摘要:
使用MRS培养基,从新鲜牛乳中分离得到1株生长良好的乳酸菌(AR66),经菌落形态、细胞形态、生化反应实验,发现菌株能产乳酸、革兰氏染色阳性、接触酶阴性。经系统发育分析,确定菌株AR66为肠膜明串珠菌。肠膜明串珠菌AR66具有抗氧化活性,对羟自由基、DPPH和超氧阴离子的清除率与细胞浓度呈正相关。在细胞浓度为5×108CFU/m L时,未破碎细胞对羟自由基、超氧阴离子的清除率高于已破碎细胞的清除率,分别是49.76%和83.33%;已破碎细胞对DPPH自由基的清除率高于未破碎细胞的清除率,为77.09%。菌株AR66还具有清除培养基中44.73%的胆固醇。菌株AR66对我国未来益生菌功能食品的开发具有重要价值。
Abstract:
Using MRS media,one strain of lactic acid bacteria was isolated from milk. The strain could present Gram-positive,catalase-negative,non-spore,and produce lactic acid. The 16 S r DNA gene similarities(99.7%)between strain AR66 and its closest phylogenetic neighbor, Leuconostoc mesenteroides, were higher than those previously reported within the leuconostoc. So strain AR66 was identified as L.mesenteroides. Strain AR66 had the free radical-scavenging ability. Three free radicals-scavenging ratios of strain AR66 were positively correlated with bacterial density,respectively. At a concentration of 5 ×108CFU/m L,the scavenging ratios of intact cells on hydroxyl radical and superoxide radical were 49.76%,and 83.33% respectively,which demonstrated obvious higher than intracellular extract. However,at the same concentration,intracellular extract had better DPPH-scavenging effect(scavenging ratios 77.09%) than the intact cells. In addition,strain AR66 for 60 h had the ability of cholesterol-reducing(removal rate,44.73%). The study had important meaning to the exploitation of probiotic health.
百度学术
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