Influenza A virus (IAV) infection is still a major global threat for humans, especially for the risk groups: young children and the elderly. The currently licensed antiviral drugs target viral factors and are prone to viral resistance. In recent years, a few endogenous small molecules from host, such as estradiol and omega-3 polyunsaturated fatty acid (PUFA)-derived lipid mediator protection D1 (PD1), were demonstrated to be capable of inhibiting IAV infection. Chenodeoxycholic acid (CDCA), one of the main primary bile acids, is synthesized from cholesterol in the liver and classically functions in emulsification and absorption of dietary fats. Clinically, CDCA has been used in the treatment of patients with cholesterol gallstones for more than five decades. In this study, we showed that CDCA attenuated the replication of three subtypes of influenza A virus, including a highly pathogenic H5N1 strain, in A549 and MDCK cell cultures with IC50 ranging from 5.5 to 11.5 μM. Mechanistically, CDCA effectively restrained the nuclear export of viral ribonucleoprotein (vRNP) complexes. In conclusion, as an endogenous physiological small molecule, CDCA can inhibit IAV replication in vitro, at least in part, by blocking vRNP nuclear export, and affords further studies for development as a potential antiviral agent against IAV infections.

Taxonomists are divided over the infrageneric classification and species delimitation within the genus Cycas. The division is largely determined by whether a broad or narrow species concept is adopted, the latter approach being based on apparently minor morphological differences. It is well known that cytokinesis in the cells of pollen provides important evidence for plant taxonomy, particularly at the higher taxonomic level. Here we present the first broad comparison of the cytokinesis of male meiosis in five species of Cycas. A comparative analysis of microsporogenesis in Cycas was carried out using conventional microscopy, semi‐thin sectioning, histochemistry, and fluorescence microscopy with a focus on the cytokinesis of meiosis in the pollen of dividing cells. Our observations confirmed that, contrary to previous reports, the cytokinesis in male meiosis of five species in Cycas is simultaneous at the end of second meiosis. The basic model of microsporogenesis and its systematic implications in Cycas is discussed based both on previous reports and our new results.

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