Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
Laboratory for Animal Nutrition and Product Quality (LANUPRO), Ghent University, Proefhoevestraat 10, 9090 Melle, Belgium.
Benef Microbes. 2013 Dec 1;4(4):299-312. doi: 10.3920/BM2013.0017.
Lactobacillus reuteri is a commensal, beneficial gut microbe that colonises the intestinal mucus layer, where it makes close contact with the human host and may significantly affect human health. Here, we investigated the capacity of linoleic acid (LA), the most common polyunsaturated fatty acid (PUFA) in a Western-style diet, to affect L. reuteri ATCC PTA 6475 prevalence and survival in a simulated mucus layer. Short-term (1 h) survival and mucin-agar adhesion assays of a log-phase L. reuteri suspension in intestinal water demonstrated that the simulated mucus layer protected L. reuteri against the inhibitory effects of LA by lowering its contact with the bacterial cell membrane. The protective effect of the simulated mucus layer was further evaluated using a more complex and dynamic model of the colon microbiota (SHIME®), in which L. reuteri survival was monitored during 6 days of daily exposure to LA in the absence (L-SHIME) and presence (M-SHIME) of a simulated mucus layer. After 6 days, luminal L- and M-SHIME L. reuteri plate counts had decreased by 3.1±0.5 and 2.6±0.9 log cfu/ml, respectively. Upon supplementation of 1.0 g/l LA, the decline in the luminal L. reuteri population started earlier than was observed for the control. In contrast, mucin-agar levels of L. reuteri (in the M-SHIME) remained unaffected throughout the experiment even in the presence of high concentrations of LA. Overall, the results of this study indicate the importance of the mucus layer as a protective environment for beneficial gut microbes to escape from stress by high loads of the antimicrobial PUFA LA to the colon, i.e. due to a Western-style diet.
罗特氏乳杆菌是一种共生有益肠道微生物，定植于肠道黏液层，与人类宿主密切接触，可能对人类健康产生重大影响。在这里，我们研究了亚油酸（LA）作为西方饮食中最常见的多不饱和脂肪酸（PUFA）对罗特氏乳杆菌 ATCC PTA 6475 在模拟黏液层中丰度和存活的影响。在肠道水中对数期罗特氏乳杆菌悬浮液的短期（1 h）存活和黏蛋白琼脂黏附试验表明，模拟黏液层通过降低其与细菌细胞膜的接触来保护罗特氏乳杆菌免受 LA 的抑制作用。通过更复杂和动态的结肠微生物群模型（SHIME®）进一步评估了模拟黏液层的保护作用，其中在不存在（L-SHIME）和存在（M-SHIME）模拟黏液层的情况下，每天监测罗特氏乳杆菌在 LA 中的 6 天生存情况。6 天后，腔室 L-和 M-SHIME 罗特氏乳杆菌平板计数分别减少了 3.1±0.5 和 2.6±0.9 log cfu/ml。在补充 1.0 g/L LA 后，与对照相比，腔室罗特氏乳杆菌种群的下降更早开始。相比之下，即使在存在高浓度 LA 的情况下，M-SHIME 中的黏蛋白琼脂水平的罗特氏乳杆菌（仍）未受影响。总的来说，这项研究的结果表明，黏液层作为有益肠道微生物的保护环境的重要性，使其能够逃避高负荷的抗菌 PUFA LA 对结肠的应激，即由于西方饮食。
