Anti-viral defence by an mRNA ADP-ribosyltransferase that blocks translation.

Host-pathogen conflicts are crucibles of molecular innovation. Selection for immunity to pathogens has driven the evolution of sophisticated immunity mechanisms throughout biology, including in bacterial defence against bacteriophages. Here we characterize the widely distributed anti-phage defence system CmdTAC, which provides robust defence against infection by the T-even family of phages.

A bacterial immunity protein directly senses two disparate phage proteins.

Eukaryotic innate immune systems use pattern recognition receptors to sense infection by detecting pathogen-associated molecular patterns, which then triggers an immune response. Bacteria have similarly evolved immunity proteins that sense certain components of their viral predators, known as bacteriophages. Although different immunity proteins can recognize different phage-encoded triggers, individual bacterial immunity proteins have been found to sense only a single trigger during infection, suggesting a one-to-one relationship between bacterial pattern recognition receptors and their ligands.

New onset diabetic ketoacidosis in a renal transplant recipient.

Post-transplant diabetes mellitus (PTDM) is a well-known solid organ transplant complication, which can be related to immunosuppressants, particularly tacrolimus. We report an unusual presentation of PTDM with diabetic ketoacidosis (DKA). This is unique as PTDM typically resembles Type 2 DM, whereas DKA is associated with Type 1 DM and has rarely been reported as a complication of tacrolimus.

Principles of bacterial innate immunity against viruses.

All organisms must defend themselves against viral predators. This includes bacteria, which harbor immunity factors such as restriction-modification systems and CRISPR-Cas systems. More recently, a plethora of additional defense systems have been identified, revealing a richer, more sophisticated immune system than previously appreciated.

Mechanism of phage sensing and restriction by toxin-antitoxin-chaperone systems.

Toxin-antitoxins (TAs) are prokaryotic two-gene systems composed of a toxin neutralized by an antitoxin. Toxin-antitoxin-chaperone (TAC) systems additionally include a SecB-like chaperone that stabilizes the antitoxin by recognizing its chaperone addiction (ChAD) element. TACs mediate antiphage defense, but the mechanisms of viral sensing and restriction are unexplored.