The continuous introduction of cleaning products containing benzalkonium chloride (BAC) from household discharges can mold the microbial communities in wastewater treatment plants (WWTPs) in a way still poorly understood. In this study, we performed an in vitro exposure of activated sludge from a WWTP in Costa Rica to BAC, quantified the changes in intI1, sul2, and qacE/qacEΔ1 gene profiles, and determined alterations in the bacterial community composition. The analysis of the qPCR data revealed elevated charges of antibiotic resistance genes in the microbial community; after BAC's exposure, a significant increase in the qacE/qacEΔ1 gene, which is related to ammonium quaternary resistance, was observed. The 16S rRNA gene sequences’ analysis showed pronounced variations in the structure of the bacterial communities, including reduction of the alpha diversity values and an increase of the relative abundance of Alphaproteobacteria, particularly of Rhodospseudomonas and Rhodobacter. We confirmed that the microbial communities presented high resilience to BAC at the mg/mL concentration, probably due to constant exposure to this pollutant. They also presented antibiotic resistance-related genes with similar mechanisms to tolerate this substance. These mechanisms should be explored more thoroughly, especially in the context of high use of disinfectant.

Abrin is a toxic protein produced by the ornamental plant Abrus precatorius, and it is of concern as a biothreat agent. The small coextracting molecule N-methyl-L-tryptophan (L-abrine) is specific to members of the genus Abrus and thus can be used as a marker for the presence or ingestion of abrin. Current methods for the detection of abrin or L-abrine in foods and other matrices require complex sample preparation and expensive instrumentation. To develop a fast and portable method for the detection of L-abrine in beverages and foods, the Escherichia coli proteins N-methyltryptophan oxidase (MTOX) and tryptophanase were expressed and purified. The two enzymes jointly degraded L-abrine to products that included ammonia and indole, and colorimetric assays for the detection of those analytes in beverage and food samples were evaluated. An indole assay using a modified version of Ehrlich's/Kovac's reagent was more sensitive and less subject to negative interferences from components in the samples than the Berthelot ammonia assay. The two enzymes were added into food and beverage samples spiked with L-abrine, and indole was detected as a degradation product, with the visual lower detection limit being 2.5 to 10.0 M (ϳ0.6 to 2.2 ppm) L-abrine in the samples tested. Results could be obtained in as little as 15 min. Sample preparation was limited to pH adjustment of some samples. Visual detection was found to be about as sensitive as detection with a spectrophotometer, especially in milkbased matrices. R ecent ricin poisoning attempts by individuals have validated concerns about the availability of highly toxic materials that are produced by widely cultivated plants (1). Ricin is isolated from seeds of the castor bean plant (Ricinus communis), which is grown ornamentally throughout the world and is cultivated in large scale for oil production, primarily in Asia and South America (2). The taxonomically unrelated legume Abrus precatorius, also known as China doll eyes, the rosary pea, or jequirity bean plant, produces the protein toxin abrin, which is similar to ricin in structure and mode of action (inactivation of ribosomes) and has a level of toxicity equal to or greater than that of ricin (3). Abrus precatorius is likely native to Southeast Asia but has been introduced as an ornamental plant to other tropical and subtropical areas around the world, where it has spread and naturalized (2). Its seeds have long been used as ornamental jewelry and toy doll eyes, and accidental poisonings have resulted from the ingestion of seeds used for those purposes (2, 3).Direct and indirect methods for the detection of abrin or ricin are typically based on immunoassays, mass spectrometry (MS), or PCR (2, 4, 5), all of which require sample preparation and/or specialized instrumentation. Indirect detection can be done by using PCR amplification of DNA targeted to the source plants or through liquid chromatography-MS identification of small molecules that coextract from plant material with the toxic proteins and therefore can serve as m...

El III Congreso en Economía Agrícola y Agronegocios (III CEAA) surge como un espacio de encuentro que pretende democratizar el conocimiento y las investigaciones ligadas al sector agropecuario, desde la perspectiva nacional e internacional, permeando de manera directa al sector público, privado, académico, estudiantil y sociedad civil. La Escuela de Economía Agrícola y Agronegocios (EEAA) y el Centro de Investigación en Economía Agrícola y Desarrollo Agroempresarial (CIEDA) en el marco de su 30 aniversario, organizaron para esta tercera edición del congreso, un espacio de intercambio académico-profesional y teórico-práctico en torno a los siguientes ejes temáticos: Economía agrícola y desarrollo rural: La relación que existe entre el sector agropecuario y sus interacciones con el sector de la economía, esto con el fin de mejorar la calidad de vida de las comunidades no urbanas. Desarrollo agroempresarial: El desarrollo de toda aquella empresa que se dedica a brindarle valor agregado a los bienes agrícolas, pecuarios o forestales para brindarle una mayor satisfacción al consumidor. Bioeconomía, sostenibilidad y cambio climático: La gestión sostenible de la productividad en donde se toma en cuenta factores ambientales y sociales con el fin de reducir el cambio climático. Es así, como en torno a los ejes anteriormente mencionados, fueron llevándose a cabo de ponencias, sesiones de poster, talleres de actualización profesional y visitas académicas, donde se contó con la participación de expertos y visitantes de Chile, Guatemala, México, Paraguay, Brasil y Francia. A nivel nacional, la delegación costarricense fue representada por exponentes de instituciones públicas (CINPE-UNA, BCCR, INDER, MAG) cuerpo docente de la EEAA, egresados y estudiantes de la Facultad de Ciencias Agroalimentarias. Autores y autoras:    Adolfo Castro Méndez Adrián González Estrada Albert Campos Arguello Alfredo Cesín Vargas América Patiño Delgado Ana Lilia Hernández Espinoza Ana Lucía Morales Abarca André Luiz Marqus Serrano Carlos Enrique González Blanco Carlos Rosano Peña Cristina Rodríguez Román Daniel Alpízar Rojas Daniel Romero Martínez Dennis Loría Paniagua Esteban Valtierra Pacheco Evaldo Cesar Cavalcante Rodrigues Fernando Cervantes Escoto Fernando López Alcocer Gerardo Cortés Muñoz Janet Fuentes Castillo Jorge Aguilar Ávila José David Barboza Navarro José Ignacio Sánchez Gómez José Márcio Carvalho Juan Arturo Ruiz Pereyra Juan Patricio Castro Ibañez Lorenzo Alejandro López Barboza Lorenzo Alejandro López Barboza Luis Felipe Arauz Cavallini Luis Miguel Barboza Arias Luz Elena Barrantes Aguilar María Castro Navarro María del Carmen Álvarez  Maritza Ferreira da Silva  Nancy Nazario Lezama Nathaly Montero Solís Norma Eugenia Sánchez García Octavio Tadeo Barrera Perales Patricia Cordero Cortés René Alejandro Ibarra Franco Roberto Lutz Porras Rodrigo Agüero Chacón Rodrigo Andrés Valdez Salazar Sergio Márquez Berber Siany Fabiola Guillén Castro Silvia Arguedas Villalobos Stella Mary Amarilla Rodríguez Valeria Mora Villalobos Vanessa Villalobos Ramos Víctor Rodríguez Lizano