Methods for assessment of heavy metal toxicity towards fungi and yeasts

Abstract

SynopsisThe analysis of K + release, respiration rates and tests relying on diffusion processes in agar medium have applications for the study and assessment of heavy metal toxicity towards fungi and yeasts. Such techniques have been seldom exploited for this purpose but can provide information not only on toxicity but also on morphological and physiological responses towards heavy metals.

Pb(II) biosorption from hazardous aqueous streams using Gossypium hirsutum (Cotton) waste biomass

“…But these results were not surprising, as in all the biosorbent dosage experiments, percent metal adsorption is inversely related with metal uptake capacity of biosorbent. The decrease in adsorption capacity (q) was observed because higher biosorbent dose caused electrostatic interactions between cells and interference between the binding sites [24]. 100 mg/L for contact time of 24 h. From the same figure it is evident that, smaller the granular size of biosorbent, larger the adsorption capacity (q).…”

Diffusion assays for determination of the effects of pH on the toxicity of heavy metal compounds towards filamentous fungi

“…Both well-diffusion and two-dimensional gradient plates have applications for studies on the effects of external conditions, like pH, on heavy metal toxicity towards filamentous fungi (3,5). The techniques are easy and are economical in terms of time and media, both common drawbacks with agar or broth dilution methods (3).…”

Optimisation of a rapid bioassay for nisin utilising potassium efflux from sensitivePediococcus sp. cells

“…Toxic substances which damage cell membrane integrity also cause the release of K + from cells. Examples are heavy metals (Gadd et al, 1985) and ATPase inhibitors (Borst-Pauwels et aI, 1983). It therefore appeared probable that nisin would also cause K § release in sensitive bacteria which could be used as a rapid bioassay.…”