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

A notable characteristic of Streptomyces bacteria is their ability to produce secondary metabolites. The aims of this study were to identify streptomycetes that exert antibacterial activity against plant and human pathogenic bacteria, and to evaluate antibiotic production in various culture media. To identify streptomycetes that exert broad antibacterial activity using the agar-disk diffusion method, 31 isolates were screened, after which a selected isolate was cultured in nine different growth media to evaluate the production of inhibitory metabolites. Three streptomycete isolates were identified that exert inhibitory activity against at least four pathogens species. The Y15 isolate showed broad antibacterial activity on Escherichia coli, Staphylococcus epidermidis, Listeria monocytogenes, Staphylococcus aureus, Pseudomonas syringae pv. phaseolicola, Dickeya dadantii, and Pectobacterium carotovorum. The production rate of antimicrobial metabolites was maintained when Y15 was grown in culture media containing limited organic nitrogen sources. The presence of organic nitrogen compounds in the media decreased the production of antibacterial metabolites. The Y15 isolate was identified by 16S rDNA gene sequencing as member of the genus Streptomyces. We show that the composition of the fermentation medium is likely an important factor for modulating antibiotic production by streptomycetes, with impacts on the quantity and diversity of antimicrobial metabolites production.

Child Development Centers aim to provide multidisciplinary care for the population of children, a sector particularly susceptible to respiratory diseases due to the presence of fungal microorganisms that are dispersed by air currents in the spaces where users are. Therefore, the objectives of this work were to evaluate the fungal concentration of the indoor air of the Child Development Center of the University of Sonora, identify the taxonomy of the isolates and describe the possible pathogenicity for human health. From May 2 to May 27, 89 samples were taken from 17 places where minors are present and from a control point. Static samplings were carried out at a height of one meter, using SAS SUPER 100 equipment and sedimentation on Petri dishes with Agar Sabouraud culture medium. By the imprint technique, 14 fungal genera were identified. Among the predominant ones are Cladosporium spp., Aspergillus spp. and Penicillium spp., with 31%, 26% and 16%, respectively. The highest fungal concentration detected was 53 CFU/m3, a value lower than considered dangerous due to indoor air pollution by various government institutions around the world. However, species of clinical interest of the genus Aspergillus were identified, with A. niger predominant in all the sites, followed by A. ochraceus, A. flavus, A. versicolor and A. fumigatus.

At 2020 Mexico exports around 24% of the national mango production, it is industrialized from 13 to 16%, and the rest is sold as fresh fruit. However, despite its low processing, the waste generated by the mango industry (32-50%) is a source of environmental pollution. In addition, losses add up of fresh fruit (30-50%) associated with the post-harvest handling and commercialization problems. The exploitation of mango-biomass not used represents a potential for elaborate byproducts to give it added value and promote the economic development of the regions that produce this fruit, where the pectin can be a good value-added alternative with yields of 15 to 32%. Nowadays one kilogram of commercial pectin in the market can cost $1,000.00 pesos. In addition, fiber, and phenols with potential use in the pharmaceutical, cosmetic, and food industries can be obtained from the remaining biomass. The compilation of what is known about pectin content in mango peel from different cultivars, a brief analysis of the current pectin market, and the most efficient extraction methods were objectives of this review.

Currently, food safety is the main objective of the food industry without neglecting its sensory and nutritional quality, so the emerging technologies are presented as an alternative to conventional ones, in order to correct, avoid or reduce the modification of texture, color and development of undesirable flavors generated by thermally treating foods. Therefore, in this paper non-thermal emerging technologies are shown, such as: high hydrostatic pressure, electrical pulses, high-frequency ultrasound, ionizing radiation and cold plasma, as well as their mechanisms for inactivating microorganisms. A brief review of the advantages and disadvantages of the application of these technologies in food is made and finally the areas of opportunity that drive the development and widespread application of emerging non-thermal technologies are presented.

La producción de cultivo de algodón en el Valle de Mexicali se ve afectada principalmente por enfermedades que marchitan y pudren la raíz, y son asociadas al hongo Fusarium spp. El presente trabajo tuvo como objetivo evaluar el efecto de la inoculación de Fusarium solani en cuatro cepas y conocer el porcentaje de la severidad del daño en plántulas de algodón transgénico. Los resultados indicaron que las cepas T-ICA03 y T-ICA01 presentaron un 90% de daños, así como un mayor número de puntos de infección en el sistema radicular en comparación con las otras cepas evaluadas. En plantas de 20 días de edad se determinó la eficiencia fotosintética y clorofílica observando cambios significativos entre las cepas inoculadas y el control durante el experimento. Ambos parámetros fisiológicos explican los posibles efectos de la infección a nivel del transporte de nutrientes y agua que impacta negativamente al sistema fotosintético de la planta. No obstante, debido a su especificidad, se recomienda principalmente el uso de la eficacia fotosintética como un parámetro no destructivo para evaluar el daño a nivel del fotosistema causado por la infección de F. solani en las plantas de algodón transgénico. 

In 1909, Carlos Justiniano Chagas first described the clinical manifestations of Chagas disease. The hemoflagellate parasite Trypanosoma cruzi (agent) is characterized by the presence of a flagellum and of a cytostome, glycosomes, reservosomes, and a nucleus in its cytoplasm. The life cycle of T. cruzi begins when a vector defecates on the skin of a host; the feces contain metacyclic trypomastigotes, which infect vertebrate cells. The vectors of this disease are members of the subfamily Triatominae, nocturnal, hematophagous insects capable of locating hosts by heat detection. T. cruzi infection has effects on the biology of the triatomine insect, its behavior, gut function, immune system, and associated microbiota. In the mammalian host, the parasite activates innate immune responses, and host cytokines are key to either control the infection or progress to chronicity. T. cruzi exhibits a wide genetic diversity, and while it has been proved under laboratory conditions to show varying degrees if virulence and organ tropism, no clear association has been found between specific strains and the clinical picture of the disease. This review addresses the history of the discovery of Chagas disease and discusses recent aspects of T. cruzi biology that provide insight into the dynamics of transmission.

In the present study, the biosorption of hexavalent chromium [Cr (VI)] was investigated using a by-product of nanche (Byrsonima crassifolia) in aqueous solutions by the batch method, parameters such as solutions pH, initial concentration of Cr (VI), adsorbent dose, particle size and contact time were evaluated. The results obtained showed that there is a greater removal of Cr (VI) with an acidic pH in the solution, using a particle size < 2.00 mm and increasing the adsorbent dose in batch biosorption, in addition, a total removal of Cr (VI) was obtained under the following parameters: 50 mg/L of Cr (VI), 1 g of adsorbent / 30 mL, pH: 2.0, particle size between 2.00-2.38 mm and a contact time of one hour. From the adjustment of kinetic models, it was determined that the Pseudo-second order model better describes the adsorption kinetics. In general, the by-product of nanche can be considered an adsorbent with the ability to remove Cr (VI) from aqueous solutions.

The wastewater from a milking parlor is made up of solid and liquids waste. For the treatment of these residues, microorganisms such as Saccharomyces cerevisiae (SC), lactic acid bacteria (LAB) and species of the genus Bacillus were used. For this reason, in this work it was treated the wastewater of a milking parlor applying microbial mixtures (MM). The test was carried out under a randomized design, with three replicates per analysis and mixtures (MM1 (SC-LAB) and MM2 (Bacillus species)), divided into two parts in which were measured: pH, soluble solids, electrical conductivity (EC), Total Dissolved Solids (TDS) and the plate count of the microorganisms under study and total coliforms (TC). The first part was performed in Erlenmeyer flasks, inoculating the MMs into 100 mL of liquid waste in different flasks. While in the second part, the most efficient mixture was applied in situ, collecting the samples weekly. Analysis of variance (ANOVA, α = 0.05) and the test of the least significant difference (LSD) were performed on the data collected. In this research, the MM2 (applied in situ) managed to reduce EC (from 1,800 to 1,100 μs/cm) and TDS (from 812 to 687 ppm), as well as inhibit the TC growth.

Metabolic syndrome (MetS) is a complex global public health problem, and related diseases are a cause of death, which in 2020 was 43%. Treatment and prevention of MetS without drugs have a significant impact by addressing the problem comprehensively. With lifestyle changes, modifying the diet to include bioactive compounds that favor the gut microbiota (IM) and increased physical activity. Because of the IM role in the pathogenesis of MetS, probiotics and prebiotics are incorporated into the diet individually or mixed with foods or supplements in recent years. The present review defines the role of prebiotics in modifying the microbiota for the treatment and prevention of this condition.

Currently, food provision requires new tools that allow increasing the productivity of crops, without negative impacts on the environment. The plant rhizosphere is the soil part highly influenced by the root secretions. In this area, there is a high microbial activity, where different microorganisms, with agronomic applications, can live, and these can be used to develop products that contribute to face the challenges of current agriculture, such as the case of the bacterium Bacillus subtilis and different fungi species of the Trichoderma genus, which have been widely studied and used for the benefits that they give to plants. In this review, general characteristics of these microorganisms are described and the capacities these possess for their application in agricultural production, like an eco-friendly tool that helps to achieve food sovereignty, without the use of chemical compounds.