Table 4.

Metabolism of micromolar levels of [14C]GB and [14C]DMSA by unstressed cultures of S. meliloti 102F34a

14C-labeled onium suppliedAmt of radioactivity supplied (103dpm)Amt of 14C recovered in medium (103dpm)Amt of 14C recovered in cellular fractions (103 dpm)Total dpm recovered (103)
CO2 fractionEIFESF
[1,2-14C]GB (13.9 μM)22437 (16)b , c 67 (30)99 (44)5 (2)208
[methyl-14C]GB (1.8 μM)22237 (17)c 104 (47)58 (26)4 (2)203
[1-14C]DMSA (1.8 μM)228210 (92)d 1 (<1)1 (<1)10 (4)222
[methyl-14C]DMSA (1.8 μM)244163 (67)e 37 (15)30 (12)6 (3)236
  • a S. meliloti 102F34 was inoculated into LAS medium containing a 14C-labeled onium compound (3.7 kBq/ml). Cells were harvested after 14 h of incubation and extracted in ethanol as described in the text.

  • b The numbers in parentheses are percentages of the radioactivity supplied.

  • c More than 95% of the radioactivity recovered in the medium comigrated with [14C]GB during high-voltage electrophoresis and paper chromatography.

  • d A total of 80% of the radiocarbon in the medium was recovered in [1-14C]MTA and in [1-14C]TGA, as determined by autoradiography with the Packard InstantImager following thin layer chromatography with CH2Cl2-ethanol (1:1, vol/vol).

  • e A total of 70% of the label in the medium was recovered in [methyl-14C]MTA.