Epigenetics expert Michael Jennings from Griffith University first posited the phasevarion, or the phase variable regulon mechanism in host-adapted pathogens. This mechanism switches expression of multiple genes in a coordinated fashion and has significant implications on pathogen virulence. In his talk, Jennings describes the phasevarion and his use of whole methylome data to rapidly identify methylation targets.
Jonas Korlach, CSO of PacBio, discusses the revival of finished genomes the microbial community will see with long read data, emphasizing that for certain organisms such as rapidly evolving microbes, having a de novo finished genome will be more useful than creating a draft based on a previous related reference genome. Korlach describes two bioinformatic methods from PacBio, a hierarchical genome assembly process (HGAP) and an consensus caller (Quiver), which are used to generate finished genomes from just long-read PacBio data, with final genome sequence accuracies over 99.999%. Korlach demonstrates the ability of PacBio data to generate closed, high-quality de…
In this AGBT plenary talk, Jonas Korlach presented a number of collaborative studies between PacBio and other institutions to make use of highly accurate, long-read sequence data, which has led to a revival of finished genomes. Examples from the infectious disease or pathogen realm included Pertussis, Salmonella, and Listeria, all of which now have closed genomes from PacBio-generated data. Korlach also reported on epigenomic information in Salmonella and Listeria, indicating potential new forms of DNA modifications.
Peter Evans from the US FDA shares insights on whole-genome sequencing for bacteria of importance to public health. Comparing data across PacBio, 454, and MiSeq sequencers, he says having closed genomes, long reads, and methylation patterns are critical for gleaning comprehensive information about a microbe.
Bart Weimer, a professor at the University of California, Davis, who is leading the 100K Foodborne Pathogen Genome Project, talks about using PacBio sequencing to produce long reads for microbial genomes as well as to study how bacteria use epigenetics to regulate gene expression.
UC Davis’s Bart Weimer describes foodborne pathogens and their proclivity for rapid genome rearrangement. The 100K Pathogen Genome Project he leads is using PacBio long-read sequencing to close genomes and analyze methylation; Weimer reports that his team has already discovered new epigenetic modifications in Salmonella and Listeria with the technology.
Ulf Gyllensten from Uppsala University used SMRT Sequencing to study multi-drug-resistant bacteria. Time to results was faster than other NGS platforms and generally resulted in complete genome assemblies, even for an organism with a 70% AT-rich genome. He also applied SMRT Sequencing for the characterization of HPV subtypes, important in cervical cancer.
Ulf Gyllensten speaks about advances in screening for HPV, his predictions for the widespread use of genome sequencing in the clinic, and applications using Single Molecule, Real-Time (SMRT) Sequencing for human genome studies.
Adam Ameur talks about a range of applications for which SMRT Sequencing had been useful in the SciLifeLab. Examples include analyzing a DNA translocation in chronic myeloid leukemia samples; studying the HPV genome; and sequencing the FADS region to understand fatty acid production.
At AGBT 2017, Lars Paulin from the University of Helsinki presented this poster on whole genome sequencing of the virus responsible for progressive multifocal leukoencephalopathy, a rare and dangerous brain infection. His team used long amplicon analysis to resolve the whole virus genome from three patient samples, pooled them for SMRT Sequencing, and identified variants and rearrangements. This work represents the first time the viral genome was sequenced from patients.
In this AGBT 2017 poster, the University of Helsinki’s Petri Auevinen reports on efforts to understand bacteria that grow on, and subsequently spoil, food. This analysis monitored DNA modifications and transcriptomic changes in three species of lactic acid bacteria. Scientists discovered that the organisms’ metabolic profiles change substantially when grown together compared to those cultured individually, and are now studying how Cas protein activity changes under these conditions too.
Culture-independent methods that target genome fragments have shown promise in identifying certain pathogens, but the holy grail of comprehensive pathogen genome detection from microbiologically complex samples for subsequent forensic analyses remains a challenge. In the context of an investigation of a nosocomial outbreak, we used shotgun metagenomic sequencing of a human fecal sample and a neural network algorithm based on tetranucleotide frequency profiling to reconstruct microbial genomes and tested the same approach using rectal swabs from a second patient. The approach rapidly and readily detected the genome of Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae in the patient fecal specimen and…
Acinetobacter has emerged recently as one of the most challenging nosocomial pathogens because of its increased rate of antimicrobial resistance. The genetic complexity and genome diversity, as well as the lack of adequate knowledge on the pathogenic determinants of Acinetobacter strains often hinder with pathogenesis studies for the development of better therapeutics to tackle this nosocomial pathogen.In this study, we comparatively analyzed the whole genome sequence of a virulent Acinetobacternosocomialis strain NCTC 8102.The genomic DNA of A. nosocomialis NCTC 8102 was isolated and sequenced using PacBio RS II platform. The sequenced genome was functionally annotated and gene prediction was carried…
Shiga toxin-producing Escherichia coli (STEC) is an emerging pathogen. Recently there has been a global in the number of outbreaks caused by non-O157 STECs, typically involving six serogroups O26, O45, 0103, 0111, and 0145. STEC O145:H28 has been associated with severe human disease including hemolytic-uremic syndrome (HUS), and is demonstrated by the 2007 Belgian ice-cream-associated outbreak and 2010 US lettuce-associated outbreak, with over 10% of patients developing HUS in each. The goal of this work was to do comparative genomics of strains, clinical and environmental, to investigate genome diversity and virulence evolution of this important foodborne pathogen.
The newer hierarchical genome assembly process (HGAP) performs de novo assembly using data from a single PacBio long insert library. To assess the benefits of this method, DNA from several Salmonella enterica serovars was isolated from a pure culture. Genome sequencing was performed using Pacific Biosciences RS sequencing technology. The HGAP process enabled us to close sixteen Salmonella subsp. enterica genomes and their associated mobile elements: The ten serotypes include: Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) S. Bareilly, S. Heidelberg, S. Cubana, S. Javiana and S. Typhimurium, S. Newport, S. Montevideo, S. Agona, and S. Tennessee. In addition,…