Arsenic stressed yeast
Posted: 11 Nov 2014, 15:20
Investigation of Arsenic-Stressed Yeast (Saccharomyces cerevisiae) as a Bioassay in Homeopathic Basic Research
Tim Jäger, Claudia Scherr, Ursula Wolf, Meinhard Simon, Peter Heusser, and Stephan Baumgartner
This study investigated the response of arsenic-stressed yeast (Saccharomyces
cerevisiae) towards homeopathically potentized Arsenicum album, a duckweed nosode,
and gibberellic acid. The three test substances were applied in five potency levels (17x,
18x, 24x, 28x, 30x) and compared to controls (unsuccussed and succussed water) with
respect to influencing specific growth parameters. Five independent experiments were
evaluated for each test substance. Additionally, five water control experiments were
analyzed to investigate the stability of the experimental setup (systematic negative
control experiments). All experiments were randomized and blinded. Yeast grew in
microplates over a period of 38 h in either potentized substances or water controls with
250 mg/l arsenic(V) added over the entire cultivation period. Yeast’s growth kinetics
(slope, Et50, and yield) were measured photometrically. The test system exhibited a low
coefficient of variation (slope 1.2%, Et50 0.3%, yield 2.7%). Succussed water did not
induce any significant differences compared to unsuccussed water. Data from the
control and treatment groups were both pooled to increase statistical power. In this
study with yeast, no significant effects were found for any outcome parameter or any
homeopathic treatment. Since in parallel experiments arsenic-stressed duckweed
showed highly significant effects after application of potentized Arsenicum album and
duckweed nosode preparations from the same batch as used in the present study, some
specific properties of this experimental setup with yeast must be responsible for the
lacking response.
KEYWORDS: Lemna gibba, duckweed, Saccharomyces cerevisiae, yeast, homeopathy,
arsenic, Arsenicum album, nosode, gibberellic acid
Tim Jäger, Claudia Scherr, Ursula Wolf, Meinhard Simon, Peter Heusser, and Stephan Baumgartner
This study investigated the response of arsenic-stressed yeast (Saccharomyces
cerevisiae) towards homeopathically potentized Arsenicum album, a duckweed nosode,
and gibberellic acid. The three test substances were applied in five potency levels (17x,
18x, 24x, 28x, 30x) and compared to controls (unsuccussed and succussed water) with
respect to influencing specific growth parameters. Five independent experiments were
evaluated for each test substance. Additionally, five water control experiments were
analyzed to investigate the stability of the experimental setup (systematic negative
control experiments). All experiments were randomized and blinded. Yeast grew in
microplates over a period of 38 h in either potentized substances or water controls with
250 mg/l arsenic(V) added over the entire cultivation period. Yeast’s growth kinetics
(slope, Et50, and yield) were measured photometrically. The test system exhibited a low
coefficient of variation (slope 1.2%, Et50 0.3%, yield 2.7%). Succussed water did not
induce any significant differences compared to unsuccussed water. Data from the
control and treatment groups were both pooled to increase statistical power. In this
study with yeast, no significant effects were found for any outcome parameter or any
homeopathic treatment. Since in parallel experiments arsenic-stressed duckweed
showed highly significant effects after application of potentized Arsenicum album and
duckweed nosode preparations from the same batch as used in the present study, some
specific properties of this experimental setup with yeast must be responsible for the
lacking response.
KEYWORDS: Lemna gibba, duckweed, Saccharomyces cerevisiae, yeast, homeopathy,
arsenic, Arsenicum album, nosode, gibberellic acid