Polymorphism and regulation of the <i>spxB</i> (pyruvate oxidase) virulence factor gene by a CBS‐HotDog domain protein (SpxR) in serotype 2 <i>Streptococcus pneumoniae</i>

Ramos‐Montañez, Smirla; Tsui, Ho‐Ching Tiffany; Wayne, Kyle J.; Morris, James B.; Peters, Lindsey E.; Zhang, Faming; Kazmierczak, Krystyna M.; Sham, Lok‐To; Winkler, Malcolm E.

doi:10.1111/j.1365-2958.2007.06082.x

Cited by 95 publications

(174 citation statements)

References 77 publications

Supporting

Mentioning

163

Contrasting

Unclassified

Order By: Relevance

“…mreCD ϩ transcripts were expressed under the control of the fucose-inducible P fcsK promoter from the ectopic ⌬bgaAЈ locus (6,52). Quantitative RT-PCR and Western blotting confirmed that mreCD ϩ transcript and MreC protein were overexpressed by Ϸ5-fold or underexpressed by Ϸ2-fold from the ectopic site in the pres- The mapped P pcsB promoter, which is regulated by the WalRK Spn (VicRK) two-component regulatory system (44,50) and putative factor-independent transcription terminators (lollipops), are indicated. The bars indicate positions of probes used in Northern blots.…”

Section: Resultsmentioning

confidence: 99%

The Requirement for Pneumococcal MreC and MreD Is Relieved by Inactivation of the Gene Encoding PBP1a

2011

Self Cite

View full text Add to dashboard Cite

Three basic patterns of peptidoglycan (PG) synthesis have emerged from the study of rod-shaped (bacillus), spherical (coccus), and ellipsoid (ovococcus) bacteria (reviewed in references 12, 71, and 72). In rod-shaped bacteria, like Escherichia coli, Bacillus subtilis, and Caulobacter crescentus, PG synthesis occurs at two locations catalyzed by distinct sets of proteins (12,35,36,71). Lateral PG synthesis elongates the side walls of these bacteria and results in their rod shape (12,35,71). Lateral PG synthesis is mediated by actin-like MreB paralogue proteins, which form filamentous helical structures in spirals over the length of cells (12,35,66). MreB is thought to organize the MreC and MreD proteins, which in turn recruit specific penicillin-binding proteins (PBPs) and other division proteins that catalyze lateral PG formation (26,54,55,70). Septal PG synthesis is organized by FtsZ ring formation, followed by the orderly assembly of the divisome complex, which includes a set of PBPs different from those involved in lateral PG synthesis (16,22,23). The mutational interruption of lateral or septal PG synthesis of rod-shaped bacteria generally results in the formation of spherical or elongated cells, respectively (3, 4, 9, 31). Although useful, this two-state model is obviously an oversimplification (35), and recent results reveal that MreB, MreC, MreD, and specific PBPs also form annular rings adjacent to FtsZ rings at the septa of dividing E. coli cells (67). Moreover, some PBPs and division regulators, such as PBP1 and GpsB of B. subtilis, shuttle between the lateral and septal PG synthesis machineries (9).Much less is known about the mechanisms of PG synthesis in coccus and ovococcus species. In spherical species, such as Staphylococcus aureus, only a septal PG synthesis machinery seems to be present (20,47,72), although S. aureus still encodes homologues of proteins like MreC and MreD that mediate lateral PG synthesis in rod-shaped bacteria (35). In contrast, ovococcus species, such as Streptococcus pneumoniae and Lactococcus lactis, form American football-shaped cells by a combination of peripheral sidewall and septal PG synthesis that occurs in the midcell regions of dividing cells (Fig. 1) (11,42). Ovococcus species lack an MreB homologue, and peripheral and septal PG synthesis are likely coordinated with and organized by FtsZ ring formation (64,65,72). Because two modes of PG biosynthesis are required to form ellipsoidshaped bacteria, models have been proposed for two different PG synthesis machineries (18,21,33,72). Based on the composition of the complexes in rod-shaped cells, it has been hypothesized that specific sets of homologous cell division proteins mediate peripheral (MreC, MreD, RodA, and PBP2b) and septal (FtsZ, EzrA, PBP2x, FtsW, and DivIB/FtsL/DivIC) PG synthesis in ovococcus bacteria (72). A recent study correlating the effects of mutations or antibiotic treatments to changes in cell shapes supports the idea that the PBP2x and PBP2b class B transpeptidases are associated with septal and p...

show abstract

Section: Resultsmentioning

confidence: 99%

The Requirement for Pneumococcal MreC and MreD Is Relieved by Inactivation of the Gene Encoding PBP1a

2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…In S. mutans , VicR Sm also directly represses genes involved in competence and competence-induced bacteriocin ( comCDE and nlmC ) [113], and copY [117], part of the copYAZ operon required for copper homeostasis and regulation of membrane potential, competence, and biofilm formation [129]. In S. sanguinis , VicRK Ss does not regulate gtfP , a unique gene encoding a glucosyltransferase for the synthesis of soluble glucan [90] but does regulate spxB encoding pyruvate oxidase, required for conversion of pyruvate, inorganic phosphate, and O 2 to H 2 O 2 , CO 2 , and AcP [130]. Production of H 2 O 2 by S. sanguinis inhibits the growth of the competitor species S. mutans [131].…”

Section: Vicrk Regulons Of Tcss Are Diverse and Species-specificmentioning

confidence: 99%

Two-component signal transduction systems in oral bacteria

Mattos-Graner

Duncan²

2017

Journal of Oral Microbiology

View full text Add to dashboard Cite

We present an overview of how members of the oral microbiota respond to their environment by regulating gene expression through two-component signal transduction systems (TCSs) to support conditions compatible with homeostasis in oral biofilms or drive the equilibrium toward dysbiosis in response to environmental changes. Using studies on the sub-gingival Gram-negative anaerobe Porphyromonas gingivalis and Gram-positive streptococci as examples, we focus on the molecular mechanisms involved in activation of TCS and species specificities of TCS regulons.

show abstract

“…Most mutant strains used in this study were derived from strains IU1824 and IU1945, unencapsulated derivatives of serotype 2 S. pneumoniae strain D39 (IU1690) (see Table S1 in the supplemental material). Strains containing antibiotic markers were constructed by transforming linear DNA amplicons synthesized by overlapping fusion PCR into competent pneumococcal cells as described previously (34)(35)(36). Primers used for the generation of amplicons are listed in Table S2.…”

Section: Methodsmentioning

confidence: 99%

“…For antibiotic selection, TSAII BA plates contained 250 g kanamycin ml Ϫ1 , 150 g spectinomycin ml Ϫ1 , 0.3 g erythromycin ml Ϫ1 , 250 g streptomycin ml Ϫ1 , or 2.5 g chloramphenicol ml Ϫ1 . In most experiments, strains were cultured statically in Becton-Dickinson brain heart infusion (BHI) broth at 37°C in an atmosphere of 5% CO 2 , and growth was monitored by the optical density at 620 nm (OD 620 ) as described previously (34)(35)(36). Where indicated, bacteria were grown in a chemically defined medium (CDM) containing 1.0% (wt/vol) glucose or 1.0% (wt/ vol) galactose as the carbon source (44).…”

Section: Methodsmentioning

confidence: 99%

Minimal Peptidoglycan (PG) Turnover in Wild-Type and PG Hydrolase and Cell Division Mutants of Streptococcus pneumoniae D39 Growing Planktonically and in Host-Relevant Biofilms

et al. 2015

Self Cite

View full text Add to dashboard Cite

We determined whether there is turnover of the peptidoglycan (PG) cell wall of the ovococcus bacterial pathogen Streptococcus pneumoniae (pneumococcus). Pulse-chase experiments on serotype 2 strain D39 radiolabeled with N-acetylglucosamine revealed little turnover and release of PG breakdown products during growth compared to published reports of PG turnover in Bacillus subtilis. PG dynamics were visualized directly by long-pulse-chase-new-labeling experiments using two colors of fluorescent D-amino acid (FDAA) probes to microscopically detect regions of new PG synthesis. Consistent with minimal PG turnover, hemispherical regions of stable "old" PG persisted in D39 and TIGR4 (serotype 4) cells grown in rich brain heart infusion broth, in D39 cells grown in chemically defined medium containing glucose or galactose as the carbon source, and in D39 cells grown as biofilms on a layer of fixed human epithelial cells. In contrast, B. subtilis exhibited rapid sidewall PG turnover in similar FDAA-labeling experiments. High-performance liquid chromatography (HPLC) analysis of biochemically released peptides from S. pneumoniae PG validated that FDAAs incorporated at low levels into pentamer PG peptides and did not change the overall composition of PG peptides. PG dynamics were also visualized in mutants lacking PG hydrolases that mediate PG remodeling, cell separation, or autolysis and in cells lacking the MapZ and DivIVA division regulators. In all cases, hemispheres of stable old PG were maintained. In PG hydrolase mutants exhibiting aberrant division plane placement, FDAA labeling revealed patches of inert PG at turns and bulge points. We conclude that growing S. pneumoniae cells exhibit minimal PG turnover compared to the PG turnover in rod-shaped cells. IMPORTANCEPG cell walls are unique to eubacteria, and many bacterial species turn over and recycle their PG during growth, stress, colonization, and virulence. Consequently, PG breakdown products serve as signals for bacteria to induce antibiotic resistance and as activators of innate immune responses. S. pneumoniae is a commensal bacterium that colonizes the human nasopharynx and opportunistically causes serious respiratory and invasive diseases. The results presented here demonstrate a distinct demarcation between regions of old PG and regions of new PG synthesis and minimal turnover of PG in S. pneumoniae cells growing in culture or in host-relevant biofilms. These findings suggest that S. pneumoniae minimizes the release of PG breakdown products by turnover, which may contribute to evasion of the innate immune system. P eptidoglycan (PG) biosynthesis and placement are dynamic processes that determine the shapes, sizes, chaining, and resistance to turgor of bacterial cells (1-6). In Gram-positive bacteria, PG also serves as the scaffolding for covalent attachment of surface wall teichoic acid, capsule, and sortase-attached proteins (7-9). The seminal work of Park and Uehara demonstrated that PG is rapidly turned over and the breakdown components recycled in...

show abstract

Polymorphism and regulation of the spxB (pyruvate oxidase) virulence factor gene by a CBS‐HotDog domain protein (SpxR) in serotype 2 Streptococcus pneumoniae

Cited by 95 publications

References 77 publications

The Requirement for Pneumococcal MreC and MreD Is Relieved by Inactivation of the Gene Encoding PBP1a

The Requirement for Pneumococcal MreC and MreD Is Relieved by Inactivation of the Gene Encoding PBP1a

Two-component signal transduction systems in oral bacteria

Minimal Peptidoglycan (PG) Turnover in Wild-Type and PG Hydrolase and Cell Division Mutants of Streptococcus pneumoniae D39 Growing Planktonically and in Host-Relevant Biofilms

Contact Info

Product

Resources

About