Volume 4 Issue 8, August 2019

Host cells assemble linear ubiquitin chains to activate immune signalling during bacterial infection. A new study reveals that Legionella pneumophila — the causative agent of Legionnaires’ disease — produces an enzyme that specifically disassembles these linear ubiquitin modifications to restrict immune responses.

The finding that the two cell wall elongation systems of Bacillus subtilis have opposite effects on cell diameter and on the amount of oriented material along the sidewalls elucidates the long-standing question of how cell width is controlled in rod-shaped bacteria.

Complementary genomic frameworks for taxonomic classification of viruses infecting bacteria and archaea reveal evolutionary drivers, mosaicism and perspective on the genetic diversity of the tiniest, most abundant biological entities on Earth.

There is increasing evidence of direct and/or indirect interactions between bacteria and viruses. Two new studies shed light on the mechanisms underlying these interactions with implications not only for our understanding of microbial pathogenesis, but also for vaccine design.

This Review summarizes mathematical modelling approaches that can be applied to microbiome datasets, providing insights into microbial dynamics and interactions in this complex system.

The authors report the development of a Madin-Darby canine kidney (MDCK) cell line that is more suitable than conventional MDCK or human virus receptor-overexpressing cells for the isolation and propagation of human influenza viruses without cell culture-adaptive mutations.

A combination of microfluidic devices, transcriptomic analyses and reporter strains shows that Pseudomonas aeruginosa modulates gene expression in response to shear flow. This process, termed rheosensing, does not require known surface sensors and is regulated by the alternative sigma factor FroR.

Legionella pneumophila effector RavD is a deubiquitinase with specificity for linear ubiquitin that inhibits host inflammatory signalling during infection.

The width of rod bacteria depends on the balance between the activities of the Rod complex and aPBPs: the Rod complex reduces cell diameter, whereas aPBPs increase it.

Phylogenetic analysis based on a concatenated set of 77 single-copy marker genes enabled the classification of tailed double-stranded DNA viruses from large datasets, and was reproducible across software and models, providing a framework that could be applied to other viruses.

Co-administration of a whole-inactivated influenza virus (IAV) vaccine (γ-Flu) with a whole-inactivated Streptococcus pneumoniae vaccine (γ-PN) enhances IAV-specific immune responses due to the ability of γ-PN to directly interact with γ-Flu, thus increasing viral uptake by macrophages.

Direct interaction of influenza virus with Gram-positive and Gram-negative bacterial pathogens of the respiratory tract results in increased bacterial adherence to respiratory epithelial cells in culture and in higher bacterial burdens in vivo.

Occurrence modelling of Bacillus anthracis defines global human and animal risk of anthrax infection.

The GTPase MglA, its cognate GTPase activating protein (GAP) MglB and RomR are known to regulate gliding motility in Myxococcus xanthus. There are no known cognate guanine nucleotide exchange factors (GEFs) for MglA. Here, RomX is identified as a binding partner of RomR, and their complex serves as an MglA GEF.

Using metagenomics and proteomics on Mediterranean grassland soil samples resulted in the recovery of 793 metagenome-assembled genomes and provided insights into microbial activity in this environment, and how this changes with soil depth and exposure to extended rainfall.

SEDS family peptidoglycan transglycosylases, RodA and FtsW, in Staphylococcus aureus pair with the cognate transpeptidases PBP3 and PBP1 to mediate sidewall elongation and septal peptidoglycan incorporation, respectively, and maintain coccoid morphology.

Mycobacterium tuberculosis secreted protein MPT53 mediates the activation of TAK1 and induces the host immune inflammatory response.

Leukotriene B₄ signalling contributes to disease tolerance to influenza virus infection by stimulating the production of interferon-α (IFN-α) by interstitial macrophages. IFN-α, in turn, suppresses in situ inflammatory, monocyte-derived macrophage proliferation and mitigates lung immunopathology.

The electron cryo-microscopy structure of Sulfolobus islandicus pili enabled the identification of SiL_2606 as the main pilin in these filaments and revealed that the pili are glycosylated, which probably explains how these structures remain soluble and stable even when cells grow at pH 3 and 80 °C.

VacA promotes Helicobacter pylori intracellular localization and persistence in the face of antibiotics. Activation of the lysosomal TRPML1 calcium channel reverses VacA toxicity and promotes bacterial clearance during drug treatment.