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首页> 外文期刊>Applied Microbiology >Modification of the Technical Properties of Lactobacillus johnsonii NCC 533 by Supplementing the Growth Medium with Unsaturated Fatty Acids
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Modification of the Technical Properties of Lactobacillus johnsonii NCC 533 by Supplementing the Growth Medium with Unsaturated Fatty Acids

机译：通过向生长培养基中添加不饱和脂肪酸来修饰约翰逊乳杆菌NCC 533的技术特性

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The aim of this study was to investigate the influence of supplementing growth medium with unsaturated fatty acids on the technical properties of the probiotic strain Lactobacillus johnsonii NCC 533, such as heat and acid tolerance, and inhibition of Salmonella enterica serovar Typhimurium infection. Our results showed that the membrane composition and morphology of L. johnsonii NCC 533 were significantly changed by supplementing a minimal Lactobacillus medium with oleic, linoleic, and linolenic acids. The ratio of saturated to unsaturated plus cyclic fatty acids in the bacterial membrane decreased by almost 2-fold when minimal medium was supplemented with unsaturated fatty acids (10 μg/ml). The subsequent acid and heat tolerance of L. johnsonii decreased by 6- and 20-fold when the strain was grown in the presence of linoleic and linolenic acids, respectively, compared with growth in oleic acid (all at 10 μg/ml). Following acid exposure, significantly higher ( P < 0.05) oleic acid content was detected in the membrane when growth medium was supplemented with linoleic or linolenic acid, indicating that saturation of the membrane fatty acids occurred during acid stress. Cell integrity was determined in real time during stressed conditions using a fluorescent viability kit in combination with flow cytometric analysis. Following heat shock (at 62.5°C for 5 min), L. johnsonii was unable to form colonies; however, 60% of the bacteria showed no cell integrity loss, which could indicate that the elevated heat inactivated vital processes within the cell, rendering it incapable of replication. Furthermore, L. johnsonii grown in fatty acid-enriched minimal medium had different adhesion properties and caused a 2-fold decrease in S. enterica serovar Typhimurium UK1-lux invasion of HT-29 epithelial cells compared with bacteria grown in minimal medium alone. This could be related to changes in the hydrophobicity and fluidity of the membrane. Our study shows that technical properties underlying probiotic survivability can be affected by nutrient composition of the growth medium.
机译：本研究的目的是研究用不饱和脂肪酸补充生长培养基对益生菌约翰逊乳杆菌NCC 533的技术性能（如耐热和耐酸）以及抑制肠炎沙门氏菌鼠伤寒沙门氏菌感染的影响。我们的结果表明，通过添加油酸，亚油酸和亚麻酸，在最小限度的乳酸杆菌培养基中，约翰逊氏乳杆菌NCC 533的膜组成和形态发生了显着变化。当在基本培养基中添加不饱和脂肪酸（10μg/ ml）时，细菌膜中饱和脂肪酸与不饱和脂肪酸和环状脂肪酸的比率几乎降低了2倍。当菌株在亚油酸和亚麻酸存在下分别生长时，其随后的耐酸和耐热性分别降低了6倍和20倍，而油酸则是10μg/ ml。酸暴露后，当生长培养基中添加亚油酸或亚麻酸时，在膜中检测到明显更高的（P <0.05）油酸含量，表明在酸胁迫期间发生了膜脂肪酸饱和。使用荧光活力试剂盒结合流式细胞仪分析实时确定应激条件下的细胞完整性。热冲击后（在62.5°C持续5分钟），约翰逊乳杆菌无法形成菌落。然而，有60％的细菌没有显示出细胞完整性的损失，这可能表明热量升高使细胞内的重要过程失活，使其无法复制。此外，与仅在基本培养基中生长的细菌相比，在富含脂肪酸的基本培养基中生长的约翰逊乳酸菌具有不同的粘附特性，并导致HT.29上皮细胞肠球菌血清鼠伤寒病毒UK1-lux对HT-29上皮细胞的侵袭减少了2倍。这可能与膜的疏水性和流动性的变化有关。我们的研究表明，益生菌生存能力的技术特性可能会受到生长培养基营养成分的影响。

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