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Table 3 Phenotypic characteristics of deletion mutants and WT strain tested for motility, RpoS activity, calcofluor binding and changes in extracellular matrix.

From: The transcriptional programme of Salmonella enterica serovar Typhimurium reveals a key role for tryptophan metabolism in biofilms

Strain Genotype Biofilm Capacitya Motility RpoS activityb Calcofluor bindingc   EPS production
      25°C 37°C 25°Cd Morphology 37°Cd Morphology
SL1344 wild-type + + + L L DR R DR R
JH3185 ΔtrpE --- + + L L DR S R R/S
JH3187 ΔSTM0341 --- + + L L DR R DR R
JH3180 ΔssrA --- + + L H DR R DR R
JH3181 ΔssrA/pssrAB + + + L H DR S DR S
JH3179 ΔORF319 + + + L H DR R DR R
JH3182 ΔSTM2779 + + + H L DR S DR R
JH3183 ΔygaT + + + H L DR R DR R
JH3184 ΔybaY + + + H L DR R DR R
JH3186 ΔyhfG + + + H L DR R DR R
JH3188 Δmtr + + + H L DR R DR R
JH3189 ΔpspABCDEF + + + H L DR R DR R
JH3142 ΔrpoS --- + --- --- --- W R W S
  1. a. Biofilm formation is based on attachment under static conditions after 24 and 48 h of growth in CFA medium at 25°C. Symbols: (+) = WT biofilm growth; (-) = severely reduced attachment.
  2. b. RpoS activity as defined by catalase activity in the semi-quantitative assay as described by Zambrano et al., [106].
  3. c. Calcofluor binding was assessed following growth of SL1344 and mutant strains at 25 and 37°C on CFA agar supplemented with fluorescent brightener 28. Fluorescence levels are reported as low (L) or high (H) as compared to a cellulose-deficient rpoS mutant (-).
  4. d. Colony colour was reported as dark red (DR), red (R), or white (W) with dark red indicating WT EPS production. Colony morphology was assessed as rough (R) or smooth (S) following overnight growth on CFA agar supplemented with CR dye at 25 and 37°C. Colony morphology of WT SL1344 and mutant strains were compared to strain positive (S. Typhimurium LT2) and negative (ΔrpoS) for the rdar morphotype.