Eucommia ulmoides Oliv. has been extensively studied for its promoting effect on bacterial growth. A bacterial strain, called EU01, was isolated from the aqueous extract of E. ulmoides Oliv. leaves (AEEL). The optimal concentration of AEEL for promoting EU01 was 5 mg/ml, and the optimal cultivating time was 24 h. According to biochemical and physiological tests and genomic analysis, EU01 was identified as a Streptococcus thermophilus strain with probiotic potential. Strain EU01 showed strong inhibition against Staphylococcus aureus, which was also enhanced by 5 mg/ml AEEL. As such, the inhibitory spectrum and antimicrobial activity of strain EU01 with AEEL were investigated via the Oxford cup method. The transcriptome of strain EU01 was sequenced to explore the mode of action of AEEL on this strain. Among differentially expressed genes (DEGs) responding to AEEL, 66 genes were upregulated, and 229 genes were downregulated. DNA repaired and synthesis related functions were further demonstrated as remarkable differences through gene ontology (GO) and functional pathway analysis, especially associated with probiotic potential. This study suggested that traditional Chinese medicine (TCM) E. ulmoides promoting bacteria with probiotic potential might be a novel target for the treatment of diseases by regulating the intestinal flora.
Keywords
Eucommia ulmoides Oliv., probiotic potential, transcriptome, DNA repaired and synthesis related functions