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Enteric viruses exploit bacterial components, including lipopolysaccharides (LPS) and peptidoglycan (PG), to facilitate infection in humans. Because of their origin in the bat enteric system, we wondered if severe acute respiratory syndrome coronavirus (SARS-CoV) or Middle East respiratory syndrome CoV (MERS-CoV) also use bacterial components to modulate infectivity. To test this question, we incubated CoVs with LPS and PG and evaluated infectivity, finding no change following LPS treatment. However, PG from Bacillus subtilis reduced infection Ͼ10,000-fold, while PG from other bacterial species failed to recapitulate this. Treatment with an alcohol solvent transferred inhibitory activity to the wash, and mass spectrometry revealed surfactin, a cyclic lipopeptide antibiotic, as the inhibitory compound. This antibiotic had robust dose-and temperature-dependent inhibition of CoV infectivity. Mechanistic studies indicated that surfactin disrupts CoV virion integrity, and surfactin treatment of the virus inoculum ablated infection in vivo. Finally, similar cyclic lipopeptides had no effect on CoV infectivity, and the inhibitory effect of surfactin extended broadly to enveloped viruses, including influenza, Ebola, Zika, Nipah, chikungunya, Una, Mayaro, Dugbe, and Crimean-Congo hemorrhagic fever viruses. Overall, our results indicate that peptidoglycan-associated surfactin has broad viricidal activity and suggest that bacteria by-products may negatively modulate virus infection. IMPORTANCE In this article, we consider a role for bacteria in shaping coronavirus infection. Taking cues from studies of enteric viruses, we initially investigated how bacterial surface components might improve CoV infection. Instead, we found that peptidoglycan-associated surfactin is a potent viricidal compound that disrupts virion integrity with broad activity against enveloped viruses. Our results indicate that interactions with commensal bacterial may improve or disrupt viral infections, highlighting the importance of understanding these microbial interactions and their implications for viral pathogenesis and treatment.

1Enteric viruses exploit bacterial components including lipopolysaccharides (LPS) and 2 peptidoglycan (PG) to facilitate infection in humans. With origins in the bat enteric system, we 3 wondered if severe acute respiratory syndrome-coronavirus (SARS-CoV) or Middle East 4 respiratory syndrome-CoV (MERS-CoV) also use bacterial components to modulate infectivity. 5To test this question, we incubated CoVs with LPS and PG and evaluated infectivity finding no 6 change following LPS treatment. However, PG from B. subtilis reduced infection >10,000-fold 7 while PG from other bacterial species failed to recapitulate this. Treatment with an alcohol 8 solvent transferred inhibitory activity to the wash and mass spectrometry revealed surfactin, a 9 cyclic lipopeptide antibiotic, as the inhibitory compound. This antibiotic had robust dose-and 1 0 temperature-dependent inhibition of CoV infectivity. Mechanistic studies indicated that surfactin 1 1 disrupts CoV virion integrity and surfactin treatment of the virus inoculum ablated infection in 1 2 vivo. Finally, similar cyclic lipopeptides had no effect on CoV infectivity and the inhibitory effect

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Cucurbitane-type triterpenoids such as mogrosides and cucurbitacins that are present in the plants of Cucurbitaceae are widely used in Asian traditional medicine. Cucurbitadienol is the skeleton of cucurbitane-type triterpenoids. As an alternative production strategy, we developed baker’s yeast Saccharomyces cerevisiae as a microbial host for the eventual transformation of cucurbitadienol. The synthetic pathway of cucurbitadienol was constructed in Saccharomyces cerevisiae by introducing the cucurbitadienol synthase gene from different plants, resulting in 7.80 mg cucurbitadienol from 1 L of fermentation broth. Improving supplies of isoprenoid precursors was then investigated for increasing cucurbitadienol production. Cucurbitadienol production increased to 21.47 mg/L through the overexpression of a global regulatory factor (UPC2) gene of triterpenoid synthase. In addition, knockout of the ERG7 gene increased cucurbitadienol production from 21.47 to 61.80 mg/L. Finally, fed-batch fermentation was performed, and 63.00 mg/L cucurbitadienol was produced. This work is an important step towards the total biosynthesis of valuable cucurbitane-type triterpenoids and demonstrates the potential for developing a sustainable and secure yeast biomanufacturing platform for triterpenoids.

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ZSP can block the development from SEED I and SEED II to EC by 47.79%. Efforts should be made to screen and treat dysplasia cases in people aged 40 years and older in high risk areas to reduce the mortality figures.