The quantitive analysis of sequential development of biofilm spatial structure of P. aeruginosa lasR rhlR mutant tagged with green fluorescence protein

Objective To investigate the effect of quorum-sensing(QS) system on Pseudomonas aeruginosa biofilm formation in vitro.Method In vitro biofilm models of P.aeruginosa wild-type PA01 and lasR rhlR mutant were established on glass slice.Then,the biofilm development of the two strains tagged with SYT09/PI were detected using confocal laser scanning microscopy on day 3.Quantitative parameters describing biofilm spatial structure were acquired after the image information was calculated by Image Structure Analyzer(ISA) software.Result After being cultured for 3 days,the biofilm was mature in the PA01,whereas it was poorly formed in △lasR△rhlR group.The quantitative data from ISA software showed that the thickness of △lasR△rhlR biofilm was(7.36±0.2)μm,while that of PA01 was(21.64±0.57)μm(P0.05).Meanwhile the areal porosity(AP) was(0.902±0.006) and(0.928±0.002),respectively;Average diffusion distance(ADD) and textural entropy(TE) were(1.503±0.029) and(5.706±0.190) in △lasR△rhlR biofilm,while(1.467±0.015) and(5.213±0.111) in PA01 biofilm.AP of △lasR△rhlR biofilm was less than PA01(t=0.335,P0.05),but ADD and TE of △lasR△rhlR biofilms were larger than that of PA01(P0.05).Conclusion △lasR△rhlR obviously affects the formation of biofilm of P.aeruginosa.QS system plays an important role in the formation of P.aeruginosa biofilm.