1
|
Current challenges in the accurate identification of Streptococcus pneumoniae and its serogroups/serotypes in the vaccine era. J Microbiol Methods 2017; 141:48-54. [DOI: 10.1016/j.mimet.2017.07.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 07/30/2017] [Accepted: 07/31/2017] [Indexed: 11/21/2022]
|
2
|
Identification of proteins in Streptococcus pneumoniae by reverse vaccinology and genetic diversity of these proteins in clinical isolates. Appl Biochem Biotechnol 2014; 175:2124-65. [PMID: 25448632 DOI: 10.1007/s12010-014-1375-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
Abstract
Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide. Virulence-associated proteins common and conserved among all capsular types now represent the best strategy to combat pneumococcal infections. Our aim was to identify conserved targets in pneumococci that showed positive prediction for lipoprotein and extracellular subcellular location using bioinformatics programs and verify the distribution and the degree of conservation of these targets in pneumococci. These targets can be considered potential vaccine candidate to be evaluated in the future. A set of 13 targets were analyzed and confirmed the presence in all pneumococci tested. These 13 genes were highly conserved showing around >96 % of amino acid and nucleotide identity, but they were also present and show high identity in the closely related species Streptococcus mitis, Streptococcus oralis, and Streptococcus pseudopneumoniae. S. oralis clusters away from S. pneumoniae, while S. pseudopneumoniae and S. mitis cluster closer. The divergence between the selected targets was too small to be observed consistently in phylogenetic groups between the analyzed genomes of S. pneumoniae. The proteins analyzed fulfill two of the initial criteria of a vaccine candidate: targets are present in a variety of different pneumococci strains including different serotypes and are conserved among the samples evaluated.
Collapse
|
3
|
Tavares DA, Simões AS, Bootsma HJ, Hermans PWM, de Lencastre H, Sá-Leão R. Non-typeable pneumococci circulating in Portugal are of cps type NCC2 and have genomic features typical of encapsulated isolates. BMC Genomics 2014; 15:863. [PMID: 25283442 PMCID: PMC4200197 DOI: 10.1186/1471-2164-15-863] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 09/29/2014] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Pneumococcus is a major human pathogen and the polysaccharide capsule is considered its main virulence factor. Nevertheless, strains lacking a capsule, named non-typeable pneumococcus (NT), are maintained in nature and frequently colonise the human nasopharynx. Interest in these strains, not targeted by any of the currently available pneumococcal vaccines, has been rising as they seem to play an important role in the evolution of the species. Currently, there is a paucity of data regarding this group of pneumococci. Also, questions have been raised on whether they are true pneumococci. We aimed to obtain insights in the genetic content of NT and the mechanisms leading to non-typeability and to genetic diversity. RESULTS A collection of 52 NT isolates representative of the lineages circulating in Portugal between 1997 and 2007, as determined by pulsed-field gel electrophoresis and multilocus sequence typing, was analysed. The capsular region was sequenced and comparative genomic hybridisation (CGH) using a microarray covering the genome of 10 pneumococcal strains was carried out. The presence of mobile elements was investigated as source of intraclonal variation. NT circulating in Portugal were found to have similar capsular regions, of cps type NCC2, i.e., having aliB-like ORF1 and aliB-like ORF2 genes. The core genome of NT was essentially similar to that of encapsulated strains. Also, competence genes and most virulence genes were present. The few virulence genes absent in all NT were the capsular genes, type-I and type-II pili, choline-binding protein A (cbpA/pspC), and pneumococcal surface protein A (pspA). Intraclonal variation could not be entirely explained by the presence of prophages and other mobile elements. CONCLUSIONS NT circulating in Portugal are a homogeneous group belonging to cps type NCC2. Our observations support the theory that they are bona-fide pneumococcal isolates that do not express the capsule but are otherwise essentially similar to encapsulated pneumococci. Thus we propose that NT should be routinely identified and reported in surveillance studies.
Collapse
Affiliation(s)
- Débora A Tavares
- />Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica (ITQB) António Xavier, Universidade Nova de Lisboa (UNL), Oeiras, Portugal
| | - Alexandra S Simões
- />Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica (ITQB) António Xavier, Universidade Nova de Lisboa (UNL), Oeiras, Portugal
| | - Hester J Bootsma
- />Laboratory of Paediatric Infectious Diseases, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Peter WM Hermans
- />Laboratory of Paediatric Infectious Diseases, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
- />Crucell – Johnson and Johnson, Leiden, the Netherlands
| | - Hermínia de Lencastre
- />Laboratory of Molecular Genetics, ITQB, UNL, Oeiras, Portugal
- />Laboratory of Microbiology and Infectious Diseases, The Rockefeller University, New York, NY USA
| | - Raquel Sá-Leão
- />Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica (ITQB) António Xavier, Universidade Nova de Lisboa (UNL), Oeiras, Portugal
| |
Collapse
|
4
|
Lara B, Rico AI, Petruzzelli S, Santona A, Dumas J, Biton J, Vicente M, Mingorance J, Massidda O. Cell division in cocci: localization and properties of the Streptococcus pneumoniae FtsA protein. Mol Microbiol 2005; 55:699-711. [PMID: 15660997 DOI: 10.1111/j.1365-2958.2004.04432.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We studied the cytological and biochemical properties of the FtsA protein of Streptococcus pneumoniae. FtsA is a widespread bacterial cell division protein that belongs to the actin superfamily. In Escherichia coli and Bacillus subtilis, FtsA localizes to the septal ring after FtsZ, but its exact role in septation is not known. In S. pneumoniae, we found that, during exponential growth, the protein localizes to the nascent septa, at the equatorial zones of the dividing cells, where an average of 2200 FtsA molecules per cell are present. Likewise, FtsZ was found to localize with the same pattern and to be present at an average of 3000 molecules per cell. Consistent with the colocalization, FtsA was found to interact with FtsZ and with itself. Purified FtsA is able to bind several nucleotides, the affinity being highest for adenosine triphosphate (ATP), and lower for other triphosphates and diphosphates. The protein polymerizes in vitro, in a nucleotide-dependent manner, forming long corkscrew-like helixes, composed of 2 + 2 paired protofilaments. No nucleotide hydrolytic activity was detected. Consistent with the absence of an ATPase activity, the polymers are highly stable and not dynamic. These results suggest that the FtsA protein could also polymerize in vivo and the polymers participate in septation.
Collapse
Affiliation(s)
- Beatriz Lara
- Aventis Pharma, 102 Route de Noisy, F-93235 Romainville cedex, France
| | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Neuhaus FC, Baddiley J. A continuum of anionic charge: structures and functions of D-alanyl-teichoic acids in gram-positive bacteria. Microbiol Mol Biol Rev 2003; 67:686-723. [PMID: 14665680 PMCID: PMC309049 DOI: 10.1128/mmbr.67.4.686-723.2003] [Citation(s) in RCA: 722] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Teichoic acids (TAs) are major wall and membrane components of most gram-positive bacteria. With few exceptions, they are polymers of glycerol-phosphate or ribitol-phosphate to which are attached glycosyl and D-alanyl ester residues. Wall TA is attached to peptidoglycan via a linkage unit, whereas lipoteichoic acid is attached to glycolipid intercalated in the membrane. Together with peptidoglycan, these polymers make up a polyanionic matrix that functions in (i) cation homeostasis; (ii) trafficking of ions, nutrients, proteins, and antibiotics; (iii) regulation of autolysins; and (iv) presentation of envelope proteins. The esterification of TAs with D-alanyl esters provides a means of modulating the net anionic charge, determining the cationic binding capacity, and displaying cations in the wall. This review addresses the structures and functions of D-alanyl-TAs, the D-alanylation system encoded by the dlt operon, and the roles of TAs in cell growth. The importance of dlt in the physiology of many organisms is illustrated by the variety of mutant phenotypes. In addition, advances in our understanding of D-alanyl ester function in virulence and host-mediated responses have been made possible through targeted mutagenesis of dlt. Studies of the mechanism of D-alanylation have identified two potential targets of antibacterial action and provided possible screening reactions for designing novel agents targeted to D-alanyl-TA synthesis.
Collapse
Affiliation(s)
- Francis C Neuhaus
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208. USA.
| | | |
Collapse
|
6
|
Abstract
OBJECTIVES To review the advances in clinically useful molecular biological techniques and to identify their applications in clinical practice, as presented at the Tenth Annual William Beaumont Hospital DNA Symposium. DATA SOURCES The 11 manuscripts submitted were reviewed and their major findings were compared with literature on the same topic. STUDY SELECTION Manuscripts address creative thinking techniques applied to DNA discovery, extraction of DNA from clotted blood, the relationship of mitochondrial dysfunction in neurodegenerative disorders, and molecular methods to identify human lymphocyte antigen class I and class II loci. Two other manuscripts review current issues in molecular microbiology, including detection of hepatitis C virus and biological warfare. The last 5 manuscripts describe current issues in molecular cardiovascular disease, including assessing thrombotic risk, genomic analysis, gene therapy, and a device for aiding in cardiac angiogenesis. DATA SYNTHESIS Novel problem-solving techniques have been used in the past and will be required in the future in DNA discovery. The extraction of DNA from clotted blood demonstrates a potential cost-effective strategy. Cybrids created from mitochondrial DNA-depleted cells and mitochondrial DNA from a platelet donor have been useful in defining the role mitochondria play in neurodegeneration. Mitochondrial depletion has been reported as a genetically inherited disorder or after human immunodeficiency virus therapy. Hepatitis C viral detection by qualitative, quantitative, or genotyping techniques is useful clinically. Preparedness for potential biological warfare is a responsibility of all clinical laboratorians. Thrombotic risk in cardiovascular disorders may be assessed by coagulation screening assays and further defined by mutation analysis for specific genes for prothrombin and factor V Leiden. Gene therapy for reducing arteriosclerotic risk has been hindered primarily by complications introduced by the vectors used to introduce the therapeutic genes. Neovascularization in cardiac muscle with occluded vessels represents a promising method for recovery of viable tissue following ischemia. CONCLUSIONS The sequence of the human genome was reported by 2 groups in February 2001. The postgenomic era will emphasize the use of microarrays and database software for genomic and proteomic screening in the search for useful clinical assays. The number of molecular pathologic techniques and assays will expand as additional disease-associated mutations are defined. Gene therapy and tissue engineering will represent successful therapeutic adjuncts.
Collapse
Affiliation(s)
- Frederick L Kiechle
- Department of Clinical Pathology, William Beaumont Hospital, Royal Oak, MI 48073-6769, USA.
| | | |
Collapse
|
7
|
Dopazo J, Mendoza A, Herrero J, Caldara F, Humbert Y, Friedli L, Guerrier M, Grand-Schenk E, Gandin C, de Francesco M, Polissi A, Buell G, Feger G, García E, Peitsch M, García-Bustos JF. Annotated draft genomic sequence from a Streptococcus pneumoniae type 19F clinical isolate. Microb Drug Resist 2002; 7:99-125. [PMID: 11442348 DOI: 10.1089/10766290152044995] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
Abstract
The public availability of numerous microbial genomes is enabling the analysis of bacterial biology in great detail and with an unprecedented, organism-wide and taxon-wide, broad scope. Streptococcus pneumoniae is one of the most important bacterial pathogens throughout the world. We present here sequences and functional annotations for 2.1-Mbp of pneumococcal DNA, covering more than 90% of the total estimated size of the genome. The sequenced strain is a clinical isolate resistant to macrolides and tetracycline. It carries a type 19F capsular locus, but multilocus sequence typing for several conserved genetic loci suggests that the strain sequenced belongs to a pneumococcal lineage that most often expresses a serotype 15 capsular polysaccharide. A total of 2,046 putative open reading frames (ORFs) longer than 100 amino acids were identified (average of 1,009 bp per ORF), including all described two-component systems and aminoacyl tRNA synthetases. Comparisons to other complete, or nearly complete, bacterial genomes were made and are presented in a graphical form for all the predicted proteins.
Collapse
Affiliation(s)
- J Dopazo
- Research Department, GlaxoSmithKline S.A., Tres Cantos, Spain
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Hoskins J, Alborn WE, Arnold J, Blaszczak LC, Burgett S, DeHoff BS, Estrem ST, Fritz L, Fu DJ, Fuller W, Geringer C, Gilmour R, Glass JS, Khoja H, Kraft AR, Lagace RE, LeBlanc DJ, Lee LN, Lefkowitz EJ, Lu J, Matsushima P, McAhren SM, McHenney M, McLeaster K, Mundy CW, Nicas TI, Norris FH, O'Gara M, Peery RB, Robertson GT, Rockey P, Sun PM, Winkler ME, Yang Y, Young-Bellido M, Zhao G, Zook CA, Baltz RH, Jaskunas SR, Rosteck PR, Skatrud PL, Glass JI. Genome of the bacterium Streptococcus pneumoniae strain R6. J Bacteriol 2001; 183:5709-17. [PMID: 11544234 PMCID: PMC95463 DOI: 10.1128/jb.183.19.5709-5717.2001] [Citation(s) in RCA: 563] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2001] [Accepted: 07/13/2001] [Indexed: 01/30/2023] Open
Abstract
Streptococcus pneumoniae is among the most significant causes of bacterial disease in humans. Here we report the 2,038,615-bp genomic sequence of the gram-positive bacterium S. pneumoniae R6. Because the R6 strain is avirulent and, more importantly, because it is readily transformed with DNA from homologous species and many heterologous species, it is the principal platform for investigation of the biology of this important pathogen. It is also used as a primary vehicle for genomics-based development of antibiotics for gram-positive bacteria. In our analysis of the genome, we identified a large number of new uncharacterized genes predicted to encode proteins that either reside on the surface of the cell or are secreted. Among those proteins there may be new targets for vaccine and antibiotic development.
Collapse
Affiliation(s)
- J Hoskins
- Infectious Diseases Research and Clinical Investigation, Eli Lilly and Company, Indianapolis, Indiana 46285, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Hakenbeck R, Balmelle N, Weber B, Gardès C, Keck W, de Saizieu A. Mosaic genes and mosaic chromosomes: intra- and interspecies genomic variation of Streptococcus pneumoniae. Infect Immun 2001; 69:2477-86. [PMID: 11254610 PMCID: PMC98182 DOI: 10.1128/iai.69.4.2477-2486.2001] [Citation(s) in RCA: 172] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Streptococcus pneumoniae remains a major causative agent of serious human diseases. The worldwide increase of antibiotic resistant strains revealed the importance of horizontal gene transfer in this pathogen, a scenario that results in the modulation of the species-specific gene pool. We investigated genomic variation in 20 S. pneumoniae isolates representing major antibiotic-resistant clones and 10 different capsular serotypes. Variation was scored as decreased hybridization signals visualized on a high-density oligonucleotide array representing 1,968 genes of the type 4 reference strain KNR.7/87. Up to 10% of the genes appeared altered between individual isolates and the reference strain; variability within clones was below 2.1%. Ten gene clusters covering 160 kb account for half of the variable genes. Most of them are associated with transposases and are assumed to be part of a flexible gene pool within the bacterial population; other variable loci include mosaic genes encoding antibiotic resistance determinants and gene clusters related to bacteriocin production. Genomic comparison between S. pneumoniae and commensal Streptococcus mitis and Streptococcus oralis strains indicates distinct antigenic profiles and suggests a smooth transition between these species, supporting the validity of the microarray system as an epidemiological and diagnostic tool.
Collapse
Affiliation(s)
- R Hakenbeck
- Universität Kaiserslautern, D-67663 Kaiserslautern, Germany.
| | | | | | | | | | | |
Collapse
|
10
|
Wizemann TM, Heinrichs JH, Adamou JE, Erwin AL, Kunsch C, Choi GH, Barash SC, Rosen CA, Masure HR, Tuomanen E, Gayle A, Brewah YA, Walsh W, Barren P, Lathigra R, Hanson M, Langermann S, Johnson S, Koenig S. Use of a whole genome approach to identify vaccine molecules affording protection against Streptococcus pneumoniae infection. Infect Immun 2001; 69:1593-8. [PMID: 11179332 PMCID: PMC98061 DOI: 10.1128/iai.69.3.1593-1598.2001] [Citation(s) in RCA: 240] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microbial targets for protective humoral immunity are typically surface-localized proteins and contain common sequence motifs related to their secretion or surface binding. Exploiting the whole genome sequence of the human bacterial pathogen Streptococcus pneumoniae, we identified 130 open reading frames encoding proteins with secretion motifs or similarity to predicted virulence factors. Mice were immunized with 108 of these proteins, and 6 conferred protection against disseminated S. pneumoniae infection. Flow cytometry confirmed the surface localization of several of these targets. Each of the six protective antigens showed broad strain distribution and immunogenicity during human infection. Our results validate the use of a genomic approach for the identification of novel microbial targets that elicit a protective immune response. These new antigens may play a role in the development of improved vaccines against S. pneumoniae.
Collapse
Affiliation(s)
- T M Wizemann
- MedImmune, Inc., Gaithersburg, Maryland 20878, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
McAllister KA, Peery RB, Meier TI, Fischl AS, Zhao G. Biochemical and molecular analyses of the Streptococcus pneumoniae acyl carrier protein synthase, an enzyme essential for fatty acid biosynthesis. J Biol Chem 2000; 275:30864-72. [PMID: 10903317 DOI: 10.1074/jbc.m004475200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acyl carrier protein synthase (AcpS) is an essential enzyme in the biosynthesis of fatty acids in all bacteria. AcpS catalyzes the transfer of 4'-phosphopantetheine from coenzyme A (CoA) to apo-ACP, thus converting apo-ACP to holo-ACP that serves as an acyl carrier for the biosynthesis of fatty acids and lipids. To further understand the physiological role of AcpS, we identified, cloned, and expressed the acpS and acpP genes of Streptococcus pneumoniae and purified both products to homogeneity. Both acpS and acpP form operons with the genes whose functions are required for other cellular metabolism. The acpS gene complements an Escherichia coli mutant defective in the production of AcpS and appears to be essential for the growth of S. pneumoniae. Gel filtration and cross-linking analyses establish that purified AcpS exists as a homotrimer. AcpS activity was significantly stimulated by apo-ACP at concentrations over 10 microm and slightly inhibited at concentrations of 5-10 microm. Double reciprocal analysis of initial velocities of AcpS at various concentrations of CoA or apo-ACP indicated a random or compulsory ordered bi bi type of reaction mechanism. Further analysis of the inhibition kinetics of the product (3',5'-ADP) suggested that it is competitive with respect to CoA but mixed (competitive and noncompetitive) with respect to apo-ACP. Finally, apo-ACP bound tightly to AcpS in the absence of CoA, but CoA failed to do so in the absence of apo-ACP. Together, these results suggest that AcpS may be allosterically regulated by apo-ACP and probably proceeds by an ordered reaction mechanism with the first formation of the AcpS-apo-ACP complex and the subsequent transfer of 4'-phosphopantetheine to the apo-ACP of the complex.
Collapse
Affiliation(s)
- K A McAllister
- Lilly Research Laboratories, the Eli Lilly and Company, Indianapolis, Indiana 46285, USA
| | | | | | | | | |
Collapse
|
12
|
Abstract
Biochemical, serological and microbiological methods have been used to dissect pathogens and identify the components useful for vaccine development. Although successful in many cases, this approach is time-consuming and fails when the pathogens cannot be cultivated in vitro, or when the most abundant antigens are variable in sequence. Now genomic approaches allow prediction of all antigens, independent of their abundance and immunogenicity during infection, without the need to grow the pathogen in vitro. This allows vaccine development using non-conventional antigens and exploiting non-conventional arms of the immune system. Many vaccines impossible to develop so far will become a reality. Since the process of vaccine discovery starts in silico using the genetic information rather than the pathogen itself, this novel process can be named reverse vaccinology.
Collapse
Affiliation(s)
- R Rappuoli
- IRIS, Chiron S.p.A., Via Fiorentina 1, 53100, Siena, Italy.
| |
Collapse
|
13
|
Hoskins J, Matsushima P, Mullen DL, Tang J, Zhao G, Meier TI, Nicas TI, Jaskunas SR. Gene disruption studies of penicillin-binding proteins 1a, 1b, and 2a in Streptococcus pneumoniae. J Bacteriol 1999; 181:6552-5. [PMID: 10515951 PMCID: PMC103796 DOI: 10.1128/jb.181.20.6552-6555.1999] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effects of inactivation of the genes encoding penicillin-binding protein 1a (PBP1a), PBP1b, and PBP2a in Streptococcus pneumoniae were examined. Insertional mutants did not exhibit detectable changes in growth rate or morphology, although a pbp1a pbp1b double-disruption mutant grew more slowly than its parent did. Attempts to generate a pbp1a pbp2a double-disruption mutant failed. The pbp2a mutants, but not the other mutants, were more sensitive to moenomycin, a transglycosylase inhibitor. These observations suggest that individually the pbp1a, pbp1b, and pbp2a genes are dispensable but that either pbp1a or pbp2a is required for growth in vitro. These results also suggest that PBP2a is a functional transglycosylase in S. pneumoniae.
Collapse
Affiliation(s)
- J Hoskins
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USA.
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Clemans DL, Kolenbrander PE, Debabov DV, Zhang Q, Lunsford RD, Sakone H, Whittaker CJ, Heaton MP, Neuhaus FC. Insertional inactivation of genes responsible for the D-alanylation of lipoteichoic acid in Streptococcus gordonii DL1 (Challis) affects intrageneric coaggregations. Infect Immun 1999; 67:2464-74. [PMID: 10225909 PMCID: PMC115992 DOI: 10.1128/iai.67.5.2464-2474.1999] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/1998] [Accepted: 02/25/1999] [Indexed: 11/20/2022] Open
Abstract
Most human oral viridans streptococci participate in intrageneric coaggregations, the cell-to-cell adherence among genetically distinct streptococci. Two genes relevant to these intrageneric coaggregations were identified by transposon Tn916 mutagenesis of Streptococcus gordonii DL1 (Challis). A 626-bp sequence flanking the left end of the transposon was homologous to dltA and dltB of Lactobacillus rhamnosus ATCC 7469 (formerly called Lactobacillus casei). A 60-kb probe based on this flanking sequence was used to identify the homologous DNA in a fosmid library of S. gordonii DL1. This DNA encoded D-alanine-D-alanyl carrier protein ligase that was expressed in Escherichia coli from the fosmid clone. The cloned streptococcal dltA was disrupted by inserting an ermAM cassette, and then it was linearized and transformed into S. gordonii DL1 for allelic replacement. Erythromycin-resistant transformants containing a single insertion in dltA exhibited a loss of D-alanyl esters in lipoteichoic acid (LTA) and a loss of intrageneric coaggregation. This phenotype was correlated with the loss of a 100-kDa surface protein reported previously to be involved in mediating intrageneric coaggregation (C. J. Whittaker, D. L. Clemans, and P. E. Kolenbrander, Infect. Immun. 64:4137-4142, 1996). The mutants retained the parental ability to participate in intergeneric coaggregation with human oral actinomyces, indicating the specificity of the mutation in altering intrageneric coaggregations. The mutants were altered morphologically and exhibited aberrant cell septa in a variety of pleomorphs. The natural DNA transformation frequency was reduced 10-fold in these mutants. Southern analysis of chromosomal DNAs from various streptococcal species with the dltA probe revealed the presence of this gene in most viridans streptococci. Thus, it is hypothesized that D-alanyl LTA may provide binding sites for the putative 100-kDa adhesin and scaffolding for the proper presentation of this adhesin to mediate intrageneric coaggregation.
Collapse
MESH Headings
- Adhesins, Bacterial/genetics
- Adhesins, Bacterial/metabolism
- Amino Acid Sequence
- Bacterial Adhesion/genetics
- Bacterial Adhesion/physiology
- Base Sequence
- Cloning, Molecular
- DNA Primers/genetics
- DNA Transposable Elements/genetics
- DNA, Bacterial/genetics
- Genes, Bacterial
- Humans
- Microscopy, Electron
- Microscopy, Electron, Scanning
- Molecular Sequence Data
- Mouth/microbiology
- Mutagenesis, Insertional
- Sequence Homology, Amino Acid
- Streptococcus/genetics
- Streptococcus/metabolism
- Streptococcus/ultrastructure
- Teichoic Acids/biosynthesis
Collapse
Affiliation(s)
- D L Clemans
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Abstract
The complete pneumococcal genome sequence was released in November, 1997. This advance has been combined with new understanding of physiology and pathogenesis including characterization of a family of surface proteins adducted to choline, regulation of virulence, and the regulon for natural DNA transformation. These developments in our understanding of molecular and cellular biology of pneumococcal infection will allow the development of new vaccines and antibiotics against this community acquired pathogen.
Collapse
Affiliation(s)
- E Tuomanen
- Department of Infectious Diseases St Jude Children's Research Hospital 332 N Lauderdale Rd Memphis TN 38105 USA.
| |
Collapse
|
16
|
Chopra I, Storey C, Falla TJ, Pearce JH. Antibiotics, peptidoglycan synthesis and genomics: the chlamydial anomaly revisited. MICROBIOLOGY (READING, ENGLAND) 1998; 144 ( Pt 10):2673-2678. [PMID: 9802008 DOI: 10.1099/00221287-144-10-2673] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Ian Chopra
- Department of Microbiology and Antimicrobial Research Centre, University of LeedsLeeds LS2 9JTlUK
| | - Christopher Storey
- Department of Microbiology and Antimicrobial Research Centre, University of LeedsLeeds LS2 9JTlUK
| | - Timothy J Falla
- Department of Microbiology and Antimicrobial Research Centre, University of LeedsLeeds LS2 9JTlUK
| | - John H Pearce
- Microbial Molecular Genetics and Cell Biology Group, School of Biological Sciences, University of BirminghamBirmingham 815 21Tl UK
| |
Collapse
|