1,052 research outputs found

    Managing phenology for agronomic adaptation of global cropping systems to climate change

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    Der Klimawandel fordert die Anbausysteme heraus, um das derzeitige Produktionsniveau zu verbessern oder sogar aufrechtzuerhalten. Es wird erwartet, dass zukünftige Trends bei Temperatur und Niederschlag die Ernteproduktivität beeinträchtigen. Es ist daher notwendig, möglicher Lösungen zur Anpassung der Anbausysteme an den Klimawandel zu untersuchen. Ziel dieser Arbeit ist es, das Wissen über die Anpassung von weltweit relevanten Getreidepflanzen an den Klimawandel zu erweitern. Die zentrale Fragestellung ist, ob globale Anbausysteme an den Klimawandel angepasst werden können, indem die Phänologie der Kulturpflanzen durch Anpassung von Wachstumsperioden und Sorten gesteuert wird. Die Phänologie und die Ertragsreaktionen sowohl auf den Temperaturanstieg als auch auf die Sortenselektion werden zunächst anhand eines Ensembles von “Global Gridded Crop Models” bewertet. Anschließend wird die Komplexität der Anpassung durch phänologisches Management analysiert, insbesondere unter Berücksichtigung der bestehenden großen Wissenslücken bei der Auswahl von Pflanzensorten. Das Ergebnis der Analyse ist ein regelbasierter Algorithmus, der phänologische Zyklen der Kulturpflanzen auswählt, um die Zeit für die Ertragsbildung zu maximieren und Temperatur- und Wasserbelastungen während der Wachstumszyklen der Kulturpflanzen zu minimieren. Die berechneten Aussaatdaten und Wachstumsperioden werden verwendet, um globale Muster von Sorten zu parametrisieren, die an aktuelle und zukünftige Klimaszenarien angepasst sind. Diese Arbeit zeigt, dass die Auswirkungen des Klimawandels auf die Pflanzenproduktivität erheblich variieren können, je nachdem, welche Annahmen für das agronomische Management getroffen werden. Änderungen im Management zu vernachlässigen, liefert die pessimistischste Prognose für die zukünftige Pflanzenproduktion. Relativ einfache Ansätze zur Berechnung angepasster Aussaatdaten und Sorten bieten eine Grundlage für die Berücksichtigung autonomer Anpassungsschemata als integraler Bestandteil globaler Modellierungsrahmen.Climate change is challenging cropping systems to enhance or even maintain current production levels. Future trends in temperature and precipitation are expected to negatively impact crop productivity. It is therefore necessary to explore adaptation options of cropping systems to changing climate. The aim of this thesis is to advance knowledge on adaptation of world-wide relevant grain crops to climate change. The central research question is whether global cropping systems can be adapted to climate change by managing crop phenology through adjusting growing periods and cultivars. Phenology and yield responses to both temperature increase and cultivar selection are first assessed making use of an ensemble of Global Gridded Crop Models. Then, the complexity of adaptation through phenological management is analysed, particularly addressing the existing large knowledge gaps on crop cultivar choice. The outcome of the analysis is a rule-based algorithm that selects crop phenological cycles aiming at maximizing the time for yield formation and minimizing temperature and water stresses during the crop growth cycles. The computed sowing dates and growing periods are used to parametrize global patterns of cultivars adapted to present and future climate scenarios. This thesis demonstrates that the impacts of climate change on crop productivity can vary substantially depending on which assumptions are made on agronomic management. Neglecting any changes in management return the most pessimistic projection on future crop production. Relatively simple approaches to compute adapted sowing dates and cultivars provide a base for considering autonomous adaptation schemes as an integral component of global scale modelling frameworks

    New records and geographic distribution map of Bothropoides diporus Cope, 1862 (Reptilia: Viperidae)

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    We provide two new records of Bothropoides diporus for Neuquén province, northern Patagonia, Argentina. Both records are the second and third for this species in this province. One of these records, from the northern slope of Auca Mahuida Mountain, extends approximately 120 km to the north the present known geographic distribution of this species in Neuquén province.Fil: Minoli, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Janis Alvarez, Diego. Universidade Federal do Rio Grande do Sul; BrasilFil: Avila, Luciano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

    Philodryas trilineata (Argentinean mousehole snake). Diet

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    Philodryas trilineata is a large (maximum length = 200 cm) species endemic to the Monte biogeographic region in western Argentina (Giraudo and Scrocchi 2002. Smithson. Herpetol. Inform. Serv. 132: 1-53). The diet of P. trilineata is known to include birds, mammals, lizards, and other snakes; some individuals are known to hunt domestic fowl or rabbits (Cei 1993. Reptiles del Noroeste, Nordeste y Este de la Argentina. Herpetofauna de las Selvas Subtropicales, Puna y Pampas. Mus. Reg. Sci. Nat. Torino. 945 pp.; Laspiur et al. 2012. Herpetol. Rev. 432151-152).Fil: Minoli, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Perez, Cristian Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Alvares, Diego Janish. Universidad Federal do Río Grande del Sur. Instituto Biociencias. Departamento de Zoología. Laboratorio de Herpetologia; BrasilFil: Avila, Luciano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

    Learning spatial aversion is sensory-specific in the hematophagous insect Rhodnius prolixus

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    Even though innate behaviors are essential for assuring quick responses to expected stimuli, experience-dependent behavioral plasticity confers an advantage when unexpected conditions arise. As being rigidly responsive to too many stimuli can be biologically expensive, adapting preferences to time-dependent relevant environmental conditions provide a cheaper and wider behavioral reactivity. According to their specific life habits, animals prioritize different sensory modalities to maximize environment exploitation. Besides, when mediating learning processes, the salience of a stimulus usually plays a relevant role in determining the intensity of an association. Then, sensory prioritization might reflect an heterogeneity in the cognitive abilities of an individual. Here, we analyze in the kissing bug Rhodnius prolixus if stimuli from different sensory modalities generate different cognitive capacities under an operant aversive paradigm. In a 2-choice walking arena, by registering the spatial distribution of insects over an experimental arena, we evaluated firstly the innate responses of bugs confronted to mechanical (rough substrate), visual (green light), thermal (32°C heated plate), hygric (humidified substrate), gustatory (sodium chloride), and olfactory (isobutyric acid) stimuli. In further experimental series bugs were submitted to an aversive operant conditioning by pairing each stimulus with a negative reinforcement. Subsequent tests allowed us to analyze if the innate behaviors were modulated by such previous aversive experience. In our experimental setup mechanical and visual stimuli were neutral, the thermal cue was attractive, and the hygric, gustatory and olfactory ones were innately aversive. After the aversive conditioning, responses to the mechanical, the visual, the hygric and the gustatory stimuli were modulated while responses to the thermal and the olfactory stimuli remained rigid. We present evidences that the spatial learning capacities of R. prolixus are dependent on the sensory modality of the conditioned stimulus, regardless their innate valence (i.e., neutral, attractive, or aversive). These differences might be given by the biological relevance of the stimuli and/or by evolutionary aspects of the life traits of this hematophagous insect.Fil: Minoli, Sebastian. Universidad de Buenos Aires; ArgentinaFil: Cano, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pontes, Gina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Magallanes, Amorina. Universidad de Buenos Aires; ArgentinaFil: Roldán, Nahuel. Universidad de Buenos Aires; ArgentinaFil: Barrozo, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Identification and Preliminary Validation in Mouse Models of Circulating Biomarkers of Pancreatic Cancer

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    Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal oncological malignancies in humans. Not-specific symptoms and lack of early diagnostic strategies, frequently lead to late diagnosis which limited therapeutic possibilities (Korc, 2007). The present study aimed at identifying novel potential serum biomarkers for early detection of PDAC.In the first phase, two different mouse models of PDAC were characterized: genetically engineered mice (GEMs) (Hingorani et al., 2003) which developed PanIN (pancreatic intraepithelial neoplasia) lesions and three PDAC patient-derived xenograft.In the second phase, the two mouse models were used to evaluate the reliability of 3 circulating molecules as early diagnostic biomarkers of PDAC. The plasma levels of matrix metalloproteinase-7 (MMP-7), tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) and thrombospondin-2 (THBS-2) were tested on GEMs and PDAC-PDXs bearing mice by ELISA tests, during tumor development, and at sacrifice by immunohistochemistry performed on pancreatic tissue.The three established PDAC-PDXs were found to better reproduce the tumor of origin after intra-pancreas transplantation compared to the subcutaneous ones, and to maintain molecular and morphological features over different passages.At sacrifice, histopathological analysis demonstrated different stages of PanIN lesions in GEMs and the presence of a well-developed pancreatic tumor in all the mice orthotopically inoculated with the PDAC-PDXs.Plasma levels of MMP-7, TIMP-1 and THBS-2 were progressively upregulated, over the time, in GEMs and in PDAC-PDX bearing mice.In both animal models, immunohistochemistry revealed stromal immunoreactivity for TIMP-1 and THBS-2, while MMP-7 expression was mainly localized on epithelial cells. All the markers showed progressive increase of staining intensity along with PanIN progression.In conclusion, the investigated circulating molecules represent promising biomarkers for early diagnosis of PDAC and to monitor the response to treatment in human patients. Both tumoral cells and associated stroma play a role in the production and release of such biomarkers

    Tumor Microenvironment In Experimental Models Of Human Cancer: Morphological Investigational Approaches

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    Introduction. Tumor microenvironment (TME) is defined as the non-tumoral part of tumors. It is composed of different cell populations and structures (such as tumor-associated vasculature, immune-inflammatory cells, fibroblasts…) (Hanahan and Coussens, 2012). TME could either promote or antagonize tumor growth and has a great potential as target for novel therapeutic strategies. Along with several methods (i.e. molecular assays), morphological techniques allow to evaluate the components of TME in the setting of their action. The aim of this work was to set up and define valuable morphological approaches useful in the investigation of the TME.Materials and methods. Histological and immunohistochemical techniques, along with digital image analysis, were tested on experimental mouse models (both xenograft and genetically engineered mice) of four different human tumors (ovarian cancer, pancreatic ductal adenocarcinoma (PDAC), colon adenocarcinoma, thyroid carcinoma).Results. Concerning the vascular compartment, CD31 immunostaining and double-immunofluorescence with CD31 and a-SMA (pericytes marker) allowed to respectively quantify vessels and evaluate their maturation degree. Immunohistochemical detection of previously administrated Pimonidazole, revealed variable extended areas of hypoxia within tumoral masses in a consistent pattern between frozen and formalin-fixed paraffin-embedded samples.Concerning the stromal component, anti-human MHC I and specie-specific markers for Vimentin demonstrated the host-derivation of stroma in xenotumors, while Sirius Red histochemical staining allowed the quantification of desmoplasia in models of PDAC.Concerning immune-inflammatory cells, an immunohistochemical panel with CD3 (T lymphocytes), B220 (B lymphocytes), MPO (neutrophils) and Iba-1 (macrophages), showed high reliability in characterizing the tumoral infiltrate. Moreover, the application of markers specific for different macrophage subsets confirmed the higher prevalence of M2 (Arginase I positive) on M1 (iNOS positive) macrophages. YM1 demonstrated a low performance in detecting the M2 population (Fig. 1).Discussion and conclusions. Due to the microenvironmental heterogeneity which influence tumor development and biological behavior, a sole quantification is unreliable for characterizing the TME. Considering that, morphological techniques proved to be a valuable approach, allowing the evaluation of the spatial distribution and mutual interaction between the different elements. Additional studies are needed for further investigate the biological significance of spatial distribution of the components of the TME

    Dislodgement effect of natural semiochemicals released by disturbed triatomines: a possible alternative monitoring tool

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    pre-printThe quick detection of domestic and peridomestic triatomines in their environments becomes difficult without the use of dislodgement substances that flush them out from their shelters. At present, tetramethrin 0.2% is being widely used in control programs. Although it is an efficient dislodging agent, its toxicity might affect the health of captured triatomines, of other insects and, to a lesser extent, of other animals, including humans. Here, we tested if semiochemicals released by disturbed adults of Triatoma infestans and/or Rhodnius prolixus can make larvae of the same species exit from their refuges. In a walking olfactometer we found that: 1) larvae of T. infestans were repelled by the odors released by disturbed adults of their own species and of R. prolixus, 2) larvae of R. prolixus did not change their behavior in the presence of odors released by adults of both species, and 3) activity levels were not modulated by these odors in any of both species. Besides, in pseudo-natural conditions we found an increased flushing-out activity of larvae of T. infestans when their shelters were sprayed with isobutyric acid or 3-pentanol, and of larvae of R. prolixus when sprayed with 3-methyl-1-butanol. We succeeded in this work to dislodge larvae of triatomines from artificial shelters using natural volatile compounds, allowing the capture of live bugs for further investigations (e.g., xenodiagnosis or genetic studies) and favoring ecological aspects (e.g., minimizing environmental insecticide-contamination and non-targeted mortality)

    New records of Pristidactylus nigroiugulus Cei, Scolaro & Videla, 2001 (squamata: Leiosauridae) with a geographic distribution map

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    We provide new geographic records for Pristidactylus nigroiugulus Cei, Scolaro & Videla, 2001 from Argentina. We present the first record for Santa Cruz province and the southernmost records of the species based on lizards collected in the austral summers of 2012/2013 and 2013/2014. Based on a museum specimen, we extend the species distribution to the eastern part of the Somuncurá Plateau. An updated distributional map is included.Fil: Avila, Luciano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Minoli, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Perez, Cristian Hernan Fulvio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Gonzalez Marin, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Morando, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentin
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