Oxo c14 hsl

Sixty millimolar stock solution of oxo-C14-HSL (Sigma-Aldrich) was prepared by dissolving the molecule in acetone. Ten-day-old barley or wheat plants cultivated on 1/10 PNM medium under sterile conditions were treated with oxo-C14-HSL at final concentration of 6 μM. All experiments were performed with the solvent control acetone.

The clinical S. pyogenes isolates S165 (emm6) and S291 (emm1) are blood isolates from patients with severe invasive streptococcal disease41 (link). The strain Agrobacterium tumefaciens NTL4 (pZLR4) used in AHL bioassays was a kind gift from Prof. Stephen Farrand at the University of Illinois, USA. S. pyogenes was grown on GC agar (Acumedia; Lansing, MI, USA). Liquid cultures of S. pyogenes were grown in Todd Hewitt Broth (THB, Acumedia) at 37 °C and 5% CO₂. A. tumefaciens NTL4 (pZLR4) was grown on Luria Agar (Acumedia) with 30 μg/mL of gentamicin at 28 °C. The AHLs (Sigma-Aldrich) oxo-C6-HSL, oxo-C10-HSL, oxo-C12-HSL, and oxo-C14-HSL were added at varying concentration to the THB. Pseudomonas aeruginosa PA01 was a kind gift from Dr. Klaus Udekwu at the Stockholm University, Sweden. The genome sequence of strain S. pyogenes MGAS 10394 from the NCBI database was used for reference in construction of the primers employed in this study.