ASSESSMENT OF MOLECULAR-SIEVING ACROSS BACTERIAL OUTER-MEMBRANE OF PSEUDOMONAS

The role of the permeability barrier of the outer membrane of Pseudomo nas was re-evaluated based on the physical theory of molecular sieving in view of its intrinsic antibiotic resistance. We developed a set of analytical procedures based on parametric and non-parametric statisti cal tests to evaluate, validate and adopt the better among a set of co mpeting non-linear models of diffusion. The molecular mass dependence of uptake of non-electrolytes in bacteria yielded a quantitative measu re to distinguish between sieving mechanisms and specific uptake/efflu x mechanisms. The experimental data, supported by the physical model o f DEAE-Sephadex and various analytical models and extensive simulation of the errors, both in measurement and models, yielded evidence consi stent with the relaxation of the outer membrane matrix barrier in Pseu domonas.