TABLE 4.

LsdA secretion in G. diazotrophicus strainsa

StrainIntracellular LsdA activity (U mg−1)Extracellular LsdA activity (U ml−1)
SRT420 ± 432 ± 4
M3175 ± 65 ± 2
AD672 ± 54 ± 2
AD869 ± 55 ± 2
AD977 ± 65 ± 2
M31(pALS117)19 ± 328 ± 4
M31(pALS118)73 ± 55 ± 2
  • a Bacteria from a 1-ml culture, (optical density at 620 nm, 8 ± 0.2) were spun down at 6,500 × g for 15 min. Supernatants were assayed for extracellular LsdA activity. Cells were washed in Tris-EDTA buffer; resuspended in 0.5 ml of distilled water, and disrupted in the presence of 0.2% (wt/vol) sodium dodecyl sulfate and 4% (vol/vol) chloroform with incubation for 15 min at room temperature. Chloroform and cell debris were removed by centrifugation at 6,500 × g for 5 min, and cell extracts were assayed for intracellular LsdA activity. The values are means ± standard deviations (n = 6).