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The Crispr/Cas Adaptive Immune System Of Pseudomonas Aeruginosa Mediates Resistance To Naturally Occurring And Engineered Phages, Kyle C. Cady, Joe Bondy-Denomy, Gary E. Heussler, Alan R. Davidson, George A. O'Toole
The Crispr/Cas Adaptive Immune System Of Pseudomonas Aeruginosa Mediates Resistance To Naturally Occurring And Engineered Phages, Kyle C. Cady, Joe Bondy-Denomy, Gary E. Heussler, Alan R. Davidson, George A. O'Toole
Dartmouth Scholarship
Here we report the isolation of 6 temperate bacteriophages (phages) that are prevented from replicating within the laboratory strain Pseudomonas aeruginosa PA14 by the endogenous CRISPR/Cas system of this microbe. These phages are only the second identified group of naturally occurring phages demonstrated to be blocked for replication by a nonengineered CRISPR/Cas system, and our results provide the first evidence that the P. aeruginosa type I-F CRISPR/Cas system can function in phage resistance. Previous studies have highlighted the importance of the protospacer adjacent motif (PAM) and a proximal 8-nucleotide seed sequence in mediating CRISPR/Cas-based immunity. Through engineering of a protospacer …
Lapg, Required For Modulating Biofilm Formation By Pseudomonas Fluorescens Pf0-1, Is A Calcium-Dependent Protease, Chelsea D. Boyd, Debashree Chatterjee, Holger Sondermann, George A. O'Toole
Lapg, Required For Modulating Biofilm Formation By Pseudomonas Fluorescens Pf0-1, Is A Calcium-Dependent Protease, Chelsea D. Boyd, Debashree Chatterjee, Holger Sondermann, George A. O'Toole
Dartmouth Scholarship
Biofilm formation by Pseudomonas fluorescens Pf0-1 requires the cell surface adhesin LapA. We previously reported that LapG, a periplasmic cysteine protease of P. fluorescens, cleaves the N terminus of LapA, thus releasing this adhesin from the cell surface and resulting in loss of the ability to make a biofilm. The activity of LapG is regulated by the inner membrane-localized cyclic-di-GMP receptor LapD via direct protein-protein interactions. Here we present chelation and metal add-back studies demonstrating that calcium availability regulates biofilm formation by P. fluorescens Pf0-1. The determination that LapG is a calcium-dependent protease, based on in vivo and in vitro …