We have assembled a non-redundant set of mutants from the library in which a single mutant is chosen to represent a particular non-essential open reading frame(17). An automated selection scheme based on insertion site proximity to the 5' end of a particular open reading frame was used to pick mutants for the PA14NR Set (Mutant Selection Criteria). Version 1.0 of the PA14NR Set consists of approximately 5800 (representing approximately 4600 PA14 genes) mutants arranged in a 96-well format and is available upon request for a fee that reimburses us for out-of-pocket costs. (Request Mutant).

Extensive quality control precautions have been put in place. For instance, each mutant in the PA14NR Set has been colony-purified to insure that cultures derived from the PA14NR Set are free of low levels of cross-contaminants that often plague large libraries. Colony purification also minimizes the size of small colony variant populations (See Figure 2 and reference 11). These PA14 subpopulations arise under certain growth conditions and display altered phenotypes, including enhanced biofilm formation and decreased virulence. Replication of the PA14NR Set must be conducted under specific conditions to minimize overgrowth. A PA14NR Set Lab Manual [pdf], specifying growth conditions and handling techniques is available on this site.