The Effect of Curcumin on Adenylyl Cyclase Expression in Escherichia Coli

Schimmel/Conrades Science Center Atrium

Curcumin, the main active ingredient in turmeric, is known for having powerful anti-inflammatory and antioxidant effects. Previous studies, including in our own lab, have also shown a strong anti-viral property of curcumin in mammalian cells, limiting the number of virus particles produced during infection. However, recent work from Dr. Jerry Goldstein with Escherichia coli bacteria and T2 bacteriophages (bacterial viruses) have found a pro-viral property of curcumin, with a strong increase of number of virus particles during infection. It is known that increased metabolism in bacteria can yield more virus production during infection. One measurement for increased metabolism is the increased production of cyclic AMP (cAMP), which requires the enzyme adenylyl cyclase (cycA). Here, we tested whether curcumin stimulates increased expression of cycA, in turn, causing more cAMP to be produced. Bacteria were cultured in 20 microgram/mL of curcumin, an optimal dose for increased T2 bacteriophage yield, and RNA was collected at 0h, 1.5h, and 2.5h. Levels of cycA mRNA were measured through the use of quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Several rounds of optimization were needed to detect bacterial mRNA expression through this technique, and it was determined that qRT-PCR on bacterial RNA samples requires PCR products of 400-600 bp in length with correspondingly longer extension times. This is in contrast to the 50-300 bp product sizes typically used in eukaryotic samples. Our initial results indicate that curcumin treatment at 1.5h and 2.5h led to approximately 25% and 10% reduced expression of cycA, respectively, compared to control and normalized to the reference gene DNA gyrase B (gyrB). If these results are confirmed in future experiments, this suggests that increased virus yield in bacteria due to curcumin treatment is not due to increased cellular metabolism.