Prospecting intercropping between subterranean clover and grapevine as potential strategy for improving grapevine performance

Abstract Intercropping is an agricultural practice commonly used to improve plant nutrition. In this study, we prospected the interaction between root exudates of subterranean clover (Trifolium subterraneum L.) and grapevine (Vitis vinifera L.). This experiment was focused on the detection of organic acids, amino acids, and flavonoids in root exudates released by grapevine and subterranean clover grown separately and together. Furthermore, we quantified low-molecular-weight organic acids (LMWOA) in root exudates. To test the effect of root exudates in plant-plant chemical signaling, both species were grown in Hoagland hydroponic solution. The experimental design contained three treatments: T1 (subterranean clover, monocropping); T2 (grapevine, monocropping) and T3 (subterranean clover + grapevine, intercropping). The exudate profile showed that the main compounds were amino acid, flavonoids and organic acids in all treatments. Specifically, amino acids exudates (∼20%) were l -threonine by subterranean clover in monocropping (T1) and glutathione in intercropping with grapevine (T3). Glycylglycine was detected in exudates released by subterranean clover (T1) and both plants under intercropping (T3). Regarding flavonoids (∼10%), epicatechin was detected only in subterranean clover exudates (T1). Interestingly, we detected kaempferol-3-glucuronide, l -2-aminoadipic and gluconic acids were found only under intercropping. The LMWOA were oxalic, malic, citric, and succinic. Oxalic acid was released in higher concentration. We highlight that succinic acid reached the highest concentration under intercropping on day-30. These results strongly suggest that amino acids, flavonoids and organic acids acts as signaling compounds between plant-plant interaction, can be utilized for improving grapevine plant performance

Effects on informal learning of biological evolution as results of museum mediation

Los museos interactivos de ciencia se han considerado como espacios donde puede ocurrir el aprendizaje informal de las ciencias, sobre todo cuando la comunicación es facilitada entre los equipos exhibidos y el visitante. Se presenta aquí una investigación que busca definir los efectos sobre la adquisición de conocimientos, resolución de problemas y actitudes frente a la ciencia en las visitas mediadas a una exposición acerca de un tema de difícil comunicación y comprensión como es el de la evolución biológica. Se encuentra que las ganancias en los dos primeros aspectos no son significativamente diferentes cuando las visitas son guiadas, pero la presencia de los guías ayuda a resolver dudas y genera el deseo de regresar al museo. El guía es apoyo invaluable para recuperar recuerdos e información previa a la visita, además de que reduce notoriamente la escasa aceptación por el tema y centra la atención en el tema principal de la exposición. Pero el efecto más importante de la presencia de un guía es que ayuda a cumplir las expectativas de la visita de tener acceso a información de calidad, clara, precisa y lúdica. El deseo de que la experiencia dure más tiempo, habla de que la visita guiada puede incrementar el tiempo de permanencia en la sala. Estos últimos hallazgos requieren ser considerados en la capacitación de los guías y en la planeación de las visitas a museos interactivos de ciencia por parte de los profesores.Interactive science museums have been considered spaces where informal learning can occur especially when the communication between exhibits and visitors is facilitated. A research is presented here, in which the effects on knowledge, problem solving and attitudes towards science in mediated visits to an exhibition about biological evolution (which tends to be a communicative difficult theme) are evaluated. The results show that there is no significant gaining between the two first aspects in the case of guided visits, but instead, the presence of museum guides helps to solve questions and promotes the desire to visit again. So, the guides are an invaluable support to explore visitor’s previous information and to reduce the dislike for a particular topic. Besides, it enhances the attention on the main subject of the exhibition and helps to fulfill the expectances of the visit. All this promotes the desire to have a longer visit, which can increase the time spent in the museum. These findings will have to be taken into account in the guide’s preparation

Efectos sobre el aprendizaje informal de la evolución biológica como resultado de la mediación museal

Interactive science museums have been considered spaces where informal learning can occur especially when the communication between exhibits and visitors is facilitated. A research is presented here, in which the effects on knowledge, problem solving and attitudes towards science in mediated visits to an exhibition about biological evolution (which tends to be a communicative difficult theme) are evaluated. The results show that there is no significant gaining between the two first aspects in the case of guided visits, but instead, the presence of museum guides helps to solve questions and promotes the desire to visit again. So, the guides are an invaluable support to explore visitor’s previous information and to reduce the dislike for a particular topic. Besides, it enhances the attention on the main subject of the exhibition and helps to fulfill the expectances of the visit. All this promotes the desire to have a longer visit, which can increase the time spent in the museum. These findings will have to be taken into account in the guide’s preparation.Los museos interactivos de ciencia se han considerado como espacios donde puede ocurrir el aprendizaje informal de las ciencias, sobre todo cuando la comunicación es facilitada entre los equipos exhibidos y el visitante. Se presenta aquí una investigación que busca definir los efectos sobre la adquisición de conocimientos, resolución de problemas y actitudes frente a la ciencia en las visitas mediadas a una exposición acerca de un tema de difícil comunicación y comprensión como es el de la evolución biológica. Se encuentra que las ganancias en los dos primeros aspectos no son significativamente diferentes cuando las visitas son guiadas, pero la presencia de los guías ayuda a resolver dudas y genera el deseo de regresar al museo. El guía es apoyo invaluable para recuperar recuerdos e información previa a la visita, además de que reduce notoriamente la escasa aceptación por el tema y centra la atención en el tema principal de la exposición. Pero el efecto más importante de la presencia de un guía es que ayuda a cumplir las expectativas de la visita de tener acceso a información de calidad, clara, precisa y lúdica. El deseo de que la experiencia dure más tiempo, habla de que la visita guiada puede incrementar el tiempo de permanencia en la sala. Estos últimos hallazgos requieren ser considerados en la capacitación de los guías y en la planeación de las visitas a museos interactivos de ciencia por parte de los profesores.Palabras clave: aprendizaje informal; mediación; museos interactivos; evolución biológica; profesorado.Effects on informal learning of biological evolution as results of museum mediationInteractive science museums have been considered spaces where informal learning can occur especially when the communication between exhibits and visitors is facilitated. A research is presented here, in which the effects on knowledge, problem solving and attitudes towards science in mediated visits to an exhibition about biological evolution (which tends to be a communicative difficult theme) are evaluated. The results show that there is no significant gaining between the two first aspects in the case of guided visits, but instead, the presence of museum guides helps to solve questions and promotes the desire to visit again. So, the guides are an invaluable support to explore visitor’s previous information and to reduce the dislike for a particular topic. Besides, it enhances the attention on the main subject of the exhibition and helps to fulfill the expectances of the visit. All this promotes the desire to have a longer visit, which can increase the time spent in the museum. These findings will have to be taken into account in the guide’s preparation.Keywords: informal learning; mediation; interactive museums; biological evolution; teachers

Understanding the strategies to overcome phosphorus-deficiency and aluminum toxicity by ryegrass endophytic and rhizosphere phosphobacteria

Phosphobacteria, secreting organic acids and phosphatases, usually favor plant performance in acidic soils by increasing phosphorus (P) availability and aluminum (Al) complexing. However, it is not well-known how P-deficiency and Al-toxicity affect the phosphobacteria physiology. Since P and Al problems often co-occur in acidic soils, we have therefore proposed the evaluation of the single and combined effects of P-deficiency and Al-toxicity on growth, organic acids secretion, malate dehydrogenase (mdh) gene expression, and phosphatase activity of five Al-tolerant phosphobacteria previously isolated from ryegrass. These phosphobacteria were identified as Klebsiella sp. RC3, Stenotrophomona sp. RC5, Klebsiella sp. RCJ4, Serratia sp. RCJ6, and Enterobacter sp. RJAL6. The strains were cultivated in mineral media modified to obtain (i) high P in absence of Al-toxicity, (ii) high P in presence of Al-toxicity, (iii) low P in absence of Al-toxicity, and (iv) low P in presence of Al-toxicity. High and low P were obtained by adding KH2PO4 at final concentration of 1.4 and 0.05 mM, respectively. To avoid Al precipitation, AlCl3 × 6H2O was previously complexed to citric acid (sole carbon source) in concentrations of 10 mM. The secreted organic acids were identified and quantified by HPLC, relative mdh gene expression was determined by qRT-PCR and phosphatase activity was colorimetrically determined using p-nitrophenyl phosphate as substrate. Our results revealed that although a higher secretion of all organic acids was achieved under P-deficiency, the patterns of organic acids secretion were variable and dependent on treatment and strain. The organic acid secretion is exacerbated when Al was added into media, particularly in the form of malic and citric acid. The mdh gene expression was significantly up-regulated by the strains RC3, RC5, and RCJ6 under P-deficiency and Al-toxicity. In general, Al-tolerant phosphobacteria under P deficiency increased both acid and alkaline phosphatase activity with respect to the control, which was deepened when Al was present. The knowledge of this bacterial behavior in vitro is important to understand and predict the behavior of phosphobacteria in vivo. This knowledge is essential to generate smart and efficient biofertilizers, based in Al-tolerant phosphobacteria which could be expansively used in acidic soil

Endophytic selenobacteria and arbuscular mycorrhizal fungus for Selenium biofortification and Gaeumannomyces graminis biocontrol

Selenium (Se) is an important antioxidant considered among the fertilization programs in developed countries. In Chile, chemical fertilization based in Se is inefficient due the physicochemical characteristics of Andisol that sustain the 60% of crop production. Andisol also are highly conductive to take-all disease caused by Gaeumannonyces graminis var tritici (Ggt). Here, we evaluated the effect of Bacillus sp.E5 and Acinetobacter sp.E6.2 and Claroideoglomus claroideum as potential inocula for Se biofortification and Ggt bicontrol in wheat. Plants inoculated with Acinetobacter sp.E6.2 showed major root growth and major Se content in shoots and grains. The antioxidant role of Se regarding DPPH activity was shown in Se-supplemented plants with small Se nanoparticles founded inside the roots. Mycorrhizal plants showed major SOD activity in shoots but no affected the Se uptake. Respect to pathogen biocontrol, plants inoculated with both bacteria showed an efficient control against Ggt independent to mycorrhization. Thus, our inocula could make important contributions to produce enriched Se flours for human nutrition and biocontrol against Ggt

Efficient and selective removal of SeVI and AsV mixed contaminants from aqueous media by montmorillonite-nanoscale zero valent iron nanocomposite

Nanoscale zero-valent iron (NZVI) and NZVI supported onto montmorillonite (NZVI-Mt) were synthetized and used in this study to remove SeVI and AsV from water in mono- and binary-adsorbate systems. The adsorption kinetics and isotherm data for SeVI and AsV were adequately described by the pseudo-second-order (PSO) (r2>0.94) and Freundlich (r2>0.93) equations. Results from scanning electron microscopy showed that the dimension of the NZVI immobilized on the Mt was smaller than pure NZVI. Using 0.05 g of adsorbent and an initial 200 mg L−1 AsV and SeVI concentration, the maximum adsorption capacity (qmax) and partition coefficient (PC) for AsV on NZVI-Mt in monocomponent system were 54.75 mg g-1 and 0.065 mg g-1·μM-1, which dropped respectively to 49.91 mg g-1 and 0.055 mg g-1·μM-1 under competitive system. For SeVI adsorption on NZVI-Mt in monocomponent system, qmax and PC were 28.63 mg g-1 and 0.024 mg g-1·μM-1, respectively. Values of qmax and PC were higher for NZVI-Mt than NZVI and montmorillonite, indicating that the nanocomposite contained greater adsorption sites for removing both oxyanions, but with a marked preference for AsV. Future research should evaluate the effect of different operational variables on the removal efficiency of both oxyanions by NZVI-Mt

Microbial Community Composition in Take-All Suppressive Soils

Gaeumannomyces graminis var. tritici (Ggt) is the main soilborne factor that affects wheat production around the world. Recently we reported the occurrence of six suppressive soils in monoculture areas from indigenous "Mapuche" communities, and evidenced that the suppression relied on the biotic component of those soils. Here, we compare the rhizosphere and endosphere microbial community structure (total bacteria, actinomycetes, total fungi, and ascomycetes) of wheat plants grown in suppressive and conducive soils. Our results suggested that Ggt suppression could be mediated mostly by bacterial endophytes, rather than rhizosphere microorganisms, since the community structure was similar in all suppressive soils as compared with conducive. Interestingly, we found that despite the lower incidence of take-all disease in suppressive soils, the Ggt concentration in roots was not significantly reduced in all suppressive soils compared to those growing in conducive soil. Therefore, the disease suppression is not always related to a reduction of the pathogen biomass. Furthermore, we isolated endophytic bacteria from wheat roots growing in suppressive soils. Among them we identified Serratia spp. and Enterobacter spp. able to inhibit Ggt growth in vitro. Since the disease, but not always pathogen amount, was reduced in the suppressive soils, we propose that take all disease suppressiveness is not only related to direct antagonism to the pathoge

Screening for K13-Propeller Mutations Associated with Artemisinin Resistance in Plasmodium falciparum in Yambio County (Western Equatoria State, South Sudan)

Artemisinin-combined treatments are the recommended first-line treatment of Plasmodium falciparum malaria, but they are being threatened by emerging artemisinin resistance. Mutations in pfk13 are the principal molecular marker for artemisinin resistance. This study characterizes the presence of mutations in pfk13 in P. falciparum in Western Equatoria State, South Sudan. We analyzed 468 samples from patients with symptomatic malaria and found 15 mutations (8 nonsynonymous and 7 synonymous). Each mutation appeared only once, and none were validated or candidate markers of artemisinin resistance. However, some mutations were in the same or following position of validated and candidate resistance markers, suggesting instability of the gene that could lead to resistance. The R561L nonsynonymous mutation was found in the same position as the R561H validated mutation. Moreover, the A578S mutation, which is widespread in Africa, was also reported in this study. We found a high diversity of other pfk13 mutations in low frequency. Therefore, routine molecular surveillance of resistance markers is highly recommended to promptly detect the emergence of resistance-related mutations and to limit their spread.Financial support: The intervention was funded by Medecins Sans Frontieres, and samples were analyzed through a research agreement between Medecins Sans Frontieres and the National Centre of Tropical Medicine/Institute of Health Carlos III, Agreement No: TRVP 121/20. I. M. F. received a research fellowship (FPU-2019) from the University of Alcala, Spain, that enabled her to conduct this study.S

Investigación clinicoepidemiológica en envejecimiento: metodología del proyecto encuesta salud, bienestar y envejecimiento (SABE) en México

La población de personas adultas mayores crece de forma paulatina y sostenida en el mundo y por ende en nuestro país. Sin embargo, la información que se tiene sobre la forma de vida, salud y bienestar de este grupo poblacional es limitada debido a que la mayor parte de las investigaciones en adultos mayores es derivada del estudio de grupos pequeños con patología bien circunscrita y características especiales. Por otro lado, la realización de estudios, en la población abierta, que permitan establecer la demografía y epidemiología de las personas mayores de 60 años requieren de una gran infraestructura y recursos tanto humanos como económicos. El Proyecto-Encuesta Salud Bienestar y Envejecimiento (SABE), mediante la realización de un estudio tipo encuesta, tiene la finalidad de obtener dicha información contando conla participación del Sector Salud, instituciones de educación superior así como organizaciones no gubernamentales lo que constituye un logro interinstitucional. Para la realización del proyecto SABE se ha seguido con rigurosidad científica el protocolo y para su puesta en marcha hubo la necesidad de la integración intersectorial de las instituciones que brindan atención a los adultos mayores mexicanos, ya sea dentro del contexto de la seguridad o asistencia social. Los alcances de SABE permitirán la creación y difusión del conocimiento derivado del mismo. En este documento, se expone y analiza de forma breve y concreta la metodología operativa de SABE México, lo que significa dar el primer paso para que otros investigadores interesados en el tema, realicen este tipo de estudios. Dada la experiencia que se ha ido generando en la realización de SABE México, este tipo de documentos sirven como base para proponer e iniciar las acciones al respecto.&nbsp