Active teaching methodologies have been placed as a hope for changing education at different levels, transiting from passive lecture‐centered to student‐centered learning. With the health measures of social distance, the COVID‐19 pandemic forced a strong shift to remote education. With the challenge of delivering quality education through a computer screen, we validated and applied an online course model using active teaching tools for higher education. We incorporated published active‐learning strategies into an online construct, with problem‐based inquiry and design of inquiry research projects to serve as our core active learning tool. The gains related to students' science learning experiences and their attitudes toward science were assessed by applying questionnaires before, during, and after the course. The course counted on the participation of 83 students, most of them (60.8%) from postgraduate students. Our results show that engagement provided by active learning methods can improve performance both in hard and soft skills. Students' participation seems to be more relevant when activities require the interaction of information, prediction, and reasoning, such as open‐ended questions and design of research projects. Therefore, our data show that, in pandemic, active learning tools benefit students and improve their critical thinking and their motivation and positive positioning in science.

Extracellular vesicles (EVs) are released by a wide number of cells including blood cells, immune system cells, tumour cells, adult and embryonic stem cells. EVs are a heterogeneous group of vesicles (~30–1000 nm) including microvesicles and exosomes. The physiological release of EVs represents a normal state of the cell, raising a metabolic equilibrium between catabolic and anabolic processes. Moreover, when the cells are submitted to stress with different inducers or in pathological situations (malignancies, chronic diseases, infectious diseases.), they respond with an intense and dynamic release of EVs. The EVs released from stimulated cellsvsthose that are released constitutively may themselves differ, both physically and in their cargo. EVs contain protein, lipids, nucleic acids and biomolecules that can alter cell phenotypes or modulate neighbouring cells. In this review, we have summarized findings involving EVs in certain protozoan diseases. We have commented on strategies to study the communicative roles of EVs during host–pathogen interaction and hypothesized on the use of EVs for diagnostic, preventative and therapeutic purposes in infectious diseases. This kind of communication could modulate the innate immune system and reformulate concepts in parasitism. Moreover, the information provided within EVs could produce alternatives in translational medicine.

Giardia intestinalis is a flagellated unicellular protozoan that colonizes the small intestine, causing the diarrheal disease called giardiasis. The production of extracellular vesicles (EVs) by G. intestinalis and the role of these EVs in the parasite’s interaction with the host have been described. According to biogenesis, EVs are grouped mainly into large (microvesicles—derived from the plasma membrane) and small (exosomes—derived from multivesicular bodies). Populations of EVs are heterogeneous, and improved methods to separate and study them are needed to understand their roles in cell physiology and pathologies. This work aimed to enrich the large extracellular vesicles (LEVs) of G. intestinalis in order to better understand the roles of these vesicles in the interaction of the parasite with the host. To achieve the enrichment of the LEVs, we have modified our previously described method and compared it by protein dosage and using Nano tracking analysis. Giardia intestinalis vesiculation was induced by incubation in a TYI-S-33 medium without serum, to which 1 mM of CaCl₂ was added at 37 °C for 1 h. Then, the supernatant was centrifuged at 15,000× g for 1 h (15 K 1 h pellet), 15,000× g for 4 h (15 K 4 h pellet) and 100,000× g for 1.5 h (100 K 1h30 pellet). The pellet (containing EVs) was resuspended in 1× PBS and stored at 4 °C for later analysis. The EVs were quantified based on their protein concentrations using the Pierce BCA assay, and by nanoparticle tracking analysis (NTA), which reports the concentration and size distribution of the particles. The NTA showed that direct ultracentrifugation at 100,000× g for 1.5 h and centrifugation at 15,000× g for 4 h concentrated more EVs compared to centrifugation at 15,000× g for 1 h. Additionally, it revealed that centrifugation at 15,000× g 4 h was able to concentrate at the same particle concentration levels as a direct ultracentrifugation at 100,000× g for 1.5 h. As for the enrichment of LEVs, the NTA has shown a higher concentration of LEVs in direct ultracentrifugation at 100,000× g for 1.5 h, and in centrifugation at 15,000× g for 4 h, compared to centrifugation at 15,000× g for 1 h. Our results have shown that the most used method at 15,000× g for 1 h is not enough to obtain a representative population of large EVs, and we suggest that LEVs released by G. intestinalis can be better enriched by direct ultracentrifugation at 100,000× g for 1.5 h, or by centrifugation at 15,000× g for 4 h.