Group B streptococcal opacity variants

Pincus, Seth H.; Cole, Robert L.; Wessels, Michael R.; Corwin, Melvin D.; Kamanga-Sollo, E; Hayes, Stanley F.; Cieplak, Witold; Swanson, John

doi:10.1128/jb.174.11.3739-3749.1992

Cited by 20 publications

(15 citation statements)

References 34 publications

(17 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…No differences in either chain length, encapsulation, or growth characteristics were associated with differences in pneumococcal opacity. Characteristics of the pneumococci from transparent colonies in electron micrographs in this report were not seen in variants of either group A or group B streptococci (31,37).…”

Section: Discussionmentioning

confidence: 42%

“…The biological significance of these differences in colonial morphology has not been examined. Recently, Pincus et al reported opaque variants of group B streptococci, which also grow in longer chains (31). Differences in the growth, virulence, and immune response to these opacity variants have been described, while the relationship of phenotypic variation to the pathogenesis of group B streptococcal infection remains unknown (30).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Phase variation in pneumococcal opacity: relationship between colonial morphology and nasopharyngeal colonization

et al. 1994

View full text Add to dashboard Cite

When colonies of encapsulated isolates of Streptococcus pneumoniae are viewed with oblique, transmitted light on a transparent surface, they are heterogeneous in appearance because of variation in opacity. There is spontaneous phase variation among at least three discernible phenotypes at frequencies from 10-3 to 10-6. The ability to detect differences in opacity varies according to serotype, but variation is independent of capsule expression. Electron microscopy shows no difference in chain length but suggests that autolysis occurs earlier in the growth of the transparent variant. There was no identifiable difference in membrane protein profiles of opaque and transparent variants of the same strain. In an infant rat model of nasopharyngeal carriage, there was no significant colonization by opaque variants. Efficient and stable colonization by the transparent variants was observed, suggesting a selective advantage for this phenotype in the nasopharynx. In contrast, there was no difference in the incidence of bacteremia or in the 50% lethal dose among the variants following their intraperitoneal inoculation. These results suggest that phase variation which is marked by differences in colonial morphology may provide insight into the interaction of the pneumococcus with its host.

show abstract

Section: Discussionmentioning

confidence: 42%

Section: Discussionmentioning

confidence: 99%

Phase variation in pneumococcal opacity: relationship between colonial morphology and nasopharyngeal colonization

et al. 1994

View full text Add to dashboard Cite

show abstract

“…At all inocula tested, the mice that received the mutant strain had a greatly reduced survival rate. A correlation between colony morphology and virulence was found in several pathogenic bacteria and it was suggested that interbacterial aggregation in some way echoes the interaction between bacterium and host cell (Pincus et al ., 1992). In a recent communication, Gosink and colleagues described experiments indicating that inactivation of the pneumococcal surface protein CbpE results in decreased colonization of the nasopharynx of infant rats and decreased adherence to Detroit cells at 30°C (Gosink et al ., 2000).…”

Section: Discussionmentioning

confidence: 99%

Identification of the teichoic acid phosphorylcholine esterase in Streptococcus pneumoniae

Vollmer

Tomasz²

2001

Molecular Microbiology

View full text Add to dashboard Cite

Streptococcus pneumoniae is a major human pathogen and many interactions of this bacterium with its host appear to be mediated, directly or indirectly, by components of the bacterial cell wall, specifically by the phosphorylcholine residues which serve as anchors for surface‐located choline‐binding proteins and are also recognized by components of the host response, such as the human C‐reactive protein, a class of myeloma proteins and PAF receptors. In the present study, we describe the identification of the pneumococcal pce gene encoding for a teichoic acid phosphorylcholine esterase (Pce), an enzymatic activity capable of removing phosphorylcholine residues from the cell wall teichoic acid and lipoteichoic acid. Pce carries an N‐terminal signal sequence, contains a C‐terminal choline‐binding domain with 10 homologous repeating units similar to those found in other pneumococcal surface proteins, and the catalytic (phosphorylcholine esterase) activity is localized on the N‐terminal part of the protein. The mature protein was overexpressed in Escherichia coli and purified in a one‐step procedure by choline‐affinity chromatography and the enzymatic activity was followed using the chromophoric p‐nitrophenyl‐phosphorylcholine as a model substrate. The product of the enzymatic digestion of 3H‐choline‐labelled cell walls was shown to be phosphorylcholine. Inactivation of the pce gene in S. pneumoniae strains by insertion‐duplication mutagenesis caused a unique change in colony morphology and a striking increase in virulence in the intraperitoneal mouse model. Pce may be a regulatory element involved with the interaction of S. pneumoniae with its human host.

show abstract

“…Cell growth rate has been pointed out to regulate the expression of capsular polysaccharide in GBS [26], no further activating or repressing factors are known to in£uence regulation or phase variation of capsule expression or any other phase variation in GBS, e.g. that of colony opacity [27]. The question whether cpsX gene is the target gene of CpsY and if sensing of environmental changes occurs through coinducers of CpsY, remains open for further study.…”

Section: Discussionmentioning

confidence: 99%

Identification of two genes, cpsX and cpsY, with putative regulatory function on capsule expression in group B streptococci

Koskiniemi

1998

FEMS Immunology and Medical Microbiology

View full text Add to dashboard Cite

Two divergently transcribed open reading frames: cpsX and cpsY separated by a common regulatory region was identified upstream of the cpsA^D genes involved in polysaccharide capsule biosynthesis in group B streptococci (GBS). We suggest that these genes are involved in the regulation of capsule expression in GBS, since the CpsX protein shares sequence similarities with LytR of Bacillus subtilis, an attenuator of transcription while CpsY has similarity to a wide variety of members of the LysR family of transcriptional regulators. No deletions, insertions, DNA rearrangements, or apparent differences were discovered in the postulated regulatory genes when the gene region was compared in GBS with different capsule phenotypes. Thus, other yet unidentified gene loci may control capsule phase variation in GBS. z 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

show abstract

Group B streptococcal opacity variants

Cited by 20 publications

References 34 publications

Phase variation in pneumococcal opacity: relationship between colonial morphology and nasopharyngeal colonization

Phase variation in pneumococcal opacity: relationship between colonial morphology and nasopharyngeal colonization

Identification of the teichoic acid phosphorylcholine esterase in Streptococcus pneumoniae

Identification of two genes, cpsX and cpsY, with putative regulatory function on capsule expression in group B streptococci

Contact Info

Product

Resources

About