[Effect of cadmium, zinc, lead and mercury on enzyme activity in Saccharomyces cerevisiae]. / Der Einfluss von Cadmium, Zink, Blei und Quecksilber auf die Enzymaktivität bei Saccharomyces cerevisiae in vivo.

The in vivo influence of cadmium, zinc, lead, and mercury on the activities of intracellular enzymes in Saccharomyces cerevisiae has been studied. Cadmium and lead cause a significant increase of the enzyme activities. Zinc and mercury do not affect the enzyme activities but they intensify considerably the effects of cadmium and lead. A reduction of enzyme activities is found only rarely. Interactions between the heavy metals tested can lead to synergism or to antagonism or rather to an addition of the effects. The findings suggest that under in vivo conditions heavy metals show only an indirect influence on intracellular enzymes.

[Effect of heavy metal interactions on the growth of Saccharomyces cerevisiae]. / Einfluss von Schwermetallinteraktionen auf das Wachstum von Saccharomyces cerevisiae.

The influence of interactions of cadmium, zinc, lead, and mercury on the growth of Saccharomyces cerevisiae has been studied. Generally the experiments resulted in the following findings: Low zinc concentrations reduce the toxicity of cadmium while high zinc concentrations intensify the effects of cadmium. Zinc does not decrease the growth inhibition by mercury. The actions of cadmium and mercury are not changed by lead, but 5 X 10(-4) M lead prevent completely the increase of the growth intensity caused by zinc. Combinations of toxic concentrations of cadmium and mercury show a synergistic lengthening of the lag period, but their cumulative influence on the growth rate is lower than the sum of the corresponding inhibition effects.

[Effect of cadmium, zinc, lead and mercury on the enzyme activity in Saccharomyces cerevisiae in vitro]. / Der Einfluss von Cadmium, Zink, Blei und Quecksilber auf die Enzymaktivität bei Saccharomyces cerevisiae in vitro.

The difference between cadmium, zinc, lead, and mercury in regard of their effects on the activity of the enzymes tested is very slight. Concentrations higher than 10(-5) M reduce significantly the activity of the enzymes, and concentrations of approximately 10(-3) M inhibit it completely. An increase of the activity cannot be detected. The addition of combinations of cadmium, zinc, and lead results in a summing up of the toxic effects, whereas the interaction between mercury and the other three heavy metals shows a cumulative effect, which is appointed nearly completely by the heavy metal more toxic. The findings suggest that under in-vitro conditions there exists a direct interaction between the heavy metals and the enzymes.

[Effects of cadmium, zinc, lead and mercury on the growth and accumulating ability of Saccharomyces cerevisiae, Saccharomycopsis lipolytica, Candida tropicalis, and Candida utilis]. / Der Einfluss von Cadmium, Zink, Blei und Quecksilber auf das Wachstum und das Akkumulationsvermögen von Saccharomyces cerevisiae, Saccharomycopsis lipolytica, Candida tropicalis und Candida utilis.

The effects of cadmium, zinc, lead, and mercury on the growth and the accumulating ability of Saccharomyces cerevisiae, Saccharomycopsis lipolytica, Candida tropicalis, and Candida utilis had been studied. Generally the experiments resulted in the following findings: Very small concentrations of cadmium and mercury already decrease the growth intensity of the yeasts by lengthening the lag period and the doubling time. The cell yield is not reduced. Zinc increases the productivity of Saccharomyces cerevisiae and Saccharomycopsis lipolytica by shortening the lag period. The lead concentrations investigated show no significant influence on the growth. Low pH values intensify the effectiveness of the four heavy metals. The yeasts tested accumulate heavy metals, especially cadmium, to high concentrations and therefore substrates containing heavy metals are only limited suitable for the scp-production with yeasts.