Nickel Requirement of a Urease-deficient Mutant in Aspergillus nidulans

Department of Genetics, University of Glasgow, Church Street, Glasgow G11 5JS ABSTRACT Summary: The addition of nickel ions restored urease activity in vivo and ability to grow on urea in a mutant strain of Aspergillus nidulans otherwise unable to utilize urea. This strain carries a mutation in the ureD locus, one of four loci involved in urea utilization. No other urease-deficient strains tested responded to the presence of nickel ions. The analogous characteristics of the ureD mutant and the nitrate reductase and xanthine dehydrogenase associated cnxE mutants in Aspergillus nidulans are discussed. It is postulated that the ureD locus is in some way involved in the production or incorporation of a nickel cofactor essential for urease activity. * Present address: Department of Genetics, Research School of Biological Sciences, Australian National University, P.O. Box 475, Canberra, A.C.T. 2601, Australia.