Characterization of a mouse-adapted strain of bat severe acute respiratory syndrome-related coronavirus.

Bats carry genetically diverse severe acute respiratory syndrome-related coronaviruses (SARSr-CoVs). Some of them utilize human angiotensin-converting enzyme 2 (hACE2) as a receptor and cannot efficiently replicate in wild-type mice. Our previous study demonstrated that the bat SARSr-CoV rRsSHC014S induces respiratory infection and lung damage in hACE2 transgenic mice but not wild-type mice. In this study, we generated a mouse-adapted strain of rRsSHC014S, which we named SMA1901, by serial passaging of wild-type virus in BALB/c mice. SMA1901 showed increased infectivity in mouse lungs and induced interstitial lung pneumonia in both young and aged mice after intranasal inoculation. Genome sequencing revealed mutations in not only the spike protein but the whole genome, which may be responsible for the enhanced pathogenicity of SMA1901 in wild-type BALB/c mice. SMA1901 induced age-related mortality similar to that observed in SARS and COVID-19. Drug testing using antibodies and antiviral molecules indicated that this mouse-adapted virus strain can be used to test prophylactic and therapeutic drug candidates against SARSr-CoVs. IMPORTANCE The genetic diversity of SARSr-CoVs in wildlife and their potential risk of cross-species infection highlights the importance of developing a powerful animal model to evaluate the antibodies and antiviral drugs. We acquired the mouse-adapted strain of a bat-origin coronavirus named SMA1901 by natural serial passaging of rRsSHC014S in BALB/c mice. The SMA1901 infection caused interstitial pneumonia and inflammatory immune responses in both young and aged BALB/c mice after intranasal inoculation. Our model exhibited age-related mortality similar to SARS and COVID-19. Therefore, our model will be of high value for investigating the pathogenesis of bat SARSr-CoVs and could serve as a prospective test platform for prophylactic and therapeutic candidates.

[Analysis of influencing factors of secondary metabolites contents in cultivated Polygala tenuifolia].

This work was launched to explore the effect of habitat and growth year on the secondary metabolites contents of cultivated Polygala tenuifolia. The samples of cultivated P. tenuifolia were analyzed by ultra-high performance liquid chromatography(UPLC)-quadrupole time-of-flight mass spectrometry(Q-TOF MS), and the obtained data were analyzed using multiple statistical analysis and cluster analysis. The results showed that compared with growth year, habitat is a main influencing factor which affected the secondary metabolites contents of P. tenuifolia. The contents of sucrose esters and oligosacchride multi-esters are greatly dependent on the habitat (the sample-AG with high levels of components of tenuifoliside B and tenuifoliside C, and the sample-FY with high levels of 3,6'-disinapoyl sucrose, tenuifoliose S, tenuifoliose L, and tenuifoliose V). There is no obvious effect of habitat and growth year on xanthone. The contents of triterpene saponins are greatly dependent on the growth year, and the content of parts of triterpene saponins increased as time goes on.The result indicated that the effect of habitat and growth year on different types of secondary metabolites is not completely equivalent. This study will contribute to the breeding of P. tenuifolia and amendment of current commodity criteria.

[Metabolic products and pathway of neferine in rat liver].

The present study utilized LC-MS and HPLC approaches to characterize the metabolites of neferine in rat liver after an oral administration of 20 mg x kg(-1), and investigated the involvement of CYP450 isoforms in the metabolism of neferine by their selective inhibitors in vitro, separately. In positive ionization mode, besides neferine, four metabolites (M1-M4) were detected. M2 (the major metabolite) and M4 were identified as liensinine and isoliensinine by comparison with reference substances. Moreover, according to the analysis of metabolic rule of parent drug (neferine), M1 and M3 may be desmethylliensinine and desmethyl-isoliensinine, respectively. Furthermore, the metabolism of neferine in rat liver microsomes showed that the percentage inhibition of the major metabolism (liensinine) formation was 80.5% by quinidine (10 micromol x L(-1), selective CYP2D1 inhibitor) and 25.7% by ketoconazole (1 micromol x L(-1), selective CYP3A1 inhibitor). Neferine was mainly metabolized by CYP2D1 or CYP3A1 to liensinine, isoliensinine, desmethyl-liensinine and desmethyl-isoliensinine.

[Determination of stilbene derivative in shengfa powders by HPLC].

OBJECTIVE: To develop a new method for the determination of the idiosyncratic component, 2,3,5,4'-tetrahydroxy-stilbene-2-O-beta-D-glycoside in Shengfa Powders. METHOD: A HPLC method was set up, using Hypersil BDS C18 column (5 microns, 4.6 mm x 150 mm), acetonitrile-water(18:82) as mobile phase, with detection at 320 nm. RESULT: The calibration curve was linear in the range of 0.45-2.25 micrograms, r = 0.9998, the average recovery was 99.5%, RSD = 1.2%(n = 6). CONCLUSION: The active constituent 2,3,5,4'-tetrahydroxy-stilbene-2-O-beta-D-glycoside in Shengfa Powders can be separated effectively. This method is simple, specific and exact.