Insertional inactivation of Streptococcus pyogenes sod suggests that prtF is regulated in response to a superoxide signal

Gibson, Carmela M.; Caparon, Michael G.

doi:10.1128/jb.178.15.4688-4695.1996

Cited by 53 publications

(58 citation statements)

References 45 publications

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“…Expression of a major adhesin, the fibronectin-binding protein known as protein F or Sfb, is environmentally regulated, being preferentially expressed in aerobic environments (51). Regulation occurs at the level of transcription and is apparently linked to a pathway that senses oxidative stress (22). These observations suggest that S. pyogenes encounters and reacts to an aerobic environment during infection.…”

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confidence: 81%

“…To prepare solid medium for S. pyogenes, Bacto Agar (Difco) was added to THY medium to a final concentration of 1.4%. Various atmospheres for cultures of S. pyogenes were created using conditions established in prior investigations (22). Briefly, for aerobic cultures, streptococci were grown on solid medium in ambient air (20% O 2 , 0.03% CO 2 ) or in liquid medium in a 125-ml Erlenmeyer flask filled to 8% of its total volume on an orbital shaker rotating at 225 rpm.…”

Section: Methodsmentioning

confidence: 99%

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Aerotolerance and Peroxide Resistance in Peroxidase and PerR Mutants of Streptococcus pyogenes

2000

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Survival in aerobic conditions is critical to the pathogenicity of many bacteria. To investigate the means of aerotolerance and resistance to oxidative stress in the catalase-negative organism Streptococcus pyogenes, we used a genomics-based approach to identify and inactivate homologues of two peroxidase genes, encoding alkyl hydroperoxidase (ahpC) and glutathione peroxidase (gpoA). Single and double mutants survived as well as the wild type under aerobic conditions. However, they were more susceptible than the wild type to growth suppression by paraquat and cumene hydroperoxide. In addition, we show that S. pyogenes demonstrates an inducible peroxide resistance response when treated with sublethal doses of peroxide. This resistance response was intact in ahpC and gpoA mutants but not in mutants lacking PerR, a repressor of several genes including ahpC and catalase (katA) in Bacillus subtilis. Because our data indicate that these peroxidase genes are not essential for aerotolerance or induced resistance to peroxide stress in S. pyogenes, genes for a novel mechanism of managing peroxide stress may be regulated by PerR in streptococci.

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confidence: 81%

Section: Methodsmentioning

confidence: 99%

Aerotolerance and Peroxide Resistance in Peroxidase and PerR Mutants of Streptococcus pyogenes

2000

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“…This might be significant in promoting initial adherence of cells to the pharynx or skin (VanHeyningen et al, 1993). Superoxide stress, under 02-limited conditions, also stimulates PrtFl expression (Gibson and Caparon, 1996). Another Fn-binding activity has been recently identified which requires oxygen (or oxidants) for pH-sensitive activation of Zn2+-dependent Fn-binding.…”

Section: Streptococcal Adhesion To Extracellular Matrix Molecules Andmentioning

confidence: 99%

Streptococcal Adhesion and Colonization

Jenkinson

Lamont

1997

Critical Reviews in Oral Biology & Medicine

243

187

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Streptococci express arrays of adhesins on their cell surfaces that facilitate adherence to substrates present in their natural environment within the mammalian host. A consequence of such promiscuous binding ability is that streptococcal cells may adhere simultaneously to a spectrum of substrates, including salivary glycoproteins, extracellular matrix and serum components, host cells, and other microbial cells. The multiplicity of streptococcal adherence interactions accounts, at least in part, for their success in colonizing the oral and epithelial surfaces of humans. Adhesion facilitates colonization and may be a precursor to tissue invasion and immune modulation, events that presage the development of disease. Many of the streptococcal adhesins and virulence-related factors are cell-wall-associated proteins containing repeated sequence blocks of amino acids. Linear sequences, both within the blocks and within non-repetitive regions of the proteins, have been implicated in substrate binding. Sequences and functions of these proteins among the streptococci have become assorted through gene duplication and horizontal transfer between bacterial populations. Several adhesins identified and characterized through in vitro binding assays have been analyzed for in vivo expression and function by means of animal models used for colonization and virulence. Information on the molecular structure of adhesins as related to their in vivo function will allow for the rational design of novel acellular vaccines, recombinant antibodies, and adhesion agonists for the future control or prevention of streptococcal colonization and streptococcal diseases.

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“…From mid-log phase (A 660 of 0.2), the increase in cell mass would lead to increased production of H 2 (29), and their deduced amino acid sequences showed 75.4 and 57.1% identity, respectively, with that of S. mutans Dpr. To date, nonheme peroxidases (30, 31), a pseudocatalase (20), and oxidases (2, 10, 16, 34) of lactic acid bacteria, including streptococci, have been reported to substitute for catalase, which is present in other aerotolerant bacteria but not lactic acid bacteria, and some of them, including SOD, were proven to play a role in aerotolerance (9,10,21,27,33). Unlike them, Dpr did not directly react with oxygen and reactive oxygen species.…”

Section: Identification Of a Peroxide Resistance Gene From S Mutansmentioning

confidence: 99%

Role of the dpr Product in Oxygen Tolerance in Streptococcus mutans

et al. 2000

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We have previously identified and characterized the alkyl hydroperoxide reductase of Streptococcus mutans, which consists of two components, Nox-1 and AhpC. Deletion of both nox-1 and ahpC had no effect on the sensitivity of S. mutans to cumene hydroperoxide or H 2 O 2 , implying that the existence of another antioxidant system(s) independent of the Nox-1-AhpC system compensates for the deficiency. Here, a new antioxidant gene (dpr for Dps-like peroxide resistance gene) was isolated from the S. mutans chromosome by its ability to complement an ahpCF deletion mutant of Escherichia coli with a tert-butyl hydroperoxide-hypersensitive phenotype. The dpr gene complemented the defect in peroxidase activity caused by the deletion of nox-1 and ahpC in S. mutans. Under aerobic conditions, the dpr disruption mutant carrying a spectinomycin resistance gene (dpr::Spc r mutant) grew as well as wild-type S. mutans in liquid medium. However, the dpr::Spc r mutant could not form colonies on an agar plate under air. In addition, neither the dpr::Spc r ahpC::Em r ::nox-1 triple mutant nor the dpr::Spc r sod::Em r double mutant was able to grow aerobically in liquid medium. The 20-kDa dpr gene product Dpr is an iron-binding protein. Synthesis of Dpr was induced by exposure of S. mutans cells to air. We propose a mechanism by which Dpr confers aerotolerance on S. mutans.Bacteria contain certain enzymes capable of reacting with oxygen, and they cannot avoid confronting harmful reactive oxygen species, including superoxide anion (O 2 Ϫ ), hydrogen peroxide (H 2 O 2 ), and organic hydroperoxide, if they are exposed to air. To live in the presence of oxygen, they have to convert these reactive oxygen species to nontoxic molecules. Therefore, enzymes such as superoxide dismutases (SOD), catalases, and peroxidases are ubiquitously distributed in aerotolerant bacteria.Lactic acid bacteria, including Streptococcus mutans, lack cytochromes and other heme-containing proteins. Most lactic acid bacteria, except several lactobacilli which acquire catalase activity if a source of heme is added to their growth medium (42), also lack catalase. However, they can grow in the presence of air. In view of the defense against oxygen toxicity, the lack of catalase in lactic acid bacteria is inconsistent with their aerotolerance. Mechanisms by which lactic acid bacteria cope with peroxide-mediated stress are therefore an area under active investigation. We previously identified H 2 O 2 -forming NADH oxidase (Nox-1) in S. mutans and found that Nox-1 is homologous with a flavoprotein component, AhpF, of Salmonella typhimurium alkyl hydroperoxide reductase (AhpR), consisting of AhpF and AhpC (16,17,30). We also identified ahpC, which is homologous with ahpC of S. typhimurium, upstream of nox-1 in S. mutans (30). Analyses of purified AhpC together with Nox-1 have verified that these proteins act as a bicomponent peroxidase system in S. mutans, catalyzing the NADH-dependent reduction of organic hydroperoxides or H 2 O 2 to their respective alcohols and/or H 2 ...

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Insertional inactivation of Streptococcus pyogenes sod suggests that prtF is regulated in response to a superoxide signal

Cited by 53 publications

References 45 publications

Aerotolerance and Peroxide Resistance in Peroxidase and PerR Mutants of Streptococcus pyogenes

Aerotolerance and Peroxide Resistance in Peroxidase and PerR Mutants of Streptococcus pyogenes

Streptococcal Adhesion and Colonization

Role of the dpr Product in Oxygen Tolerance in Streptococcus mutans

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