scholarly journals Genetic Basis for the Structural Difference between Streptococcus pneumoniae Serotype 15B and 15C Capsular Polysaccharides

2003 ◽  
Vol 71 (11) ◽  
pp. 6192-6198 ◽  
Author(s):  
Saskia van Selm ◽  
Lisette M. van Cann ◽  
Marc A. B. Kolkman ◽  
Bernard A. M. van der Zeijst ◽  
Jos P. M. van Putten
Keyword(s):  
Streptococcus Pneumoniae ◽  
Genetic Analysis ◽  
Genetic Basis ◽  
Capsular Polysaccharide ◽  
Structural Difference ◽  
Open Reading Frames ◽  
Structural Level ◽  
Reading Frame ◽  
Polysaccharide Synthesis ◽  
Short Tandem

ABSTRACT In a search for the genetic basis for the structural difference between the related Streptococcus pneumoniae capsular serotypes 15B and 15C and for the reported reversible switching between these serotypes, the corresponding capsular polysaccharide synthesis (cps) loci were investigated by keeping in mind that at the structural level, the capsules differ only in O acetylation. The cps locus of a serotype 15B strain was identified, partially PCR amplified with primers based on the related serotype 14 sequence, and sequenced. Sequence analysis revealed, among other open reading frames, an intact open reading frame (designated cps15bM) whose product, at the protein level, exhibited characteristics of previously identified acetyltransferases. Genetic analysis of the corresponding region in a serotype15C strain indicated that the same gene was present but had a premature stop in translation. Closer analysis indicated that the serotype 15B gene contained a short tandem TA repeat consisting of eight TA units. In serotype 15C, this gene contained nine TA units that resulted in a frameshift and a truncated product. Genetic analysis of 17 serotype 15B and 15C clinical isolates revealed a perfect correlation between the serotype and the length of the short tandem repeat in the putative O-acetyltransferase gene. The number of TA repeating units varied between seven and nine in the various isolates. Together, the data strongly suggest that the structural difference between serotypes 15B and 15C is based on variation in the short tandem TA repeat in the O-acetyltransferase gene and that the transition between serotypes is due to slipped-strand mispairing with deletion or insertion of TA units in the cps15bM gene.

scholarly journals Comparative Genetics of Capsular Polysaccharide Biosynthesis in Streptococcus pneumoniae Types Belonging to Serogroup 19

1999 ◽  
Vol 181 (17) ◽  
pp. 5355-5364 ◽  
Author(s):  
Judy K. Morona ◽  
Renato Morona ◽  
James C. Paton
Keyword(s):  
Streptococcus Pneumoniae ◽  
Genetic Basis ◽  
Capsular Polysaccharide ◽  
Single Gene ◽  
Repeat Unit ◽  
Structural Difference ◽  
Structural Diversity ◽  
Polysaccharide Biosynthesis ◽  
Flanking Sequences ◽  
The Individual

ABSTRACT The genetic basis for the structural diversity of capsule polysaccharide (CPS) in Streptococcus pneumoniae serogroup 19 (consisting of types 19F, 19A, 19B, and 19C) has been determined for the first time. In this study, the genetic basis for the 19A and 19C serotypes is described, and the structures of all four serogroup 19cps loci and their flanking sequences are compared. Transformation studies show that the structural difference between the 19A and 19F CPSs is likely to be a consequence of differences between their respective polysaccharide polymerase genes (cps19aIand cps19fI). The CPS of type 19C differs from that of type 19B by the addition of glucose. We have identified a single gene difference between the two cps loci (cps19cS), which is likely to encode a glucosyl transferase. The arrangement of the genes within the cps19 loci is highly conserved, with 13 genes (cps19A to -H and cps19Kto -O) common to all four serogroup 19 members. Thesecps genes encode functions required for the synthesis of the shared trisaccharide component of the group 19 CPS repeat unit structures. Furthermore, the genetic differences between the group 19cps loci identified are consistent with the CPS structures of the individual serotypes. Functions have been assigned to nearly all of the cps19 gene products, based on either gene complementation or similarity to other proteins with known functions, and putative biosynthetic pathways for production of all four group 19 CPSs have been proposed.

scholarly journals Genetic analysis of the capsular polysaccharide synthesis locus in 15 Streptococcus suis serotypes

2011 ◽  
Vol 324 (2) ◽  
pp. 117-124 ◽  
Author(s):  
Kaicheng Wang ◽  
Weixing Fan ◽  
Lijuan Cai ◽  
Baoxu Huang ◽  
Chengping Lu
Keyword(s):  
Genetic Analysis ◽  
Capsular Polysaccharide ◽  
Streptococcus Suis ◽  
Polysaccharide Synthesis

scholarly journals Genetic analysis of capsular polysaccharide synthesis gene clusters in 79 capsular types of Klebsiella spp

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Yi-Jiun Pan ◽  
Tzu-Lung Lin ◽  
Chun-Tang Chen ◽  
Yi-Yin Chen ◽  
Pei-Fang Hsieh ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Capsular Polysaccharide ◽  
Gene Clusters ◽  
Polysaccharide Synthesis ◽  
Klebsiella Spp

scholarly journals THE GENETIC BASIS FOR MUCOIDY AND RADIATION SENSITIVITY IN capR (lon) MUTANTS OF E. coli K-12

Genetics ◽  
1973 ◽  
Vol 74 (2) ◽  
pp. 215-225
Author(s):  
John W Bush ◽  
Alvin Markovitz
Keyword(s):  
Genetic Basis ◽  
Capsular Polysaccharide ◽  
Radiation Sensitivity ◽  
Polar Effect ◽  
Pleiotropic Effects ◽  
E Coli ◽  
Polysaccharide Synthesis ◽  
K 12 ◽  
Nonsense Suppressors

ABSTRACT CapR mutants of E. coli K-12 overproduce capsular polysaccharide (mucoid phenotype) and enzymes involved in capsular polysaccharide synthesis, and they are sensitive to radiation. It has been uncertain whether both properties are mediated by damage to a single cistron or by a polar effect on a second cistron in the same operon. Introduction of a polarity suppressor caused no change in the overproduction of polysaccharide, in the enzymes of polysaccharide synthesis or in radiation sensitivity of the capR mutant. Thus mucoidy and radiation sensitivity resulting from capR (lon) mutations are both the consequences of impairment of the same cistron. The experiments demonstrate the advantage of the use of polarity suppressors (over conventional nonsense suppressors) in determining whether pleiotropic effects of a mutation are the result of polarity.

scholarly journals Characterization of the Type 8 Capsular Gene Cluster of Streptococcus pneumoniae

1999 ◽  
Vol 181 (19) ◽  
pp. 6214-6219 ◽  
Author(s):  
Rosario Muñoz ◽  
Marta Mollerach ◽  
Rubens López ◽  
Ernesto García
Keyword(s):  
Streptococcus Pneumoniae ◽  
Nucleotide Sequence ◽  
Gene Cluster ◽  
Complete Nucleotide Sequence ◽  
Capsular Polysaccharide ◽  
Open Reading Frames ◽  
Dna Fragment ◽  
Type 3 ◽  
Reading Frames

ABSTRACT The complete nucleotide sequence of the capsular gene cluster (cap8) responsible for the biosynthesis of the capsular polysaccharide of Streptococcus pneumoniae type 8 has been determined. The cap8 gene cluster, located between the genes dexB and aliA, is composed of 12 open reading frames. A 14.7-kb DNA fragment embracing the cap8genes was sufficient to transform an unencapsulated type 3 S. pneumoniae strain to a strain with the type 8 capsule. A possible scenario for the evolution of pneumococcal types 2 and 8 is outlined.

scholarly journals Molecular Characterization of the Complete 23F Capsular Polysaccharide Locus of Streptococcus pneumoniae

1998 ◽  
Vol 180 (19) ◽  
pp. 5273-5278 ◽  
Author(s):  
Mario Ramirez ◽  
Alexander Tomasz
Keyword(s):  
Streptococcus Pneumoniae ◽  
Molecular Characterization ◽  
Dna Sequence ◽  
Capsular Polysaccharide ◽  
Open Reading Frames ◽  
The Other ◽  
Reading Frames

ABSTRACT The complete DNA sequence of the capsular locus 23F ofStreptococcus pneumoniae is presented. The 18.6-kbcps23f locus is composed of 18 open reading frames flanked at the 5′ and 3′ ends by the genes dexB andaliA, an arrangement similar to those of some of the other identified cps loci.

scholarly journals Construction of Otherwise Isogenic Serotype 6B, 7F, 14, and 19F Capsular Variants of Streptococcus pneumoniae Strain TIGR4

2003 ◽  
Vol 69 (12) ◽  
pp. 7364-7370 ◽  
Author(s):  
Krzysztof Trzcinski ◽  
Claudette M. Thompson ◽  
Marc Lipsitch
Keyword(s):  
Streptococcus Pneumoniae ◽  
Capsular Polysaccharide ◽  
Rflp Analysis ◽  
Capsular Type ◽  
Chromosomal Dna ◽  
Subsequent Transformation ◽  
Polysaccharide Synthesis ◽  
Quellung Reaction ◽  
Flanking Regions

ABSTRACT The polysaccharide capsule is the primary virulence factor in Streptococcus pneumoniae. There are at least 90 serotypes of S. pneumoniae, identified based on the immunogenicity of different capsular sugars. The aim of this study was to construct pneumococcal strains that are isogenic except for capsular type. Serotype 4 strain TIGR4 was rendered unencapsulated by recombinational replacement of the capsular polysaccharide synthesis (cps) locus with the bicistronic Janus cassette (C. K. Sung, J. P. Claverys, and D. A. Morrison, Appl. Environ. Microbiol. 67:5190-5196, 2001). In subsequent transformation with chromosomal DNA, the cassette was replaced by the cps locus derived from a strain of a different serotype, either 6B, 7F, 14, or 19F. To minimize the risk of uncontrolled recombinational replacements in loci other than cps, the TIGRcps::Janus strain was“ backcross” transformed three times with chromosomal DNA of subsequently constructed capsular type transformants. Capsular serotypes were confirmed in all new capsule variants by the Quellung reaction. Restriction fragment length polymorphism (RFLP) analysis of the cps locus confirmed the integrity of the cps region transformed into the TIGR strain, and RFLP of the flanking regions confirmed their identities with the corresponding regions of the recipient. Transformants had in vitro growth rates greater than or equal to that of TIGR4. All four strains were able to colonize C57BL/6 mice (female, 6 weeks old) for at least 7 days when mice were intranasally inoculated with 6 × 106 to 8 × 106 CFU. The constructed capsular variants of TIGR4 are suitable for use in studies on the role of S. pneumoniae capsular polysaccharide in immunity, colonization, and pathogenesis.

scholarly journals SPD_1495 Contributes to Capsular Polysaccharide Synthesis and Virulence in Streptococcus pneumoniae

mSystems ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Yun-Dan Zheng ◽  
Ying Pan ◽  
Ke He ◽  
Nan Li ◽  
Donghong Yang ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Capsular Polysaccharide ◽  
Deep Understanding ◽  
Bacterial Virulence ◽  
Mobility Shift ◽  
Synthesis Mechanism ◽  
Content Type ◽  
Polysaccharide Synthesis ◽  
Key Factor ◽  
Mobility Shift Assay

ABSTRACT Streptococcus pneumoniae, a Gram-positive human pathogen, causes a series of serious diseases in humans. SPD_1495 from S. pneumoniae is annotated as a hypothetical ABC sugar-binding protein in the NCBI database, but there are few reports on detailed biological functions of SPD_1495. To fully study the influence of SPD_1495 on bacterial virulence in S. pneumoniae, we constructed a deletion mutant (D39Δspd1495) and an overexpressing strain (D39spd1495+). Comparative analysis of iTRAQ-based quantitative proteomic data of the wild-type D39 strain (D39-WT) and D39Δspd1495 showed that several differentially expressed proteins that participate in capsular polysaccharide synthesis, such as Cps2M, Cps2C, Cps2L, Cps2T, Cps2E, and Cps2D, were markedly upregulated in D39Δspd1495. Subsequent transmission electron microscopy and uronic acid detection assay confirmed that capsular polysaccharide synthesis was enhanced in D39Δspd1495 compared to that in D39-WT. Moreover, knockout of spd1495 resulted in increased capsular polysaccharide synthesis, as well as increased bacterial virulence, as confirmed by the animal study. Through a coimmunoprecipitation assay, surface plasmon resonance, and electrophoretic mobility shift assay, we found that SPD_1495 negatively regulated cps promoter expression by interacting with phosphorylated ComE, a negative transcriptional regulator for capsular polysaccharide formation. Overall, this study suggested that SPD_1495 negatively regulates capsular polysaccharide formation and thereby enhances bacterial virulence in the host. These findings also provide valuable insights into understanding the biology of this clinically important bacterium. IMPORTANCE Capsular polysaccharide is a key factor underlying the virulence of Streptococcus pneumoniae in human diseases. Thus, a deep understanding of capsular polysaccharide synthesis is essential for uncovering the pathogenesis of S. pneumoniae infection. In this study, we show that protein SPD_1495 interacts with phosphorylated ComE to negatively regulate the formation of capsular polysaccharide. Deletion of spd1495 increased capsular polysaccharide synthesis and thereby enhanced bacterial virulence. These findings further reveal the synthesis mechanism of capsular polysaccharide and provide new insight into the biology of this clinically important bacterium.

Sign in / Sign up

Export Citation Format

Share Document