Cellular Uptake and Metabolism of Soluplus-based Scopoletin Micelles in Caco-2 Cells / 中国药学杂志

OBJECTIVE: To develop an analytical method for the quantification of scopoletin (Sco) and investigate the cellular uptake and metabolism of polyvinylcaprolactam-polyvinyl acetate-polyethylene glycol (soluplus)-based Sco micelles (Sco-Ms) in Caco-2 cells, as well as exploring the possible mechanisms involved in the oral absorption of Sco-Ms.METHODS: Combined with enzymatic hydrolysis for pretreatment, a liquid chromatography-electrospray ionization-tandem mass spectrometric (LC-MS/MS) method was developed for the quantification of Sco and its corresponding metabolite. Then, cellular uptake efficiency and metabolic rate of Sco were calculated.RESULTS: This method was proven to be linear over the concentration range of 5-1 000 ng•mL-1. Cellular uptake of Sco-Ms increased significantly compared with that of free Sco at various time points. Meanwhile, Sco-Ms inhibited the enzymatic degradation of Sco. Sco-Ms were primarily internalized into enterocytes via macropinocytosis and clathrin-dependent pathways.CONCLUSION: Enhanced cellular uptake and decreased metabolic rate are pivotal mechanisms by which Sco-Ms promotes oral absorption of Sco.

Two Cases of Multi-antibiotic Resistant Cronobacter spp. Infections of Infants in China / 生物医学与环境科学（英文）

Infections by Cronobacter spp. are hazardous to infants since they can lead to neonatal meningitis, bacteremia, and necrotizing enterocolitis. Cronobacter spp. are frequently resistant to β-lactam derivatives, macrolides, and aminoglycosides. In addition, multi-resistant strains have also been detected. In China, the isolation rate of Cronobacter spp. from commercial powdered infant formula (PIF) or follow-up formula (FUF) is relatively high. Nevertheless, clinical cases of Cronobacter infection have been ignored to date. Here we describe two cases of Cronobacter infection detected at the Wuhan Women and Children Medical Care Center Hospital (Wuhan City, China). We provide the genomic analysis of the isolates and the antibiotic-resistance profiles of the two strains. The Cronobacter strains identified in this study were not susceptible to third-generation cephalosporins, aminoglycoside, and/or trimethoprim-sulfamethoxazole. Whole genome sequencing revealed various genes known to encode antibiotic resistance. Future studies are needed to determine whether the genes predicted in this study are functional. As with Enterobacter spp., the antibiotic resistance of Cronobacter is a serious issue that requires more attention.

The Functional Motif of SARS-CoV S Protein Involved in the Interaction with ACE2 / 中国病毒学

SARS-CoV is a newly discovery pathogen causing severe acute respiratory problems.It has been established that the S protein in this pathogen plays an important rule in the adsorption and penetration of SARS-CoV into the host cell by interaction with the ACE2 receptor.To determinant which functional motif of the S protein was involved in the interaction with ACE2,seven truncated S proteins deleted from the N or C terminal were obtained by an E.coli expression system and purified by column chromatography to homogeneity.Each truncated S protein was fixed on to the well of an ELISA plate and an interaction was initiated with the ACE2 protein.The adsorption were quantified by ELISA,and the results indicated that amino acids from 388 to 496 of the S protein was responsible for the interaction with the ACE2 receptor,and the interaction could be completely disrupted by an antibody specific to these amino acids.Deletions adjacent to this domain did not appear to have a significant impact on the interaction with ACE2,suggesting that the S protein of SARS-CoV could be developed as a vaccine to prevent the spread of SARS-CoV.