Buruli ulcer, caused by Mycobacterium ulcerans infections, is a necrotizing skin disease whose pathogenesis is associated with the exotoxin mycolactone. Despite the relevance of this emergent disease, little is known on the immune response against the pathogen. Following the recent demonstration of an intramacrophage growth phase for M. ulcerans, we investigated the biological relevance of IFN-γ and the antimycobacterial mechanisms activated by this cytokine in M. ulcerans-infected macrophages. Three M. ulcerans strains were tested: 5114 (mutant mycolactone-negative, avirulent strain); 94–1327 (intermediate virulence); and 98–912 (high virulence). We show in this study that IFN-γ is expressed in mouse-infected tissues and that IFN-γ–deficient mice display increased susceptibility to infection with strains 5114 and, to a lesser extent, 94–1327, but not with the highly virulent strain. Accordingly, IFN-γ–activated cultured macrophages controlled the proliferation of the avirulent and the intermediate virulent strains. Addition of mycolactone purified from strain 98–912 to cultures of IFN-γ–activated macrophages infected with the mycolactone-negative strain led to a dose-dependent inhibition of the IFN-γ–induced protective mechanisms, involving phagosome maturation/acidification and increased NO production, therefore resulting in increased bacterial burdens. Our findings suggest that the protection mediated by IFN-γ in M. ulcerans-infected macrophages is impaired by the local buildup of mycolactone.

Project-Based Learning (PBL) has been implemented in the first year of the Industrial Engineering and Management programme at the University of Minho, Portugal, since 2004/2005. The purpose of this paper is to analyse and discuss teachers' experiences in PBL in this programme and to explore its implications for student learning and for teaching practices in higher education. For data collection, the research method used was written narratives to these teachers, at the end of the PBL semester. Findings suggest that teachers express a positive view of PBL as a learning approach. They identify student motivation and engagement, along with a better understanding of the application of concepts in real-life situations, as important outcomes of the project for students. Besides this, teachers also highlight the importance of the development of transversal skills by students throughout the project. Recommendations for future work and implications for practice will also be discussed.

Buruli ulcer (BU) is a neglected tropical disease caused by Mycobacterium ulcerans. The tissue damage characteristic of BU lesions is known to be driven by the secretion of the potent lipidic exotoxin mycolactone. However, the molecular action of mycolactone on host cell biology mediating cytopathogenesis is not fully understood. Here we applied two-dimensional electrophoresis (2-DE) to identify the mechanisms of mycolactone's cellular action in the L929 mouse fibroblast proteome. This revealed 20 changed spots corresponding to 18 proteins which were clustered mainly into cytoskeleton-related proteins (Dync1i2, Cfl1, Crmp2, Actg1, Stmn1) and collagen biosynthesis enzymes (Plod1, Plod3, P4ha1). In line with cytoskeleton conformational disarrangements that are observed by immunofluorescence, we found several regulators and constituents of both actin- and tubulin-cytoskeleton affected upon exposure to the toxin, providing a novel molecular basis for the effect of mycolactone. Consistent with these cytoskeleton-related alterations, accumulation of autophagosomes as well as an increased protein ubiquitination were observed in mycolactone-treated cells. In vivo analyses in a BU mouse model revealed mycolactone-dependent structural changes in collagen upon infection with M. ulcerans, associated with the reduction of dermal collagen content, which is in line with our proteomic finding of mycolactone-induced down-regulation of several collagen biosynthesis enzymes. Our results unveil the mechanisms of mycolactone-induced molecular cytopathogenesis on exposed host cells, with the toxin compromising cell structure and homeostasis by inducing cytoskeleton alterations, as well as disrupting tissue structure, by impairing the extracellular matrix biosynthesis. Buruli Ulcer (BU) is a neglected tropical disease caused by Mycobacterium ulcerans infection. It has been recognized for many years that BU pathogenesis is mediated by the potent exotoxin mycolactone; however, the molecular action of this toxin on the host cell biology that drives its pathogenesis is not fully understood. Here we present a proteomic-based study that explores the molecular action of mycolactone on host cells biology. Our results provide further molecular evidence for the cytoskeleton-disarrangement induced by mycolactone, and unveil its impact on cytoskeleton-dependent cellular functions. Moreover, we extend the field of action of this toxin to the biosynthesis of collagen, implicating mycolactone on the decrease of dermal collagen found on BU lesions. Given the dependence of M. ulcerans virulence on its toxin, these findings on mycolactone's molecular action on host cells and tissues are of major importance for the understanding of BU pathogenesis.

Cancer is one of the leading causes of death worldwide. In the available treatments, chemotherapy is one of the most used, but has several associated problems, namely the high toxicity to normal cells and the resistance acquired by cancer cells to the therapeutic agents. The scientific community has been battling against this disease, developing new strategies and new potential chemotherapeutic agents. However, new drugs often exhibit poor solubility in water, which led researchers to develop functionalized nanosystems to carry and, specifically deliver, the drugs to cancer cells, targeting overexpressed receptors, proteins, and organelles. Thus, this review is focused on the recent developments of functionalized nanosystems used to carry poorly water-soluble drugs, with special emphasis on liposomes and albumin-based nanosystems, two major classes of organic nanocarriers with formulations already approved by the U.S. Food and Drug Administration (FDA) for cancer therapeutics.