In Vivo Characterization and Genome-based Approach to Lactobacillus Johnsonii Byun-jo-01 and Its Probiotic Properties

Abstract To develop new antiviral probiotics, bacteria were isolated from the microbiome in a murine intestine. In 16S rDNA sequence analysis, most isolates were identified as Lactobacillus johnsonii. These isolates were further assessed using whole-genome sequencing through the Illumina and PacBio platform, which revealed that the isolates were new strains. A novel probiotic strain, Lactobacillus johnsonii Byun-jo-01, was evaluated to determine its probiotic characteristics of safety, immune modulation, and antiviral efficacy against murine norovirus. Oral administration of L. johnsonii Byun-jo-01 was demonstrated to be safe in mice in terms of body weight, food intake, and bacterial translocation. Additionally, the expression levels of IFN-beta and IFN-gamma induced by L. johnsonii Byun-jo-01 in the small intestines of mice were higher than those in mice fed L. paracasei ATCC 334 and L. reuteri KACC 11452. Among the three different bacterial strains used in this study, L. johnsonii Byun-jo-01 showed the highest antiviral efficacy against murine norovirus, reducing the viral titer in fecal samples by 28 times compared with mice infected with murine norovirus. To support those in vivo experiments, genome-based data mining was performed to investigate which genes related to probiotic-specific markers were highly expressed in this isolate. Specifically, DnaK, GroEL, GroES, and GrpE, which are involved in the acid adaptation required to overcome the harsh in vivo condition, were highly expressed. Taken together, these results suggest that host-originated probiotics can be more effective than bacteria isolated from other sources, such as fermented food.