A new short-term toxicity assay using Aspergillus awamori with recombinant aequorin gene

摘要

BackgroundMost currently available short-term toxicity assays are based on bacterial cells. Therefore there is a need for novel eukaryotic microbial bioassays that will be relevant to higher eukaryotes such as animals and plants. Ca²⁺ is a universal intracellular signalling molecule found in all organisms from prokaryotes to highly specialized animal cells. In fungi calcium has been demonstrated to be involved in control of many important processes. The recombinant aequorin gene from the jellyfish Aequorea victoria responsible for the expression of the Ca²⁺-sensitive aequorin photoprotein has been cloned in the filamentous fungus Aspergillus awamori. This has allowed real life monitoring of [Ca²⁺]c changes in living fungal cells. When subjected to different physico-chemical stimuli fungal cells respond by transiently changing the concentration of free Ca²⁺ in the cytosol ([Ca²⁺]c) and the pattern of these changes (Ca²⁺ signature) is specific to each particular stimulus. Therefore it was interesting to investigate whether different environmental toxicants would be able to affect the pattern of [Ca²⁺]c changes in a reproducible and dose dependant manner.