Testing the limits of biological tolerance to arsenic in a fungus isolated from the River Tinto.
The Tinto river in Spain, with its high acidity and heavy metal concentrations (As, Cu, Cr, Zn), is an example of an environment hostile to life. Yet despite these extreme conditions, the site possesses a great diversity of eukaryotic life forms. We report the isolation of a filamentous fungus able to grow at 200 mM arsenic ( approximately 15 000 p.p.m.), i.e. a concentration 20-fold above that withstood by the reference microorganisms Escherichia coli, Saccharomyces cerevisiae and Aspergillus nidulans, and 200 times greater than that tolerated by Aspergillus niger. Based on morphological, physiological and genotypic criteria, the strain belongs to the genus Aspergillus. High concentrations of the metalloid induced vacuolation, suggesting that this organelle is someway connected to arsenic tolerance. Concentrations that are lethal to other organisms do not stress Aspergillus sp. P37. The fungus was capable of removing arsenic from culture media. In addition to arsenic hyper-resistance, it also displayed a polyresistant phenotype to copper and chromium.
Cánovas
David
D
Centro Nacional de Biotecnología, UAM-CSIC, Cantoblanco, Madrid 28049, Spain.
Durán
Consuelo
C
Rodríguez
Nuria
N
Amils
Ricardo
R
de Lorenzo
Víctor
V
D001151:Arsenic / Q000378:metabolism / Q000494:pharmacology*; D001230:Aspergillus / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D002857:Chromium / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology; D025141:Drug Resistance, Fungal; D005618:Fresh Water / Q000382:microbiology*; D019216:Metals, Heavy / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D013030:Spain; D014617:Vacuoles / Q000502:physiology
D019216:Metals, Heavy; D002857:Chromium; D003300:Copper; D001151:Arsenic