Cas9-assisted biological containment of a genetically engineered human commensal bacterium and genetic elements.

Sophisticated gene circuits built by synthetic biology can enable bacteria to sense their environment and respond predictably. Engineered biosensing bacteria outfitted with such circuits can potentially probe the human gut microbiome to prevent, diagnose, or treat disease. To provide robust biocontainment for engineered bacteria, we devised a Cas9-assisted auxotrophic biocontainment system combining thymidine auxotrophy, an Engineered Riboregulator (ER) for controlled gene expression, and a CRISPR Device (CD).

Effect of Gravity on Bacterial Adhesion to Heterogeneous Surfaces.

Bacterial adhesion is the first step in the formation of surface biofilms. The number of bacteria that bind to a surface from the solution depends on how many bacteria can reach the surface (bacterial transport) and the strength of interactions between bacterial adhesins and surface receptors (adhesivity). By using microfluidic channels and video microscopy as well as computational simulations, we investigated how the interplay between bacterial transport and adhesivity affects the number of the common human pathogen that bind to heterogeneous surfaces with different receptor densities.

Host happy hour: Phage cocktail targets IBD-associated microbes.

Bacteriophage therapy is a promising strategy to treat bacterial infections and sculpt the microbiome. In a recent Cell paper, Federici et al. (2022) demonstrate that a Klebsiella pneumoniae phage cocktail can specifically remove pathobionts from the mouse gut.