title: Biochemical characterization of N-methyl N'-nitro-N-nitrosoguanidine-induced cadmium resistant mutants of Aspergillus niger.
abstract: Two cadmium resistant mutants (Cd1 and Cd2) of Aspergillus niger, among the six isolated by mutagenization with N-methyl N'-nitro-N-nitrosoguanidine (MNNG) at pH 6.4 were selected for the study. Analysis of lipid composition of the mutants and the wildtype indicated that total lipid as well as individual lipids of the cadmium resistant mutants were changed as compared with that of the wildtype. The increased activities of metal-lothionein and reduced activities of D-xylose isomerase and L-phenylalanine ammonia lyase in cell free extract of the cadmium resistant mutants suggested that mutants could allow high concentration of cadmium salt as compared with that of the wildtype. The respiratory activity and intracellular as well as extracellular Cd2+ concentration of the mutants reflected the high tolerance of the Cd mutants to cadmium ion.
authors.affiliation: Department of Biochemistry and Biophysics, University of Kalyani, Nadia 741 235, India.
authors.forename: Samar Kumar
authors.initials: SK
authors.lastname: Pal
authors.forename: Tapan Kumar
authors.initials: TK
authors.lastname: Das
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000032:analysis; D001234:Aspergillus niger / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D002104:Cadmium / Q000032:analysis / Q000633:toxicity*; D004252:DNA Mutational Analysis; D025141:Drug Resistance, Fungal / Q000235:genetics*; D008055:Lipids / Q000737:chemistry; D008668:Metallothionein / Q000032:analysis; D008769:Methylnitronitrosoguanidine / Q000633:toxicity*; D016296:Mutagenesis / Q000235:genetics; D025282:Mycelium / Q000737:chemistry; D010101:Oxygen Consumption / Q000235:genetics / Q000502:physiology; D010650:Phenylalanine Ammonia-Lyase / Q000032:analysis; D016019:Survival Analysis
chemical_list: D008055:Lipids; D002104:Cadmium; D008769:Methylnitronitrosoguanidine; D008668:Metallothionein; D010650:Phenylalanine Ammonia-Lyase; D019747:Aldose-Ketose Isomerases; C023298:xylose isomerase