ISSN:
1432-072X
Keywords:
Key words Nitrate assimilation
;
Nitrate reductase
;
Paracoccus denitrificans
;
Thiosphaera pantotropha
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A Paracoccus denitrificans strain (M6Ω) unable to use nitrate as a terminal electron acceptor was constructed by insertional inactivation of the periplasmic and membrane-bound nitrate reductases. The mutant strain was able to grow aerobically with nitrate as the sole nitrogen source. It also grew anaerobically with nitrate as sole nitrogen source when nitrous oxide was provided as a respiratory electron acceptor. These growth characteristics are attributed to the presence of a third, assimilatory nitrate reductase. Nitrate reductase activity was detectable in intact cells and soluble fractions using nonphysiological electron donors. The enzyme activity was not detectable when ammonium was included in the growth medium. The results provide an unequivocal demonstration that P. denitrificans can express an assimilatory nitrate reductase in addition to the well-characterised periplasmic and membrane-bound nitrate reductases.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002030050417
Permalink
