Project description:We report here the draft sequence of strain CEB14_0017, alias HIAD_DUP, recovered from a human patient and initially identified as Yersinia pestis by mass spectrometry analysis. Genotyping based on tandem repeat polymorphism assigned the strain to Yersinia pseudotuberculosis sequence type 42 (ST42). The total assembly length is 4,894,739 bp.
Project description:Here, we report the genome sequence of Yersinia pestis strain Cadman, an attenuated strain lacking the pgm locus. Y. pestis is the causative agent of plague and generally must be worked with under biosafety level 3 (BSL-3) conditions. However, strains lacking the pgm locus are considered safe to work with under BSL-2 conditions.
Project description:We report the complete genome assembly of Yersinia pestis subsp. <i>pestis</i> bv. Medievalis SCPM-O-B-6530, a strain belonging to the most ancient phylogenetic group (group 2.MED0) of Y. pestis subsp. <i>pestis</i> bv. Medievalis. This proline-dependent strain, carrying an additional plasmid (pCKF), was isolated from the Central-Caucasian high-mountain plague focus in Kabardino-Balkar Republic, Russia.
Project description:Yersinia pestis is among the most dangerous human pathogens, and systematic research of this pathogen is important in bacterial pathogenomics research. To fully interpret the biological functions, physiological characteristics, and pathogenesis of Y. pestis, a comprehensive annotation of its entire genome is necessary. The emergence of omics-based research has brought new opportunities to better annotate the genome of this pathogen. Here, the complete genome of Y. pestis strain 91001 was reannotated using genomics and proteogenomics data. One hundred and thirty-seven unreliable coding sequences were removed, and 41 homologous genes were relocated with their translational initiation sites, while the functions of seven pseudogenes and 392 hypothetical genes were revised. Moreover, annotations of noncoding RNAs, repeat sequences, and transposable elements have also been incorporated. The reannotated results are freely available at http://tody.bmi.ac.cn.
Project description:Purpose: In previous studies, we found that the fyuA gene plays an important role in the virulence and pathogenicity of Yersinia pestis strain 201. In order to globally observe which functions of the fyuA gene also affect Y. pestis, we performed RNA-seq on the Y. pestis wild strain 201-WT and mutant strains △fyuA and △fyuAGCAdel, hoping to find their differences at the transcription level, so that better elucidate the effect of fyuA gene on Y. pestis gene transcription. Methods: Total RNA was extracted using the PureLink™ RNA Mini Kit, and then used for creating a cDNA library and deep sequencing. According to the values of Fragments Per Kilobase of Transcript per Million Mapped Reads (FPKM), the ratio of transcript levels between WT and ΔfyuAGCAdel groups was used as the logarithm to the base 2 (twofold change). The differential values of at least a 2-fold were applied to analyze the differential expression of genes according to the Y. pestis 91001 genome annotation. The transcriptome data were verified by qPCR. Results: We found that compared with 201-WT, genes related to siderophore synthesis such as ybtS, ybtX, ybtQ, irp2, irp1, ybtU, ybtT and ybtE were significantly down-regulated at either 26 ℃ or 37 ℃. At 37 ℃, the genes related to type Ⅲ secretion system were significantly up-regulated. Overall design: Y. pestis WT strain 201 and fyuA mutants at 26 ℃ or 37 ℃ in TMH.
Project description:BACKGROUND: Whole genome sequencing allowed the development of a number of high resolution sequence based typing tools for Yersinia (Y.) pestis. The application of these methods on isolates from most known foci worldwide and in particular from China and the Former Soviet Union has dramatically improved our understanding of the population structure of this species. In the current view, Y. pestis including the non or moderate human pathogen Y. pestis subspecies microtus emerged from Yersinia pseudotuberculosis about 2,600 to 28,600 years ago in central Asia. The majority of central Asia natural foci have been investigated. However these investigations included only few strains from Mongolia. METHODOLOGY/PRINCIPAL FINDINGS: Clustered Regularly Interspaced Short Prokaryotic Repeats (CRISPR) analysis and Multiple-locus variable number of tandem repeats (VNTR) analysis (MLVA) with 25 loci was performed on 100 Y. pestis strains, isolated from 37 sampling areas in Mongolia. The resulting data were compared with previously published data from more than 500 plague strains, 130 of which had also been previously genotyped by single nucleotide polymorphism (SNP) analysis. The comparison revealed six main clusters including the three microtus biovars Ulegeica, Altaica, and Xilingolensis. The largest cluster comprises 78 isolates, with unique and new genotypes seen so far in Mongolia only. Typing of selected isolates by key SNPs was used to robustly assign the corresponding clusters to previously defined SNP branches. CONCLUSIONS/SIGNIFICANCE: We show that Mongolia hosts the most recent microtus clade (Ulegeica). Interestingly no representatives of the ancestral Y. pestis subspecies pestis nodes previously identified in North-western China were identified in this study. This observation suggests that the subsequent evolution steps within Y. pestis pestis did not occur in Mongolia. Rather, Mongolia was most likely re-colonized by more recent clades coming back from China contemporary of the black death pandemic, or more recently in the past 600 years.
Project description:Yersinia pestis is the causative agent of the plague. Y. pestis KIM 10+ strain was passaged and selected for loss of the 102 kb pgm locus, resulting in an attenuated strain, KIM D27. In this study, whole genome sequencing was performed on KIM D27 in order to identify any additional differences. Initial assemblies of 454 data were highly fragmented, and various bioinformatic tools detected between 15 and 465 SNPs and INDELs when comparing both strains, the vast majority associated with A or T homopolymer sequences. Consequently, Illumina sequencing was performed to improve the quality of the assembly. Hybrid sequence assemblies were performed and a total of 56 validated SNP/INDELs and 5 repeat differences were identified in the D27 strain relative to published KIM 10+ sequence. However, further analysis showed that 55 of these SNP/INDELs and 3 repeats were errors in the KIM 10+ reference sequence. We conclude that both 454 and Illumina sequencing were required to obtain the most accurate and rapid sequence results for Y. pestis KIMD27. SNP and INDELS calls were most accurate when both Newbler and CLC Genomics Workbench were employed. For purposes of obtaining high quality genome sequence differences between strains, any identified differences should be verified in both the new and reference genomes.
Project description:Yersinia pestis, the causative agent of plague, diverged from Yersinia pseudotuberculosis, an enteric pathogen, an estimated 1500-20,000 years ago. Genetic characterization of these closely related organisms represents a useful model to study the rapid emergence of bacterial pathogens that threaten mankind. To this end, we undertook genome-wide DNA microarray analysis of 22 strains of Y. pestis and 10 strains of Y. pseudotuberculosis of diverse origin. Eleven Y. pestis DNA loci were deemed absent or highly divergent in all strains of Y. pseudotuberculosis. Four were regions of phage origin, whereas the other seven included genes encoding a vitamin B12 receptor and the insect toxin sepC. Sixteen differences were identified between Y. pestis strains, with biovar Antiqua and Mediaevalis strains showing most divergence from the arrayed CO92 Orientalis strain. Fifty-eight Y. pestis regions were specific to a limited number of Y. pseudotuberculosis strains, including the high pathogenicity island, three putative autotransporters, and several possible insecticidal toxins and hemolysins. The O-antigen gene cluster and one of two possible flagellar operons had high levels of divergence between Y. pseudotuberculosis strains. This study reports chromosomal differences between species, biovars, serotypes, and strains of Y. pestis and Y. pseudotuberculosis that may relate to the evolution of these species in their respective niches.
Project description:Yersinia pestis is the causative agent of the bubonic plague, a disease responsible for several dramatic historical pandemics. Progress in ancient DNA (aDNA) sequencing rendered possible the sequencing of whole genomes of important human pathogens, including the ancient Y. pestis strains responsible for outbreaks of the bubonic plague in London in the 14th century and in Marseille in the 18th century, among others. However, aDNA sequencing data are still characterized by short reads and non-uniform coverage, so assembling ancient pathogen genomes remains challenging and often prevents a detailed study of genome rearrangements. It has recently been shown that comparative scaffolding approaches can improve the assembly of ancient Y. pestis genomes at a chromosome level. In the present work, we address the last step of genome assembly, the gap-filling stage. We describe an optimization-based method AGapEs (ancestral gap estimation) to fill in inter-contig gaps using a combination of a template obtained from related extant genomes and aDNA reads. We show how this approach can be used to refine comparative scaffolding by selecting contig adjacencies supported by a mix of unassembled aDNA reads and comparative signal. We applied our method to two Y. pestis data sets from the London and Marseilles outbreaks, for which we obtained highly improved genome assemblies for both genomes, comprised of, respectively, five and six scaffolds with 95?% of the assemblies supported by ancient reads. We analysed the genome evolution between both ancient genomes in terms of genome rearrangements, and observed a high level of synteny conservation between these strains.
Project description:Genome rearrangements have played an important role in the evolution of Yersinia pestis from its progenitor Yersinia pseudotuberculosis. Traditional phylogenetic trees for Y. pestis based on sequence comparison have short internal branches and low bootstrap supports as only a small number of nucleotide substitutions have occurred. On the other hand, even a small number of genome rearrangements may resolve topological ambiguities in a phylogenetic tree. We reconstructed phylogenetic trees based on genome rearrangements using several popular approaches such as Maximum likelihood for Gene Order and the Bayesian model of genome rearrangements by inversions. We also reconciled phylogenetic trees for each of the three CRISPR loci to obtain an integrated scenario of the CRISPR cassette evolution. Analysis of contradictions between the obtained evolutionary trees yielded numerous parallel inversions and gain/loss events. Our data indicate that an integrated analysis of sequence-based and inversion-based trees enhances the resolution of phylogenetic reconstruction. In contrast, reconstructions of strain relationships based on solely CRISPR loci may not be reliable, as the history is obscured by large deletions, obliterating the order of spacer gains. Similarly, numerous parallel gene losses preclude reconstruction of phylogeny based on gene content.