The contamination of both soil and water by nitrobenzene (NB) is a problem that has been studied, where several reactive agents have been developed for the degradation of this compound as well as different methods. Nanoparticles with semiconductive properties have been studied for organic compounds photodegradation due to their assistance in optimizing the degradation processes. Two of the most promising photocatalysts are ZnO and TiO₂ because of their optimal results. In the present work the performance of the zinc peroxide (ZnO₂) nanoparticles was evaluated. ZnO₂ nanoparticles were synthesized from zinc acetate and hydrogen peroxide using the Sol-Gel method under ultrasound assistance. The characterization was carried out by UV–Vis spectroscopy, infrared Fourier transform total reflectance (ATR-FT-IR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), Zeta potential, dynamic light scattering (DLS), field emission scanning electron microscopy (FE-SEM), and Energy Dispersive X-ray spectroscopy (EDX). The experiments for the degradation of NB were carried out in a photoreactor with UV lamps of 254 nm at 25 °C, using a solution of nitrobenzene with the nanoparticles. The best conditions for NB photodegradation were 30 ppm (ZnO₂) and 15 ppm (NB) at pH 2, reaching up to 90% degradation in 2 h. The intermediates formed during the photodegradation of NB were identified by gas chromatography mass spectrometry.

Fresh cheese represents a staple food of great importance for some communities, as well as an income from its commercialization; however, in some cases, the way it is processed could represent a risk to human health. Therefore, the objective of this study was to determine the sanitary quality of unpasteurized fresh cheeses intended for human consumption in Sinaloa. A total of 15, 20, 10, and 15 cheese samples were taken from Mazatlán, Culiacán, Guasave, and Los Mochis in the state of Sinaloa, México, respectively. The microbiological analysis was performed based on the Official Mexican Standard NOM-210-SSA1-2014. In accordance with the standard, the content of Escherichia coli, Staphylococcus aureus and Salmonella spp. was estimated. Of the total samples analyzed, 97% showed Escherichia coli, 57% S. aureus, and 13% Salmonella spp., above the reference values. The presence of indicator microorganisms and pathogens represents a risk factor for acquiring foodborne diseases, and also makes evident the need to improve hygienic practices in the preparation and preservation of these products.

Paratuberculosis is a disease caused by Mycobacterium avium subsp. paratuberculosis (MAP). It is of great interest to better understand the proteins involved in the pathogenicity of this organism in order to be able to identify potential therapeutic targets and design new vaccines. The protein of interest–MAP3773c–was investigated, and molecular modeling in silico, docking, cloning, expression, purification, and partial characterization of the recombinant protein were achieved. In the in silico study, it was shown that MAP3773c of MAP has 34% sequence similarity with Mycobacterium tuberculosis (MTB) FurB, which is a zinc uptake regulator (Zur) protein. The docking data showed that MAP3773c exhibits two metal-binding sites. The presence of structural Zn²⁺ in the purified protein was confirmed by SDS-PAGE PAR staining. The purification showed one band that corresponded to a monomer, which was confirmed by liquid chromatography–mass spectrometry (LC-MS). The presence of a monomer was verified by analyzing the native protein structure through BN-SDS-PAGE (Native Blue (BN) Two-Dimensional Electrophoresis) and BN–Western blotting. The MAP3773c protein contains structural zinc. In conclusion, our results show that MAP3773c displays the features of a Fur-type protein with two metal-binding sites, one of them coordinating structural Zn²⁺.