Effects of surface characteristics on the transport of multiple Escherichia coli isolates in large scale columns of quartz sand - Transport of Multiple Escherichia Coli Transport in Saturated Porous Media - page 19

2.3.3 Correlation between averaged sticking efficiencies and E. coli cell properties

In both DI and AGW there was no significant correlation between the strain averaged sticking
efficiency, , and cell sphericity, outer surface potential or hydrophobicity ( Tables 2.2 and

Α

strain

2.3 ) .

Table 2.2: Correlation matrix between the strain averaged sticking efficiency ( strai Α ) and

cell surface properties for the experiments in DI. P values are in brackets and
statistically significant (

p ≤ 0.05

) correlations are in bold.

Motility Ag43 Hydrophobicity Zeta

Α

strain

potential

Motility

0.724
(0.052)

Ag43 0.815

(0.046)

0.706
(0.092)

Hydrophobicity 0.080

(0.440)

-0.261
(0.309)

0.064
(0.459)

Zeta potential -0.006

(0.496)

0.337
(0.257)

0.475
(0.209)

-0.634
(0.088)

Sphericity -0.110

(0.418)

-0.284
(0.293)

0.315
(0.303)

-0.25
(0.316)

0.663
(0.076)

Table 2. 3: Correlation matrix between the strain averaged sticking efficiency ( strai Α ) and

cell surface properties for the experiments in AGW. P values are in brackets.

Motility Ag43 Hydrophobicity Zeta

potential

Α

strain

Motility 0.423

(0.202)

Ag43 0.741

(0.076)

0.706
(0.092)

Hydrophobicity 0.531

(0.139)

-0.515
(0.148)

-0.169
(0.393)

Zeta potential 0.229

(0.332)

-0.218
(0.339)

0.033
(0.479)

0.294
(0.286)

Sphericity -0.080

(0.44)

-0.284
(0.293)

0.315
(0.303)

0.068
(0.449)

0.074
(0.444)

In order to avoid underestimating the low sticking efficiency values, when calculating the mean
of all strai Α values per experiment, we also computed the average of the log-transformed values.
However, the differences between the average sticking efficiency, strai Α , and the average of the
log-transformed sticking efficiency were negligible, and we therefore did not consider log-
transformed averaged sticking efficiencies. In DI, however, there was a high positive correlation
between Ag43 expression and the strain averaged sticking efficiency ( r = 0.815, p = 0.046) and