Nitrate respiratory metabolism in an obligately autotrophic hydrogen-oxidizing bacterium, Hydrogenobacter thermophilus TK-6

Suzuki, M Cui, ZJ Ishii, M Igarashi, Y

M. Suzuki et al., Nitrate respiratory metabolism in an obligately autotrophic hydrogen-oxidizing bacterium, Hydrogenobacter thermophilus TK-6, ARCH MICROB, 175(1), 2001, pp. 75-78

19

INGLESE

Article

Microbiology

ARCHIVES OF MICROBIOLOGY

0302-8933 → ACNP

175

1

2001

75 - 78

ISI

0302-8933(200101)175:1<75:NRMIAO>2.0.ZU;2-A

Hydrogenobacter thermophilus strain TK-6 was observed to grow anaerobically on nitrate as an electron acceptor when molecular hydrogen was used as an energy source. Nitrite was detected as the product of a respiratory reactio n. (NO)-N-15,(N2O)-N-15, and N-15(2) were detected with (NaNO3)-N-15 as an electron acceptor. Western immunoblot analysis showed that cell-free extrac ts from cells grown on nitrate reacted with antibodies against heme cd(1)-t ype nitrite reductase from Pseudomonas aeruginosa. The positive bands, whic h had molecular masses similar to that of the heme cd(1)-type nitrite reduc tase, were also stained by heme staining. These results indicate that nitri te reductase of strain TK-6 is a heme cd(1)-type enzyme. Activity of ATP:ci trate lyase, one of the key enzymes of the reductive TCA cycle, was detecte d in cell-free extract of cells cultivated on nitrate, which indicates that the cycle operates during anaerobic growth.