Regulation of Lectin Production by the Human Pathogens Pseudomonas aeruginosa and Chromobacterium violaceum: Effects of Choline, Trehalose, and Ethanol

Insights on Pseudomonas aeruginosa Carbohydrate Binding from Profiles of Cystic Fibrosis Isolates Using Multivalent Fluorescent Glycopolymers Bearing Pendant Monosaccharides

“…The α-galactose moiety binding observed for a subpopulation of the cells in the cultures is consistent with the natural ligand-binding affinity [88,94,112] anticipated for cells presenting surface-associated LecA. Whole Pseudomonas cells lacked binding with the ß-Gal-PAA-Fluor, representing the lesser preferred LecA ligand ß-Gal [112].…”

“…It should also be respected in therapeutics design that, as discussed above, the varied permutations of the condition of the host, as well as the adaptations of the colonizing microbes and the treatments being received, are likely to keep the infectious landscape ever-changing [8,20,43,133]. The P. aeruginosa variability and fluidity in the expression or lack of expression of virulence features and structures are expected to complicate the development of targeted agents [10,11,15,20,24,26,29,36,58,63,88,90,116,117,131,136]. The distinctions and differences in complex mucosal glycoconjugates are anticipated in CF respiratory tracts and are mechanistically important to bacterial binding and/or clearance [9,60,65,67,78,79,81,82].…”

“…As explained for other lectins, the LecA grove may have sites available for making contacts with the other carbohydrates in the chain or branch to improve the apparent affinity for glycoconjugates with terminal ß-galactose [91,108,111,145]. LecA activities were known, from hemagglutination assays and other studies, to be inhibited by α-Gal and, to a lesser degree, by ß-GalNAc [47,60,70,88]. This suggests that, in the current study, LecA might have contributed to the surface binding of both the α-Gal and the ß-GalNAc glycopolymers.…”

“…Unanticipated in the current study was the notable lack of binding of the fucose glycopolymer to any of the whole-cell CF or non-CF Pseudomonas isolates. Fucose glycopolymerbinding would be predicted through LecB [88,90,146]. Soluble LecB has a monosaccharide affinity specific for fucose and mannose and was recently shown to bind the α-mannose side chains of the Psl exopolysaccharide [89].…”

“…As aggregates are known to be more antibiotic-and DNase-tolerant, adjuvant-induced aggregation may contribute to a reduced sensitivity to routine anti-Pseudomonal therapeutics [14,24]. The elaboration of lectins and other adhesive extracellular features are known to vary between P. aeruginosa strains and with environmental growth conditions [10,29,36,56,58,64,70,73,88,90,93,114,115]. LecA and LecB proteins, in vitro, for example, appeared to be the most abundant during the stationary phase [90,93].…”