Project description:Background. As current methods for antibiotic drug discovery are being outpaced by the rise of antimicrobial resistance, new methods and innovative technologies are necessary to replenish our dwindling arsenal of antimicrobial agents. To this end, we developed the PepSAVI-MS pipeline to expedite the search for natural product bioactive peptides. Results. Herein we demonstrate expansion of PepSAVI-MS for the discovery of bacterial-sourced bioactive peptides through identification of the bacteriocin Bac-21 from Enterococcus faecalis pPD1. Minor pipeline modifications including implementation of bacteria-infused agar diffusion assays and optional digestion of peptide libraries highlight the versatility and wide adaptability of the PepSAVI-MS pipeline. Additionally, we have experimentally validated the primary protein sequence of the active, mature Bac-21 peptide for the first time and have confirmed identity with respect to primary sequence and post-translational processing. Conclusions: Successful application of PepSAVI-MS to bacterial secretomes as demonstrated herein establishes proof-of-principle for use in novel microbial bioactive peptide discovery.
Project description:We conducted a quantitative proteomic analysis of HGFs from early to late HSV-1 infection stage using DIA-based liquid chromatography-tandem mass spectrometry (LC-MS/MS). This work aimed to identify host factors variations and provide information on the various cellular and molecular pathways activated in HGFs. These results help to understand pathological process post HSV-1 infection in periodontal tissues and their potential role in pathogenic mechanisms.
Project description:Metagenomic sequence data from defined mock communities is crucial for the assessment of sequencing platform performance and downstream analyses, including assembly, binning and taxonomic assignment. We report a comparison of shotgun metagenome sequencing and assembly metrics of a defined microbial mock community using the Oxford Nanopore Technologies (ONT) MinION, PacBio and Illumina sequencing platforms. Our synthetic microbial community BMock12 consists of 12 bacterial strains with genome sizes spanning 3.2-7.2 Mbp, 40-73% GC content, and 1.5-7.3% repeats. Size selection of both PacBio and ONT sequencing libraries prior to sequencing was essential to yield comparable relative abundances of organisms among all sequencing technologies. While the Illumina-based metagenome assembly yielded good coverage with few misassemblies, contiguity was greatly improved by both, Illumina?+?ONT and Illumina?+?PacBio hybrid assemblies but increased misassemblies, most notably in genomes with high sequence similarity to each other. Our resulting datasets allow evaluation and benchmarking of bioinformatics software on Illumina, PacBio and ONT platforms in parallel.
Project description:Viral metagenomics has fuelled a rapid change in our understanding of global viral diversity and ecology. Long-read sequencing and hybrid assembly approaches that combine long- and short-read technologies are now being widely implemented in bacterial genomics and metagenomics. However, the use of long-read sequencing to investigate viral communities is still in its infancy. While Nanopore and PacBio technologies have been applied to viral metagenomics, it is not known to what extent different technologies will impact the reconstruction of the viral community. Thus, we constructed a mock bacteriophage community of previously sequenced phage genomes and sequenced them using Illumina, Nanopore and PacBio sequencing technologies and tested a number of different assembly approaches. When using a single sequencing technology, Illumina assemblies were the best at recovering phage genomes. Nanopore- and PacBio-only assemblies performed poorly in comparison to Illumina in both genome recovery and error rates, which both varied with the assembler used. The best Nanopore assembly had errors that manifested as SNPs and INDELs at frequencies 41 and 157 % higher than found in Illumina only assemblies, respectively. While the best PacBio assemblies had SNPs at frequencies 12 and 78 % higher than found in Illumina-only assemblies, respectively. Despite high-read coverage, long-read-only assemblies recovered a maximum of one complete genome from any assembly, unless reads were down-sampled prior to assembly. Overall the best approach was assembly by a combination of Illumina and Nanopore reads, which reduced error rates to levels comparable with short-read-only assemblies. When using a single technology, Illumina only was the best approach. The differences in genome recovery and error rates between technology and assembler had downstream impacts on gene prediction, viral prediction, and subsequent estimates of diversity within a sample. These findings will provide a starting point for others in the choice of reads and assembly algorithms for the analysis of viromes.
Project description:Primary human foreskin fibroblasts (HFF) were infected with wild-type herpes simplex virus 1 (HSV-1) strain 17 or its vhs null mutant, or with BAC-derived viruses expressing either a wild-type or catalytically inactive vhs with the D195N mutation at a multiplicity of infection (MOI) of 10. Chromatin-associated RNA was prepared and subjected to RNA-seq.
Project description:To obtain further insights into the role of bacterial activity in BAC filter performance, the expressed proteins of the bacterial community residing in the BAC filter were identified by a metaproteomic approach.