Antibiotic resistance is a major concern in Clostridium difficile, the causative agent of antibiotic-associated diarrhea. Reduced susceptibility to first- and second-line agents is widespread, therefore various attempts have been made to seek alternative preventive and therapeutic strategies against this pathogen. In this work, the antimicrobial properties of asiatic acid were evaluated against C. difficile. Asiatic acid displayed substantial inhibitory effects on 19 C. difficile isolates collected from different sources with minimal inhibitory concentrations ranging from 10 to 20 μg/ml. Time kill analysis and minimal bactericidal concentration revealed potential bactericidal activity of this compound. Asiatic acid induced membrane damages and alterations in morphological ultrastructure in C. difficile, thereby causing the leakage of intracellular substances. Moreover, asiatic acid also displayed an inhibitory effect on cell motility, but did not interfere with biofilm formation and spore germination. Analysis of drug combination showed no synergistic effect between asiatic acid and vancomycin/metronidazole. Altogether, asiatic acid exhibited strong antimicrobial activity against vegetative cells and could serve as an alternative resource for tackling C. difficile.

Despite the recent introduction of a commercial vaccine, the mosquito-transmitted dengue virus is still a worldwide public health problem. Based on the live attenuated vaccine strategy, the commercial vaccine has a less than optimal protective profile. Virus-like particles (VLPs) offer an attractive alternate vaccination strategy due to the effectively native presentation of epitopes in the absence of any infectious genetic material. However, the production of amounts of VLP in a platform that can support commercial development remains a major obstacle. This study generated two DENV 2 VLPs [codon-optimized and chimeric DENV/Japanese encephalitis virus (JEV)] and directly compared yields of these constructs by western blotting and dot blot hybridization. The effect of oleic acid supplementation, a process known to increase DENV production in natural infection, was also investigated. Results showed that the chimeric construct gave a two- to threefold higher yield than the codon-optimized construct and that while oleic acid increased DENV virion production in natural infection, it inhibited VLP production. These results suggest that further optimization of DENV VLP expression is possible, but it will require more understanding of how native DENV infection remodels the host cell machinery.

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Organizing a zoology laboratory for an undergraduate course is often a challenge, particularly in a limited-resource setting, due to the vast variety of topics to cover and the limited numbers of preserved specimens and permanent slides. In zoology, the class structure generally takes the form of a lecture demonstration followed by sample exhibition stations. This setting often fails to actively engage the majority of students in exploring the specimens. Here we propose an alternative organization of a zoology class lab format comprised of short guided-inquiry, time-restricted lab stations, and a freely structured follow-up project intended to increase attention and conceptual understanding of the lab topic. The lab is designed in two parts: a 10-minute in-class rotation portion, where small groups of students take turns investigating specimens following an instructor demonstration, and an after-class group assignment. We implemented the strategy for two years, and it is clear that our approach significantly increased students’ active engagement in the class. The time-restricted scheme ensures all students participate despite limited resources, while the guided instructions keep the students focused on the topic. Furthermore, the team assignment portion, in particular the media creation aspect, promoted teamwork among group members.