FIG 1.
Rubber oxygenase activities of RoxAXsp- and RoxBXsp-harboring Xanthomonas sp. (A) Cells of ΔroxA Xanthomonas sp. strain 35Y harboring a roxAXsp gene or a roxBXsp gene under the control of a rhamnose-dependent promoter were spotted onto a polyisoprene latex overlay (LOV) agar plate supplemented with 0.1% rhamnose and were incubated at room temperature for 10 days (top row). Note the formation of weak clearing zones around the colonies of RoxAXsp- and RoxBXsp-expressing clones on LOV plates and its absence in the control strain (ΔroxA Xanthomonas sp. strain 35Y). The bottom row shows the same colonies after staining with fuchsin solution. Note the formation of large pink halos around the RoxBXsp-expressing colony, which indicates the formation of degradation products with aldehyde groups. The almost complete absence of pink halos around the RoxAXsp colony can be explained by the efficient uptake and consumption of RoxAXsp-produced ODTD. (B) Polyisoprene latex (0.1% final concentration) was added to cell-free culture fluid of roxAXsp- or roxBXsp-expressing clones that had been grown on NB medium in the presence (+) or absence (−) of 0.1% rhamnose for 3 days at room temperature. After incubation for 2 h at room temperature, 100 μl fuchsin solution was added to stain aldehyde-containing compounds.