Mohammad Hajjartabar, Nasser Ghaemi, Nasrin Moazzami, Mahshid Faghlhi-Shirazi,
Volume 11, Issue 3 (11-1997)
Abstract
Pseudomonas aeruginosa EF2, ATCC 9027 and ATCC 19660 were grown
in a continuous culture under Tween 80 (polyoxyethylene sorbitan monooleate)
limitation and optimum conditions (pH 6.5, 37°C at dilution rate of 0.05/h).
Culture supernatants were carefully removed and stored at -20°C. To purify the
lipases, the culture supernatant was reduced in volume to approximately 10 mL by
an ultrafiltration unit. Excess salts were removed and extracellular lipase was
purified. Biochemical characterization and SDS polyacrylamide gel electrophoresis
suggested that lipase particles consisted of protein and carbohydrate-including
lipopolysaccharide-with the major enzyme activity being lipase. Lipase activity
was measured as the rate of standard olive oil (predominantly triolein) hydrolysis.
Characterization of the purified extracellular lipases was then investigated by
hydrolysis activity, interesterification reactions and effect on the chemotaxis and
chemiluminescence reactions on human peripheral blood neutrophils and
monocytes. It was shown that lipase from the EF2 strain was the most effective
enzyme used and monocytes were much more sensitive to lipases than neutrophils.
Since monocytes are one of the most important cells of the host defence system,
lipase activity of Pseudomonas aeruginosa may contribute to the pathogenesis of
infections caused by this Gram-negative bacterium.
