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

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

Physicochemical and Structural Properties of Starch Isolated from Fresh and Dried Chestnuts and Chestnut Flour

U radu su određeni sljedeći parametri: raspodjela veličine čestica, boja, morfologija i kemijski sastav škroba dobivenog iz svježih plodova kestena (Castanea sativa Mill.), plodova prosušenih na sobnoj temperaturi, te iz kupovnog kestenovog brašna. Raspodjela je veličina čestica u sve tri vrste škroba bila bimodalna, pa su u škrobu iz svježeg kestena opažene dvije veličine zrnaca, i to mala (promjera od 1,5 μm) i velika zrnca (10,5 μm). Veličina je zrnaca škroba ovisila o udjelu vlage u uzorcima. Najveća su zrnca opažena u škrobu iz svježeg kestena, a najmanja u onom iz kupovnog brašna, međutim, morfološke značajke zrnaca nisu bile bitno različite. Većina je zrnaca imala okrugli ili ovalni oblik, a samo su poneka bila trolisnog oblika, što nije uobičajeno u drugim vrstama škroba. Uzorci su škroba iz kupovnog brašna imali najtamniju, a uzorak iz svježih plodova kestena najsvijetliju boju. Ukupan se udjel škroba u ispitanim uzorcima bitno razlikovao, a izolacija je škroba iz sušenih plodova kestena bila uspješnija. U svim je uzorcima bilo malo oštećenih zrnaca škroba (<2,91 %), a maseni je udjel amiloze bio srednje velik (od 17,0 do 25,8 % na bazi suhe tvari). Najmanji je udjel amiloze pronađen u škrobu iz svježih plodova kestena, iako još uvijek unutar vrijednosti ostalih uobičajenih vrsta škrobova.Particle size distribution, colour, morphology and chemical composition of chestnut (Castanea sativa Mill.) starches isolated from fresh chestnut fruits (S1), semi-dried chestnut fruits at room temperature (S2) and commercial chestnut flour (S3) were determined using several experimental techniques. All starches had a bimodal particle size distribution, particularly S1 showed two types of starch granules – small (1.5 μm diameter) and large granules (10.5 μm). Starch granule sizes depended on the moisture content of the samples, decreasing slightly in the following order S1>S2>S3; however, no significant differences were observed in the morphological analysis. Most of the granules exhibited round or oval shapes, and exceptionally, some of them featured trefoil shape, which is not usually found in other starches. Colour results indicated that S3 samples had the darkest colour, followed by S2 and S1. Tested chestnut starches showed significant differences in total starch content, with starch isolation being more selective in dried samples. All samples showed low damaged starch (<2.91 %) and intermediate amylose (from 17.0 to 25.8 %) content on dry mass basis. The lowest amount of amylose was obtained in S1, even though it was within the range of common commercial starches

Competition and moral behavior: A meta-analysis of forty-five crowd-sourced experimental designs

Does competition affect moral behavior? This fundamental question has been debated among leading scholars for centuries, and more recently, it has been tested in experimental studies yielding a body of rather inconclusive empirical evidence. A potential source of ambivalent empirical results on the same hypothesis is design heterogeneity—variation in true effect sizes across various reasonable experimental research protocols. To provide further evidence on whether competition affects moral behavior and to examine whether the generalizability of a single experimental study is jeopardized by design heterogeneity, we invited independent research teams to contribute experimental designs to a crowd-sourced project. In a large-scale online data collection, 18,123 experimental participants were randomly allocated to 45 randomly selected experimental designs out of 95 submitted designs. We find a small adverse effect of competition on moral behavior in a meta-analysis of the pooled data. The crowd-sourced design of our study allows for a clean identification and estimation of the variation in effect sizes above and beyond what could be expected due to sampling variance. We find substantial design heterogeneity—estimated to be about 1.6 times as large as the average standard error of effect size estimates of the 45 research designs—indicating that the informativeness and generalizability of results based on a single experimental design are limited. Drawing strong conclusions about the underlying hypotheses in the presence of substantive design heterogeneity requires moving toward much larger data collections on various experimental designs testing the same hypothesis

Transmissibility of Atypical Scrapie in Ovine Transgenic Mice: Major Effects of Host Prion Protein Expression and Donor Prion Genotype

Atypical scrapie or Nor98 has been identified as a transmissible spongiform encephalopathy (TSE) that is clearly distinguishable from classical scrapie and BSE, notably regarding the biochemical features of the protease-resistant prion protein PrPres and the genetic factors involved in susceptibility to the disease. In this study we transmitted the disease from a series of 12 French atypical scrapie isolates in a transgenic mouse model (TgOvPrP4) overexpressing in the brain ∼0.25, 1.5 or 6× the levels of the PrPARQ ovine prion protein under the control of the neuron-specific enolase promoter. We used an approach based on serum PrPc measurements that appeared to reflect the different PrPc expression levels in the central nervous system. We found that transmission of atypical scrapie, much more than in classical scrapie or BSE, was strongly influenced by the PrPc expression levels of TgOvPrP4 inoculated mice. Whereas TgOvPrP4 mice overexpressing ∼6× the normal PrPc level died after a survival periods of 400 days, those with ∼1.5× the normal PrPc level died at around 700 days. The transmission of atypical scrapie in TgOvPrP4 mouse line was also strongly influenced by the prnp genotypes of the animal source of atypical scrapie. Isolates carrying the AF141RQ or AHQ alleles, associated with increased disease susceptibility in the natural host, showed a higher transmissibility in TgOvPrP4 mice. The biochemical analysis of PrPres in TgOvPrP4 mouse brains showed a fully conserved pattern, compared to that in the natural host, with three distinct PrPres products. Our results throw light on the transmission features of atypical scrapie and suggest that the risk of transmission is intrinsically lower than that of classical scrapie or BSE, especially in relation to the expression level of the prion protein

La place du thermalisme dans les traitements de l'insuffisance veineuse chronique

BORDEAUX2-BU Santé (330632101) / SudocSudocFranceF

Identification of tissular origin of particles based on autofluorescence multispectral image analysis at the macroscopic scale

Powders produced from plant materials are heterogeneous in relation to native plant heterogeneity, and during grinding, dissociation often occurred at the tissue scale. The tissue composition of powdery samples could be modified through dry fractionation diagrams and impact their end-uses properties. If tissue identification is often made on native plant structure, this characterization is not straightforward in destructured samples such powders. Taking advantage of the autofluorescence properties of cell wall components, multispectral image acquisition is envisioned to identify the tissular origin of particles. Images were acquired on maize stem sections and ground tissues isolated from the same stem by hand dissection. The variability in fluorescence intensity profiles was analysed using principal component analysis. The correspondence between fluorescence profiles and the different tissues observed in maize sections was assessed based on histology or known compositional heterogeneity. Similar variability was encountered in fluorescence profiles extracted from powder leading to the potential ability to predict tissular origin based on this autofluorescence multispectral signal

Structural, Culinary, Nutritional and Anti-Nutritional Properties of High Protein, Gluten Free, 100% Legume Pasta.

Wheat pasta has a compact structure built by a gluten network entrapping starch granules resulting in a low glycemic index, but is nevertheless unsuitable for gluten-intolerant people. High protein gluten-free legume flours, rich in fibers, resistant starch and minerals are thus a good alternative for gluten-free pasta production. In this study, gluten-free pasta was produced exclusively from faba, lentil or black-gram flours. The relationship between their structure, their cooking and Rheological properties and their in-vitro starch digestion was analyzed and compared to cereal gluten-free commercial pasta. Trypsin inhibitory activity, phytic acid and α-galactosides were determined in flours and in cooked pasta. All legume pasta were rich in protein, resistant starch and fibers. They had a thick but weak protein network, which is built during the pasta cooking step. This particular structure altered pasta springiness and increased cooking losses. Black-gram pasta, which is especially rich in soluble fibers, differed from faba and lentil pasta, with high springiness (0.85 vs. 0.75) and less loss during cooking. In comparison to a commercial cereal gluten-free pasta, all the legume pasta lost less material during cooking but was less cohesive and springy. Interestingly, due to their particular composition and structure, lentil and faba pasta released their starch more slowly than the commercial gluten-free pasta during the in-vitro digestion process. Anti-nutritional factors in legumes, such as trypsin inhibitory activity and α-galactosides were reduced by up to 82% and 73%, respectively, by pasta processing and cooking. However, these processing steps had a minor effect on phytic acid. This study demonstrates the advantages of using legumes for the production of gluten-free pasta with a low glycemic index and high nutritional quality

Contribution of multispectral autofluorescence imaging to histochemistry in understanding sorghum internode hydrolysis pattern

International audienceSorghum is the world’s fifth largest cereal crop and exhibits high biomass yield potentials. This cereal is suitable to support the development of biomass value chains in temperate and semi-arid environments. Digestibility of plant feedstock is one of the key properties and is largely dependent on the overall lignification of the plant which is monitored at the tissue scale by the relative amounts and composition of plant organ. To obtain details on organ anatomy and spatial distribution of main components, medium-throughput histochemical methods have been developed on maize and sorghum internodes [1,2]. FASGA staining procedure is based onthe competition between 2 dyes and reveals regions with different staining colour (essentially red and blue color) which may be interpreted in terms of tissue ligninification [3]. In addition to staining procedures, the specific spectral properties of phenolic compounds could also be exploited to map their distributions using spectral imaging technics. Multispectral autofluorescence imaging was successfully applied to maize stem internode to reveal differences in cell wall phenolic compounds distribution (lignin and hydroxycinnamic acids) [4]. The objective of this work was to evaluate the relevance of multispectral autofluorescence imaging to better understand contrasted hydrolysis patterns observed inside the sorghum stem internode. Two sorghum genotypes differing in their hydrolysis yield were selected. Internodes (at the bottom of the stem) from four healthy plants harvested at the grain filling stage were characterized for histochemistry in relation to spatial-susceptibility to enzymatic hydrolysis. Cell wall digestion was realized with a combined cellulase/hemicellulase 4% mix during 72h. The hydrolyzed sections were stained with FASGA and the hydrolysis yields were estimated by comparing the area of the section before and after hydrolysis (Figure 1A,B).. Images were analyzed with the open-source ImageJ freeware4 and a dedicated script to quantify anatomical traits. Multispectral autofluorescence images (Figure 1C) were acquired using a multi-zoom macroscope AZ100M (Nikon, Japan) equipped with 4 filter blocks to acquire images under UV, blue and green excitation lights. Emission light was recovered through long pass filters and, taking advantage of the RGB channels of the color camera, each image was split in three channels and stack alltogether to obtain a 12 channels multispectral image. In such multispectral images, each pixel is characterized by an intensity profile that can be considered as a spectral signature (Figure 1D).Observed after FASGA staining, both genotypes showed typical sorghum internode organization with two main anatomical zones: (1) a mainly red-stained peripheral zone Z1 (rind), which is rich in vascular bundles and sclerenchyma cells and is surrounded by an epidermis on the most external part, and (2) an inner zone Z2 (pith), composed of vascular bundles spread into blue-stained parenchyma. As already observed, no hydrolysis of the red-stained zone (Z1) was evidenced for these two genotypes. Different hydrolysis pattern in the low-lignified zone (Z2) was revealed. One genotype showed a limited losse of material (below 10% for two plants and up to 25 % for the other two plants). For the second genotype hydrolysis yields were about 40-50%, corresponding to an almost complete degradataion of the Z2 region. For both genotypes, the hydrolysis was more pronounced in the middle of the internode cross section. Comparison of the brightfield images with the color representation of the average multispectral images shows that all the cell wall showed autofluorescence under UV or visible excitation. Differences in color in this multispectral image highlight the main tissues with highly lignified tissue appearing as pink/orange. No visual difference between parenchyma was evidenced and more precise analysis of spectral signature was carried out. Spectral signature of blue-stained parenchyma cell walls were extracted in both hydrolysed and not hydrolysed regions. Whole spectral signatures were compared through principal component analysis. Slight differences were observed, in particular under UV-excitation light and must be faced to overall spectral variability (within a cross section and between plants). The relevance of combined classical histochemical and multispectral imaging was emphasized in this study allowing to highlight the different behaviours of constratsing genotypes and different regions of the internodes