Genomic Changes and Genetic Divergence of Vibrio alginolyticus Under Phage Infection Stress Revealed by Whole-Genome Sequencing and Resequencing

Bacteriophages (phages) and their bacterial hosts were the most abundant and genetically highly diverse organisms on the earth. In this study, a series of phage-resistant mutant (PRM) strains derived from Vibrio alginolyticus were isolated and Infrequent-restriction-site PCR (IRS-PCR) was used to investigate the genetic diversity of the PRM strains. Phenotypic variations of eight PRM strains were analyzed using profiles of utilizing carbon sources and chemical sensitivity. Genetic variations of eight PRM strains and coevolved V. alginolyticus populations with phages were analyzed by whole-genome sequencing and resequencing, respectively. The results indicated that eight genetically discrepant PRM stains exhibited abundant and abundant phenotypic variations. Eight PRM strains and coevolved V. alginolyticus populations (VE1, VE2, and VE3) contained numerous single nucleotide variations (SNVs) and insertions/indels (InDels) and exhibited obvious genetic divergence. Most of the SNVs and InDels in coding genes were related to the synthesis of flagellar, extracellular polysaccharide (EPS), which often served as the receptors of phage invasion. The PRM strains and the coevolved cell populations also contained frequent mutations in tRNA and rRNA genes. Two out of three coevolved populations (VE1 and VE2) contained a large mutation segment severely deconstructing gene nrdA, which was predictably responsible for the booming of mutation rate in the genome. In summary, numerous mutations and genetic divergence were detected in the genomes of V. alginolyticus PRM strains and in coevolved cell populations of V. alginolyticus under phage infection stress. The phage infection stress may provide an important force driving genomic evolution of V. alginolyticus.

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Quantifying the influence of mutation detection on tumour subclonal reconstruction

Nature Communications ◽

10.1038/s41467-020-20055-w ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Lydia Y. Liu ◽

Vinayak Bhandari ◽

Adriana Salcedo ◽

Shadrielle M. G. Espiritu ◽

Quaid D. Morris ◽

...

Keyword(s):

Whole Genome Sequencing ◽

Cancer Cells ◽

Clinical Outcomes ◽

Cancer Cell ◽

Genome Sequencing ◽

Somatic Mutations ◽

Mutation Detection ◽

Cell Populations ◽

Whole Genome ◽

Prostate Cancers

AbstractWhole-genome sequencing can be used to estimate subclonal populations in tumours and this intra-tumoural heterogeneity is linked to clinical outcomes. Many algorithms have been developed for subclonal reconstruction, but their variabilities and consistencies are largely unknown. We evaluate sixteen pipelines for reconstructing the evolutionary histories of 293 localized prostate cancers from single samples, and eighteen pipelines for the reconstruction of 10 tumours with multi-region sampling. We show that predictions of subclonal architecture and timing of somatic mutations vary extensively across pipelines. Pipelines show consistent types of biases, with those incorporating SomaticSniper and Battenberg preferentially predicting homogenous cancer cell populations and those using MuTect tending to predict multiple populations of cancer cells. Subclonal reconstructions using multi-region sampling confirm that single-sample reconstructions systematically underestimate intra-tumoural heterogeneity, predicting on average fewer than half of the cancer cell populations identified by multi-region sequencing. Overall, these biases suggest caution in interpreting specific architectures and subclonal variants.

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Quantifying the Influence of Mutation Detection on Tumour Subclonal Reconstruction

10.1101/418780 ◽

2018 ◽

Cited By ~ 2

Author(s):

Lydia Y. Liu ◽

Vinayak Bhandari ◽

Adriana Salcedo ◽

Shadrielle M. G. Espiritu ◽

Quaid D. Morris ◽

...

Keyword(s):

Whole Genome Sequencing ◽

Cancer Cells ◽

Clinical Outcomes ◽

Cancer Cell ◽

Genome Sequencing ◽

Somatic Mutations ◽

Mutation Detection ◽

Cell Populations ◽

Whole Genome ◽

Prostate Cancers

AbstractWhole-genome sequencing can be used to estimate subclonal populations in tumours and this intra-tumoural heterogeneity is linked to clinical outcomes. Many algorithms have been developed for subclonal reconstruction, but their variabilities and consistencies are largely unknown. We evaluated sixteen pipelines for reconstructing the evolutionary histories of 293 localized prostate cancers from single samples, and eighteen pipelines for the reconstruction of 10 tumours with multi-region sampling. We show that predictions of subclonal architecture and timing of somatic mutations vary extensively across pipelines. Pipelines show consistent types of biases, with those incorporating SomaticSniper and Battenberg preferentially predicting homogenous cancer cell populations and those using MuTect tending to predict multiple populations of cancer cells. Subclonal reconstructions using multi-region sampling confirm that single-sample reconstructions systematically underestimate intra-tumoural heterogeneity, predicting on average fewer than half of the cancer cell populations identified by multi-region sequencing. Overall, these biases suggest caution in interpreting specific architectures and subclonal variants.

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Imipenem Resistance Mediated by blaOXA-913 Gene in Pseudomonas aeruginosa

Antibiotics ◽

10.3390/antibiotics10101188 ◽

2021 ◽

Vol 10 (10) ◽

pp. 1188

Author(s):

Dong-Chan Moon ◽

Abraham Fikru Mechesso ◽

Hee-Young Kang ◽

Su-Jeong Kim ◽

Ji-Hyun Choi ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Resistance Genes ◽

Carbapenem Resistance ◽

Rrna Genes ◽

Whole Genome ◽

Translation Initiation Region ◽

Broth Microdilution Method ◽

Imipenem Resistance

Treatment of infectious diseases caused by carbapenem-resistant Pseudomonas aeruginosa is becoming a greater challenge. This study aimed to identify the imipenem resistance mechanism in P. aeruginosa isolated from a dog. Minimum Inhibitory Concentration (MIC) was determined by the broth microdilution method according to the Clinical and Laboratory Standards Institute recommendations. We performed polymerase chain reaction and whole-genome sequencing to detect carbapenem resistance genes. Genomic DNA of P. aeruginosa K19PSE24 was sequenced via the combined analysis of 20-kb PacBio SMRTbell and PacBio RS II. Peptide-Peptide Nucleic Acid conjugates (P-PNAs) targeting the translation initiation region of blaOXA-913 were synthesized. The isolate (K19PSE24) was resistant to imipenem and piperacillin/tazobactam yet was susceptible to most of the tested antimicrobials. Whole-genome sequencing revealed that the K19PSE24 genome comprised a single contig amounting to 6,815,777 base pairs, with 65 tRNA and 12 rRNA genes. K19PSE24 belonged to sequence type 313 and carried the genes aph(3)-IIb, fosA, catB7, crpP, and blaOXA-913 (an allele deposited in GenBank but not described in the literature). K19PSE24 also carried genes encoding for virulence factors (exoenzyme T, exotoxin A, and elastase B) that are associated with adhesion, invasion, and tissue lysis. Nevertheless, we did not detect any of the previously reported carbapenem resistance genes. This is the first report of the blaOXA-913 gene in imipenem-resistant P. aeruginosa in the literature. Notably, no viable colonies were found after co-treatment with imipenem (2 µg/mL) and either of the P-PNAs (12.5 µM or 25 µM). The imipenem resistance in K19PSE24 was primarily due to blaOXA-913 gene carriage.

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