diseases. The use of bacterial viruses as anti-bacterial agents, is gaining interest worldwide. Hardly any phages were described against S. mutans. The objective of this study was to isolate anti-S. mutans phages and to characterize their antimi-crobial properties. Human saliva samples were filtered and screened for potential phages. Standard double-layered agar method was used for isolation. Whole genome sequence analysis and morphology visualization by TEM, were used for anti-S. mutans phage identification. Antibacterial properties were evaluated using clinical strains and ATCC strains of S. mutans in various states. Antibacterial effect was also tested on human cariogenic dentin. One phage against S. mutans was isolated and termed SMHBZ8. This phage showed effective lytic activity in vitro against both planktonic and biofilm S. mutans cultures. Moreover, the phage showed antibacterial effect when used on cariogenic dentin. The isolation and characterization of SMHBZ8 may be the first step in developing a potential phage therapy for dental caries.

scholarly journals Isolation and Characterization of Streptococcus mutans Phage as a Possible Treatment Agent for Caries

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 825
Author(s):  
Hadar Ben-Zaken ◽  
Reut Kraitman ◽  
Shunit Coppenhagen-Glazer ◽  
Leron Khalifa ◽  
Sivan Alkalay-Oren ◽  
...  
Keyword(s):  
Dental Caries ◽  
Streptococcus Mutans ◽  
Conventional Treatment ◽  
Pathogenic Bacteria ◽  
Phage Therapy ◽  
Antibacterial Properties ◽  
Human Saliva ◽  
Isolation And Characterization ◽  
Treatment Agent

Streptococcus mutans is a key bacterium in dental caries, one of the most prevalent chronic infectious diseases. Conventional treatment fails to specifically target the pathogenic bacteria, while tending to eradicate commensal bacteria. Thus, caries remains one of the most common and challenging diseases. Phage therapy, which involves the use of bacterial viruses as anti-bacterial agents, has been gaining interest worldwide. Nevertheless, to date, only a few phages have been isolated against S. mutans. In this study, we describe the isolation and characterization of a new S. mutans phage, termed SMHBZ8, from hundreds of human saliva samples that were collected, filtered, and screened. The SMHBZ8 genome was sequenced and analyzed, visualized by TEM, and its antibacterial properties were evaluated in various states. In addition, we tested the lytic efficacy of SMHBZ8 against S. mutans in a human cariogenic dentin model. The isolation and characterization of SMHBZ8 may be the first step towards developing a potential phage therapy for dental caries.

scholarly journals A 60-Kilodalton Immunodominant Glycoprotein Is Essential for Cell Wall Integrity and the Maintenance of Cell Shape inStreptococcus mutans

2001 ◽  
Vol 69 (11) ◽  
pp. 6987-6998 ◽  
Author(s):  
Jean-San Chia ◽  
Lan Yi Chang ◽  
Chia-Tung Shun ◽  
Ying-Ying Chang ◽  
Jen-Yang Chen
Keyword(s):  
Cell Wall ◽  
Molecular Mass ◽  
Streptococcus Mutans ◽  
Cell Shape ◽  
Lectin Binding ◽  
Growth Defect ◽  
Expression Library ◽  
Immunodominant Antigen ◽  
Insertional Inactivation

ABSTRACT We have demonstrated previously by Western blotting that in naturally sensitized humans, the serum or salivary antibody response toStreptococcus mutans was directed predominantly to a protein antigen with a size of approximately 60-kDa. To identify this immunodominant antigen, specific serum antibodies were eluted from immunoblots and five positive clones with inserts ranging in length from 3 to 8 kb from identical chromosomal loci were obtained by screening a genomic expression library of Streptococcus mutans GS-5. Amino acid sequencing established the identity of this immunodominant antigen, a 60-kDa immunodominant glycoprotein (IDG-60), to be a cell wall-associated general stress protein GSP-781, which was originally predicted to have a molecular mass of approximately 45 kDa based on the derived nucleotide sequence. Discrepancy in the molecular mass was also observed in recombinant his-tagged IDG-60 (rIDG-60) expressed from Escherichia coli. Glycosylation, consisting of sialic acid, mannose galactose, and N-acetylgalactosamine, was detected by lectin binding to IDG-60 in cell wall extracts from S. mutans and rIDG-60 expressed in vivo or translated in vitro. Despite the presence of multiple Asn or Ser or Thr glycosylation sites, IDG-60 was resistant to the effect of N-glycosidase F and multiple O-glycosidase molecules but not to β-galactosidase. Insertional inactivation of the gene encoding IDG-60, sagA, resulted in a retarded growth rate, destabilization of the cell wall, and pleiomorphic cell shape with multifold ingrowth of cell wall. In addition, distinct from the parental GS-5 strain, the isogenic mutant GS-51 was unable to survive the challenge of low pH and high osmotic pressure or high temperature. Expression of the wild-type gene in trans within GS-51 from plasmid pDL277 complemented the growth defect and restored normal cell shape. These results suggested that IDG-60 is essential for maintaining the integrity of the cell wall and the uniformity of cell shape, both of which are indispensable for bacteria survival under stress conditions.

scholarly journals Efg1 and Cas5 Orchestrate Cell Wall Damage Response to Caspofungin in Candida albicans

2020 ◽  
Author(s):  
Kang Xiong ◽  
Chang Su ◽  
Qiangqiang Sun ◽  
Yang Lu
Keyword(s):  
Cell Wall ◽  
Transcription Factor ◽  
Candida Albicans ◽  
Transcriptional Response ◽  
Wall Stress ◽  
Growth Defect ◽  
Transcriptional Responses ◽  
Cell Wall Stress ◽  
Cell Wall Damage

Echinocandins are recommended as the first-line drugs for the treatment of systemic candidiasis. Cas5 is a key transcription factor involved in the response to cell wall damage induced by echinocandins. Here, through a genetic screen, we report the identification of a second transcription factor Efg1 that is also crucial for proper transcriptional responses to echinocandins. Like CAS5, deletion of EFG1 confers hypersensitivity to caspofungin. Efg1 is required for the induction of CAS5 in response to caspofungin. However, ectopically expressed CAS5 cannot rescue the growth defect of efg1 mutant in caspofungin-containing medium. Deleting EFG1 in the cas5 mutant exacerbates the cell wall stress upon caspofungin addition and renders caspofungin-resistant Candida albicans responsive to treatment. Genome-wide transcription profiling of efg1/efg1 and cas5/cas5 using a RNA-Seq indicates that Efg1 and Cas5 co-regulate numbers of caspofungin-responsive genes expression, but they also independently control some genes induction. We further show that Efg1 interacts with Cas5 by yeast two-hybrid and in vivo immunoprecipitation in the presence or absence of caspofungin. Importantly, Efg1 and Cas5 bind to some caspofungin-responsive genes promoter to coordinately activate their expression. Thus, we demonstrate that Efg1, together with Cas5, controls the transcriptional response to cell wall stress induced by caspofungin.

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