五谷虫蛋白粗提液对牛源致病性Escherichia coli O_1和E.coli O_(78)体外抑菌作用

Antibacterial effects of crude protein ectract from maggot on bovine pathogenic Escherichia coli O_1 and E.coli O_(78)

为研究五谷虫蛋白粗提液对Escherichia coli O_1和E.coli O_(78)的体外抑菌作用,采用试剂盒测定五谷虫粗提液蛋白含量;牛津杯法测定蛋白粗提液对牛源病源性E.coli O_1和E.coli O_(78)的抑菌圈直径;通过二倍稀释法测定蛋白粗提液对2种细菌的最低抑菌浓度(MIC);平板法测定最低杀菌浓度(MBC);酶标比浊法测定粗提液对2种细菌的24h生长曲线、细胞膜通透性以及碱性磷酸酶(AKP)的含量。研究表明:1)五谷虫蛋白粗提液蛋白质量浓度为0.680mg/mL;粗提液对E.coli O_1和E.coli O_(78)的抑菌圈直径分别为(25.09±0.62)和(20.96±0.48)mm,MIC分别为15.625和31.250mg/mL,MBC为62.5和125mg/mL,传统中药水煎剂和提取缓冲液没有体外抑菌效果。2)粗提液能影响E.coli O_1和E.coli O_(78)的生长曲线,增加细菌细胞膜和细胞壁通透性。由此可见,蛋白粗提液对E.coli O_1和E.coli O_(78)均有体外抑菌效果,且对E.coli O_1的体外抑菌效果优于E.coli O_(78)。

To study the antibacterial mechanism of crude protein extract,which is aquired from Chinese medicine,on bovine pathogenic Escherichia coli O1 and E. coli O78.The content of crude protein extract from maggot was determined by enhanced BCA Protein Assay Kit.The diameters of inhibition zone on bovine E. coli O1 and E. coli O78 were determined by Oxford cup method;The MIC of crude protein extract for two bacteria was determined by two dilution methods.The MBC was determined by plate method.To investigate the antibacterial effects of crude protein extract to against the two bacteria,turbidimetry was adopted to measure 24 h growth curve,cell membrane permeability and the content of AKP. The result showed that：1）The concentration of crude protein extract from Maggot was 0.680 mg/mL;The diameters of inhibition zone of E. coli O1 and E. coli O78 were （25.09±0.62）and （20.96±0.48） mm respectively;Their MICs were 15.625 and 31.250 mg/mL respectively;MBCs were 62.5 and 125 mg/mL;The traditional Chinese medicine decoction and the extracting buffer didn＇t display any antibacterial effects in vitro;2）The crude extract effected the growth curve of both E. coli O1 and E. coli O78,also increased the permeability of cell membrane and cell wall.In conclusion,the crude protein extract of maggot have antibacterial effects on both E. coli O1 and E. coli O78,and the antibacterial effects in vitro on E. coli O1 is better than E. coli O78.