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: <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

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

Métodos analíticos para determinación de compuestos emergentes en agua

MARTHA AVILES FLORES (2016, [Documento de trabajo])

En este proyecto se implementan, desarrollan y validan métodos analíticos para identificar y cuantificar contaminantes emergentes en agua por cromatografía líquida – detector de masas triple cuádruplo, comprobando su aplicabilidad con muestras de agua de pozo, agua de río y agua residual de una planta de tratamiento de distintos estados del país.

Contaminantes emergentes Antibióticos Contaminación del agua Cromatrografía líquida INGENIERÍA Y TECNOLOGÍA

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

Métodos analíticos para determinación de compuestos emergentes en agua

MARTHA AVILÉS FLORES NORMA RAMIREZ SALINAS (2014, [Documento de trabajo])

Los objetivos principales de este proyecto fueron: 1) desarrollar e implementar metodologías para la identificación y cuantificación de compuestos emergentes en aguas subterráneas y superficiales; y 2) Evaluar la correlación entre los parámetros de color verdadero, absorbancia en el rango de UV, COT y compuestos orgánicos con muestras sintéticas.

Contaminación del agua Contaminantes emergentes Antibióticos Informes de proyectos INGENIERÍA Y TECNOLOGÍA

Publisher Correction: Gut microbiota mediate caffeine detoxification in the primary insect pest of coffee (Nature Communications, (2015), 6, 1, (7618), 10.1038/ncomms8618)

Javier A. Ceja-Navarro Fernando E. Vega Ulas Karaoz Zhao Hao Petr Kosina Francisco Infante Trent Northen Eoin Brodie (2023, [Artículo])

Antibiotic Frass Non Antibiotic CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA MICROBIAL FLORA PEST INSECTS HYPOTHENEMUS HAMPEI CAFFEINE

Chronic toxicity of shrimp feed added with silver nanoparticles (Argovit-4®) in Litopenaeus vannamei and immune response to white spot syndrome virus infection

Carlos Rosendo Romo Quiñonez Píndaro Álvarez Ruiz CLAUDIO HUMBERTO MEJIA RUIZ NINA BOGDANCHIKOVA Alexey Pestryakov CARINA GAMEZ JIMENEZ WENCESLAO VALENZUELA QUIÑONEZ Magnolia Montoya Mejía EUSEBIO NAVA PEREZ (2022, [Artículo])

"In recent years, the application of silver nanoparticles (AgNPs) as antibacterial compounds has been widely used in human and veterinary medicine. In this work, we investigated the effects of AgNPs (Argovit-4 R ) as feed additives (feed-AgNPs) on shrimp (Litopenaeus vannamei) using three different methods: 1) chronic toxicity after 28 days of feeding, 2) Effects against white spot syndrome virus (WSSV) challenged by oral route, and 3) transcriptional responses of immune-related genes (PAP, ProPO, CTL-3, Crustin, PEN3, and PEN4) following WSSV infection. The results showed that the feed-AgNPs did not interfere with the growth and survival of shrimp. Also, mild lesions in the hepatopancreas were recorded, proportional to the frequency of the feed-AgNP supply. Challenge test versus WSSV showed that feeding every 7 days with feed-AgNPs reduced mortality, reaching a survival rate of 53%, compared to the survival rates observed in groups fed every 4 days, daily and control groups of feed-AgNPs for the 30%, 10%, and 7% groups, respectively. Feed-AgNPs negatively regulated the expression of PAP, ProPO, and Crustin genes after 28 days of treatment and altered the transcriptional responses of PAP, ProPO, CTL-3, and Crustin after WSSV exposure. The results showed that weekly feeding-AgNPs could partially prevent WSSV infection in shrimp culture. However, whether or not transcriptional responses against pathogens are advantageous remains to be elucidated."

Silver nanoparticles, Shrimp, Aquaculture, Chronic toxicity, WSSV, AgNP, Argovit, Litopenaeus vannamei , Silver fed, White spot syndrome virus BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA INMUNOLOGÍA INMUNIZACIÓN INMUNIZACIÓN

“Mexico half way of making”: Carlos Chávez and the foundation of the National Institute of Fine Arts (INBA) (1945-1947)

Ana Garduño (2023, [Artículo, Artículo])

I am focusing on the interaction between a cultural agent, Carlos Chávez, and the government elite, related to the circumstances of the enunciation of a public and official organism, INBA (The National Institute of Fine Arts), because I assume that political relations are fundamental to understand a process that endorsed the official culture as an appendage of politics. In spite of its relevance, this subject has not been studied. Based on archival documentation (at the National Archive of Mexico and the archive of INBA) I am examining the cultural policies derived from the foundation of INBA. Due to the current pandemic situation, it was not possible to consult other documental sources. I am formulating that the concept of “high culture” was at the core of a wider conflict between governmental interests and those of representative social actors, and I conclude that this obstacle would have conferred a major political and symbolical importance to the Institute, and consequently, would restrict its budget.

Carlos Chávez INBA Agentes culturales Políticas institucionales Centralización artística HUMANIDADES Y CIENCIAS DE LA CONDUCTA HUMANIDADES Y CIENCIAS DE LA CONDUCTA Foundation of the National Institute of Fine Arts in Mexico (INBA), Cultural agents Institutional policies Artistic centralization

Farmers’ perspectives as determinants for adoption of conservation agriculture practices in Indo-Gangetic Plains of India

Ajay Kumar Mishra ML JAT (2022, [Artículo])

Understanding the farmer's perspective has traditionally been critical to influencing the adoption and out-scaling of CA-based climate-resilient practices. The objective of this study was to investigate the biophysical, socio-economic, and technical constraints in the adoption of CA by farmers in the Western- and Eastern-IGP, i.e., Karnal, Haryana, and Samastipur, Bihar, respectively. A pre-tested structured questionnaire was administered to 50 households practicing CA in Western- and Eastern-IGP. Smallholder farmers (<2 ha of landholding) in Karnal are 10% and Samastipur 66%. About 46% and 8% of households test soil periodically in Karnal and Samastipur, respectively. Results of PCA suggest economic profitability and soil health as core components from the farmer's motivational perspective in Karnal and Samastipur, respectively. Promotion and scaling up of CA technologies should be targeted per site-specific requirements, emphasizing biophysical resource availability, socio-economic constraints, and future impacts of such technology.

Smallholder Farmers Agents of Change Technology Diffusion Climate-Smart Practices CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA SMALLHOLDERS SOCIAL STRUCTURE IRRIGATION MANAGEMENT TECHNOLOGY CLIMATE-SMART AGRICULTURE CONSERVATION AGRICULTURE

Optimization of the alkali-silane treatment of agave lechuguilla fibers (ixtle) for potential reinforcement in polymeric composites

NOEMI JARDON MAXIMINO MARIAMNE DEHONOR GOMEZ Rolando Villa Moreno MARIA DOLORES BAEZA ALVARADO Luis Edmundo Lugo Uribe (2023, [Artículo])

Reinforced polymeric composites with natural fibers have garnered significant interest in recent years due to the need for biomass utilization and the requirements of various industries, such as automotive and construction. Among these natural fibers, Agave lechuguilla fiber, commonly known as ixtle (FIx) or Tampico fiber, exhibits important characteristics such as length, high strength, and durability. However, there is limited literature on its conditioning, functionalization, and utilization as a reinforcing material in polymeric composites (CP). This study presents the optimization of the alkali-silane treatment of FIx, identifying the most suitable reaction conditions to enhance their thermal stability, tensile strength, and silane coupling agent (ACSi) grafting on the fiber surface. The chemical treatment with ACSi proved highly effective, resulting in a significant grafting content, which was confirmed through FTIR and SEM–EDS analyses. The high level of functionalization did not compromise the mechanical performance of the fibers, suggesting that functionalized FIx holds great potential as a reinforcing material in CP. These findings open new paths for the sustainable use of Agave lechuguilla fibers, contributing to the development of environmentally friendly and high-performance polymeric composites in various industrial applications.

This article belongs to the Special Issue Natural Fibers for Advanced Materials: Addressing Challenges).

Supplementary materials: The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/fib11100086/s1, Figure S1: Optical microscope image of ixtle fibers at a magnification of 50 (a) untreated and (b) alkaline treated (FIx-5); Table S1: FTIR signal assignment for alkaline treated FIx; Table S2: FTIR Signal assignment for silane treated FIx.

Author contributions: Conceptualization, N.J.-M. and L.E.L.U.; methodology, N.J.-M., M.D.G., R.V.M., M.D.B.-A. and L.E.L.U.; validation, N.J.-M. and L.E.L.U.; formal analysis, N.J.-M., M.D.G. and L.E.L.U.; investigation, N.J.-M. and L.E.L.U.; data curation, N.J.-M., M.D.G., R.V.M. and M.D.B.-A.; writing—original draft preparation, N.J.-M. and L.E.L.U.; writing—review and editing, N.J.-M., M.D.G., R.V.M., M.D.B.-A. and L.E.L.U.; visualization, N.J.-M., M.D.G. and L.E.L.U.; supervision, L.E.L.U.; project administration, N.J.-M. and L.E.L.U.; funding acquisition, N.J.-M. and L.E.L.U. All authors have read and agreed to the published version of the manuscript.

Funding: This research was funded by CONAHCYT, “Estancias postdoctorales por México”, grant umber CVU425480.

Data availability statement: Data supporting the findings of this study are available within the article and upon request from the corresponding author.

Acknowledgments: The authors express their gratitude towards Rene Diaz Rebollar and Jazmin Gomez Sara for their technical assistance in conducting the chemical reactions presented in this current study. Additionally, the assistance provided by Luis Alberto Caceres Diaz in the execution of XRD analyses is also acknowledged. Furthermore, N.J.M. extends sincere recognition to CIATEQ A.C. for their provision of essential resources and infrastructure crucial to the advancement of this research. The support rendered by CONAHCYT through the “Estancias postdoctorales por México” program is also gratefully acknowledged, as it has contributed financial backing to the project. Conflicts of Interest: The authors declare no conflict of interest.

Agave lechuguilla Natural fiber Silane coupling agent INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS OTRAS ESPECIALIDADES TECNOLÓGICAS OTRAS OTRAS