The aim of this experiment was to clone and express the active substances that could inhibit the growth of Aspergillusflavus from Bacillus amyloliquefaciens B10,verify their inhibitory activity against As-pergillusflavus and clarify their antibacterial action mode.The experiment purified recombinant 1,3-1,4-β-D-glucan 4-glucan hydrolase(B10-Glu)and antibacterial peptide LCI(B10-LCI)through cloning,expression,affinity chromatography,and other operations,and analyzed their basic biological information.After verifying their antibacterial activity through plate antibacterial tests,investigate the effects of minimum inhibitory concen-tration(MIC)of Bl0-Glu and B10-LCI,as well as environmental conditions,on their antibacterial effects.The inhibition mode of Aspergillusflavus was explored by electron microscope observation,cell membrane per-meability,mitochondrial membrane potential change,reactive oxygen species(ROS)content and catalase(CAT),superoxide dismutase(SOD)activity detection.The results showed as follows:1)the apparent mo-lecular weights of B10-Glu and B10-LCI were 25 and 12 ku,respectively,which were close to the predicted molecular weights.The optimal induction conditions for B10-LCI were 16 ℃ for 16 h,and B10-Glu was 25 ℃for 12 h.2)Both B10-Glu and B10-LCI had obvious inhibitory effects on Aspergillusflavus,and the radius of inhibitory zone was 1.14 and 1.17 cm,respectively.MIC were 0.94 and 0.96 μg/mL,respectively 3)Both B10-Glu and B10-LCI could inhibit the formation of Aspergillusflavus spores;destroy its mycelial morphology and cellular internal structure;improving the membrane permeability of Aspergillusflavus cells,resulting in loss of cell content logistics;destroy organelle such as mitochondria,promote ROS accumulation and reduce cell antioxidant level.In summary,Bl0-Glu and B10-LCI can exert their excellent anti Aspergillusflavus effect by inhibiting the growth and reproduction of Aspergillusflavus and destroying its cell structure.[Chinese Journal of Animal Nutrition,2023,35(12):8024-8035]
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