A numerical model of chemical weathering in soil horizons and underlying bedrock (WITCH) has been coupled to a numerical model of water and carbon cycles in forest ecosystems (ASPECTS) to simulate ...the concentration of major species within the soil horizons and the stream of the Strengbach granitic watershed, located in the Vosges Mountains (France). For the first time, simulations of solute concentrations in soil layers and in the catchment river have been performed on a seasonal basis. The model is able to reproduce the concentrations of most major species within the soil horizons, as well as catching the first-order seasonal fluctuations of aqueous calcium, magnesium and silica concentrations. However, the WITCH model underestimates concentrations of Mg
2+ and silica at the spring of the catchment stream, and significantly underestimates Ca
2+ concentration. The deficit in calculated calcium can be compensated for by dissolution of trace apatite disseminated in the bedrock. However, the resulting increased Ca
2+ release yields important smectite precipitation in the deepest model layer (in contact with the bedrock) and subsequent removal of large amount of silica and magnesium from solution. In contrast, the model accurately accounts for the concentrations of major species (Ca, Mg and silica) measured in the catchment stream when precipitation of clay minerals is not allowed. The model underestimation of Mg
2+ and H
4SiO
4 concentrations when precipitation of well crystallized smectites is allowed strongly suggests that precipitation of well crystallized clay minerals is overestimated and that more soluble poorly crystallized and amorphous materials may be forming. In agreement with observations on other watersheds draining granitic rocks, this study indicates that highly soluble trace calcic phases control the aqueous calcium budget in the Strengbach watershed.
Simulating vegetation photosynthetic productivity (or gross primary production, GPP) is a critical feature of the biome models used for impact assessments of climate change. We conducted a ...benchmarking of global GPP simulated by eight biome models participating in the second phase of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP2a) with four meteorological forcing datasets (30 simulations), using independent GPP estimates and recent satellite data of solar-induced chlorophyll fluorescence as a proxy of GPP. The simulated global terrestrial GPP ranged from 98 to 141 Pg C yr−1 (1981-2000 mean); considerable inter-model and inter-data differences were found. Major features of spatial distribution and seasonal change of GPP were captured by each model, showing good agreement with the benchmarking data. All simulations showed incremental trends of annual GPP, seasonal-cycle amplitude, radiation-use efficiency, and water-use efficiency, mainly caused by the CO2 fertilization effect. The incremental slopes were higher than those obtained by remote sensing studies, but comparable with those by recent atmospheric observation. Apparent differences were found in the relationship between GPP and incoming solar radiation, for which forcing data differed considerably. The simulated GPP trends co-varied with a vegetation structural parameter, leaf area index, at model-dependent strengths, implying the importance of constraining canopy properties. In terms of extreme events, GPP anomalies associated with a historical El Niño event and large volcanic eruption were not consistently simulated in the model experiments due to deficiencies in both forcing data and parameterized environmental responsiveness. Although the benchmarking demonstrated the overall advancement of contemporary biome models, further refinements are required, for example, for solar radiation data and vegetation canopy schemes.
Entirely biological human tissue-engineered blood vessels (TEBV) were previously developed for clinical use. Tissue-engineered models have also proven to be valuable tools in disease modelling. ...Moreover, there is a need for complex geometry TEBV for study of multifactorial vascular pathologies, such as intracranial aneurysms. The main goal of the work reported in this article was to produce an entirely human branched small-caliber TEBV. The use of a novel spherical rotary cell seeding system allows effective and uniform dynamic cell seeding for a viable in vitro tissue-engineered model. In this report, the design and fabrication of an innovative seeding system with random spherical 360° rotation is described. Custom made seeding chambers are placed inside the system and hold Y-shaped polyethylene terephthalate glycol (PETG) scaffolds. The seeding conditions, such as cell concentration, seeding speed and incubation time were optimized via count of cells adhered on the PETG scaffolds. This spheric seeding method was compared to other approaches, such as dynamic and static seeding, and clearly shows uniform cell distribution on PETG scaffolds. With this simple to use spherical system, fully biological branched TEBV constructs were also produced by seeding human fibroblasts directly on custom-made complex geometry PETG mandrels. The production of patient-derived small-caliber TEBVs with complex geometry and optimized cellular distribution all along the vascular reconstructed may be an innovative way to model various vascular diseases such as intracranial aneurysms.
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting motor neurons of the brain and spinal cord, leading to progressive paralysis and death. Interestingly, many skin changes ...have been reported in ALS patients, but never as yet fully explained. These observations could be due to the common embryonic origin of the skin and neural tissue known as the ectodermal germ layer. Following the first observation in ALS patients’ skin by Dr Charcot in the 19th century, in the absence of bedsores unlike other bedridden patients, other morphological and molecular changes have been observed. Thus, the skin could be of interest in the study of ALS and other neurodegenerative diseases. This review summarizes skin changes reported in the literature over the years and discusses about a novel
ALS tissue-engineered skin model, derived from patients, for the study of ALS.
Some authors consider this list incomplete and believe that at least 3 other major zoonoses-anthrax, bovine tuberculosis, and brucellosis-should be included 3. ...while some public-private ...partnerships-e.g., the Global Alliance for Livestock Veterinary Medicines, GALVmed (https://www.galvmed.org/)-now target major livestock diseases impacting smallholders by connecting academia, public research institutes, and the pharmaceutical sector, no strictly animal disease (i.e., nonzoonotic) has been labelled “neglected”. ...animal diseases impact households through livestock mortality, decreased production or product quality (meat, milk, leather), and disorganised value chains and agroindustries, resulting in income losses 7 that, in turn, affect food security and human health. ...the impact may be assessed by studying spillover mechanisms hampering the functioning of other economic agents in markets and supply chains, thereby leading to greater food insecurity (lower prices, trade embargoes). DALY indicators solely measure the burden of human diseases and are calculated based on the number of years lost due to a disability linked to poor health and to premature mortality due to disease. ...at the community level, participatory methods could be used to involve smallholders in determining disease priorities and to understand their perception of sanitary risks.
Terrestrial gross primary productivity (GPP) is the largest component of the global carbon cycle and a key process for understanding land ecosystems dynamics. In this study, we used GPP estimates ...from a combination of eight global biome models participating in the Inter-Sectoral Impact-Model Intercomparison Project phase 2a (ISIMIP2a), the Moderate Resolution Spectroradiometer (MODIS) GPP product, and a data-driven product (Model Tree Ensemble, MTE) to study the spatiotemporal variability of GPP at the regional and global levels. We found the 2000-2010 total global GPP estimated from the model ensemble to be 117 ± 13 Pg C yr−1 (mean ± 1 standard deviation), which was higher than MODIS (112 Pg C yr−1), and close to the MTE (120 Pg C yr−1). The spatial patterns of MODIS, MTE and ISIMIP2a GPP generally agree well, but their temporal trends are different, and the seasonality and inter-annual variability of GPP at the regional and global levels are not completely consistent. For the model ensemble, Tropical Latin America contributes the most to global GPP, Asian regions contribute the most to the global GPP trend, the Northern Hemisphere regions dominate the global GPP seasonal variations, and Oceania is likely the largest contributor to inter-annual variability of global GPP. However, we observed large uncertainties across the eight ISIMIP2a models, which are probably due to the differences in the formulation of underlying photosynthetic processes. The results of this study are useful in understanding the contributions of different regions to global GPP and its spatiotemporal variability, how the model- and observational-based GPP estimates differ from each other in time and space, and the relative strength of the eight models. Our results also highlight the models' ability to capture the seasonality of GPP that are essential for understanding the inter-annual and seasonal variability of GPP as a major component of the carbon cycle.
Delaying clinical disease onset would greatly reduce neurodegenerative disease burden, but the mechanisms influencing early preclinical progression are poorly understood. Here, we show that in mouse ...models of familial motoneuron (MN) disease, SOD1 mutants specifically render vulnerable MNs dependent on endogenous neuroprotection signaling involving excitability and mammalian target of rapamycin (mTOR). The most vulnerable low-excitability FF MNs already exhibited evidence of pathology and endogenous neuroprotection recruitment early postnatally. Enhancing MN excitability promoted MN neuroprotection and reversed misfolded SOD1 (misfSOD1) accumulation and MN pathology, whereas reducing MN excitability augmented misfSOD1 accumulation and accelerated disease. Inhibiting metabotropic cholinergic signaling onto MNs reduced ER stress, but enhanced misfSOD1 accumulation and prevented mTOR activation in alpha-MNs. Modulating excitability and/or alpha-MN mTOR activity had comparable effects on the progression rates of motor dysfunction, denervation, and death. Therefore, excitability and mTOR are key endogenous neuroprotection mechanisms in motoneurons to counteract clinically important disease progression in ALS.
•A growing excitability signaling deficit in motoneurons drives disease in ALS mice•Enhancing motoneuron excitability provides neuroprotection to FALS motoneurons•Metabotropic cholinergic signaling provides neuroprotection through mTOR•Enhancing mTOR activation while reducing ER stress delays disease progression
Saxena et al. show that in mouse models of familial motoneuron (MN) disease, disease-associated superoxide dismutase 1 (SOD1) mutants render vulnerable motoneurons dependent on endogenous neuroprotection involving excitability and mammalian target of Rapamycin (mTOR). Enhancing excitability signaling in motoneurons counteracts clinically important disease progression.
Quantifying variability in protein expression is a major goal of systems biology and cell-to-cell variability in subcellular localization pattern has not been systematically quantified.
We define a ...local measure to quantify cell-to-cell variability in high-throughput microscope images and show that it allows comparable measures of variability for proteins with diverse subcellular localizations. We systematically estimate cell-to-cell variability in the yeast GFP collection and identify examples of proteins that show cell-to-cell variability in their subcellular localization.
Automated image analysis methods can be used to quantify cell-to-cell variability in microscope images.
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