Function of the Pyruvate Oxidase-Lactate Oxidase Cascade in Interspecies Competition between Streptococcus oligofermentans and Streptococcus mutans

Liu, Lei; Tong, Huichun; Dong, Xiuzhu

doi:10.1128/aem.07539-11

Cited by 50 publications

(62 citation statements)

References 58 publications

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“…Pyruvate oxidase activity was determined by measuring the production of acetyl phosphate (AcP) (57,58). Briefly, the reaction mixture consisted of 0.45 ml of the permeabilized cell suspension and 0.45 ml of a solution containing 50 mM potassium phosphate buffer (pH 6.0), 10 M MgCl 2 , 0.2 M thiamine pyrophosphate (Sigma), 50 mM potassium pyruvate, and 12 M flavin adenine dinucleotide (FAD; Sigma).…”

Section: Methodsmentioning

confidence: 99%

A Highly Arginolytic Streptococcus Species That Potently Antagonizes Streptococcus mutans

Huang

Palmer

Ahn

et al. 2016

Appl Environ Microbiol

112

128

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The ability of certain oral biofilm bacteria to moderate pH through arginine metabolism by the arginine deiminase system (ADS) is a deterrent to the development of dental caries. Here, we characterize a novel Streptococcus strain, designated strain A12, isolated from supragingival dental plaque of a caries-free individual. A12 not only expressed the ADS pathway at high levels under a variety of conditions but also effectively inhibited growth and two intercellular signaling pathways of the dental caries pathogen Streptococcus mutans. A12 produced copious amounts of H 2 O 2 via the pyruvate oxidase enzyme that were sufficient to arrest the growth of S. mutans. A12 also produced a protease similar to challisin (Sgc) of Streptococcus gordonii that was able to block the competence-stimulating peptide (CSP)-ComDE signaling system, which is essential for bacteriocin production by S. mutans. Wild-type A12, but not an sgc mutant derivative, could protect the sensitive indicator strain Streptococcus sanguinis SK150 from killing by the bacteriocins of S. mutans. A12, but not S. gordonii, could also block the XIP (comX-inducing peptide) signaling pathway, which is the proximal regulator of genetic competence in S. mutans, but Sgc was not required for this activity. The complete genome sequence of A12 was determined, and phylogenomic analyses compared A12 to streptococcal reference genomes. A12 was most similar to Streptococcus australis and Streptococcus parasanguinis but sufficiently different that it may represent a new species. A12-like organisms may play crucial roles in the promotion of stable, health-associated oral biofilm communities by moderating plaque pH and interfering with the growth and virulence of caries pathogens. Dental caries remains an enormous health problem worldwide (1-4). The current view of the initiation and progression of dental caries is one of a dynamic process in which the normal balance between the complex environmental factors that control demineralization and remineralization of the tooth is disrupted in a way that favors the loss of tooth mineral. Demineralization is driven primarily by microbial fermentation of carbohydrates to organic acids, which can lower the pH of oral biofilms to the extent that there is significant dissolution of tooth mineral. Alkalization of oral biofilms occurs during fasting periods and is attributable to salivary clearance of acids, buffering of oral biofilms by host-derived and microbially derived components, and the production of basic compounds by microbial metabolism of amino acids, polyamines, urea, and other compounds (5-10). Development or worsening of a carious lesion occurs when acid-mediated enamel demineralization predominates and is associated with changes in the composition and biochemical activities of the associated microflora. Evidence is now accumulating from a variety of sources that supports that alkali generation, particularly in the form of ammonia, plays a major role in pH homeostasis in oral biofilms and inhibits the initiation and progre...

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Section: Methodsmentioning

confidence: 99%

A Highly Arginolytic Streptococcus Species That Potently Antagonizes Streptococcus mutans

Huang

Palmer

Ahn

et al. 2016

Appl Environ Microbiol

112

128

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“…During aerobic growth, they not only convert O 2 Ϫ to H 2 O 2 via SOD, but produce H 2 O 2 catalyzed by various oxidases (20)(21)(22)(23)(24). However, they do not possess the main H 2 O 2 -degrading enzyme catalase, and the identified peroxidases, such as AhpC/AhpF and glutathione peroxidase, also contribute little to H 2 O 2 resistance in streptococci (20,25).…”

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confidence: 99%

“…Streptococcus oligofermentans is isolated from noncariogenic dental plaque in humans (31). It generates copious H 2 O 2 via multiple pathways (22)(23)(24) and inhibits the growth of the dental caries pathogen Streptococcus mutans. Compared to other streptococci, S. oligofermentans has the greatest H 2 O 2 tolerance (32), making it a model organism in studying bacterial anti-oxidative-stress mechanisms.…”

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confidence: 99%

PerR-Regulated Manganese Ion Uptake Contributes to Oxidative Stress Defense in an Oral Streptococcus

Wang

Tong

Dong

2014

Appl Environ Microbiol

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“…S. mutans has evolved several mechanisms to respond to acid stress, including upregulation of F-ATPase activity (7,8), reduced phosphotransferase activity (9,10), cytosolic alkalinization through the use of the agmatine deiminase system (5,11) or malolactic fermentation (12), and alteration of membrane fatty acid composition (13,14). In addition to acid stress, S. mutans must also cope with exposure to oxidative stress, created by diatomic environmental oxygen present in the oral cavity, as well as copious amounts of H 2 O 2 produced by competing oral microflora in an attempt to thwart persistence and proliferation of S. mutans and other cariogenic bacteria (15)(16)(17)(18)(19). S. mutans encodes several enzymes important in eliminating potentially dangerous reactive oxygen species (ROS) (20).…”

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confidence: 99%

Streptococcus mutans NADH Oxidase Lies at the Intersection of Overlapping Regulons Controlled by Oxygen and NAD ⁺ Levels

et al. 2014

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c NADH oxidase (Nox, encoded by nox) is a flavin-containing enzyme used by the oral pathogen Streptococcus mutans to reduce diatomic oxygen to water while oxidizing NADH to NAD ؉ . The critical nature of Nox is 2-fold: it serves to regenerate NAD ؉ , a carbon cycle metabolite, and to reduce intracellular oxygen, preventing formation of destructive reactive oxygen species (ROS). As oxygen and NAD؉ have been shown to modulate the activity of the global transcription factors Spx and Rex, respectively, Nox is potentially poised at a critical junction of two stress regulons. In this study, microarray data showed that either addition of oxygen or loss of nox resulted in altered expression of genes involved in energy metabolism and transport and the upregulation of genes encoding ROS-metabolizing enzymes. Loss of nox also resulted in upregulation of several genes encoding transcription factors and signaling molecules, including the redox-sensing regulator gene rex. Characterization of the nox promoter revealed that nox was regulated by oxygen, through SpxA, and by Rex. These data suggest a regulatory loop in which the roles of nox in reduction of oxygen and regeneration of NAD ؉ affect the activity levels of Spx and Rex, respectively, and their regulons, which control several genes, including nox, crucial to growth of S. mutans under conditions of oxidative stress.

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Function of the Pyruvate Oxidase-Lactate Oxidase Cascade in Interspecies Competition between Streptococcus oligofermentans and Streptococcus mutans

Cited by 50 publications

References 58 publications

A Highly Arginolytic Streptococcus Species That Potently Antagonizes Streptococcus mutans

A Highly Arginolytic Streptococcus Species That Potently Antagonizes Streptococcus mutans

PerR-Regulated Manganese Ion Uptake Contributes to Oxidative Stress Defense in an Oral Streptococcus

Streptococcus mutans NADH Oxidase Lies at the Intersection of Overlapping Regulons Controlled by Oxygen and NAD ⁺ Levels

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Function of the Pyruvate Oxidase-Lactate Oxidase Cascade in Interspecies Competition between Streptococcus oligofermentans and Streptococcus mutans

Cited by 50 publications

References 58 publications

A Highly Arginolytic Streptococcus Species That Potently Antagonizes Streptococcus mutans

A Highly Arginolytic Streptococcus Species That Potently Antagonizes Streptococcus mutans

PerR-Regulated Manganese Ion Uptake Contributes to Oxidative Stress Defense in an Oral Streptococcus

Streptococcus mutans NADH Oxidase Lies at the Intersection of Overlapping Regulons Controlled by Oxygen and NAD + Levels

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Streptococcus mutans NADH Oxidase Lies at the Intersection of Overlapping Regulons Controlled by Oxygen and NAD ⁺ Levels