嗜酸乳杆菌同化吸附降胆固醇作用机理研究
Study on cholesterol-lowering mechanism of Lactobacillus acidophilus by adsorbing and assimilating cholesterol
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摘要: 嗜酸乳杆菌具有降低血清及培养介质中胆固醇水平能力,其机理主要体现在其对胆固醇的吸附作用和同化吸收作用。实验采用MATH法测定了胆固醇介导嗜酸乳杆菌La-XH1和La-XH2表面疏水性、对超声波的抗性及胞内脂肪酸组成变化。结果表明,La-XH1和La-XH2对正十六烷和二甲苯具有较强表面疏水性,并通过电镜扫描结果显示,La-XH1和La-XH2可以将胆固醇吸附到自身表面,并随菌体一起在离心条件下沉淀下来,而且生长在含有胆固醇培养基内的菌株对超声波的抗性要明显高于生长在普通MRS培养基内的菌株。胞内脂肪酸含量GC-MC分析得出,添加胆固醇后,嗜酸乳杆菌La-XH1和La-XH2胞内饱和脂肪酸相对含量分别由16.99%与18.31%下降为13.55%与17.87%,不饱和脂肪酸相对含量分别由33.69%与32.22%增加至53.73%与53.91%,改变了菌体自身脂肪酸组成,胆固醇被菌体吸收同化到菌体内。Abstract: Lactobacillus acidophilus has the capacity of cholesterol- lowering in serum and cultivate media and its mechanism mainly embodies in adsorbing and assimilating cholesterol. By using MATH method, the surface hydrophobicity, resistance to ultrasonic and composition change of cellaur fatty acid mediated by cholesterol of La-XH1 and La-XH2, were measured.The results showed that La- XH1 and La- XH2 both had stronger surface hydrophobicity to hexadecane and xylol.Scanning electron microscope showed that La- XH1 and La- XH2 could adsorb cholesterol to its surface and deposit with thallus in centrifugal condition.In addition, strain in cultivate media including cholesterol had notable anti-ultrasonic resistance compared with that grown in common MRS cultivate.GC-MC analysis found that the relative amount of celluar saturated fatty acid of Lactobacillus acidophilus La-XH1 and La-XH2 had respectively declined to 13.55% and 17.87% from 16.99% and 18.31%, and the relative amount of unsaturated fatty acid respectively rose to 53.73% and 53.91% from 33.69% and 32.22%, which changed the composition of its own cellaur fatty acid and cholesterol had been adsorbed and assimilated into its thallus.
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