Center for Biofilm Engineering
Abstract:
"Spatial Physiological Heterogeneity in Pseudomonas aeruginosa Biofilm is
Determined by Oxygen Availability"
98-020 The role of oxygen availability in determining the local physiological
activity of Pseudomonas aeruginosa growing in biofilms was investigated.
Biofilms grown in an ambient-air environment expressed approximately 1/15th the alkaline
phosphatase specific activity of planktonic bacteria subjected to the same phosphate
limitation treatment. Biofilms grown in a gaseous environment of pure oxygen
exhibited 1.9 times the amount of alkaline phosphatase specific activity of air-grown
biofilms, whereas biofilms grown in an environment in which the air was replaced with pure
nitrogen prior to the inducing treatment did not develop alkaline phosphatase
activity. Frozen cross sections of biofilms stained for alkaline phosphatase
activity with a fluorogenic stain demonstrated that alkaline phosphatase activity was
concentrated in distinct bands adjacent to the gaseous interfaces. These bands were
approximately 30 µm thick with biofilms grown in air, 2 µm thick with biofilms grown in
pure nitrogen, and 46 µm thick with biofilms grown in pure oxygen. Overall
biofilm thickness ranged from approximately 117 µm to approximately 151 µm.
Measurements with an oxygen microelectrode indicated that oxygen was depleted locally
within the biofilm and that the oxygen-replete zone was of a dimension similar to that of
the biologically active zone, as indicated by alkaline phosphatase induction. These
experiments revealed marked spatial physiological heterogeneity within P. aeruginosa
biofilms in which active protein synthesis was restricted by oxygen availability to the
upper 30 µm of the biofilm. Such physiological heterogeneity has implications for
microbial ecology and for understanding the reduced susceptibilities of biofilms to
antimicrobial agents.
Xu, K.D., P.S. Stewart, F. Xia, C-T. Huang, and G.A. McFeters, "Spatial
Physiological Heterogeneity in Pseudomonas aeruginosa Biofilm is Determined by
Oxygen Availability," Appl. Environ. Microbiol., 64(10):4035-4039 (1998).
|
sign take you to sites with
content for which the CBE is not responsible.