Fig. 3 Expression level of PCP vaccine antigen in four
bicistronic T7 expression vectors.
Line M: Protein marker, Line 1: BL21 WT strain, Line 2: pET28 without
target gene, Line 3-7 represented the target protein expression of
vector pET28a, pET28-HT5, pET28-HT8, pET28-HP11Y, and pET28-HP12Y,
respectively. (A), (B), and (C) represented the SDS-PAGE analysis of
Oml1, Oml7, and ApxⅡ, respectively.
Approximately 5 μL culture supernatant was loaded onto each lane. (D),
(E), and (F) represented the relative protein yield of Oml1, Oml7 and
ApxⅡ in BCD vectors per liter of cells, respectively.
Fig. 4 Effects of cultivation temperature and induction
conditions on the production of PCP vaccine proteins.
For the optimization experiment of cultivation temperature, the
OD600 and protein yield at 37 ℃ were used as the
control, defined as 1. For the optimization experiment of induction
conditions, the OD600 and protein yield with 1.0 mM IPTG
addition and 0 h pre-induction period was used as the control, defined
as 1. (A) Effect of cultivation temperature on Oml1 production. (B)
Effect of cultivation temperature on Oml7 production. (C) Effect of
cultivation temperature on ApxⅡ production. (D) Effect of IPTG
concentration on Oml1 production. (E) Effect of IPTG concentration on
Oml7 production. (F) Effect of IPTG concentration on ApxⅡ production.
(G) Effect of pre-induction period on Oml1 production. (H) Effect of
pre-induction period on Oml7 production. (I) Effect of pre-induction
period on ApxⅡ production.