Shao Dongyan, Yao Linbo, Riaz Muhammad Shahid, Zhu Jing, Shi Junling, Jin Mingliang, Huang Qingsheng, Yang Hui
Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 Youyi West Road, Xi'an, Shaanxi, 710072, China.
State Key Laboratory of Crop Stress Biology in Arid Area, College of Life Sciences, Northwest A & F University, 28 Xinong Road, Yangling, Shaanxi, 712100, China.
Appl Microbiol Biotechnol. 2017 Apr;101(8):3439-3449. doi: 10.1007/s00253-016-8059-6. Epub 2016 Dec 24.
The effects of weightlessness on enteric microorganisms have been extensively studied, but have mainly been focused on pathogens. As a major component of the microbiome of the human intestinal tract, probiotics are important to keep the host healthy. Accordingly, understanding their changes under weightlessness conditions has substantial value. This study was carried out to investigate the characteristics of Lactobacillus acidophilus, a typical probiotic for humans, under simulated microgravity (SMG) conditions. The results revealed that SMG had no significant impact on the morphology of L. acidophilus, but markedly shortened its lag phase, enhanced its growth rate, acid tolerance ability up to pH < 2.5, and the bile resistance at the bile concentration of <0.05%. SMG also decreased the sensitivity of L. acidophilus to cefalexin, sulfur gentamicin, and sodium penicillin. No obvious effect of SMG was observed on the adhesion ability of L. acidophilus to Caco-2 cells. Moreover, after SMG treatment, both the culture of L. acidophilus and its liquid phase exhibited higher antibacterial activity against S. typhimurium and S. aureus in a time-dependent manner. The SMG treatment also increased the in vitro cholesterol-lowering ability of L. acidophilus by regulating the expression of the key cholesterol metabolism genes CYP7A1, ABCB11, LDLR, and HMGCR in the HepG2 cell line. Thus, the SMG treatment did have considerable influence on some biological activities and characteristics of L. acidophilus related to human health. These findings provided valuable information for understanding the influence of probiotics on human health under simulated microgravity conditions, at least.
失重对肠道微生物的影响已得到广泛研究，但主要集中在病原体上。作为人类肠道微生物群的主要组成部分，益生菌对于维持宿主健康至关重要。因此，了解它们在失重条件下的变化具有重要价值。本研究旨在探讨典型的人类益生菌嗜酸乳杆菌在模拟微重力（SMG）条件下的特性。结果表明，SMG对嗜酸乳杆菌的形态没有显著影响，但明显缩短了其迟缓期，提高了其生长速率、在pH<2.5时的耐酸性能力以及在胆汁浓度<0.05%时的耐胆汁性。SMG还降低了嗜酸乳杆菌对头孢氨苄、硫酸庆大霉素和青霉素钠的敏感性。未观察到SMG对嗜酸乳杆菌与Caco-2细胞的黏附能力有明显影响。此外，经过SMG处理后，嗜酸乳杆菌培养物及其液相均对鼠伤寒沙门氏菌和金黄色葡萄球菌表现出随时间变化的更高抗菌活性。SMG处理还通过调节HepG2细胞系中关键胆固醇代谢基因CYP7A1、ABCB11、LDLR和HMGCR的表达，提高了嗜酸乳杆菌的体外降胆固醇能力。因此，SMG处理确实对嗜酸乳杆菌与人类健康相关的一些生物学活性和特性有相当大的影响。这些发现至少为理解模拟微重力条件下益生菌对人类健康的影响提供了有价值的信息。
