An Inside Job: Prophages as Accomplices To Release Therapeutic Proteins
Microbial therapeutics hold the potential to treat disease in human medicine and agriculture. So far, the microbial secretory pathway has exclusively been used to secrete recombinant proteins. Alexander et al. (e02335-18) developed a novel approach to deliver therapeutics. The lysogen Lactobacillus reuteri was engineered to intracellularly accumulate recombinant protein. Prophage induction lysed L. reuteri and consequently released the recombinant protein. Since native prophages lyse L. reuteri in the gut, this platform can be used to deliver therapeutics locally. The abundance of lysogenic phages in the gut suggests that their approach may apply to other gut microbes.
Discovery of a Novel Protein Kinase C Inhibitor Specific to Filamentous Fungi
The repeated use of fungicides induces the emergence of resistant strains; consequently, new antifungal agents are always required. Improved screening efficiency would facilitate the exploration of new inhibitors. Sugahara and colleagues (e02923-18) demonstrated that a novel compound, Z-705, which they identified by in silico screening, specifically inhibits protein kinase C activity in filamentous fungi and interferes with the signaling system involved in the virulence of rice blast fungus. This work provides a new model for the development of antifungal agents.
Novel Pseudomonas Alkaloids Mediate Interactions in a Microbiome Model System
Plants select and maintain rhizosphere communities that enhance their growth and protect them from pathogens. To understand these plant microbiomes, the hitchhikers of the rhizosphere (THOR) model community system has been developed and is comprised of representative members of the rhizosphere. Lozano et al. (e03058-18) report a novel and widespread gene cluster in several Pseudomonas spp. that is necessary for the production of a novel family of tetrahydropyridine alkaloids, koreenceine A to D. These are structural analogs of plant alkaloids that mediate the competition between two members of THOR, Pseudomonas koreensis and Flavobacterium johnsoniae, two common rhizosphere inhabitants.
Recovery of Genomes Belonging to the Globally Distributed, Yet-Uncultured Bacterial Phylum LCP-89
Recent advances have enabled the recovery of genomes belonging to yet-uncultured microbial lineages directly from environmental samples. Youssef et al. (e00110-19) recovered genomes belonging to the uncultured bacterial phylum LCP-89 from a range of terrestrial and marine habitats. Detailed analysis identified a cell wall that lacks peptidoglycan and the possession of an intracellular microcompartment for sequestering toxic metabolic intermediates. Predicted metabolic capabilities include degradation of a wide range of sugars, as well as anaerobic respiratory capacities and fermentative capacities. Such characteristics clearly differentiate members of this phylum from those belonging to neighboring phyla within the broader FCB superphylum.
Highly Transmissible Influenza Viruses Exhibit Enhanced Stability in an Aerosol State
Novel influenza viruses that easily spread through the air pose a threat to humans, and understanding the viral traits that facilitate this capability is a critical component of pandemic preparedness. Pulit-Penaloza et al. (e00210-19) selected a panel of H1 subtype influenza viruses with diverse transmission profiles and compared the ratios of viral RNA to infectious virus maintained in aerosols over time to determine the stability of each virus while airborne. Influenza viruses that transmit efficiently through the air displayed enhanced stability in aerosols compared to less-transmissible strains. This study provides a framework for mechanistic evaluations of emerging influenza viruses that threaten public health.
- Copyright © 2019 American Society for Microbiology.