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14. Solar UV-B radiation and ethylene play a key role in modulating effective defenses against Anticarsia gemmatalis larvae in field-grown soybean

Author

Dillon, Francisco María, Tejedor, María Daniela, Ilina, Natalia, Chludil, Hugo Daniel, Mithöfer, Axel, Pagano, Eduardo Antonio, and Zavala, Jorge Alberto

Subjects
CIENCIAS AGRÍCOLAS, PLANT-INSECT INTERACTIONS, fungi, JASMONIC ACID, food and beverages, Otras Ciencias Agrícolas, SALICYLIC ACID
Abstract

Solar UV-B radiation has been reported to enhance plant defenses against herbivore insects in many species. However, the mechanism and traits involved in the UV-B mediated increment of plant resistance are unknown in crops species, such as soybean. Here, we studied defense-related responses in undamaged and Anticarsia gemmatalis larvae-damaged leaves of two soybean cultivars grown under attenuated or full solar UV-B radiation. We determined changes in jasmonates, ethylene (ET), salicylic acid, trypsin protease inhibitor activity, flavonoids, and mRNA expression of genes related with defenses. ET emission induced by Anticarsia gemmatalis damage was synergistically increased in plants grown under solar UV-B radiation and was positively correlated with malonyl genistin concentration, trypsin proteinase inhibitor activity and expression of IFS2, and the pathogenesis protein PR2, while was negatively correlated with leaf consumption. The precursor of ET, aminocyclopropane-carboxylic acid, applied exogenously to soybean was sufficient to strongly induce leaf isoflavonoids. Our results showed that in field-grown soybean isoflavonoids were regulated by both herbivory and solar UV-B inducible ET, whereas flavonols were regulated by solar UV-B radiation only and not by herbivory or ET. Our study suggests that, although ET can modulate UV-B-mediated priming of inducible plant defenses, some plant defenses, such as isoflavonoids, are regulated by ET alone. Fil: Dillon, Francisco María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Tejedor, María Daniela. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Ilina, Natalia. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Chludil, Hugo Daniel. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Mithöfer, Axel. Instituto Max Planck Institut für Chemische Okologie; Alemania Fil: Pagano, Eduardo Antonio. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Zavala, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina

Published
2018

15. Aceites esenciales de naranja

Author

Corbino, Graciela Beatriz, Chludil, Hugo Daniel, García De Leo, Gonzalo, Regge, María Belén, and Arroyo, Luis Enrique

Subjects
Citrus, Naranja Dulce, Yields, Rendimiento, Sweet Oranges, Essential Oils, Chemical Composition, Frutas Cítricas, Aceites Esenciales, Piel (vegetal), Composición Quimica, Peel, San Pedro, Buenos Aires, Citrus Fruits
Abstract

El trabajo aborda el análisis del rendimiento y la composición química de los aceites esenciales de la piel de variedades de naranja dulce. La producción de fruta cítrica en Argentina es de aproximadamente 3.100.000 toneladas (2016), de las cuales 1.000.000 corresponde a naranjas. Estas tienen como principal destino el consumo en el mercado interno y un bajo porcentaje se destina a la industria. Argentina es uno de los principales países exportadores de aceite esencial de limón. Si bien esto representa un bajo porcentaje del total de las exportaciones, debería considerarse como un producto de la oferta exportable con gran potencial de desarrollo. Los aceites esenciales son mezclas de compuestos lipofílicos y se clasifican en terpenos hidrocarbonados, compuestos oxigenados y compuestos no volátiles. Los aceites esenciales obtenidos de los cítricos son reconocidos como seguros (GRAS) por la FDA, de modo que pueden ser utilizados en la industria de los alimentos (saborizantes, recubrimientos comestibles), cosméticos y farmacéutica. Poseen actividad antioxidante y antimicrobiana. El objetivo del presente trabajo fue obtener el rendimiento y analizar los perfiles de terpenos presentes en el flabelo de variedades de naranja (Citrus sp.) dulce, cultivadas en San Pedro, con el propósito de buscar usos alternativos. Los frutos de naranja fueron recolectados de plantas pertenecientes a lotes experimentales del INTA San Pedro. Se analizaron 6 variedades (New Hall, Robertson, Navelina, Fiorito, Parent y Porta). El aceite esencial (AE) de la piel (200-300 g PF) se obtuvo por hidrodestilación, usando una trampa Clevenger. El aceite recolectado luego de 1 h de destilación se lo secó con Na2SO4 y se almacenó a -18 oC. Las extracciones se realizaron por cuadruplicado. Se calculó el rendimiento y se realizó el análisis cromatográfico (CG-EM) de los AE obtenidos utilizando un cromatógrafo Agilent Tech 7890A, con detector 5977A MSD y una columna Hp5 ms (Agilent Tech). Los datos se sometieron a un análisis de variancia (ANOVA). Los mayores rendimientos se obtuvieron de la variedad New Hall, seguido de Robertson y Navelina. Las variedades de naranja analizadas poseen principalmente monoterpenos hidrocarbonados (C10) de los cuales el D-limoneno fue el mayoritario, hallándose entre un 80-89%, seguido por el β-pineno (3.5-4.2%) y α-pineno (0.9-1.2 %) y en menor proporción monoterpenos oxigenados. Entre los elementos traza, considerados con un rol importante en la determinación del olor y sabor, se observaron diferencias significativas en el contenido de aldehídos alifáticos (octanal, nonanal y decanal), presentando Navelina y Porta los valores más contrastantes, 4,53 y 1,26 %, respectivamente. La obtención del aceite podría proponerse una alternativa tradicional, pero poco explotada comercialmente, al aprovechamiento del descarte de la fruta. EEA San Pedro Fil: Corbino, Graciela Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; Argentina Fil: Chludil, Hugo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos; Argentina Fil: García De Leo, Gonzalo. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Regge, María Belén. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Arroyo, Luis Enrique. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; Argentina

Published
2018

17. Long‐term legacy of land‐use change in soils from a subtropical rainforest: Relating microbiological and physicochemical parameters.

Author

Tosi, Micaela, Chludil, Hugo D., Correa, Olga S., Vogrig, Jimena A., and Montecchia, Marcela S.

Subjects
*SOIL microbial ecology, *RAIN forests, *SOILS, *MICROBIAL communities, *SOIL composition, *LAND use, *FATTY acids
Abstract

Tropical and subtropical ecosystems are widely affected by the expansion of agriculture over pristine lands. Despite research efforts, knowledge of the impact of land‐use change on soil is still limited by intrinsic variability, inconsistent results and inadequate replication. This study aimed to better understand the consequences of land‐use change by focusing on long‐term effects on both soil biotic and abiotic parameters. For this purpose, we selected three productive farms under similar management, each of them with pristine forest sites and agricultural sites that had been deforested for ~15 and ~30 years. In each site, we analysed soil microbiological (phospholipid fatty acids [PLFAs], biomass and activity) and physicochemical parameters. Long‐term land‐use change caused a detriment in soil microbial biomass, activity and fungal abundance, but only small changes in PLFA composition. In fact, PLFA composition was more affected by soil physicochemical properties such as carbon‐to‐nutrient ratios and labile carbon than by land use. Some physicochemical parameters (e.g., organic carbon and nutrients) were also negatively affected by land‐use change and were more sensitive to time under agricultural use than microbiological parameters. The lower sensitivity of microbiological parameters could be the result of severe drought conditions at sampling, which may have affected soil microbial communities in both land uses. We were also able to detect associations between specific microbiological and physicochemical parameters. Among these, we identified some that seemed to result from their co‐variation in response to land‐use change and others that seemed to be independent of land use. Overall, our results show that soils can suffer further deterioration several years after deforestation. In order to restore soil health in these degraded lands, we need to keep on investigating the physical, chemical and biological mechanisms responsible for this deterioration. Highlights: Land‐use change affected soil microbiological and physicochemical parameters.Microbiological parameters seemed to stabilize after continuous agriculture.Soil organic C, total N and fine particles were still reduced after long‐term cultivation.Microbiological parameters were mostly associated with C‐to‐nutrient ratios and labile C.Drought conditions may have affected microbial response to land‐use change. [ABSTRACT FROM AUTHOR]

Published
2021
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19. Soybean resistance to stink bugs (Nezara viridula and Piezodorus guildinii) increases with exposure to solar UV-B radiation and correlates with isoflavonoid content in pods under field conditions

Author

Zavala, Jorge Alberto, Mazza, Carlos Alberto, Dillon, Francisco María, Chludil, Hugo Daniel, and Ballare, Carlos Luis

Subjects
Ciencias Biológicas, purl.org/becyt/ford/1 [https], Flavonoid, Plant Defense, purl.org/becyt/ford/1.6 [https], Insect, Ciencias de las Plantas, Botánica, CIENCIAS NATURALES Y EXACTAS
Abstract

Solar UV-B radiation (280–315 nm) has a significant influence on trophic relationships in natural and managed ecosystems, affecting plant–insect interactions. We explored the effects of ambient UV-B radiation on the levels of herbivory by stink bugs (Nezara viridula and Piezodorus guildinii) in field-grown soybean crops. The experiments included two levels of UV-B radiation (ambient and attenuated UV-B) and four soybean cultivars known to differ in their content of soluble leaf phenolics. Ambient UV-B radiation increased the accumulation of the isoflavonoids daidzin and genistin in the pods of all cultivars. Soybean crops grown under attenuated UV-B had higher numbers of unfilled pods and damaged seeds than crops grown under ambient UV-B radiation. Binary choice experiments with soybean branches demonstrated that stink bugs preferred branches of the attenuated UV-B treatment. We found a positive correlation between percentage of undamaged seeds and the contents of daidzin and genistin in pods. Our results suggest that constitutive and UV-B-induced isoflavonoids increase plant resistance to stink bugs under field conditions. Fil: Zavala, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Pque. Centenario. Instituto de Investigaciones En Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomia. Instituto de Investigaciones En Biociencias Agrícolas y Ambientales; Argentina Fil: Mazza, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina Fil: Dillon, Francisco María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Pque. Centenario. Instituto de Investigaciones En Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomia. Instituto de Investigaciones En Biociencias Agrícolas y Ambientales; Argentina Fil: Chludil, Hugo Daniel. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Biología Aplicada y Alimentos. Cátedra de Química de Biomoleculas; Argentina Fil: Ballare, Carlos Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martin. Instituto de Investigaciones Biotecnologicas; Argentina

Published
2015

21. Host selection, oviposition behaviour and leaf traits in a specialist willow sawfly on species of Salix (Salicaceae)

Author

Braccini, Celina L., Vega, Andrea Susana, Chludil, Hugo Daniel, Leicach, Silvia Rosa, and Fernandez, Patricia Carina

Subjects
Ciencias Biológicas, OVIPOSITION PREFERENCE, MICROMORPHOLOGY, Zoología, Ornitología, Entomología, Etología, CIENCIAS NATURALES Y EXACTAS, GENOTYPE, NEMATUS OLIGOSPILUS
Abstract

1. Plant genotype influences plant-herbivore interactions by affecting insect attraction, acceptance and development. Here we linked oviposition behaviour of the specialist willow sawfly Nematus oligospilus F¨orster (Hymenoptera: Tenthredinidae) with leaf traits on different Salix L. (Salicaceae) genotypes. This was done as a first step to find oviposition cues that guide females to their host plants. 2. By means of choice and no-choice bioassays we analysed host selection according to willow genotype and leaf surface. We also studied larval performance, adult fecundity and effect of experience on host selection. Nematus oligospilus prefers to oviposit on S. nigra L. The least preferred genotype, S. viminalis, showed better larval performance and highest adult fecundity. Host preference was not modified by larval feeding experience. 3. By means of light and scanning electron microscopy we described ovipositor and leaf micromorphology. The egg is laid inside the epidermis or between the epidermis and adjacent chlorenchyma, showing a tight association with the leaf. Leaf toughness was lowest for S. nigra and higher for S. viminalis and S. babylonica. Total nitrogen and protein content were higher on S. viminalis and S. babylonica. Total phenolics and phenolic glycosides were the highest and more diverse on S. nigra. Salicin content levels correlate with oviposition preference, suggesting the role of salicylates as oviposition stimulants. 4. Results suggest that oviposition preference on S. nigra may be related to lower leaf toughness and ease of injection of female saw-like ovipositor, and motivated by the presence of phenolic glycosides. Nitrogen levels may explain better larval performance and adult fecundity in S. viminalis. Thus, a balance among the different leaf traits determines the outcomes observed in this study. Fil: Braccini, Celina L.. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; Argentina Fil: Vega, Andrea Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Chludil, Hugo Daniel. Universidad de Buenos Aires. Facultad de Agronomia; Argentina Fil: Leicach, Silvia Rosa. Universidad de Buenos Aires. Facultad de Agronomia; Argentina Fil: Fernandez, Patricia Carina. Universidad de Buenos Aires. Facultad de Agronomia; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Norte. Estación Experimental Agropecuaria Delta del Paraná; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Published
2013

22. Solar UV‐B radiation and ethylene play a key role in modulating effective defenses against Anticarsia gemmatalis larvae in field‐grown soybean.

Author

Dillon, Francisco M., Tejedor, M. Daniela, Ilina, Natalia, Chludil, Hugo D., Mithöfer, Axel, Pagano, Eduardo A., and Zavala, Jorge A.

Subjects
SOLAR ultraviolet radiation, PLANT defenses, HERBIVORES, SOYBEAN, ETHYLENE, VELVET-bean caterpillar
Abstract

Abstract: Solar UV‐B radiation has been reported to enhance plant defenses against herbivore insects in many species. However, the mechanism and traits involved in the UV‐B mediated increment of plant resistance are unknown in crops species, such as soybean. Here, we studied defense‐related responses in undamaged and Anticarsia gemmatalis larvae‐damaged leaves of two soybean cultivars grown under attenuated or full solar UV‐B radiation. We determined changes in jasmonates, ethylene (ET), salicylic acid, trypsin protease inhibitor activity, flavonoids, and mRNA expression of genes related with defenses. ET emission induced by Anticarsia gemmatalis damage was synergistically increased in plants grown under solar UV‐B radiation and was positively correlated with malonyl genistin concentration, trypsin proteinase inhibitor activity and expression of IFS2, and the pathogenesis protein PR2, while was negatively correlated with leaf consumption. The precursor of ET, aminocyclopropane‐carboxylic acid, applied exogenously to soybean was sufficient to strongly induce leaf isoflavonoids. Our results showed that in field‐grown soybean isoflavonoids were regulated by both herbivory and solar UV‐B inducible ET, whereas flavonols were regulated by solar UV‐B radiation only and not by herbivory or ET. Our study suggests that, although ET can modulate UV‐B‐mediated priming of inducible plant defenses, some plant defenses, such as isoflavonoids, are regulated by ET alone. [ABSTRACT FROM AUTHOR]

Published
2018
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28. Soybean resistance to stink bugs ( N ezara viridula and P iezodorus guildinii) increases with exposure to solar UV- B radiation and correlates with isoflavonoid content in pods under field conditions.

Author

ZAVALA, JORGE A., MAZZA, CARLOS A., DILLON, FRANCISCO M., CHLUDIL, HUGO D., and BALLARÉ, CARLOS L.

Subjects
SOLAR ultraviolet radiation, SOYBEAN, PLANT resistance to insects, STINKBUGS, ISOFLAVONOIDS, PLANT ecology, INSECT-plant relationships
Abstract

Solar UV- B radiation (280-315 nm) has a significant influence on trophic relationships in natural and managed ecosystems, affecting plant-insect interactions. We explored the effects of ambient UV- B radiation on the levels of herbivory by stink bugs ( N ezara viridula and P iezodorus guildinii) in field-grown soybean crops. The experiments included two levels of UV- B radiation (ambient and attenuated UV- B) and four soybean cultivars known to differ in their content of soluble leaf phenolics. Ambient UV- B radiation increased the accumulation of the isoflavonoids daidzin and genistin in the pods of all cultivars. Soybean crops grown under attenuated UV- B had higher numbers of unfilled pods and damaged seeds than crops grown under ambient UV- B radiation. Binary choice experiments with soybean branches demonstrated that stink bugs preferred branches of the attenuated UV- B treatment. We found a positive correlation between percentage of undamaged seeds and the contents of daidzin and genistin in pods. Our results suggest that constitutive and UV- B-induced isoflavonoids increase plant resistance to stink bugs under field conditions. [ABSTRACT FROM AUTHOR]

Published
2015
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34. Relación entre la emisión de señales volátiles de las mezclas de Artemisia annua - soja, Chenopodium album - soja sobre la herbivoría de Anticarsia gemmatalis y sus enemigos naturales

Author

Torcat Fuentes, Marianne, De la Fuente, Elba Beatriz, Chludil, Hugo Daniel, and Zavala, Jorge Alberto

Subjects
COMPETENCIA BIOLOGICA, CRECIMIENTO COMPENSADOR, BIODIVERSIDAD, ANTICARSIA GEMMATALIS, ENEMIGOS NATURALES, MALEZAS, ARTEMISIA ANNUA, CHENOPODIUM
Abstract

La expansión del cultivo de soja (Glycine max L.) en el agroecosistema pampeano estuvo asociada a la pérdida de la diversidad de cultivos y de especies silvestres. Una alternativa para revertir esta situación, es el desarrollo de estrategias de manejo que diversifiquen el sistema productivo. Para ello es importante identificar las especies candidatas, y conocer su comportamiento en mezclas con los demás componentes del agroecosistema. El objetivo general de la tesis fue evaluar el crecimiento, la producción de compuestos de defensa y la emisión de señales del cultivo de soja puro o en mezclas con Artemisia annua y Chenopodium album y su relación con la herbivoría y supervivencia del lepidóptero Anticarsia gemmatalis y la comunidad de insectos asociada. En condiciones semi-controladas durante cuatro campañas consecutivas, se realizaron experimentos factoriales con tres repeticiones. Los factores fueron, cinco niveles de densidad: soja pura, soja + 2 y 4 plantas de A. annua/m2 y soja + 2 y 4 plantas de C. album/m2 y dos niveles de herbivoría de A. gemmatalis: con y sin herbívoros. La herbivoría se logró introduciendo 100 orugas de A. gemmatalis. Los resultados mostraron que la herbivoría sobre el cultivo fue significativamente menor cuando estuvo en mezclas. La presencia de malezas no ocasionó pérdidas del rendimiento del cultivo, gracias a su capacidad compensatoria. La presencia de A. annua dentro de la mezcla promovió la producción de determinados -blends? de compuestos de defensa en soja. Las señales químicas generadas por las distintas mezclas estuvieron asociadas a distintas comunidades de insectos. La riqueza de insectos en general y de no herbívoros en particular, fue mayor cuando el cultivo estuvo en mezclas. Los resultados de esta tesis brindan nuevos aportes al conocimiento de las interacciones tróficas dentro de un agroecosistema y nuevos elementos para el diseño de estrategias de manejo más sustentables.

Published
2020

35. Aspectos estructurales y funcionales de las comunidades microbianas del suelo en una cronosecuencia de uso agrícola del pedemonte de Yungas

Author

Tosi, Micaela, Correa, Olga Susana, Montecchia, Marcela Susana, and Chludil, Hugo Daniel

Subjects
ECOLOGIA MICROBIANA, BIOLOGIA DEL SUELO, ESTABILIDAD, DESMONTE, REGION DEL NOROESTE, ESTRES DE SEQUIA, YUNGAS, BIOMASA
Abstract

Las Yungas del noroeste argentino han sido fuertemente afectadas por el desmonte de tierras prístinas, en particular de pedemonte, para el cultivo extensivo. El objetivo de esta tesis fue estudiar, a través de una cronosecuencia, el efecto del desmonte y el tiempo bajo uso agrícola sobre las comunidades microbianas del suelo (CMS) en una zona productiva de la región. El muestreo se realizó sobre tres fincas como réplicas independientes de cada categoría de uso: 0, 3-5, 11-14 y 28-30 años de cultivo. Se evaluaron aspectos estructurales y funcionales de las CMS, así como su resistencia y resiliencia al estrés hídrico. Luego de 3-5 años de cultivo se destacó una reducción en biomasa microbiana y funciones hidrolíticas (fosfatasa ácida y amonificación), y un incremento en respiración basal y cociente metabólico qCO2 (i.e., menor eficiencia metabólica). Asimismo, con PCR cuantitativo se detectó una reducción en la abundancia de metanótrofos totales y de tipo II. La mayoría de las variables se estabilizaron (biomasa, actividad hidrolítica) o restablecieron parcialmente (respiración, qCO2) a lo largo de la cronosecuencia. En respuesta al estrés hídrico impuesto, las CMS de larga historia agrícola presentaron la mayor resistencia y resiliencia en biomasa, estructura de ácidos grasos de los fosfolípidos y eficiencia metabólica. Por su parte, las CMS de monte de destacaron por su resiliencia en estos aspectos y mayor resistencia en la utilización de un sustrato recalcitrante, mientras que las de corta historia agrícola se mostraron en general más frágiles y variables. Los resultados sugieren que las CMS se alteran marcadamente con posterioridad al desmonte, en respuesta a cambios en la cobertura vegetal y a las labores ligadas a esta transición, en tanto que sucesivos años bajo el mismo manejo agrícola parecen inducir una homogeneización de las CMS junto con una adaptación a las condiciones impuestas por la agricultura.

Published
2017

36. Assessing South American Guadua chacoensis bamboo biochar and Fe 3 O 4 nanoparticle dispersed analogues for aqueous arsenic(V) remediation.

Author

Alchouron J, Navarathna C, Chludil HD, Dewage NB, Perez F, Hassan EB, Pittman CU Jr, Vega AS, and Mlsna TE

Subjects
Adsorption, Arsenic, Charcoal, Ferric Compounds, Kinetics, Metal Nanoparticles, Water Pollutants, Chemical, Sasa, Water Purification
Abstract

Discarded bamboo culms of Guadua chacoensis were used for biochar remediation of aqueous As(V). Raw biochar (BC), activated biochar (BCA), raw Fe 3 O 4 nanoparticle-covered biochar (BC-Fe), and activated biochar covered with Fe 3 O 4 nanoparticles (BCA-Fe) were prepared, characterized and tested for As(V) aqueous adsorption. The goal is to develop an economic, viable, and sustainable adsorbent to provide safe arsenic-free water. Adsorbents were characterized using scanning electron microscopy (SEM) and energy dispersive analysis by X-ray (SEM-EDX), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (TEM-EDS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), Brunauer-Emmett-Teller surface area measurements (S BET ), point of zero charge determinations (PZC), and elemental analysis. Activation with KOH increased the O/C ratio and the surface area of BC from 6.7 m 2 /g to 1239.7 m 2 /g (BCA). As(V) sorption equilibrium was achieved within <2 h for all four adsorbents and kinetics followed the pseudo-second-order model. At a 10 mg/L initial As(V) concentration, BC-Fe achieved a 100% removal (5 mg/g) over a pH 5 to 9 window. Sorption was endothermic on all four adsorbents and the capacities rose with the increasing temperature. Langmuir capacities at 40 °C for BC, BCA, BC-Fe, and BCA-Fe were 256, 217, 457, and 868 mg/g, respectively, and capacities were compared with other sorbents. Breakthrough fixed-bed column sorption was carried out for BC and BC-Fe producing 6.6 mg/g and 13.9 mg/g bed capacities, respectively. Potassium phosphate was a better As stripping agent than sodium bicarbonate. Performance of the adsorbents in an As(V)-spiked natural water and a naturally As(V)-contaminated domestic water were assessed. Robust arsenate sequestration occurred generating As-safe water (As <0.01 mg/L), despite the presence of competing ions. Stoichiometric precipitation of iron-arsenate complexes triggered by iron dissolution was also established., (Copyright © 2019. Published by Elsevier B.V.)

Published
2020
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37. Soybean resistance to stink bugs (Nezara viridula and Piezodorus guildinii) increases with exposure to solar UV-B radiation and correlates with isoflavonoid content in pods under field conditions.

Author

Zavala JA, Mazza CA, Dillon FM, Chludil HD, and Ballaré CL

Subjects
Animals, Fruit metabolism, Glycine max metabolism, Ultraviolet Rays, Genistein metabolism, Herbivory, Heteroptera, Isoflavones metabolism, Glycine max radiation effects
Abstract

Solar UV-B radiation (280-315 nm) has a significant influence on trophic relationships in natural and managed ecosystems, affecting plant-insect interactions. We explored the effects of ambient UV-B radiation on the levels of herbivory by stink bugs (Nezara viridula and Piezodorus guildinii) in field-grown soybean crops. The experiments included two levels of UV-B radiation (ambient and attenuated UV-B) and four soybean cultivars known to differ in their content of soluble leaf phenolics. Ambient UV-B radiation increased the accumulation of the isoflavonoids daidzin and genistin in the pods of all cultivars. Soybean crops grown under attenuated UV-B had higher numbers of unfilled pods and damaged seeds than crops grown under ambient UV-B radiation. Binary choice experiments with soybean branches demonstrated that stink bugs preferred branches of the attenuated UV-B treatment. We found a positive correlation between percentage of undamaged seeds and the contents of daidzin and genistin in pods. Our results suggest that constitutive and UV-B-induced isoflavonoids increase plant resistance to stink bugs under field conditions., (© 2014 John Wiley & Sons Ltd.)

Published
2015
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38. Antifungal steroidal glycosides from the patagonian starfish anasteriasminuta: structure-activity correlations.

Author

Chludil HD, Seldes AM, and Maier MS

Subjects
Animals, Antifungal Agents chemistry, Antifungal Agents pharmacology, Argentina, Cholestenones chemistry, Cholestenones pharmacology, Chromatography, High Pressure Liquid, Chromatography, Thin Layer, Dose-Response Relationship, Drug, Glycosides chemistry, Glycosides pharmacology, Molecular Structure, Nuclear Magnetic Resonance, Biomolecular, Pregnenes chemistry, Pregnenes pharmacology, Structure-Activity Relationship, Antifungal Agents isolation & purification, Cholestenones isolation & purification, Cladosporium drug effects, Glycosides isolation & purification, Pregnenes isolation & purification, Starfish chemistry
Abstract

Two new sulfated steroidal hexaglycosides, anasterosides A (2) and B (3), along with the known versicoside A (1) have been isolated from the Patagonian starfish Anasterias minuta. Their structures have been elucidated by spectroscopic analysis (NMR and FABMS) and chemical transformations. Compounds 1 and 2 and the synthetic pentaglycoside 1b derived from versicoside A showed antifungal activity against the plant pathogenic fungus Cladosporium cucumerinum. Desulfation of hexaglycoside 1 rendered a totally inactive saponin.

Published
2002
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