Evidence for a Structural Role for Acid-Fast Lipids in Oocyst Walls of Cryptosporidium, Toxoplasma, and Eimeria

Coccidia are protozoan parasites that cause significant human disease and are of major agricultural importance. Cryptosporidium spp. cause diarrhea in humans and animals, while Toxoplasma causes disseminated infections in fetuses and untreated AIDS patients. Eimeria is a major pathogen of commercial chickens. Oocysts, which are the infectious form of Cryptosporidium and Eimeria and one of two infectious forms of Toxoplasma (the other is tissue cysts in undercooked meat), have a multilayered wall. Recently we showed that the inner layer of the oocyst walls of Toxoplasma and Eimeria is a porous scaffold of fibers of β-1,3-glucan, which are also present in fungal walls but are absent from Cryptosporidium oocyst walls. Here we present evidence for a structural role for lipids in the oocyst walls of Cryptosporidium, Toxoplasma, and Eimeria. Briefly, oocyst walls of each organism label with acid-fast stains that bind to lipids in the walls of mycobacteria. Polyketide synthases similar to those that make mycobacterial wall lipids are abundant in oocysts of Toxoplasma and Eimeria and are predicted in Cryptosporidium. The outer layer of oocyst wall of Eimeria and the entire oocyst wall of Cryptosporidium are dissolved by organic solvents. Oocyst wall lipids are complex mixtures of triglycerides, some of which contain polyhydroxy fatty acyl chains like those present in plant cutin or elongated fatty acyl chains like mycolic acids. We propose a two-layered model of the oocyst wall (glucan and acid-fast lipids) that resembles the two-layered walls of mycobacteria (peptidoglycan and acid-fast lipids) and plants (cellulose and cutin). IMPORTANCE Oocysts, which are essential for the fecal-oral spread of coccidia, have a wall that is thought responsible for their survival in the environment and for their transit through the stomach and small intestine. While oocyst walls of Toxoplasma and Eimeria are strengthened by a porous scaffold of fibrils of β-1,3-glucan and by proteins cross-linked by dityrosines, both are absent from walls of Cryptosporidium. We show here that all oocyst walls are acid fast, have a rigid bilayer, dissolve in organic solvents, and contain a complex set of triglycerides rich in polyhydroxy and long fatty acyl chains that might be synthesized by an abundant polyketide synthase. These results suggest the possibility that coccidia build a waxy coat of acid-fast lipids in the oocyst wall that makes them resistant to environmental stress.National Institutes of Health (U.S.) (Grant GM31318

Eugenol triggers apoptosis in breast cancer cells through E2F1/survivin down-regulation

Abstract Background Breast cancer is a major health problem that threatens the lives of millions of women worldwide each year. Most of the chemotherapeutic agents that are currently used to treat this complex disease are highly toxic with long-term side effects. Therefore, novel generation of anti-cancer drugs with higher efficiency and specificity are urgently needed. Methods Breast cancer cell lines were treated with eugenol and cytotoxicity was measured using the WST-1 reagent, while propidium iodide/annexinV associated with flow cytometry was utilized in order to determine the induced cell death pathway. The effect of eugenol on apoptotic and pro-carcinogenic proteins, both in vitro and in tumor xenografts was assessed by immunoblotting. While RT-PCR was used to determine eugenol effect on the E2F1 and survivin mRNA levels. In addition, we tested the effect of eugenol on cell proliferation using the real-time cell electronic sensing system. Results Eugenol at low dose (2 μM) has specific toxicity against different breast cancer cells. This killing effect was mediated mainly through inducing the internal apoptotic pathway and strong down-regulation of E2F1 and its downstream antiapoptosis target survivin, independently of the status of p53 and ERα. Eugenol inhibited also several other breast cancer related oncogenes, such as NF-κB and cyclin D1. Moreover, eugenol up-regulated the versatile cyclin-dependent kinase inhibitor p21WAF1 protein, and inhibited the proliferation of breast cancer cells in a p53-independent manner. Importantly, these anti-proliferative and pro-apoptotic effects were also observed in vivo in xenografted human breast tumors. Conclusion Eugenol exhibits anti-breast cancer properties both in vitro and in vivo, indicating that it could be used to consolidate the adjuvant treatment of breast cancer through targeting the E2F1/survivin pathway, especially for the less responsive triple-negative subtype of the disease. </jats:sec

A simple and rapid lysis method for preparation of genomic DNA from Gram-negative bacteria

A very efficient, simple and economic lysis method for rapid preparation of genomic DNA from Gramnegative bacteria was developed. This method includes a novel step lysis by treatment with carvacrol followed by simple ethanol precipitation. The procedure was realised without using of detergents or enzymes. Moreover, the resultant genomic DNA was in good quantity and quality and can be used successfully for restriction endonucleases digestion, PCR amplification and others types of molecular biology manipulations.Keywords: Genomic DNA, lysis, carvacrol, Gram-negative bacteria, Escherichia coli, Erwinia chrysanthem

Accompagnement entrepreneurial au sein de l’université : vers une pédagogie innovante

La conception et l’application de méthodes pédagogiques innovantes dans l’enseignement et dans l’accompagnement à l’entrepreneuriat au sein de l’université font partie des pistes intéressantes pour développer la relation Université-Entrepreneuriat. L’objectif de cet article est de proposer une nouvelle approche d’enseignement et d’accompagnement à l’entrepreneuriat basée sur un nouveau paradigme en émergence, c’est le paradigme de l’agir entrepreneurial (Schmitt, 2015). De ce fait, nous allons procéder en deux temps. Tout d’abord, nous mettrons en évidence le modèle conceptuel permettant de se libérer de l’approche traditionnelle d’enseignement de l’entrepreneuriat centrée sur la création d’entreprise, pour s’inscrire dans une nouvelle approche centrée sur le processus d’apprentissage lié au processus entrepreneurial. Ensuite, à partir de ce modèle conceptuel, nous aborderons les repères méthodologiques pour opérationnaliser le paradigme de l’agir entrepreneurial dans l’accompagnement entrepreneurial au sein de l’université. Dans cette perspective nous allons nous intéresser à deux éléments essentiels, la posture de l’enseignant et la mobilisation de nouveaux outils d’accompagnement entrepreneurial

Comparative study of the antifungal activity of some essential oils and their major phenolic components against Aspergillus niger using three different methods

This study aimed to evaluate the antimould activity of oregano, thyme, rosemary and clove essential oils and some of their main constituents: eugenol, carvacrol and thymol against Aspergillus niger. This antifungal activity was assessed using broth dilution, disc diffusion and micro atmosphere methods. In both agar diffusion and micro atmosphere tests, all the investigated agents showed no inhibitory effect on Aspergillus niger growth at concentrations lower than 10% (v/v). However, broth dilution test showed the highest sensitivity. Using this method, the minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) values of the tested agents were between 0.025 and 1%. The anti-Aspergillus effect of oregano and thyme oils was more potent than that of clove and rosemary oils. Concerning the phenolic compounds, thymol and carvacrol proved to have better anti-Aspergillus effect than eugenol. Accordingly, we can say that the antifungal efficacy of these agents is better appreciated when they are applied directly into liquid medium than when they are applied as volatiles or diffused in solid medium. Therefore, as these agents are active at low concentrations, they could be used in the formulation of natural preparations, and thereby could be proposed in therapeutic or hygienic contexts.Key words: Essential oils, thymol, carvacrol, antifungal activity, Aspergillus niger, micro atmosphere, agar diffusion, broth dilution

Lithological and Geotechnical Characterization of Casablanca’s Urban Subsoil, Morocco

Morocco’s largest city, Casablanca, is expanding rapidly, but geotechnical characteristics related to the region’s subsoil are rarely taken into consideration during construction/building projects. Using field studies, along with a significant database established from civil-engineering work, this study focuses on the lithological and mechanical characterization/behavior of Casablanca’s subsoil in order to gain a clearer interpretation of Casablanca’s (sub)soil. Lithology maps and cross-sections show the variation of Quaternary cover thickness, which is controlled by the shape of the synclines and anticlines in the folded Paleozoic bedrock. The texture of surface soils was described by percentage of gravel, sand, silt, tuff, and clay, resulting in a low to medium plastic nature, with a plasticity index (PI) between 8% and 25%. Owing to the silty nature of soils, they will likely shrink and swell against any foundation, weakening it over time. This study’s analyses facilitate decision-making related to pre-construction locational choices through its identification of suitable areas for building or, if building in a less stable area, recognizing that some type of earthwork improvement should be constructed before any foundation is created. Otherwise, any construction in the Casablanca area will be at risk for foundational damages