Volume 3 Issue 11, November 2018

A powerful in vivo biotinylation approach identifies TagA as a binding partner of TssA, a central regulator of the assembly of the type VI secretion system (T6SS). TagA terminates assembly of the T6SS tail and tethers it to the membrane, acting as a crossbow latch that allows for efficient firing.

Protein translocation across bacterial membranes can take many routes through dedicated transport machines. A new study finds that Salmonella Typhi utilizes a distinct pathway to translocate typhoid toxin across the peptidoglycan layer and prime the bacterium for host intoxication.

The discovery of CD153 as a novel driver of T-cell-mediated host defence against Mycobacterium tuberculosis infection advances our understanding of the requirements for protective immunity. Future investigation of CD153 as a potential correlate of tuberculosis immunity could open new avenues for vaccine design.

A key step of the antiviral immune response is detection of the viral intruder. Infection with highly pathogenic strains of influenza virus is now shown to produce short aberrant viral RNAs that potently trigger activation of innate immunity.

CD153 expression by CD4 T cells is required for control of pulmonary Mycobacterium tuberculosis infection.

The conditional overexpression of the transcription factor AP2-G in Plasmodium berghei enables the large-scale conversion of parasite populations into gametocytes, facilitating analysis of the sexual commitment stage of the parasite life cycle.

Flavivirus replication at the endoplasmic reticulum (ER) is targeted by the interferon response through blocking of the formation of virus-induced ER membrane invaginations by the interferon-stimulated gene IFI6, encoding an ER-localized integral membrane effector.

In a rodent malaria model, antibodies against the CSP protein that coats sporozoites lead to Plasmodium yoelii killing in the skin in a process that involves stripping off the CSP coat, rendering parasites susceptible to pore-forming-like proteins.

Aberrant mini viral RNAs, which are produced by erroneous RNA polymerase activity during the replication of the viral RNA genome, act as the main agonists of RIG-I during influenza virus infection.

The secretion of Salmonella Typhi typhoid toxin requires translocation across the peptidoglycan layer through the action of a ld-transpeptidase. Subsequent outer membrane perturbation fully releases toxin for host cell intoxication.

Here the authors show that the human gut microbiome can recover after a clinically relevant, broad-spectrum antibiotic treatment and characterization of the resistome indicates that antibiotic resistance genes can impact the recovery process.

Crystal structures of the AimR from SPβ phage in the apo form and the arbitrium peptide-bound form provide a structural basis for peptide recognition in the phage lysis–lysogeny decision communication system.

A combination of proteomics, metagenome-assembled genomes and heterologous gene expression experiments reveals a trophic system for carbon utilization in the moose rumen microbiome and provides insights into phage dynamics in this ecosystem.

The phage phi3T peptide SAIRGA directs the lysis–lysogeny decision by modulating conformational changes in phAimR, whereas the SPbeta peptide GMPRGA regulates the lysis–lysogeny pathway by stabilizing spAimR in the dimeric state.

Using millimetre-scale replicate granules from an enhanced biological phosphorus removal reactor, the authors observe strain-level variability providing insights into the intrinsic drivers of microbial assembly at relevant spatial scales.

The adaptation of APEX2-dependent proximity biotinylation for use in bacteria enables the identification of binding partners of TssA, which controls T6SS sheath assembly. This approach identifies TagA as a TssA partner that stops sheath polymerization and clamps the extended sheath to the membrane.

Here the authors characterize two polysaccharide utilization loci and provide a model for arabinogalactan degradation by Bacteroides species in the gut microbiome, and show that the cellular location of specific enzymes determines keystone activity.