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. 2017 Aug 31;7:10224. doi: 10.1038/s41598-017-10758-4

Figure 1.

Figure 1

Development of an E. coli strain dependent on the L-asparaginase reaction. (A) Dependence on the ammonium produced by the L-asparaginase reaction: shown are colony formation of the strains BW after 48 h and BW2Δ after 72 h in complete minimal medium M9 agar that lacks ammonium chloride and was supplemented with increasing concentrations of Asn (0, 0.2, 0.5 and 2 mM) as the sole source of nitrogen. Whereas the BW strain can obtain the required nitrogen from hydrolyzing Asn, forming many colonies after only 48 h, the BW2Δ strain forms fewer and smaller colonies even after 72 h. (B) Dependence on the Asp produced by the L-asparaginase reaction: shown are colony formation of the strains BW after 48 h and BW5Δ after 72 h in complete minimal medium M9 agar supplemented with increasing concentrations of Asp (0, 0.2, 0.5 and 2 mM). Whereas growth in agar of the BW strain is not dependent on Asp, growth of the BW5Δ exhibits a dose response to this amino acid.