Trypanosoma cruzi, which causes Chagas disease, is a significant health threat in many countries and affects millions of people. Given the magnitude of this disease, a broader understanding of trypanocidal mechanisms is needed to prevent and treat infection. Natural endoperoxides, such as ergosterol peroxide, have been shown to be toxic to parasites without causing harm to human cells or tissues. Although prior studies have demonstrated the trypanocidal activity of ergosterol peroxide, the cellular and molecular mechanisms remain unknown. The results of this study indicate that a free-radical reaction occurs in T. cruzi following ergosterol peroxide exposure, leading to cell death. Using a combination of biochemical, microscopic and in silico experimental approaches, we have identified, for the first time, the cellular and molecular cytotoxic mechanism of an ergosterol peroxide obtained from Pleurotus ostreatus (Jacq) P. Kumm. f. sp. Florida.

Dysentery is an inflammation of the intestine caused by the protozoan parasite Entamoeba histolytica and is a recurrent health problem affecting millions of people worldwide. Because of the magnitude of this disease, finding novel strategies for treatment that does not affect human cells is necessary. Ergosterol peroxide is a sterol particularly known as a major cytotoxic agent with a wide spectrum of biological activities produced by edible and medicinal mushrooms. The aim of this report is to evaluate the amoebicidal activity of ergosterol peroxide (5α, 8α-epidioxy-22E-ergosta-6,22-dien-3β-ol isolated from 5α, 8α-epidioxy-22E-ergosta-6,22-dien-3β-ol) (Jacq.) P. Kumm. f. sp. Florida. Our results show that ergosterol peroxide produced a strong cytotoxic effect against amoebic growth. The inhibitory concentration IC50 of ergosterol peroxide was evaluated. The interaction between E. histolytica and ergosterol peroxide in vitro resulted in strong amoebicidal activity (IC50  = 4.23 nM) that may be due to the oxidatory effect on the parasitic membrane. We also tested selective toxicity of ergosterol peroxide using a cell line CCL-241, a human epithelial cell line isolated from normal human fetal intestinal tissue. To the best of our knowledge, this is the first report on the cytotoxicity of ergosterol peroxide against E. histolytica, which uncovers a new biological property of the lipidic compound isolated from Pleurotus ostreatus (Jacq.) P. Kumm. f. sp. Florida.

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Various species of the genus Ganoderma have been used for centuries according to oriental tradition as a source of medicines and nutrients. A chemical study of the fruiting bodies and mycelial culture of G. oerstedii was carried out with the idea of isolating and characterizing active natural components present to make use of their potential pharmaceutical application in Mexico. The fruiting bodies and mycelial culture of G. oesrtedii were lyophylized and extracted one after the other with hexane, chloroform, and methanol. Following this process, each substance was extracted separately by using column chromatography. From fruiting bodies eight metabolites, five sterols (ergosta-7,22-dien-3β-ol, ergosterol peroxide, ergosterol, cerevisterol, and ergosta-7,22-dien-3-one) as well as three terpene compounds (ganodermanondiol, ganoderic acid Sz, and ganoderitriol M) were obtained from fruiting bodies. From the mycelial culture three metabolites, two sterols (ergosterol and cerevisterol), and a new terpene compound (ganoderic acetate from the acid) were obtained. These structures were established based on a spectroscopic analysis mainly using nuclear magnetic resonance and a comparison with data already established.

The metabolism of vitamin D is a very important pathway involved in the regulation of sterols and maintenance of cell health. The physiological activity of the human hormone 1α,25-dihydroxyvitamin D3, or calcitriol, is mediated by the vitamin D receptor (VDR), an endocrine member of the nuclear receptor superfamily that inhibits cell growth and stimulates cell differentiation, suggesting a potential application in cancer chemoprevention. Since nonpolar extracts obtained from Ganoderma mushrooms have also been shown to exert an antiproliferative effect on several cancer cell lines, it was suggested that at least part of its activity might be mediated by VDR. The aim of this work was to identify possible VDR ligands from an extensive library of lanostanoids isolated from several Ganoderma mushrooms. Using an in silico approach, 30 lanostanoids were found to interact with the VDR ligand-binding pocket in the same way as calcitriol. The possible implications of using these compounds are discussed here.

Compounds showing pharmacological activity on the immune system are of interest because of their therapeutic potential in the treatment of many diseases. However, data from primary human immune cells and in vivo studies are limited. The aim of this study was to analyze the ability to induce the expression of Toll-like receptors (TLRs) and proinflammatory molecules on cells involved in the immune system using the compound ergosta-7,22-dien-3- one, isolated from a wild Mexican strain of Ganoderma oerstedii. According to our study, ergosta-7,22-dien-3-one did not present any cytotoxic effect on HeLa or J774A.1 cells, and it was able to stimulate nitric oxide production, induce the expression of genes, and induce the production of TLRs, cytokines, chemokines, and cellular adhesion molecules in J774A.1 cells, based on reverse-transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay. Here we report a new pro-inflammatory property of ergosta-7,22-dien-3-one, which should be considered as a possible adjuvant property in view of its biological activity.

El presente artículo muestra resultados de una revisión sistemática de literatura en torno a estrategias didácticas y experiencias de experimentación utilizadas en la enseñanza de las ciencias para analizar el aporte sobre la utilización de conceptos científicos modernos, el desarrollo de habilidades propias de la ciencia y la tecnología y la integración y solución de problemas y prácticas de laboratorio que faciliten el diálogo y la exposición de ideas propias, además de obtener información sobre las características deseables que deberían considerar las herramientas o dispositivos tecnológicos aplicados a la educación que favorezcan el desarrollo de habilidades científicas en los estudiantes. La conformación del corpus de estudio se realizó utilizando operadores booleanos lógicos en las bases de datos Scopus y Dialnet. Los criterios de agrupación-análisis fueron estrategias didácticas y laboratorio escolar o experiencias de experimentación. Los resultados muestran que las estrategias didácticas utilizadas sí abonan al desarrollo de habilidades científicas y conceptos básicos en ciencias. Las actividades de experimentación escolar basadas o no en tecnología como laboratorios virtuales, remotos o electrónicos facilitan la experiencia de indagación científica en la escuela teniendo como área de oportunidad incluir la solución de problemas.

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