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How the diverse polysaccharides present in plant cell walls are assembled and interlinked into functional composites is not known in detail. Here, using two novel monoclonal antibodies and a carbohydrate-binding module directed against the mannan group of hemicellulose cell wall polysaccharides, we show that molecular recognition of mannan polysaccharides present in intact cell walls is severely restricted. In secondary cell walls, mannan esterification can prevent probe recognition of epitopes/ligands, and detection of mannans in primary cell walls can be effectively blocked by the presence of pectic homogalacturonan. Masking by pectic homogalacturonan is shown to be a widespread phenomenon in parenchyma systems, and masked mannan was found to be a feature of cell wall regions at pit fields. Direct fluorescence imaging using a mannan-specific carbohydrate-binding module and sequential enzyme treatments with an endo-β-mannanase confirmed the presence of cryptic epitopes and that the masking of primary cell wall mannan by pectin is a potential mechanism for controlling cell wall micro-environments.

Received: 23 May 2007 Returned for revision: 10 July 2007 Accepted: 16 July 2007 Published electronically: 19 September 2007†Background and Aims Projections of cell wall material into the intercellular spaces between parenchymatic cellshave been observed since the mid-19th century. Histochemical staining suggested that these intercellular protuber-ances are probably pectic in nature, but uncertainties about their origin, composition and biological function(s) haveremained.†Methods Using electron and light microscopy, including immunohistochemical methods, the structure and thepresence of some major cell wall macromolecules in the intercellular pectic protuberances (IPPs) of the corticalparenchyma have been studied in a specimen of the Asplenium aethiopicum complex.†Key Results IPPs contained pectic homogalacturonan, but no evidence for pectic rhamnogalacturonan-I or xylo-galacturonan epitopes was obtained. Arabinogalactan-proteins and xylan were not detected in cell walls, middlelamellae or IPPs of the cortical parenchyma, whereas xyloglucan was only found in its cell walls. Extensin(hydroxyproline-rich glycoproteins) LM1 and JIM11 and JIM20 epitopes were detected specifically in IPPs butnot in their adjacent cell walls or middle lamellae.†Conclusions It is postulated that IPPs do not originate exclusively from the middle lamellae because extensins wereonly found in IPPs and not in surrounding cell walls, intercellular space linings or middle lamellae, and because IPPsand their adjacent cell walls are discontinuous.Key words: Pteridophyta, Asplenium, immunohistochemistry, pectic polysaccharides, extensin, cell wall, fern.

Summary High-quality sections are indispensable for many scientific studies. Most published methods are often time-consuming or require special devices. We present an easy, quick and low-cost method for oriented embedding of thin structures using glycol methacrylate resin and self-constructed, reusable embedding tools made of overhead transparencies. This technique allows for more flexibility in orientation than other methods, enabling precise transverse, longitudinal and even oblique sectioning.

A list of 59 newly recorded Pteridophytes from the Bukit Baka- Bukit Raya National Park in Central Kalimantan is presented. Nine species are recorded for Indonesian Borneo (Kalimantan) for the first time: Diplazium polycarpum, Pronephrium peltatum var. persetiferum, Pteris asperula, Selliguea enervis, Sphaerostephanos latebrosus, Sphaerostephanos reconditus, Syngramma quinata, Tectaria tricuspis, and Trichomanes humile. Previously, Sphaerostephanos reconditus, and Tectaria palmata var. dimorpha were only known from their type localities.

Background While it is kno3wn that complex tissues with specialized functions emerged during land plant evolution, it is not clear how cell wall polymers and their structural variants are associated with specific tissues or cell types. Moreover, due to the economic importance of many flowering plants, ferns have been largely neglected in cell wall comparative studies. Results To explore fern cell wall diversity sets of monoclonal antibodies directed to matrix glycans of angiosperm cell walls have been used in glycan microarray and in situ analyses with 76 fern species and four species of lycophytes. All major matrix glycans were present as indicated by epitope detection with some variations in abundance. Pectic HG epitopes were of low abundance in lycophytes and the CCRC-M1 fucosylated xyloglucan epitope was largely absent from the Aspleniaceae. The LM15 XXXG epitope was detected widely across the ferns and specifically associated with phloem cell walls and similarly the LM11 xylan epitope was associated with xylem cell walls. The LM5 galactan and LM6 arabinan epitopes, linked to pectic supramolecules in angiosperms, were associated with vascular structures with only limited detection in ground tissues. Mannan epitopes were found to be associated with the development of mechanical tissues. We provided the first evidence for the presence of MLG in leptosporangiate ferns. Conclusions The data sets indicate that cell wall diversity in land plants is multifaceted and that matrix glycan epitopes display complex spatio-temporal and phylogenetic distribution patterns that are likely to relate to the evolution of land plant body plans. Electronic supplementary material The online version of this article (doi:10.1186/s12870-014-0362-8) contains supplementary material, which is available to authorized users.

Nanomaterials are more and more used in various situations, such as catalysis,color, optics, etc. To optimize their use, it is necessary to better understand reactions andinteractions taking place at these scales. This PhD thesis aims at exploring the links betweensynthesis conditions, particle morphology and their properties. In particular, we chose a tostudy a model-material: cerium (IV) oxide. CeO2 nanoparticles have been obtained bymicrowave-heating assisted solvothermal synthesis. Morphologies obtained and studied havebeen: cubes, octahedrons and rods. We tried to to give an explanation on how these synthesesallowed the formation of such morphologies. Gold has then be deposed on the surface of theseCeO2 nanoparticles, and studied by a combination of Transmission Electron Microscopystudies, and computer modelizations., Les nanomatériaux sont de plus en plus utilisés dans de nombreusesapplications, que cela soit pour la catalyse, la coloration, l’optique, etc. Pour optimiser leurutilisation, il est nécessaire de mieux comprendre les réactions et interactions ayant lieu à ceséchelles. Cette thèse se propose d’essayer d’explorer les liens entre conditions de synthèse,morphologie de particules, et propriétés de celles-ci. En particulier, nous avons opté pourl’étude d’un matériau modèle : l’oxyde de cérium (IV). Les nanoparticules de CeO2 ont étéobtenues par voie de synthèse solvothermale assistée par chauffage micro-ondes. Lesmorphologies des nanoparticules de CeO2 étudiées ont été : les cubes, les octaèdres et lesbâtonnets, et nous avons essayé de fournir une explication à leur obtention par la voie desynthèse utilisée. De l’or a ensuite été déposé en surface des ces nanoparticules de CeO2 etétudié par une combinaison d’études par Microscopie Électronique en Transmission et demodélisations numériques.