Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1090041 | ENA |
REPOSITORIES: ENA
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Project description:Transposon-directed insertion-site sequencing (TraDIS) of a 1 million mutant library of Salmonella Typhi
| PRJEB2004 | ENA
Project description:A whole genome screen was used to assay every gene of Escherichia coli strain BW25113 to identify genes involved in susceptibility to the monobactam (beta-lactam) antibiotic aztreonam. The methodology has been called TraDIS-Xpress, and is a version of TraDIS or Tn-seq. A transposon mutant library consisting of several hundred thousand mutants was constructed using a Tn5-derived transposon incorporating an inducible outward transcribing promoter. All the mutants were grown in LB broth cultures supplemented with aztreonam at 2 x, 1 x, 0.5 x and 0.25 x MIC with induction of the transposon promoter using 0.2 mM IPTG or 1 mM IPTG or without induction. Following growth, mutants with increased susceptibility show reduced numbers and those with reduced susceptibility show increased numbers. Each condition was performed in duplicate. The methodology enable genes to be assayed by insertional inactivation or by changes in expression. Expression changes result from altered transcription from upstream transposon insertions transcribing into the gene, or downstream insertions transcribing into the gene in the reverse direction leading to RNA interference through the generation of reverse and complementary RNA. Thus, essential genes into which transposon insertions are not tolerated may be assayed also by changes in numbers of upstream or downstream insertion mutants. Changes to high throughput sequencing protocols permit the generation of nucleotide sequence reads from the known transposon sequences into the surrounding insertion site for all the mutants in the mixture simultaneously. Matching the sequence of the reads to the genome nucleotide sequence of E. coli BW25113 then allows the precise locations of all the transposon insertion sites of all the mutants to be mapped simultaneously. The relative changes in mutants between control (without) and selective condition (with aztreonam) then indicates which genes are involved in susceptibility. The numbers of sequence reads that match is reflected by the number of mutants, and so the degree of susceptibility can also be estimated.
2024-07-06 | E-MTAB-11576 | biostudies-arrayexpress
Project description:Generation of a Tn5 transposon library in Haemophilus parasuis and analysis by Transposon-Directed Insertion-Site Sequencing (TraDIS)
| PRJEB4161 | ENA
Project description:Enterotoxigeneic Escherichia coli (ETEC) is a leading cause of diarrhoeal infections in young children living in endemic regions in low and middle-income countries and adults travelling to these destinations. CFA/I fimbriae have been identified as the predominant colonisation factor associated with human ETEC infections. Here we used used Transposon-directed insertion-site sequencing (TraDIS) and transcriptomic analysis to identify the essential genome of the prototypical CFA/I expressing ETEC strain H10407 and uncover the survival mechanisms that enhance persistence of ETEC isolates in water and within mammalian hosts. RNA transcription profiles of H10407 were identified under different in vitro growth conditions including aerobic growth in neutral LB media (pH7); aerobic growth in acidic media (pH5); aerobic growth in alkaline media (pH9); anaerobic growth in neutral LB media (pH7); and survival in fresh water. Research work including RNA preparation and bioinformatics and statistical analyses were conducted at the Wellcome Trust Sanger Institute (WTSI) and the Westmead Institute for Medical Research (WIMR), the University of Sydney. The sequencing data was generated in the Bioscience Core Laboratory at King Abdullah University of Science and Technology (KAUST).
2021-04-21 | E-MTAB-9364 | biostudies-arrayexpress
Project description:Pasteurella multocida is a Gram-negative capsulated bacterium responsible for a range of diseases that cause severe morbidity and mortality in livestock animals. The hyaluronic acid (HA) capsule produced by P. multocida serogroup A strains is a critical virulence factor. In this study, we utilised transposon-directed insertion site sequencing (TraDIS) to identify genes essential for in vitro growth of P. multocida, and combined TraDIS with discontinuous density gradients (TraDISort) to identify genes required for HA capsule production and regulation in this pathogen. Analysis of mutants with a high cell density phenotype, indicative of the loss of extracellular capsule, led to the identification of 69 genes important for capsule production. These genes included all previously characterized genes in the capsule biosynthesis locus, and fis and hfq that encode known positive regulators of P. multocida capsule. Many of the other capsule-associated genes identified in this study were involved in regulation or activation of the stringent response, including spoT and relA that encode proteins that regulate the concentration of guanosine alarmones. Disruption of the autoregulatory domains in the C-terminal half of SpoT using insertional mutagenesis resulted in reduced expression of capsule biosynthesis genes and an acapsular phenotype. Overall, these findings have greatly increased the understanding of hyaluronic acid capsule production and regulation in P. multocida.
2022-03-14 | GSE198087 | GEO
Project description:Transposon insertion site sequencing (TIS) is a powerful method for associating genotype to phenotype. However, all TIS methods described to date use short nucleotide sequence reads which cannot uniquely determine the locations of transposon insertions within repeating genomic sequences where the repeat units are longer than the sequence read length. To overcome this limitation, we have developed a TIS method using Oxford Nanopore sequencing technology that generates and uses long nucleotide sequence reads; we have called this method LoRTIS (Long Read Transposon Insertion-site Sequencing). This experiment data contains sequence files generated using Nanopore and Illumina platforms. Biotin1308.fastq.gz and Biotin2508.fastq.gz are fastq files generated from nanopore technology. Rep1-Tn.fastq.gz and Rep1-Tn.fastq.gz are fastq files generated using Illumina platform. In this study, we have compared the efficiency of two methods in identification of transposon insertion sites.
2022-05-30 | E-MTAB-11351 | biostudies-arrayexpress
Project description:Streptococcus pneumoniae is a major cause of serious infections such as pneumonia and meningitis in both children and adults worldwide. Here, we describe the development of a high-throughput genome-wide technique, Genomic Array Footprinting (GAF), for the identification of genes essential for this bacterium at various stages during infection. GAF enables negative screens by means of a combination of transposon mutagenesis and microarray technology for the detection of transposon insertion sites. We tested several methods for the identification of transposon insertion sites and found that amplification of DNA adjacent to the insertion site by PCR resulted in non-reproducible results, even when combined with an adapter. However, restriction of genomic DNA followed directly by in vitro transcription circumvented these problems. Analysis of parallel reactions generated with this method on a large mariner transposon library, showed that it was highly reproducible and correctly identified essential genes. Comparison of a mariner library to one generated with the in vivo transposition plasmid pGh:ISS1, showed that both have an equal degree of saturation, but that 9% of the genome is preferentially mutated by either one. The usefulness of GAF was demonstrated in a screen for genes essential for survival of zinc stress. This identified a gene encoding a putative cation efflux transporter, and its deletion resulted in an inability to grow under high zinc conditions. In conclusion, we developed a fast, versatile, specific, and high-throughput method for the identification of conditionally essential genes in S. pneumoniae. Keywords: GAF Identification of transposon insertion sites
2007-06-26 | GSE6913 | GEO
Project description:Bacterial nutrition is a key aspect of host-pathogen interaction and bacteria must adapt to use nutrients available in the host. Lipid droplets-derived fatty acids are considered the major intracellular carbon source for Mycobacterium tuberculosis (Mtb), an intracellular pathogen causing Tuberculosis disease. However, many other (and more soluble) substrates are available in vivo and may represent alternative carbon sources. Lactate and pyruvate are rather abundant in human cells and fluids and represent two possible candidates. In this work, we employed a “multi-omics” approach (Transposon Directed Insertion Site Sequencing (TraDIS), RNA-seq transcriptomics, proteomics and stable isotopic labelling coupled with mass spectrometry-based metabolomics) and classic microbial physiology to study Mtb metabolism of lactate and pyruvate. We discovered that Mtb is well adapted to use lactate and pyruvate as sole carbon sources and that it requires gluconeogenesis, Krebs cycle, GABA shunt, glyoxylate shunt and methylcitrate cycle for their metabolism. These latter are traditionally associated with fatty acid metabolism and unexpectedly, we found that methylcitrate cycle operates in reverse. This latter discovery changes the role of this pathway making it a direct route for the biosynthesis of propionyl-CoA, the essential precursor for the biosynthesis of odd-chain fatty acids, abundantly present in Mtb cell envelope.
2020-05-26 | PXD010726 | Pride