Whole phage genomes can be sequenced readily using one or a combination of next generation sequencing (NGS) technologies. One of the most recently developed NGS platforms, the so-called Single-Molecule Real-Time (SMRT) sequencing approach provided by the PacBio RS platform, is particularly useful in providing complete (i.e., un-gapped) genome sequences, but differs from other technologies in that the platform also allows for downstream analysis to identify nucleotides that have been modified by DNA methylation. Here, we describe the methodological approach for the detection of genomic methylation motifs by means of SMRT sequencing.
Metasecretome is a collection of cell-surface and secreted proteins that mediate interactions between microbial communities and their environment. These include adhesins, enzymes, surface structures such as pili or flagella, vaccine targets or proteins responsible for immune evasion. Traditional approaches to exploring matasecretome of complex microbial communities via cultivation of microorganisms and screening of individual strains fail to sample extraordinary diversity in these communities, since only a limited fraction of microorganisms are represented by cultures. Advances in culture-independent sequence analysis methods, collectively referred to as metagenomics, offer an alternative approach that enables the direct analysis of collective microbial genomes (metagenome) recovered…
In this study, we present the characterization and genomic data of three Achromobacter phages belonging to the family Siphoviridae. Phages 83-24, JWX and JWF were isolated from sewage samples in Paris and Braunschweig, respectively, and infect Achromobacter xylosoxidans, an emerging nosocomial pathogen in cystic fibrosis patients. Analysis of morphology and growth parameters revealed that phages 83-24 and JWX have similar properties, both have nearly the same head and tail measurements, and both have a burst size between 85 and 100 pfu/cell. In regard to morphological properties, JWF had a much longer and more flexible tail compared to other phages. The…
Legionella is a highly diverse genus of intracellular bacterial pathogens that cause Legionnaire's disease (LD), an often severe form of pneumonia. Two L. micdadei sp. clinical isolates, obtained from patients hospitalized with LD from geographically distinct areas, were sequenced using PacBio SMRT cell technology, identifying incomplete phage regions, which may impact virulence. Copyright © 2017 Osborne et al.
We report here a new type of plasmid that carries the mcr-1 gene, the pMCR-1-P3 plasmid, harbored in an Escherichia coli strain isolated from a pig farm in China. pMCR-1-P3 belongs to the IncY incompatibility group and is a phage-like plasmid that contains a large portion of phage-related sequences. The backbone of this plasmid is different from that of other mcr-1-carrying plasmids reported previously. Copyright © 2017 American Society for Microbiology.
Endogenous viral elements are increasingly found in eukaryotic genomes, yet little is known about their origins, dynamics, or function. Here we provide a compelling example of a DNA virus that readily integrates into a eukaryotic genome where it acts as an inducible antiviral defence system. We found that the virophage mavirus, a parasite of the giant Cafeteria roenbergensis virus (CroV), integrates at multiple sites within the nuclear genome of the marine protozoan Cafeteria roenbergensis. The endogenous mavirus is structurally and genetically similar to eukaryotic DNA transposons and endogenous viruses of the Maverick/Polinton family. Provirophage genes are not constitutively expressed, but…
Microbes drive ecosystem functioning and their viruses modulate these impacts through mortality, gene transfer and metabolic reprogramming. Despite the importance of virus-host interactions and likely variable infection efficiencies of individual phages across hosts, such variability is seldom quantified. Here, we quantify infection efficiencies of 38 phages against 19 host strains in aquatic Cellulophaga (Bacteroidetes) phage-host model systems. Binary data revealed that some phages infected only one strain while others infected 17, whereas quantitative data revealed that efficiency of infection could vary 10 orders of magnitude, even among phages within one population. This provides a baseline for understanding and modeling intrapopulation…
Clostridium pasteurianum is emerging as a prospective host for the production of biofuels and chemicals, and has recently been shown to directly consume electric current. Despite this growing biotechnological appeal, the organism's genetics and central metabolism remain poorly understood. Here we present a concurrent genome sequence for the C. pasteurianum type strain and provide extensive genomic analysis of the organism's defence mechanisms and central fermentative metabolism. Next generation genome sequencing produced reads corresponding to spontaneous excision of a novel phage, designated f6013, which could be induced using mitomycin C and detected using PCR and transmission electron microscopy. Methylome analysis of…
To investigate the potential evolutionary obstacles in the sustainable therapeutic use of plasmid-dependent phages to control the clinically important conjugative plasmid-mediated dissemination of antibiotic resistance genes to pathogenic bacteria.The lytic plasmid-dependent phage PRD1 and the multiresistance conferring plasmid RP4 in an Escherichia coli host were utilized to assess the genetic and phenotypic changes induced by combined phage and antibiotic selection.Resistance to PRD1 was always coupled with either completely lost or greatly reduced conjugation ability. Reversion to full conjugation efficiency was found to be rare, and it also restored the susceptibility to plasmid-dependent phages. Consequently, plasmid-dependent phages constitute an interesting candidate…
We report here the complete genome sequence, including five plasmid sequences, of Escherichia coli sequence type 131 (ST131) strain JJ1887. The strain was isolated in 2007 in the United States from a patient with recurrent cystitis, whose caregiver sister died from urosepsis caused by a nearly identical strain. Copyright © 2016 Johnson et al.
The Bacillus thuringiensis d-endotoxins (Bt toxins) are widely used insecticidal proteins in engineered crops that provide agricultural, economic, and environmental benefits. The development of insect resistance to Bt toxins endangers their long-term effectiveness. Here we have developed a phage-assisted continuous evolution selection that rapidly evolves high-affinity protein-protein interactions, and applied this system to evolve variants of the Bt toxin Cry1Ac that bind a cadherin-like receptor from the insect pest Trichoplusia ni (TnCAD) that is not natively bound by wild-type Cry1Ac. The resulting evolved Cry1Ac variants bind TnCAD with high affinity (dissociation constant Kd?=?11-41?nM), kill TnCAD-expressing insect cells that are not…
Here, we report the complete genome sequences of three Legionella pneumophila subsp. pascullei strains (including both serogroup 1 and 5 strains) that were found in the same health care facility in 1982 and 2012. Copyright © 2016 Kozak-Muiznieks et al.
The complete genome sequence of Salmonella enterica serovar Typhimurium strain SO2, isolated from an asymptomatic child in Mexico, was determined using PacBio single-molecule real-time technology. Strain SO2 has six complete chromosomal prophages, namely, ST104, Gifsy-2, ST64B, Gifsy-1, ELPhiS, and FSL SP-004, and carries a Salmonella virulence plasmid.
Isolated from coastal seawater from Yellow Sea of Korea, Celeribacter marinus IMCC12053 was used as the host bacterium for bacteriophage P12053L. Here we report the complete genome sequence of strain IMCC12053 for further study of the marine bacteriophage P12053L functional genes. Single molecule real-time technology (PacBio RSII) was used for the single circular chromosome that is 3,096,705 base pairs in length and the GC content is 56.24%. It contains 3155 ORFs with 45 tRNAs and 6 rRNAs genes. N(6)-methyladenosine patterns were also investigated for 32 unmethylated genes and intergenic regions that covered many regulators and phage genes as well as…
Modern industrial agriculture depends on high-density cultivation of genetically similar crop plants, creating favorable conditions for the emergence of novel pathogens with increased fitness in managed compared with ecologically intact settings. Here, we present the genome sequence of six strains of the cucurbit bacterial wilt pathogen Erwinia tracheiphila (Enterobacteriaceae) isolated from infected squash plants in New York, Pennsylvania, Kentucky, and Michigan. These genomes exhibit a high proportion of recent horizontal gene acquisitions, invasion and remarkable amplification of mobile genetic elements, and pseudogenization of approximately 20% of the coding sequences. These genome attributes indicate that E. tracheiphila recently emerged as a…