Extraction of Antimicrobial Peptides from Periplaneta americana and Their Effects on Antibacterial Activity of Different Pathogenic Bacteria
This experiment was conducted to explore the optimal extraction time of antimicrobial Peptides from Periplaneta americana and their effects on antibacterial activity of different pathogenic bacteria.A total of 100 Periplaneta americana were randomly divided into 2 groups with 5 replicates per group and 10 Periplaneta a-mericana per replicate.The experiment used Escherichia coli as the inducer to induce the production of antimi-crobial peptides from Periplaneta americana,the induction group was injected with 1 µL 1×108 CFU/kg Esch-erichia coli,while the control group was injected with 1 μL physiological saline,the antimicrobial peptides from Periplaneta americana were extracted at 12,24,36,48,60 and 72 h after induction,respectively.The molecular weight of antimicrobial peptides from Periplaneta americana was determined by sodium dodecyl sul-fate-polyacrylamide gel electrophoresis(SDS-PAGE)test,the protein concentration of extracting solution of antimicrobial peptides from Periplaneta americana was determined by BCA kit,the antibacterial activity of ex-tracting solution of antimicrobial peptides from Periplaneta americana was determined by the drug sensitive tab-let method,and the minimum inhibitory concentration(MIC),thermal stability,pH stability and repeated freeze-thaw stability were also determined.The results showed as follows:1)the molecular weight of the anti-microbial peptides from Periplaneta americana was about 7.5 ku.After induction at 12,24,36,48,60 and 72 h,the protein concentration of extracting solution of antimicrobial peptides from Periplaneta americana of induction group was significantly higher than that of the control group(P＜0.01),the protein concentration of extracting solution of antimicrobial peptides from Periplaneta americana after induction at 48 h was the high-est,therefore,selected the antimicrobial peptides from Periplaneta americana after induction at 48 h for the subsequent antibacterial tests.2)Compared with the control group,the diameter of antibacterial circle of Esch-erichia coli,Salmonella and Staphylococcus aureus of induction group was significantly increased(P＜0.01).The antimicrobial peptides from Periplaneta americana minimum inhibitory concentration against Escherichia coli was 1.0 mg/L,the minimum inhibitory concentration against Salmonella was 3.0 mg/L,and the minimum inhibitory concentration against Staphylococcus aureus was 2.5 mg/L.3)Compared with the control group,the diameter of antibacterial circle of extracting solution of antimicrobial peptides from Periplaneta americana after heating in water baths at 75,85,95 and 100 ℃ was significantly decreased(P＜0.05),the diameter of antibacterial circle of extracting solution of antimicrobial peptides from Periplaneta americana after freeze-thaw 2,4,6,8 and 10 times was significantly decreased(P＜0.05),and the diameter of antibacterial circle of ex-tracting solution of antimicrobial peptides from Periplaneta americana after treatment with solutions with pH of 1,3,7,9 and 11 was significantly decreased(P＜0.05).In conclusion,the 48 h after Escherichia coli induc-tion is the optimal extraction time for antimicrobial peptides from Periplaneta americana,which has the charac-teristics of high concentration,strong thermal stability and acid and alkali resistance.[Chinese Journal of Ani-mal Nutrition,2024,36(9):6072-6082]
antimicrobial peptides from Periplaneta americanaantibacterial activityEscherichia coliSal-monellaStaphylococcus aureus
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