Destruction of low efficiency markers is a slow process occurring at a heteroduplex stage of transformation

Shoemaker, Nadja B.; Guild, Walter R.

doi:10.1007/bf00268516

Cited by 122 publications

(74 citation statements)

References 19 publications

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“…Bacterial Strains-The pneumococcal strains used in this study were the encapsulated serotype 2 D39 strain (18) and its unencapsulated derivative DP1004 (19). The FP228 strain, a DP1004 mutant deleted for pfbB (spr0075), has been described previously (17).…”

Section: Methodsmentioning

confidence: 99%

Plasminogen- and Fibronectin-binding Protein B Is Involved in the Adherence of Streptococcus pneumoniae to Human Epithelial Cells

Papasergi

Garibaldi

Tuscano

et al. 2010

Journal of Biological Chemistry

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Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide. The ability of this bacterium to adhere to epithelial cells is considered as an essential early step in colonization and infection. By screening a whole genome phage display library with sera from infected patients, we previously identified three antigenic fragments matching open reading frame spr0075 of the strain R6 genome. This locus encodes for an ϳ120-kDa protein, herein referred to as plasminogen-and fibronectin-binding protein B (PfbB), which displays an LPXTG cell wall anchoring motif and six repetitive domains. In this study, by using isogenic pfbB-deleted mutants of the encapsulated D39 and of the unencapsulated DP1004 type 2 pneumococcal strains, we show that PfbB is involved in S. pneumoniae adherence to various epithelial respiratory tract cell lines. Our data suggest that PfbB directly mediates bacterial adhesion, because fluorescent beads coated with the recombinant PfbB sp17 fragment (encompassing one of the six repetitive domains and the C-terminal region) efficiently bound to epithelial cells. Mutants lacking PfbB bound to fibronectin and plasminogen considerably less efficiently than wild type bacteria, whereas sp17-coated beads specifically bound to both of these substrates. Taken together, our data suggest that, by directly interacting with fibronectin, PfbB significantly increases the ability of S. pneumoniae to adhere to human epithelial cells.

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Section: Methodsmentioning

confidence: 99%

Plasminogen- and Fibronectin-binding Protein B Is Involved in the Adherence of Streptococcus pneumoniae to Human Epithelial Cells

Papasergi

Garibaldi

Tuscano

et al. 2010

Journal of Biological Chemistry

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“…S. pneumoniae Rxl (43,56), D39 (2,43), WU2 (9,14), A66 (2,8), DBL5 (66), EF3296 (8), BG9163 (8), WG44.1 (46,67), and JY2008 (67) have been previously described. JY180 is a PspA-negative derivative of strain D39 obtained by transformation with DNA from WG44.1 and selection for the erythromycin resistance marker located inpspA (this study; 67).…”

Section: Materuils and Methodsmentioning

confidence: 99%

Novel surface attachment mechanism of the Streptococcus pneumoniae protein PspA

1994

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Pneumococcal surface protein A (PspA) of Streptococcus pneumoniae has been found to utilize a novel mechanism for anchoring to the bacterial cell surface. In contrast to that of surface proteins from other gram-positive bacteria, PspA anchoring required choline-mediated interactions between the membrane-associated lipoteichoic acid and the C-terminal repeat region of PspA. Release of PspA from the cell surface could be effected by deletion of 5 of the 10 C-terminal repeat units, by high concentrations of choline, or by growth in choline-deficient medium. Other pneumococcal proteins, including autolysin, which has a similar C-terminal repeat region, were not released by these treatments. The attachment mechanism utilized by PspA thus appears to be uniquely adapted to exploit the unusual structure of the pneumococcal cell surface. Further, it has provided the means for rapid and simple isolation of immunogenic PspA from S. pneumoniae.

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“…In those studies, the donor DNA was prepared from the type 3 encapsulated strain A66. A66 was obtained from H. P. Bernheimer, and Rx1 was obtained from W. R. Guild (21). The responses to synthetic Rx1 pheromone peptide (TANA Labs, Houston, Tex.)…”

mentioning

confidence: 99%

Competence for genetic transformation in encapsulated strains of Streptococcus pneumoniae: two allelic variants of the peptide pheromone

et al. 1996

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The nucleotide sequence of comC, the gene encoding the 17-residue competence-stimulating peptide (CSP) of Streptococcus pneumoniae (L. S. Håvarstein, G. Coomaraswamy, and D. A. Morrison, Proc. Natl. Acad. Sci. USA 92:11140-11144, 1995) was determined with 42 encapsulated strains of different serotypes. A new allele, comC2, was found in 13 strains, including the type 3 Avery strain, A66, while all others carried a gene (now termed comC1) identical to that originally described for strain Rx1. The predicted mature product of comC2 is also a heptadecapeptide but differs from that of comC1 at eight residues. Both CSP-1 and CSP-2 synthetic peptides were used to induce competence in the 42 strains; 48% of the strains became competent after the addition of the synthetic peptide, whereas none were transformable without the added peptides.Genetic transformation not only is a valuable tool for molecular genetic analysis of Streptococcus pneumoniae (pneumococcus) but also appears to play a significant role in the evolution of this species, as in the assembly of mosaic antibiotic resistance genes containing blocks of information from other bacteria (6, 17) and in mediating a rapid mixing of alleles among natural populations (4). Yet, although transformation has long been described as a characteristic of the pneumococci, as a practical matter most studies involving this process have focused on a few laboratory strains, mainly descended from a single unencapsulated subclone (R36A) (2), for which optimal media and protocols were developed. Indeed, it has never been established just what proportion of pneumococcal isolates is transformable. This fraction has been difficult to assess, both because the pneumococcal capsule reduces or abolishes competence for genetic transformation (3,5,7,14,20,25) and because the optimal conditions for competence vary between strains.Competence for transformation in pneumococcus is not constitutive but is regulated by a quorum-sensing pheromone signal (23, 24). It was previously shown that culture supernatants from one strain, Rx1 (16), activate some other strains to competence and can induce competence in some encapsulated strains but not in others, including the type 3 strain A66 (25), even though an unencapsulated derivative of that strain is transformable (22). Following the recent identification of a small peptide from strain Rx1 with competence-stimulating activity (a competence-stimulating peptide [CSP]) (12), we reinvestigated the paradoxical behavior of A66, as a pure pheromone might be more effective than the crude culture supernatants used previously, but the results were still negative. We now trace the unresponsive character of strain A66 to the competence pheromone regulatory circuit itself and show that it reflects allelic variation of the pheromone gene in different isolates of this species.Failure of A66 to respond to the CSP of Rx1. Strain Rx1 is descended from R36A, an unencapsulated transformable derivative of D39S, a type 2 clinical isolate that was employed in early studies o...

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Destruction of low efficiency markers is a slow process occurring at a heteroduplex stage of transformation

Cited by 122 publications

References 19 publications

Plasminogen- and Fibronectin-binding Protein B Is Involved in the Adherence of Streptococcus pneumoniae to Human Epithelial Cells

Plasminogen- and Fibronectin-binding Protein B Is Involved in the Adherence of Streptococcus pneumoniae to Human Epithelial Cells

Novel surface attachment mechanism of the Streptococcus pneumoniae protein PspA

Competence for genetic transformation in encapsulated strains of Streptococcus pneumoniae: two allelic variants of the peptide pheromone

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