Estudio de remoción en biofiltros no convencionales

Edson Baltazar Estrada Arriaga (2017, [Documento de trabajo])

La metodología utilizada para este estudio fue la implementación del método espectrofotométrico UV para la cuantificación de fármacos. Se presenta la forma del montaje del sistema de biofiltración y pruebas abióticas, así como su evaluación.

Remoción de contaminantes Filtros biológicos Compuestos orgánicos emergentes INGENIERÍA Y TECNOLOGÍA

Mulch application as the overarching factor explaining increase in soil organic carbon stocks under conservation agriculture in two 8-year-old experiments in Zimbabwe

Regis Chikowo Christian Thierfelder Marc Corbeels (2024, [Artículo])

Conservation agriculture (CA), combining reduced or no tillage, permanent soil cover, and improved rotations, is often promoted as a climate-smart practice. However, our understanding of the impact of CA and its respective three principles on top- and subsoil organic carbon stocks in the low-input cropping systems of sub-Saharan Africa is rather limited. This study was conducted at two long-term experimental sites established in Zimbabwe in 2013. The soil types were abruptic Lixisols at Domboshava Training Centre (DTC) and xanthic Ferralsol at the University of Zimbabwe farm (UZF). The following six treatments, which were replicated four times, were investigated: conventional tillage (CT), conventional tillage with rotation (CTR), no tillage (NT), no tillage with mulch (NTM), no tillage with rotation (NTR), and no tillage with mulch and rotation (NTMR). Maize (Zea mays L.) was the main crop, and treatments with rotation included cowpea (Vigna unguiculata L. Walp.). The soil organic carbon (SOC) concentration and soil bulk density were determined for samples taken from depths of 0–5, 5–10, 10–15, 15–20, 20–30, 30–40, 40–50, 50–75 and 75–100 cm. Cumulative organic inputs to the soil were also estimated for all treatments. SOC stocks at equivalent soil mass were significantly (p<0.05) higher in the NTM, NTR and NTMR treatments compared with the NT and CT treatments in the top 5 cm and top 10 cm layers at UZF, while SOC stocks were only significantly higher in the NTM and NTMR treatments compared with the NT and CT treatments in the top 5 cm at DTC. NT alone had a slightly negative impact on the top SOC stocks. Cumulative SOC stocks were not significantly different between treatments when considering the whole 100 cm soil profile. Our results show the overarching role of crop residue mulching in CA cropping systems with respect to enhancing SOC stocks but also that this effect is limited to the topsoil. The highest cumulative organic carbon inputs to the soil were observed in NTM treatments at the two sites, and this could probably explain the positive effect on SOC stocks. Moreover, our results show that the combination of at least two CA principles including mulch is required to increase SOC stocks in these low-nitrogen-input cropping systems.

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA SOIL ORGANIC CARBON CONSERVATION AGRICULTURE EXPERIMENTATION CROP MANAGEMENT

El mercurio y su uso histórico en México

Taryn Symon DANIELA ALEJANDRA MURILLO CISNEROS TANIA ZENTENO SAVIN (2022, [Artículo])

"El uso antropogénico del mercurio (Hg) para diversas funciones, incluso como pigmento y como remedios medicinales, se remonta a la antigüedad. Históricamente, las minas de Hg en la “Nueva España” (actualmente México) fueron explotadas en los actuales estados de Guerrero, Durango, Chihuahua, Guanajuato, San Luis Potosí, Aguascalientes y Querétaro. La invención del “proceso de patio” para el aislamiento de metales como el oro y la plata a través de la formación de amalgamas con Hg en la Nueva España proporcionó un método altamente rentable, de nivel industrial."

Ecotoxicología, metales pesados, Una Salud MEDICINA Y CIENCIAS DE LA SALUD CIENCIAS MÉDICAS TOXICOLOGÍA OTRAS OTRAS

Multiplication of native endomycorrhizae isolated from arid soils on organic substrates in wheat plants (Triticum aestivum)

JOSÉ RAFAEL PAREDES JÁCOME ROSALINDA MENDOZA VILLARREAL ROBERTO GREGORIO CHIQUITO CONTRERAS Luis Guillermo Hernández Montiel VALENTIN ROBLEDO TORRES Homero Ramírez Rodríguez (2023, [Artículo])

"Purpose Organic residues of coffee pulp, sugarcane bagasse and mature bovine manure are a source of organic matter and nutrients for the multiplication of endomycorrhizae consortia. Therefore, the purpose of this research is to multiply the AMFs in such substrates to decrease soil and water pollution. Method A pot experiment under greenhouse conditions was conducted in order to evaluate the influence of agricultural residues (C2-GEC, C3-PAR, C12-PRO, C14-ZAR) with different genera of endomycorrhizae isolated from semi-arid soils, 75 days after the crop was established. Agronomic characteristics and mineral content of N, K, Ca, Mg, and Fe in root and shoot were evaluated in wheat (Triticum aestivum). Results Multiplication of endomycorrhizae was influenced by the residue type. Greater production of spores was ob-served in the coffee pulp, followed by the sugarcane bagasse, where a higher colonization was obtained in combination of C2-GEC and C3-PAR consortia. This consortia combination also was one of those that have increased the content of N, K, Ca, Mg, and Fe in roots and shoots of wheat.Conclusion Combination of native endomycorrhiza substrates and consortia provides an alternative tool that benefits the physiology and nutrition of the plant to be used in sustainable agricultural production systems."

Coffee pulp, Sugarcane bagasse, Bovine manure, Mycorrhizal fungi, Organic waste CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS AGRONOMÍA FERTILIDAD DEL SUELO FERTILIDAD DEL SUELO

Fitorremediación asistida a través de bacterias, para suelos contaminados con metales pesados y plaguicidas

TANIA GÓMEZ MORALES (2023, [Otro, Trabajo terminal, especialidad])

El suelo es un recurso no renovable que nos proporciona diferentes beneficios, incluidos los servicios ecosistémicos. Sin embargo, actividades antropogénicas como la minería y la agricultura lo han contaminado. Las prácticas mineras y agrícolas liberan contaminantes como plaguicidas y metales pesados al suelo como contaminantes individuales o mezclas, generando importantes efectos adversos para el ambiente y la salud humana. Debido a esta problemática, se han desarrollado diferentes estrategias de remediación para sitios con presencia de estos co-contaminantes. Una de ellas es la fitorremediación asistida por bacterias, una técnica basada en la asociación de plantas y bacterias, donde ambos organismos se benefician y mejoran la eficiencia de la remediación.

Soil is a non-renewable resource that provides us with different benefits, including ecosystem services. However, anthropogenic activities such as mining and agriculture have contaminated it. Minery and agriculture practices release contaminants such as pesticides and heavy metals into the soil as individual pollutants or mixtures, generating important adverse environmental and human health effects. Due to this problem, different remediation strategies have been developed for sites with the presence of these co-contaminants; one of them is bacterial-assisted phytoremediation, a technique based on the association of plants and bacteria, where both organisms benefit and improve remediation efficiency.

BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA suelo, fitorremediación, bacterias, plaguicidas, metales pesados, co-contaminados. soil, phytoremediation, bacteria, pesticides, heavy metals, co-contaminated

Dual function of EDTA with silver nanoparticles for root canal treatment–A novel modification

JUAN MANUEL MARTINEZ ANDRADE (2018, [Artículo])

The chelating and antimicrobial capacity of a novel modification of 17% EDTA with silver nanoparticles (AgNPs) (EDTA-AgNPs) was evaluated in-vitro for root canal treatment (RCT). The EDTA-AgNPs solution was characterized by UV-Vis spectroscopy, ?-potential and high-resolution transmission electron microscopy (HRTEM). Antimicrobial capacity was evaluated against Candida albicans and Staphylococcus aureus in planktonic and biofilm cells by broth macrodilution (24 h) and XTT assays, (1, 10 and 30 min) respectively. The chelating capacity of EDTA-AgNPs was assessed indirectly (smear layer removal) and directly (demineralizing effect) in bovine dentin at two silver concentrations, 16 and 512 ?g/ ml at 1 and 10 minutes of exposure time. Smear layer removal was evaluated by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The demineralizing effect was determined by atomic absorption spectroscopy (AAS), microhardness test (MH) and X-ray diffractometer (XRD). Synthesized AgNPs were quasi-spherical in shape with an average size of 13.09 ± 8.05 nm. 17% EDTA-AgNPs was effective to inhibit C. albicans and S. aureus in planktonic and biofilm cultures. The smear layer removal and demineralizing effect were similar between 17% EDTA-AgNPs and 17% EDTA treatments. The 17% EDTA-AgNPs solution proved to be an effective antimicrobial agent, and has a similar chelating capacity to 17% EDTA alone. These in-vitro studies strongly suggest that EDTA-AgNPs could be used for effective smear layer removal, having an antimicrobial effect at the same time during RCT. © 2018 Martinez-Andrade et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

edetic acid, silver nanoparticle, edetic acid, metal nanoparticle, silver, antibacterial activity, antibiotic sensitivity, antifungal activity, antimicrobial activity, Article, atomic absorption spectrometry, atomic force microscopy, biofilm, bovine, BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA MICROBIOLOGÍA MICROBIOLOGÍA

Effect of antimicrobial nanocomposites on Vibrio cholerae lifestyles: Pellicle biofilm, planktonic and surface-attached biofilm

ANAID MEZA VILLEZCAS (2019, [Artículo])

Vibrio cholerae is an important human pathogen causing intestinal disease with a high incidence in developing countries. V. cholerae can switch between planktonic and biofilm lifestyles. Biofilm formation is determinant for transmission, virulence and antibiotic resistance. Due to the enhanced antibiotic resistance observed by bacterial pathogens, antimicrobial nanomaterials have been used to combat infections by stopping bacterial growth and preventing biofilm formation. In this study, the effect of the nanocomposites zeolite-embedded silver (Ag), copper (Cu), or zinc (Zn) nanoparticles (NPs) was evaluated in V. cholerae planktonic cells, and in two biofilm states: pellicle biofilm (PB), formed between air-liquid interphase, and surface-attached biofilm (SB), formed at solid-liquid interfaces. Each nanocomposite type had a distinctive antimicrobial effect altering each V. cholerae lifestyles differently. The ZEO-AgNPs nanocomposite inhibited PB formation at 4 μg/ml, and prevented SB formation and eliminated planktonic cells at 8 μg/ml. In contrast, the nanocomposites ZEO-CuNPs and ZEO-ZnNPs affect V. cholerae viability but did not completely avoid bacterial growth. At transcriptional level, depending on the nanoparticles and biofilm type, nanocomposites modified the relative expression of the vpsL, rbmA and bap1, genes involved in biofilm formation. Furthermore, the relative abundance of the outer membrane proteins OmpT, OmpU, OmpA and OmpW also differs among treatments in PB and SB. This work provides a basis for further study of the nanomaterials effect at structural, genetic and proteomic levels to understand the response mechanisms of V. cholerae against metallic nanoparticles. © 2019 Meza-Villezcas et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

bacterial protein, copper nanoparticle, nanocomposite, OmpT protein, OmpU protein, OmpW protein, outer membrane protein A, silver nanoparticle, unclassified drug, zeolite, zinc nanoparticle, antiinfective agent, copper, metal nanoparticle, nanocompos BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA MICROBIOLOGÍA MICROBIOLOGÍA

Enhancement of antibiotics antimicrobial activity due to the silver nanoparticles impact on the cell membrane

Roberto Vazquez-Munoz (2019, [Artículo])

The ability of microorganisms to generate resistance outcompetes with the generation of new and efficient antibiotics; therefore, it is critical to develop novel antibiotic agents and treatments to control bacterial infections. An alternative to this worldwide problem is the use of nanomaterials with antimicrobial properties. Silver nanoparticles (AgNPs) have been extensively studied due to their antimicrobial effect in different organisms. In this work, the synergistic antimicrobial effect of AgNPs and conventional antibiotics was assessed in Gram-positive and Gram-negative bacteria. AgNPs minimal inhibitory concentration was 10–12 μg mL-1 in all bacterial strains tested, regardless of their different susceptibility against antibiotics. Interestingly, a synergistic antimicrobial effect was observed when combining AgNPs and kanamycin according to the fractional inhibitory concentration index, FICI: &lt;0.5), an additive effect by combining AgNPs and chloramphenicol (FICI: 0.5 to 1), whereas no effect was found with AgNPs and β-lactam antibiotics combinations. Flow cytometry and TEM analysis showed that sublethal concentrations of AgNPs (6–7 μg mL-1) altered the bacterial membrane potential and caused ultrastructural damage, increasing the cell membrane permeability. No chemical interactions between AgNPs and antibiotics were detected. We propose an experimental supported mechanism of action by which combinatorial effect of antimicrobials drives synergy depending on their specific target, facilitated by membrane alterations generated by AgNPs. Our results provide a deeper understanding about the synergistic mechanism of AgNPs and antibiotics, aiming to combat antimicrobial infections efficiently, especially those by multi-drug resistant microorganisms, in order to mitigate the current crisis due to antibiotic resistance. © 2019 Vazquez-Muñoz et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

ampicillin, antibiotic agent, aztreonam, beta lactam antibiotic, biapenem, chloramphenicol, kanamycin, silver nanoparticle, silver nitrate, antiinfective agent, metal nanoparticle, silver, antibiotic sensitivity, antimicrobial activity, Article, bact BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOFÍSICA BIOFÍSICA