The Antibacterial Activity Research Of Antimicrobial Peptide LL-37 And Antimicrobial Peptide CP1 And Theirs Application In The Milk Preservation

Antimicrobial peptides is universal existence in nature, with its had a high capacity and broad-spectrum antibacterial activity, and not only can kill Gram-positive bacteria, but also can well restrain Gram-negative bacteria, fungi and parasites. Its molecular structure is stable, and has low molecular weight and good water solubility. Its unlikely to remain vulnerable, uneasy to produce drug resistance in vivo metabolic. It is expected to develop in the field of medicine, food and animal husbandry etc. developing new drugs and become a new preservative.Antimicrobial pedites LL-37 is C-terminal fragment which was released after hCAP-18 broken down by enzymes, and its named because the first two N-terminal amino acid residue leucine(L) and a total of 37 amino acid residues. Cecropin CP1 was named because CecropinPl containing 31 amino acid residues, and its molecular weight is 3.3KD,Cysteine(Cys)-free, and can not form an intramolecular disulfide bonds. Its N-terminus had a strongly alkalinity, and C-terminus had strongly hydropHobic property. Its was isolated from parasites of porcine intestinal.The study of human antimicrobial pedites LL-37 and antimicrobial peptides CP1 ‘s antibacterial activity on microorganisms, as well as the influence of pHysical and chemical factors including pH value, temperature, heat treatment time in human antimicrobial pedites LL-37 inhibition of bacterial activity. Antimicrobial pedites LL-37 and antimicrobial pedites CP1 in rat lung cells(WTRL1) and human lung cancer cell line A549 cytotoxic by measured pass the way of CCK. And researched antimicrobial peptides LL-37 and antimicrobial peptides CP1 preliminary application in fresh milk preservation.The results show(1) Antimicrobial peptides has a strong inhibitory effect to foodborne microbes. The minimum inhibitory concentration of StapHylococcus aureus(ATCC29213) was 272 ug / mL. The antibacterial activity of antimicrobial peptides was best in pH 6.0. Antimicrobial peptides in 121 ℃ treatment 30 min, still had highly effective antibacterial activity, and storage best at-20 ℃. The recombinant cecropin P1 showed different degrees of bacteriostasis for these seven respiratory bacteria(2) Antimicrobial peditesLL-37 and antimicrobial peditesCP1 had no significant cytotoxicity to rat lung cells(WTRL1) and A549 human lung cancer cells. Its for antimicrobial peditesLL-37 and antimicrobial peptides CP1 use in food as a preservative provide evidence.(3) Added 0.25 g / kg amount antimicrobial peditesLL-37 and antimicrobial peditesCP1 in fresh milk, after detected,the total number of bacterial colony of its obviously under control. The rate of decrease pH value decreased, sensory status has been maintained, thus demonstrating antimicrobial peditesLL-37 and antimicrobial peditesCP1 are applied feasibility of fresh milk preservation.