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1
Kirby, James. "Multiplicity and organisation of plant cell wall degrading enzymes in Ruminococcus flavefaciens 17." Thesis, University of Aberdeen, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362230.
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The Gram-positive, strictly anaerobic bacterium, R. flavefaciens, plays an important role in the degradation of plant cell wall polysaccharides in the rumen. There is a paucity of information available, however, regarding the multiplicity and organisation of R. flavefaciens cellulolytic and xylanolytic enzyme systems. A technique involving PCR amplification of DNA with primers designed from conserved sequences, followed by hybridisation of the PCR products to chromosomal DNA, has led to an estimate of xylanase gene multiplicity in R. flavefaciens. The xylanase-specific primers were also useful in the isolation and sequencing of a partial xylanase gene, xynC. Although R. flavefaciens 17 appears to produce a cellulose-binding enzyme-complex, none of the individual enzymes examined was found to bind cellulose in isolation. However, a 210 kDa protein which is present in the complex was shown to bind cellulose after isolation from a renatured SDS-gel. In order to look for genetic evidence for a cellulose-binding mechanism, sequencing of the R. flavefaciens 17 endoglucanase gene, endA, was completed from PCR products. The carboxy-terminus of the predicted endA product consists of a domain which is similar to dockerins found in Clostridium thermocellum polysaccharidases. Homologous domains are also found in the R. flavefaciens xylanases, XynB and XynD. As the C. thermocellum dockerin domains mediate binding to the 210 kDa scaffolding protein in the cellulosome complex, it is likely that the R. flavefaciens domains play a similar role in assembly of a cellulosome-like complex (Lamed and Bayer, 1994). A gene which maps approximately 1.5 kb downstream from endA on the R. flavefaciens 17 chromosome was sequenced and found to be homologous to nifS genes from nitrogen-fixing bacteria (Zheng et al, 1993). The R. flavefaciens NifS product catalyses the production of sulphur from cysteine, and is suspected to partake in the assembly of iron-sulphur clusters. The precise role of NifS is not yet known, but may be related to the degradation of crystalline cellulose.
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Bonham, Victoria Anne. "Secondary cell wall specific proteins in plants." Thesis, Royal Holloway, University of London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312839.
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Good, J. C. "The study of enzymes and primers involved in the initiation of chains of glucans." Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375257.
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Ries, Laure Nicolas Annick. "Regulation of genes encoding enzymes involved in plant cell wall deconstruction in Trichoderma reesei." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13045/.
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This study describes the regulation of genes encoding plant cell wall-degrading enzymes in the presence of different carbon sources from the biotechnologically important fungus Trichoderma reesei. It was shown that different carbon sources influence fungal growth rate, biomass production and subsequent enzyme secretion. Several genes were identified and suggested to play a role in the development of conidia and in maintaining polarised growth. RNA-sequencing studies showed an increase in transcript levels of genes encoding enzymes involved in plant cell wall degradation (CAZy) as well as of genes encoding lipases, expansins, hydrophobins, G-protein coupled receptors and transporters when mycelia were cultivated in the presence of a lignocellulosic substrate (wheat straw). The encoded non-CAZy proteins were proposed to have accessory roles in carbohydrate deconstruction. A model for solid substrate recognition in T. reesei was described, based on the comparison with the one proposed for Aspergillus niger. Post-transcriptional regulation mediated by regulatory RNAs was identified for nearly 2% of all T. reesei genes, including genes encoding cell wall-degrading enzymes. Transcriptional regulation studies confirmed that transcription patterns of genes encoding enzymes involved in polysaccharide degradation differed between different carbon sources and that they are fine-tuned and dependent on factors such as culture conditions, consumption rate, assimilation of glucose and the presence of several transcription factors. The analysis of the structure of chromatin in the promoter and coding regions of one of these genes, cbh1, revealed different nucleosome positioning patterns under repressing (glucose) and inducing (sophorose, cellulose) conditions. CRE1, the carbon catabolite repressor in T. reesei was shown to be involved in the repression of many CAZy and non-CAZy encoding genes. Furthermore, CRE1 was also shown to be important for nucleosome positioning within the cbh1 coding region under repressing conditions and proposed to do so by interaction with (a) yet unidentified protein(s).
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Tao, Titus. "Functional characterization of ZmGRP5, a glycine-rich protein specifically expressed in the cell wall of maize silk tissue." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26780.
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Silk tissue is a specialized reproductive tissue of the maize plant, equivalent to the stigma and style portion of the female inflorescence. The moist and nutrient rich properties of maize silk tissue that facilitate pollen reception and the support of pollen tube growth also make maize silk a preferred site of infection by fungal pathogens such as Fusarium graminearum. The cDNA clone zmgrp5 was isolated in a previous study to identify silk tissue-specific genes. ZmGRP5, the encoded protein, was predicted to be a cell wall glycine-rich protein (GRP) and was experimentally characterized in this study. Using polyclonal antiserum, immunoblot analysis confirmed the silk tissue specificity of the protein. Additionally, subcellular fractionation studies confirmed ZmGRP5 localization in the cell wall fraction, and not in any other subcellular fractions. Interaction of ZmGRP5 with the cell wall matrix was observed to be disrupted by the addition of the reducing agent beta-ME. The reversible nature of disulfide bond formation and disruption under different redox conditions suggest that ZmGRP5 could potentially be important in the regulation of cell wall structural properties such as elasticity and rigidity in accordance with environmental and developmental changes. The variable immobilization of ZmGRP5 to the cell wall matrix could also serve as a potential mechanism of activation or inactivation of any non-structural functions. The identification of potential post-translational modifications such as phosphorylation and glycosylation, which are rarely observed in other cell wall GRPs, suggest that the functional significance of these modifications in ZmGRP5 is worthy of further study.
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Messenger, David James. "Impact of UV light on the plant cell wall, methane emissions and ROS production." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4347.
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This study presents the first attempt to combine the fields of ultraviolet (UV) photobiology, plant cell wall biochemistry, aerobic methane production and reactive oxygen species (ROS) mechanisms to investigate the effect of UV radiation on vegetation foliage. Following reports of a 17% increase in decomposition rates in oak (Quercus robur) due to increased UV, which were later ascribed to changes in cell wall carbohydrate extractability, this study investigated the effects of decreased UV levels on ash (Fraxinus excelsior), a fast-growing deciduous tree species. A field experiment was set up in Surrey, UK, with ash seedlings growing under polytunnels made of plastics chosen for the selective transmission of either all UV wavelengths, UV-A only, or no UV. In a subsequent field decomposition experiment on end-of-season leaves, a significant increase of 10% in decomposition rate was found after one year due to removal of UV-B. However, no significant changes in cell wall composition were found, and a sequential extraction of carbohydrate with different extractants suggested no effects of the UV treatments on cell wall structure. Meanwhile, the first observations of aerobic production of methane from vegetation were reported. Pectin, a key cell wall polysaccharide, was identified as a putative source of methane, but no mechanism was suggested for this production. This study therefore tested the effect of UV irradiation on methane emissions from pectin. A linear response of methane emissions against UV irradiation was found. UV-irradiation of de-esterified pectin produced no methane, demonstrating esters (probably methyl esters) to be the source of the observed methane. Addition of ROS-scavengers significantly decreased emissions from pectin, while addition of ROS without UV produced large quantities of methane. Therefore, this study proposes that UV light is generating ROS which are then attacking methyl esters to create methane. The study also demonstrates that this mechanism has the potential to generate several types of methyl halides. These findings may have implications for the global methane budget. In an attempt to demonstrate ROS generation in vivo by UV irradiation, radio-labelling techniques were developed to detect the presence of oxo groups, a product of carbohydrate attack by ROS. Using NaB3H4, the polysaccharides of ash leaflets from the field experiment were radio-labelled, but did not show any significant decrease in oxo groups due to UV treatments. However, UV-irradiation of lettuce leaves showed a significant increase in radio-labelling, suggesting increased UV irradiation caused an increase in the production of ROS. The study shows that the use of this radio-labelling technique has the potential to detect changes in ROS production due to changes in UV levels and could be used to demonstrate a link between ROS levels and methane emissions.
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Dong, Wen. "Extensin Peroxidase Identification and Characterization in Solanum lycopersicum." Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1425894387.
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Pegg, Timothy Joseph. "Cell Wall Carbohydrate Modifications during Flooding-Induced Aerenchyma Formation in Fabaceae Roots." Miami University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1626443795433208.
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Wiemels, Richard E. "Cloning, Expression, and Biochemical Assay of Putative Xyloglucan-specific Fucosyltransferases from Wheat and Brachypodium." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1368012677.
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Jiang, Nan. "Characterization of TaXPol-1, a Xylan Synthase Complex from Wheat." Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1437153132.
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Nething, Daniel B. "Detection of Cellulose Synthase Antisense Transcripts Involved in Regulating Cell Wall Biosynthesis in Barley, Brachypodium and Arabidopsis." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1500996680467756.
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Mishler-Elmore, John William. "Expression Profiling and Recombinant Production of TomEP, a Tomato Extensin Peroxidase." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1585732848912595.
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Liang, Yan. "Identification and Characterization of Galactosyltransferases and Fucosyltransferases Involved in Arabinogalactan-Protein Glycosylation." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1343410954.
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López, Hernández Federico. "Identification of the role of [methyl]glucuronic acid on arabinogalactan polysaccharides in Arabidopsis thaliana." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/276328.
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Arabinogalactan proteins (AGPs) are proteoglycans heavily substituted by arabinogalactan polysaccharides. These are composed of arabinose and galactose, and minor sugars such as glucuronic acid (GlcA), fucose and xylose. The arabinogalactan polysaccharides do not decorate classical AGPs exclusively, but they can also be found decorating a wide range of proteins. Arabinogalactan proteins have been implicated in many processes of plant development. Recently, AGPs were proposed to bind and store calcium at the plasma membrane. They are extracellular, and are localised mainly at the plasma membrane via a GPI-anchor. They can also be soluble in the apoplast. Their low abundance, chemical similarity and high functional redundancy have hindered their study. My strategy to overcome these difficulties was to study knock-out Arabidopsis thaliana plants of glycosyltransferases that transfer sugars specifically onto AG-polysaccharides. Glucuronic acid makes up about 10% of the arabinogalactan polysaccharide structure in Arabidopsis thaliana cell culture AGPs. Previously, the glucuronic acid transferase A TGLCA T14A, a member of the CAZy Glycosyl Transferase 14 family, was shown to transfer GlcA specifically onto AGPs, and knock-out Arabidopsis plants showed a 30% reduction in [Me]GlcA substitution in AGP-enriched preparations. However, no clear growth phenotype was observed. The characterisation of knock-out plants of other GT14 family members and combinations thereof is described here. Based on previous studies (Lamport and Várnai, 2013), I assayed in vitro the calcium binding capacity of AGP extracts from WT and knock-out plants. The results showed that AGP extracts from knock-out plants can hold less calcium than WT plants in vitro. A wide range of plant growth phenotypes were identified. Growth phenotypes can be explained by changes in the cytoskeleton and deficiencies in calcium signaling. Our evidence suggests links between structural deficiencies of extracellular proteoglycans to extracellular calcium and cytoskeleton. This research has the potential to create a new model system for the study of molecular mechanisms dependent on calcium that drive cell expansion, division and differentiation in plants.
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Kjaer, Lars. "Characterization of the plant cell wall response to isoxaben induced cell wall damage." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/9630.
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Cell wall damage (CWD) causes extensive changes in cell wall composition and structure, which seem to be mediated by a cell wall integrity signalling mechanism. Though parallels have been found to the cell wall integrity signalling pathway in yeast, it is clear that a more detailed study in plants is necessary to understand the process in detail. Classical induction of CWD (pathogens, stress, foraging animals) is often local, or overlaps with other response systems and has rarely been studied specifically. Treating Arabidopsis thaliana seedlings with isoxaben (a specific CESA3 and 6 inhibitor) allows the induction of highly specific CWD in growing tissues. Cross-referencing the genes which respond to isoxaben induced CWD with publically available tissue expression data allow identification of genes of interest. Based on this analysis, 108 genes were identified, and KO insertion lines isolated to assign a biological function to the individual candidate gene. 24 of these genes have been characterised both with and without CWD induction in this PhD. Genes of particular interest were picked using a FTIR clustering method. This method identified genes for which the insertions changed the response to isoxaben and genes which have a different cell wall composition from the outset. Modified cell wall composition of mutants was confirmed using chemical assays and lignin staining for the 10 selected genes. Of these, 6 genes had substantial mutant phenotypes. Saccharification assay showed high sugar yields for more than 50% of the candidates, in seedlings and stems. The specific cell wall features which lead to this improvement in saccharification have yet to be established.
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Tsang, Dat. "The plant cell wall integrity sensing mechanism." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/the-plant-cell-wall-integrity-sensing-mechanism(390d2fb7-7a4c-48ce-b0a3-caca46c3e41b).html.
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Plant cell walls are dynamic and responsive structures rather than rigid cages. Disruption of cell wall integrity prevents cell expansion: for example, inhibition of cellulose biosynthesis with isoxaben rapidly reduces root elongation. This is not a passive consequence of mechanical failure but an active response regulated by cell wall integrity (CWI) sensing pathway. Interestingly, the plant response to pathogen-associated molecular patterns (PAMPs) like flagellin shares many similarities with the CWI pathway response; such as the production of reactive oxygen species (ROS) and lignin. While root elongation is also reduced by flagellin, microarrays show that the two treatments lead to a very different expression profile. Little is known about the mechanisms and components of the CWI pathway. Here we show that inhibiting the biosynthesis of 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of the plant hormones ethylene, restores elongation in roots treated with isoxaben but exacerbates the extent of the cell wall damage. Unexpectedly, ethylene itself is not required for the process. Further experiments show that the response to flg22 in roots also requires this putative signalling pathway. Auxin appears to work downstream of ACC since inhibiting auxin activity prevents growth reduction in roots treated with ACC, isoxaben or flg22We have also identified a receptor-like kinase (SRK) which is required for growth repression in root cells that are experiencing cell wall damage. Expression of this gene is rapidly and transiently induced by isoxaben. SRK (S-locus RLK) is part of a highly expanded locus of RLKs related to self-incompatibility proteins in Brassica. However, while other genes of this family are induced by cell wall stress, only SRK mutants are insensitive to acute cell wall damage. Further characterisation of the SRK is under way to confirm its role in the CWI pathway.
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Somner, Elizabeth Ann. "Antibiotic inhibitors of bacterial cell wall synthesis." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359831.
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Biggs, Karen. "Tyrosine cross-links in plant cell wall glycoprotein." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/10809.
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Round, Andrew Neal. "Atomic force microscopy of plant cell wall polysaccharides." Thesis, University of East Anglia, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297475.
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Nunan, Kylie. "Cell wall metabolism in developing grape berries /." Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09APSP/09pspn972.pdf.
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Bekker, Jan P. I. "Genetic manipulation of the cell wall composition of sugarcane." Thesis, Link to online version, 2007. http://hdl.handle.net/10019/336.
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Kaewthai, Nomchit. "In vitro and in vivo approaches in the characterization of XTH gene products." Doctoral thesis, KTH, Glykovetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-28222.
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ABSTRACT The xyloglucan endo-transglycosylase/hydrolase (XTH) genes are found in all vascular and some nonvascular plants. The XTH genes encode proteins which comprise a subfamily of glycoside hydrolase (GH) family 16 in the Carbohydrate-Active enZYmes (CAZY) classification. The XTH gene products are believed to play intrinsic role in cell wall modification during growth and development throughout the lifetime of the plant. In the present investigation, biochemical and reverse genetic approaches were used to better understand the functions of individual members of the XTH gene family of two important plants: the model organism Arabidopsis thaliana and the grain crop barley (Hordeum vulgare). A phylogenetic tree of the xyloglucan-active enzymes of GH16 has previously been constructed, where enzymes with similar activities have been shown to cluster together. Several members of phylogenetic Group I/II and III-B, predicted to exhibit xyloglucan endo-transglycosylase activity (EC 2.4.1.207) and members of Group III-A, predicted to exhibit xyloglucan endo-hydrolase activity (EC 3.2.1.151), were included to analyze the functional diversity of XTH gene products. A heterologous expression system using the yeast Pichia pastoris was found to be effective for recombinant protein production with a success rate of ca. 50%. XTH gene products were obtained in soluble and active forms for subsequent biochemical characterization. In order to be able to screen larger numbers of protein producing clones, a fast and easy method is required to identify clones expressing active protein in high enough amounts. Thus, a miniaturized XET/XEH assay for high-throughput analysis was developed, which was able to identify activities with good precision and with a reduced time and materials consumption and a reduced work load. Enzyme kinetic analysis indicated that the XET or XEH activity of all XTH gene products characterized in the present study corresponded to predictions based on the previously revised phylogenetic clustering. To gain insight into the biological function of the predominant XEHs AtXTH31 and AtXTH32, which are highly expressed in rapidly developing tissues, a reverse genetic approach was employed using T-DNA insertion lines of the A. thaliana Columbia ecotype. Genotypic and phenotypic characterization, together with in situ assays of XET and XEH activities, in single- and double-knock-out mutants indicated that these Group III-A enzymes are active in expanding tissues of the A. thaliana roots and hypocotyl. Although suppression of in muro XEH activity was clearly observed in the double-knock-out, no significant growth phenotype was observed, with the exception that radicle emergence appeared to be faster than in the wild type plants. Keywords: Arabidopis thaliana, Hordeum vulgare, plant cell wall, xyloglucan, glycoside hydrolase family 16, xyloglucan endo-transglycosylase/hydrolase gene family, xyloglucan endo-transglycosylase, xyloglucan endo-hydrolase, heterologous protein expression, Pichia pastoris, T-DNA insertion, in situ XET/XEH assay, high-throughput screeningQC 20110114
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Motshwene, Precious Gugulethu. "Yeast cell wall proteomics: a tale of two proteins." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/4300.
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Bibliography: leaves 53-57.This thesis investigates cell wall proteins, the presence of which increased in concentration as a result of stress. Two such proteins were found, phosphoglycerate mutase and Hsp 12. Studies on these proteins are reported in chapters 2 (phosphoglycerate mutase) and chapter 3 (Hsp 12).
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Taylor, Larry Edmund II. "Degradation of plant cell wall polysaccharides by saccharophagus degradans." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3242.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Marine-Estuarine-Environmental Sciences. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Götz, Stephan. "The molecular basis of plant cell wall oligosaccharide formation." Thesis, University of East Anglia, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.580570.
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The characterisation and identification of glycosyltransferases (GTs) involved in matrix polysaccharide biosynthesis has gained increasing interest as they affect our ability to influence, engineer and manipulate plant cell wall biosynthesis. To date, only a small number of genes coding for matrix polysaccharide biosynthesis-related glycosyltransferases have been identified. Mostly, biochemical proof of activity is still needed for final confirmation of function. To address such problems, this study established an initial biochemical activity testing methodology combined with final gene identification in one approach. A substrate library was established with different sugar nucleotide donor and oligosaccharide acceptor combinations to address a comprehensive range of glycosyltransferase activities. To overcome well-known problems with radioactive assay formats, an APTS (8-Amino- 1,3,6,PyreneTriSulfonic acid) based detection methodology was introduced, which allowed sensitive and flexible analysis of the glycosyltransferases.
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Gucciardo, SeÌbastien. "Plant cell wall glycoproteins involved in legume nodule development." Thesis, University of East Anglia, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405724.
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Vaughan, David. "Characterisation of the plant cell wall under cold stress." Thesis, University of York, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251815.
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Morris, Sheila. "Atomic force microscopy studies of plant cell wall components." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420915.
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Li, Zhuo. "Bio-based composites that mimic the plant cell wall." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/32088.
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Nature creates high performance materials under modest conditions, i.e., neutral pH and ambient temperature and pressure. One of the most significant materials is the plant cell wall. The plant cell wall is a composite of oriented cellulose microfibrils reinforcing a lignin/hemicellulose matrix. In principle, the plant cell wall composite is designed much like a synthetic fiber-reinforced polymer composite. Unlike synthetic composites, the plant cell wall has an excellent combination of high modulus, strength, toughness and low density that originates in the optimal interactions between the biopolymers. Therefore, to produce high performance composites, a unique route may be to mimic a biological system like the plant cell wall. The present work focuses on understanding the thermodynamics of biopolymer assembly to exploit the process in vitro.
In our system, we use an already polymerized nanocellulose template and polymerize phenolic monomers on the template using a peroxidase enzyme. In the first part, we have polymerized phenol using horseradish peroxidase (HRP) in the presence of TEMPO-oxidized nanocellulose. Similar to native plant cell wall structures, the polyphenol-nanocellulose composite had intimate mixing of polyphenol and cellulose at the nanoscale with the presence of cellulose promoting a uniquely organized structure. The obtained composite material showed synergy that enhanced the thermal stability, hydrophobicity, and possibly mechanical properties.
In the second part, monolignol coniferyl alcohol was polymerized in the presence of nanocellulose by the same procedure. A comparison between the polyphenol composite and poly(coniferyl alcohol) (PCA) composite revealed that the propanyl substitution imparted flexibility to the PCA molecules so that they could bend and form a hollow globule structure to envelope nanocellulose inside. Polyphenol could not do this because of its rigidity.Master of Science
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Brinson, Kenneth. "Changes in cell wall of mango fruit during ripening." Thesis, Royal Holloway, University of London, 1985. http://repository.royalholloway.ac.uk/items/9ed78b9d-10cc-43c4-8ffa-eb6c36f34534/1/.
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Changes in cell walls and in the levels of polysaccharide-degrading enzymes, in mesocarp of mango fruit during ripening were investigated. Total, insoluble cell wall content declined with ripening. Galactose, arabinose, xylose and mannose were lost from the wall during ripening and autolysis of ripe mango mesocarp released arabinose and xylose into the soluble fraction. Galacturonic acid was also removed from the wall but polygalacturonase (which degrades pectic galacturonan in fruits of many other species) could not be detected. Several glycosidase activities were present in the mesocarp and, of these, a-d-galactosidase and mannosidase increased markedly during ripening. The increase in the former may be significant in the removal of wall-bound galactose accompanying ripening. Enzyme extracts prepared from ripe mangoes released galactose from cell walls isolated from unripe fruits but soluble polysaccharides released from the wall by enzyme action In vitro could not be detected by electrophoresis. Polysaccharides, composed mainly of xylose and glucose, were co-extracted with enzymic protein from mango mesocarp and there was evidence that these polymers underwent degradation during ripening. They may be derived, partly at least, from wall hemi-celluloses. It is proposed that one process contributing to cell wall breakdown and resultant tissue softening in the mango may be the enzymic hydrolysis of polysaccharides containing arabinose and galactose (possibly neutral pectic polymers) and that polygalacturonase activity probably does not contribute significantly to tissue softening The mechanism for removal of galacturonan from the wall was not established but this may result from prior removal of polysaccharides containing arabinose and galactose. Data obtained also suggest that hemi-celluloses in the wall may be degraded during ripening, Critical appraisal was made of the limitations of both preparatory and analytical methods employed and proposals made for employing better methods in further work.
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McLaughlin, Linda Frances. "Glycoproteins of the cell wall of Chlamydomonas reinhardtii." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329282.
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Cox, Andrew David. "Pseudomonas cepacia : lipopolysaccharides and polar lipids of the cell wall." Thesis, University of Hull, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306158.
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Poole, Deborah Marie. "Molecular analysis of plant cell wall hydrolases of bacterial origin." Thesis, University of Newcastle Upon Tyne, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238939.
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Braithwaite, Kerynne Lindsay. "Novel plant cell wall hydrolases from Pseudomonas fluorescens subspecies cellulosa." Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294928.
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Henshaw, Joanna Louise. "Analysis of protein-carbohydrate recognition in plant cell wall degradation." Thesis, University of Newcastle Upon Tyne, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427298.
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Cornuault, Valérie Renée. "Molecular and biochemical tools for plant cell wall glycan analysis." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/8598/.
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Plant cell walls are complex structures composed of diverse polymers: polysaccharides, proteins and sometimes phenolic compounds, varying in nature, structure and length. A study of the structure and occurrence of cell wall polysaccharides is required to be able to understand their mechanical and biological functions as well as to understand the overall architecture of cell walls. Studying cell wall polysaccharides is challenging mostly because of the limited methods and tools available for their characterisation. Chromatography systems are often used to separate and purify cell wall polysaccharides. In parallel, monoclonal antibodies (mAbs) have been largely used to study cell wall polysaccharide localisation, compositional variation and their potential mechanical properties and biological functions. However, the number of epitopes currently targeted by mAbs is limited and some polysaccharide features cannot be studied using mAbs. The project reported here was focused on the development of new methods, namely Epitope Detection Chromatography and glycan sandwich-ELISA, as well as the raising and characterisation of several new monoclonal antibodies PDT2, PDT5, PDT8, PDT10, PDT13 and PDT17. These new probes recognise various RG-I (PDT10, PDT13), AGP (PDT8, PDT17) and heteroxylan (PDT2, PDT5) specific epitopes. The Epitope Detection Chromatography can perform high resolution glycan analysis by combining the separation of polysaccharides by chromatography and their detection by specific molecular probes such as monoclonal antibodies and carbohydrate-binding modules. Contrary to numerous available polysaccharide analysis techniques EDC analysis can be performed directly on complex mixtures such as cell wall extracts and target one precise defined oligosaccharide or epitope. The development of sandwich-ELISA allows the study of multi-component complexes and inter-linked polysaccharides. The two methods can be combined to study subsets of polysaccharides. Here, the two techniques have been used together with the new set of PDT monoclonal antibodies to study cell wall polysaccharide composition and multi-polysaccharide complexes in a range of biological systems: tobacco seed endosperm, grape fruit and Arabidopsis thaliana. These studies have led to the identification of RG-I sub-families in tobacco seed and A. thaliana, as well as potential xylan-pectin linkages found in A. thaliana stem cell walls.
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O'Rourke, Christina Margaret. "Cell wall polysaccharides in charophytic algae." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/17868.
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Plants colonised land 460 million years ago and charophytes represent the closest living relatives of land plants. The ability to live on land may depend on the presence of certain cell wall polysaccharides such as xyloglucan, a hemicellulose exclusively found in land plants (Popper and Fry, 2003). The cell walls of charophytes are poorly characterised. The aim of this project was to use biochemical techniques to characterise the cell wall polysaccharides of charophytic algae in relation to early land plant phylogeny. Hydrolysis of Coleochaete scutata and Chara vulgaris cell walls in 2 M trifluoroacetic acid yielded predominantly GalA, Gal, Glc and Man residues and also some Ara, Xyl and traces of Fuc and Rha. In addition, hydrolysis of Chara pectin revealed an abundance of an unusual monosaccharide, 3-O-methyl-D-galactose, which was structurally identified by a series of 1-D and 2D NMR spectroscopy by COSY, TOCSY, NOESY and HSQC. 3-O-Methyl-D-galactose is more commonly found in lycophyte cell walls where its presence has been suggested to be related to lycophytes’ evolutionarily isolated position (Popper et al., 2001). The newly discovered presence of 3-O-methyl-D-galactose in charophyte pectin suggests that this polymer may be more complex than previously thought. Coleochaete and Chara hemicellulose extracts were fractionated by anion-exchange chromatography into five classes. A strongly anionic fraction from Chara hemicellulose was found to be rich in Glc, Xyl, Gal and Fuc suggestive of a xyloglucan-like polysaccharide. However, XEG was unable to produce diagnostic xyloglucan oligosaccharides in either Coleochaete or Chara hemicelluloses. Xylanase and mannanase digestion of Coleochaete and Chara hemicelluloses gave xylan- and mannan-oligosaccharides. Furthermore, lichenase digestion of Coleochaete hemicellulose yielded an unusual octasaccharide composed of approximately equimolar xylose and glucose. My work has shown that charophyte cell walls are a source of undiscovered monosaccharides and potentially novel pectic and hemicellulosic domains which may have important functions in enabling the successful colonisation of land by plants.
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Rastall, Robert A. "The cell surface biochemistry of Erwinia amylovora." Thesis, University of Greenwich, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258366.
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Mozolowski, Guy. "Investigating the plant cell wall degrading enzyme systems of Humicola insolens." Thesis, University of Nottingham, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.594827.
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The thermophilic filamentous fungus H. insolens has been widely recognised for its ability to degrade plant cell wall matter. Hydrolytic preparations derived from H. insolens have existing applications in industry, primarily concerning reduction in viscosity ofagro-industrial effluents. In recent years the rea li sation that effluents containing high levels of flow value plant cell wall polysaccharide could represent a significant source of fermentable sugars for a rapidly emerging bic-fuel industry has lead to the investigation of catabolic enzyme systems of a number of saprophytic organisms. This thesis presents a study of the H insolens derived hydrolytic preparation DEPOL 740L. DEPOL 740L has been shown to contain plant cell wall polysaccharide degrading enzymes which exhibit a high degree of efficacy against a variety of substrates. This study provides insight into the hydrolytic properties of DE POL 740L and the reasons for its efficacy. Evidence is presented which suggest that organisation of the individual catalytic components of the system into complex, multi-subunit structures may be partially responsible for the observed hydrolytic efficiency. In addition two novel enzymes were purified from the preparation and subsequently characterised . A type 8 feruloyl esterase was shown to have physico-chemical properties typical of this group of fungal enzymes. It was also shown to exhibit unusual properties at extremes of pH, these observations were interpreted as a mechanism designed to protect the enzyme from hydrolysis under extreme conditions. Furthermore, a novel 8-1 ,4-xylosidase enzyme was shown to exhibit remarkable physico-chemical properties, displaying an affinity for extremely high tem peratures and kinetic properties which suggest that it is among the most active and catalytically efficient enzymes of this type isolated thus far.
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Chen, Limei. "Investigation of changes in plant cell wall structure by vibrational spectroscopy." Thesis, University of East Anglia, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389264.
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Carlile, Amanda Jane. "Cell wall degrading enzymes of the plant pathogenic fungus Stagonospora nodorum." Thesis, University of Bath, 1999. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299845.
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Fujino, Takeshi. "Visualization of Molecular Architecture of the Cell Wall during Plant Growth." Kyoto University, 2000. http://hdl.handle.net/2433/181052.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第8423号
農博第1107号
新制||農||799(附属図書館)
学位論文||H12||N3380(農学部図書室)
UT51-2000-F327
京都大学大学院農学研究科林産工学専攻
(主査)教授 伊東 隆夫, 教授 藤田 稔, 教授 東 順一
学位規則第4条第1項該当
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Lancaster, M. J. "Studies on the export of extracellular proteins through the bacterial cell wall." Thesis, University of Bristol, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356221.
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Mohler, Kyle Edward. "Transglucosylation of cell wall polysaccharides in equisetum fluviatile." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/9505.
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Plant cell walls determine cellular shape and provide structural support for the entire plant. Polysaccharides, comprising the major components of the wall, are actively remodelled throughout development. Xyloglucan endotransglucosylase (XET)/hydrolase (XTH, EC 2.4.1.207) cleaves xyloglucan (XyG), the donor substrate, and attaches a portion to another XyG chain, the acceptor substrate. Recently, a novel transglucosylase called mixed-linkage β-glucan (MLG) : XyG endotransglucosylase (MXE) was discovered in horsetails (Equisetum spp.) that could attach a portion of MLG to XyG, resulting in a hetero-polymer product. My aims were to further investigate the nature of this activity, biochemically characterize the enzyme, and explore its physiological role. MXE activity was attributable to an enzyme unlike Equisetum XTHs. MXE had a p1 of 4.1 (XTHs were 6.6-9), a pH optimum of 6.3 (XTHs preferred 5.5), and had higher activity using smaller oligosaccharide acceptor substrates like XXXGol (XTHs were more active using XLLGol). Importantly, the MXE protein was shown to utilize both MLG and XyG as donor substrates, and therefore have both MXE and XET activity. Also, the enzyme was capable of using various glucan oligosaccharides (O) as substrates, including MLGO, XyGO, and cello-O, but not laminari-O. By using a novel ex vivo approach, the proportion of extractable MXE product to XET product was found to increase in older tissues. Transglucosylase products were localized in sclerenchyma and structural parenchyma by in situ assays, implying a strenghening function for MXE. Surprisingly, another novel activity was discovered that could covalently attach cellulose to XyG, and termed cellulose : xyloglucan endotransglucosylase (CXE). This activity was attributed to the MXE enzyme, implying that the protein is a promiscuous endotransglucosylase. The presence of CXE in other plants has not yet been tested. Besides being a novel discovery in plant cell biology, the modification of cellulose has applications in a number of industries.
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Rodrigues, Maria Juliana Calderan. "Proteome characterization of sugarcane primary cell wall." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/11/11137/tde-20122012-160756/.
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This study provides information to support the use of plant cell wall, from sugarcane bagasse, to produce cellulosic ethanol. Therewith, cell wall proteins from sugarcane cells cultures, leaves and culms were identified. To do so, different protocols were used. Using two-month-old leaves and culms, the extractions were performed using a destructive method, based on griding the tissues, submitting them to a growing gradient of succrose and centrifugation, being the cell wall extract later isolated by washing on a nylon net. After that, the cell wall proteins were extracted using two salts, 0,2 M CaCl2 and 2 M LiCl. Using cultured cells, a similar protocol was used, but it had a previous step of separation of the cell wall through grinding and precipitation in glycerol 15%. Using culms of the same age, a nondestructive protocol was tested based on vacuum infiltration of the tissues in the same salts already described, 0,2 M CaCl2 and 2 M LiCl, and posterior centrifugation. Two replicates were used from two-month-old plants and three in the case of suspension cells. The complex samples were digested, fractionated and sequenced through mass spectrometry, using SYNAPT G2HDMS coupled to nanoACQUITY, both from Waters. Peptides were processed using ProteinLynx 2.5 Global Server against sugarcane translated-EST database. Using bioinformatic programs, such as Blast2GO, it was possible to find the annotation and classification of similar proteins. Only proteins equally found in all repetitions were considered in the main analysis. SignalP, WolfPSORT, TargetP, TMHMM and Predotar were used to predict the subcellular location, both from ESTs and blasted proteins, and only the proteins predicted to be secreted in two or more programs were considered as cell wall proteins. Altogether, 157 different SAS related to sugarcane cell wall were found. Among these, 101 different cell wall proteins were characterized from eight functional classes. The method based on vacuum infiltration seems to be the most efficient one, since it had almost half, 48,84% of the proteins predicted to be secreted, which is a good percentage when comparing to other studies. From secreted proteins most of them were related to lipid metabolism, as lipid-transfer proteins, oxido-reductases, such as peroxidases, cell wall modifying enzymes, like glycoside-hydrolases, proteases, proteins with interacting domains, signaling proteins and several others. Results are in agreement with the expected role of the extracellular matrix in polysaccharide metabolism and signaling phenomena. Therefore, this work provided valuable information about sugarcane cell wall that can lead to future studies to enhance cellulosic ethanol production.Este estudo fornece informação para auxiliar o uso da parede celular vegetal, a partir do bagaço de cana, para a produção de etanol celulósico. Com isso, as proteínas da parede celular de folhas, colmos e células em suspensão foram identificadas. Para isso, foram utilizados diferentes protocolos. Utilizando folhas e colmos de cana-de-açúcar de dois meses de idade, as extracções foram realizadas por meio de método destrutivo, com base na trituração dos tecidos, submetendo-os a gradiente crescente de sacarose e centrifugação, sendo a parede da célula extraída e depois isolada por lavagem sobre uma rede de nylon. Depois disso, as proteínas de parede celular foram extraídas utilizando dois sais, 0,2 M de CaCl2 e 2 M de LiCl. Para células em suspensão, um protocolo semelhante foi utilizado, contendo, no entanto, um passo anterior de separação da parede celular por meio de maceração e precipitação em glicerol 15%. Usando colmos da mesma idade, dois meses, um protocolo não destrutivo foi testado com base na infiltração a vácuo dos tecidos nos mesmos sais já descritos, 0,2 M de CaCl2 e 2 M de LiCl, e posterior centrifugação. Duas repetições foram usadas nos experimentos com plantas de dois meses de idade, e três, no caso de células em suspensão. As amostras complexas foram digeridas, fracionadas e seqüenciadas por espectrometria de massas, utilizando o equipamento SYNAPT G2HDMS acoplado ao cromatógrafo nanoACQUITY, ambos da Waters. Os peptídeos foram processadas utilizando ProteinLynx 2,5 comparando com a base de dados de ESTs traduzidos da cana. Utilizando programas de bioinformática, como Blast2GO, foi possível encontrar a anotação e classificação de proteínas semelhantes. Apenas proteínas igualmente encontradas em todas as repetições foram consideradas na análise principal. SignalP, WolfPSORT, TargetP, TMHMM e Predotar foram softwares utilizados para prever a localização subcelular, tanto para ESTs como proteínas, e apenas as proteínas preditas para serem secretadas por dois ou mais programas foram consideradas como proteínas de parede celular. Ao todo, 157 SAS diferentes relacionados à parede celular da cana foram encontrados. Dentre eles, 101 diferentes proteínas de parede foram caracterizadas em oito classes funcionais. O método baseado na infiltração a vácuo mostrou-se o mais eficiente, uma vez que apresentou quase metade, 48,84%, das proteínas preditas para serem secretadas, o que é um bom valor quando comparado com outros estudos. A maioria das proteínas secretadas estava relacionada com o metabolismo lipídico, como proteínas de transporte de lípidos, oxido-redutases, tais como peroxidases, enzimas modificadoras da parede, como as glicosil-hidrolases, proteases, proteínas com domínios de interação, proteínas sinalizadoras, entre outras. Os resultados estão de acordo com o papel que se espera da matriz extracelular no metabolismo de polissacarídeos e fenômenos de sinalização. Portanto, este trabalho forneceu informações valiosas sobre a parede celular da cana, tornando possível a utilização desses dados em futuros estudos para otimizar a produção de etanol celulósico.
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Al-Bar, Omar Abdulrahman Mostafa. "Modified amino acids and peptides as potential inhibitors of bacterial cell wall biosynthesis." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303364.
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Azencott, Harold R. "Influence of the cell wall on intracellular delivery by electroporation and acoustic cavitation." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/11294.
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Torres, Marco Tulio Rincon. "Cellulosome organisation of plant cell wall degrading enzymes in Ruminococcus flavefaciens 17." Thesis, University of Aberdeen, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327013.
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Vicre, Maїté. "Cell wall involvement in desiccation tolerance in the resurrection plant Craterostigma wilmsii." Doctoral thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/8774.
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Bibliography: leaves 92-129.Resurrection plants have the unique capacity to revive from an air-dried state. In order to cope with desiccation, resurrection plants have to overcome a number of stresses, mechanical stress being one. This occurs when the cytoplasm shrinks creating tension between the plasma membrane and the cell wall. In leaves of the Craterostigma species, an extensive shrinkage occurs during drying as well as a considerable wall folding. It is thought that this folding is a well controlled process rather than a simple collapse and that the ability of the wall to fold is important for the viability of the tissues upon drying. The aim of this study was to characterize the cell wall architecture and composition in hydrated and dry leaves of C. wilmsii using microscopical and biochemical techniques. Calcium and hormone contents were also determined during drying. The development of anhydrous fixation for microscopy confirmed the important folding of the wall previously observed with chemical fixation. Using immunocytochemical techniques and a variety of well characterized antibodies, the nature and composition of wall polymers was investigated. There was nothing unusual in the wall composition of C. wilmsii leaves as compared with other dicotyledonous plants. The results show a significant increase of the hemicellulosic polysaccharide xyloglucan and of the unesterified pectins during drying with levels declining again during rehydration. In contrast no increase was observed in others polysaccharides such as ß (1-4) galactans and methylesterified pectins. Biochemical analysis allowed further characterization of cell wall composition of C. wilmsii. The data demonstrate marked changes in the pectic and hemicellulosic wall fraction from dry plants compared to hydrated ones. The most conspicuous change was a decrease in glucose content in the hemicellulose fraction of the dry plant. Together these findings show that dehydration causes important alteration of polysaccharides content in the cell wall of C. wilmsii. Such modifications might be involved in the modulation of the mechanical properties of the wall during dehydration. Furthermore calcium ions content was shown to increase in the cell wall of dry plants, this could also have a role in stabilizing the wall architecture. All these alterations might be under the control of auxin, an hormone whose content was shown to increase during dehydration.
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Ramakrishna, Priya. "Unraveling the role of cell wall remodeling factors in Arabidopsis root development." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43301/.
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Lateral roots are a key component of the plant root system architecture that help anchorage in soil and acquisition of water and nutrients. In the dicot Arabidopsis, lateral roots initiate post-embryonically from a specialised set of cells at the xylem pole of the pericycle cell layer termed ‘founder cells (FC)’, overlaid by three distinct tissue layers – endodermis, cortex, epidermis. The FCs undergo a coordinated series of asymmetric cell divisions (ACD) to form a primordium that grows and emerges through these overlying layers as a mature lateral root. Different auxin signaling modules, as well as tight regulation of the cell geometry are important during early organogenesis. In this study, we were interested to identify molecular components that influence cell wall remodeling properties and cell geometry in the FC and regulates asymmetric cell division during early lateral root initiation. Transcriptomic analysis of FCs (De Smet et al., 2008) identified a candidate gene EXPANSINA1 (EXPA1) of expansin superfamily, known for their unique ability to alter linkage between the cell wall polymers and cause wall loosening. In vivo expression studies showed that EXPA1 is expressed in FCs prior asymmetric cell division. The mutant expa1-1 exhibits perturbed ACD with a delay in kinetics of primordia from Stage I to II, loss in radial expansion of FCs in response to auxin which is important for organised formative divisions. To understand if these defects are due to altered properties of the cell wall, and role of auxin in this process, we developed an optimised technique to study the chemical properties of the FC cell wall junctions based on confocal Raman spectroscopy. This showed altered interactions in expa1-1 between the major cell wall polymers xyloglucans and pectins locally in the pericycle cell wall upon auxin treatment, that could influence cell geometry during early lateral root development. Additionally, sugar monomer analysis of digested whole roots showed interesting alterations in representative global wall sugar levels in the root which although diluted due to lack of tissue specificity warrants further study. In conclusion, the combination of molecular and biochemical analyses reveals that auxin dependent regulation of EXPA1 plays an important role in lateral root FC and is required for organised asymmetric cell division.