scholarly journals Small Molecule Probes for Plant Cell Wall Polysaccharide Imaging

2012 ◽  
Vol 3 ◽  
Author(s):  
Ian S. Wallace ◽  
Charles T. Anderson
2021 ◽  
Vol 22 (6) ◽  
pp. 3077
Author(s):  
Zhenzhen Hao ◽  
Xiaolu Wang ◽  
Haomeng Yang ◽  
Tao Tu ◽  
Jie Zhang ◽  
...  

Plant cell wall polysaccharides (PCWP) are abundantly present in the food of humans and feed of livestock. Mammalians by themselves cannot degrade PCWP but rather depend on microbes resident in the gut intestine for deconstruction. The dominant Bacteroidetes in the gut microbial community are such bacteria with PCWP-degrading ability. The polysaccharide utilization systems (PUL) responsible for PCWP degradation and utilization are a prominent feature of Bacteroidetes. In recent years, there have been tremendous efforts in elucidating how PULs assist Bacteroidetes to assimilate carbon and acquire energy from PCWP. Here, we will review the PUL-mediated plant cell wall polysaccharides utilization in the gut Bacteroidetes focusing on cellulose, xylan, mannan, and pectin utilization and discuss how the mechanisms can be exploited to modulate the gut microbiota.


2017 ◽  
Vol 173 ◽  
pp. 508-518 ◽  
Author(s):  
Cesar A.G. Beatrice ◽  
Natalia Rosa-Sibakov ◽  
Martina Lille ◽  
Nesli Sözer ◽  
Kaisa Poutanen ◽  
...  

Soft Matter ◽  
2016 ◽  
Vol 12 (5) ◽  
pp. 1534-1549 ◽  
Author(s):  
Marta Martínez-Sanz ◽  
Michael J. Gidley ◽  
Elliot P. Gilbert

SANS data of bacterial cellulose and its composites with plant cell wall polysaccharides can be described by a core–shell model which accounts for the distinct solvent accessibility to the ribbons' inner/outer regions.


2019 ◽  
Author(s):  
Ryan J. Protzko ◽  
Christina A. Hach ◽  
Samuel T. Coradetti ◽  
Magdalena A. Hackhofer ◽  
Sonja Magosch ◽  
...  

AbstractBiorefining of renewable feedstocks is one of the most promising routes to replace fossil-based products. Since many common fermentation hosts, such asSaccharomyces cerevisiae, are naturally unable to convert many component plant cell wall polysaccharides, the identification of organisms with broad catabolism capabilities represents an opportunity to expand the range of substrates used in fermentation biorefinery approaches. The red basidiomycete yeastRhodosporidium toruloidesis a promising and robust host for lipid and terpene derived chemicals. Previous studies demonstrated assimilation of a range of substrates, from C5/C6-sugars to aromatic molecules similar to lignin monomers. In the current study, we analyzedR. toruloidespotential to assimilate D-galacturonic acid, a major sugar in many pectin-rich agricultural waste streams, including sugar beet pulp and citrus peels. D-galacturonic acid is not a preferred substrate for many fungi, but its metabolism was found to be on par with D-glucose and D-xylose inR. toruloides. A genome-wide analysis by combined RNAseq/RB-TDNAseq revealed those genes with high relevance for fitness on D-galacturonic acid. WhileR. toruloideswas found to utilize the same non-phosphorylative catabolic pathway known from ascomycetes, the maximal velocities of several enzymes exceeded those previously reported. In addition, an efficient downstream glycerol catabolism and a novel transcription factor were found to be important for D-galacturonic acid utilization. These results set the basis for use ofR. toruloidesas a potential host for pectin-rich waste conversions and demonstrate its suitability as a model for metabolic studies in basidiomycetes.ImportanceThe switch from the traditional fossil-based industry to a green and sustainable bio-economy demands the complete utilization of renewable feedstocks. Many currently used bio-conversion hosts are unable to utilize major components of plant biomass, warranting the identification of microorganisms with broader catabolic capacity and characterization of their unique biochemical pathways. D-galacturonic acid is a plant component of bio-conversion interest and is the major backbone sugar of pectin, a plant cell wall polysaccharide abundant in soft and young plant tissues. The red basidiomycete and oleaginous yeastRhodosporidium toruloideshas been previously shown to utilize a range of sugars and aromatic molecules. Using state-of-the-art functional genomic methods, physiological and biochemical assays, we elucidated the molecular basis underlying the efficient metabolism of D-galacturonic acid. This study identifies an efficient pathway for uronic acid conversion to guide future engineering efforts, and represents the first detailed metabolic analysis of pectin metabolism in a basidiomycete fungus.


2019 ◽  
Vol 85 (23) ◽  
Author(s):  
Silvia Hüttner ◽  
Anikó Várnai ◽  
Dejan M. Petrović ◽  
Cao Xuan Bach ◽  
Dang Thi Kim Anh ◽  
...  

ABSTRACT The thermophilic biomass-degrader Malbranchea cinnamomea exhibits poor growth on cellulose but excellent growth on hemicelluloses as the sole carbon source. This is surprising considering that its genome encodes eight lytic polysaccharide monooxygenases (LPMOs) from auxiliary activity family 9 (AA9), enzymes known for their high potential in accelerating cellulose depolymerization. We characterized four of the eight (M. cinnamomea AA9s) McAA9s, namely, McAA9A, McAA9B, McAA9F, and McAA9H, to gain a deeper understanding about their roles in the fungus. The characterized McAA9s were active on hemicelluloses, including xylan, glucomannan, and xyloglucan, and furthermore, in accordance with transcriptomics data, differed in substrate specificity. Of the McAA9s, McAA9H is unique, as it preferentially cleaves residual xylan in phosphoric acid-swollen cellulose (PASC). Moreover, when exposed to cellulose-xylan blends, McAA9H shows a preference for xylan and for releasing (oxidized) xylooligosaccharides. The cellulose dependence of the xylan activity suggests that a flat conformation, with rigidity similar to that of cellulose microfibrils, is a prerequisite for productive interaction between xylan and the catalytic surface of the LPMO. McAA9H showed a similar trend on xyloglucan, underpinning the suggestion that LPMO activity on hemicelluloses strongly depends on the polymers’ physicochemical context and conformation. Our results support the notion that LPMO multiplicity in fungal genomes relates to the large variety of copolymeric polysaccharide arrangements occurring in the plant cell wall. IMPORTANCE The Malbranchea cinnamomea LPMOs (McAA9s) showed activity on a broad range of soluble and insoluble substrates, suggesting their involvement in various steps of biomass degradation besides cellulose decomposition. Our results indicate that the fungal AA9 family is more diverse than originally thought and able to degrade almost any kind of plant cell wall polysaccharide. The discovery of an AA9 that preferentially cleaves xylan enhances our understanding of the physiological roles of LPMOs and enables the use of xylan-specific LPMOs in future applications.


2021 ◽  
Author(s):  
Florian J Kraemer ◽  
China Lunde ◽  
Moritz Koch ◽  
Benjamin M Kuhn ◽  
Clemens Ruehl ◽  
...  

Abstract The presence of mixed-linkage (1,3;1,4)-β-D-glucan (MLG) in plant cell walls is a key feature of grass species such as cereals, the main source of calorie intake for humans and cattle. Accumulation of this polysaccharide involves the coordinated regulation of biosynthetic and metabolic machineries. While several components of the MLG biosynthesis machinery have been identified in diverse plant species, degradation of MLG is poorly understood. In this study, we performed a large-scale forward genetic screen for maize (Zea mays) mutants with altered cell wall polysaccharide structural properties. As a result, we identified a maize mutant with increased MLG content in several tissues, including adult leaves and senesced organs, where only trace amounts of MLG are usually detected. The causative mutation was found in the GRMZM2G137535 gene, encoding a GH17 licheninase as demonstrated by an in vitro activity assay of the heterologously expressed protein. In addition, maize plants overexpressing GRMZM2G137535 exhibit a 90% reduction in MLG content, indicating that the protein is not only required, but its expression is sufficient to degrade MLG. Accordingly, the mutant was named MLG hydrolase 1 (mlgh1). mlgh1 plants show increased saccharification yields upon enzymatic digestion. Stacking mlgh1 with lignin-deficient mutations results in synergistic increases in saccharification. Time profiling experiments indicate that wall MLG content is modulated during day/night cycles, inversely associated with MLGH1 transcript accumulation. This cycling is absent in the mlgh1 mutant, suggesting that the mechanism involved requires MLG degradation, which may in turn regulate MLGH1 gene expression.


2002 ◽  
Vol 68 (4) ◽  
pp. 1556-1560 ◽  
Author(s):  
Alinda A. Hasper ◽  
Ester Dekkers ◽  
Marc van Mil ◽  
Peter J. I. van de Vondervoort ◽  
Leo H. de Graaff

ABSTRACT A novel gene, eglC, encoding an endoglucanase, was cloned from Aspergillus niger. Transcription of eglC is regulated by XlnR, a transcriptional activator that controls the degradation of polysaccharides in plant cell walls. EglC is an 858-amino-acid protein and contains a conserved C-terminal cellulose-binding domain. EglC can be classified in glycoside hydrolase family 74. No homology to any of the endoglucanases from Trichoderma reesei was found. In the plant cell wall xyloglucan is closely linked to cellulose fibrils. We hypothesize that the EglC cellulose-binding domain anchors the enzyme to the cellulose chains while it is cleaving the xyloglucan backbone. By this action it may contribute to the degradation of the plant cell wall structure together with other enzymes, including hemicellulases and cellulases. EglC is most active towards xyloglucan and therefore is functionally different from the other two endoglucanases from A. niger, EglA and EglB, which exhibit the greatest activity towards β-glucan. Although the mode of action of EglC is not known, this enzyme represents a new enzyme function involved in plant cell wall polysaccharide degradation by A. niger.


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