Fig. 2 | Scientific Reports

Fig. 2

From: An acyl-homoserine lactone acylase found in Stenotrophomonas maltophilia exhibits both quorum quenching activity and the ability to degrade penicillin antibiotics

Fig. 2

In vivo AHL-degrading activity in S. maltophilia is dependent on Smlt1522. In all bioassays shown, the blue halo in the agar plates indicates AHL detection by the biosensor strain A. tumefaciens KYC55. In each experiment, 20 µL of culture supernatants from the indicated strains were previously incubated with the specified AHLs for 24 h and spotted on the bioassay plate (indicated with an x). (a) Diameter of the AHL detection halos, comparing the wild-type S. maltophilia K279a strain with a smlt1522-deficient strain, and a sterile control which involved incubating the medium with AHLs without any microorganisms, thus no degradation was expected. This demonstrates that the wild-type strain can degrade AHLs, while the smlt1522 mutant completely loses this activity. Tukey’s multiple-comparison test (two-way ANOVA) was used to determine the significance of the data between groups (***, p < 0.001). (b) Molecular structure of the tested AHLs (N-octanoyl-HSL, C8-HSL; N-(3-Oxooctanoyl)-HSL, 3OC8-HSL; N-decanoyl-HSL, C10-HSL). (c) AHL-degrading activity in the presence of C8-HSL, showing that complementing the smlt1522 mutation achieves total degradation of the present AHLs. (d) Bioassays showing how E. coli DH5α acquires the capability to degrade AHLs when Smlt1522 is heterologously expressed.

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