TABLE 1.

Hydrogen metabolism in Bradyrhizobium Hup+ strains

Strain/hostBacteroid hydrogenase activityaNodule H2 evolutionb
Bradyrhizobium sp. (Lupinus)/L. albus
    UPM860510 ± 304.1 ± 0.6
    62450 ± 105.3 ± 0.8
    466820 ± 600.5 ± 0.2
    Z892,070 ± 1600.3 ± 0.1
    IM43B880 ± 100.6 ± 0.4
Bradyrhizobium sp. (Vigna)/V. unguiculata
    M2350 ± 200.4 ± 0.1
    M51,500 ± 240<0.1
    M181,120 ± 170<0.1
    M211,080 ± 210<0.1
    M43840 ± 10<0.1
    B781,480 ± 50<0.1
    B96520 ± 300.2 ± 0.1
    B9720 ± 103.6 ± 0.1
    UPM938510 ± 110<0.1
  • a Hydrogenase activities were determined in bacteroid suspensions and are expressed in nmol H2 h−1 (mg prot)−1. Protein content of bacteroid suspensions was determined by the bicinchoninic acid method (20). Values are the averages of three independent determinations ± standard errors.

  • b Values (μmol H2 h−1 g−1 fresh weight of nodules) are the averages of three independent determinations with two replicates ± standard errors. Values of <0.1 indicate rates of hydrogen evolution not detectable with the amperometric method.