Extended Data Fig. 6: Plasmid interference induced by SPARDA.

a, Measurements of CFU numbers for E. coli strains containing empty pBAD (Amp^R) or pBAD encoding NbaSPARDA (WT or CD and MID mutants), and transformed with pACYC (Cm^R, left) or pCDF (Sm^R, right) interfering plasmids. The cells were grown for 2.5 hours at 30 °C (see Fig. 3b and panel d in this figure) in the presence of Amp and 0.1% Ara (to induce expression of SPARDA), serial dilutions were plated on LB agar containing Amp or Cm or Sm and 0.5% Glc (to repress SPARDA expression), and CFU numbers were counted after overnight growth. The calculations of the CFU numbers for the pCDF and pACYC experiments are shown in Fig. 3d and in panel e in this figure, respectively. b, Measurements of CFU numbers for E. coli strains containing empty pBAD (Amp^R) or pBAD encoding CmeSPARDA in the absence and in the presence of pCDF (Sm^R). The cells were grown for 6 hours at 30 °C (see Fig. 3c) in the presence of Amp and 0.1% Ara (to induce expression of SPARDA), serial dilutions were plated on LB agar containing Amp (left) or Sm (right) and 0.5% Glc (to repress expression of SPARDA), and CFU were counted as described above. c, Numbers of viable cells in cell cultures expressing wild-type CmeSPARDA (WT) or containing empty pBAD, depending on the presence of the pCDF plasmid, measured in the presence of Amp or Sm (calculation of data from panel b). Means and standard deviations from three independent experiments. Statistically significant differences are indicated (from left to right: **p = 0.002, **p = 0.005, ****p = 0.00005). d, Growth of E. coli strains expressing WT or mutant NbaSPARDA from pBAD, or containing control empty pBAD, depending on the presence of the second interfering plasmid pACYC184. Means and standard deviations from 6 independent experiments. The growth curves obtained in the absence of pACYC184 (left panel) correspond to the left panel in Fig. 3b. e, Numbers of viable cells (CFU) in cell cultures (shown in panel d) expressing NbaSPARDA or its mutants, depending on the presence of the pACYC184 plasmid (Cm^R), measured in the presence of Amp or Cm. Means and standard deviations from 3 independent experiments. Statistically significant differences are indicated (from left to right: *p = 0.026, **p = 0.004, ****p = 0.00004). f, Growth of E. coli strains expressing CmeSPARDA or containing empty pBAD, in the absence and in the presence of pACYC184. Means and standard deviations from 6 independent replicate experiments. g, CFU numbers in cell cultures grown for 7 hours (shown in panel f), expressing CmeSPARDA and containing pACYC184, measured in the presence of Amp or Cm. Means and standard deviations from 3 independent experiments. Statistically significant differences are indicated (from left to right: **p = 0.008, **p = 0.002, ****p = 0.000006). h, Numbers of viable cells in cell cultures expressing NbaSPARDA or containing empty pBAD, in the absence and in the presence of RSF1010 or pMB9. The cells were grown for 2.5 hours at 30 °C hours in the presence of 0.1% Ara to induce SPARDA expression and CFU numbers were determined as described above. Means and standard deviations from 3 independent experiments. Statistically significant differences are indicated (from left to right: *p = 0.044, **p = 0.002, *p = 0.02). In all cases, statistics was calculated using the two-sided t-test for independent samples with Bonferroni correction.