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In both developed and developing countries, atmospheric pollution with particulate matter (PM) remains an important issue. Despite the health effects of poor air quality, studies on air pollution are often limited by the high costs of continuous monitoring and the need for extensive sampling. Furthermore, these particles are often enriched with potentially toxic trace elements and organic pollutants. This study evaluates both the composition of atmospheric dust accumulated during a certain timespan on Hedera helix and Senecio cineraria leaves and the potential for their use as bio-monitors. The test plants were positioned near automatic air quality monitoring stations at four different sites with respectively high, moderate and low traffic intensity. The gravimetric deposition of PM10 and PM2.5 on leaves was compared with data recorded by the monitoring stations and related to the weather conditions reported by Argentina's National Meteorological Service. To determine the presence of trace elements enriching the PM deposited on leaves, two analytical techniques were applied: XRF (not destructive) and ICP (destructive). The results indicated that only in the unpaved street location (site 2) did PM10 and PM2.5 concentrations (90 µg m-3 and 9 µg m-3) in the air exceed more than five times WHO guidelines (15 µg m-3 and 5 µg m-3). However, several trace elements were found to be enriching PM deposited on leaves from all sites. Predominantly, increased concentrations of Cd, Cu, Ti, Mn, Zn and Fe were found, which were associated with construction, traffic and unpaved street sources. Furthermore, based on its capability to sequester above 2800 µg cm-2 of PM10, 2450 µg cm-2 of PM2.5 and trace elements, Senecio cineraria can be taken into consideration for adoption as a bio-monitor or even for PM mitigation.

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Trace elements pollution of soils became a global concern because of their persistence in the environment which can lead to accumulation in food chains up to toxic levels. At the same time, there is a shortage of arable land for growing food, fodder and industrial crops, which highlights the need for remediation/use of polluted land. Restoration of degraded lands has been included as a vital component of UN Sustainable Development Goals (SDGs). We summarize various sources of entry of important trace elements in the environment, available biological reclamation and management strategies and their limitations. Recent advances in phytomanagement approaches using aromatic crops to obtain economically valuable products such as essential oils and revalorize such polluted areas are reviewed. The worldwide application of this strategy in the last 10 years is illustrated through a choropleth map. Finally, the emerging concept of phytomanagement as a restorative and regenerative circular bio-economy is also discussed.

Phytomanagement studies have remarkably increased during the last 4 years. However, there were limited studies on field application of this strategy. France is the leading country in phytomanaged polluted fields using aromatic plants. Applying aromatic plants based degraded land management models are a sustainable approach toward circular economy and to achieve the objectives of sustainable development goals (SDGs).

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This field study aimed to assess the baseline conditions of a long-term shooting range in Argentina polluted with 428 mg kg-1 lead (Pb) to evaluate the establishment and development of Helianthus petiolaris plants and address the efficacy of the phytomanagement strategy through: (i) element accumulation in plant tissues; (ii) rhizosphere bacterial diversity changes by Illumina Miseq™, and (iii) floral water and essential oil yield, composition, and element concentration by GC-MS and ICP. After one life cycle growing in the polluted sites, in the roots of Helianthus petiolaris plants, Pb concentration was between 195 and 304 mg kg-1 Pb. Only a limited fraction of the Pb was translocated to the aerial parts. The predominance of the genus Serratia in the rhizosphere of Helianthus petiolaris plants cultivated in the polluted sites and the decrease in the essential oil yield were some effects significantly associated with soil Pb concentration. No detectable Pb concentration was found in the floral water and essential oil obtained. Extractable Pb concentration in the soil reduced between 28% and 45% after the harvest.

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Resumen Las estrategias en seguridad alimentaria con cultivos de alto contenido nutricionaldeben enmarcarse en prácticas agrícolas sostenibles, orientadas a la conservación del suelo, elalto rendimiento y la inocuidad. Esta última característica implica la producción de alimentos sintrazas detectables de agroquímicos, los que podrían amenazar la salud del consumidor. Se des-arrolló un estudio con el objetivo de evaluar el efecto del herbicida glifosato sobre la fertilidadquímica y microbiológica del suelo, así como su residualidad en la semilla de frijol biofortificadocultivado en el departamento de Cesar, Colombia. La metodología comprendió un análisis corre-lacional de indicadores de calidad de suelo, rendimiento del cultivo y residualidad en los granos.Los tratamientos evaluados incluyeron la aplicación o no de glifosato, el uso de coberturas sin-téticas (mulch) o naturales, frente al control manual de las malezas. Se hallaron diferenciasde rendimiento y de la respuesta de los indicadores químicos y microbiológicos en función deltratamiento y las condiciones iniciales de la rizósfera de frijol. La aplicación del herbicida glifo-sato en suelo sin mulch generó una disminución del 29% en el rendimiento, asociada a la mayorprevalencia de plagas y enfermedades fúngicas. En ninguno de los tratamientos con aplicaciónde glifosato se observó residualidad de este herbicida en semillas, pero sí de otras moléculasderivadas de insecticidas usados en el sistema local de producción. De este estudio se concluyóque en lotes de frijol biofortificado con alta presión de la maleza Cyperus rotundus (coquito), se recomienda el uso del herbicida glifosato acompañado de mulch como alternativa para mantener la productividad en el tiempo. Esto constituye un sistema de protección frente al efectonegativo del herbicida sobre ambos, el sistema radical de la planta y la microbiota del suelo.© 2019 Asociacion Argentina de Microbiologıa. Publicado por Elsevier España, S.L.U. Este es un artıculo Open Access bajo la licencia CC BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Abstract Strategies aimed at achieving food safety in crops of high nutritional value shouldbe carried out through sustainable agricultural practices aimed at soil conservation, high yieldand food safety. This latter characteristic implies food production without detectable tracesof agrochemicals that threaten health. The objective of this study was to assess the effect ofthe herbicide glyphosate on the chemical and biological fertility of the soil and to determineits residual activity on biofortified bean seeds in Codazzi, Department of Cesar, Colombia. Themethod included a correlational analysis of soil quality, crop yield and residuality in bean grains.The treatments included glyphosate application and synthetic and natural mulches, comparedto manual control. The results showed differences in the response of chemical, microbiologicaland yield indicators between treatments and the initial conditions of the bean rhizosphere. Theuse of the herbicide glyphosate in mulch-free soil generates yield losses of 29% associated witha higher incidence of pests and fungal diseases; in all treatments, no glyphosate residualitywas detected in seeds; however, residuality was detected in other molecules derived frominsecticides associated with the local production system. In conclusion, in plots with high weedpressure by Cyperus rotundus, the use of mulch is recommended as an alternative to maintainbean productivity over time; by offering protection against the effect of the herbicide on boththe root system of the plant and the soil microbiota of the biofortified bean crop.© 2019 Asociaci´on Argentina de Microbiolog´ıa. Published by Elsevier España, S.L.U. This is anopen access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/).

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Strategies aimed at achieving food safety in crops of high nutritional value should be carried out through sustainable agricultural practices aimed at soil conservation, high yield and food safety. This latter characteristic implies food production without detectable traces of agrochemicals that threaten health. The objective of this study was to assess the effect of the herbicide glyphosate on the chemical and biological fertility of the soil and to determine its residual activity on biofortified bean seeds in Codazzi, Department of Cesar, Colombia. The method included a correlational analysis of soil quality, crop yield and residuality in bean grains. The treatments included glyphosate application and synthetic and natural mulches, compared to manual control. The results showed differences in the response of chemical, microbiological and yield indicators between treatments and the initial conditions of the bean rhizosphere. The use of the herbicide glyphosate in mulch-free soil generates yield losses of 29% associated with a higher incidence of pests and fungal diseases; in all treatments, no glyphosate residuality was detected in seeds; however, residuality was detected in other molecules derived from insecticides associated with the local production system. In conclusion, in plots with high weed pressure by Cyperus rotundus, the use of mulch is recommended as an alternative to maintain bean productivity over time; by offering protection against the effect of the herbicide on both the root system of the plant and the soil microbiota of the biofortified bean crop.

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The large-scale use of the herbicide glyphosate leads to growing ecotoxicological and human health concerns. Microbe-assisted phytoremediation arises as a good option to remove, contain, or degrade glyphosate from soils and waterbodies, and thus avoid further spreading to non-target areas. To achieve this, availability of plant-colonizing, glyphosate-tolerant and -degrading strains is required and at the same time, it must be linked to plant-microorganism interaction studies focusing on a substantive ability to colonize the roots and degrade or transform the herbicide. In this work, we isolated bacteria from a chronically glyphosate-exposed site in Argentina, evaluated their glyphosate tolerance using the minimum inhibitory concentration assay, their in vitro degradation potential, their plant growth-promotion traits, and performed whole genome sequencing to gain insight into the application of a phytoremediation strategy to remediate glyphosate contaminated agronomic soils. Twenty-four soil and root-associated bacterial strains were isolated. Sixteen could grow using glyphosate as the sole source of phosphorous. As shown in MIC assay, some strains tolerated up to 10000 mg kg-1 of glyphosate. Most of them also demonstrated a diverse spectrum of in vitro plant growth-promotion traits, confirmed in their genome sequences. Two representative isolates were studied for their root colonization. An isolate of Ochrobactrum haematophilum exhibited different colonization patterns in the rhizoplane compared to an isolate of Rhizobium sp. Both strains were able to metabolize almost 50% of the original glyphosate concentration of 50 mg l-1 in 9 days. In a microcosms experiment with Lotus corniculatus L, O. haematophilum performed better than Rhizobium, with 97% of glyphosate transformed after 20 days. The results suggest that L. corniculatus in combination with to O. haematophilum can be adopted for phytoremediation of glyphosate on agricultural soils. An effective strategy is presented of linking the experimental data from the isolation of tolerant bacteria with performing plant-bacteria interaction tests to demonstrate positive effects on the removal of glyphosate from soils.

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We report here on a high-quality draft genome sequence of Ochrobactrum haematophilum strain P6BS-III (DSM 106071), a Gram negative, non-sporulating bacterium isolated from a pastureland (Buenos Aires province, Argentina) which had been chronically exposed to the herbicide glyphosate. The genome of 5.25 Mb with a DNA G+C content of 56.63% size was estimated to contain 5,291 protein coding genes and 57 RNA genes. Genome analysis revealed the presence of the phn operon, which is involved in the phosphonate degradation pathway, and a class II 5-enolpyruvylshikimate-3-phosphate synthase (EPSP) that confers tolerance to glyphosate. Genes related to plant growth promotion traits are also present, and include genes for phosphorus metabolism, calcium phosphate and phytate solubilization, siderophore production, organic acid biosynthesis and indole acetic acid (IAA) production.

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Resumen La caries dental, es una patología de origen multifactorial y actualmente los productos naturales son un tratamiento alternativo eficiente. El trabajo buscó evaluar la actividad antimicrobiana del aceite esencial de tres sustancias (Cymbopogon citratus y los componentes citral y mirceno) contra Streptococcus mutans ATCC UA159, así como su citotoxicidad sobre queratinocitos y fibroblastos humanos. A través de Microscopía Electrónica de Barrido, se observó la morfología típica de S. mutans, y una formación característica de polisacáridos, con una disposición más estructurada a las 48 h. El efecto de viabilidad bacteriana contra S. mutans en biofilms se evaluó a través de la exposición a las tres sustancias mediante el uso de la técnica de alto rendimiento MBEC, a concentraciones de 1, 0.1 y 0.01 μg/ml y clorhexidina como control positivo. La citotoxicidad de los compuestos se evaluó sobre queratinocitos y fibroblastos, mediante la técnica de reducción de MTT, utilizando 0.5 mM de H2O2 como control de muerte celular (control negativo) y etanol 1 % como control del vehículo (control positivo). Las tres sustancias evaluadas, tuvieron efectos sobre la viabilidad bacteriana de S. mutans con una mortalidad entre 74 y 96 %, sin diferencia significativa entre ellos (P > 0.393); adicionalmente, no fue evidente la citotoxicidad sobre queratinocitos y fibroblastos en un tratamiento de 24 h. Las sustancias evaluadas mostraron efectos antimicrobianos significativos; por lo tanto, estos deben estudiarse más a fondo como posibles coadyuvantes para prevenir la caries dental que causa efectos adversos menores.(AU)

Abstract Dental caries is a pathology of multifactorial origin and currently natural products are an efficient alternative treatment. The work sought to evaluate the antimicrobial activity of the three substances (Cymbopogon citratus essential oil and the citral and myrcene components) against Streptococcus mutans ATCC UA159, as well as their cytotoxicity on keratinocytes and human fibroblasts. Through Scanning electron microscopy, the typical morphology of S. mutans was observed and, a characteristic formation of polysaccharides, with more structured arrangement at 48 h. The bacterial viability effect against S. mutans on biofilms was evaluated through exposure to the three substances by using the MBEC technique-high-throughput at concentrations of 1, 0.1, and 0.01 µg/mL and chlorhexidine as positive control. The cytotoxicity of the compounds was evaluated on keratinocytes and fibroblasts through the MTT reduction technique, using 0.5 mM H2O2 as cell-death control (negative control) and ethanol 1 % as vehicle control (positive control). The three substances evaluated had effects on the bacterial viability of S. mutans with mortality between 74 and 96 %, without significant difference among them (P > 0.393); additionally, no cytotoxicity was evident on keratinocytes and fibroblasts in a 24 h treatment. The substances evaluated showed significant antimicrobial effects; hence, these should be studied further as potential co-adjuvants to prevent dental caries that cause minor adverse effects.(AU)

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A bacterial consortium able to degrade the herbicide 4-(2,4-dichlorophenoxy) butyric acid (2,4-DB) was obtained from an agricultural soil of the Argentinean Humid Pampa region which has a history of long-term herbicide use. Four bacterial strains were isolated from the consortium and identified as members of the genera Cupriavidus, Labrys and Pseudomonas. A polyphasic systematic analysis was carried out on strain CPDB6(T), the member of the 2,4-DB-degrading consortium able to degrade 2,4-DB as a sole carbon and energy source. The Gram-negative, rod-shaped, motile, non-sporulating, non-fermenting bacterium was shown to belong to the genus Cupriavidus on the basis of 16S rRNA gene sequence analyses. Strain CPDB6(T) did not reduce nitrate, which differentiated it from the type species of the genus, Cupriavidus necator; it did not grow in 0.5-4.5 % NaCl, although most species of Cupriavidus are able to grow at NaCl concentrations as high as 1.5 %; and it was able to deamidate acetamide, which differentiated it from all other species of Cupriavidus. DNA-DNA hybridization data revealed low levels of genomic DNA similarity (less than 30 %) between strain CPDB6(T) and the type strains of Cupriavidus species with validly published names. The major cellular fatty acids detected were cis-9-hexadecenoic (16 : 1ω7c) and hexadecanoic (16 : 0) acids. On the basis of phenotypic and genotypic characterizations, strain CPDB6(T) was recognized as a representative of a novel species within the genus Cupriavidus. The name Cupriavidus pampae sp. nov. is proposed, with strain CPDB6(T) (=CCUG 55948(T)=CCM-A-29:1289(T)) as the type strain.

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Atrazine impact on human health and the environment have been extensively studied. Phytoremediation emerged as a low cost, environmental friendly biotechnological solution for atrazine pollution in soil and water. In vitro atrazine tolerance assays were performed and Lolium multiflorum was found as a novel tolerant species, able to germinate and grow in the presence of 1 mg kg(-1) of the herbicide. L. multiflorum presented 20% higher atrazine removal capacity than the natural attenuation, with high initial degradation rate in microcosms. The mechanisms involved in atrazine tolerance such as mutation in psbA gene, enzymatic detoxification via P(450) or chemical hydrolysis through benzoxazinones were evaluated. It was demonstrated that atrazine tolerance is conferred by enhanced enzymatic detoxification via P(450). Due to its atrazine degradation capacity in soil and its agronomical properties, L. multiflorum is a candidate for designing phytoremediation strategies for atrazine contaminated agricultural soils, especially those involving run-off avoiding.

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The 2,4-dichlorophenoxyacetic acid (2,4-D) is a hormone-like herbicide widely used in agriculture. Although its half life in soil is approximately two weeks, the thousands of tons introduced in the environment every year represent a risk for human health and the environment. Considering the toxic properties of this compound and its degradation products, it is important to assess and monitor the 2,4-D residues in agricultural soils. Furthermore, experiments of phyto/bioremediation are carried out to find economic and environmental friendly tools to restore the polluted soils. Accordingly, it is essential to accurately measure the amount of 2,4-D and its metabolites in soils. There is evidence that 2,4-D extraction from soil samples seriously depends on the physical and chemical properties of the soil, especially in those soils with high content of humic acids. The aim of this work was to assess the variables that influence the recovery and subsequent analysis of 2,4-D and its main metabolite (2,4-dichlorophenol) from those soils samples. The results showed that the recovery efficiency depends on the solvent and method used for the extraction, the amount and kind of solvent used for dissolving the herbicide and the soil water content at the moment of spiking. An optimized protocol for the extraction and quantification of 2,4-D and its main metabolite from soil samples is presented.

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The dissipation of 4-(2,4-dichlorophenoxy) butyric acid (2,4-DB) in high-humic-matter-containing soils from agricultural fields of the Argentinean Humid Pampa region was studied, employing soil microcosms under different experimental conditions. The added herbicide was dissipated almost completely by soils with and without history of herbicide use by day 28. At 500 ppm, both soils showed the same degradation rates; but at 5-ppm concentration, the chronically exposed soil demonstrated a faster degradation of the herbicide. 2,4-DB addition produced increases in herbicide-degrading bacteria of three and 1.5 orders of magnitude in soils with and without history of herbicide use, respectively, in microcosms with 5 ppm. At 500-ppm concentration, the increase in 2,4-DB degraders was five orders of magnitude after 14 days, independent of the history of herbicide use. No differences were observed in either 2,4-DB degradation rates or in degrader bacteria numbers in the presence and absence of alfalfa plants, in spite of some differential characteristics in patterns of 2,4-DB metabolite accumulation. The main factor affecting 2,4-DB degradation rate would be the history of herbicide use, as a consequence of the adaptation of the indigenous microflora to the presence of herbicides in the field.

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Phenoxy herbicides like 2,4-dichlorophenoxyacetic acid (2,4-D) are widely used in agricultural practices. Although its half life in soil is 7-14d, the herbicide itself and its first metabolite 2,4-dichlorophenol (2,4-DCP) could remain in the soil for longer periods, as a consequence of its intensive use. Microcosms assays were conducted to study the influence of indigenous microflora and plants (alfalfa) on the dissipation of 2,4-D from soils of the Humid Pampa region, Argentina, with previous history of phenoxy herbicides application. Results showed that 2,4-D was rapidly degraded, and the permanence of 2,4-DCP in soil depended on the presence of plants and soil microorganisms. Regarding soil microbial community, the presence of 2,4-D degrading bacteria was detected even in basal conditions in this soil, possibly due to the adaptation of the microflora to the herbicide. There was an increment of two orders of magnitude in herbicide degraders after 15d from 2,4-D addition, both in planted and unplanted microcosms. Total heterotrophic bacteria numbers were about 1x10(8) CFUg(-1) dry soil and no significant differences were found between different treatments. Overall, the information provided by this work indicates that the soil under study has an important intrinsic degradation capacity, given by a microbial community adapted to the presence of phenoxy herbicides.

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