Aylin Moayedi - Department of Microbiology, Tehran North Branch, Islamic Azad University, Tehran, Iran
Jamileh Nowroozi - Department of Microbiology, Tehran North Branch, Islamic Azad University, Tehran, Iran
Abbas Akhavan Sepahy - Department of Microbiology, Tehran North Branch, Islamic Azad University, Tehran, Iran

Objective(s): Pyocyanin is a blue-greenish redox-active pigment, produced by Pseudomonas aeruginosa, with a wide range of biological and biotechnological applications. Pyocyanin biosynthesis is regulated by the quorum-sensing (QS) system in which the expression of QS genes and QS-controlled virulence genes may be affected by serum as a complex medium. In the current study, effects of adult bovine serum (ABS) and fetal bovine serum (FBS) on the production of pyocyanin were examined in order to develop it. Materials and Methods: The presence of pyocyanin-producing specific genes and proteins in clinical and soil isolates of P. aeruginosa was confirmed using PCR and SDS-PAGE. Isolates were inoculated to media containing different concentrations of complement-active/-inactivated ABS or FBS and pyocyanin concentration was measured by spectrophotometry. Extracted pigment was characterized by using UV-Visible spectrophotometry. Titration of ABS antibodies against studied isolates was performed by the tube agglutination test. Results: Adding ABS to P. aeruginosa culture medium decreased pyocyanin production compared to the control, while its production increased in FBS-containing media (۱۱۳.۲۱±۲.۵۸۱ vs. ۵۵.۲۶±۰.۸۲۷ μg.ml-۱ and ۱۲۶.۸۰±۲.۰۳۶ vs. ۳۰.۵۶±۰.۳۸۲ μg.ml-۱ of C۱۱ and E۸ pyocyanin concentration in the presence of ۱۰% FBS vs. control, respectively). Conclusion: In this study, due to the presence of inhibitors such as complement proteins and antibodies in ABS samples, the use of FBS devoid of antibodies was effective to increase pyocyanin production in studied isolates.

Adult bovine serum, Fetal bovine serum, PhzM, Pseudomonas aeruginosa, Pyocyanin