Multiscale and multimodal spectral Imaging for mapping cell wall polymers in plant organs

Multiscale and Multimodal Spectral Imaging for Mapping Cell Wall Polymers in Plant Organs. 2nd International Plant Spectroscopy Conferenc

Synthesis of molecularly imprinted polymer for glucose binding

Molecularly imprinted polymer (MIP) is an attractive technique for the synthesis of highly selective polymeric receptors having artificial generated recognition sites. These materials were synthesized with polymerizable functional monomers and crosslinker that were surrounded around the template molecule. After polymerization, a template molecule was removed leaving in the polymer selective recognition sites with shape, size and functionalities complementary to the template. This study presents a synthesis of MIP selectively for glucose binding. Glucose phosphate salt (GPS) was used as a template molecule with poly(allylamine hydrochloride) (PAA.HCl) as a functional monomer. Three types of crosslinkers which are epichlorohydrin (EPI), ethylene glycol diglycidyl ether (EDGE) and glycerol diglycidyl ether (GDE) were studied during the MIP synthesis. MIP prepared using EPI as a crosslinking showed the highest glucose binding capacity around 0.84 mg glucose/mg dried gel. The binding capacity of MIP prepared using EGDE and GDE are 0.78 mg glucose/mg gel and 0.38 mg glucose/mg gel respectively. It is also found that the increase on GPS monomer concentration will contribute to increase in glucose bindin

Autofluorescence multispectral image analysis at the macroscopic scale for tracking wheat grain tissues: a novel approach for a more specific identification of wheat grain dietary fibre

Wheat grain contains about 12-14% of fibres mainly located in the outer layers. The composition and the structure of wheat dietary fibres, as well as the nature and amount of co-passengers, vary according to the tissue where they are originated from. The aleurone layer is rich in low substituted arabinoxylans esterified to ferulic acid whereas outer pericarp contains highly substituted arabinoxylans but also cellulose and lignin. Consequently wheat dietary fibres properties showed a high variability according to their tissue of origin within the grain, which deeply impact their nutritional effects. If the identification of tissues in wheat grain is commonly performed, it remains challenging for food ingredient such as mill streams (flour, bran etc).Equipements are now available to acquire multispectral fluorescence images at the macroscopic scale using filters with specific excitation/emission wavelengths. These fluorescence macroscopes allow obtaining images of a representative number of particles together with a spatial resolution of less than 3 μm. In such images, the intensities measured for each pixel, though they are not spectra, can be assembled to form spectral profiles. To identify the tissular origin from this information, we propose to develop a prediction model on particles using calibration data coming from the observation of tissue sections. This approach is based on several assumptions. The first one is that the multispectral autofluorescence of plant tissues is specific and the second is that it is possible to measure fluorescence intensities in a reproducible way. The objective of the present work was to check the fluorescence macroscope as an efficient device for measuring and comparing fluorescence intensities.The variability of fluorescence profiles was studied by selecting pixels in cross-section or in particles mounted in air or in water. The statistical variations were studied by principal component analysis and variance analysis. The first effect, mainly described by principal component 1, was to differentiate aleurone layer from pericarp tissue. The second effect, mainly described by component 2, was a difference between the two mounting media. The differences between sections or powders were not correlated to the other factors and were considered as not significant. Our results show that profiles extracted from multispectral images of cross-sections or particles are similar and allow the identification of wheat grain tissues. If implemented, the prediction from cross-section could be less tedious than other methods requiring dissection and lead to the identification of more tissues. We have demonstrated the proof of concept of tracking wheat dietary fibre origin by predicting tissues on images of particles. This method could help to better qualify flours and various milling fractions as well as to control whole grain products

Contribution of image analysis to the description of enzymatic degradation kinetics for particulate food material

International audienceThe objective of the present work was to relate the physical evolution quantified by image analysis to the chemical transformation of beet pulp particles during enzymatic degradation. Beet pulps were degraded into a torus reactor equipped for visualisation. Pectinolytic and cellulolytic enzymes were used separately or in combination. Two global image analysis techniques were tested to characterise the size distribution of overlapping particles. Granulometric curves were extracted by mathematical morphology and a regularisation dimension was assessed by fractal analysis. Both techniques proved efficient to follow particle size evolution during degradation. When using cellulolytic enzymes alone, no chemical or physical evolution was observed. When using pectinolytic enzymes, a chemical modification occurred without any physical evolution. Particles physically disappeared when both enzymes were used. The chemical and physical evolutions of particles during degradation were interpreted taking into account the current model of molecular arrangement of primary cell walls

Combined approaches provide an anatomical and transcriptomic fingerprint of maize cell wall digestibility

Understanding cell wall biosynthesis and degradation in grasses has become a major aim in plant biology. Although independent previous reports have focused on specific features that dictate cell wall digestibility, cytological, biochemical, and gene regulation parameters have never been integrated within the same study. Herein, we applied a combination of state-of-the-art technologies and different scales of observation on two maize lines that are characterized by highly contrasted forage digestibility. Comparative image analysis of internode sections allow to get an anatomical fingerprint associated with high digestibility: a thin peripheral rind of lignified parenchyma, small numerous vascular bundles, and low proportion of PeriVascular Sclerenchyma (PVS). This cell type patterning led to enhanced digestibility when internode sections were treated with Celluclast, a commercially cell wall degrading enzyme. At a lower scale of observation, Laser Capture Microdissection (LCM) followed by thioacidolysis of PVS revealed a higher proportion of Syringyl (S) unit lignins in the low digestible line while the high digestible line was p-Hydroxyphenyl (H)-rich. Moreover, cytological observation of internodes of the two lines point out that this difference in composition is associated with a delayed lignification of PVS. At the same time, comparative transcriptomics on internodes indicated differential expression of several genes encoding enzymes along the phenylpropanoid pathway and known cell wall-associated Transcription Factors (TFs). Together, these results give an integrative view of different factors which could aim in designing a maize silage ideotype and provide a novel set of potential regulatory genes controlling lignification in maize

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Measurements of the Higgs boson production and decay rates and constraints on its couplings from a combined ATLAS and CMS analysis of the LHC pp collision data at root s=7 and 8 TeV

70 pages plus author lists + cover page (104 pages total), 32 figures, 22 tables, submitted to JHEP. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2015-07/ and at http://cms-results.web.cern.ch/cms-results/public-results/publications/HIG-15-002/Combined ATLAS and CMS measurements of the Higgs boson production and decay rates, as well as constraints on its couplings to vector bosons and fermions, are presented. The combination is based on the analysis of five production processes, namely gluon fusion, vector boson fusion, and associated production with a $W$ or a $Z$ boson or a pair of top quarks, and of the six decay modes $H \to ZZ, WW$, $\gamma\gamma, \tau\tau, bb$, and $\mu\mu$. All results are reported assuming a value of 125.09 GeV for the Higgs boson mass, the result of the combined measurement by the ATLAS and CMS experiments. The analysis uses the CERN LHC proton--proton collision data recorded by the ATLAS and CMS experiments in 2011 and 2012, corresponding to integrated luminosities per experiment of approximately 5 fb$^{-1}$ at $\sqrt{s}=7$ TeV and 20 fb$^{-1}$ at $\sqrt{s} = 8$ TeV. The Higgs boson production and decay rates measured by the two experiments are combined within the context of three generic parameterisations: two based on cross sections and branching fractions, and one on ratios of coupling modifiers. Several interpretations of the measurements with more model-dependent parameterisations are also given. The combined signal yield relative to the Standard Model prediction is measured to be 1.09 $\pm$ 0.11. The combined measurements lead to observed significances for the vector boson fusion production process and for the $H \to \tau\tau$ decay of $5.4$ and $5.5$ standard deviations, respectively. The data are consistent with the Standard Model predictions for all parameterisations considered.Peer reviewe