ObjectiveSince December 2019, a newly identified coronavirus (severe acute respiratory syndrome coronavirus (SARS-CoV-2)) has caused outbreaks of pneumonia in Wuhan, China. SARS-CoV-2 enters host cells via cell receptor ACE II (ACE2) and the transmembrane serine protease 2 (TMPRSS2). In order to identify possible prime target cells of SARS-CoV-2 by comprehensive dissection of ACE2 and TMPRSS2 coexpression pattern in different cell types, five datasets with single-cell transcriptomes of lung, oesophagus, gastric mucosa, ileum and colon were analysed.DesignFive datasets were searched, separately integrated and analysed. Violin plot was used to show the distribution of differentially expressed genes for different clusters. The ACE2-expressing and TMPRRSS2-expressing cells were highlighted and dissected to characterise the composition and proportion.ResultsCell types in each dataset were identified by known markers. ACE2 and TMPRSS2 were not only coexpressed in lung AT2 cells and oesophageal upper epithelial and gland cells but also highly expressed in absorptive enterocytes from the ileum and colon. Additionally, among all the coexpressing cells in the normal digestive system and lung, the expression of ACE2 was relatively highly expressed in the ileum and colon.ConclusionThis study provides the evidence of the potential route of SARS-CoV-2 in the digestive system along with the respiratory tract based on single-cell transcriptomic analysis. This finding may have a significant impact on health policy setting regarding the prevention of SARS-CoV-2 infection. Our study also demonstrates a novel method to identify the prime cell types of a virus by the coexpression pattern analysis of single-cell sequencing data.

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A 10-mer overlapping peptide library has been synthesized for screening and identification of linear B-cell epitopes of severe acute respiratory syndrome associated coronavirus (SARS-CoV), which spanned the major structural proteins of SARS-CoV. One hundred and eleven candidate peptides were positive according to the result of PEPscan, which were assembled into 22 longer peptides. Five of these peptides showed high cross-immunoreactivities (approximately 66.7 to 90.5%) to SARS convalescent patients' sera from the severest epidemic regions of the China mainland. Most interestingly, S(471-503), a peptide located at the receptor binding domain (RBD) of SARS-CoV, could specifically block the binding between the RBD and angiotensin-converting enzyme 2, resulting in the inhibition of SARS-CoV entrance into host cells in vitro. The study demonstrated that S(471-503) peptide was a potential immunoantigen for the development of peptide-based vaccine or a candidate for further drug evaluation against the SARS-CoV virus-cell fusion.

The coronavirus disease 2019 (COVID‐19) pandemic has become a serious burden on global public health. Although therapeutic drugs against COVID‐19 have been used in many countries, their efficacy is still limited. We here reported nanobody (Nb) phage display libraries derived from four camels immunized with the SARS‐CoV‐2 spike receptor‐binding domain (RBD), from which 381 Nbs were identified to recognize SARS‐CoV‐2‐RBD. Furthermore, seven Nbs were shown to block interaction of human angiotensin‐converting enzyme 2 (ACE2) with SARS‐CoV‐2‐RBD variants and two Nbs blocked the interaction of human ACE2 with bat‐SL‐CoV‐WIV1‐RBD and SARS‐CoV‐1‐RBD. Among these candidates, Nb11‐59 exhibited the highest activity against authentic SARS‐CoV‐2 with 50% neutralizing dose (ND50) of 0.55 μg/ml. Nb11‐59 can be produced on large scale in Pichia pastoris, with 20 g/L titer and 99.36% purity. It also showed good stability profile, and nebulization did not impact its stability. Overall, Nb11‐59 might be a promising prophylactic and therapeutic molecule against COVID‐19, especially through inhalation delivery.

UL16-binding proteins (ULBPs 14 -21). ULBP gene family consists of 10 members, six of which encode potentially functional glycoproteins that are located near the tip of its long arm at q24.2-q25.3, close to the human equivalent of the mouse H2-linked t-complex. This subchromosomal region is similar to a segment of mouse chromosome 10 harboring the orthologous MHC class I-related retinoic acid early transcript loci, Raet1a-d (22). Among them, ULBP1, ULBP2, ULBP3, and RAET1L are linked to membrane through a glycosylphosphatidylinositol anchor, whereas RAET1E and RAET1G contain transmembrane and cytoplasmic domains.By engaging the NKG2D activating receptor, ULBPs can directly activate NK cells to proliferate and secrete cytokines. Co-stimulation of NK cells with ULBPs and interleukin-12 greatly enhances the production of multiple cytokines and chemokines (17). In addition, in vitro, some target cells insensitive to NK cells can be efficiently lysed when transfected with ULBPs (14,19,21). In vivo, the expression of ULBPs correlates with improved survival in cancer patients, and ectopic expression of ULBPs on murine EL4 or RMA tumor cells elicits potent anti-tumor responses in syngeneic C57BL/6 and severe combined immunodeficiency disease mice, which can be strongly enhanced by interleukin-15 (20). Accordingly, Andreas Diefenbach et al. (23) demonstrated the efficacy of using NKG2D ligands as components of vaccine, which may offer new approaches for malignancies. Moreover, it was shown that DNA-based vaccines encoding syngeneic or allogeneic NKG2D ligands together with tumor antigens could markedly activate both innate and adaptive anti-tumor immunity (24,25

Ginsenosides are the major bioactive constituents of Panax ginseng, which have pharmacological effects. Although there are several reviews in regards to ginsenosides, new ginsenosides have been detected continually in recent years. This review updates the ginsenoside list from P. ginseng to 170 by the end of 2019, and aims to highlight the diversity of ginsenosides in multiple dimensions, including chemical structure, tissue spatial distribution, time, and isomeride. Protopanaxadiol, protopanaxatriol and C17 side-chain varied (C17SCV) manners are the major types of ginsenosides, and the constitute of ginsenosides varied significantly among different parts. Only 16 ginsenosides commonly exist in all parts of a ginseng plant. Protopanaxadiol-type ginsenoside is dominant in root, rhizome, leaf, stem, and fruit, whereas malonyl- and C17SCV-type ginsenosides occupy a greater proportion in the flower and flower bud compared with other parts. In respects of isomeride, there are 69 molecular formulas corresponding to 170 ginsenosides, and the median of isomers is 2. This is the first review on diversity of ginsenosides, providing information for reasonable utilization of whole ginseng plant, and the perspective on studying the physiological functions of ginsenoside for the ginseng plant itself is also proposed.

Probiotics have been used to rebuild the antibiotic-induced dysfunction in gut microbiota, but whether the different strains of probiotics result in similar or reverse effects remains unclear. In this study, the different recovery effects of two cocktails (each contains four strains) of Lactobacillus and fructooligosaccharide against cefixime-induced change of gut microbiota were evaluated in C57BL/6J mice. The results show that the use of cefixime caused a reduction in the diversities of the microbial community and led to significantly decreasing to one preponderant Firmicutes phylum, which was difficult to restore naturally in the short term. The gut microbiota compositions of the groups treated with the probiotic cocktails were much more diverse than those of the natural recovery group. The effects of Lactobacillus cocktails against the cefixime-induced gut microbiota change may mainly be due to the beneficial SCFAs production in vivo and also be related to the good cell adhesion properties performed in vitro. Meanwhile, the restoration of the cefixime-induced gut microbiota was significantly different between two Lactobacillus groups since the Lactobacillus strains with high levels of fructooligosaccharide use and better cell adhesion properties performed considerably better than the Lactobacillus strains with high survival rates in the gastrointestinal tract. The contents of short-chain fatty acids in ceca were increased to 26.483±1.925 and 25.609±2.782μmol/g in the two probiotic cocktail groups respectively compared to 15.791±0.833μmol/g (P<0.05) in control group. Moreover, intestinal inflammation was alleviated by administration of the Lactobacillus cocktails. However, fructooligasaccharide administration showed certain effects on gut microbiota restoration (such as an increase of Akkermansia), although its effect on the entire microbiome structure is not so obvious.

Ginseng is a traditional medicinal herb commonly consumed world-wide owing to its unique family of saponins called ginsenosides. The absorption and bioavailability of ginsenosides mainly depend on an individual’s gastrointestinal bioconversion abilities. There is a need to improve ginseng processing to predictably increase the pharmacologically active of ginsenosides. Various types of ginseng, such as fresh, white, steamed, acid-processed, and fermented ginsengs, are available. The various ginseng processing methods produce a range ginsenoside compositions with diverse pharmacological properties. This review is intended to summarize the properties of the ginsenosides found in different Panax species as well as the different processing methods. The sugar moiety attached to the C–3, C–6, or C–20 deglycosylated to produce minor ginsenosides, such as Rb1, Rb2, Rc, Rd→Rg3, F2, Rh2; Re, Rf→Rg1, Rg2, F1, Rh1. The malonyl-Rb1, Rb2, Rc, and Rd were demalonylated into ginsenoside Rb1, Rb2, Rc, and Rd by dehydration. Dehydration also produces minor ginsenosides such as Rg3→Rk1, Rg5, Rz1; Rh2→Rk2, Rh3; Rh1→Rh4, Rk3; Rg2→Rg6, F4; Rs3→Rs4, Rs5; Rf→Rg9, Rg10. Acetylation of several ginsenosides may generate acetylated ginsenosides Rg5, Rk1, Rh4, Rk3, Rs4, Rs5, Rs6, and Rs7. Acid processing methods produces Rh1→Rk3, Rh4; Rh2→Rk1, Rg5; Rg3→Rk2, Rh3; Re, Rf, Rg2→F1, Rh1, Rf2, Rf3, Rg6, F4, Rg9. Alkaline produces Rh16, Rh3, Rh1, F4, Rk1, ginsenoslaloside-I, 20(S)-ginsenoside-Rh1-60-acetate, 20(R)-ginsenoside Rh19, zingibroside-R1 through hydrolysis, hydration addition reactions, and dehydration. Moreover, biological processing of ginseng generates the minor ginsenosides of Rg3, F2, Rh2, CK, Rh1, Mc, compound O, compound Y through hydrolysis reactions, and synthetic ginsenosides Rd12 and Ia are produced through glycosylation. This review with respect to the properties of particular ginsenosides could serve to increase the utilization of ginseng in agricultural products, food, dietary supplements, health supplements, and medicines, and may also spur future development of novel highly functional ginseng products through a combination of various processing methods.