title: Studying the effect of alginate overproduction on Pseudomonas aeruginosa biofilm by atomic force microscopy.
abstract: Pseudomonas aeruginosa is the most important pathogen in cystic fibrosis patients and forms biofilms in the lung. P. aeruginosa strains isolated from the lungs of the patients have a mucoid phenotype overproducing alginate. The phenotype forms highly structured biofilms which are more resistant to antibiotics than biofilms formed by its nonmucoid phenotype. Conversion to the alginate-overproducing phenotype occurs through a mutation in rpoN gene in the strains. The biofilms formed by the alginate-overproducing phenotype are highly sticky, but their stickiness has not been measured. Herein, the stickiness of biofilms formed by the rpoN mutant was measured by atomic force microscopy (AFM). Confocal laser scanning microscopy showed that the biofilms formed by the slowly-growing rpoN mutant were more structured than those formed by the wild-type strain. AFM analysis indicated that the biofilms formed by the rpoN mutant were stickier than those formed by the wild type strain during the attachment and establishment stages, but the difference in stickiness was greatly reduced during the maturation stage possibly due to the cytosolic contents released from dead cells in the biofilms formed by the wild type. These results suggest that the alginate overproduction greatly affects the physical properties (topography and stickiness) of P. aeruginosa biofilms as well as the physiological properties (cell death and growth) of the bacterial cells inside the biofilms.
authors: Department of Chemistry and Nano Sciences (BK21), Ewha Womans University, Seoul 120-750, Korea.
authors: Jeesun
authors: J
authors: Lim
authors: Yidan
authors: Y
authors: Cui
authors: Yoo Jin
authors: YJ
authors: Oh
authors: Ja Ryeong
authors: JR
authors: Park
authors: William
authors: W
authors: Jo
authors: You-Hee
authors: YH
authors: Cho
authors: Sungsu
authors: S
authors: Park
mesh_terms: D000464:Alginates / Q000378:metabolism*; D018441:Biofilms; D020723:Glucuronic Acid / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D009154:Mutation / Q000502:physiology; D010641:Phenotype; D011550:Pseudomonas aeruginosa / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051877:RNA Polymerase Sigma 54 / Q000235:genetics
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D051877:RNA Polymerase Sigma 54