Recent trends on the molecular biology of pneumococcal capsules, lytic enzymes, and bacteriophage

López, Rubens; Garcı́a, Ernesto

doi:10.1016/j.femsre.2004.05.002

Cited by 165 publications

(188 citation statements)

References 217 publications

(278 reference statements)

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“…Pneumococci can produce 13 to 16 different CBPs, including four cell wall hydrolases that are important for virulence: the major autolysin LytA (N-acetylmuramoyl-L-alanine amidase), a b-N-acetylglucosamidase (LytB), a b-N-acetylmuramidase (LytC; lysozyme), and a phosphorylcholine esterase. LytA has been characterized in detail, and recently the structural analysis of the CBD of LytA demonstrated that this module adopts a peculiar solenoid structure (Ló pez & García, 2004). LytB is highly expressed in the early exponential growth phase and has been shown to be important for cell separation of pneumococci.…”

Section: Biological Activities Of Unusually Cell-wallanchored Cholinementioning

confidence: 99%

Versatility of pneumococcal surface proteins

2006

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Surface-exposed proteins are key players during the infectious process of pathogenic bacteria. The cell surface of the Gram-positive human pathogen Streptococcus pneumoniae is decorated not only by typical Gram-positive surface proteins, but also by a family of proteins that recognizes the phosphorylcholine of the lipoteichoic and teichoic acids, namely the choline-binding proteins, and by non-classical surface proteins that lack a leader peptide and membrane-anchor motif. A comprehensive understanding of how microbial proteins subvert host immunity or host protein functions is a prerequisite for the development of novel therapeutic strategies to combat pneumococcal infections. This article reviews recent progress in the investigation of the versatility and sophistication of the virulence functions of surface-exposed pneumococcal proteins.

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Section: Biological Activities Of Unusually Cell-wallanchored Cholinementioning

confidence: 99%

Versatility of pneumococcal surface proteins

2006

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“…Comparison of the primary structure of the deduced amino acid sequence of the BacL 1 protein showed significant homology with the cell wall lytic enzymes found in gram-positive bacteria (Fig. 4A) (32). Of the 595 amino acid residues of the BacL 1 protein, the N-terminal 151 amino acid residues showed a high level of homology with the lysozyme encoded on Bacillus subtilis bacteriophage B103 (accession number Q37896) (37).…”

Section: Cloning Of Component L Component a And The Immunity Genesmentioning

confidence: 86%

“…The deduced amino acid sequence encoded by bacL 1 showed a high degree of homology with the cell wall lytic enzymes and murein hydrolases of lysozyme, lysine, and the muramidase of gram-positive bacteria (32). These enzymes cleave glycan strains either between the N-acetylmuramic acid and N-acetylglucosamine or at the alternative acetylglucosamine-muramic acid glycoside linkage (34).…”

Section: Discussionmentioning

confidence: 99%

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Cloning and Genetic Analyses of the Bacteriocin 41 Determinant Encoded on the Enterococcus faecalis Pheromone-Responsive Conjugative Plasmid pYI14: a Novel Bacteriocin Complemented by Two Extracellular Components (Lysin and Activator)

Tomita¹,

Kamei²,

Ike

2008

J Bacteriol

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The conjugative plasmid pYI14 (61 kbp) was isolated from Enterococcus faecalis YI714, a clinical isolate. pYI14 conferred a pheromone response on its host and encoded bacteriocin 41 (bac41). Bacteriocin 41 (Bac41) only showed activity against E. faecalis. Physical mapping of pYI14 showed that it consisted of EcoRI fragments A to P. The clone pHT1100, containing EcoRI fragments A (12.6 kbp) and H (3.5 kbp), conferred the bacteriocin activity on E. faecalis strains. Genetic analysis showed that the determinant was located in a 6.6-kbp region within the EcoRI AH fragments. Six open reading frames (ORFs) were identified in this region and designated ORF7 (bacL 1 ) ORF8 (bacL 2 ), ORF9, ORF10, ORF11 (bacA), and ORF12 (bacI). They were aligned in this order and oriented in the same direction. ORFs bacL 1 , bacL 2 , bacA, and bacI were essential for expression of the bacteriocin in E. faecalis. Extracellular complementation of bacteriocin expression was possible for bacL 1 and -L 2 and bacA mutants. bacL 1 and -L 2 and bacA encoded bacteriocin component L and activator component A, respectively. The products of these genes are secreted into the culture medium and extracellularly complement bacteriocin expression. bacI encoded immunity, providing the host with resistance to its own bacteriocin activity. The bacL 1 -encoded protein had significant homology with lytic enzymes that attack the gram-positive bacterial cell wall. Sequence data for the deduced bacL 1 -encoded protein suggested that it has a domain structure consisting of an N-terminal signal peptide, a second domain with the enzymatic activity, and a third domain with a three-repeat structure directing the proenzyme to its cell surface receptor.Bacteriocins are bacterial proteins or peptides which inhibit the growth of other bacteria that are closely related to the producer strain. They usually exhibit a relatively narrow spectrum of activity and are produced by a wide variety of grampositive and gram-negative bacteria (27). Bacteriocin production is thought to provide the host strain with an ecological or other selective advantage over other strains.Many Enterococcus faecalis clinical isolates produce a bacteriocin (3, 5), and the bacteriocin is frequently encoded on the E. faecalis pheromone-responding conjugative plasmid (6,14,21,46). Several E. faecalis bacteriocins have been genetically and biochemically characterized (15, 35), including the ␤-hemolysin/bacteriocin (cytolysin) (6,7,18,20,22) and the peptide antibiotics AS-48 (33), bacteriocin 21 (47), and bacteriocin 31 (46), which are encoded by the E. faecalis conjugative plasmids pAD1 (58 kbp), pMB2 (58 kbp), pPD1 (59 kbp), and pYI17 (57.5 kbp), respectively. A significant number of E. faecalis clinical isolates produce hemolysin/bacteriocin (10, 26), and more than 50% of the hemolytic clinical isolates carry transferable hemolysin/bacteriocin determinants (21, 26). The hemolysin/bacteriocin of pAD1 is associated with virulence in animal models (4,25,29), and this plasmid is considered to be a typical ...

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“…LytA, an N -acetylmuramyl-l-alanine amidase, is important for peptidoglycan remodeling during growth [36] and appears to be constitutively expressed [37,38]. Death or suicide of S. pneumoniae in the stationary phase has been attributed to autolysis by LytA [38,39], however, it has been proposed that spontaneous pneumococcal death is due to hydrogen peroxide (H 2 O 2 ), a by-product of aerobic metabolism by SpxB, not LytA [40]. Taken together, not only cell wall attached proteins but also exposed Ccs4 may interact with host cells when host-pneumococcal contact induces LytA expression, causing degradation of the cell wall peptidoglycan and capsule.…”

Section: Discussionmentioning

confidence: 99%

Competence-induced protein Ccs4 facilitates pneumococcal invasion into brain tissue and virulence in meningitis

et al. 2018

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Streptococcus pneumoniae is a major pathogen that causes pneumonia, sepsis, and meningitis. The candidate combox site 4 (ccs4) gene has been reported to be a pneumococcal competence-induced gene. Such genes are involved in development of S. pneumoniae competence and virulence, though the functions of ccs4 remain unknown. In the present study, the role of Ccs4 in the pathogenesis of pneumococcal meningitis was examined. We initially constructed a ccs4 deletion mutant and complement strains, then examined their association with and invasion into human brain microvascular endothelial cells. Wild-type and Ccs4-complemented strains exhibited significantly higher rates of association and invasion as compared to the ccs4 mutant strain. Deletion of ccs4 did not change bacterial growth activity or expression of NanA and CbpA, known brain endothelial pneumococcal adhesins. Next, mice were infected either intravenously or intranasally with pneumococcal strains. In the intranasal infection model, survival rates were comparable between wild-type strain-infected and ccs4 mutant strain-infected mice, while the ccs4 mutant strain exhibited a lower level of virulence in the intravenous infection model. In addition, at 24 hours after intravenous infection, the bacterial burden in blood was comparable between the wild-type and ccs4 mutant strain-infected mice, whereas the wild-type strain-infected mice showed a significantly higher bacterial burden in the brain. These results suggest that Ccs4 contributes to pneumococcal invasion of host brain tissues and functions as a virulence factor.

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Recent trends on the molecular biology of pneumococcal capsules, lytic enzymes, and bacteriophage

Cited by 165 publications

References 217 publications

Versatility of pneumococcal surface proteins

Versatility of pneumococcal surface proteins

Cloning and Genetic Analyses of the Bacteriocin 41 Determinant Encoded on the Enterococcus faecalis Pheromone-Responsive Conjugative Plasmid pYI14: a Novel Bacteriocin Complemented by Two Extracellular Components (Lysin and Activator)

Competence-induced protein Ccs4 facilitates pneumococcal invasion into brain tissue and virulence in meningitis

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