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Marnix H Medema
Microbial and plant specialized metabolites, also known as natural products, are key mediators of microbe-microbe and host-microbe interactions and constitute a rich resource for drug development. In the past decade, genome mining has emerged as a prominent strategy for natural product discovery. Initially, such mining was performed on the basis of individual microbial genome sequences. Now, these efforts are being scaled up to fully genome-sequenced strain collections, pangenomes of bacterial genera, and large sets of metagenome-assembled genomes from microbial communities...
March 2018: MSystems
Cecilia C Cundon, Alejandro Ameal, Elsa Maubecín, Adriana Bentancor
The pangenome of Escherichia coli is composed of a conserved core and variable genomic regions. The constant genetic component allows to determine the phylogeny of the microorganism, while genetic variability promoted the emergence of intestinal pathogenic strains and extraintestinal strains. In this study we characterized 85 extraintestinal pathogenic isolates genetically isolated from canines and felines. We used the Clermont scheme that includes intestinal (A and B1) and extraintestinal (B2 and D) phylogroups, virulence markers (pap1-2, pap3-4, sfa, afa, hlyA, aer and cnf) and hybrid pathogens...
March 15, 2018: Revista Argentina de Microbiología
Hannes Juergens, Javier A Varela, Arthur R Gorter de Vries, Thomas Perli, Veronica J M Gast, Nikola Y Gyurchev, Arun S Rajkumar, Robert Mans, Jack T Pronk, John P Morrissey, Jean-Marc G Daran
While CRISPR-Cas9-mediated genome editing has transformed yeast research, current plasmids and cassettes for Cas9 and guide-RNA expression are species specific. CRISPR tools that function in multiple yeast species could contribute to the intensifying research on non-conventional yeasts. A plasmid carrying a pangenomic origin of replication and two constitutive expression cassettes, for Cas9 and a ribozyme-flanked gRNAs was constructed. Its functionality was tested by analyzing inactivation of the ADE2 gene in four yeast species...
February 9, 2018: FEMS Yeast Research
Tom O Delmont, A Murat Eren
Pangenomes offer detailed characterizations of core and accessory genes found in a set of closely related microbial genomes, generally by clustering genes based on sequence homology. In comparison, metagenomes facilitate highly resolved investigations of the relative distribution of microbial genomes and individual genes across environments through read recruitment analyses. Combining these complementary approaches can yield unique insights into the functional basis of microbial niche partitioning and fitness, however, advanced software solutions are lacking...
2018: PeerJ
Gretchen L W Heavner, Cresten B Mansfeldt, Garrett E Debs, Sage T Hellerstedt, Annette R Rowe, Ruth E Richardson
Using mRNA transcript levels for key functional enzymes as proxies for the organohalide respiration (OHR) rate, is a promising approach for monitoring bioremediation populations in situ at chlorinated solvent-contaminated field sites. However, to date, no correlations have been empirically derived for chlorinated solvent respiring, Dehalococcoides mccartyi (DMC) containing, bioaugmentation cultures. In the current study, genome-wide transcriptome and proteome data were first used to confirm the most highly expressed OHR-related enzymes in the bioaugmentation culture, KB-1TM, including several reductive dehalogenases (RDases) and a Ni-Fe hydrogenase, Hup...
February 8, 2018: Microorganisms
David A Wilkinson, Andrew J O'Donnell, Rukhshana N Akhter, Ahmed Fayaz, Hamish J Mack, Lynn E Rogers, Patrick J Biggs, Nigel P French, Anne C Midwinter
Campylobacter hyointestinalis is a member of an emerging group of zoonotic Campylobacter spp. that are increasingly identified in both gastric and non-gastric disease in humans. Here, we discovered C. hyointestinalis in three separate classes of New Zealand ruminant livestock; cattle, sheep and deer. To investigate the relevance of these findings we performed a systematic literature review on global C. hyointestinalis epidemiology and used comparative genomics to better understand and classify members of the species...
February 5, 2018: Scientific Reports
Shany Doron, Sarah Melamed, Gal Ofir, Azita Leavitt, Anna Lopatina, Mai Keren, Gil Amitai, Rotem Sorek
The arms race between bacteria and phages led to the development of sophisticated antiphage defense systems, including CRISPR-Cas and restriction-modification systems. Evidence suggests that unknown defense systems are located in "defense islands" in microbial genomes. We comprehensively characterized the bacterial defensive arsenal by examining gene families that are clustered next to known defense genes in prokaryotic genomes. Candidate defense systems were systematically engineered and validated in model bacteria for their antiphage activities...
January 25, 2018: Science
Clara López-Hermoso, Rafael R de la Haba, Cristina Sánchez-Porro, Antonio Ventosa
Ten Gram-strain-negative, facultatively anaerobic, moderately halophilic bacterial strains, designated AL184T, IB560, IB563, IC202, IC317, MA421, ML277, ML318, ML328A and ML331, were isolated from water ponds of five salterns located in Spain. The cells were motile, curved rods and oxidase and catalase positive. All of them grew optimally at 37°C, at pH 7.2-7.4 and in the presence of 7.5% (w/v) NaCl. Based on phylogenetic analyses of the 16S rRNA, the isolates were most closely related to Salinivibrio sharmensis BAGT (99...
December 21, 2017: Systematic and Applied Microbiology
Clémence Plissonneau, Fanny E Hartmann, Daniel Croll
BACKGROUND: Structural variation contributes substantially to polymorphism within species. Chromosomal rearrangements that impact genes can lead to functional variation among individuals and influence the expression of phenotypic traits. Genomes of fungal pathogens show substantial chromosomal polymorphism that can drive virulence evolution on host plants. Assessing the adaptive significance of structural variation is challenging, because most studies rely on inferences based on a single reference genome sequence...
January 11, 2018: BMC Biology
Uri Sela, Chad W Euler, Joel Correa da Rosa, Vincent A Fischetti
A fundamental question in human susceptibility to bacterial infections is to what extent variability is a function of differences in the pathogen species or in individual humans. To focus on the pathogen species, we compared in the same individual the human adaptive T and B cell immune response to multiple strains of two major human pathogens, Staphylococcus aureus and Streptococcus pyogenes. We found wide variability in the acute adaptive immune response induced by various strains of a species, with a unique combination of activation within the two arms of the adaptive response...
January 2018: PLoS Pathogens
Verlaine J Timms, Rebecca Rockett, Nathan L Bachmann, Elena Martinez, Qinning Wang, Sharon C-A Chen, Neisha Jeoffreys, Peter J Howard, Anna Smith, Sheena Adamson, Robin Gilmour, Vicky Sheppeard, Vitali Sintchenko
The city of Sydney, Australia, experienced a persistent outbreak of Legionella pneumophila serogroup 1 (Lp1) pneumonia in 2016. To elucidate the source and guide public health actions the genomes of clinical and environmental Lp1 isolates recovered over 7 weeks were examined. A total of 48 isolates from human cases and cooling towers were sequenced and compared using SNP-based, core-genome MLST and pangenome approaches. All three methods confirmed phylogenetic relatedness between isolates associated with outbreaks in the Central Business District (CBD) in March and May and Suburb 1...
December 15, 2017: Applied and Environmental Microbiology
Jason C Kwong, Eric P F Chow, Kerrie Stevens, Timothy P Stinear, Torsten Seemann, Christopher K Fairley, Marcus Y Chen, Benjamin P Howden
OBJECTIVES: Drug-resistant Neisseria gonorrhoeae are now a global public health threat. Direct transmission of antibiotic-resistant gonococci between individuals has been proposed as a driver for the increased transmission of resistance, but direct evidence of such transmission is limited. Whole-genome sequencing (WGS) has superior resolution to investigate outbreaks and disease transmission compared with traditional molecular typing methods such as multilocus sequence typing (MLST) and N...
December 15, 2017: Sexually Transmitted Infections
C W Knetsch, N Kumar, S C Forster, T R Connor, H P Browne, C Harmanus, I M Sanders, S R Harris, L Turner, T Morris, M Perry, F Miyajima, P Roberts, M Pirmohamed, J G Songer, J S Weese, A Indra, J Corver, M Rupnik, B W Wren, T V Riley, E J Kuijper, T D Lawley
The emergence of Clostridium difficile as a significant human diarrheal pathogen is associated with the production of highly transmissible spores and the acquisition of antimicrobial resistance genes (ARGs) and virulence factors. Unlike the hospital-associated C. difficile RT027 lineage, the community-associated C. difficile RT078 lineage is isolated from both humans and farm animals; however, the geographical population structure and transmission networks remain unknown. Here, we applied whole-genome phylogenetic analysis of 248 C...
March 2018: Journal of Clinical Microbiology
Frauke Beilstein, Matthieu Blanchet, Andrew Vaillant, Camille Sureau
In this study, an in vitro infection model for the hepatitis delta virus (HDV) was used to evaluate the antiviral effects of phosphorothioate nucleic acid polymers (NAPs) and investigate their mechanism of action. The results show that NAPs inhibit HDV infection at concentrations less than 4 μM in cultures of differentiated human hepatoma cells. NAPs were shown to be active at viral entry but inactive postentry on HDV RNA replication. Inhibition was independent of the NAP nucleotide sequence but dependent on both size and amphipathicity of the polymer...
February 15, 2018: Journal of Virology
Bhavna Hurgobin, Agnieszka A Golicz, Philipp E Bayer, Chon-Kit Kenneth Chan, Soodeh Tirnaz, Aria Dolatabadian, Sarah V Schiessl, Birgit Samans, Juan D Montenegro, Isobel A P Parkin, J Chris Pires, Boulos Chalhoub, Graham J King, Rod Snowdon, Jacqueline Batley, David Edwards
Homoeologous exchanges (HEs) have been shown to generate novel gene combinations and phenotypes in a range of polyploid species. Gene presence/absence variation (PAV) is also a major contributor to genetic diversity. In this study, we show that there is an association between these two events, particularly in recent Brassica napus synthetic accessions, and that these represent a novel source of genetic diversity, which can be captured for the improvement of this important crop species. By assembling the pangenome of B...
December 4, 2017: Plant Biotechnology Journal
Andrew Brantley Hall, Moran Yassour, Jenny Sauk, Ashley Garner, Xiaofang Jiang, Timothy Arthur, Georgia K Lagoudas, Tommi Vatanen, Nadine Fornelos, Robin Wilson, Madeline Bertha, Melissa Cohen, John Garber, Hamed Khalili, Dirk Gevers, Ashwin N Ananthakrishnan, Subra Kugathasan, Eric S Lander, Paul Blainey, Hera Vlamakis, Ramnik J Xavier, Curtis Huttenhower
BACKGROUND: Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal tract that is associated with changes in the gut microbiome. Here, we sought to identify strain-specific functional correlates with IBD outcomes. METHODS: We performed metagenomic sequencing of monthly stool samples from 20 IBD patients and 12 controls (266 total samples). These were taxonomically profiled with MetaPhlAn2 and functionally profiled using HUMAnN2...
November 28, 2017: Genome Medicine
Roman Pantůček, Ivo Sedláček, Adéla Indráková, Veronika Vrbovská, Ivana Mašlaňová, Vojtěch Kovařovic, Pavel Švec, Stanislava Králová, Lucie Krištofová, Jana Kekláková, Petr Petráš, Jiří Doškař
Two Gram-stain-positive, coagulase-negative staphylococcal strains were isolated from abiotic sources, stone fragments and sandy soil in James Ross Island, Antarctica. Here we describe properties of novel species of the genus Staphylococcus that has near identical 16S rRNA gene sequence to Staphylococcus saprophyticus However, compared to S. saprophyticus and the next closest relatives, the new species demonstrates considerable phylogenetic distance at whole genome level, average nucleotide identity <85 %, and inferred DNA-DNA hybridization <30%...
October 27, 2017: Applied and Environmental Microbiology
Wei Ding, Franz Baumdicker, Richard A Neher
Horizontal transfer, gene loss, and duplication result in dynamic bacterial genomes shaped by a complex mixture of different modes of evolution. Closely related strains can differ in the presence or absence of many genes, and the total number of distinct genes found in a set of related isolates-the pan-genome-is often many times larger than the genome of individual isolates. We have developed a pipeline that efficiently identifies orthologous gene clusters in the pan-genome. This pipeline is coupled to a powerful yet easy-to-use web-based visualization for interactive exploration of the pan-genome...
October 25, 2017: Nucleic Acids Research
William F Martin
The realization that prokaryotes naturally and frequently disperse genes across steep taxonomic boundaries via lateral gene transfer (LGT) gave wings to the idea that eukaryotes might do the same. Eukaryotes do acquire genes from mitochondria and plastids and they do transfer genes during the process of secondary endosymbiosis, the spread of plastids via eukaryotic algal endosymbionts. From those observations it, however, does not follow that eukaryotes transfer genes either in the same ways as prokaryotes do, or to a quantitatively similar degree...
December 2017: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
Xiaorui Chen, Matthew D Hitchings, José E Mendoza, Virginia Balanza, Paul D Facey, Paul J Dyson, Pablo Bielza, Ricardo Del Sol
Pest control in agriculture employs diverse strategies, among which the use of predatory insects has steadily increased. The use of several species within the genus Orius in pest control is widely spread, particularly in Mediterranean Europe. Commercial mass rearing of predatory insects is costly, and research efforts have concentrated on diet manipulation and selective breeding to reduce costs and improve efficacy. The characterisation and contribution of microbial symbionts to Orius sp. fitness, behaviour, and potential impact on human health has been neglected...
2017: Frontiers in Microbiology
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