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Platelets, Thrombo-Inflammation, and Cancer: Collaborating With the Enemy
No full textPlatelets are small anucleate cells present in the blood stream, their typical role in primary hemostasis has been well-described. However, new evidence suggests that they have critically important roles in cancer progression and inflammation. Cancer cells can activate platelets, thus using them as physical shields from blood shear forces and natural killer (NK) cells. The activated platelets may also regulate hematopoietic and immune cell migration toward the tumor site; therefore, contributing to the cancer-associated inflammation. The activation of platelets by cancer cells may also contribute to metastasis and cancer progression by stimulating deep venous thrombosis and neutrophil extracellular trap formations (NETs) that "hide" cancer cells. We strived to review the current literature to dissect the role of platelets in cancer-associated thrombosis and tumor microenvironment inflammation
Insect pollination is an ecological process involved in the assembly of the seed microbiota
No full textThe assembly of the seed microbiota involves some early microbial seed colonizers that are transmitted from the maternal plant through the vascular system, while other microbes enter through the stigma. Thus, the seed microbiota consists of microbes not only recruited from the vascular tissues of the plant, but also from the flower. Flowers are known to be a hub for microbial transmission between plants and insects. This floral-insect exchange opens the possibility for insect-transmitted bacteria to colonize the ovule and subsequently the seed, and to pass then into the next plant generation. In this study, we evaluated the contribution of insect pollination to the seed microbiota through high-throughput sequencing. Oilseed rape (OSR) Brassica napus flowers were exposed to visits and pollination by honey bees (Apis mellifera) or red mason bees (Osmia bicornis), hand pollination, or autonomous self-pollination (ASP). Sequence analyses revealed that honey bee visitation reduced the bacterial richness and diversity, increased the variability in the seed microbial structure, and introduced bee-associated taxa. In contrast, mason bee pollination had minor effects on the seed microbiota. We highlight the need to consider insect pollination as an ecological process involved in the transmission of bacteria from flower to seeds
Accounting for Wood, Foliage Properties, and Laser Effective Footprint in Estimations of Leaf Area Density from Multiview-LiDAR Data
No full textThe spatial distribution of Leaf Area Density (LAD) in a tree canopy has fundamental functions in ecosystems. It can be measured through a variety of methods, including voxel-based methods applied to LiDAR point clouds. A theoretical study recently compared the numerical errors of these methods and showed that the bias-corrected Maximum Likelihood Estimator was the most efficient. However, it ignored (i) wood volumes, (ii) vegetation sub-grid clumping, (iii) the instrument effective footprint, and (iv) was limited to a single viewpoint. In practice, retrieving LAD is not straightforward, because vegetation is not randomly distributed in sub-grids, beams are divergent, and forestry plots are sampled from more than one viewpoint to mitigate occlusion. In the present article, we extend the previous formulation to (i) account for both wood volumes and hits, (ii) rigorously include correction terms for vegetation and instrument characteristics, and (iii) integrate multiview data. Two numerical experiments showed that the new approach entailed reduction of bias and errors, especially in the presence of wood volumes or when multiview data are available for poorly-explored volumes. In addition to its conciseness, completeness, and efficiency, this new formulation can be applied to multiview TLS—and also potentially to UAV LiDAR scanning—to reduce errors in LAD estimation
Correction to: Amaryllidaceae alkaloids: identification and partial characterization of montanine production in Rhodophiala bifida plant
No full textThe glycoproteins EDIL3 and MFGE8 regulate vesicle - mediated eggshell calcification in a new model for avian biomineralisation
No full textEffects of leaf length and development stage on the triple oxygen isotope signature of grass leaf water and phytoliths: insights for a proxy of continental atmospheric humidity
No full textContinental relative humidity (RH) is a key climate parameter, but there is a lack of quantitative RH proxies suitable for climate model-data comparisons. Recently, a combination of climate chamber and natural transect calibrations have laid the groundwork for examining the robustness of the triple oxygen isotope composition (delta O-'18 and O-17-excess) of phytoliths, that can preserve in sediments, as a new proxy for past changes in RH. However, it was recommended that besides RH, additional factors that may impact delta'O-18 and O-17-excess of plant water and phytoliths be examined. Here, the effects of grass leaf length, leaf development stage and day-night alternations are addressed from growth chamber experiments. The triple oxygen isotope compositions of leaf water and phytoliths of the grass species F. arundinacea are analysed. Evolution of the leaf water delta'O-18 and O-17-excess along the leaf length can be modelled using a string-of-lakes approach to which an unevaporated-evaporated mixing equation must be added. We show that for phytoliths to record this evolution, a kinetic fractionation between leaf water and silica, increasing from the base to the apex, must be assumed. Despite the isotope heterogeneity of leaf water along the leaf length, the bulk leaf phytolith delta'O-18 and O-17-excess values can be estimated from the Craig and Gordon model and a mean leaf water-phytolith fractionation exponent (lambda(Phyto-LW)) of 0.521. In addition to not being leaf length dependent, delta'O-18 and O-17-excess of grass phytoliths are expected to be impacted only very slightly by the stem vs. leaf biomass ratio. Our experiment additionally shows that because a lot of silica polymerises in grasses when the leaf reaches senescence (58 % of leaf phytoliths in mass), RH prevailing during the start of senescence should be considered in addition to RH prevailing during leaf growth when interpreting the O-17-excess of grass bulk phytoliths. Although under the study conditions O-17-excess(Phyto) do not vary significantly from constant day to day-night conditions, additional monitoring at low RH conditions should be done before drawing any generalisable conclusions. Overall, this study strengthens the reliability of the O-17-excess of phytoliths to be used as a proxy of RH. If future studies show that the mean value of 0.521 used for the grass leaf water-phytolith fractionation exponent lambda(Phyto-LW) is not climate dependent, then grassland leaf water O-17-excess obtained from grassland phytolith O-17-excess would inform on isotope signals of several soil-plant-atmosphere processes
WUSCHEL acts as an auxin response rheostat to maintain apical stem cells in Arabidopsis
No full textTo maintain the balance between long-term stem cell self-renewal and differentiation, dynamic signals need to be translated into spatially precise and temporally stable gene expression states. In the apical plant stem cell system, local accumulation of the small, highly mobile phytohormone auxin triggers differentiation while at the same time, pluripotent stem cells are maintained throughout the entire life-cycle. We find that stem cells are resistant to auxin mediated differentiation, but require low levels of signaling for their maintenance. We demonstrate that the WUSCHEL transcription factor confers this behavior by rheostatically controlling the auxin signaling and response pathway. Finally, we show that WUSCHEL acts via regulation of histone acetylation at target loci, including those with functions in the auxin pathway. Our results reveal an important mechanism that allows cells to differentially translate a potent and highly dynamic developmental signal into stable cell behavior with high spatial precision and temporal robustness
Analysis and Modeling of the Variations of Root Branching Density Within Individual Plants and Among Species
No full textBranching density (or the reciprocal: inter-branch distance) is an important trait which contributes to defining the number of roots in individual plants. The environmental and local variations in inter-branch distance have often been stressed, and simulations models have been put forward to take them into account within the dynamics of root system architecture (RSA). However, little is known about the interspecific and intraplant variations of inter-branch distance. In this paper, we present an analysis which draws on 40 samples of plants belonging to 36 species collected in homogeneous soils, to address how the variations in inter-branch distance are structured within individual plants, and how this structure varies from one species to another. Using measurements of inter-branch distance on various roots of the same species and our knowledge of the branching process, we defined a simple and generic model dedicated to the simulation of the observed variations. This model distinguishes between two sub-processes: i) the longitudinal location of potential branching sites and ii) the effective emergence of lateral roots at these sites. Thus, it represents the variations in distance between the potential sites (with two parameters), and the probability of emergence of a lateral root at each site (one parameter). We show the ability of this model to account for the main variations in inter-branch distances with a limited number of parameters, and we estimated them for the different species. These parameters can be considered as promising traits to characterize-in a comprehensive and simple way-the genetic and environmental variations in the whole branching process at plant level. Based on the results, we make recommendations for carrying out comparable measurements of the branching density in developed plants. Moreover, we suggest the integration of this new model as a module in future RSA simulators, to improve their capacity to account for this important and highly variable characteristic of plant species
From UK land-bridge to sea route: Irish agri-food exports to the EU, transport modes and Brexit
No full textFrom UK land-bridge to sea route: Irish agri-food exports to the EU, transport modes and Brexi
SGC Bretagne - Expérimenter et évaluer des systèmes de grandes cultures économes en intrants phytosanitaires (de l’intégré au biologique).
No full textDans le cadre du projet « SGC Bretagne », trois systèmes de culture innovants, sans culture fourragère
pluriannuelle et conçus pour répondre aux besoins des filières d’élevage, ont été conduits durant 6 ans
et évalués. La conception de ces trois systèmes s’est appuyée sur le cadre « ESR – Efficience,
Substitution, Re-conception» : deux systèmes conventionnels s’appuyaient l’un sur la recherche
d’efficience dans l’utilisation des produits phytosanitaires, l’autre sur les méthodes de reconception des
systèmes de culture ; le troisième était en agriculture biologique. L’évaluation pluri-critères de ces
systèmes de culture met en évidence la possibilité de diminuer le recours aux produits phytosanitaires
tout en maintenant la rentabilité et sans augmenter la charge de travail. Les systèmes de culture testés
ne pénalisent pas les marges semi-nettes par rapport à la référence utilisée : elles sont équivalentes ou
meilleures. La diminution de l’IFT est proche de l’objectif fixé à -50%, avec une réduction de 44% pour
les systèmes ayant recours aux produits phytosanitaires, limitée par la dépendance aux herbicides pour
la maîtrise des vivaces en interculture. Un autre résultat de l’expérimentation est que la diversification
des systèmes de culture limite les variations économiques entre années, avec des compensations qui
se font d’une culture à l’autre au sein de l’assolement.As part of the "SGC Bretagne" project, three innovative cropping systems, including no forage crops and
designed to meet the needs of cattle breeding, were experimented for 5 years and evaluated. The
design of these three systems was based on the "ESR - Efficiency, Substitution, Re-design" framework:
two conventional systems were based, one on the search for efficiency in the use of phytosanitary
products, the other on the methods of cropping systems re-design; the third was designed according to
organic farming principles. The evaluation of these cropping systems highlights the possibility of
reducing the use of phytosanitary products while maintaining profitability and workload. The cropping
systems evaluated did not penalize the semi-net margins compared to the reference used: they are
equivalent or better. The decrease in IFT is close to the target of -50%, with a reduction of 44% for
systems using phytosanitary products, limited by herbicide dependence for the control of perennials in
intercropping. Another result of the experiment is that the diversification of cropping systems limits
economic variations between years, thanks to offsets from one crop to another within the rotation