School of Industrial Technology, Universiti Sains Malaysia, 11800 USM, Panang, Malaysia.
J Dairy Sci. 2010 Apr;93(4):1383-92. doi: 10.3168/jds.2009-2574.
Fifteen strains of Lactobacillus and Bifidobacterium were screened based on their ability to adhere to hydrocarbons via the determination of cellular hydrophobicity. Lactobacillus acidophilus ATCC 314, L. acidophilus FTCC 0291, Lactobacillus bulgaricus FTCC 0411, L. bulgaricus FTDC 1311, and L. casei ATCC 393 showed greater hydrophobicity and, thus, were selected for examination of cholesterol-removal properties. All selected strains showed changes in cellular fatty acid compositions, especially total fatty acids and saturated and unsaturated fatty acids in the presence of cholesterol compared with those grown in the absence of cholesterol. In addition, we found that cells grown in media containing cholesterol were more resistant to sonication and enzymatic lysis compared with those grown without cholesterol. We further evaluated the location of the incorporated cholesterol via the insertion of fluorescence probes into the cellular membrane. In general, enrichment of cholesterol was found in the regions of the phospholipid tails, upper phospholipids, and polar heads of the cellular membrane phospholipid bilayer. Our results also showed that lactobacilli were able to reduce cholesterol via conversion of cholesterol to coprostanol, aided by the ability of strains to produce cholesterol reductase. Our results provided experimental evidence to strengthen the hypothesis that probiotics could remove cholesterol via the incorporation of cholesterol into the cellular membrane and conversion of cholesterol to coprostanol. The strains studied may be potential health adjunct cultures in fermented dairy products with possible in vivo hypocholesterolemic effects.
通过测定细胞疏水性，从 15 株乳杆菌和双歧杆菌中筛选出具有附着在碳氢化合物上的能力的菌株。嗜酸乳杆菌 ATCC 314、嗜酸乳杆菌 FTCC 0291、保加利亚乳杆菌 FTCC 0411、保加利亚乳杆菌 FTDC 1311 和干酪乳杆菌 ATCC 393 表现出更高的疏水性，因此被选中用于研究其去除胆固醇的特性。所有选定的菌株的细胞脂肪酸组成都发生了变化，特别是在存在胆固醇的情况下，总脂肪酸以及饱和脂肪酸和不饱和脂肪酸与在不存在胆固醇的情况下相比有所变化。此外，我们发现与在不含胆固醇的培养基中生长的细胞相比，在含有胆固醇的培养基中生长的细胞对超声处理和酶裂解更具抗性。我们进一步通过将荧光探针插入细胞膜来评估掺入的胆固醇的位置。一般来说，胆固醇在细胞膜磷脂双分子层的磷脂尾部、上层磷脂和极性头部区域富集。我们的结果还表明，乳杆菌通过将胆固醇转化为粪甾醇，从而降低胆固醇，这得益于菌株产生胆固醇还原酶的能力。我们的结果提供了实验证据，加强了益生菌可以通过将胆固醇掺入细胞膜并将胆固醇转化为粪甾醇来去除胆固醇的假设。所研究的菌株可能是发酵乳制品中潜在的健康辅助培养物，具有体内降胆固醇的潜在作用。
