Volume 3 Issue 4, April 2018

Metagenomic sequencing, bioinformatic analysis and heterologous expression of an orphan biosynthetic gene cluster widely found in the environment led to the discovery and structural characterization of a novel group of calcium-dependent antibiotics hidden in plain sight.

Bacteria can compete in the environment using antibacterial type VI secretion systems. A recent study reveals that the simultaneous deployment of an arsenal of different toxins promotes both synergy between those toxins and an optimized answer in the face of inconstant environments.

The coupling of root nutrient exudation by plants with microbial nutrient utilization preferences helps drive the assembly of rhizosphere microbiomes, enabling the use of metabolite interaction traits to engineer favourable microbial communities on roots.

Human cytomegalovirus (HCMV) infects pluripotent haematopoietic progenitor cells, yet it is latent in monocyte/myeloid-lineage cells. A new study reveals that HCMV achieves this by actively reprogramming the infected progenitor cell into a unique monocyte subset, enabling the successful lifelong persistence of HCMV in its host.

The TRiC chaperonin has been identified as a crucial player in the assembly of reovirus capsids by folding the σ3 outer-capsid protein into its native conformation. These findings provide a functional understanding of TRiC in virus replication and a rationale for the development of TRiC inhibitors as broad-spectrum anti-viral agents.

G-protein-coupled receptors (GPCRs) enable fungi to sense and respond to their environment. The structure and function of fungal GPCRs are discussed, as well as their potential as targets for antifungal drug development.

Analysis of secondary metabolite biosynthesis clusters from diverse soil samples identifies a distinct class of calcium-dependent antibiotics—the malacidins—that bind lipid II and are active against multidrug-resistant Gram-positive pathogens.

Nuclease-mediated genome editing in bacteria has been limited by toxicity problems linked to DNA cleavage. The use of cytidine deaminase fused to a nuclease-deficient Cas9 bypasses some of these problems, enabling modification of multiple loci simultaneously.

Identification of functional dsyB gene homologues for dimethylsulfoniopropionate production in eukaryotic phytoplankton allows estimation of the relative contributions of eukaryotes and prokaryotes to the global pool, and indicates that this enzyme originated in bacteria.

The activity of effectors transported by the type VI secretion system of Pseudomonas aeruginosa varies under different environmental conditions and some effectors act synergistically, which elucidates why some bacteria carry multiple toxins with distinct activities.

To exit from infected red blood cells, malaria parasites rely on the sequential action of different proteases, such as SUB1 and SERA6, in a process that culminates with the disassembly of the host cell’s cytoskeleton and rupture of the cell membrane.

Combining genome-scale metabolic models of human-associated bacteria with the relative abundance of different bacteria in a community, as measured by metagenomics, allows distinct metabolomes to be inferred that are consistent with experimental data.

Like phages, archaeal viruses also encode anti-CRISPR proteins (Acrs). These include AcrID1 from the lytic rudivirus SIRV3, which interacts with the Cas10d protein of Sulfolobus islandicus. AcrID1 homologues are present in many archaeal viral families.

Using comparative genomics and exometabolomics, the authors characterize the chemical composition of plant root exudates and show that this chemical succession is a likely driver of microbial community assembly in the rhizosphere.

A screen for host factors involved in late steps of the reovirus life cycle identifies the TRiC chaperonin as essential for outer-capsid protein folding, and thus for incorporation onto progeny virions, assembly and virus production.

A human challenge trial with Campylobacter jejuni uncovers transcriptional and genomic changes during infection, highlighting pathogen factors associated with acute and persistent infection.

Human haematopoietic progenitor cells are shown to be targets of human cytomegalovirus infection, which reprogrammes them into long-lived, highly immunosuppressive monocytes, initiating the establishment of latency through the STAT3–iNOS–NO axis.

Here the authors have characterized the growth of 96 human gut bacteria on a range of defined media, providing valuable insights into their metabolic capabilities and unique media for future studies.