Xyloglucan Research Articles

Whole Exome Sequencing-Based Identification of a Novel Gene Involved in Root Hair Development in Barley (Hordeum vulgare L.).

Root hairs play a crucial role in anchoring plants in soil, interaction with microorganisms and nutrient uptake from the rhizosphere. In contrast to Arabidopsis, there is a limited knowledge of root hair morphogenesis in monocots, including barley (Hordeum vulgare L.). We have isolated barley mutant rhp1.e with an abnormal root hair phenotype after chemical mutagenesis of spring cultivar ‘Sebastian’. The development of root hairs was initiated in the mutant but inhibited at the very early stage of tip growth. The length of root hairs reached only 3% of the length of parent cultivar. Using a whole exome sequencing (WES) approach, we identified G1674A mutation in the HORVU1Hr1G077230 gene, located on chromosome 1HL and encoding a cellulose synthase-like C1 protein (HvCSLC1) that might be involved in the xyloglucan (XyG) synthesis in root hairs. The identified mutation led to the retention of the second intron and premature termination of the HvCSLC1 protein. The mutation co-segregated with the abnormal root hair phenotype in the F2 progeny of rhp1.e mutant and its wild-type parent. Additionally, different substitutions in HORVU1Hr1G077230 were found in four other allelic mutants with the same root hair phenotype. Here, we discuss the putative role of HvCSLC1 protein in root hair tube elongation in barley.

XYLOGLUCAN CONJUGATED FUNCTIONALIZED GRAPHENE OXIDE AS A NANO CARRIER SYSTEM FOR pH RESPONSIVE TARGETED DRUG DELIVERY OF FUCOIDAN

Objective: Marine polysaccharides are materializing in the field of biomedicine owing to its promising properties, including high biocompatibility, excellent biodegradability, nontoxic nature, abundance and low cost. Fucoidan (FU), a sulphated marine polysaccharide extracted from brown seaweed, shows a promising application prospect as an anticancer model drug. In order to enhance the stability, biocompatibility and drug loading capacity, xyloglucan was chosen as a targeting ligand, conjugated onto the surface of chitosan functionalized graphene oxide for targeted delivery of fucoidan. Methods: Firstly, Graphene oxide (GO) was prepared by modified Hummer’s method and functionalized with chitosan (CS) via amidation process, further conjugated with xyloglucan (XG). The resulting conjugate, GO-CS-XG, was used to deliver fucoidan through a nanocarrier drug delivery method. The developed GO-CS-XG-FU nanosystem was analyzed for its physiochemical characterization, morphology, hemolytic activity, anti-inflammatory and anticancer activity. Results: The FU loading efficiency and capacity were 75.7% and 83.4%, respectively. XG ligands on the nanoparticle may lead the nanoparticles to actively target cancer cells. Hemolytic activity of the FU-loaded GO-CS-XG nanosystem shows negligible activity, thus making it a potential candidate for biomedical applications. In vitro drug release analysis of FU from GO-CS-XG was lesser at physiological pH but under acidic conditions, it was significantly increased. Results of in vitro cell viability studies indicate that the efficiency of fucoidan was improved upon conjugation with the nanosystem (GO-CS-XG) against human histiocytic lymphoma (U 937) cell line. Conclusion: As a result, we propose a new multifunctional graphene-based targeted platform by using xyloglucan polysaccharide as targeting nanomaterial for pH-responsive anticancer drug delivery with high efficacy.

Improved adhesion properties of natural rubber-based pressure-sensitive adhesives by incorporating particulate fillers

A new concept of producing natural rubber (NR) based pressure-sensitive adhesive (PSA) using solid particles relatively at a low-cost as tack enhancer has been proposed. The effect of tack enhancer (i.e., xyloglucan (XG), rice flour (RF), calcium carbonate (CaCO3), and silica (SiO2)) on the adhesion properties of the PSA was investigated. Moreover, stress relaxation, tan δ, initial plasticity (Po), and molecular weight of NR which relates to the adhesion properties were also determined. The study found that XG, RF, and SiO2 can be used as tack enhancers for NR-based PSA. The obtained PSA from those tack enhancers can adhere and peel off on a polypropylene (PP) substrate without any adhesive residue. An increase in the adhesion properties of NR-based PSA can be explained by the effect of fillers on the viscoelastic properties and molecular weight of the PSA. Stress relaxation and molecular weight of the NR-based PSA were significantly found to be decreased, while the tan δ was increased by the addition of particulate tack enhancers compared to the masticated neat NR. NR-based PSA with the highest peel strength (2.11 × 102 N/m) was successfully developed by using XG (40 phr). The NR-based PSA with XG was also showed the ability to resist the unfavorable aged hardening of the NR-based PSA in 180 days.

A novel natural rubber pressure sensitive adhesive patch amended with cinnamon oil for preserving bakery product

Novel pressure sensitive adhesive natural rubber (NR-PSA) patch incorporated with cinnamon oil (CO) and xyloglucan (XG) was prepared to study the effects on mechanical properties, antimicrobial activity, thermal stability, release rate, and shelf life extension of banana cake. The mechanical property test revealed that the contents of CO (8, 10, 15, 20, and 40 μL/patch) did not significantly affect both T-peel and shear strength of NR-PSA/cinnamon oil (NR-PSA/CO) patch. However, CO enhanced the T-peel by 50 % compared to the control patch (without CO). The antimicrobial efficacy was verified against Staphylococcus aureus, Escherichia coli, and Aspergillus niger. At 40 μL of incorporated CO, the patch prolonged the storage life of banana cake for 4 days at ambient temperature relative to the control sample. The release of CO from the patch was studied at 75 % relative humidity (RH). The highest release rate was observed at the first 10 days, and slightly increased up to 45 % after 40 days of the test. These findings indicated a potential of using NR-PSA/CO patch to extend the shelf life of bakery products.

Formulation and In-Vitro Evaluation of Meloxicam Solid Dispersion using Natural Polymers.

Meloxicam (MLX) is non-steroidal anti -inflammatory, poorly water soluble, highly permeable drug and the rate of its oral absorption is often controlled by the dissolution rate in the gastrointestinal tract. Solid dispersion (SD) is an effective technique for enhancing the solubility and dissolution rate of such drug.
 The present study aims to enhance the solubility and the dissolution rate of MLX by SD technique by solvent evaporation method using sodium alginate (SA), hyaluronic acid (HA), collagen and xyloglucan (XG) as gastro-protective hydrophilic natural polymers.
 Twelve formulas were prepared in different drug: polymer ratios and evaluated for their, percentage yield, drug content, water solubility, dissolution, crystal lattice using powder X-ray diffraction (PXRD) and studies and Fourier Transform Infrared Spectroscopy (FTIR) for determination the drug-polymer interaction.
 All the prepared showed improvement of drug solubility except that prepared with HA. The best result was obtained with formula SD1 (MLX: SA 1:1) that showed a high percentage yield (97), high drug content (97.4±0.05) and increase in solubility compared to solubility of pure MLX with improved dissolution rate. the PXRD study revealed the conversion of the drug to amorphous form without chemical interaction according to FTIR results

Ancient origin of fucosylated xyloglucan in charophycean green algae

The charophycean green algae (CGA or basal streptophytes) are of particular evolutionary significance because their ancestors gave rise to land plants. One outstanding feature of these algae is that their cell walls exhibit remarkable similarities to those of land plants. Xyloglucan (XyG) is a major structural component of the cell walls of most land plants and was originally thought to be absent in CGA. This study presents evidence that XyG evolved in the CGA. This is based on a) the identification of orthologs of the genetic machinery to produce XyG, b) the identification of XyG in a range of CGA and, c) the structural elucidation of XyG, including uronic acid-containing XyG, in selected CGA. Most notably, XyG fucosylation, a feature considered as a late evolutionary elaboration of the basic XyG structure and orthologs to the corresponding biosynthetic enzymes are shown to be present in Mesotaenium caldariorum.

ENHANCEMENT OF THE SOLUBILITY OF FAMOTIDINE SOLID DISPERSION USING NATURAL POLYMER BY SOLVENT EVAPORATION

Objective: The aims of the study to enhance solubility and dissolution of famotidine using natural polymer. Solubility study of a drug is one of the contributing factors of its oral bioavailability. The formulation of poorly soluble drugs for oral delivery presents a challenge to the formulation technologists.
 Methods: The present study has shown that it is possible to raise the solubility for poorly soluble drugs like famotidine, by preparing solid dispersion using natural water-soluble polymer (xyloglucan and hyaluronic acid) as solubilizer through solvent evaporation method. Physical mixture and solid dispersion of famotidine with xyloglucan (XG) or hyaluronic acid in a ratio of 1:1, 1:2, 1:3 were prepared. Solubility study, drug content, dissolution profile and compatibility study were performed for famotidine in solid dispersions XS1, XS2, XS3, HS4, HS5, HS6 as well as in physical mixtures at a ratio 1:1 for both polymer (XG and hyaluronic acid).
 Results: It was observed that solid dispersions of each drugs showed an increase in dissolution rate in comparison with its pure drug in the ratio of 1:1 (Drug: carrier). It can be concluded that with the care and proper use of xyloglucan, the solubility of drugs poorly soluble can be improved.
 The prepared solid dispersion showed improvement of drug solubility in all prepared formulas. The best result was obtained with formula XS1 (famotidine: xyloglucan at ratio 1:1) that showed 26 fold increase in solubility compared to the solubility of pure drug.
 Conclusion: The natural solid dispersion, increased wettability and reduced crystallinity of the drug which leads to improving solubility and dissolution.

Exploring the Effective Utilization of Shallot Stalk Waste and Tamarind Seed for Packaging Film Preparation

Owing to the increased generation of agricultural bio-waste especially onion solid waste and its impact on environment, the present study mainly focused on the utilization of selected waste streams such as shallot stalk and tamarind seed for development of packaging films which can be used as an alternative to plastic films. Different extraction methods were used for the extraction of xyloglucan (XG). The condition of selected extraction method was optimized by central composite design using response surface methodology. The shallot stalk powder (SSP) packaging film was prepared with extracted XG by casting method. The properties of xyloglucan and SSP packaging film were analyzed and it was compared with commercial pectin based films. Microwave-assisted extraction (MAE) provided a high yield of 21.75% of xyloglucan compared to other methods with optimum process parameters as power level 400 W, liquid to solid ratio 99.43 ml/g, temperature 83.23 °C and time 14.29 min, respectively. The SSP films have less water vapor permeability 1.06 × 10−10−1.49 × 10−10 g/m. s. Pa, high total phenolic content 63.76–69.23 mg/g and antioxidant capacity 23.47–24.09% compared to the control films. Thus, the study provides the rational for effective utilization of not only shallot stalk waste, but also other onion solid waste includes flower, petiole and skin in food packaging applications.

Interaction of cellulose and xyloglucan influences in vitro fermentation outcomes

To investigate the effects of interactions between cellulose and xyloglucan (XG) on in vitro fermentation, a composite of bacterial cellulose (BC) incorporating XG during pellicle formation (BCXG), was fermented using a human faecal inoculum, and compared with BC, XG and a mixture (BC&XG) physically blended to have the same BC to XG ratio of BCXG. Compared to individual polysaccharides, the fermentation extent of BC and fermentation rate of XG were promoted in BC&XG. XG embedded in the BCXG composite was degraded less than in BC&XG, while more cellulose in BCXG was fermented than in BC&XG. This combination explains the similar amount of short chain fatty acid production noted throughout the fermentation process for BCXG and BC&XG. Microbial community dynamics for each substrate were consistent with the corresponding polysaccharide degradation. Thus, interactions between cellulose and XG are shown to influence their fermentability in multiple ways.

Xyloglucan endotransglycosylase/hydrolase increases tightly-bound xyloglucan and chain number but decreases chain length contributing to the defense response that Glycine max has to Heterodera glycines.

The Glycine max xyloglucan endotransglycosylase/hydrolase (EC 2.4.1.207), GmXTH43, has been identified through RNA sequencing of RNA isolated through laser microdissection of Heterodera glycines-parasitized root cells (syncytia) undergoing the process of defense. Experiments reveal that genetically increasing XTH43 transcript abundance in the H. glycines-susceptible genotype G. max[Williams 82/PI 518671] decreases parasitism. Experiments presented here show decreasing XTH43 transcript abundance through RNA interference (RNAi) in the H. glycines-resistant G. max[Peking/PI 548402] increases susceptibility, but it is unclear what role XTH43 performs. The experiments presented here show XTH43 overexpression decreases the relative length of xyloglucan (XyG) chains, however, there is an increase in the amount of those shorter chains. In contrast, XTH43 RNAi increases XyG chain length. The experiments show that XTH43 has the capability to function, when increased in its expression, to limit XyG chain extension. This outcome would likely impair the ability of the cell wall to expand. Consequently, XTH43 could provide an enzymatically-driven capability to the cell that would allow it to limit the ability of parasitic nematodes like H. glycines to develop a feeding structure that, otherwise, would facilitate parasitism. The experiments presented here provide experimentally-based proof that XTHs can function in ways that could be viewed as being able to limit the expansion of the cell wall.

Active Bio-Based Pressure-Sensitive Adhesive Based Natural Rubber for Food Antimicrobial Applications: Effect of Processing Parameters on Its Adhesion Properties.

A novel active bio-based pressure-sensitive adhesive incorporating cinnamon oil (Bio-PSA/CO) obtained from the mixture of natural rubber (NR), xyloglucan (XG), and cinnamon oil (CO) for food antimicrobial applications were successfully developed by using a two-roll mill mixer. The effect of the main process factors (i.e., nip gap and mastication time) and XG content on the adhesion properties of the obtained PSA were investigated with different coated substrates including kraft paper, nylon film, polypropylene (PP) film, and aluminum foil (Al). The results suggested that the developed NR-PSA/CO could be applied well to all types of substrate materials. Peel strength and shear strength of the NR-PSA/CO with all substrate types were in the ranges of ~0.03 × 102–5.64 × 102 N/m and ~0.24 × 104–9.50 × 104 N/m2, respectively. The proper processed condition of the NR-PSA/CO was represented with a nip gap of 2 mm and a mastication time of 15 min. An increase in XG content up to 40–60 phr can improve the adhesion properties of the adhesive. The resulting material could be used as an active sticky patch to extend the shelf-life of food in a closed packaging system. The shelf-life of the food samples (banana cupcake) could be extended from 4 to 9 days with NR-PSA/CO patch.

Cellulose Nanofibrils/Xyloglucan Bio-Based Aerogels with Shape Recovery.

Bio-based aerogels containing cellulose nanofibrils (CNFs) are promising materials due to the inherent physical properties of CNF. The high affinity of cellulose to plant hemicelluloses (xyloglucan, xylan, pectin) is also an opportunity to develop biomaterials with new properties. Here, we prepared aerogels from gelled dispersions of CNFs and xyloglucan (XG) at different ratios by using a freeze-casting procedure in unidirectional (UD) and non-directional (ND) manners. As showed by rheology analysis, CNF and CNF/XG dispersions behave as true gels. We investigated the impact of the freezing procedure and the gel’s composition on the microstructure and the water absorption properties. The introduction of XG greatly affects the microstructure of the aerogel from lamellar to cellular morphology. Bio-based aerogels showed high water absorption capacity with shape recovery after compression. The relation between morphology and aerogel compositions is discussed.

Long-term safety and efficacy study of a medical device containing xyloglucan, pea protein reticulated with tannins and xylo-oligosaccharides, in patients with diarrhoea-predominant irritable bowel syndrome.

Background:Irritable bowel syndrome with diarrhoea (IBS-D) is a frequent problem associated with a significant socioeconomic implication. Increased gut permeability is an important pathophysiological mechanism. A medical device containing xyloglucan (XG), pea protein and tannins (PPT) from grape-seed extract, and xylo-oligosaccharides (XOS) has proven restoration of intestinal barrier function. Our objective was to evaluate the efficacy and safety of treatment with the medical device XG + PPT + XOS (XG-PPT-XOS) in adult patients with IBS-D in a clinical setting for 6 months.Material and methods:This was a multicentre, open-label, prospective, observational study conducted to evaluate long-term safety and efficacy of XG-PPT-XOS. IBS-D adult patients (Rome IV criteria) were included and received two tablets twice daily for 6 months. IBS Symptom Severity Score (IBS-SSS) and bowel habit were registered at baseline and monthly, until the end of follow up. Efficacy was evaluated by comparison of mean scores at each time point.Results:50 patients were included, of which 19 completed the 6 months. IBS-SSS score decreased from 312.2 ± 82.2 to 213.6 ± 109.9 (p < 0.0001) at 1 month and 192.0 ± 108.9 at the last visit completed; diarrhoea score decreased from 45.6 ± 17.9 to 25.7 ± 17.7 and 25.3 ± 17.2 at 1 month and at the last visit completed, respectively. Pain score decreased from 107.8 ± 49.9 at baseline to 73.2 ± 57.3 (p < 0.0001) at 1 month and bloating score from 56.4 ± 28.8 at baseline to 42.8 ± 32.6 (p < 0.001) at 1 month, reaching 62.4 ± 56.0 and 40.4 ± 34.3, respectively, at the last visit completed. Adverse effects were mild and mostly not related to treatment.Conclusion:Treating IBS-D patients with XG-PPT-XOS is effective and safe in the long term within a clinical setting, improving all IBS-D symptoms from the first month of treatment and showing a sustained response over the term of therapy.

Entropy drives the adsorption of xyloglucan to cellulose surfaces – A molecular dynamics study

The adsorption of nonionic polymers to cellulose is of large importance both in the plant cell wall during synthesis and for the development of sustainable materials from wood. Here, the thermodynamics of adsorption of the polysaccharide xyloglucan (XG) to both native and chemically modified cellulose with carboxyl groups was investigated using molecular dynamics simulations. The free energy of adsorption was calculated as the potential of mean force between an XG oligomer and model cellulose surfaces in a range of temperatures from 298 K to 360 K. It was found that the adsorption near room temperature is an endothermic process dominated by the entropy of released interfacial water molecules. This was corroborated by quantitative assessment of the absolute entropy per water molecule both at the interface and in the bulk. In the case of native cellulose, the adsorption became exothermic at higher temperatures, while the relatively strong interactions between water and the charged groups of the oxidized cellulose impede such a transition. The results also indicate that the extraction of strongly associated hemicelluloses would be facilitated by low temperature.

Bioinspired Thermoresponsive Xyloglucan–Cellulose Nanocrystal Hydrogels

Thermoresponsive hydrogels present unique properties, such as tunable mechanical performance or changes in volume, which make them attractive for applications including wound healing dressings, drug delivery vehicles, and implants, among others. This work reports the implementation of bioinspired thermoresponsive hydrogels composed of xyloglucan (XG) and cellulose nanocrystals (CNCs). Starting from tamarind seed XG (XGt), thermoresponsive XG was obtained by enzymatic degalactosylation (DG-XG), which reduced the galactose residue content by ∼50% and imparted a reversible thermal transition. XG with native composition and comparable molar mass to DG-XG was produced by an ultrasonication treatment (XGu) for a direct comparison of behavior. The hydrogels were prepared by simple mixing of DG-XG or XGu with CNCs in water. Phase diagrams were established to identify the ratios of DG-XG or XGu to CNCs that yielded a viscous liquid, a phase-separated mixture, a simple gel, or a thermoresponsive gel. Gelation occurred at a DG-XG or XGu to CNC ratio higher than that needed for the full surface coverage of CNCs and required relatively high overall concentrations of both components (tested concentrations up to 20 g/L XG and 30 g/L CNCs). This is likely a result of the increase in effective hydrodynamic volume of CNCs due to the formation of XG-CNC complexes. Investigation of the adsorption behavior indicated that DG-XG formed a more rigid layer on CNCs compared to XGu. Rheological properties of the hydrogels were characterized, and a reversible thermal transition was found for DG-XG/CNC gels at 35 °C. This thermoresponsive behavior provides opportunities to apply this system widely, especially in the biomedical field, where the mechanical properties could be further tuned by adjusting the CNC content.

Plant Xyloglucan Xyloglucosyl Transferases and the Cell Wall Structure: Subtle but Significant.

Plant xyloglucan xyloglucosyl transferases or xyloglucan endo-transglycosylases (XET; EC 2.4.1.207) catalogued in the glycoside hydrolase family 16 constitute cell wall-modifying enzymes that play a fundamental role in the cell wall expansion and re-modelling. Over the past thirty years, it has been established that XET enzymes catalyse homo-transglycosylation reactions with xyloglucan (XG)-derived substrates and hetero-transglycosylation reactions with neutral and charged donor and acceptor substrates other than XG-derived. This broad specificity in XET isoforms is credited to a high degree of structural and catalytic plasticity that has evolved ubiquitously in algal, moss, fern, basic Angiosperm, monocot, and eudicot enzymes. These XET isoforms constitute gene families that are differentially expressed in tissues in time- and space-dependent manners during plant growth and development, and in response to biotic and abiotic stresses. Here, we discuss the current state of knowledge of broad specific plant XET enzymes and how their inherently carbohydrate-based transglycosylation reactions tightly link with structural diversity that underlies the complexity of plant cell walls and their mechanics. Based on this knowledge, we conclude that multi- or poly-specific XET enzymes are widespread in plants to allow for modifications of the cell wall structure in muro, a feature that implements the multifaceted roles in plant cells.

Hierarchical thermoplastic biocomposites reinforced with flax fibres modified by xyloglucan and cellulose nanocrystals

This work is focused on the modification of the interphase zone in short flax fibres / polypropylene (PP) composites by a bio-inspired modification of fibres called “nanostructuration” that uses the adsorption of biomass by-products, i.e. cellulose nanocrystals (CNC) and xyloglucan (XG), to create hierarchical flax fibres. The wettability and interfacial adhesion study reveals a strong decrease in the polar character of CNC modified flax fibres, hence increasing the work of adhesion with PP. Moreover, combining XG/CNC modified interphases with MAPP coupling agent enhances the ultimate mechanical properties of biocomposites with higher tensile strength and work of rupture, and modifies failure mechanisms as revealed by in situ micro-mechanical tensile SEM experiments. Bio-based hierarchical composites inspired by naturally occurring nanostructures open a new path for the development of sustainable composites with enhanced structural properties.

Evaluation of a Product Containing Xyloglucan and Pea Protein on Skin Barrier Permeability

Objective: The skin acts as a mechanical and protective barrier against viral, fungal, and bacterial infections. Skin conditions such as atopic dermatitis and psoriasis are characterized by alterations of the skin barrier, often caused by injury and by bacterial infections. In the last years, non-pharmacological interventions have gained great importance in epidermis-related diseases. Xyloglucan (XG) is a polysaccharide that possesses a “mucin-like” molecular structure that confers mucoadhesive properties, allowing XG-containing formulations to act as a protective barrier for the management of different diseases. Moreover, there is also increasing interest in the use of proteins due to their film-forming features. This study aimed to evaluate the barrier-protective properties of a product containing XG and pea protein (PP) in an in vitro model, assessing its effects on the membrane permeability of keratinocytes infected by Staphylococcus aureus. Methods: HaCaT keratinocytes were pretreated with XG and PP for 3 h and then infected with S. aureus cells (10⁶ bacteria/well) at a multiplicity of infection of 10 for 1 h. The number of bacterial colonies and membrane integrity were measured, respectively. Results: We observed that pretreatment with XG and PP in human HaCaT keratinocytes infected with S. aureus significantly increased trans-epithelial electrical resistance (a marker of skin barrier function) measurement, reduced lucifer yellow (a marker of membrane integrity) permeation across the monolayer, and released lactate dehydrogenase (a marker of tissue damage). Moreover, XG and PP pretreatment was able to reduce bacterial adherence, avoiding S. aureus infection. Conclusion: In summary, we demonstrated that the product containing XG and PP was able to maintain barrier permeability preserving its integrity, and therefore, it can be considered as an interesting approach for the management of epidermis-related diseases.

Xyloglucan compounded inulin or arabinoxylan against glycometabolism disorder via different metabolic pathways: Gut microbiota and bile acid receptor effects

This study investigated the effects of xyloglucan (XG) compounded inulin and XG compounded arabinoxylan on the hypoglycemic activity of mice fed with high-fat diet (HFD). Forty male ICR/KM mice were randomly divided into four groups, namely, control group, high-fat group, XG and 4% inulin supplemented in a HFD group (HFXI), and XG and 4% arabinoxylan supplemented in a HFD group (HFXA). Results showed that XI and XA supplementation decreased serum glucose level and intestinal disaccharidase activity. XI and XA decreased the level of total bile acid (TBA) in the serum and liver. Fecal TBA excretion was increased in the HFXI group, and XA treatment decreased colon digesta TBA excretion. XI treatment activated liver farnesoid X receptor (FXR) and G protein-coupled receptor 5 (TGR5). Intestinal FXR and TGR5 were activated after XA supplementation. XA increased the abundance of Verrucomicrobia, promoting Akkermansia growth, whereas XI treatment increased the abundance of gut Bifidobacterium.

Xyloglucan Structure Impacts the Mechanical Properties of Xyloglucan-Cellulose Nanocrystal Layered Films-A Buckling-Based Study.

Interactions between polysaccharides, specifically between cellulose and hemicelluloses like xyloglucan (XG), govern the mechanical properties of the plant cell wall. This work aims to understand how XG molecular weight (MW) and the removal of saccharide residues impact the elastic modulus of XG-cellulose materials. Layered sub-micrometer-thick films of cellulose nanocrystals (CNCs) and XG were employed to mimic the structure of the plant cell wall and contained either (1) unmodified XG, (2) low MW XG produced by ultrasonication (USXG), or (3) XG with a reduced degree of galactosylation (DGXG). Their mechanical properties were characterized through thermal shrinking-induced buckling. Elastic moduli of 19 ± 2, 27 ± 1, and 75 ± 6 GPa were determined for XG-CNC, USXG-CNC, and DGXG-CNC films, respectively. The conformation of XG adsorbed on CNCs is influenced by MW, which impacts mechanical properties. To a greater degree, partial degalactosylation, which is known to increase XG self-association and binding capacity of XG to cellulose, increases the modulus by fourfold for DGXG-CNC films compared to XG-CNC. Films were also buckled while fully hydrated by using the thermal shrinking method but applying the heat using an autoclave; the results implied that hydrated films are thicker and softer, exhibiting a lower elastic modulus compared to dry films. This work contributes to the understanding of structure-function relationships in the plant cell wall and may aid in the design of tunable biobased materials for applications in biosensing, packaging, drug delivery, and tissue engineering.