Fig. 1

PBD-1 PCR amplification and recombinant plasmid digestion A. The results of reverse transcription cDNA PCR amplification: M1. DNA 2 000 Marker; 1. Porcine spleen's cDNA. B. Positive plasmid double enzyme digestion electrophoresis results: M2. DNA 10 000 Marker; 2. Suspected positive plasmid of pET28a-SUMO-PBD-1"

Fig. 2

Purification condition screening, purification and digestion of recombination PBD-1 protein A. The selection of the optimal elution concentration; B. The purification of recombinant PBD-1; C. The digestion of recombinant PBD-1; M1. Protein marker; M2. Ultra-low molecular weight protein marker; 1. Supernatant after sonication; 2. Flow-through; 3-4, 11-12. Washing; 5-10. 25-250 mmol·L－1 imidazole elution; 13-19. 100 mmol·L－1 imidazole elution; 20. PBD-1-SUMO; 21. Digested for 18 h; 22. Digested for 22 h"

Fig. 3

Microbial inhibition test of recombinant PBD-1 to E. coli 13-1(A)、S. aureus 4-1(B) and S. epidermidis 25-1(C) Lines with different shaped dots show the growth of bacteria with different concentration of PBD-1; Negative control represents negative control"

Fig. 4

Sterilization Kinetic curve of recombinant PBD-1 to E. coli 13-1(A)、S. aureus 4-1(B) and S. epidermidis 25-1(C)"

Fig. 5

Appearance of mammary glands of mice mastitis model A-C. Low-, medium-and high-dose groups of S. aureus 4-1; D-F. Low-, medium-and high-dose groups of E. coli 13-1; G. Normal saline group; H. Blank control group"

Fig. 6

Histopathological appearance of mouse mammary gland(400×) A-C. Low-, medium-and high-dose groups of S. aureus 4-1; D-F. Low-, medium-and high-dose groups of E. coli 13-1; G. Normal saline group; H. Blank control group"

Table 1

Bacteria counts of mammary glands of mice mastitis model infected with E. coli 13-1 and S. aureus 4-1"

Fig. 7

Appearance of mammary glands of mice mastitis treated by recombinant PBD-1 A-D. Intramammary perfusion with normal saline, enrofloxacin, PBD-1 82 μg·mL－1 and PBD-1 164 μg·mL－1 after infected with S. aureus 4-1, respectively. E-H. Intramammary perfusion with normal saline, enrofloxacin, PBD-1 82 μg·mL－1 and PBD-1 164 μg·mL－1 after infected with E.coli 13-1, respectively. Ⅰ. Blank control"

Fig. 8

Histopathological appearance of mouse mammary gland (400×) A-D. Intramammary perfusion with normal saline, enrofloxacin, PBD-1 82 μg·mL－1 and PBD-1 164 μg·mL－1 after infected with S. aureus 4-1, respectively. E-H. Intramammary perfusion with normal saline, enrofloxacin, PBD-1 82 μg·mL－1 and PBD-1 164 μg·mL－1 after infected with E.coli 13-1, respectively. Ⅰ. Blank control"

Fig. 9

Bacteria counts of mammary glands of mice mastitis treated by recombinant PBD-1 **** presents P < 0.000 1, * presents P < 0.05"