Investigating yeast cell responses to oestrogen by electrochemical detection

Candida albicans and some other yeast species are known to have an oestrogen binding protein (EBP), which oxidises NAD(P)H to NAD(P)+. 17β-oestradiol, when present, binds to the NAD(P)H oxidation site which leads to an accumulation of NAD(P)H. Our previous research has shown that oestrogens can be quantified using Saccharomyces cerevisiae cells as the detection element and a double mediator electrochemical system to measure NAD(P)H. In a modification to the whole cell method, C. albicans cell lysate and a single hydrophilic mediator was used to quantify 17β-oestradiol. This paper employs the mediated electrochemical systems to investigate the influence of growth phase on EBP production in C. albicans and the response of cells of different ages to different concentrations of oestrogen. A cell not known to possess EBP (Arxula adeninivorans) was also investigated for its response to 17β-oestradiol. As expected, A. adeninivorans did not show a detectable response to 17β-oestradiol, but surprisingly, its catabolism was inhibited.