Project description:Comparative genomic hybridization between Escherichia coli strains to determine core and pan genome content of clinical and environmental isolates
Project description:We performed whole genome single nucleotide polymorphism (SNP) based analysis of all available Venezuelan equine encephalitis (VEE) virus antigenic complex genomes and developed a high resolution genome-wide SNP microarray. We used the SNP microarray to analyze a broad panel of VEEV isolates, found excellent concordance between array and sequence based genotypes for previously sequenced strains, and genotyped unsequenced strains.
Project description:The human respiratory tract pathogen M. pneumoniae is one of the best characterized minimal bacterium. Until now, two main groups of clinical isolates of this bacterium have been described (types 1 and 2), differing in the sequence of the P1 adhesin gene. Here, we have sequenced the genomes of 23 clinical isolates of M. pneumoniae. Studying SNPs, non-synonymous mutations, indels and genome rearrangements of these 23 strains and 4 previously sequenced ones, has revealed new subclasses in the two main groups, some of them being associated with the country of isolation. Integrative analysis of in vitro gene essentiality and mutation rates enabled the identification of several putative virulence factors and antigenic proteins; revealing recombination machinery, glycerol metabolism and peroxide production as key factors in the genetics and physiology of these pathogenic strains. Additionally, the transcriptomes and proteomes of two representative strains, one from each of the two main groups, have been characterized to evaluate the impact of mutations on RNA and proteins levels. This study has revealed that type 2 strains show high expression levels of CARDs toxin, a protein recently shown to be one of the major factors of inflammation. Thus, we propose that type 2 strains are likely to be more virulent than type 1 strains.
Project description:Ectromelia virus (ECTV) has emerged as a valuable model for investigating the host-orthopoxvirus relationship as it relates to pathogenesis and the immune response. ECTV causes mousepox in most strains of mice, including BALB/c and DBA/2, and these are therefore classified as susceptible mice. Conversely, C57BL/6 and certain 129 strains display limited pathology and a very low mortality, and are thus classified as resistant. To understand the host genetic factors of different mouse strains in response to ECTV infection, we carried out a microarray analysis using Affymetrix Gene-Chip Mouse Genome Arrays of spleen tissues from BALB/c and C57BL/6 mice at 3 and 10 days post-ECTV infection. Differential Expression of Genes (DEGs) analyses revealed distinct differences in the gene profiles of resistant and susceptible mice infected with ECTV. Gene ontology and KEGG pathway analysis showed that the DEGs of susceptible mice were involved mainly in immunity, apoptosis, spliceosomes and cancer-related pathways, while the DEGs of resistant mice were largely involved in MAPK signaling and leukocyte transendothelial migration. This suggests that the susceptible BALB/c mice have a stronger response than the resistant C57BL/6 mice to ECTV infection. The BALB/c mice showed a strong induction of interferon-induced genes (ISGs), including guanylate binding proteins (GBPs), myxovirus resistance protein (Mx) GTPases, oligoadenylate synthetase (OAS) and IFN-induced protein with tetratricopeptide repeats (IFIT) family proteins, while the C57BL/6 mice upregulated more genes related to metabolic pathways. This suggests that the susceptible BALB/c mice have a stronger response than the resistant C57BL/6 mice to ECTV infection.
Project description:Despite high vaccination coverage, pertussis is on the rise in many countries including Czech Republic. To better understand B. pertussis resurgence we compared the changes in genome structures between Czech vaccine and circulating strains and subsequently, we determined how these changes translated into global transcriptomic and proteomic profiles. The whole-genome sequencing revealed that both historical and recent isolates of B. pertussis display substantial variation in genome organization and cluster separately. The RNA-seq and LC-MS/MS analyses indicate that these variations translated into discretely separated transcriptomic and proteomic profiles. Compared to vaccine strains, recent isolates displayed increased expression of flagellar genes and decreased expression of polysaccharide capsule operon. Czech strains (Bp46, K10, Bp155, Bp318 and Bp6242)exhibited increased expression of T3SS and sulphate metabolism genes when compared to Tohama I. In spite of 50 years of vaccination the Czech vaccine strains (VS67, VS393 and VS401) differ from recent isolates to a lesser extent than from another vaccine strain Tohama I.
Project description:The human respiratory tract pathogen M. pneumoniae is one of the best characterized minimal bacterium. Until now, two main groups of clinical isolates of this bacterium have been described (types 1 and 2), differing in the sequence of the P1 adhesin gene. Here, we have sequenced the genomes of 23 clinical isolates of M. pneumoniae. Studying SNPs, non-synonymous mutations, indels and genome rearrangements of these 23 strains and 4 previously sequenced ones, has revealed new subclasses in the two main groups, some of them being associated with the country of isolation. Integrative analysis of in vitro gene essentiality and mutation rates enabled the identification of several putative virulence factors and antigenic proteins; revealing recombination machinery, glycerol metabolism and peroxide production as possible factors in the genetics and physiology of these pathogenic strains. Additionally, the transcriptomes and proteomes of two representative strains, one from each of the two main groups, have been characterized to evaluate the impact of mutations on RNA and proteins levels. This study has revealed that type 2 strains show higher expression levels of CARDS toxin, a protein recently shown to be one of the major factors of inflammation. Thus, we propose that type 2 strains could be more toxigenic than type 1 strains of M. pneumoniae.
Project description:High-coverage whole genome sequencing of 11 Brazilian isolates of the root-knot nematode Meloidogyne incognita, presenting different host plant preferences and different geographical origins. Four M. incognita host races had been proposed in the past, based on host (in)compatibility on four different plant strains. The objective was to assess whether genomic variations (SNP) correlate with host range compatibility, geographical origin and host plant of origin.
Project description:Bacterial persister cells are phenotypic variants of regular cells that are tolerant to antibiotics. Analysis of clinical isolates of M. tuberculosis showed that strains vary substantially in their tolerance to antibiotics. The level of persisters was very high is some isolates, suggesting that these are hip mutants. We investigated gene expression differences in eight clinical isolates, four of which we characterized as high-persister strains and four as low-persister, or regular, strains. Comparison of gene expression patterns may provide clues as to the genetic mechanisms underlying persister formation.
Project description:Salmonella enterica serovar Typhimurium (S. Typhimurium) definitive phage type 104 (DT104) has caused significant morbidity and mortality in humans and animals for almost three decades. We have completed the full DNA sequence of one DT104 strain, NCTC13348 and show that the main differences between the genome of this isolate and the previously sequenced S. Typhimurium LT2 lie in integrated prophage elements and the Salmonella Genomic Island 1 encoding antibiotic resistance genes. Thirteen isolates of S. Typhimurium DT104 with different pulsed field gel electrophoresis (PFGE) profiles were analyzed by multi locus sequence typing (MLST), plasmid profiling, hybridization to a Pan-Salmonella DNA microarray and prophage-based multiplex PCR. All the isolates belonged to a single MLST type ST19. Microarray data demonstrated that the 13 DT104 isolates were remarkably conserved in gene content. The PFGE band-size differences in these isolates could be explained to a great extent by changes in prophage and plasmid content. Thus, here the nature of variation in different S. Typhimurium DT104 isolates is further defined at the genome level illustrating how this phage type is evolving over time.