2026-03-10 シンガポール国立大学（NUS）
＜関連情報＞
- https://news.nus.edu.sg/natural-compound-fights-norovirus-infection/
- https://www.sciencedirect.com/science/article/abs/pii/S0740002025002503
プロバイオティクスBacillus subtilis CU1が産生するレバンは、高親和性結合を介してゼブラフィッシュにおけるヒトノロウイルスGII.4の複製を阻害する Levan produced by probiotic Bacillus subtilis CU1 inhibits human norovirus GII.4 replication in zebrafish via high-avidity binding
Siyu Chen, Malcolm Turk Hsern Tan, Jillinda Yi Ling Toh, Hong Bai, Qian Hua, Yu Keung Mok, Wenkang Wang, Shiguo Chen, Dan Li
Food Microbiology Available online: 25 October 2025
DOI:https://doi.org/10.1016/j.fm.2025.104970
Highlights
- The EPS produced by B. subtilis CU1 demonstrated antiviral potential against hNoV.
- The antiviral activity was primarily attributed to the inhibition of hNoVs binding rather than immune modulation.
- The major EPS component was purified and identified as a levan, which exhibited high binding affinity to hNoV GII.4.
- Carrot juice is a safe, cost-effective substrate for scalable EPS production via fermentation with B. subtilis CU1.
Abstract
This study investigated the antiviral potential of exopolysaccharides (EPSs) from probiotic bacteria against human noroviruses (hNoVs). EPSs from Bacillus subtilis CU1, B. subtilis R0179, and Lactiplantibacillus plantarum 299V were initially evaluated using Tulane virus (TV), a cultivable hNoV surrogate. Although EPSs reduced the cytopathic effects caused by TV infection, no clear dose-response relationship was observed. In contrast, the zebrafish model enabled testing of hNoV strains and revealed a distinct anti-hNoV GII.4 activity specific to EPS from B. subtilis CU1. This effect was virus genotype- and bacteria strain-specific: EPSs from B. subtilis R0179 and L. plantarum 299V showed no activity, nor did CU1 EPS affect hNoV GII.2 or GII.17. The major EPS fraction was identified as a levan composed of β-(2,6)-linked Fruf, which exhibited high binding affinity to hNoV GII.4 virus-like particles and P particles, confirmed by saliva-binding ELISA and bio-layer interferometry. Finally, B. subtilis CU1 was used to ferment carrot juice. The antiviral effect of EPS produced by B. subtilis CU1 in fermented carrot juice was validated, and the EPS yield was optimized accordingly. These findings highlight B. subtilis CU1 EPS as a promising anti-hNoVs agent and demonstrate carrot juice as a safe, cost-effective substrate for scalable production of functional probiotic EPSs.
