Determining the Photoelectrical Behavior and Photocatalytic Activity of an h-YMnO3 New Type of Obelisk-like Perovskite in the Degradation of Malachite Green Dye.

YMnO3 is a P-type semiconductor with a perovskite-type structure (ABO3). It presents two crystalline systems: rhombohedral and hexagonal, the latter being the most stable and studied. In the hexagonal system, Mn3+ ions are coordinated by five oxygen ions forming a trigonal bipyramid, and the Y3+ ions are coordinated by five oxygen ions. This arrangement favors its ferroelectric and ferromagnetic properties, which have been widely studied since 1963. However, applications based on their optical properties have yet to be explored. This work evaluates the photoelectric response and the photocatalytic activity of yttrium manganite in visible spectrum wavelengths. To conduct this, a rod-obelisk-shaped yttrium manganite with a reduced indirect bandgap value of 1.43 eV in its hexagonal phase was synthesized through the precipitation method. The synthesized yttrium manganite was elucidated by solid-state techniques, such as DRX, XPS, and UV-vis. It was non-toxic as shown by the 100% leukocyte viability of mice BALB/c.

Nanohybrid of Thymol and 2D Simonkolleite Enhances Inhibition of Bacterial Growth, Biofilm Formation, and Free Radicals.

Due to the current concerns against opportunistic pathogens and the challenge of antimicrobial resistance worldwide, alternatives to control pathogen growth are required. In this sense, this work offers a new nanohybrid composed of zinc-layered hydroxide salt (Simonkolleite) and thymol for preventing bacterial growth. Materials were characterized with XRD diffraction, FTIR and UV-Vis spectra, SEM microscopy, and dynamic light scattering. It was confirmed that the Simonkolleite structure was obtained, and thymol was adsorbed on the hydroxide in a web-like manner, with a concentration of 0.863 mg thymol/mg of ZnLHS. Absorption kinetics was described with non-linear models, and a pseudo-second-order equation was the best fit. The antibacterial test was conducted against Escherichia coli O157:H7 and Staphylococcus aureus strains, producing inhibition halos of 21 and 24 mm, respectively, with a 10 mg/mL solution of thymol-ZnLHS. Moreover, biofilm formation of Pseudomonas aeruginosa inhibition was tested, with over 90% inhibition. Nanohybrids exhibited antioxidant activity with ABTS and DPPH evaluations, confirming the presence of the biomolecule in the inorganic matrix. These results can be used to develop a thymol protection vehicle for applications in food, pharmaceutics, odontology, or biomedical industries.

Improved extraction of carrageenan from red seaweed (Chondracantus canaliculatus) using ultrasound-assisted methods and evaluation of the yield, physicochemical properties and functional groups.

Red seaweed Chondracanthus canaliculatus, an underexploited algae species, was used as a potential source for the obtaining of carrageenan. Seaweed was treated under alkaline conditions using ultrasound alone or combined with conventional procedures, to improve the yield extraction. Color, syneresis behavior, water retention capacity, and functional groups of the gelling and non-gelling fractions of carrageenan were determined; these properties were compared with those of commercial carrageenans named A and B. Ultrasound alone or with heat significantly (p < 0.05) increased the yield extraction up to 41-45% and influenced color parameters, in comparison with conventional treatments. Functional groups kappa and iota, and alginates, were confirmed in both carrageenan fractions. Syneresis behavior was well fitted to a third-degree polynomial equation within days 1 to 6, after which, it reached a plateau. While, the use of ultrasound at room temperature gave carrageenan properties more similar to those of the commercial carrageenan type A.

Clostridium perfringens as Foodborne Pathogen in Broiler Production: Pathophysiology and Potential Strategies for Controlling Necrotic Enteritis.

Clostridium perfringens (Cp.) is the cause of human foodborne desease. Meat and poultry products are identified as the main source of infection for humans. Cp. can be found in poultry litter, feces, soil, dust, and healthy birds' intestinal contents. Cp. strains are known to secrete over 20 identified toxins and enzymes that could potentially be the principal virulence factors, capable of degrading mucin, affecting enterocytes, and the small intestine epithelium, involved in necrotic enteritis (NE) pathophysiology, also leading to immunological responses, microbiota modification and anatomical changes. Different environmental and dietary factors can determine the colonization of this microorganism. It has been observed that the incidence of Cp-associated to NE in broilers has increased in countries that have stopped using antibiotic growth promoters. Since the banning of such antibiotic growth promoters, several strategies for Cp. control have been proposed, including dietary modifications, probiotics, prebiotics, synbiotics, phytogenics, organic acids, and vaccines. However, there are aspects of the pathology that still need to be clarified to establish better actions to control and prevention. This paper reviews the current knowledge about Cp. as foodborne pathogen, the pathophysiology of NE, and recent findings on potential strategies for its control.

Chemical and biological protection of food grade nisin through their partial intercalation in laminar hydroxide salts.

The use of antimicrobial agents within a matrix, specifically layered compounds, is of growing interest for reducing contamination due to food borne pathogens and deteriorative microorganisms, one of the main health problems worldwide. In this study, zinc layered hydroxide nanoparticles were synthesized as a matrix for nisin immobilization. Layered materials were characterized by X-ray diffraction, Fourier-Transform Infrared and Ultra Violet-Visible spectra, Scanning Electron Microscopy, and by Thermogravimetric Analysis. Thermal, chemical, enzymatic, and biological stabilities were assessed against Lactobacillus brevis as control strain. Free and immobilized nisin in solution were previously subjected to 25 and 121 °C, pH (7, 9) and inactivation with protease before antimicrobial tests that lasted 21 days. Immobilized nisin was found to maintain the activity levels after the protease action while the pure nisin solution lost its activity gradually. Furthermore, immobilized nisin treated at 121 °C and pH 7 showed higher activity than pure nisin after 21 days. These results may support that immobilizing nisin in zinc layered hydroxide salts promoted extended nisin inhibitory activity in solution after thermal, chemical or enzymatic treatments. This research provides an alternative to nisin application that could be used in processes where such operating conditions take place, as in dairy products.

Immobilizing yeast ß-glucan on zinc-layered hydroxide nanoparticle improves innate immune response in fish leukocytes.

Nanoparticle-based delivery technologies have played a central role in a wide variety of applications, including cell therapy, gene transformation, and cellular delivery of molecular dyes. This work synthesized via ionic exchange a nanoparticle consisting of zinc-layered hydroxychloride coupled with yeast ß-glucan (ZG), whose cellular immune response was evaluated using fish spleen leukocytes. Leukocytes from the marine Pacific red snapper (Lutjanus peru) were stimulated with zinc-layered hydroxychloride (ZHC) coupled with yeast ß-glucan (GLU) and challenged with live Vibrio parahaemolyticus after 24 h. Structural characterization of this yeast glucan by proton nuclear magnetic resonance (NMR) indicated structures containing (1-6)-branched (1-3)-ß-D-glucan. The ZHC and ZG were characterized with X-ray diffraction, infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. The results of the immunological study showed that ZHC, GLU or ZG were safe for leukocytes because cell viability was higher than 80% compared with DMSO or V. parahaemolyticus exposure. The ZG or GLU treatments enhanced nitric oxide production, superoxide dismutase, catalase and peroxidase activities. Induction of anti- and pro-inflammatory cytokine (IL-1ß, IL-6, IL-8, IL-10, IL-12 and IL-17) genes was more pronounced in ZG or GLU treatments compared to the other groups. Based on the results, ZHC nanoparticles can be used as a delivery carrier of yeast ß-glucan for enhancing immunity in fish and have great potential application in the aquaculture industry.