Project description:Our data demonstrate the suitability of target capture technology for purifying very low quantities of Leptospira DNA from biological samples where the human genome is in vast excess. This enables deep sequencing of partial Leptospira genomes directly from clinical samples using next generation technologies and genotyping.
Project description:The genome of two isogenic lines from Aedes aegypti from Ile Royale, French Guiana, with a marked difference in resistance to deltamethrin was investigated in order to understand the genetic basis of this phenotypic difference. Genomic sequencing was performed both with Illumina short, paired reads and with Minion long reads.
Project description:Pathogenic Leptospira spp. are the causative agents of the zoonotic disease leptospirosis. During infection, Leptospira are confronted with deadly reactive oxygen species (ROS). Withstanding ROS produced by the host innate immunity is an important strategy evolved by pathogenic Leptospira for persisting in and colonizing hosts. The peroxide stress regulator, PerR, represses genes involved in ROS defenses in L. interrogans. We have performed RNA sequencing in WT and perR mutant strains to characterize the L. interrogans adaptive response to hydrogen peroxide. We showed that Leptospira solicit three main peroxidase machineries (catalase, cytochrome C peroxidase and peroxiredoxin) and heme to adapt to peroxide stress as well as canonical chaperones of the heat shock response, and DNA repair. Determining the PerR regulon allowed to identify the PerR-dependent mechanisms of the peroxide adaptive response and has revealed a regulatory network involving other transcriptional regulators, two-component systems and sigma factors as well as non-coding RNAs that putatively orchestrate, in concert with PerR, this adaptive response. Our findings provide comprehensive insight into the mechanisms required by pathogenic Leptospira to overcome infection-related oxidants. This will participate in framing future hypothesis-driven studies to identify and decipher novel virulence mechanisms.
Project description:The LRGASP challenge encompasses different human, mouse, and manatee samples sequenced using multiple combinations of protocols and platforms. Different challenges will use distinct subsets of the samples for evaluation. The long-read sequencing platforms used in these challenges are the Pacific Biosciences (PacBio) Sequel II, Oxford Nanopore (ONT) MinION and PromethION. Samples will also be sequenced on the Illumina HiSeq 2500. The primary LRGASP library prep protocols are “standard” cDNA sequencing, direct RNA sequencing, R2C2, and CapTrap. Each sample will also include Lexogen SIRV-Set 4 spike-ins. We will also provide simulated PacBio and ONT data as part of the evaluations. This particular study focuses on single strand CAGE sequencing of human iPSCs, defining CAGE peaks from Illumina HiSeq 2500 (SR: 150 cycles) of two biological replicates for use in the LRGASP challenge.
Project description:Leptospira are emerging zoonotic pathogens transmitted from animals to humans typically through contaminated environmental sources of water and soil. Transcriptional regulation of pathogenic Leptospira spp. underlying the adaptive response to different hosts and environmental conditions remains elusive. In this study, we provide the first global Transcriptional Start Site (TSS) map of a Leptospira species. RNA was obtained from the pathogen Leptospira interrogans grown at 30° (optimal in vitro temperature) and 37°C (host temperature) and selectively enriched for 5' ends of native transcripts. Primary TSS (pTSS) was identified for 2,865 genes, accounting for 67% of the total genome. The majority of the TSSs were located between 0 to 10 nucleotides from the translational start site. Comparative dRNA-seq analysis revealed conservation of most pTSS at 30° and 37°C. Promoter prediction algorithms allow the identification of the binding sites of the alternative sigma factor sigma 54. However, other motifs were not identified indicating that Leptospira consensus promoter sequences are inherently different from the E. coli model. RNA sequencing also identified 277 and 226 putative small regulatory RNAs (sRNAs) at 30°C and 37°C, respectively, including 8 validated sRNAs by Northern blots. These results provide the first global view of transcriptional start sites and the repertoire of sRNAs in L. interrogans, and will establish a foundation for future experimental work on gene regulation under various environmental conditions including those in the host.
Project description:S. meliloti strains with a bi- and monopartite genome configuration were constructed by consecutive Cre/lox-mediated site-specific fusions of the secondary replicons. Beside the correct genomic arrangements, these strains and precursors were tested for variations in the nucleotide sequence. Futher, a marker fequency analysis was performed to test if replication is initiated at all origins and to determine the replication termination regions of the triple replicon fusion molecule. To gain the sequence data for these analyses, respective strains were applied to whole genome sequencing using an Illumina MiSeq-System and Oxford Nanopore (MinION) sequencing technology.
Project description:To evaluate targeted MinION next generation sequencing as a diagnostic method for detection of pathogens in human blood and plasma, human blood or plasma samples were spiked with measured amounts of viruses, bacteria, protozoan parasites or tested pathogen-free as negative controls. Nucleic acid was extracted from samples and PCR amplification performed in multiplex primer pools with a procedure described in ArrayExpress experiment submission ID 18379. The PCR products were used for library preparation. The libraries sequenced on an Oxford Nanopore MinION. The passed reads aligned with a custom reference file to determine the identity of the pathogen in the sample.