食窦魏斯氏菌可促进肠道健康,增强宿主免疫应答,为选育出耐酸性强的食窦魏斯氏菌,该研究以从泡菜中筛选出的食窦魏斯氏菌W25为出发菌株,通过紫外诱变(ultraviolet,UV,60 s)、甲基磺酸乙酯(ethyl methylsulfone,EMS)诱变(0.5%,45 min)及...食窦魏斯氏菌可促进肠道健康,增强宿主免疫应答,为选育出耐酸性强的食窦魏斯氏菌,该研究以从泡菜中筛选出的食窦魏斯氏菌W25为出发菌株,通过紫外诱变(ultraviolet,UV,60 s)、甲基磺酸乙酯(ethyl methylsulfone,EMS)诱变(0.5%,45 min)及复合诱变UV-EMS和EMS-UV筛选获得U20、E7、U-E18和E-U28四株突变株。U-E18表现最优,产酸活力较W25显著提升;模拟胃肠环境耐受性,U-E18在pH 1.5胃液中存活率为20.92%,肠液环境中8 h存活率为13.78%,W25均完全失活;U-E18在8 h胆盐中生长率达32.48%,远高于W25的18.36%。功能基因组学分析揭示了U-E18的耐酸分子机制,蛋白质直系同源簇(cluster of orthologous groups of protein,COG)功能注释分析显示碳水化合物转运代谢、翻译及核糖体生物合成、氨基酸转运代谢等通路显著富集;KEGG通路分析鉴定出ABC转运蛋白系统具有关键作用。综上所述,U-E18为耐酸性强的优良菌株资源,为食品发酵的研究与应用提供了重要的候选菌株,具有广阔的开发潜力和应用前景。展开更多
Understanding the deterioration behaviors and mechanisms of rocks under thermo-hydromechanical(THM)interactions is crucial for mitigating slope instability.In this study,the physicomechanical properties of silty mudst...Understanding the deterioration behaviors and mechanisms of rocks under thermo-hydromechanical(THM)interactions is crucial for mitigating slope instability.In this study,the physicomechanical properties of silty mudstone subjected to THM interactions were investigated by triaxial tests.The underlying micro-mechanisms were revealed using microscopic tests.The triaxial test results indicate that the strength parameters of silty mudstone decrease by 89.50%(deformation modulus),78.15%(peak strength),70.58%(cohesion),and 48.65%(friction angle)under 16 THM cycles,a load of 300 kPa,and alternating between 0℃water immersion and 60℃drying.The SEM test results indicate that the deterioration of silty mudstone strength primarily results from hydrothermal-expansion softening and cracking driven by the TLHM interactions.The specimens manifest shear failure under confining pressure exceeding 140 kPa.Furthermore,a new constitutive model considering hydrothermalexpansion strain and non-linear deformation characteristics was developed.The discrepancy between the experimentally measured peak strength and the damage constitutive model prediction remains below 5%.The proposed model is verified to be in satisfactory agreement with the experimental results.The self-designed THM apparatus overcomes the limitations of traditional investigations,enabling simultaneous consideration of thermal,hydraulic,and mechanical interactions.展开更多
文摘食窦魏斯氏菌可促进肠道健康,增强宿主免疫应答,为选育出耐酸性强的食窦魏斯氏菌,该研究以从泡菜中筛选出的食窦魏斯氏菌W25为出发菌株,通过紫外诱变(ultraviolet,UV,60 s)、甲基磺酸乙酯(ethyl methylsulfone,EMS)诱变(0.5%,45 min)及复合诱变UV-EMS和EMS-UV筛选获得U20、E7、U-E18和E-U28四株突变株。U-E18表现最优,产酸活力较W25显著提升;模拟胃肠环境耐受性,U-E18在pH 1.5胃液中存活率为20.92%,肠液环境中8 h存活率为13.78%,W25均完全失活;U-E18在8 h胆盐中生长率达32.48%,远高于W25的18.36%。功能基因组学分析揭示了U-E18的耐酸分子机制,蛋白质直系同源簇(cluster of orthologous groups of protein,COG)功能注释分析显示碳水化合物转运代谢、翻译及核糖体生物合成、氨基酸转运代谢等通路显著富集;KEGG通路分析鉴定出ABC转运蛋白系统具有关键作用。综上所述,U-E18为耐酸性强的优良菌株资源,为食品发酵的研究与应用提供了重要的候选菌株,具有广阔的开发潜力和应用前景。
基金supported by“the National Natural Science Foundation of China(52378440,52078067,52078066,42477143,52408458)the Key Science and Technology Program in the Transportation Industry(2022-MS1-032,2022-MS5-125)+4 种基金the Natural Science Foundation of Hunan Province(2023JJ10045)the Outstanding Innovative Youth Training Program of Changsha City(kq2305023)Scientific Research Foundation of Hunan Provincial Education Department(24B0292)Water Resources Science and Technology Project of Hunan Province(XSKJ2023059-41)the Guangxi Key Research and Development Program(AB23075184)。
文摘Understanding the deterioration behaviors and mechanisms of rocks under thermo-hydromechanical(THM)interactions is crucial for mitigating slope instability.In this study,the physicomechanical properties of silty mudstone subjected to THM interactions were investigated by triaxial tests.The underlying micro-mechanisms were revealed using microscopic tests.The triaxial test results indicate that the strength parameters of silty mudstone decrease by 89.50%(deformation modulus),78.15%(peak strength),70.58%(cohesion),and 48.65%(friction angle)under 16 THM cycles,a load of 300 kPa,and alternating between 0℃water immersion and 60℃drying.The SEM test results indicate that the deterioration of silty mudstone strength primarily results from hydrothermal-expansion softening and cracking driven by the TLHM interactions.The specimens manifest shear failure under confining pressure exceeding 140 kPa.Furthermore,a new constitutive model considering hydrothermalexpansion strain and non-linear deformation characteristics was developed.The discrepancy between the experimentally measured peak strength and the damage constitutive model prediction remains below 5%.The proposed model is verified to be in satisfactory agreement with the experimental results.The self-designed THM apparatus overcomes the limitations of traditional investigations,enabling simultaneous consideration of thermal,hydraulic,and mechanical interactions.
