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Page 12 of 19 Ambros et al. Microbiome Res Rep 2023;2:34 https://dx.doi.org/10.20517/mrr.2023.18

Figure 3. Growth curves of lysogenic L. curvatus strains after induction via UV light (A) or mitomycin C (B) treatment and without such
treatment. Optical density was measured at 600 nm (OD ) (Y-axis; scale: 0-3.5) over the time (X-axis; scale 0-13) in hours (h).
600
For the induction in (A), 4-min UV light exposure was used (no UV light exposure for control); For the induction in (B), different
mitomycin C concentrations (20 µg/mL, 10 µg/mL, 5 µg/mL, 0.5 µg/mL, 0.2 µg/mL, and 0 µg/mL as control) were used. In (A),
induction was performed directly before the measurement was started; In (B), the addition of mitomycin C to the bacterial cultures is
indicated by an arrow. L. curvatus: Latilactobacillus curvatus.

Figure 4. TEM derived micrographs of purified post-induction lysates of different L. curvatus strains. For negative staining of the
samples, 2% uranyl acetate was used. (A) L. curvatus TMW 1.591; (B) L. curvatus TMW 1.706; (C) L. curvatus TMW 1.1365; (D)
L. curvatus TMW 1.2272. Scale bar: 50 nm. The microscope was operated at 80 kV in zero-loss mode. TEM: Transmission electron
microscopy. L. curvatus: Latilactobacillus curvatus.

Comparing this data to the results of our study, we found that L. curvatus can also reach high numbers (up
to 14) in prophage count (discounting completeness) and has a mean of 4.6 prophages per strain (206
prophage sequences in total over 45 genomes analysed). This would therefore be an even higher value than
what can be found for L. paracasei but with a lower count of “maximum intact prophages” (three for
L. curvatus in contrast to five for L. paracasei) at a similar intact prophage occurrence (73.3% of analysed
L. curvatus strains harbouring intact prophages in contrast to 72.1% in L. paracasei) . Notably, the six
[14]
strains included for the prophage induction experiments were also included in the predictive analyses,
which may have increased the overall number of intact predicted prophages to some extent.