Morphogenesis at the inflorescence shoot apex of Anagallis arvensis: surface geometry and growth in comparison with the vegetative shoot

Quantitative analysis of geometry and surface growth based on the sequential replica method is used to compare morphogenesis at the shoot apex of Anagallis arvensis in the reproductive and vegetative phases of development. Formation of three types of lateral organs takes place at the Anagallis shoot apical meristem (SAM): vegetative leaf primordia are formed during the vegetative phase and leaf-like bracts and flower primordia during the reproductive phase. Although the shapes of all the three types of primordia are very similar during their early developmental stages, areal growth rates and anisotropy of apex surface growth accompanying formation of leaf or bract primordia are profoundly different from those during formation of flower primordia. This provides an example of different modes of de novo formation of a given shape. Moreover, growth accompanying the formation of the boundary between the SAM and flower primordium is entirely different from growth at the adaxial leaf or bract primordium boundary. In the latter, areal growth rates at the future boundary are the lowest of all the apex surface, while in the former they are relatively very high. The direction of maximal growth rate is latitudinal (along the future boundary) in the case of leaf or bract primordium but meridional (across the boundary) in the case of flower. The replica method does not enable direct analysis of growth in the direction perpendicular to the apex surface (anticlinal direction). Nevertheless, the reconstructed surfaces of consecutive replicas taken from an individual apex allow general directions of SAM surface bulging accompanying primordium formation to be recognized. Precise alignment of consecutive reconstructions shows that the direction of initial bulging during the leaf or bract formation is nearly parallel to the shoot axis (upward bulging), while in the case of flower it is perpendicular to the axis (lateral bulging). In future, such 3D reconstructions can be used to assess displacement velocity fields so that growth in the anticlinal direction can be assessed. In terms of self-perpetuation, the inflorescence SAM of Anagallis differs from the SAM in the vegetative phase in that the centrally located region of slow growth is less distinct in the inflorescence SAM. Moreover, the position of this slowly growing zone with respect to cells is not stable in the course of the meristem ontogeny

On knowledge and aesthetics: some learning experiences for a possible high school

El presente trabajo reporta parte de dos procesos de indagación sobre dos experiencias educativas: una escuela secundaria de la ciudad de Santa Fe y una propuesta lúdico–pedagógica dependiente del Ministerio de Innovación y Cultura de la Provincia de Santa Fe. Se consideran relevantes de ser estudiadas por los modos, disposiciones y decisiones que van desplegando con el sentido de habilitar prácticas de formación amplias. Ambas permiten pensar en la escuela secundaria desde recorridos inéditos que convocan sensibilidades, estéticas y saberes en procesos de subjetivación. Los dos estudios se sostienen en una perspectiva cualitativa en tanto se proponen comprender e interpretar la complejidad de sus objetos, antes que confirmar presupuestos y pretender explicaciones totalizantes. El artículo procura describir parte de la riqueza que implicaron estos recorridos. Para ello, una primera parte presenta el encuadre general y común que los vincula. Una segunda, describe particularidades, interrogantes y referentes categoriales centrales, así como los rasgos relevantes reportados en cada trabajo empírico. Finalmente, se comparten reflexiones construidas al calor de ambas experiencias de estudio, las que se proponen como posibles direcciones otras para la escuela secundaria.This paper reports part of two processes of inquiry about two educational experiences: a high school in the city of Santa Fe and a pedagogical proposal of the Ministry of Innovation and Culture of the Province of Santa Fe. They are considered relevant to be studied by the modes, dispositions and decisions that are deploying with the sense of enabling broad training practices. Both suggest the possibility of thinking in high school from unpublished tours that sensitivities, aesthetics and knowledge in processes of subjectivation. The two studies were held in a qualitative perspective as they intend to understand and interpret the complexity of their objects, rather than confirm budgets and claim totalizing. The article attempts to describe part of the wealth implied by these routes. To do this, the first part presents general and common frame which links them. A second one, describes particularities, questions and central categorical referents, as well as the relevant features reported in each empirical work. Finally, reflections built in the heat of both study experiences are shared, which are proposed as possible directions for the secondary school

Parasite Glycobiology:A Bittersweet Symphony

Human infections caused by parasitic protozoans and helminths are among the world's leading causes of death. More than a million people die each year from diseases like malaria and neglected tropical diseases like leishmaniasis, trypanosomiasis, and schistosomiasis. Patients also endure disabilities that cause lifelong suffering and that affect productivity and development [1]. More insidiously, parasites generate important economic losses, since they often also infect commercially valuable animals. Worldwide, exposure to parasites is increasing due to growing international travel and migrations, as well as climate changes, which affect the geographic distribution of the parasite vectors. The parasitic threat is also aggravated by the rise of the immunocompromised population, which is particularly sensitive to parasite infections (e.g., individuals with AIDS and other immunodeficiencies). A common feature of protozoan parasites and helminths is the synthesis of glycoconjugates and glycan-binding proteins for protection and to interact and respond to changes in their environment. To address the many challenges associated with the study of the structure, the biosynthesis, and the biology of parasitic glycans, the authors of this article have established GlycoPar, a European Marie Curie training program steered by some of the world's academic leaders in the field of parasite glycobiology, in close association with European industrial enterprises. The main scientific goal of this network is the description of novel paradigms and models by which parasite glycoconjugates play a role in the successful colonization of the different hosts. By means of a training-through-research program, the aim of the network is to contribute to the training of a generation of young scientists capable of tackling the challenges posed by parasite glycobiology

Prodromal neuroinflammatory, cholinergic and metabolite dysfunction detected by PET and MRS in the TgF344-AD transgenic rat model of AD: A collaborative multi-modal study

Mouse models of Alzheimer s disease (AD) are valuable but do not fully recapitulate human AD pathology, such as spontaneous Tau fibril accumulation and neuronal loss, necessitating the development of new AD models. The transgenic (TG) TgF344-AD rat has been reported to develop age-dependent AD features including neuronal loss and neurofibrillary tangles, despite only expressing APP and PSEN1 mutations, suggesting an improved modelling of AD hallmarks. Alterations in neuronal networks as well as learning performance and cognition tasks have been reported in this model, but none have combined a longitudinal, multimodal approach across multiple centres, which mimics the approaches commonly taken in clinical studies. We therefore aimed to further characterise the progression of AD-like pathology and cognition in the TgF344-AD rat from young-Adults (6 months (m)) to mid-(12 m) and advanced-stage (18 m, 25 m) of the disease. Methods: TgF344-AD rats and wild-Type (WT) littermates were imaged at 6 m, 12 m and 18 m with [18F]DPA-714 (TSPO, neuroinflammation), [18F]Florbetaben (A) and [18F]ASEM (7-nicotinic acetylcholine receptor) and with magnetic resonance spectroscopy (MRS) and with (S)-[18F]THK5117 (Tau) at 15 and 25 m. Behaviour tests were also performed at 6 m, 12 m and 18 m. Immunohistochemistry (CD11b, GFAP, A, NeuN, NeuroChrom) and Tau (S)-[18F]THK5117 autoradiography, immunohistochemistry and Western blot were also performed. Results: [18F]DPA-714 positron emission tomography (PET) showed an increase in neuroinflammation in TG vs wildtype animals from 12 m in the hippocampus (+11%), and at the advanced-stage AD in the hippocampus (+12%), the thalamus (+11%) and frontal cortex (+14%). This finding coincided with strong increases in brain microgliosis (CD11b) and astrogliosis (GFAP) at these time-points as assessed by immunohistochemistry. In vivo [18F]ASEM PET revealed an age-dependent increase uptake in the striatum and pallidum/nucleus basalis of Meynert in WT only, similar to that observed with this tracer in humans, resulting in TG being significantly lower than WT by 18 m. In vivo [18F]Florbetaben PET scanning detected A accumulation at 18 m, and (S)-[18F]THK5117 PET revealed subsequent Tau accumulation at 25m in hippocampal and cortical regions. A plaques were low but detectable by immunohistochemistry from 6 m, increasing further at 12 and 18 m with Tau-positive neurons adjacent to A plaques at 18 m. NeuroChrom (a pan neuronal marker) immunohistochemistry revealed a loss of neuronal staining at the A plaques locations, while NeuN labelling revealed an age-dependent decrease in hippocampal neuron number in both genotypes. Behavioural assessment using the novel object recognition task revealed that both WT & TgF344-AD animals discriminated the novel from familiar object at 3 m and 6 m of age. However, low levels of exploration observed in both genotypes at later time-points resulted in neither genotype successfully completing the task. Deficits in social interaction were only observed at 3 m in the TgF344-AD animals. By in vivo MRS, we showed a decrease in neuronal marker N-Acetyl-Aspartate in the hippocampus at 18 m (-18% vs age-matched WT, and-31% vs 6 m TG) and increased Taurine in the cortex of TG (+35% vs age-matched WT, and +55% vs 6 m TG). Conclusions: This multi-centre multi-modal study demonstrates, for the first time, alterations in brain metabolites, cholinergic receptors and neuroinflammation in vivo in this model, validated by robust ex vivo approaches. Our data confirm that, unlike mouse models, the TgF344-AD express Tau pathology that can be detected via PET, albeit later than by ex vivo techniques, and is a useful model to assess and longitudinally monitor early neurotransmission dysfunction and neuroinflammation in AD

Neurite density is reduced in the presymptomatic phase of C9orf72 disease

OBJECTIVE: To assess the added value of neurite orientation dispersion and density imaging (NODDI) compared with conventional diffusion tensor imaging (DTI) and anatomical MRI to detect changes in presymptomatic carriers of chromosome 9 open reading frame 72 (C9orf72) mutation. METHODS: The PREV-DEMALS (Predict to Prevent Frontotemporal Lobar Degeneration and Amyotrophic Lateral Sclerosis) study is a prospective, multicentre, observational study of first-degree relatives of individuals carrying the C9orf72 mutation. Sixty-seven participants (38 presymptomatic C9orf72 mutation carriers (C9+) and 29 non-carriers (C9-)) were included in the present cross-sectional study. Each participant underwent one single-shell, multishell diffusion MRI and three-dimensional T1-weighted MRI. Volumetric measures, DTI and NODDI metrics were calculated within regions of interest. Differences in white matter integrity, grey matter volume and free water fraction between C9+ and C9- individuals were assessed using linear mixed-effects models. RESULTS: Compared with C9-, C9+ demonstrated white matter abnormalities in 10 tracts with neurite density index and only 5 tracts with DTI metrics. Effect size was significantly higher for the neurite density index than for DTI metrics in two tracts. No tract had a significantly higher effect size for DTI than for NODDI. For grey matter cortical analysis, free water fraction was increased in 13 regions in C9+, whereas 11 regions displayed volumetric atrophy. CONCLUSIONS: NODDI provides higher sensitivity and greater tissue specificity compared with conventional DTI for identifying white matter abnormalities in the presymptomatic C9orf72 carriers. Our results encourage the use of neurite density as a biomarker of the preclinical phase. TRIAL REGISTRATION NUMBER: NCT02590276

Glycans in Sera of Amyotrophic Lateral Sclerosis Patients and Their Role in Killing Neuronal Cells

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease caused by degeneration of upper and lower motor neurons. To date, glycosylation patterns of glycoproteins in fluids of ALS patients have not been described. Moreover, the aberrant glycosylation related to the pathogenesis of other neurodegenerative diseases encouraged us to explore the glycome of ALS patient sera. We found high levels of sialylated glycans and low levels of core fucosylated glycans in serum-derived N-glycans of patients with ALS, compared to healthy volunteer sera. Based on these results, we analyzed the IgG Fc N297-glycans, as IgG are major serum glycoproteins affected by sialylation or core fucosylation and are found in the motor cortex of ALS patients. The analyses revealed a distinct glycan, A2BG2, in IgG derived from ALS patient sera (ALS-IgG). This glycan increases the affinity of IgG to CD16 on effector cells, consequently enhancing Antibody-Dependent Cellular Cytotoxicity (ADCC). Therefore, we explore whether the Fc-N297-glycans of IgG may be involved in ALS disease. Immunostaining of brain and spinal cord tissues revealed over-expression of CD16 and co-localization of intact ALS-IgG with CD16 and in brain with activated microglia of G93A-SOD1 mice. Intact ALS-IgG enhanced effector cell activation and ADCC reaction in comparison to sugar-depleted or control IgG. ALS-IgG were localized in the synapse between brain microglia and neurons of G93A-SOD1 mice, manifesting a promising in vivo ADCC reaction. Therefore, glycans of ALS-IgG may serve as a biomarker for the disease and may be involved in neuronal damage

Technology generation to dissemination:lessons learned from the tef improvement project

Indigenous crops also known as orphan crops are key contributors to food security, which is becoming increasingly vulnerable with the current trend of population growth and climate change. They have the major advantage that they fit well into the general socio-economic and ecological context of developing world agriculture. However, most indigenous crops did not benefit from the Green Revolution, which dramatically increased the yield of major crops such as wheat and rice. Here, we describe the Tef Improvement Project, which employs both conventional- and molecular-breeding techniques to improve tef\u2014an orphan crop important to the food security in the Horn of Africa, a region of the world with recurring devastating famines. We have established an efficient pipeline to bring improved tef lines from the laboratory to the farmers of Ethiopia. Of critical importance to the long-term success of this project is the cooperation among participants in Ethiopia and Switzerland, including donors, policy makers, research institutions, and farmers. Together, European and African scientists have developed a pipeline using breeding and genomic tools to improve the orphan crop tef and bring new cultivars to the farmers in Ethiopia. We highlight a new variety, Tesfa, developed in this pipeline and possessing a novel and desirable combination of traits. Tesfa\u2019s recent approval for release illustrates the success of the project and marks a milestone as it is the first variety (of many in the pipeline) to be released

A nanostructural view of the cell wall disassembly process during fruit ripening and postharvest storage by atomic force microscopy

Background: The mechanical properties of parenchyma cell walls and the strength and extension of adhesion areas between adjacent cells, jointly with cell turgor, are main determinants of firmness of fleshy fruits. These traits are modified during ripening leading to fruit softening. Cell wall modifications involve the depolymerisation of matrix glycans and pectins, the solubilisation of pectins and the loss of neutral sugars from pectin side chains. These changes weaken the cell walls and increase cell separation, which in combination with a reduction in cell turgor, bring about textural changes. Atomic force microscopy (AFM) has been used to characterize the nanostructure of cell wall polysaccharides during the ripening and postharvest storage of several fruits. This technique allows the imaging of individual polymers at high magnification with minimal sample preparation. Scope and approach: This paper reviews the main features of the cell wall disassembly process associated to fruit softening from a nanostructural point of view, as has been provided by AFM studies. Key findings and conclusions: AFM studies show that pectin size, ramification and complexity is reduced during fruit ripening and storage, and in most cases these changes correlate with softening. Postharvest treatments that improve fruit quality have been proven to preserve pectin structure, suggesting a clear link between softening and pectin metabolism. Nanostructural characterization of cellulose and hemicellulose during ripening has been poorly explored by AFM and the scarce results available are not conclusive. Globally, AFM could be a powerful tool to gain insights about the bases of textural fruit quality in fresh and stored fruits

Contextualizing students' alcohol use perceptions and practices within French culture: an analysis of gender and drinking among sport-science college students

Although research has examined alcohol consumption and sport in a variety of contexts, there is a paucity of research on gender and gender dynamics among French college students. The present study addresses this gap in the literature by examining alcohol use practices by men and women among a non-probability sample of French sport science students from five different universities in Northern France. We utilized both survey data (N = 534) and in-depth qualitative interviews (n = 16) to provide empirical and theoretical insight into a relatively ubiquitous health concern: the culture of intoxication. Qualitative data were based on students’ perceptions of their own alcohol use; analysis were framed by theoretical conceptions of gender. Survey results indicate gender differences in alcohol consumption wherein men reported a substantially higher frequency and quantity of alcohol use compared to their female peers. Qualitative findings confirm that male privilege and women’s concern for safety, masculine embodiment via alcohol use, gendering of alcohol type, and gender conformity pressures shape gender disparities in alcohol use behavior. Our findings also suggest that health education policy and educational programs focused on alcohol-related health risks need to be designed to take into account gender category and gender orientation