Table 1.

Results of V. cholerae attachment assays for O1 El Tor and classical biotype and O139 strains and corresponding isogenic mshA mutantsa

AssayBiotypeMediumGenotype (exoskeleton type)nStandardized attached cells mm−2 ± 1 SDWild-type:mutantANOVA results
FactorFP
1O1, El TorLBmshA+(clean)32,750.7 ± 658.333.2mshA273.1<0.0001
mshA(clean)382.9 ± 15.3Mucilage7.90.026
mshA+(mucilage)37,462.3 ± 1,434.659.5
mshA(mucilage)3125.4 ± 73.5Interaction2.30.172
2O139LBmshA+3527.9 ± 159.2NAbmshANANA
mshA30
3O1, classicalLBmshA+2874.1 ± 336.51.8mshA3.40.164
mshA3494.7 ± 142.8
4O1, classicalLBmshA+3353.4 ± 5.60.7mshA130.40.0003
mshA3534.9 ± 27.0
5O1, El TorM9mshA+320,386.5 ± 9,363.35.1mshA24.40.0078
mshA33,996.0 ± 743.1
6O1, El TorLBmshA+3651.2 ± 107.4c8.9mshA23.80.0081
mshA372.9 ± 50.0c
  • a The attachment substrate was exoskeletons of D. pulex, and in assay 1, attachment was also compared for “clean” exoskeletons and exoskeletons coated with mucilage from algal secretions (see text for explanation).n, number of exoskeletons examined. The medium used was LB in all assays except assay 5, which used M9, a nutrient-limited medium. ANOVA was used to compare standardized attached cells (see text). Cells were allowed to attach during a 2-h incubation period in medium with aV. cholerae concentration of ∼106 cells ml−1. Wild-type:mutant, ratio of attached cells for the two genotypes. ANOVA results shown are factor tested,F-statistic, and P value for factor tested.

  • b NA, not applicable; statistics cannot be applied.

  • c Different location on exoskeleton examined than in other assays.