ABSTRACT
We synthesized silver nanoparticles using Rumex hymenosepalus root extract (Rh). Nanoparticles were subjected to a purification process and final product is a composite of Rh and silver nanoparticles (AgNPsC). Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to perform a microstructure study. Additionally, two fractions (RhA and RhB) were obtained from the original extract by filtration with tetrahydrofuran (THF); both fractions were analyzed using UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and 2,2-diphenyl-1-picrylhydrazyl (DPPH); total polyphenol content was also determined. Separate inhibition tests for AgNPsC and RhA and RhB were applied to Gram-positive bacteria, Gram-negative bacteria, and yeast (Candida albicans) using the well diffusion method. Extract fractions were found to have inhibitory effects only over Gram-positive bacteria, and silver nanoparticles showed inhibitory effects over all the evaluated microorganisms. Cytotoxicity was evaluated using the tetrazolium dye (MTT) assay in mononuclear peripheral blood cells. In addition, we assessment AgNPsC in THP-1 monocyte cell line, using the cell viability estimation by trypan blue dye exclusion test (TB) and Live/Dead (LD) cell viability assays by confocal microscopy.
Subject(s)
Anti-Infective Agents/pharmacology , Metal Nanoparticles/chemistry , Plant Extracts/chemistry , Rumex/chemistry , Silver/chemistry , Furans/chemistry , Green Chemistry Technology , Humans , Leukocytes, Mononuclear , Metal Nanoparticles/ultrastructure , Microbial Sensitivity Tests , Microbial Viability/drug effects , Particle Size , Plant Roots/chemistry , Surface Properties , THP-1 CellsABSTRACT
We have synthesized silver nanoparticles from silver nitrate solutions using extracts of Rumex hymenosepalus, a plant widely found in a large region in North America, as reducing agent. This plant is known to be rich in antioxidant molecules which we use as reducing agents. Silver nanoparticles grow in a single-step method, at room temperature, and with no addition of external energy. The nanoparticles have been characterized by ultraviolet-visible spectroscopy and transmission electron microscopy, as a function of the ratio of silver ions to reducing agent molecules. The nanoparticle diameters are in the range of 2 to 40 nm. High-resolution transmission electron microscopy and fast Fourier transform analysis show that two kinds of crystal structures are obtained: face-centered cubic and hexagonal.
ABSTRACT
Se evaluó la diversidad serológica y genética de cepas de Salmonella spp. aislada de campos de cultivo de melón Cantaloupe (Cucumis melo) y cilantro (Coriandrum sativum). Para identificar al patógeno se realizaron pruebas bioquímicas, serología, susceptibilidad a antibióticos y caracterización por PFGE. Se encontraron 11 muestras contaminadas de los campos de cilantro y 7 de los de melón. Se aisló Salmonella anatum y S. give, principalmente. Solo una de las cepas presentó resistencia a tobramicina. El PFGE mostró que cepas del mismo serogrupo, produjeron patrones electroforéticos similares y el análisis polifásico desplegó cinco grupos distintos con similitud menor al 35%. Es necesario intensificar las buenas prácticas agrícolas y de producción, ya que los serogrupos identificados han sido involucrados en brotes epidémicos. Por otro lado, el análisis polifásico mostró variabilidad genómica y además permite suponer que las cepas de S. give son clonales, no así para S. anatum, que estuvo presente en diferentes muestras.
The serological and genetic diversity of Salmonella spp. strains isolated from Cantaloupe melon (Cucumis melo) and coriander (Coriandrum sativum) fields were evaluated. Biochemical test, serology, antibiotic resistance and PFGE were performed to identify isolated strains. Eleven contaminated samples from coriander fields were found, and seven from melon fields. The serogroups identified were mainly Salmonella anatum and S. give. Only one strain was resistant to tobramicyn. PFGE showed five electrophoretic profiles, in agreement with the identified serotypes and in the polyphasic analysis five clusters were observed (<35% similarity). It is necessary to implement good agricultural and production practices, since identified serogroups have been involved in epidemic outbreaks. Moreover, the polyphasic analysis showed genomic variability and also suggests that strains of S. give are clonal. It is not the same for S. anatum strains, which were isolated from different samples.
Avaliou-se a diversidade sorológica e genética de cepas de Salmonella spp. isolada de campos de cultivo de melão Cantalupo (Cucumis melo) e coentro (Coriandrum sativum). Para identificar ao patógeno foram realizadas provas bioquímicas, sorologia, suscetibilidade a antibióticos e caracterização por PFGE. Encontraram-se 11 amostras contaminadas dos campos de coentro e 7 dos de melão. Isolou-se Salmonella anatum e S. give, principalmente. Somente uma das cepas apresentou resistência à tobramicina. O PFGE mostrou que cepas do mesmo sorogrupo, produziram padrões eletroforéticos similares e a análise polifásica desprendeu cinco grupos distintos com similitude menor a 35%. É necessário intensificar as boas práticas agrícolas e de produção, já que os sorogrupos identificados têm sido envolvidos em surtos epidêmicos. Por outro lado, a análise polifásica mostrou variabilidade genômica e além disso permite supor que as cepas de S. give são clonais, não sendo assim para S. anatum, que esteve presente em diferentes amostras.
