1,005 research outputs found

    Global Antifungal Profile Optimization of Chlorophenyl Derivatives against Botrytis cinerea and Colletotrichum gloeosporioides

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    Twenty-two aromatic derivatives bearing a chlorine atom and a different chain in the para or meta position were prepared and evaluated for their in vitro antifungal activity against the phytopathogenic fungi Botrytis cinerea and Colletotrichum gloeosporioides. The results showed that maximum inhibition of the growth of these fungi was exhibited for enantiomers S and R of 1-(40-chlorophenyl)- 2-phenylethanol (3 and 4). Furthermore, their antifungal activity showed a clear structure-activity relationship (SAR) trend confirming the importance of the benzyl hydroxyl group in the inhibitory mechanism of the compounds studied. Additionally, a multiobjective optimization study of the global antifungal profile of chlorophenyl derivatives was conducted in order to establish a rational strategy for the filtering of new fungicide candidates from combinatorial libraries. The MOOPDESIRE methodology was used for this purpose providing reliable ranking models that can be used later

    Biogeochemistry of carbon in the Amazonian Floodplains over a 2000-km reach: insights from a process-based model.

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    The influence of Amazonian floodplains on the hydrological, sedimentary, and biogeochemical river budget was investigated over a 2000-km reach. A process-based model relying on the closure of chemical fluxes and isotopic signals was implemented. On average for the whole studied reach, the overall fluxes of carbon associated with mineralization and aquatic photosynthesis were estimated to 35.7 and 15.3 Tg C yr21, respectively. Almost 57% of the carbon sequestrated by photosynthesis comes from aerial sources (flooded forest); the remaining 43% resulted from aquatic sources (va´rzea grasses and phytoplankton). The process rates substantially fluctuate over the annual cycle, depending particularly on the extension of flooded area and on the river?floodplain connectivity. As the river level declines, the drastic decrease of turbidity and the lower supply of carbon substrates promote autotrophy to the detriment of heterotrophy, leading to substantial changes of pH and gaseous equilibria in the river water. The main consequences are (i) the side-chain oxidation of dissolved organic matter leading to the concomitant rises of the carbon to nitrogen atomic ratio and nitrate contents and (ii) the sorption of hydrophobic humic acids, which fractionate 13C and thus lead to 13C-depleted particulate organic matter (fine fraction) compared to remaining dissolved organic matter. As the river flow rises, the heterotrophy prevails over autotrophy and this tends to attenuate the chemical signature imprinted by the latter. The significant contribution of aerial autochthonous sources to the budget of carbon indicates that the fluxes of mineralization are sustained by the net primary production of river corridors. The variable extension of submerged areas defines the proportions of CO2 exported by the river and released to the atmosphere. The rate of CO2 outgassing on the studied reach (18.8 Tg C yr21) represents about 50% of the incoming dissolved inorganic carbon flux. The rate of methane emission is estimated as 2.2 Tg C yr21 and that of denitrification is estimated as 0.87 Tg N yr21, representing 1.5 times the flux of dissolved inorganic nitrogen (DIN) exported by the Amazon River at the station of O ´ bidos (0.64 Tg N yr21)

    Biological control of the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae) by Phymastichus coffea (Hymenoptera: Eulophidae) in Colombia

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    The potential of the eulophid parasitoid Phymastichus coffea LaSalle to control coffee berry borer Hypothenemus hampei (Ferrari) populations under field conditions in Colombia was evaluated. Parasitoid adults were released one, five and nine days after artificial infestations of 90-, 150- and 210-day-old coffee berries with H. hampei females. The position of the beetle inside the berry and the parasitism levels were assessed ten days after each P. coffea release. Parasitism of H. hampei by P. coffea was significantly affected by the age of the berries at the time of infestation, and by the position of the beetle inside the berries. Highest levels of parasitism were recorded in 150-day-old berries (75-85%) and in 90-day-old berries (75%) when P. coffea were released one day after the artificial infestation with H. hampei. In 150-day-old berries, highest levels of parasitism were recorded for H. hampei found in the outer layer of the endosperm followed by beetles penetrating the exocarp. Increasing the time of P. coffea releases after the artificial infestations with H. hampei led to decreased levels of parasitism in beetles attacking 90- and 150-day-old coffee berries. Low levels of parasitism were recorded in H. hampei females infesting older coffee berries because most of the beetles had already constructed galleries deep in the endosperm of the berries, i.e. out of reach of the parasitoid. The potential of P. coffea for biological control of coffee berry borer in Colombia is discussed. © CAB International, 2005

    Electroconvulsive Therapy Response in Major Depressive Disorder: a Pilot Functional Network Connectivity Resting State FMRI Investigation

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    Major depressive disorder (MDD) is associated with increased functional connectivity in specific neural networks. Electroconvulsive therapy (ECT), the gold-standard treat- ment for acute, treatment-resistant MDD, but temporal dependencies between networks associated with ECT response have yet to be investigated. In the present longitudinal, case–control investigation, we used independent component analysis to identify distinct networks of brain regions with temporally coherent hemodynamic signal change and func- tional network connectivity (FNC) to assess component time course correlations across these networks. MDD subjects completed imaging and clinical assessments immediately prior to the ECT series and a minimum of 5 days after the last ECT treatment. We focused our analysis on four networks affected in MDD: the subcallosal cingulate gyrus, default mode, dorsal lateral prefrontal cortex, and dorsal medial prefrontal cortex (DMPFC). In an older sample of ECT subjects (n = 12) with MDD, remission associated with the ECT series reverses the relationship from negative to positive between the posterior default mode (p_DM) and two other networks: the DMPFC and left dorsal lateral prefrontal cortex (l_DLPFC). Relative to demographically healthy subjects (n = 12), the FNC between the p_DM areas and the DMPFC normalizes with ECT response. The FNC changes following treatment did not correlate with symptom improvement; however, a direct comparison between ECT remitters and non-remitters showed the pattern of increased FNC between the p_DM and l_DLPFC following ECT to be specific to those who responded to the treat- ment.The differences between ECT remitters and non-remitters suggest that this increased FNC between p_DM areas and the left dorsolateral prefrontal cortex is a neural correlate and potential biomarker of recovery from a depressed episode

    Comparative assessment of satellite- and drone-based vegetation indices to predict arthropod biomass in shrub-steppes

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    Arthropod biomass is a key element in ecosystem functionality and a basic food item for many species. It must be estimated through traditional costly field sampling, normally at just a few sampling points. Arthropod biomass and plant productivity should be narrowly related because a large majority of arthropods are herbivorous, and others depend on these. Quantifying plant productivity with satellite or aerial vehicle imagery is an easy and fast procedure already tested and implemented in agriculture and field ecology. However, the capability of satellite or aerial vehicle imagery for quantifying arthropod biomass and its relationship with plant productivity has been scarcely addressed. Here, we used unmanned aerial vehicle (UAV) and satellite Sentinel-2 (S2) imagery to establish a relationship between plant productivity and arthropod biomass estimated through ground-truth field sampling in shrub steppes. We UAV-sampled seven plots of 47.6–72.3 ha at a 4-cm pixel resolution, subsequently downscaling spatial resolution to 50 cm resolution. In parallel, we used S2 imagery from the same and other dates and locations at 10-m spatial resolution. We related several vegetation indices (VIs) with arthropod biomass (epigeous, coprophagous, and four functional consumer groups: predatory, detritivore, phytophagous, and diverse) estimated at 41–48 sampling stations for UAV flying plots and in 67–79 sampling stations for S2. VIs derived from UAV were consistently and positively related to all arthropod biomass groups. Three out of seven and six out of seven S2-derived VIs were positively related to epigeous and coprophagous arthropod biomass, respectively. The blue normalized difference VI (BNDVI) and enhanced normalized difference VI (ENDVI) showed consistent and positive relationships with arthropod biomass, regardless of the arthropod group or spatial resolution. Our results showed that UAV and S2-VI imagery data may be viable and cost-efficient alternatives for quantifying arthropod biomass at large scales in shrub steppes. The relationship between VI and arthropod biomass is probably habitat-dependent, so future research should address this relationship and include several habitats to validate VIs as proxies of arthropod biomassBBVA Foundation, BBVA Dron Ricoti project; European Commission, Grant/ Award Number: LIFE15-NAT-ES-000802; REMEDINAL-3 from CAM; European Comission, Grant/Award Number: LIFE20-NAT-ES-00013
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