Expanding the Phage Galaxy: Isolation and Characterization of Five Novel Siphoviruses Ankus, Byblos, DekoNeimoidia, Mandalore, and Naboo.

Background: Key features of the actinobacterial genus are multicellular, filamentous growth, and production of a broad portfolio of bioactive molecules. These characteristics appear to play an important role in phage-host interactions and are modulated by phages during infection. To accelerate research of such interactions and the investigation of novel immune systems in multicellular bacteria, phage isolation, sequencing, and characterization are needed.

development is involved in the efficient containment of viral infections.

The formation of plaques represents the hallmark of phage infection visualizing the clearance of the bacterial lawn in structured environments. In this study, we have addressed the impact of cellular development on phage infection in undergoing a complex developmental life cycle. Analysis of plaque dynamics revealed, after a period of plaque size enlargement, a significant regrowth of transiently phage-resistant mycelium into the lysis zone.

Bacterial multicellular behavior in antiviral defense.

Multicellular behavior benefits seemingly simple organisms such as bacteria, by improving nutrient uptake, resistance to stresses, or by providing advantages in predatory interactions. Several recent studies have shown that this also extends to the defense against bacteriophages, which are omnipresent in almost all habitats. In this review, we summarize strategies conferring protection against phage infection at the multicellular level, covering secretion of small antiphage molecules or membrane vesicles, the role of quorum sensing in phage defense, the development of transient phage resistance, and the impact of biofilm components and architecture.

Systematic analysis of prophage elements in actinobacterial genomes reveals a remarkable phylogenetic diversity.

Actinobacteria represent one of the largest bacterial phyla harboring many species of high medical, biotechnological and ecological relevance. Prophage elements are major contributors to bacterial genome diversity and were shown to significantly shape bacterial fitness and host-microbe interactions. In this study, we performed a systematic analysis of prophage elements in 2406 complete actinobacterial genomes.

Aminoglycoside Antibiotics Inhibit Phage Infection by Blocking an Early Step of the Infection Cycle.

In response to viral predation, bacteria have evolved a wide range of defense mechanisms, which rely mostly on proteins acting at the cellular level. Here, we show that aminoglycosides, a well-known class of antibiotics produced by , are potent inhibitors of phage infection in widely divergent bacterial hosts. We demonstrate that aminoglycosides block an early step of the viral life cycle, prior to genome replication.

Phylogenetic Distribution of WhiB- and Lsr2-Type Regulators in Actinobacteriophage Genomes.

Viruses that infect different actinobacterial host species are known as actinobacteriophages. They are composed of highly divergent and mosaic genomes due to frequent gene exchange between their bacterial hosts and related viral species. This is also reflected by the adaptive incorporation of host transcription factors (TFs) into phage regulatory networks.