Climate resilience and the human-water dynamics. The case of tomato production in Morocco.

In Morocco, droughts are an increasing threat affecting water availability, agricultural production and producers' livelihoods. Moreover, water demand for irrigation has led to overexploitation of the groundwater table causing significant natural resource management challenges. The combination of groundwater changes and increasing drought risk raises concerns about the ability of agricultural producers to be resilient against drought. In this study, we describe the interactions of environmental and socioeconomic processes which influence farmers' livelihoods involved in tomato production in Morocco. Building on system dynamics modelling tools, we aim to improve the understanding of the long-term dynamic behavior of water management and to explore plausible policy scenarios necessary for sustainable and resilient water resource management and agricultural development. Our results show that tomato production is not yet severely impacted by droughts. However, droughts are accelerating the process of groundwater depletion, impacting farmers' livelihoods, by decreasing crop productivity and reducing farmer's revenue over a longer time period, especially since tomatoes are a high-value crop. Therefore, integrated and effective policies are presented as a set of measures for a systemic enhancement of resilience. We conclude that a more radical approach toward water resource conservation and upholding the most vulnerable producers has to be adopted in order to enhance a sustainable and inclusive resilience of the tomato production in Morocco.

Warming and redistribution of nitrogen inputs drive an increase in terrestrial nitrous oxide emission factor.

Anthropogenic nitrogen inputs cause major negative environmental impacts, including emissions of the important greenhouse gas N2O. Despite their importance, shifts in terrestrial N loss pathways driven by global change are highly uncertain. Here we present a coupled soil-atmosphere isotope model (IsoTONE) to quantify terrestrial N losses and N2O emission factors from 1850-2020. We find that N inputs from atmospheric deposition caused 51% of anthropogenic N2O emissions from soils in 2020. The mean effective global emission factor for N2O was 4.3 ± 0.3% in 2020 (weighted by N inputs), much higher than the surface area-weighted mean (1.1 ± 0.1%). Climate change and spatial redistribution of fertilisation N inputs have driven an increase in global emission factor over the past century, which accounts for 18% of the anthropogenic soil flux in 2020. Predicted increases in fertilisation in emerging economies will accelerate N2O-driven climate warming in coming decades, unless targeted mitigation measures are introduced.

Synthesis of dextran-based chain transfer agent for RAFT-mediated polymerization and glyco-nanoobjects formulation.

Glycopolymers based on dextran are frequently prepared via ATRP, whereas the use of RAFT polymerization is strangely limited due to the difficult synthesis of Dextran-based macromolecular chain transfer agent (DexCTA). The aim of this work is to establish a controlled and reproducible methodology for its preparation. Direct esterification of the hydroxyl dextran functions is the most common method. Our study shows that this latter leads to a very low degree of functionalization. As alternative, we report a reproductible multistep strategy consisting of oxidation, amination, and amidation reactions. Various DexCTAs with tunable degree of substitution (respectively 0.025, 0.045, and 0.06) were successfully prepared. As proof of concept, one of the DexCTAs was involved in the photo-mediated RAFT polymerization of hydroxypropyl methacrylate in DMSO to prepare amphiphilic Dex-g-PHPMA glycopolymers, which can self-assemble in water into monodisperse spherical nano-objects. MTT assays revealed the biocompatibility of all dextran derivatives.

Injectable PLA-based in situ forming implants for controlled release of Ivermectin a BCS Class II drug: solvent selection based on physico-chemical characterization.

In situ forming implants (ISI) prepared from biodegradable polymers such as poly(D,L-lactide) (PLA) and biocompatible solvents can be used to obtain sustained drug release after parenteral administration. The aim of this work was to study the effect of several biocompatible solvents with different physico-chemical properties on the release of ivermectin (IVM), an antiparasitic BCS II drug, from in situ forming PLA-based implants. The solvents evaluated were N-methyl-2-pyrrolidone (NMP), 2-pyrrolidone (2P), triacetine (TA) and benzyl benzoate (BB). Hansen's solubility parameters of solvents were used to explain polymer/solvent interactions leading to different rheological behaviours. The stability of the polymer and drug in the solvents were also evaluated by size exclusion and high performance liquid chromatography, respectively. The two major factors determining the rate of IVM release from ISI were miscibility of the solvent with water and the viscosity of the polymer solutions. In general, the release rate increased with increasing water miscibility of the solvent and decreasing viscosity in the following order NMP>2P>TA>BB. Scanning electron microscopy revealed a relationship between the rate of IVM release and the surface porosity of the implants, release being higher as implant porosity increased. Finally, drug and polymer stability in the solvents followed the same trends, increasing when polymer-solvent affinities and water content in solvents decreased. IVM degradation was accelerated by the acid environment generated by the degradation of the polymer but the drug did not affect PLA stability.

Biodegradable nanoparticles made from polylactide-grafted dextran copolymers.

Polysaccharide-covered polyester nanoparticles were prepared using the emulsion/solvent evaporation process. The core of the nanoparticles was made either of PLA or of a blend of polylactide and polylactide-grafted dextran copolymer in various proportions. The surface of the nanoparticles was covered by dextran chains via the use of water-soluble polylactide-grafted dextrans as polymeric stabilizers during the emulsification step. The characteristics of the nanoparticles (size, surface coverage, thickness of superficial layer, colloidal stability) were correlated to the structural parameters (length and number of polylactide grafts) of the copolymers as well as to their surface active properties. The complete biodegradability of the nanoparticles was evaluated by considering the rate of hydrolysis of polylactide grafts in phosphate buffer and the rate of enzymatic degradation of dextran backbone by dextranase.

[Dietary supplement use among adolescents in Germany. Results of EsKiMo]. / Supplementenkonsum bei Jugendlichen in Deutschland. Ergebnisse aus EsKiMo.

In 2006, 20 % of adolescents aged 12-17 years used dietary supplements. Persons with high physical activity levels as well as those with high education levels consumed dietary supplements more often than others. Many supplement users used only one single-nutrient supplement. A similarly large proportion of users consumed one supplement with multiple nutrients. Most often supplements containing vitamin C, magnesium, B-vitamins, vitamin E and calcium were used.

Emulsifying properties of biodegradable polylactide-grafted dextran copolymers.

Amphiphilic glycopolymers, polylactide-grafted dextran copolymers (Dex-g-PLA), were synthesized with a well-controlled architecture obtained through a three-step procedure: partial silylation of the dextran hydroxyl groups, ring-opening polymerization of D,L-lactide initiated from remaining hydroxyl groups, silylether deprotection under very mild conditions. Depending on their proportion in polylactide (PLA), these copolymers exhibited solubility either in water or in organic solvents. The emulsifying properties of these glycopolymers were studied: depending on their PLA-to-dextran ratio, they were able to stabilize either direct or inverse emulsions. Droplet size was related to the amount of amphiphilic copolymer in the continuous phase. The aging mechanism of both direct and inverse emulsions was shown to be Ostwald ripening in the first weeks following preparation. Finally inverse miniemulsion copolymerization of acrylamide and N, N'-methylenebisacrylamide was performed in the presence of an amphiphilic Dex-g-PLA stabilizer. Polyacrylamide hydrogel nanoparticles were prepared in that way.

The impact of agricultural soil erosion on the global carbon cycle.

Agricultural soil erosion is thought to perturb the global carbon cycle, but estimates of its effect range from a source of 1 petagram per year(-1) to a sink of the same magnitude. By using caesium-137 and carbon inventory measurements from a large-scale survey, we found consistent evidence for an erosion-induced sink of atmospheric carbon equivalent to approximately 26% of the carbon transported by erosion. Based on this relationship, we estimated a global carbon sink of 0.12 (range 0.06 to 0.27) petagrams of carbon per year(-1) resulting from erosion in the world's agricultural landscapes. Our analysis directly challenges the view that agricultural erosion represents an important source or sink for atmospheric CO2.

[EsKiMo - the nutrition module in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]. / EsKiMo - Das Ernährungsmodul im Kinder- und Jugendgesundheitssurvey (KiGGS).

In a module of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS), the dietary behaviour of 6-17-year-olds was assessed from January to December 2006. The study, named EsKiMo (Eating Study as a KiGGS Module), was performed by the Robert Koch Institute together with the division of nutrition and consumer education at the University of Paderborn. It was funded by the Federal Ministry of Food, Agriculture and Consumer Protection. Parents of participants younger than 12 years were asked to conduct a 3-day dietary record. Participants of 12 years and older were personally interviewed about their eating behaviour during the last four weeks using DISHES (Dietary Interview Software for Health Examination Studies). In addition, they were asked to fill in the KiGGS food frequency questionnaire a second time. Furthermore, all participants were asked about their socio-demographic background, leisure time activities, supplement use, meals at school, body weight and height. The study will provide up-to-date, representative data on the nutrition of children and adolescents in Germany. The analyses will include the amounts of foods and food groups consumed as well as the nutrient intake. By connecting these nutrition data with other health data from KiGGS, comprehensive analyses of relationships between nutrition and health are possible.

Physicochemical evaluation of PLA nanoparticles stabilized by water-soluble MPEO-PLA block copolymers.

Different water-soluble MPEO-PLA diblock copolymers with various alpha-methoxy-omega-hydroxyl polyethylene (MPEO) and poly(lactic acid) (PLA) block lengths have been synthesized. Their surface-active properties were evidenced by surface tension (water/air) measurements. In each case the surface tension leveled down above a critical polymer concentration, which was attributed to the formation of a dense polymer layer at the liquid-air interface. The applicability of copolymers as emulsion stabilizers in the preparation of PLA nanospheres by an o/w emulsion/evaporation technique was then investigated. Four copolymers presenting sufficient water solubility and good surfactive properties were used to prepare PLA nanospheres with MPEO chains firmly anchored at the particle surface. The effect of polymer concentration in emulsion on particle size and surface coverage was examined. Whatever the copolymer characteristics, it was found that the optimal concentration to obtain a large amount of MPEO at the particle surface was similar (around 2 g/l). The effect of the copolymer composition on MPEO layer characteristics and on colloidal stability was also evaluated. The conformation of MPEO blocks at the PLA particle surface is discussed in relation to the layer thickness and the surface area occupied per molecule.

Transcriptional regulation of the SMK1 mitogen-activated protein kinase gene during meiotic development in Saccharomyces cerevisiae.

Meiotic development (sporulation) in Saccharomyces cerevisiae is characterized by an ordered pattern of gene expression, with sporulation-specific genes classified as early, middle, mid-late, or late depending on when they are expressed. SMK1 encodes a mitogen-activated protein kinase required for spore morphogenesis that is expressed as a middle sporulation-specific gene. Here, we identify the cis-acting DNA elements that regulate SMK1 transcription and characterize the phenotypes of mutants with altered expression patterns. The SMK1 promoter contains an upstream activating sequence (UASS) that specifically interacts with the transcriptional activator Abf1p. The Abf1p-binding sites from the early HOP1 and the middle SMK1 promoters are functionally interchangeable, demonstrating that these elements do not play a direct role in their differential transcriptional timing. Timing of SMK1 expression is determined by another cis-acting DNA sequence termed MSE (for middle sporulation element). The MSE is required not only for activation of SMK1 transcription during middle sporulation but also for its repression during vegetative growth and early meiosis. In addition, the SMK1 MSE can repress vegetative expression in the context of the HOP1 promoter and convert HOP1 from an early to a middle gene. SMK1 function is not contingent on its tight transcriptional regulation as a middle sporulation-specific gene. However, promoter mutants with different quantitative defects in SMK1 transcript levels during middle sporulation show distinct sporulation phenotypes.

Localization of the laminin alpha 2 chain in normal human skeletal muscle and peripheral nerve: an ultrastructural immunolabeling study.

A particular form of congenital muscular dystrophy is associated with a deficiency of the tissue-specific basement membrane protein laminin alpha 2. A more precise knowledge of the normal distribution and localization of laminin alpha 2 would be useful in further elucidating the development of this disorder. In this study we used specific electron microscopic techniques, i.e., thin-section fracture labeling and cryoultramicrotomy in combination with immunogold labeling for laminin alpha 2, to determine its ultrastructural localization in normal human muscle and peripheral nerve. Both in muscle and in peripheral nerve, laminin alpha 2 is found to be associated solely with the basal lamina of myofibers and Schwann cells, respectively. Of special interest is the finding that in peripheral nerve, laminin alpha 2 is associated only with myelinated and not with unmyelinated nerve fibers.

Localization of laminin alpha 2 chain in normal human central nervous system: an immunofluorescence and ultrastructural study.

Recently, a rare form of congenital muscular dystrophy has been shown to be associated with a deficiency of laminin alpha 2 chain, a tissue-specific component of the basal lamina. Besides muscular dystrophy, children affected with this disorder also show electrophysiological and magnetic resonance imaging evidence of white matter involvement in the central nervous system (CNS). We have studied the precise localization of laminin alpha 2 chain in normal human brain, using specific electron microscopic techniques including thin-section fracture labeling and cryoultramicrotomy, in parallel with immunohistochemical techniques. We found that this laminin chain was localized to the basal lamina of all cerebral blood vessels, whereas blood vessels of the choroid plexus did not show any reaction. No positive reaction was found in meningeal blood vessels either. We hypothesize that in normal brain, laminin alpha 2 may be important for the selective filtration capability of the blood-brain barrier. The lack of laminin alpha 2 in cerebral vessels of children with laminin alpha 2-deficient congenital muscular dystrophy may cause impaired selective filtration, leading to leakage of plasma components and damage to the CNS. Further studies should be performed on patients affected by congenital muscular dystrophy associated with laminin alpha 2 deficiency to test this hypothesis.

Muscular dystrophy, mental retardation and cardiomyopathy not associated with dystrophin deficiency.

We report on a male patient aged 38, affected by a syndrome whose characteristic features include onset in early childhood, slow progression, diffuse muscle weakness, mental retardation and cardiomyopathy. Muscle biopsy showed myopathic changes compatible with muscular dystrophy. However, immunostaining for dystrophin as well as 50 and 43 kDa dystrophin-associated glycoproteins (DAGs) was normal. Genetic analysis suggested that direct involvement of the dystrophin gene was highly unlikely. No other family members were affected. Although the clinical picture is reminiscent of Duchenne/Becker muscular dystrophy, the immunologically and genetically documented lack of dystrophin involvement suggests that this particular syndrome is as yet undescribed.

Localization of merosin in the normal human brain: implications for congenital muscular dystrophy with merosin deficiency.

A particular form of congenital muscular dystrophy with merosin deficiency has recently been described. Magnetic resonance imaging has shown that affected children show brain abnormalities. We investigate the localization of merosin in the normal human brain by immunohistochemistry. Other organs, such as the kidney, lung and liver, were also included in this study. We show that in the normal central nervous system merosin is localized in the basement membrane of blood vessels. No expression of merosin was found at the level of the liver and lungs, whereas the glomerular mesangial matrix of the kidney was intensely positive. These results suggest that merosin deficiency in the basement membrane of blood vessels in the central nervous system could play an important role in the physiopathology of brain abnormalities found in children affected by the congenital muscular dystrophy associated with merosin deficiency. Furthermore, the potential absence of merosin in the glomerular mesangial matrix of the kidney suggests a multi-system involvement.

Microtubule-associated protein tau epitopes are present in fiber lesions in diverse muscle disorders.

The microtubule-associated protein tau is a major cytoskeletal protein involved in the neurofibrillary tangles of Alzheimer's disease. Although tau is predominantly a neuronal protein, it has been demonstrated in glia and other nonneuronal cells. We describe the presence of microtubule-associated protein tau epitopes in various muscle fiber lesions in oculopharyngeal and Becker muscular dystrophy, dermatomyositis, central core disease, neurogenic atrophy, and in the recovery phase of an attack of malignant hyperthermia. Western blot demonstrated a 100- to 110-kd tau-immunoreactive protein probably corresponding to 'big tau' as described in peripheral nerves. Tau immunoreactivity in muscle fiber lesions usually co-localized with tubulin, although electron microscopy failed to show an increase in microtubules. Tau and tubulin reactivity also correlated with the presence of desmin and vimentin epitopes. Possible explanations for the presence of tau are briefly discussed.

Detection of tau proteins in normal and Alzheimer's disease cerebrospinal fluid with a sensitive sandwich enzyme-linked immunosorbent assay.

Alzheimer's disease is a progressive degenerative dementia characterized by the abundant presence of neurofibrillary tangles in neurons. This study was designed to test whether the microtubule-associated protein tau, a major component of neurofibrillary tangles, could be detected in CSF. Additionally, we investigated whether CSF tau levels were abnormal in Alzheimer's disease as compared with a large group of control patients. We developed a sensitive sandwich enzyme-linked immunosorbent assay using AT120, a monoclonal antibody directed to human tau, as a capturing antibody. With this technique, the detection limit for tau was less than 5 pg/ml of CSF. Using AT8, which recognizes abnormally phosphorylated serines 199-202 in tau, the detection limit was below 20 pg/ml of CSF. However, with AT8, we found no immunoreactivity in CSF, suggesting that only a small fraction of CSF tau contains the abnormally phosphorylated AT8 epitope. Our results indicate that CSF tau levels are significantly increased in Alzheimer's disease. Also, CSF tau levels in a large group of patients with a diversity of neurological diseases showed overlap with CSF tau levels in Alzheimer's disease.

The abnormal phosphorylation of tau protein at Ser-202 in Alzheimer disease recapitulates phosphorylation during development.

Tau is a neuronal phosphoprotein whose expression is developmentally regulated. A single tau isoform is expressed in fetal human brain but six isoforms are expressed in adult brain, with the fetal isoform corresponding to the shortest of the adult isoforms. Phosphorylation of tau is also developmentally regulated, as fetal tau is phosphorylated at more sites than adult tau. In Alzheimer disease, the six adult tau isoforms become abnormally phosphorylated and form the paired helical filament, the major fibrous component of the characteristic neurofibrillary lesions. We show here that Ser-202 (in the numbering of the longest human brain tau isoform) is a phosphorylation site that distinguishes fetal from adult tau and we identify it as one of the abnormal phosphorylation sites in Alzheimer disease. The abnormal phosphorylation of tau at Ser-202 in Alzheimer disease thus recapitulates normal phosphorylation during development.