Open AccessNickel is essential for active hydrogenase in free‐living Frankia isolated from Casuarina
Author(s) -
Sellstedt Anita,
Smith Geoffrey D.
Publication year - 1990
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1990.tb13966.x
Subject(s) - frankia , hydrogenase , casuarina , nitrogenase , biology , actinorhizal plant , botany , microbiology and biotechnology , bacteria , symbiosis , nitrogen fixation , biochemistry , enzyme , root nodule , genetics
1. Summary Five free‐living Frankia strains isolated from Casuarina were investigated for occurrence of hydrogenase activity. Nitrogenase activity (acetylene reduction) and hydrogen evolution were also evaluated. Acetylene reduction was recorded in all Frankia strains. None of the Frankia strains had any hydrogenase activity when grown on nickel‐depleted medium and they released hydrogen in atmospheric air. After addition of nickel to the medium, the Frankia strains were shown to possess an active hydrogenase, which resulted in hydrogen uptake but no hydrogen evolution. The hydrogenase activity in Frankia strain KB5 increased from zero to 3.86 μ mol H 2 (mg protein) −1 h −1 after addition of up to 1.0 μ M Ni. It is likely that the hydrogenase activity could be enhanced even more as a response on further addition of Ni. It is indicated in this study that absence of hydrogenase activity in free‐living Frankia isolated from Casuarina spp. is due to nickel deficiency. Frankia living in symbiosis with Casuarina spp. show hydrogenase activity. Therefore, the results also indicate that the hydrogenase to some extent is regulated by the host plant and/or that the host plant supplies the symbiotic microorganism with nickel. Moreover, the result shows that this Frankia is somewhat different from Frankia isolated from Alnus incana and Comptonia peregrina ., i.e., Frankia isolated from A. incana and C. peregrina showed a small hydrogen uptake activity even without addition of nickel.