Objectives Probiotics ( Bacillus subtilis 04178) were entrapped in alginate-chitosan microcapsules by high-voltage electrostatic process. The encapsulation pattern was established as entrapped low density cells with culture (ELDC wc ). The performance of ELDC wc cells was investigated against stress environments of simulated digestive fluids. Results After incubation in simulated gastric (pH 2.5) and intestinal fluids (4% bile salt) for 2 h, the survival rate of ELDC wc cells (18.19% and 27.54%) was significantly higher than that of the free cells (0.0000009% and 0.0005%). The reason why B. subtilis embedded in microcapsules can resist the stress environments was that the mass production of extracellular proteins and polysaccharides prompted B. subtilis to form cell aggregates. The production of extracellular proteins and polysaccharides were regulated by the concentration of c-di-GMP and the expression of ydaJKLMN operon, abbA , sinI , slrA , slrB , abrR and sinR . Conclusions c-di-GMP is important for the production of extracellular polymer substance to enhance probiotic viability in stress environments.

中文翻译：

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c-di-GMP提高海藻酸盐-壳聚糖微囊化枯草芽孢杆菌细胞在模拟消化液中抗逆性的作用

目的通过高压静电过程将益生菌（枯草芽孢杆菌 04178）包裹在藻酸盐-壳聚糖微胶囊中。封装模式被建立为带有培养物的包埋低密度细胞（ELDC wc ）。针对模拟消化液的压力环境研究了 ELDC wc 细胞的性能。结果在模拟胃液（pH 2.5）和肠液（4%胆盐）中培养2 h后，ELDC wc细胞的存活率（18.19%和27.54%）显着高于游离细胞（0.0000009%和0.0000009%）。 0.0005%）。嵌入微胶囊中的枯草芽孢杆菌之所以能抵抗压力环境，是因为细胞外蛋白和多糖的大量产生促使枯草芽孢杆菌形成细胞聚集体。胞外蛋白和多糖的产生受c-di-GMP浓度和ydaJKLMN操纵子、abbA、sinI、slrA、slrB、abrR和sinR表达的调控。结论 c-di-GMP 对细胞外聚合物的产生很重要，以增强益生菌在应激环境中的生存能力。