Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

In this work, the determination of α- and γ-tocopherol in oil extracted from prickly pear seeds (Opuntia ficus-indica) was carried out. The extraction was performed using solvent extraction methods (Soxhlet) and microwave-assisted extraction, with alcohol, hexane, methanol, and water as solvents. The tocopherols amount obtained in micrograms was determined to compare the performance of each extraction method, as well as the solvents used. The amounts of α-tocopherol and γ-tocopherol were determined by the HPLC method. In addition, the saponification index was determined to analyze the purity and quality of the oil, with the best value being 167.08 mg KOH/g. The acidity index was used to verify the shelf life of the oil, where the best values are those below 0.05 %. FTIR was used to determine the functional groups present in each sample. The use of ethanol as a solvent in both methods was found to produce a higher yield of γ-tocopherol (266.93 μg/g dw).

The origin and major center of Jala maize cultivation is located in Jala, Nayarit, Mexico.  This landrace has characteristics allowing for varied use, including use in an annual contest for the longest corn in the world.  This study was carried out to analyze changes through time in the distinctive characteristics of this landrace, which are the length of both corn and cob, and to relate the contest with its in situ conservation. Data from a survey of 24 Jala landrace-growing producers applied in 2017 were used.  In 2012 and 2023 phenotypic descriptors were derived from cobs harvested in situ.  Additional interviews were conducted and some information was systematized based on participation in corn contest coordination.  The maximum corn length recorded since 1981 was obtained in 2023 and it was 49 cm. In 2023, a 50 cm cob was produced. It was lower than the maximum recorded in 1907 (55.9 cm). The recorded corn lengths were relatively stable over time; however, they do not provide elements to assert whether the contest contributes to improving the expression of cob length, because there are no harvest records derived from field producers.  A decrease in the current area cultivated with Jala landrace threatens in situ conservation. Tradition, focused on the corn contest is fundamental for the in situ conservation of this unique worldwide plant genetic resource.

Phenolic compounds are found in plants and have a high antioxidant capacity. Various methodologies have been reported for the Quantification of Total Phenols, however, it is common that the effect of small modifications of the various variables involved in the procedure is not evaluated. For this reason, in this work it is proposed to optimize the various variables of the analysis, perform the validation and evaluate its application in plant extracts. Water was selected as the dissolution medium and the reaction volume was reduced to 200 µL. The volume of the Folin-Ciocalteau reagent (33.5 µL), the volume of 20% sodium carbonate (86.5 µL) and the reaction time (46.5 min) were optimized. Under these conditions, calibration curves were made and linearity, precision and accuracy, the Detection Limit and the Quantification Limit were established. The robustness of the method and the effect of the matrix were evaluated, determining that the method is robust, but there is matrix interference. It was concluded that quantification should be performed by a standard addition curve.

Top predators are essential for ecosystems, and their absence can trigger trophic cascades. In Punta de Mita, Nayarit, Mexico, tourist urbanization, livestock farming, and road infrastructure threaten the presence of the jaguar (Panthera onca) and the puma (Puma concolor). From April to June 2023, 36 camera traps were set up to determine the presence and relative abundance of jaguar and puma in an area surrounded by roads and subject to intense human disturbance. With a sampling effort of 1,291 trap-days, 1,975 independent photographic records were obtained. A total of 11 species of medium and large wild mammals were recorded. The most abundant species were the coati (Nasua narica) and the white-tailed deer (Odocoileus virginianus). No records of jaguars or pumas were obtained, which could be related to habitat loss and fragmentation due to livestock activities and road presence, as well as detection difficulties caused by their low densities. The coati, collared peccary, and raccoon were more abundant than in other studies where large predators were recorded. This highlights the need for long-term studies to understand the effects of the absence of large predators in fragmented ecosystems.

This study investigates the impact of molecular aggregation on the multicomponent adsorption of pharmaceuticals. Acetaminophen, diclofenac, and naproxen were selected. Density Functional Theory calculations were performed to analyze the thermodynamic feasibility of dimer and trimer formation for both homogenous and heterogeneous combinations. Molecular electrostatic potential and dual descriptor analyses provided insights into the reactive sites and the stability of these aggregates. Results indicate that dimer formation is thermodynamically favorable, particularly for NAP. The calculated interaction energies and distances for dimers and trimers offer a quantitative understanding of the aggregation behavior. This theoretical framework reveals how molecular aggregation influences the competitive adsorption of pharmaceuticals, providing crucial insights into the design of more effective water treatment strategies.

The environmental impact of plastics has motivated the search for biotechnological strategies for their degradation. This study isolated and characterized microorganisms with hydrolytic and oxidoreductase enzymatic activity from a contaminated site in Nayarit, Mexico, called Arena Cora. 23 plastic waste samples were collected, isolating 172 strains. A preliminary screening of halo formation in a solid medium at 30°C for 48h was performed to identify extracellular enzymes, followed by quantification through submerged fermentation at 30°C, 150 rpm for 72h, both with inducers. Identification was carried out using MALDI-TOF mass spectrometry. The enzymatic screening in solid medium identified 22 strains with relevant activity, with Bacillus (76.4%) and Pseudomonas (11.8%) being the most prevalent genera. The most frequent activities were esterase/lipase and hydrolase, with 48 and 34 positive strains, respectively. 6.4% of these strains reached the highest activity levels. Furthermore, five strains with cutinase activity and 15 with laccase activity were identified. Submerged fermentation confirmed the production of hydrolytic and oxidoreductase extracellular enzymes. B. subtilis (A55A) exhibited the highest induced activity with tributyrin and mineral oil, reaching over 120 U/mL at 24h. B. cereus (A41C) showed the highest cutinase activity (17.05 U/mL at 72h). The highest laccase production was observed in strain A46E (10.3 U/mL at 72h). P. koreensis (A58F), with no prior records of plastic degradation, displayed lipase activity at 24h. These results highlight the potential of native microorganisms in plastic biodegradation and their potential application in bioremediation strategies.

The aim of this work was to analyze the anthropogenic effects on native shrimp populations through documentary evidence. To do so, an analysis of documents detected in databases that addressed anthropogenic factors on these species was carried out. In addition, surveys were conducted among local inhabitants to collect information on the use of the species and the anthropogenic effects identified by the communities. Additionally, the nutritional quality of the muscle of Macrobrachium tenellum was analyzed through chemical computation to determine its protein quality based on essential amino acids. The research identified six main factors that threaten M. tenellum populations: habitat modification and fragmentation, water pollution from agricultural, industrial and urban activities, destructive fishing practices, introduction of invasive species, impacts of climate change and alterations in the intestinal microbiome. The nutritional analysis showed that the protein of M. tenellum is of high quality, with adequate amounts of essential amino acids. There is a clear need to implement a holistic conservation approach that integrates environmental protection measures, sustainable management and socioeconomic considerations to ensure the preservation of the species and the well-being of dependent communities.

This work presents a series of experiments aimed at anchoring silver (Ag) and gold (Au) nanoparticles on graphene oxide (GO). In a first stage, the synthesis of colloidal nanoparticles was carried out using the Turkevich method, employing sodium citrate as reducing and stabilizing agent. Subsequently, the anchoring of the nanoparticles to the OG was implemented, which was synthesized using Hummers' method, involving the oxidation of graphite using potassium permanganate (KMnO4), sodium nitrate (NaNO3) and sulfuric acid (H2SO4). For anchoring, two methodologies were developed: (1) mixing of a solution of Au or Ag nanoparticles with graphene oxide, and (2) in-situ synthesis of the nanoparticles in an OG solution. The obtained samples were characterized by ultraviolet-visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), dynamic light scattering (DLS) and powder X-ray diffraction (XRD). The results indicate that both methods are effective for nanoparticle anchoring, showing homogeneous distributions and good structural properties. This study provides a basis for the development of functional materials based on graphene and metal nanoparticles, with potential in catalytic and technological applications.

Essential oils (EO´s) have been used since ancient times in the health field. They are extracted from aromatic plants and are mainly composed of terpenes and many organic compounds. Pennyroyal (Lippia alba) is a plant of the Verbenaceae family that synthesizes essential oil (EO) with diverse properties in medical therapy and this bioactivity varies according to the evaluated chemotype. A review and compilation of scientific information was carried out on the antibacterial, antifungal, anti-inflammatory and antioxidant properties in vitro of the EO of the seven L. alba chemotypes registered from 2010 to date, in databases such as PubMed, Scielo, Elsevier and Springer, using keywords such as Lippia alba, essential oil, antibacterial activity and antifungal activity. Among other. The review demonstrates the impact of the bioactivity of L. alba EO, as well as the effectiveness of the chemotypes against a range of human pathogens, as well as their anti-inflammatory and antioxidant properties.

Agronomic management in the meadow directly affects the performance, nutritional value, morphological and structural characteristics of the pastures. The objective was to evaluate the productive behavior of Mulato II grass at different cutting intervals and intensity. Different intervals (2, 4, 6, 8, 10 and 12 weeks) and cutting intensities (10 and 20 cm) were evaluated using a randomized complete block de-sign. The yield, morphological composition, nutritional value, growth rate, morphological and structural characteristics were evaluated. The highest plant height was obtained at an interval of 10 weeks with an average of 101 cm at an intensity of 20 cm. The total dry matter yield was higher at an interval of 10 and 12 weeks (8011 and 7167 kg ha-1, respectively) at an intensity of 10 cm. The protein content was higher at an interval of four weeks at intensities of 10 and 20, and in the sixth week at an intensity of 10 cm, while the fiber and lignin content increased as the cutting interval increased. The Mulato II cultivar should be harvested at an interval of eight weeks at an intensity of 20 cm, since a higher protein content is obtained per ha.