A Simple Electrochemical System to Evaluate Interactions between Bauhinia monandra Leaf Lectin (BmoLL) and Cratylia mollis Seed Lectin (Cramoll) Immobilized in Nafion Nanopores with Pseudomonas aeruginosa Endophytic Strain

An electrochemical system evaluated the interaction of lectins immobilized in nanopores of Nafion with strains of Pseudomonas aeruginosa. Bauhinia monandra leaf lectin, BmoLL, specific for galactose, interacted with P. aeruginosa strain UFPEDA598, an endophytic bacterium isolated from B. monandra leaves. Cratylia mollis seed lectin, Cramoll, specific for glucose-mannose, did not bind to the endophytic strain, but recognized a pathogenic bacterium of P. aeruginosa, strain UFPEDA-39 (IT2633). BmoLL revealed high recognition of the UFPEDA598 endophytic bacterium strain; the result of this interaction was evidenced by an increase in electrochemical potential and stability in the presence of galactose, the lectin inhibitor, with a binding preference for endophytic membrane carbohydrates. Cramoll did not interact with the endophytic strain, since there was no variation in the electrochemical potential in relation to the control; however, the addition of glucose to the system promoted a lower potential, indicating the lectin preference for the monosaccharide. On the other hand, Cramoll showed high specificity for the membrane carbohydrates of P. aeruginosa strain UFPEDA-39 (IT2633); a decrease in the electrical potential was observed after the interaction, with stability to the glucose-inhibited lectin. We developed a simple, label-free system for recognizing microorganisms in real time. The biosensor clearly distinguished the glycoconjugate surfaces of P. aeruginosa from different environments and can be useful for the selective identification of strains of the same species. The electrochemical detection of lectin interconnections with microorganisms is relevant to unravel structural recognition mechanisms.