Nickel transport in nickel-resistant strains ofNeurospora crassa
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- Maruthi Mohan, P., Pratap Rudra, M.P. & Sastry, K.S. Current Microbiology (1984) 10: 125. doi:10.1007/BF01576771
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Transport of Ni2+ has been studied in three Ni2+-resistant strains ofNeurospora crassa (NiR1, NiR3) and NiR3) and in the parent wild strainN. crassa Em 5297a. Several strainspecific differences have been found. Rates of Ni2+ uptake were NiR2>NiR1>Em>>NiR3. While Km for Ni2+ uptake was similar, Vmax values were sharply different, with NiR3 having the lowest value. Observed uptake was entirely due to transport into the intracellular phase. Transport was strongly pH dependent only in Em, NiR1, and NiR2, which had a pH optimum at 4; optimum was at pH 5 for NiR3. Mg2+ was powerfully inhibitory to Ni2+ uptake in NiR1 and NiR2, but was less efficient in NiR3; in contrast, Mn2+ was most inhibitory in NiR3. It has been suggested that Ni2+ resistance in NiR3 is specifically due to lowered levels of the Ni2+ transport system herein.