Project description:To use whole genome microarrays to compare the differences in genome contents of 5 B. pseudomallei isolated from clinical specimens and environmental sample with B. pseudomallei K96243 reference strain and reveals variable patterns of Genomic Islands (GIs) Keywords: Comparative genomic hybridization DNA microarrays were used to compare genome of clinical and environmental B. pseudomallei isolates with B. pseudomallei K96243 reference strain (B. pseudomallei K96243 vs. B. pseudmallei isolates). Each hybridization was used for comparison between B. pseudomallei K96243 as a reference strain with environmental isolate BP45s, environmental isolate BP28L, clinical isolate H307, clinical isolate P54, clinical isolate P82. Two replicate per array. Multiple hits with 90-99.99 % identity correspond to other locus are replicate of their genes were averaged and analyzed.
Project description:The gene expression profiles were investigated and compared in spleen, lungs and liver of susceptible (BALB/c) and resistant (C57BL/6) hosts to identify genes participated in survival and virulence functions encoded in the B. pseudomallei genome. Subsequently, genes with unknown function and located with virulence gene clusters or suspected to be transcription regulator were selected for a novel virulence gene investigation DNA microarray was used to compare gene expression profiles of B. pseudomallei 1909a in spleen, lung and liver of infection-susceptible BALB/c mice (Th2 prototype) and infection-resistant C57BL/6 mice, (Th1 prototype) during an acute infection. The gene expression profile of B. pseudomallei in culture medium at mid-log phase was used to identify genes that expressed higher or lower in vivo when compared to the in vitro gene profile KEYWORDS: Gene expression
Project description:Natural isolates of Burkholderia pseudomallei (Bp), the causative agent of melioidosis, are known to exhibit diverse phenotypic traits, suggesting significant intraspecies genetic heterogeneity. Using whole-genome Bp microarrays, we experimentally mapped patterns of large-scale genomic variation in 93 South East Asian clinical, environmental, and animal Bp isolates. 14% of the reference Bp K96243 genome was variably present across the strain panel, more than double previous estimates, and both hypothetical proteins and paralogous gene pairs (PGPs) were significantly over-represented in the set of strain-variable genes. Examining patterns of PGP retention and loss, we successfully sub-categorized the PGPs into non-redundant, functionally biased, and completely redundant classes. We then identified 20 novel regions (âislandsâ) variably present between strains previously missed by computational analysis. Three of these novel islands contained lipopolysaccharide (LPS) biosynthesis genes, and strains lacking one such LPS island demonstrated reduced virulence in mouse infection assays. Clinical isolates associated with human melioidosis were strongly associated with the presence of specific genomic islands, but a common set of virulence-related genes was present in all strains. Our results suggest that most Bp strains possess a core virulence machinery capable of causing disease, but accessory functions provided by mobile elements may predispose distinct host species and ecological niches to specific individual strains. This hierarchical model of Bp virulence reconciles previous conflicting studies comparing Bp environmental and clinical isolates, and suggests novel molecular strategies for disease surveillance and outbreak detection efforts in melioidosis. Keywords: aCGH of 93 Bp strains genomic DNA of 93 Bp strains were assessed on Bp_array_v2
Project description:The zur regulon in Neisseria meningitidis was elucidated in the strain MC58 using a zur knockout strain and conditions which activate Zur ( zinc supplementation in the medium) Common reference design, zur knock out strain was used as the common reference and the samples wild type strain grown in RPMI and in RPMI with Zinc supplementation were compared to the common reference.
Project description:The potential for epigenetic changes in host cells following microbial infection has been widely suggested, but few examples have been reported. We assessed genome-wide patterns of DNA methylation in human macrophage-like U937 cells following infection with Burkholderia pseudomallei, an intracellular bacterial pathogen and the causative agent of human melioidosis. Our analyses revealed significant changes in host cell DNA methylation, at multiple CpG sites in the host cell genome, following infection. Infection induced differentially methylated probes (iDMPs) showing the greatest changes in DNA methylation were found to be in the vicinity of genes involved in inflammatory responses, intracellular signalling, apoptosis and pathogen-induced signalling. A comparison of our data with reported methylome changes in cells infected with M. tuberculosis revealed commonality of differentially methylated genes, including genes involved in T cell responses (BCL11B, FOXO1, KIF13B, PAWR, SOX4, SYK), actin cytoskeleton organisation (ACTR3, CDC42BPA, DTNBP1, FERMT2, PRKCZ, RAC1), and cytokine production (FOXP1, IRF8, MR1). Overall our findings show that pathogenic-specific and pathogen-common changes in the methylome occur following infection. The human leukemic monocyte lymphoma cell line (U937, ATCC CRL-1593.2) was maintained in RPMI 1640 supplemented with 10% foetal bovine serum (FBS) at 37°C. U937 cells were differentiated to macrophage-like cells following exposure to 20 ng/ml (final concentration) of phorbol 12-myristate 13-acetate (PMA) for 48 hours at 37°C and differentiation evidenced by increased adherence to tissue culture flasks. Overnight cultures of B. pseudomallei K96243 were diluted in L-15 medium and added to differentiated U937 cells at a multiplicity of infection (MOI) of 10. Uninfected controls were overlaid with L15 medium only. The cells were then incubated at 37°C to allow infection. The cells were washed 3 times with PBS and incubated with fresh L15 medium containing 1mg/ml kanamycin to kill extracellular bacteria. At appropriate time points the cells were washed 3 times in warm PBS and lysed with 0.1% (vol/vol) Triton X-100. DNA was isolated using an AllPrep kit (Qiagen) and stored at -80ºC until required. DNA yield was measured using a Nanodrop instrument with measurements between 22.8 â 50.6 ng/ul. Two experiments were carried out using the above procedure. In Experiment 1, DNA was collected from uninfected and infected cells at 2 hours (T2), and 4 hours (T4) post infection (2 biological replicates and 2 technical replicates from each group). In Experiment 2, DNA was collected from uninfected and infected cells at 1 hour (T1), 2 hours (T2), 3 hours (T3) and 4 hours (T4) post infection (1 sample from each group). The DNA methylation profile was determined using the Infinium HumanMethylation450 BeadChip (450K) (Illumina Inc.) following the manufacturerâs instructions. The data was extracted and the initial analysis was performed using GenomeStudio (2010.3) methylation module (1.8.5). Quality control checks and quantile normalisation were implemented using WateRmelon. Samples with more than 1% of sites with a detection p-value greater than 0.05 were removed as were probes with 1% of samples with a detection p-value greater than 0.05. Probes were removed if they had a bead count less than 3 in 1% of samples. Cross-hybridizing probes were removed, leaving 425496 probes for analysis. Here we report DNA methylation profile of 18 samples (10 infected and 8 control).
Project description:Prostate cancer is one of the most commonly diagnosed cancers among men in the world and the pathogenesis of prostate cancer remains poorly understood. In this study, we intended to disclose chromosomal aberrations that might be involved in tumorigenesis, using cDNA microarray-based CGH technology. Keywords: disease state analysis A total of 18 experiments were performed without replicates, using a kidney tissue as normal references. Prostate tumors and normal references were labeled with Cy5-dCTP and Cy3-dCTP, respectively.
Project description:Over half of the mature hepatocytes in mice and humans are aneuploid and yet retain full ability to undergo mitosis. This observation has raised the question whether this unusual somatic genetic variation evolved as an adaptive mechanism to hepatic injury. According to this model, hepatotoxic insults would select for hepatocytes with specific numerical chromosome abnormalities, rendering them differentially resistant to the injury. To test this hypothesis, we utilized a strain of mice heterozygous for a mutation in homogentisic acid dioxygenase (Hgd), located on chromosome 16. Loss of this allele can protect from fumarylacetoacetate hydrolase (Fah) deficiency. When adult Hgd+/- Fah-/- mice were exposed to chronic liver damage, injury-resistant nodules consisting of Hgd-null hepatocytes rapidly emerged. To determine whether aneuploidy played a role in this phenomenon, array comparative genomic hybridization (aCGH) and metaphase karyotyping were performed. Strikingly, loss of chromosome 16 was dramatically enriched in all mice that became completely resistant to tyrosinemia-induced hepatic injury. The frequency of chromosome 16-specific aneuploidy was ~50%. This result provides proof-of-principle that the selection of a specific aneuploid karyotype can result in the adaptation of hepatocytes to chronic liver injury. The extent to which aneuploidy promotes hepatic adaptation in humans is under investigation. 8 mouse hepatocyte samples were analyzed. Genomic DNA samples were derived from wild type mice (2), Hgd-/- Fah-/- mice off NTBC (2) and Hgd+/- Fah-/- off NTBC (4). Samples were compared to sex-mismatched reference genomic DNA isolated from wild type mouse splenocytes.
Project description:identification of genetic differences and similarities between clinical isolates of s.pneumonie of the same sequence type and /or serotype
Project description:Data generated in the validation of a large-insert clone DNA microarray covering the entire human genome in tiling path resolution, which we have used to identify copy number variation in human populations. Array performance was extensively tested by a series of validation assays. These included determining the hybridization characteristics of each individual clone on the array by chromosome specific add-in experiments. Estimation of data reproducibility and falsepositive/negative rates was carried out using self-self hybridizations, replicate experiments and independent validations of CNVs.
Project description:The kinetic behaviour of S. pneumoniae during vaccine production was studied using a dynamic systemic approach. Quantification of key intracellular glycolytic metabolites coupled to global transcriptomic analysis led to an improved knowledge of pneumococcal physiology. In controlled growth conditions, a direct correlation between the accumulation of key glycolytic intermediates and the expression of capsular polysaccharide genes (cps operon encoding the main pneumococcal antigen) was established. Interestingly, the same correlation was confirmed for the genes involved in the assimilation and the modification of choline, an indispensable nutritional requirement for both growth and virulence of S. pneumoniae. Such a correlation suggests a direct or indirect control of the expression of these genes by the global transcriptional regulator CcpA (catabolite control protein A) since putative cre sites upstream of the promoter were identified, even though the exact nature of this regulation remains to be confirmed. Preliminary results indicate that a ccpA mutation provokes a significant decrease in the expression of these genes. The global transcriptomic analysis coupled with motif research has revealed an extended CcpA regulon in S. pneumoniae including genes involved in diverse metabolic functions. Keywords: Capsular polysaccharide industrial production One condition experiment examining the transcriptome between two growth phases of the same serotype (slide 1 to slide 4). Thus, cross analysis between the two serotypes during exponential growth was performed in order to complete the analysis