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Doijad, S. P.

Publications and source records attributed to Doijad, S. P..

2 recordsLinked to original sources

Jaeger: an accurate and fast deep-learning tool to detect bacteriophage sequences

Viruses are integral to every biome on Earth, yet we still need a more comprehensive picture of their identity and global distribution. Global metagenomics sequencing efforts revealed the genomic content of tens of thousands of environmental samples, however identifying the viral sequences in these datasets remains challenging due to their vast genomic diversity. Here, we address identifying bacteriophage sequences in unlabeled sequencing data. In a recent benchmarking paper, we observed that existing deep-learning tools show a high true positive rate, but may also produce many false positives when confronted with divergent sequences. To tackle this challenge, we introduce Jaeger, a novel deep-learning method designed specifically for identifying bacteriophage genome fragments. Extensive benchmarking on the IMG/VR database and real-world metagenomes reveals Jaegers consistent high sensitivity (0.87) and precision (0.92). Applying Jaeger to over 16,000 metagenomic assemblies from the MGnify database yielded over five million putative phage contigs. On average, Jaeger is around 20 times faster than the other state-of-the-art methods. Jaeger is available at https://github.com/MGXlab/Jaeger.

bioinformatics↗

A single residue within the MCR-1 protein confers anticipatory resilience

The envelope stress response (ESR) of Gram-negative enteric bacteria senses fluctuations in nutrient availability and environmental changes to avert damage and promote survival. It has a protective role towards antimicrobials but direct interactions between ESR components and antibiotic resistance genes have not been demonstrated. Here we report specific interactions between the two-component conjugative pilus expression (Cpx)RA signal transduction system and the recently described mobile colistin resistance (MCR-1) protein. Purified MCR-1 is specifically cleaved by the serine endoprotease DegP within a structurally conserved periplasmic bridging domain. Cleavage-site mutations in MCR-1 render derivatives either protease-resistant or degradation-susceptible with widely differing consequences for colistin resistance. Transfer of the degradation-susceptible mutant to strains that lack either DegP or its regulator CpxRA restores expression and colistin resistance. MCR-1 production in Escherichia coli induces a Cpx-dependent ESR and imposes growth restriction in strains lacking either DegP or CpxRA, effects that are reversed by transactive expression of DegP. MCR-1 production impairs bacterial motility indicating dissipation of cytoplasmic transmembrane potential. Indeed, growth in media with low pH dramatically increases both MCR-1-dependent phosphoethanolamine (PEA) modification of lipid A as well as colistin-resistance activity. In vitro transferase- and lipid A reconstitution-assays demonstrate that MCR-1 is highly active at acidic pH. Acquiring MCR-1 also renders strains more resistant to antimicrobial peptides. Thus, a conserved motif within MCR-1 induces components of the ESR to confer resilience to stimuili commonly encountered in the environment such as to changes in pH and towards antimicrobial peptides. Excipient allosteric activation of the DegP protease specifically inhibits growth of isolates carrying mcr-1 plasmids indicating that a targeted strategy can lead to the elimination of transferable colistin resistance in Gram-negative bacteria.

microbiology↗