Figure 7.

Autolysis assay of CD. (a) CD strain 630 was cultured in GAM broth (closed circle) or the conditioned medium prepared with culture supernatants derived from BT (closed square) or ΔgcpE (closed triangle). The CD cells were suspended in PBS containing 0.02% Triton X-100. Cell lysis was monitored by a decrease in OD₅₉₀. The percent reduction in the initial OD₅₉₀ was calculated every 10 or 30 min until 2 h post-incubation. At each time point, significant differences with p-value less than (a) 0.01, and (c) 0.05 when compared with the control (CD cultured in GAM); (b) significant differences between BT and ΔgcpE with a p-value less than 0.01. (b) Lactate dehydrogenase (LDH) activity released into the 24-h culture supernatant of CD in GAM or the conditioned medium prepared with culture supernatant of BT or ΔgcpE. LDH activity was determined using CytoTox 96 Non-Radioactive Cytotoxicity Assay kit (Promega), and the signal from the test was recorded as absorbance at 490 nm. * Significant difference with p-value less than 0.01.