scholarly journals Genetic Analysis of Capsular Polysaccharide Synthesis Gene Clusters from All Serotypes of Streptococcus suis: Potential Mechanisms for Generation of Capsular Variation

2013 ◽  
Vol 79 (8) ◽  
pp. 2796-2806 ◽  
Author(s):  
Masatoshi Okura ◽  
Daisuke Takamatsu ◽  
Fumito Maruyama ◽  
Takashi Nozawa ◽  
Ichiro Nakagawa ◽  
...  
Keyword(s):  
Capsular Polysaccharide ◽  
Single Gene ◽  
Streptococcus Suis ◽  
Gene Clusters ◽  
Small Scale ◽  
Specific Gene ◽  
Chromosomal Locus ◽  
Content Type ◽  
Comprehensive Information ◽  
Genes Encoding

ABSTRACTStreptococcus suisstrains are classified into 35 serotypes on the basis of the antigenicity of their capsular polysaccharides (CPs). CP synthesis genes are known to be clustered on the chromosome (cpsgene cluster). The entirecpsgene clusters ofS. suishave so far been sequenced in 15 serotypes and found to be located betweenorfZandaroA. In this study, to provide comprehensive information aboutS. suisCPs, we sequenced the entirecpsgene clusters of the remaining serotypes and analyzed the complete set ofS. suiscpsgene clusters. Among the 35cpsgene clusters, 22 were located betweenorfZandaroA, whereas the other 13 were flanked by other gene(s) on the chromosomes, and the chromosomal locus was classified into five patterns. By clustering analysis, the predicted products ofcpsgenes found in the 35 serotypes were assigned into 291 homology groups, and all serotypes possessed a serotype-specific gene, except for serotypes 1, 2, 1/2, and 14. Because of the presence of genes encoding flippase (wzx) and polymerase (wzy), CPs of all serotypes were thought to be synthesized by the Wzx/Wzy pathway. Our data also implied the possibility of the transfer of the entire or partialcpsgene clusters amongS. suisstrains, as well as the influence of spontaneous mutations in a single gene or a few genes on the antigenicity of some serotypes. Accumulation of these gene transfers and small-scale mutations may have generated the antigenic diversity ofS. suisCPs.

scholarly journals Restoration of Bioactive Lantibiotic Suicin from a RemnantlanLocus of Pathogenic Streptococcus suis Serotype 2

2013 ◽  
Vol 80 (3) ◽  
pp. 1062-1071 ◽  
Author(s):  
Jian Wang ◽  
Yong Gao ◽  
Kunling Teng ◽  
Jie Zhang ◽  
Shutao Sun ◽  
...  
Keyword(s):  
Gene Promoter ◽  
Streptococcus Suis ◽  
Gene Clusters ◽  
Disulfide Bridge ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
System A ◽  
Bactericidal Activities

ABSTRACTLantibiotics are ribosomally synthesized, posttranslationally modified antimicrobial peptides. Their biosynthesis genes are usually organized in gene clusters, which are mainly found in Gram-positive bacteria, including pathogenic streptococci. Three highly virulentStreptococcus suisserotype 2 strains (98HAH33, 05ZYH33, and SC84) have been shown to contain an 89K pathogenicity island. Here, on these islands, we unveiled and reannotated a putative lantibiotic locus designatedsuiwhich contains a virulence-associated two-component regulator,suiK-suiR. In silicoanalysis revealed that the putative lantibiotic modification genesuiMwas interrupted by a 7.9-kb integron and that other biosynthesis-related genes contained various frameshift mutations. By reconstituting the intactsuiMinEscherichia colitogether with a semi-in vitrobiosynthesis system, a putative lantibiotic named suicin was produced with bactericidal activities against a variety of Gram-positive strains, including pathogenic streptococci and vancomycin-resistant enterococci. Ring topology dissection indicated that the 34-amino-acid lantibiotic contained two methyllanthionine residues and one disulfide bridge, which render suicin in an N-terminal linear and C-terminal globular shape. To confirm the function ofsuiK-suiR, SuiR was overexpressed and purified.In vitroanalysis showed that SuiR could specifically bind to thesuiAgene promoter. Its coexpression withsuiKcould activatesuiAgene promoter inLactococcus lactisNZ9000. Conclusively, we obtained a novel lantibiotic suicin by restoring its production from the remnantsuilocus and demonstrated that virulence-associated SuiK-SuiR regulates its production.

scholarly journals Two Gene Clusters Coordinate Galactose and Lactose Metabolism in Streptococcus gordonii

2012 ◽  
Vol 78 (16) ◽  
pp. 5597-5605 ◽  
Author(s):  
Lin Zeng ◽  
Nicole C. Martino ◽  
Robert A. Burne
Keyword(s):  
Gene Clusters ◽  
Selective Advantage ◽  
Streptococcus Gordonii ◽  
Phosphotransferase System ◽  
Content Type ◽  
High Affinity ◽  
Oral Biofilms ◽  
Genes Encoding ◽  
Complex Regulation ◽  
Galactose Utilization

ABSTRACTStreptococcus gordoniiis an early colonizer of the human oral cavity and an abundant constituent of oral biofilms. Two tandemly arranged gene clusters, designatedlacandgal, were identified in theS. gordoniiDL1 genome, which encode genes of the tagatose pathway (lacABCD) and sugar phosphotransferase system (PTS) enzyme II permeases. Genes encoding a predicted phospho-β-galactosidase (LacG), a DeoR family transcriptional regulator (LacR), and a transcriptional antiterminator (LacT) were also present in the clusters. Growth and PTS assays supported that the permease designated EIILactransports lactose and galactose, whereas EIIGaltransports galactose. The expression of the gene for EIIGalwas markedly upregulated in cells growing on galactose. Using promoter-catfusions, a role for LacR in the regulation of the expressions of both gene clusters was demonstrated, and thegalcluster was also shown to be sensitive to repression by CcpA. The deletion oflacTcaused an inability to grow on lactose, apparently because of its role in the regulation of the expression of the genes for EIILac, but had little effect on galactose utilization.S. gordoniimaintained a selective advantage overStreptococcus mutansin a mixed-species competition assay, associated with its possession of a high-affinity galactose PTS, althoughS. mutanscould persist better at low pHs. Collectively, these results support the concept that the galactose and lactose systems ofS. gordoniiare subject to complex regulation and that a high-affinity galactose PTS may be advantageous whenS. gordoniiis competing against the caries pathogenS. mutansin oral biofilms.

scholarly journals Genetic Analysis of Mutacin B-Ny266, a Lantibiotic Active against Caries Pathogens

2020 ◽  
Vol 202 (12) ◽  
Author(s):  
Delphine Dufour ◽  
Abdelahhad Barbour ◽  
Yuki Chan ◽  
Marcus Cheng ◽  
Taimoor Rahman ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Dental Caries ◽  
Streptococcus Mutans ◽  
Dental Plaque ◽  
Oral Bacteria ◽  
Oral Streptococci ◽  
Chromosomal Locus ◽  
Content Type ◽  
Genes Encoding ◽  
Plaque Biofilm

ABSTRACT Bacteriocins are ribosomally synthesized proteinaceous antibacterial peptides. They selectively interfere with the growth of other bacteria. The production and secretion of bacteriocins confer a distinct ecological advantage to the producer in competing against other bacteria that are present in the same ecological niche. Streptococcus mutans, a significant contributor to the development of dental caries, is one of the most prolific producers of bacteriocins, known as mutacins in S. mutans. In this study, we characterized the locus encoding mutacin B-Ny266, a lantibiotic with a broad spectrum of activity. The chromosomal locus is composed of six predicted operon structures encoding proteins involved in regulation, antimicrobial activity, biosynthesis, modification, transport, and immunity. Mutacin B-Ny266 was purified from semisolid cultures, and two inhibitory peptides, LanA and LanA′, were detected. Both peptides were highly modified. Such modifications include dehydration of serine and threonine and the formation of a C-terminal aminovinyl-cysteine (AviCys) ring. While LanA peptide alone is absolutely required for antimicrobial activity, the presence of LanA′ enhanced the activity of LanA, suggesting that B-Ny266 may function as a two-peptide lantibiotic. The activation of lanAA′ expression is most likely controlled by the conserved two-component system NsrRS, which is activated by LanA peptide but not by LanA′. The chromosomal locus encoding mutacin B-Ny266 was not universally conserved in all sequenced S. mutans genomes. Intriguingly, the genes encoding LanAA′ peptides were restricted to the most invasive serotypes of S. mutans. IMPORTANCE Although dental caries is largely preventable, it remains the most common and costly infectious disease worldwide. Caries is initiated by the presence of dental plaque biofilm that contains Streptococcus mutans, a species extensively characterized by its role in caries development and formation. S. mutans deploys an arsenal of strategies to establish itself within the oral cavity. One of them is the production of bacteriocins that confer a competitive advantage by targeting and killing closely related competitors. In this work, we found that mutacin B-Ny266 is a potent lantibiotic that is effective at killing a wide array of oral streptococci, including nearly all S. mutans strains tested. Lantibiotics produced by oral bacteria could represent a promising strategy to target caries pathogens embedded in dental plaque biofilm.

scholarly journals Complement Susceptibility in Relation to Genome Sequence of RecentKlebsiella pneumoniaeIsolates from Thai Hospitals

mSphere ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Jessica Loraine ◽  
Eva Heinz ◽  
Jessica De Sousa Almeida ◽  
Oleksandr Milevskyy ◽  
Supayang P. Voravuthikunchai ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Single Gene ◽  
Multidrug Resistant ◽  
Side Chains ◽  
Content Type ◽  
Genes Encoding ◽  
Resistance Patterns ◽  
Tertiary Hospitals ◽  
Population Structures ◽  
Antibiotic Resistance Patterns

ABSTRACTThe capacity to resist the bactericidal action of complement (C′) is a strong but poorly understood virulence trait inKlebsiellaspp. Killing requires activation of one or more C′ pathways, assembly of C5b-9 membrane attack complexes (MACs) on the surface of the outer membrane (OM), and penetration of MACs into the target bilayer. We interrogated whole-genome sequences of 164Klebsiellaisolates from three tertiary hospitals in Thailand for genes encoding surface-located macromolecules considered to play a role in determination of C′ resistance. Most isolates (154/164) were identified asKlebsiella pneumoniae, and the collection conformed to previously established population structures and antibiotic resistance patterns. The distribution of sequence types (STs) and capsular (K) types were also typical of global populations. The majority (64%) of isolates were resistant to C′, and the remainder were either rapidly or slowly killed. All isolates carried genes encoding capsular polysaccharides (K antigens), which have been strongly linked to C′ resistance. In contrast to previous reports, there were no differences in the amount of capsule produced by C′-resistant isolates compared to C′-susceptible isolates, nor was there any correlation between serum reactivity and the presence of hypermucoviscous capsules. Similarly, there were no correlations between the presence of genes specifying lipopolysaccharide O-side chains or major OM proteins. Some virulence factors were found more frequently in C′-resistant isolates but were considered to reflect clonal ST expansion. Thus, no single gene accounts for the C′ resistance of the isolates sequenced in this study.IMPORTANCEMultidrug-resistantKlebsiella pneumoniaeis responsible for an increasing proportion of nosocomial infections, and emerging hypervirulentK. pneumoniaeclones now cause severe community-acquired infections in otherwise healthy individuals. These bacteria are adept at circumventing immune defenses, and most survive and grow in serum; their capacity to avoid C′-mediated destruction is correlated with their invasive potential. Killing of Gram-negative bacteria occurs following activation of the C′ cascades and stable deposition of C5b-9 MACs onto the OM. ForKlebsiella, studies with mutants and conjugants have invoked capsules, lipopolysaccharide O-side chains, and OM proteins as determinants of C′ resistance, although the precise roles of the macromolecules are unclear. In this study, we sequenced 164Klebsiellaisolates with different C′ susceptibilities to identify genes involved in resistance. We conclude that no single OM constituent can account for resistance, which is likely to depend on biophysical properties of the target bilayer.

scholarly journals Novel Variant Serotype of Streptococcus suis Isolated from Piglets with Meningitis

2014 ◽  
Vol 81 (3) ◽  
pp. 976-985 ◽  
Author(s):  
Zihao Pan ◽  
Jiale Ma ◽  
Wenyang Dong ◽  
Wenchao Song ◽  
Kaicheng Wang ◽  
...  
Keyword(s):  
Eastern China ◽  
Streptococcus Suis ◽  
Gene Clusters ◽  
The Other ◽  
Adhesion Assay ◽  
Content Type ◽  
High Fatality Rate ◽  
Novel Variant ◽  
Severe Infections ◽  
Serum Agglutination

ABSTRACTStreptococcus suisis an emerging zoonotic pathogen causing severe infections in pigs and humans. In previous studies, 33 serotypes ofS. suishave been identified using serum agglutination. Here, we describe a novelS. suisstrain, CZ130302, isolated from an outbreak of acute piglet meningitis in eastern China. Strong pathogenicity of meningitis caused by strain CZ130302 was reproduced in the BALB/c mouse model. The strain showed a high fatality rate (8/10), higher than those for known virulent serotype 2 strains P1/7 (1/10) and 9801 (2/10). Cell adhesion assay results with bEnd.3 and HEp2 cells showed that CZ130302 was significantly close to P1/7 and 9801. Both the agglutination test and its complementary test showed that strain CZ130302 had no strong cross-reaction with the other 33S. suisserotypes. The multiplex PCR assays revealed no specified bands for all four sets used to detect the other 33 serotypes. In addition, genetic analysis of the wholecpsgene clusters of all serotypes was performed in this study. The results of comparative genomics showed that thecpsgene cluster of CZ130302, which was not previously reported, showed no homology to the gene sequences of the other strains. Especially, thewzy,wzx, and acetyltransferase genes of strain CZ130302 are phylogenetically distinct from strains of the other 33 serotypes. Therefore, this study suggested that strain CZ130302 represents a novel variant serotype ofS. suis(designated serotype Chz) which has a high potential to be virulent and associated with meningitis in animals.

scholarly journals Genetic, Biochemical, and Serological Characterization of a New Pneumococcal Serotype, 6H, and Generation of a Pneumococcal Strain Producing Three Different Capsular Repeat Units

2015 ◽  
Vol 22 (3) ◽  
pp. 313-318 ◽  
Author(s):  
In Ho Park ◽  
K. Aaron Geno ◽  
Jigui Yu ◽  
Melissa B. Oliver ◽  
Kyung-Hyo Kim ◽  
...  
Keyword(s):  
Capsular Polysaccharide ◽  
Vaccine Coverage ◽  
Repeat Unit ◽  
Enzyme Specificity ◽  
Content Type ◽  
Repeat Units ◽  
Novel Approach ◽  
Serological Characterization ◽  
Pneumococcal Strain ◽  
Genes Encoding

ABSTRACTStreptococcus pneumoniaeclinical isolates were recently described that produced capsular polysaccharide with properties of both serotypes 6A and 6B. Their hybrid serological property correlated with mutations affecting the glycosyltransferase WciP, which links rhamnose to ribitol by an α(1-3) linkage for serotypes 6A and 6C and an α(1-4) linkage for serotypes 6B and 6D. The isolates had mutations in the triad residues of WciP that have been correlated with enzyme specificity. The canonical triad residues of WciP are Ala192-Ser195-Arg254 for serotypes 6A and 6C and Ser192-Asn195-Gly254 for serotypes 6B and 6D. To prove that the mutations in the triad residues are responsible for the hybrid serotype, we introduced the previously described Ala192-Cys195-Arg254 triad into a 6A strain and found that the change made WciP bispecific, resulting in 6A and 6B repeat unit expression, although 6B repeat unit production was favored over production of 6A repeat units. Likewise, this triad permitted a 6C strain to express 6C and 6D repeat units. With reported bispecificity in WciN, which adds either glucose or galactose as the second sugar in the serogroup 6 repeat unit, the possibility exists for a strain to simultaneously produce all four serogroup 6 repeat units; however, when genes encoding both bispecific enzymes were introduced into a 6A strain, only 6A, 6B, and 6D repeat units were detected serologically. Nonetheless, this may be the first example of a bacterial polysaccharide with three different repeat units. This strategy of expressing multiple repeat units in a single polymer is a novel approach to broadening vaccine coverage by eliminating the need for multiple polysaccharide sources to cover multiple serogroup members.

scholarly journals Novel Capsular Polysaccharide Loci and New Diagnostic Tools for High-Throughput Capsular Gene Typing in Streptococcus suis

2016 ◽  
Vol 82 (24) ◽  
pp. 7102-7112 ◽  
Author(s):  
Xiaotong Qiu ◽  
Xuemei Bai ◽  
Ruiting Lan ◽  
Han Zheng ◽  
Jianguo Xu
Keyword(s):  
Genetic Information ◽  
Capsular Polysaccharide ◽  
Detection System ◽  
Cost Effective ◽  
Streptococcus Suis ◽  
Epidemiological Studies ◽  
Diagnostic Tools ◽  
Genetic Characteristics ◽  
Content Type ◽  
Gene Typing

ABSTRACTStreptococcus suisis an important pathogen of pigs and may cause serious disease in humans. Serotyping is an important tool for detection and epidemiological studies ofS. suis. Thirty-three reference serotypes and nine novelcpsloci (NCLs) are recognized inS. suis. To gain a better understanding of the prevalence and genetic characteristics of NCLs, we investigated the serotype identity of 486 isolates isolated between 2013 and 2015 in China by capsular gene typing methods. Two hundred seventy-six isolates carried NCLs belonging to 16 groups, 8 of which appear to have not been reported previously. These isolates showed autoagglutination, polyagglutination, or nonagglutination with reference antisera and thus were nonserotypeable. Almost all isolates carrying the unknown NCLs were encapsulated, with various capsular thicknesses, indicating that they are most likely novel serotypes. To simultaneously identify the currently recognized 17 NCLs, an 18-plex detection system using the Luminex xTAG universal array technology was developed. Our data also provide valuable genetic information for monitoring the variations within NCLs by investigating the genetic characteristics of different subtypes within NCLs.IMPORTANCENonserotypeableStreptococcus suisisolates have been reported in many studies, and 9 novelcpsloci (NCLs) have already been identified in nonserotypeable isolates. Moreover, novelcpsloci are continually being found. The main purpose of this study was to investigate the prevalence and characteristics of NCLs inS. suisisolates recovered between 2013 and 2015 in China. This study provides valuable genetic information for monitoring the variations within NCLs. Meanwhile, a fast and cost-effective 18-plex detection system that can simultaneously identify the currently recognized 17 NCLs was developed in this study. This system will serve as a valuable tool for detecting known and identifying additional novelcpsloci among nonserotypeableS. suisisolates.

scholarly journals Evolution of Chemical Diversity in Echinocandin Lipopeptide Antifungal Metabolites

2015 ◽  
Vol 14 (7) ◽  
pp. 698-718 ◽  
Author(s):  
Qun Yue ◽  
Li Chen ◽  
Xiaoling Zhang ◽  
Kuan Li ◽  
Jingzu Sun ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Incomplete Lineage Sorting ◽  
Gene Clusters ◽  
Antifungal Drugs ◽  
Chemical Diversity ◽  
Specific Gene ◽  
Gene Trees ◽  
Content Type ◽  
Antifungal Metabolites ◽  
Pathway Gene

ABSTRACTThe echinocandins are a class of antifungal drugs that includes caspofungin, micafungin, and anidulafungin. Gene clusters encoding most of the structural complexity of the echinocandins provided a framework for hypotheses about the evolutionary history and chemical logic of echinocandin biosynthesis. Gene orthologs among echinocandin-producing fungi were identified. Pathway genes, including the nonribosomal peptide synthetases (NRPSs), were analyzed phylogenetically to address the hypothesis that these pathways represent descent from a common ancestor. The clusters share cooperative gene contents and linkages among the different strains. Individual pathway genes analyzed in the context of similar genes formed unique echinocandin-exclusive phylogenetic lineages. The echinocandin NRPSs, along with the NRPS from theinpgene cluster inAspergillus nidulansand its orthologs, comprise a novel lineage among fungal NRPSs. NRPS adenylation domains from different species exhibited a one-to-one correspondence between modules and amino acid specificity that is consistent with models of tandem duplication and subfunctionalization. Pathway gene trees and Ascomycota phylogenies are congruent and consistent with the hypothesis that the echinocandin gene clusters have a common origin. The disjunct Eurotiomycete-Leotiomycete distribution appears to be consistent with a scenario of vertical descent accompanied by incomplete lineage sorting and loss of the clusters from most lineages of theAscomycota. We present evidence for a single evolutionary origin of the echinocandin family of gene clusters and a progression of structural diversification in two fungal classes that diverged approximately 290 to 390 million years ago. Lineage-specific gene cluster evolution driven by selection of new chemotypes contributed to diversification of the molecular functionalities.

scholarly journals Distribution of Suicin Gene Clusters in Streptococcus suis Serotype 2 Belonging to Sequence Types 25 and 28

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Taryn B. T. Athey ◽  
Katy Vaillancourt ◽  
Michel Frenette ◽  
Nahuel Fittipaldi ◽  
Marcelo Gottschalk ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Streptococcus Suis ◽  
Gene Clusters ◽  
Sequence Type ◽  
Purification And Characterization ◽  
Heterogeneous Distribution ◽  
Genes Encoding ◽  
Sequence Types ◽  
Suis Serotype

Recently, we reported the purification and characterization of three distinct lantibiotics (named suicin 90-1330, suicin 3908, and suicin 65) produced by Streptococcus suis. In this study, we investigated the distribution of the three suicin lantibiotic gene clusters among serotype 2 S. suis strains belonging to sequence type (ST) 25 and ST28, the two dominant STs identified in North America. The genomes of 102 strains were interrogated for the presence of suicin gene clusters encoding suicins 90-1330, 3908, and 65. The gene cluster encoding suicin 65 was the most prevalent and mainly found among ST25 strains. In contrast, none of the genes related to suicin 90-1330 production were identified in 51 ST25 strains nor in 35/51 ST28 strains. However, the complete suicin 90-1330 gene cluster was found in ten ST28 strains, although some genes in the cluster were truncated in three of these isolates. The vast majority (101/102) of S. suis strains did not possess any of the genes encoding suicin 3908. In conclusion, this study indicates heterogeneous distribution of suicin genes in S. suis.

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