Figure 5.

Characterization of the endolysin PlyBt33.(a) Lysis of viable cells from five different Bacillus species and one E. coli strain by PlyBt33. Tests were carried out with a final protein concentration of 2 μM at 37°C in 20 mM Tris-HCl (pH 8.0). The initial OD600 of each strain suspension was 0.8. Crude extract of E. coli M15 containing pQE-30 was used as a control to treat B. thuringiensis strain HD-73. (b) pH-dependent activity of PlyBt33. Tests were carried out with a final protein concentration of 2 μM at 37°C in 20 mM Tris at varying pH levels. (c) Temperature-dependent activity of PlyBt33. Tests were carried out with a final protein concentration of 2 μM in 20 mM Tris-HCl (pH 8.0) at varying temperatures. (d) Temperature stability of PlyBt33. Proteins were first treated at different temperatures for 1 h and then the tests were carried out with a final protein concentration of 2 μM at 37°C in 20 mM Tris-HCl (pH 8.0). In (b), (c), and (d), decrease of OD600 (%) = (1− the absorbance of the bacterial suspension at the end of each treatment / the absorbance at the beginning of each treatment) × 100%.

Yuan et al. BMC Microbiology 2012 12:297   doi:10.1186/1471-2180-12-297
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