title: Simulated microgravity affects some biological characteristics of Lactobacillus acidophilus.
abstract: 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.
authors.affiliation: Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 Youyi West Road, Xi'an, Shaanxi, 710072, China.
authors.forename: Dongyan
authors.identifier: http://orcid.org/0000-0002-6420-4657
authors.initials: D
authors.lastname: Shao
authors.affiliation: 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.
authors.forename: Linbo
authors.initials: L
authors.lastname: Yao
authors.affiliation: Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 Youyi West Road, Xi'an, Shaanxi, 710072, China.
authors.forename: Muhammad Shahid
authors.initials: MS
authors.lastname: Riaz
authors.affiliation: Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 Youyi West Road, Xi'an, Shaanxi, 710072, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 Youyi West Road, Xi'an, Shaanxi, 710072, China. sjlshi2004@nwpu.edu.cn.
authors.forename: Junling
authors.initials: J
authors.lastname: Shi
authors.affiliation: Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 Youyi West Road, Xi'an, Shaanxi, 710072, China.
authors.forename: Mingliang
authors.initials: M
authors.lastname: Jin
authors.affiliation: Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 Youyi West Road, Xi'an, Shaanxi, 710072, China.
authors.forename: Qingsheng
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 Youyi West Road, Xi'an, Shaanxi, 710072, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001422:Bacterial Adhesion; D001647:Bile Acids and Salts / Q000494:pharmacology; D018938:Caco-2 Cells; D002784:Cholesterol / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007422:Intestines / Q000187:drug effects; D007779:Lactobacillus acidophilus / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology*; D019936:Probiotics / Q000378:metabolism; D013211:Staphylococcus aureus / Q000187:drug effects; D014893:Weightlessness; D018474:Weightlessness Simulation
chemical_list: D000900:Anti-Bacterial Agents; D001647:Bile Acids and Salts; D002784:Cholesterol
keywords: Characteristics; Cholesterol-lowering; Lactobacillus acidophilus; Probiotics; Simulated microgravity