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. 2012 Jun 8;11:74. doi: 10.1186/1475-2859-11-74

Table 1.

Effect of pH up-shift on the secretion stress response inB. subtilis

Strain Genotype Plasmid Na2CO3a LacZ activityb
R-1645
168 ΔamyE::PhtrB-lacZ
pHY300PLK
-
6.7 ± 0.3
R-1645
168 ΔamyE::PhtrB-lacZ
pHY300PLK
+
6.5 ± 0.5
R-1646
MGB874 ΔamyE::PhtrB-lacZ
pHY300PLK
-
9.5 ± 0.1
R-1646
MGB874 ΔamyE::PhtrB-lacZ
pHY300PLK
+
9.1 ± 0.3
R-1645
168 ΔamyE::PhtrB-lacZ
pHYK38
-
700 ± 86
R-1645
168 ΔamyE::PhtrB-lacZ
pHYK38
+
200 ± 48
R-1646
MGB874 ΔamyE::PhtrB-lacZ
pHYK38
-
1700 ± 36
R-1646 MGB874 ΔamyE::PhtrB-lacZ pHYK38 + 590 ± 85

aB. subtilis derivative strains were grown in 2xL-Mal medium at 30°C. At the transition phase (12 h), a Na2CO3 solution was added to the growth medium at a final concentration of 0.9% (w/v). -, No addition; +, Addition.

bLacZ activity was determined after 48 h of cultivation. β-galactosidase-specific activities are reported in units (U) calculated using the following formula: 1000 x A420/reaction time (min) x OD600 of culture.