ABSTRACT The objective of this work was to explore whether the formation of protein nanoparticles, reported in a previous study, occurs in a fraction of an aqueous extract of wheat bran with a particular composition. Using a bottom-up strategy, an aqueous extract of wheat bran was first fractionated by size exclusion chromatography. Each of the chromatographic fractions was hydrolyzed with V8 protease in a reaction medium containing Ca2+. The chromatographic fractions and their hydrolysates were subjected to chemical characterization, electrophoresis, UV-Vis spectroscopy, infrared spectroscopy, and scanning electron microscopy. Six chromatographic fractions from 0.3 to 102.8 kDa were obtained. The chemical and spectroscopic characterization results revealed the presence of protein-polysaccharide-ferulic acid complexes in four of the fractions. In the hydrolysate of a 15.1 kDa fraction, longitudinally fused nanospheres were found, forming chains. Occasionally, fusion occurred at different angles, providing attachment sites for branching. It is discussed how the composition of this fraction and the added Ca2+ ions could determine both the formation of the nanospheres and their arrangement.

RESUMEN El objetivo del presente trabajo fue explorar si la formación de nanopartículas proteicas, reportadas en un estudio previo, ocurre en una fracción de un extracto acuoso de salvado de trigo con composición particular. Utilizando una estrategia de abajo hacia arriba, primero se fraccionó un extracto acuoso de salvado de trigo mediante cromatografía de exclusión por tamaño. Cada una de las fracciones cromatográficas se hidrolizó con la proteasa V8 en un medio de reacción conteniendo Ca2+. Las fracciones cromatográficas y los hidrolizados de las mismas se sometieron a caracterización química, electroforesis, espectroscopía UV-Vis, espectroscopía infrarroja y microscopía electrónica de barrido. Se obtuvieron seis fracciones cromatográficas de 0.3 a 102.8 kDa. Los resultados de la caracterización química y espectroscópica revelaron la presencia de complejos proteína-polisacárido-ácido ferúlico en cuatro de las fracciones. En el hidrolizado de una fracción de 15.1 kDa se encontraron nanoesferas fusionadas longitudinalmente, formando cadenas. Ocasionalmente, la fusión se dio en diferentes ángulos, proporcionando sitios de unión para ramificaciones. Se discute cómo la composición de dicha fracción y los iones Ca2+ añadidos podrían determinar tanto la formación de las nanoesferas como su arreglo.

We evaluated the potential neuroprotective effect of 1-100 µM of four organoselenium compounds: diphenyl diselenide, 3’3-ditri-fluoromethyldiphenyl diselenide, p-methoxy-diphenyl diselenide, and p-chloro-diphenyl diselenide, against methylmercury-induced mitochondrial dysfunction and oxidative stress in mitochondrial-enriched fractions from adult Swiss mouse brain. Methylmercury (10-100 µM) significantly decreased mitochondrial activity, assessed by MTT reduction assay, in a dose-dependent manner, which occurred in parallel with increased glutathione oxidation, hydroperoxide formation (xylenol orange assay) and lipid peroxidation end-products (thiobarbituric acid reactive substances, TBARS). The co-incubation with diphenyl diselenide (100 µM) completely prevented the disruption of mitochondrial activity as well as the increase in TBARS levels caused by methylmercury. The compound 3’3-ditrifluoromethyldiphenyl diselenide provided a partial but significant protection against methylmercury-induced mitochondrial dysfunction (45.4 ± 5.8% inhibition of the methylmercury effect). Diphenyl diselenide showed a higher thiol peroxidase activity compared to the other three compounds. Catalase blocked methylmercury-induced TBARS, pointing to hydrogen peroxide as a vector during methylmercury toxicity in this model. This result also suggests that thiol peroxidase activity of organoselenium compounds accounts for their protective actions against methylmercury-induced oxidative stress. Our results show that diphenyl diselenide and potentially other organoselenium compounds may represent important molecules in the search for an improved therapy against the deleterious effects of methylmercury as well as other mercury compounds.

In recent years, the nanomaterials have been proposed like a new option to increase the cellular response onto dental and orthopedic implants. With this in mind, it has been developed a study to investigate the effect of the nanotopography of one ceramic compound on the biomineralization process. In this case we use zinc aluminate films, deposited by spray pyrolysis technique, with nanometer sized morphologies. The obtained results, when culture osteoblastic cells onto nanoceramics, indicated that the nanometer sized surface of the proposed material increased the cellular adherence, as compared with the surfaces of the reference material. From the above-mentioned result, it can be deduced that the nanometer sized surface changes the properties of the ceramic material to behave as a material with a bioactive surface. This bioactivity is manifested with the increment in the biomineralization of the extracellular matrix and in the orderly rise of the mineral tissue deposited. According to the obtained results, we propose to the zinc aluminate films like a biocompatible ceramic which provides a similar nanometer sized ambient comparable with that of the human bone where biomineralization is favored. Such films can be applied on the implant materials in the dental and orthopedic area in our country.

Las cerámicas nanoestructuradas en película delgada se han propuesto como una nueva opción de recubrimientos en implantes ortopédicos y dentales. Con esto en mente, se realizó un estudio para investigar el efecto de la nanotopografía en el proceso de biomineralización por medio de la preparación de películas delgadas con base en el aluminato de cinc con morfología nanométrica por el método de rocío pirolítico. Los resultados obtenidos al cultivar células osteoblásticas en las nanocerámicas, indicaron que la superficie nanométrica del material propuesto incrementa la adhesión celular cuando se comparan con las superficies del material control. Se puede argumentar que la superficie en rangos nanométricos cambia las propiedades del material cerámico al comportarse como un material con superficie bioactiva. Esta bioactividad se demuestra con el incremento en la biomineralización de la matriz extracelular y en el incremento ordenado del tejido mineral depositado. Por los resultados obtenidos, se propone al aluminato de cinc nanoestructurado como una cerámica biocompatible que proporciona un ambiente nanoestructurado similar al hueso favoreciendo la formación de mineral y la cual puede aplicarse en un futuro como recubrimiento de materiales de implante en el área dental y ortopédica en México.