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標題: 牛乳鐵蛋白對大腸桿菌與幽門螺旋桿菌抗菌作用之探討
The antibiotic effect of bovine lactoferrin on Escherichia coli and Helicobacter pylori
作者: 曹李宏
關鍵字: lactoferrin;乳鐵蛋白;Escherichia coli;Helicobacter pylori;大腸桿菌;幽門螺旋桿菌
出版社: 獸醫微生物學研究所
本研究在分析乳鐵蛋白之抗菌能力,並探討其可能的抗菌機制。實驗結果顯示,乳鐵蛋白可有效的抑制引起仔豬嚴重下痢的大腸桿菌,亦可抑制引起胃、十二指腸潰瘍的幽門螺旋桿菌之生長。乳鐵蛋白濃度須達25 μM始有明顯抑制細菌生長的作用,若乳鐵蛋白濃度降低,此抑制細菌生長的作用也會逐漸消失,而乳鐵蛋白抑制細菌生長的作用可被環境中過量的鐵離子所終止。在實驗中並比較運鐵蛋白、儲鐵蛋白與乳鐵蛋白的抗菌能力,這些同樣可以與鐵離子結合的蛋白,均有抑制大腸桿菌生長之作用,也說明了乳鐵蛋白可透過與細菌競爭鐵離子而達到抑制細菌之作用。此外,在培養基加入大量死菌的情況下,乳鐵蛋白抑制細菌生長之作用也隨之消失,因而推論乳鐵蛋白亦可透過與細菌發生直接作用,而達到抑制細菌生長的功能。

Lactoferrin is an antimicrobial iron-binding glycoprotein, and the molecular weight is about 80 kDa. It is found in most mucous secretion of mammals including milk, saliva, tears, and released from activated neutrophil in the inflammatory response. The antibacterial activity and the possible mechanism of lactoferrin was studied. The results showed that lactoferrin could effectively inhibit the growth of 5 strains of E. coli that cause severe diarrhea of piglets, and 9 strains of H. pylori that cause gastrointestine disease. The effective dose of lactoferrin for antibacterial activity was 25M. We also found that this antibacterial effect would be blocked by excess of iron. In comparison of apo-transferrin, apo-ferritin, and lactoferrin showed similar activity of inhibition of E. coli. This comes to a conclusion that the inhibition effect is caused by the competition of iron in LB medium. Furthermore, we also found that in the surrounding of outer membrane from dead bacteria, the antibacterial activity of lactoferrin was diminished. Therefore we also believed that lactoferrin may act directly on the outer membrane to inhibit the gram negative bacteria growth.
Appears in Collections:微生物暨公共衛生學研究所

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