Plant cell walls tackling climate change : insights into plant cell wall remodeling, its regulation, and biotechnological strategies to improve crop adaptations and photosynthesis in response to global warming

Plant cell wall (CW) is a complex and intricate structure that performs several functions throughout the plant life cycle. The CW of plants is critical to the maintenance of cells\u2019 structural integrity by resisting internal hydrostatic pressures, providing flexibility to support cell division and expansion during tissue differentiation, and acting as an environmental barrier that protects the cells in response to abiotic stress. Plant CW, comprised primarily of polysaccharides, represents the largest sink for photosynthetically fixed carbon, both in plants and in the biosphere. The CW structure is highly varied, not only between plant species but also among different organs, tissues, and cell types in the same organism. During the developmental processes, the main CW components, i.e., cellulose, pectins, hemicelluloses, and different types of CW-glycoproteins, interact constantly with each other and with the environment to maintain cell homeostasis. Differentiation processes are altered by positional effect and are also tightly linked to environmental changes, affecting CW both at the molecular and biochemical levels. The negative effect of climate change on the environment is multifaceted, from high temperatures, altered concentrations of greenhouse gases such as increasing CO2 in the atmosphere, soil salinity, and drought, to increasing frequency of extreme weather events taking place concomitantly, therefore, climate change affects crop productivity in multiple ways. Rising CO2 concentration in the atmosphere is expected to increase photosynthetic rates, especially at high temperatures and under water-limited conditions. This review aims to synthesize current knowledge regarding the effects of climate change on CW biogenesis and modification. We discuss specific cases in crops of interest carrying cell wall modifications that enhance tolerance to climate change-related stresses; from cereals such as rice, wheat, barley, or maize to dicots of interest such as brassica oilseed, cotton, soybean, tomato, or potato. This information could be used for the rational design of genetic engineering traits that aim to increase the stress tolerance in key crops. Future growing conditions expose plants to variable and extreme climate change factors, which negatively impact global agriculture, and therefore further research in this area is critical

Carbohydrate reserves and seed development : an overview

Seeds are one of the most important food sources, providing humans and animals with essential nutrients. These nutrients include carbohydrates, lipids, proteins, vitamins and minerals. Carbohydrates are one of the main energy sources for both plant and animal cells and play a fundamental role in seed development, human nutrition and the food industry. Many studies have focused on the molecular pathways that control carbohydrate flow during seed development in monocot and dicot species. For this reason, an overview of seed biodiversity focused on the multiple metabolic and physiological mechanisms that govern seed carbohydrate storage function in the plant kingdom is required. A large number of mutants affecting carbohydrate metabolism, which display defective seed development, are currently available for many plant species. The physiological, biochemical and biomolecular study of such mutants has led researchers to understand better how metabolism of carbohydrates works in plants and the critical role that these carbohydrates, and especially starch, play during seed development. In this review, we summarize and analyze the newest findings related to carbohydrate metabolism\u2019s effects on seed development, pointing out key regulatory genes and enzymes that influence seed sugar import and metabolism. Our review also aims to provide guidelines for future research in the field and in this way to assist seed quality optimization by targeted genetic engineering and classical breeding programs

Las anomalías nocturnas de fase en MRP y el oxigeno atómico en la mesosfera - Parte I: datos experimentales

Se han analizado los registros de muy baja frecuencia (MBF) recibidos en Tucumán entre 1973 y 1976, buscando anomalías nocturnas de fase (ANF) del tipo observado por Chilton y Radicella en el mismo circuito transecuatorial en 1963-1964, encontrándose un total de 8 noches que presentan dichas anomalías de manera bien definida. Utilizando la teoría de guía de ondas de Wait y el modelo de concentración electrónica obtenido por dos de los autores (R. y R.) se ha calculado la evolución de la altura de la guía de ondas durante las anomalías como así también los cambios de gradiente de conductividad en la región de reflexión. Los resultados muestran que la base de la capa D nocturna ha descendido hasta 12 Km durante la anomalía más pronunciada.Tucumán VLF records for the 1973-1976 period have been analjr zed, looking for nighttime phase anomalies (NPA) of the type observed by Chilton and Radicella for the same transequatorial propa gation path in 1963-1964. Eight NPA have been found. The height and conductivity gradient variations of the waveguide during the NPA have been computed, using the Wait’s waveguide theory and the electron concentration model obtained by two of the authors (R, and R.). The results show that the base of the D region has descended up to 12 Km dúring the largest anomaly.Asociación Argentina de Geofísicos y Geodesta

Acoplamiento de la alta y baja ionosfera durante la tormenta geomagnética del 26 de marzo de 1976

Se realiza el análisis comparativo del comportamiento dé diferentes parámetros de las regiones D, E y F para Tucumán durante la tormenta del 26 de marzo de 1976. Para el estudio de las capas E y F se trabajo con registros del sondador vertical. Para la región D se infiere el comportamiento de la misma a través de registros de fase y amplitud en señales de muy baja frecuencia emitidas por la estación NAA. El rasgo más saliente del presente estudio indica que la perturbación ionosférica que, iniciada en la zona auroral de la región F y propagada hacia bajas latitudes en camino horizontal, también mostraría una componente vertical que llega a afectar la región D. En la comparación de parámetros indicadores de concentración electrónica se observa comportamiento tanto en fase como en contrafase.A comparative analysis of the behaviour of the D,E and F regions physical parameters over Tucumán for the 26 of march, 1976 storm, has been realized. Tucumán vertical sounder records were used for the E and F regions data. The behaviour of D region has been inferred through phase and amplitude records of VLF signals emitted by the NAA station. One important feature of the present study indicates that the ionospheric perturbation, with origin in the auroral zone and propagating equatorward in a horizontal way, would also show a vertical component reaching the D-region. After comparing parameters indicating electron concentration changes a behaviour in phase as well as in counterphase has been observed.Asociación Argentina de Geofísicos y Geodesta

The Antidiabetic Effect of MSCs Is Not Impaired by Insulin Prophylaxis and Is Not Improved by a Second Dose of Cells

Type 1 diabetes mellitus (T1D) is due to autoimmune destruction of pancreatic beta-cells. Previously, we have shown that intravenously administered bone marrow-derived multipotent mesenchymal stromal cells (MSCs) allows pancreatic islet recovery, improves insulin secretion and reverts hyperglycemia in low doses streptozotocin (STZ)-induced diabetic mice. Here we evaluate whether insulin prophylaxis and the administration of a second dose of cells affect the antidiabetic therapeutic effect of MSC transplantation. Insulitis and subsequent elimination of pancreatic beta-cells was promoted in C57BL/6 mice by the injection of 40 mg/kg/day STZ for five days. Twenty-four days later, diabetic mice were distributed into experimental groups according to if they received or not insulin and/or one or two doses of healthy donor-derived MSCs. Three and half months later: glycemia, pancreatic islets number, insulinemia, glycated hemoglobin level and glucose tolerance were determined in animals that did not received exogenous insulin for the last 1.5 months. Also, we characterized MSCs isolated from mice healthy or diabetic. The therapeutic effect of MSC transplantation was observed in diabetic mice that received or not insulin prophylaxis. Improvements were similar irrespective if they received one or two doses of cells. Compared to MSCs from healthy mice, MSCs from diabetic mice had the same proliferation and adipogenic potentials, but were less abundant, with altered immunophenotype and no osteogenic potential

Repeatability of food frequency assessment tools in relation to the number of items and response categories included

Background: Accuracy of a measurement is a cornerstone in research in order to make robust conclusions about the research hypothesis. Objective: To examine whether the number of items (questions) and the number of responses of consumption included in nutritional assessment tools influence their repeatability. Methods: During 2009, 400 participants (250 from Greece, 37±13 yrs, 34% males and 150 participants from Spain, 39±17 yrs, 41% males) completed a diet index with 11-items and binary (yes/no) responses, a diet-index with 11-items and 6-scale responses, a 36-item and a 76-item food frequency questionnaire (FFQ) with 6-scale responses. Participants completed these tools, twice, within 15-days period. Spearman-Brown (rsb), Kendall’s tau coefficients and the Bland-Altman method were applied to answer the research hypothesis. Results: The highest repeatability coefficient was observed for the 11-items with binary responses index (rsb=0.948, p<0.001), followed by the 11-items with 6-scale responses index (rsb=0.943, p<0.001), the 36-item (rsb=0.936, p<0.001) and the 76-item FFQs (rsb=0.878, p<0.001). Statistical comparisons revealed no significant differences between repeatability coefficients of the first three tools (p>0.23); whereas the aforementioned tools had significantly higher repeatability coefficients as compared with the 76-item FFQ (p=0.002). Sub-group analyses by gender, education, smoking and clinical status, confirmed the aforementioned results. Conclusion: Repeatability has been revealed for all food frequency assessment tools used, irrespective of the number of items or the number of responses included

The Use of Biomaterials in Islet Transplantation

Pancreatic islet transplantation is a therapeutic option to replace destroyed β cells in autoimmune diabetes. Islets are transplanted into the liver via the portal vein; however, inflammation, the required immunosuppression, and lack of vasculature decrease early islet viability and function. Therefore, the use of accessory therapy and biomaterials to protect islets and improve islet function has definite therapeutic potential. Here we review the application of niche accessory cells and factors, as well as the use of biomaterials as carriers or capsules, for pancreatic islet transplantation

The bHLH transcription factor SPATULA enables cytokinin signaling, and both activate auxin biosynthesis and transport genes at the medial domain of the gynoecium

[EN] Fruits and seeds are the major food source on earth. Both derive from the gynoecium and, therefore, it is crucial to understand the mechanisms that guide the development of this organ of angiosperm species. In Arabidopsis, the gynoecium is composed of two congenitally fused carpels, where two domains: medial and lateral, can be distinguished. The medial domain includes the carpel margin meristem (CMM) that is key for the production of the internal tissues involved in fertilization, such as septum, ovules, and transmitting tract. Interestingly, the medial domain shows a high cytokinin signaling output, in contrast to the lateral domain, where it is hardly detected. While it is known that cytokinin provides meristematic properties, understanding on the mechanisms that underlie the cytokinin signaling pattern in the young gynoecium is lacking. Moreover, in other tissues, the cytokinin pathway is often connected to the auxin pathway, but we also lack knowledge about these connections in the young gynoecium. Our results reveal that cytokinin signaling, that can provide meristematic properties required for CMM activity and growth, is enabled by the transcription factor SPATULA (SPT) in the medial domain. Meanwhile, cytokinin signaling is confined to the medial domain by the cytokinin response repressor ARABIDOPSIS HISTIDINE PHOSPHOTRANSFERASE 6 (AHP6), and perhaps by ARR16 (a type-A ARR) as well, both present in the lateral domains (presumptive valves) of the developing gynoecia. Moreover, SPT and cytokinin, probably together, promote the expression of the auxin biosynthetic gene TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 (TAA1) and the gene encoding the auxin efflux transporter PIN-FORMED 3 (PIN3), likely creating auxin drainage important for gynoecium growth. This study provides novel insights in the spatiotemporal determination of the cytokinin signaling pattern and its connection to the auxin pathway in the young gynoecium.IRO, VMZM, HHU and PLS were supported by the Mexican National Council of Science and Technology (CONACyT) with a PhD fellowship (210085, 210100, 243380 and 219883, respectively). Work in the SDF laboratory was financed by the CONACyT grants CB-2012-177739, FC-2015-2/1061, and INFR-2015-253504, and NMM by the CONACyT grant CB-2011-165986. SDF, CF and LC acknowledge the support of the European Union FP7-PEOPLE-2009-IRSES project EVOCODE (grant no. 247587) and H2020-MSCARISE-2015 project ExpoSEED (grant no. 691109). SDF also acknowledges the Marine Biological Laboratory (MBL) in Woods Hole for a scholarship for the Gene Regulatory Networks for Development Course 2015 (GERN2015). IE acknowledges the International European Fellowship-METMADS project and the Universita degli Studi di Milano (RTD-A; 2016). Research in the laboratory of MFY was funded by NSF (grant IOS-1121055), NIH (grant 1R01GM112976-01A1) and the Paul D. Saltman Endowed Chair in Science Education (MFY). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Reyes Olalde, J.; Zuñiga, V.; Serwatowska, J.; Chávez Montes, R.; Lozano-Sotomayor, P.; Herrera-Ubaldo, H.; Gonzalez Aguilera, K.... (2017). The bHLH transcription factor SPATULA enables cytokinin signaling, and both activate auxin biosynthesis and transport genes at the medial domain of the gynoecium. PLoS Genetics. 13(4):1-31. https://doi.org/10.1371/journal.pgen.1006726S131134Reyes-Olalde, J. I., Zuñiga-Mayo, V. M., Chávez Montes, R. A., Marsch-Martínez, N., & de Folter, S. (2013). Inside the gynoecium: at the carpel margin. Trends in Plant Science, 18(11), 644-655. doi:10.1016/j.tplants.2013.08.002Alvarez-Buylla, E. 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Liver cell therapy: is this the end of the beginning?

The prevalence of liver diseases is increasing globally. Orthotopic liver transplantation is widely used to treat liver disease upon organ failure. The complexity of this procedure and finite numbers of healthy organ donors have prompted research into alternative therapeutic options to treat liver disease. This includes the transplantation of liver cells to promote regeneration. While successful, the routine supply of good quality human liver cells is limited. Therefore, renewable and scalable sources of these cells are sought. Liver progenitor and pluripotent stem cells offer potential cell sources that could be used clinically. This review discusses recent approaches in liver cell transplantation and requirements to improve the process, with the ultimate goal being efficient organ regeneration. We also discuss the potential off-target effects of cell-based therapies, and the advantages and drawbacks of current pre-clinical animal models used to study organ senescence, repopulation and regeneration