Abstract
Wild-type Aspergillus nidulans has an active transport system specific for urea which concentrates urea at least 50-fold relative to the extracellular concentration. It is substrate concentration dependent, with an apparent K m of 3×10−5 m for urea. Competition studies and the properties of mutants indicate that thiourea is taken up by the same system as urea. Thiourea is toxic at 5mm to wild-type cells of Aspergillus nidulans. Mutants, designated ureA1 to ureA16, resistant to thiourea have been isolated, and transport assays and growth tests show that they are specifically impaired in urea transport. The mutant ureA1 has a higher K m value than the wild type for thiourea uptake. The ureA locus has been assigned to linkage group VIII. ureA1 is recessive for thiourea resistance while semidominant for the low uptake characteristic. The urea uptake system is under nitrogen regulation, with l-glutamine as the probable effector. The mutants, meaA8 and gdhA1, which are insensitive to ammonium control of many nitrogen-regulated metabolic systems, are also insensitive to ammonium control of urea uptake, but both are sensitive to l-glutamine regulation.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Adelberg, E. A., Mandel, M., and Chen, G. C. C. (1965). Optimum conditions for mutagenesis by N-methyl-N'-nitro-N-nitrosoguanidine in Escherichia coli. Biochim. Biophys. Acta 18788.
Arst, H. N., and Cove, D. J. (1969). Methylammonium resistance in Aspergillus nidulans. J. Bacteriol. 981284.
Arst, H. N., and Page, M. M. (1973). Mutants of Aspergillus nidulans altered in the transport of methylammonium and ammonium. Mol. Gen. Genet. 121239.
Cohen, B. L. (1972). Ammonium repression of extracellular protease in Aspergillus nidulans. J. Gen. Microbiol. 71293.
Cooper, T. G., and Sumrada, R. (1975). Urea transport in Saccharomyces cerevisiae. J. Bacteriol. 121(2):571.
Cove, D. J. (1966). The induction and repression of nitrate reductase in the fungus Aspergillus nidulans. Biochim. Biophys. Acta 11351.
Cybis, J., and Weglenski, P. (1972). Arginase induction in Aspergillus nidulans. Eur. J. Biochem. 30262.
Dunn-Coleman, N. S., and Garett, R. H. (1980). The role of glutamine synthetase and glutamine metabolism in nitrogen metabolite repression, a regulatory phenomenon in the lower eucaryote Neurospora. Mol. Gen. Genet. 17925.
Kinghorn, J. R., and Pateman, J. A. (1975a). The structural gene for NADP L-glutamate dehydrogenase in Aspergillus nidulans. J. Gen. Microbiol. 86294.
Kinghorn, J. R., and Pateman, J. A. (1975b). Studies of partially repressed mutants at the tamA and areA loci in Aspergillus nidulans. Mol. Gen. Genet. 140137.
Kinghorn, J. R., and Pateman, J. A. (1975c). Mutations which affect amino-acid transport in Aspergillus nidulans. J. Gen. Microbiol. 86174.
Lineweaver, H., and Burk, D. (1934). The determination of enzyme dissociation constants. J. Am. Chem. Soc. 56658.
Mackay, E. M., and Pateman, J. A. (1982). The regulation of urease activity in Aspergillus nidulans. Biochem. Genet. 20763–776.
McCully, K. S., and Forbes, E. (1965). Use of p-fluorophenylalanine with master strains of Aspergillus nidulans. Genet. Res. 6352.
Neville, E. D. and Feller, D. D. (1965). An improved CO2 collection well for use in incubation studies. Analytical Biochemistry 11144–148.
Olszanska, B. (1968). Studies on the mechanism of urea uptake by plant roots. Acta Soc. Botan. Polon. 37(1):39.
Pateman, J. A., Kinghorn, J. R., Dunn, E., and Forbes, E. (1973). Ammonium regulation in Aspergillus nidulans. J. Bacteriol. 114943.
Pateman, J. A., Dunn, E., Kinghorn, J. R., and Forbes, E. (1974a). Ammonium and methylammonium transport in wild-type and mutant cells of Aspergillus nidulans. Mol. Gen. Genet. 133225.
Pateman, J. A., Kinghorn, J. R., and Dunn, E. (1974b). Regulatory aspects of L-glutamate transport in Aspergillus nidulans. J. Bacteriol. 119(2):534.
Pontecorvo, G., Roper, J. A., Hemmons, L. M., MacDonald, K. D., and Bufton, A. W. J. (1953). The genetics of Aspergillus nidulans. Adv. Genet. 5141.
Scazzocchio, C., and Darlington, A. J. (1968). The induction and repression of the enzymes of purine breakdown in Aspergillus nidulans. Biochim. Biophys. Acta 166557.
Segel, I. H., and Johnston, M. J. (1963). Synthesis and characterization of sodium cysteine-s-sulphate monohydrate. Anal. Biochem. 5330.
Sinha, U. (1969). Genetic control of the uptake of amino acids in Aspergillus nidulans. Genetics 62495.
Author information
Authors and Affiliations
Additional information
Formerly at the Department of Genetics, University of Glasgow, Glasgow, Scotland.
Rights and permissions
About this article
Cite this article
Pateman, J.A., Dunn, E. & Mackay, E.M. Urea and thiourea transport in Aspergillus nidulans . Biochem Genet 20, 777–790 (1982). https://doi.org/10.1007/BF00483973
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00483973