Figure 1.
Influence of maternal immunization on C3 and Bf levels in the WBHs and egg extracts.
Three immunized female D. rerio and three control females as well as their released eggs were sampled every 7 days after the primary immunization. Whole body homogenates (WBHs) and egg extracts were prepared, and used for the measurement of complement component levels. The complement component contents are presented as percentages of total protein of the WBHs and egg extracts. The symbol * represents a significant difference (p<0.05).
Figure 2.
Influence of maternal immunization on the ACH50 in the WBHs and egg extracts.
Three immunized female D. rerio and three control females as well as their released eggs were sampled every 7 days after the primary immunization. WBHs and egg extracts were prepared, and used for the measurement of hemolytic activities. The symbol * represents a significant difference (p<0.05) between the time-points indicated and day 0 post the primary immunization.
Figure 3.
Effects of anti-C3 and anti-Bf antibodies on the hemolytic activity.
The fish were injected first with the formalin-killed A. hydrophila, and , 6 days later with anti-C3 antibodies and anti-Bf antibodies, respectively.. The WBHs were prepared at 24 h after the injection of anti-C3 antibody or anti-Bf antibody, and the ACH50 was examined. Ah: A. hydrophila.
Figure 4.
Influence of maternal immunization on the anti-infection activity of D. rerio embryos.
The embryos from the immunized and control females were both challenged by injection of live A. hydrophila 24–28 h post fertilization, and the cumulative mortalities at 24 h after injection were counted. The symbol * represents a significant difference (p<0.05) between the time-points indicated and day 0 post the primary immunization.
Figure 5.
PCR analysis of A. hydrophila 16S rRNA gene in the embryos.
(A) A total of 10 embryos were collected each time at 0, 12 and 24 h post the bacterial injection, respectively, and DNAs were isolated and used to amplify the specific region of A. hydrophila 16S rRNA gene. (B) A single embryo was collected each time at 0, 12 and 24 h post the bacterial injection, respectively, and DNAs were isolated and used to amplify the specific region of A. hydrophila 16S rRNA gene. The PCR products were electrophoresed in 1% agarose and the bands were recorded using the gel imaging system. M: Marker; C: Control.
Figure 6.
Influence of anti-C3 and anti-Bf antibodies on the anti-infection activity of D. rerio embryos.
The embryos were first microinjected at 24–28 h post fertilization with antibodies against C3 or Bf, and then challenged by injection of live A. hydrophila 1 h later. The cumulative mortalities were counted at 24 h following the bacterial injection. The symbol * means a significant difference (p<0.05).
Figure 7.
A schematic diagram of the experiment.