Current trends in capsular polysaccharide biosynthesis of

Garcı́a, Ernesto; Llull, Daniel; Múñoz, Rosario; Mollerach, Marta; López, Rubens

doi:10.1016/s0923-2508(00)00173-x

Cited by 56 publications

(55 citation statements)

References 27 publications

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“…cremoris NIZO B40) (Laws et al, 2001). This structural organization is highly conserved among LAB and is very similar to that observed for the operons and clusters involved in the synthesis of: (i) O-antigen lipopolysaccharides in enterobacteria, (ii) capsules (CPS) of pathogens, such as S. pneumoniae or Staphylococcus aureus and (iii) the EPS from Sinorhizobium meliloti (García et al, 2000;Glucksmann et al, 1993;Lin et al, 1994).…”

Section: Genetic Determinants and Mechanisms Of Production And Secretionsupporting

confidence: 65%

Biosynthesis, Purification and Biotechnological Use of Exopolysaccharides Produced by Lactic Acid Bacteria

Werning¹,

Notararigo²,

Nacher³

et al. 2012

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Section: Genetic Determinants and Mechanisms Of Production And Secretionsupporting

confidence: 65%

Biosynthesis, Purification and Biotechnological Use of Exopolysaccharides Produced by Lactic Acid Bacteria

Werning¹,

Notararigo²,

Nacher³

et al. 2012

Food Additive

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“…This is because the PCR primers amplify a section of the capsulation locus between cpsA and cpsB. cpsAcpsD genes are conserved, and cpsA is Ͼ90% identical in all of the gene clusters sequenced fully (11). In addition, for some serotypes there are significant sequence differences in the cpsB homologue (11).…”

Section: Discussionmentioning

confidence: 99%

Novel PCR-Restriction Fragment Length Polymorphism Method for Determining Serotypes or Serogroups of Streptococcus pneumoniae Isolates

et al. 2005

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Serotyping Streptococcus pneumoniae is a technique generally confined to reference laboratories, as purchasing pneumococcal antisera is a huge investment. Many attempts have been made to modify serological agglutination techniques to make them more accessible, and more recently developments in serotyping have focused on molecular techniques. This paper describes a PCR assay which amplifies the entire capsulation locus between dexB and aliA. Amplicons are digested to produce serotype-specific patterns. We have shown, using 81 epidemiologically unrelated strains representing 46 different serotypes, that the patterns correlate with a 90 to 100% similarity range for the same serotype or serogroup. Prospective testing of 73 isolates of unknown serotype confirmed reliable serotype attribution, and serotype profiles are reproducible on repeated testing. Once our database contains all 90 serotypes, this technique should be fully portable, cost-effective, and useful in any laboratory with sufficient molecular experience.The species Streptococcus pneumoniae possesses more than 90 serotypes defined by their polysaccharide capsule (1). Immunologically similar serotypes, such as 19F, 19A, 19B, and 19C, are grouped together in serogroups. The immune response to capsular polysaccharide is critical for recovery from infection (17), and the first effective treatment for pneumococcal infection, serum therapy, depended on identifying the infecting serotype rapidly so that type-specific horse serum could be administered (9). The capsule is the focus for the development of an effective vaccine, initially with the 23-valent polysaccharide and more recently the protein-polysaccharide conjugate preparations that are undergoing clinical evaluation and have entered clinical use (1, 35). Some reports on the implementation of the conjugate vaccine in different communities show that there is an increase in the carriage of serotypes that are not included in the vaccine (6, 7). Additionally, serotype surveillance in developing countries and special populations, such as Aboriginal Australians, suggests that vaccine serotype coverage may be lower than for the United States and Europe, from which surveillance data were considered in vaccine formulations (2, 4, 25). Thus, there is a continuing need to study the epidemiology of S. pneumoniae as defined by capsular polysaccharide in monitoring the effect of conjugate vaccines and to aide in the development of new vaccine formulations for developing countries and special populations (12,13,16).Effective serotyping depends on a full set of group-and type-specific antisera prepared by the Statens Serum Institut (14), an investment that is beyond the resources of many laboratories. Therefore, most laboratories confine typing to the serotypes and serogroups found in the 23-valent vaccine, which represent most of the invasive types found in industrialized countries (22). As prevailing serotypes change, a wider selection of sera will be required to cover common types, thus increasing the cost. In additio...

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“…This situation is encountered for incoming DNA fragments overlapping a region that is polymorphic in the chromosome of S. pneumoniae (e.g., the capsule locus, cap; see ref. 25 for a review). Homologous sequences flanking the polymorphic region on either side (i.e., dexB or aliA sequences for the cap locus) (25) can provide a homologous recombination anchor and favor the formation of InsDels in the flanking heterologous cap region.…”

Section: A D-loop Resolvase In Transformation?mentioning

confidence: 99%

“…25 for a review). Homologous sequences flanking the polymorphic region on either side (i.e., dexB or aliA sequences for the cap locus) (25) can provide a homologous recombination anchor and favor the formation of InsDels in the flanking heterologous cap region. Evidence has been obtained that two S. pneumoniae isolates can differ by up to 10% of the chromosome (26).…”

Section: A D-loop Resolvase In Transformation?mentioning

confidence: 99%

Homologous recombination at the border: Insertion-deletions and the trapping of foreign DNA in Streptococcus pneumoniae

Prudhomme

Libante

Claverys

2002

Proc. Natl. Acad. Sci. U.S.A.

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Integration of foreign DNA was observed in the Gram-positive human pathogen Streptococcus pneumoniae (pneumococcus) after transformation with DNA from a recombinant Escherichia coli bacteriophage carrying a pneumococcal insert. Segments of DNA replaced chromosomal sequences adjacent to the region homologous with the pneumococcal insert, whence the name insertion-deletion. Here we report that a pneumococcal insert was absolutely required for insertion-deletion formation, but could be as short as 153 bp; that the sizes of foreign DNA insertions (289 -2,474 bp) and concomitant chromosomal deletions (45-1,485 bp) were not obviously correlated; that novel joints clustered preferentially within segments of high GC content; and that the crossovers in 29 independent novel joints were located 1 bp from the border or within short (3-10 nt long) stretches of identity (microhomology) between resident and foreign DNA. The data are consistent with a model in which the insert serving as a homologous recombination anchor favors interaction and subsequent illegitimate recombination events at microhomologies between foreign and resident sequences. The potential of homologydirected illegitimate recombination for genome evolution was illustrated by the trapping of functional heterologous genes. G enetic transformation, which was discovered in the Grampositive Streptococcus pneumoniae (pneumococcus) (1), is believed to play a central role in the biology of this human pathogen through its contribution to genetic plasticity (see ref.2 for a review). Transformation with naked DNA allows intraspecies and interspecies gene transfer. As such exchanges involve homologous recombination, they are generally ''conservative,'' i.e., they do not result in the creation of novel sequences but simply in a redistribution of previously existing genes. However, a pre-existing gene also can be modified when the two interacting sequences are partly divergent. Homologous recombination then leads to the production of mosaic genes, as exemplified in the case of the pbp genes of S. pneumoniae that encode altered penicillin-binding proteins with decreased affinity for ␤-lactam antibiotics (see ref. 3 for a review).Besides these conservative facets of transformation, is there any potential for the creation of novel sequence combinations or genes? The observation that transformation with chimeric donor DNA is mutagenic (4) suggested that shuffling and reassembly of previously unrelated sequences could readily occur in S. pneumoniae. The chimeric DNA extracted from a recombinant Escherichia coli bacteriophage carrying a pneumococcal insert produced illegitimate recombinants at a frequency of about 0.5% that of homologous recombinants (4). Illegitimate recombinants resulted from simultaneous insertion of heterologous vector (i.e., ) sequences and deletion of chromosomal sequences adjacent to the region homologous to the insert. These illegitimate events were therefore termed insertion-deletions (InsDels). As the pneumococcal insert in the chimeric donor seemed r...

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Current trends in capsular polysaccharide biosynthesis of

Cited by 56 publications

References 27 publications

Biosynthesis, Purification and Biotechnological Use of Exopolysaccharides Produced by Lactic Acid Bacteria

Biosynthesis, Purification and Biotechnological Use of Exopolysaccharides Produced by Lactic Acid Bacteria

Novel PCR-Restriction Fragment Length Polymorphism Method for Determining Serotypes or Serogroups of Streptococcus pneumoniae Isolates

Homologous recombination at the border: Insertion-deletions and the trapping of foreign DNA in Streptococcus pneumoniae

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