Clear and present danger? The use of a yeast biosensor to monitor changes in the toxicity of industrial effluents subjected to oxidative colour removal treatments

Abstract

Discharges of coloured effluents into surface waters provide conspicuous evidence of the impact of industry on the environment. The textile industry is an obvious candidate for sources of such discharges. Conventional treatment methods appear to alleviate this situation by removing colour, however the affect on toxicity is less obvious. The objective of this study was to examine the changes in effluent toxicity during the course of two alternative wastewater treatment methods, ozonation and electrochemical oxidation, using a novel toxicity biosensor, GreenScreen EM. The biosensor is capable of measuring both general acute toxicity (cytotoxicity), and more specifically genotoxicity, that is damage to a cell's DNA structure, replication or distribution, caused by substances that may be mutagenic and/or carcinogenic. The biosensor utilises a modified strain of the brewers yeast Saccharomyces cerevisiae, incorporating a gene encoding green fluorescent protein (GFP) linked to the inducible promoter of the DNA damage responsive RAD54 gene. Upon exposure to a genotoxin, the production of GFP is up-regulated in parallel with RAD54, and the resulting cellular fluorescence provides a measure of genotoxicity. Acute toxicity is simultaneously determined by monitoring relative total growth of the cell culture during incubation. The results presented in this paper show that a reduction in colouration does not necessarily correspond to a reduction in effluent toxicity.

Yeasts from Macrobrachium amazonicum: a focus on antifungal susceptibility and virulence factors of Candida spp.

“…Catu Lake is a freshwater source that has been used for human consumption and supply, animal consumption, agriculture, industries and leisure activities. Considering that industrial wastes and pollutants are reported as causes of mutagenesis in yeasts (Keenan et al , 2007) and that the occurrence of gene mutation (Feng et al , 2010) may result in antifungal resistance, we believe that the resistance phenomenon observed in these Candida strains is related to anthropic activities developed in the studied area, such as pollution with industrial, agricultural and farming wastes.…”

Expression of GFP using Pichia pastoris vectors with zeocin or G‐418 sulphate as the primary selectable marker

“…GFP has previously been successfully expressed in P. pastoris using the pPIC3 (Lenassi Zupan et al, 2004) and pPICZB vectors (Hisiger and Jolicoeur, 2005), both of which utilize the AOX1 promoter to drive intracellular gene expression (Sears et al, 1998;Gellissen, 2000). Once expressed, GFP does not usually interfere with cell growth apart from under rare circumstances (Keenan et al, 2007). In this work, GFPH6 gene expression using the pPICKanMX6B vector appears to be the equivalent of pPICZB under the conditions employed in this study.…”

Macrobrachium amazonicum: an alternative for microbiological monitoring of aquatic environments in Brazil

“…Crustaceans accumulate pollutants in their tissues, such as hydrocarbons, pesticides and heavy metals (YILMAZ & YILMAZ, 2007), which might increase the azole resistance rate among yeasts from the microbiota, due to the overexpression of effl ux pumps (KEENAN et al, 2007;MÜLLER et al, 2007), as a consequence of the chronic exposure to these chemical compounds. In this context, the use of this prawn as a sentinel for the isolation of Candida spp.…”