Table 2.

Measurement of GFP-TonB anisotropy in exbBD± bacteria

BN1071/pGTBN1071ΔexbBD /pGT
StudyRAvgSDnRAvgSDnt test resultNull hypothesis probability
10.5470.100120.2980.179244.92<0.0001
20.4930.142360.3110.080245.72<0.0001
30.4140.166260.3060.053313.420.0012
40.3770.160290.1730.096376.55<0.0001
50.4590.198500.2810.153494.99<0.0001
  • On five occasions, E. coli strains BN1071/pGT and BN1071 ΔexbBD/pGT were grown in MOPS minimal media, suspended in PBS, and subjected to fluorescence microscopy. We measured anisotropy (R) in individual cells adhered to the coverslip. After n measurements, we calculated mean anisotropy (RAvg) and SD of the mean, and performed Student t tests to determine the statistical significance of the different mean values. In each case, the null hypothesis probability was <0.01, indicating that GFP-TonB was more mobile in ΔexbBD bacteria.