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1.
Carbohydr Polym ; 339: 122256, 2024 Sep 01.
Article En | MEDLINE | ID: mdl-38823922

Recently, the intestinal lymphatic transport based on Peyer's patches (PPs) is emerging as a promising absorption pathway for natural polysaccharides. Herein, the aim of this study is to investigate the PP-based oral absorption of a pectic polysaccharide from Smilax china L. (SCLP), as well as its uptake and transport mechanisms in related immune cells. Taking advantages of the traceability of fluorescently labeled SCLP, we confirmed that SCLP could be absorbed into PPs and captured by their mononuclear phagocytes (dendritic cells and macrophages) following oral administration. Subsequently, the systematic in vitro study suggested that the endocytic mechanisms of SCLP by model mononuclear phagocytes (BMDCs and RAW264.7 cells) mainly involved caveolae-mediated endocytosis, macropinocytosis and phagocytosis. More importantly, SCLP directly binds and interacts with toll-like receptor 2 (TLR2) and galectin 3 (Gal-3) receptor, and was taken up by mononuclear phagocytes in receptor-mediated manner. After internalization, SCLP was intracellularly transported primarily through endolysosomal pathway and ultimately localized in lysosomes. In summary, this work reveals novel information and perspectives about the in vivo fate of SCLP, which will contribute to further research and utilization of SCLP and other pectic polysaccharides.


Peyer's Patches , Smilax , Animals , Mice , RAW 264.7 Cells , Peyer's Patches/metabolism , Smilax/chemistry , Endocytosis , Pectins/chemistry , Pectins/metabolism , Macrophages/metabolism , Macrophages/drug effects , Phagocytosis/drug effects , Phagocytes/metabolism , Phagocytes/drug effects , Toll-Like Receptor 2/metabolism , Mice, Inbred BALB C , Male , Dendritic Cells/metabolism , Dendritic Cells/drug effects , Administration, Oral
2.
Carbohydr Polym ; 339: 122284, 2024 Sep 01.
Article En | MEDLINE | ID: mdl-38823935

Interactions between human gut microbiota and dietary fibres (DF) are influenced by the complexity and diversity of both individual microbiota and sources of DF. Based on 480 in vitro fermentations, a full factorial experiment was performed with six faecal inocula representing two enterotypes and three DF sources with nanometer, micrometer, and millimeter length-scales (apple pectin, apple cell walls and apple particles) at two concentrations. Increasing DF size reduced substrate disappearance and fermentation rates but not biomass growth. Concentrated DF enhanced butyrate production and lactate cross-feeding. Enterotype differentiated final microbial compositions but not biomass or fermentation metabolite profiles. Individual donor microbiota differences did not influence DF type or concentration effects but were manifested in the promotion of different functional microbes within each population with the capacity to degrade the DF substrates. Overall, consistent effects (independent of donor microbiota variation) of DF type and concentration on kinetics of substrate degradation, microbial biomass production, gas kinetics and metabolite profiles were found, which can form the basis for informed design of DF for desired rates/sites and consequences of gut fermentation. These results add further evidence to the concept that, despite variations between individuals, the human gut microbiota represents a community with conserved emergent properties.


Dietary Fiber , Feces , Fermentation , Gastrointestinal Microbiome , Pectins , Pectins/metabolism , Dietary Fiber/metabolism , Gastrointestinal Microbiome/drug effects , Gastrointestinal Microbiome/physiology , Humans , Feces/microbiology , Malus/metabolism , Adult , Male , Female , Bacteria/metabolism , Bacteria/classification , Biomass
3.
Elife ; 132024 Jun 04.
Article En | MEDLINE | ID: mdl-38832933

Modification of pectin, a component of the plant cell wall, is required to facilitate signaling by a RALF peptide, which is essential for many physiological and developmental processes.


Pectins , Signal Transduction , Pectins/metabolism , Pectins/chemistry , Cell Wall/metabolism , Arabidopsis/genetics , Arabidopsis/metabolism , Arabidopsis/growth & development , Arabidopsis Proteins/metabolism , Arabidopsis Proteins/genetics
4.
Microb Biotechnol ; 17(5): e14443, 2024 May.
Article En | MEDLINE | ID: mdl-38722820

Pectin structures have received increasing attention as emergent prebiotics due to their capacity to promote beneficial intestinal bacteria. Yet the collective activity of gut bacterial communities to cooperatively metabolize structural variants of this substrate remains largely unknown. Herein, the characterization of a pectin methylesterase, BpeM, from Bifidobacterium longum subsp. longum, is reported. The purified enzyme was able to remove methyl groups from highly methoxylated apple pectin, and the mathematical modelling of its activity enabled to tightly control the reaction conditions to achieve predefined final degrees of methyl-esterification in the resultant pectin. Demethylated pectin, generated by BpeM, exhibited differential fermentation patterns by gut microbial communities in in vitro mixed faecal cultures, promoting a stronger increase of bacterial genera associated with beneficial effects including Lactobacillus, Bifidobacterium and Collinsella. Our findings demonstrate that controlled pectin demethylation by the action of a B. longum esterase selectively modifies its prebiotic fermentation pattern, producing substrates that promote targeted bacterial groups more efficiently. This opens new possibilities to exploit biotechnological applications of enzymes from gut commensals to programme prebiotic properties.


Carboxylic Ester Hydrolases , Feces , Malus , Pectins , Prebiotics , Malus/microbiology , Pectins/metabolism , Feces/microbiology , Carboxylic Ester Hydrolases/metabolism , Carboxylic Ester Hydrolases/genetics , Fermentation , Humans , Bifidobacterium longum/metabolism , Bifidobacterium longum/enzymology , Gastrointestinal Microbiome , Bifidobacterium/enzymology , Bifidobacterium/metabolism
5.
Int J Mol Sci ; 25(10)2024 May 11.
Article En | MEDLINE | ID: mdl-38791293

The plant cell wall is an actively reorganized network during plant growth and triggered immunity in response to biotic stress. While the molecular mechanisms managing perception, recognition, and signal transduction in response to pathogens are well studied in the context of damaging intruders, the current understanding of plant cell wall rebuilding and active defense strategies in response to plant virus infections remains poorly characterized. Pectins can act as major elements of the primary cell wall and are dynamic compounds in response to pathogens. Homogalacturonans (HGs), a main component of pectins, have been postulated as defensive molecules in plant-pathogen interactions and linked to resistance responses. This research focused on examining the regulation of selected pectin metabolism components in susceptible (rbohD-, Col-0-TuMV) and resistance (rbohF-, rbohD/F-TuMV) reactions. Regardless of the interaction type, ultrastructural results indicated dynamic cell wall rebuilding. In the susceptible reaction promoted by RbohF, there was upregulation of AtPME3 (pectin methylesterase) but not AtPME17, confirmed by induction of PME3 protein deposition. Moreover, the highest PME activity along with a decrease in cell wall methylesters compared to resistance interactions in rbohD-TuMV were noticed. Consequently, the susceptible reaction of rbohD and Col-0 to TuMV was characterized by a significant domination of low/non-methylesterificated HGs. In contrast, cell wall changes during the resistance response of rbohF and rbohD/F to TuMV were associated with dynamic induction of AtPMEI2, AtPMEI3, AtGAUT1, and AtGAUT7 genes, confirmed by significant induction of PMEI2, PMEI3, and GAUT1 protein deposition. In both resistance reactions, a dynamic decrease in PME activity was documented, which was most intense in rbohD/F-TuMV. This decrease was accompanied by an increase in cell wall methylesters, indicating that the domination of highly methylesterificated HGs was associated with cell wall rebuilding in rbohF and rbohD/F defense responses to TuMV. These findings suggest that selected PME with PMEI enzymes have a diverse impact on the demethylesterification of HGs and metabolism as a result of rboh-TuMV interactions, and are important factors in regulating cell wall changes depending on the type of interaction, especially in resistance responses. Therefore, PMEI2 and PMEI3 could potentially be important signaling resistance factors in the rboh-TuMV pathosystem.


Arabidopsis , Cell Wall , Disease Resistance , Pectins , Plant Diseases , Pectins/metabolism , Cell Wall/metabolism , Plant Diseases/genetics , Arabidopsis/metabolism , Arabidopsis/genetics , Arabidopsis/immunology , Gene Expression Regulation, Plant , Arabidopsis Proteins/metabolism , Arabidopsis Proteins/genetics , Potyvirus , Carboxylic Ester Hydrolases/metabolism
6.
Sci Rep ; 14(1): 11454, 2024 05 20.
Article En | MEDLINE | ID: mdl-38769105

This study focuses on pectin covalently linked in cell walls from two sources, apples and carrots, that was extracted using diluted alkali, and it describes changes in the rheological properties of diluted alkali-soluble pectin (DASP) due to enzymatic treatment. Given DASP's richness of rhamnogalacturonan I (RG-I), RG-I acetyl esterase (RGAE), rhamnogalacturonan endolyase (RGL), and arabinofuranosidase (ABF) were employed in various combinations for targeted degradation of RG-I pectin chains. Enzymatic degradations were followed by structural studies of pectin molecules using atomic force microscopy (AFM) as well as measurements of rheological and spectral properties. AFM imaging revealed a significant increase in the length of branched molecules after incubation with ABF, suggesting that arabinose side chains limit RG-I aggregation. Structural modifications were confirmed by changes in the intensity of bands in the pectin fingerprint and anomeric region on Fourier transform infrared spectra. ABF treatment led to a decrease in the stability of pectic gels, while the simultaneous use of ABF, RGAE, and RGL enzymes did not increase the degree of aggregation compared to the control sample. These findings suggest that the association of pectin chains within the DASP fraction may rely significantly on intermolecular interactions. Two mechanisms are proposed, which involve side chains as short-range attachment points or an extended linear homogalacturonan conformation favoring inter-chain interactions over self-association.


Pectins , Rheology , Pectins/chemistry , Pectins/metabolism , Microscopy, Atomic Force , Alkalies/chemistry , Glycoside Hydrolases/metabolism , Glycoside Hydrolases/chemistry , Solubility , Spectroscopy, Fourier Transform Infrared , Daucus carota/chemistry , Polysaccharide-Lyases/metabolism , Polysaccharide-Lyases/chemistry , Cell Wall/chemistry , Cell Wall/metabolism
7.
Food Chem ; 452: 139445, 2024 Sep 15.
Article En | MEDLINE | ID: mdl-38728886

Cell wall disassembly and transcriptomic changes during storage of two fresh-cut chili pepper cultivars displaying contrasting softening rates were investigated. Results showed that Hangjiao No. 2 (HJ-2) softened more rapidly than Lafeng No. 3 (LF-3). Compared with LF-3, HJ-2 had a higher content of WSP, more side chains of RG-I in three pectin fractions, and higher activities of PME, PL, and ß-Gal at day-0. During storage, HJ-2 showed more markable pectin solubilization, more severe degradation in CSP and NSP, and greater loss of side chains from RG-I in three pectin fractions, which were correlated with increased activities of PG and α-L-Af. Furthermore, the higher up-regulation of PG (LOC107870605, LOC107851416) and α-L-Af (LOC107848776, LOC107856612) were screened in HJ-2. In conclusion, the different softening rate between cultivars was not only due to the fundamental differences in pectin structure but also pectin degradation regulated by related enzymes and gene expression levels.


Capsicum , Cell Wall , Food Storage , Gene Expression Profiling , Pectins , Plant Proteins , Polysaccharides , Capsicum/genetics , Capsicum/chemistry , Capsicum/metabolism , Cell Wall/chemistry , Cell Wall/metabolism , Cell Wall/genetics , Polysaccharides/metabolism , Polysaccharides/chemistry , Plant Proteins/genetics , Plant Proteins/metabolism , Pectins/metabolism , Pectins/chemistry , Fruit/chemistry , Fruit/genetics , Fruit/metabolism , Gene Expression Regulation, Plant , Transcriptome
8.
Food Chem ; 452: 139606, 2024 Sep 15.
Article En | MEDLINE | ID: mdl-38744127

In this study, two pectic polysaccharides (PFP-T and PFP-UM) were extracted from fresh passion fruit peels using three-phase partitioning (TPP) and sequential ultrasound-microwave-assisted TPP methods, respectively, and their effects on the in vitro gastrointestinal digestion and fecal fermentation characteristics were examined. The results indicate that gastrointestinal digestion has a minimal effect on the physicochemical and structural characteristics of PFP-T and PFP-UM. However, during in vitro fecal fermentation, both undigested PFP-T and PFP-UM are significantly degraded and utilized by intestinal microorganisms, showing increased the total relative abundance of Firmicutes and Bacteroidota in the intestinal flora. Notably, compared with PFP-UM, PFP-T better promoted the reproduction of beneficial bacteria such as Prevotella, Megasphaera and Dialister, while suppressed the growth of harmful genera including Escherichia-Shigella, producing higher content of short-chain fatty acids. Therefore, our findings suggest that PFP-T derived from passion fruit peel has potential as a dietary supplement for promoting intestinal health.


Bacteria , Digestion , Fermentation , Fruit , Passiflora , Passiflora/chemistry , Passiflora/metabolism , Fruit/chemistry , Fruit/metabolism , Bacteria/metabolism , Humans , Polysaccharides/metabolism , Polysaccharides/chemistry , Pectins/metabolism , Pectins/chemistry , Feces/microbiology , Feces/chemistry , Gastrointestinal Microbiome , Plant Extracts/chemistry , Plant Extracts/metabolism , Models, Biological
9.
J Agric Food Chem ; 72(20): 11652-11662, 2024 May 22.
Article En | MEDLINE | ID: mdl-38738910

Pectin lyases (PNLs) can enhance juice clarity and flavor by degrading pectin in highly esterified fruits, but their inadequate acid resistance leads to rapid activity loss in juice. This study aimed to improve the acid resistance of Aspergillus niger PNL pelA through surface charge design. A modification platform was established by fusing pelA with a protein tag and expressing the fusion enzyme in Escherichia coli. Four single-point mutants were identified to increase the surface charge using computational tools. Moreover, the combined mutant M6 (S514D/S538E) exhibited 99.8% residual activity at pH 3.0. The M6 gene was then integrated into the A. niger genome using a multigene integration system to obtain the recombinant PNL AM6. Notably, AM6 improved the light transmittance of orange juice to 45.3%, which was 8.39 times higher than that of pelA. In conclusion, AM6 demonstrated the best-reported acid resistance, making it a promising candidate for industrial juice clarification.


Aspergillus niger , Fruit and Vegetable Juices , Fungal Proteins , Polysaccharide-Lyases , Aspergillus niger/enzymology , Aspergillus niger/genetics , Fruit and Vegetable Juices/analysis , Polysaccharide-Lyases/genetics , Polysaccharide-Lyases/metabolism , Polysaccharide-Lyases/chemistry , Fungal Proteins/genetics , Fungal Proteins/metabolism , Fungal Proteins/chemistry , Hydrogen-Ion Concentration , Food Handling , Acids/chemistry , Acids/metabolism , Acids/pharmacology , Citrus sinensis/chemistry , Pectins/chemistry , Pectins/metabolism , Enzyme Stability
10.
J Agric Food Chem ; 72(22): 12752-12761, 2024 Jun 05.
Article En | MEDLINE | ID: mdl-38779924

This study investigated the transformation of polyphenols, including free and bound polyphenols during the fermentation of wolfberry juice by Lactobacillus plantarum NCU137. Results indicated that fermentation significantly increased the free polyphenols content and released bound polyphenols, enhancing the antioxidant activity. Analysis showed that there were 19 free polyphenols, mainly scopoletin, pyrogallol, and dihydroferulic acid, and 16 bound polyphenols, especially p-coumaric acid, feruloyl hexoside, and caffeic acid. A significant correlation was observed between the generation and degradation of polyphenols, and specific bound polyphenols peaked during the 24-48 h fermentation. Furthermore, reduced surface roughness and galacturonic acid content in wolfberry residue, along with increased pectinase activity, suggested substantial pectin degradation in the cell wall, which may be associated with the release of polyphenols, due to pectin serving as carriers for bound polyphenols. The fermentation also increased polyphenol oxidase and peroxidase activity, contributing to polyphenol breakdown. These findings provide insights for improving wolfberry juice production.


Antioxidants , Fermentation , Fruit and Vegetable Juices , Fruit , Lactobacillus plantarum , Lycium , Polyphenols , Lactobacillus plantarum/metabolism , Lactobacillus plantarum/chemistry , Polyphenols/metabolism , Polyphenols/chemistry , Antioxidants/metabolism , Antioxidants/chemistry , Fruit and Vegetable Juices/analysis , Fruit/chemistry , Fruit/metabolism , Fruit/microbiology , Lycium/chemistry , Lycium/metabolism , Pectins/metabolism , Pectins/chemistry
11.
Int J Biol Macromol ; 269(Pt 2): 131918, 2024 Jun.
Article En | MEDLINE | ID: mdl-38697418

Polygalacturonases (PGs) can modulate chemistry and mechanical properties of the plant cell wall through the degradation of pectins, one of its major constituents. PGs are largely used in food, beverage, textile, and paper industries to increase processes' performances. To improve the use of PGs, knowledge of their biochemical, structural and functional features is of prime importance. Our study aims at characterizing SmoPG1, a polygalacturonase from Selaginella moellendorffii, that belongs to the lycophytes. Transcription data showed that SmoPG1 was mainly expressed in S. moellendorffii shoots while phylogenetic analyses suggested that SmoPG1 is an exo-PG, which was confirmed by the biochemical characterization following its expression in heterologous system. Indeed, LC-MS/MS oligoprofiling using various pectic substrates identified galacturonic acid (GalA) as the main hydrolysis product. We found that SmoPG1 was most active on polygalacturonic acid (PGA) at pH 5, and that its activity could be modulated by different cations (Ca2+, Cu2+, Fe2+, Mg2+, Mn2+, Na2+, Zn2+). In addition, SmoPG1 was inhibited by green tea catechins, including (-)-epigallocatechin-3-gallate (EGCG). Docking analyses and MD simulations showed in detail amino acids responsible for the SmoPG1-EGCG interaction. Considering its expression yield and activity, SmoPG1 appears as a prime candidate for the industrial production of GalA.


Pectins , Polygalacturonase , Selaginellaceae , Polygalacturonase/metabolism , Polygalacturonase/chemistry , Polygalacturonase/genetics , Selaginellaceae/chemistry , Selaginellaceae/genetics , Selaginellaceae/enzymology , Pectins/metabolism , Pectins/chemistry , Phylogeny , Substrate Specificity , Molecular Docking Simulation , Amino Acid Sequence , Hydrogen-Ion Concentration , Hydrolysis , Hexuronic Acids
12.
Int J Biol Macromol ; 267(Pt 1): 131278, 2024 May.
Article En | MEDLINE | ID: mdl-38582459

Four modified hawthorn pectin fractions (MHPs), named MHP-30, MHP-50, MHP-70 and MHP-90, were obtained by ultrasonic-assisted pectin methyl esterase modification and gradient ethanol precipitation. The results indicated that all four MHPs were composed of galacturonic acid, galactose, xylose, arabinose, glucose and mannose in different proportions. With the increase of the ethanol concentration, the molecular weight, esterification degree and galacturonic acid content of MHPs all decreased, whereas the arabinose content and branching degree increased. The structural characterization from XRD, SEM, and FT-IR showed that four MHPs exhibited amorphous structure, similar functional groups, diverse surface morphologies. Besides, in vitro antioxidant assays confirmed that MHP-70 and MHP-90 exhibited stronger total antioxidant activities than MHP-30 and MHP-50. The results of simulated saliva-gastrointestinal digestion showed that the molecular weight of MHP-70 and MHP-90 remained stable, yielded small amounts of reducing sugars, and were resistant to digestion in the human upper digestive tract. Overall, MHP-70 and MHP-90 shown great potential as novel natural antioxidants, which are expected to be good carbon sources for the utilization of intestinal microorganisms.


Antioxidants , Crataegus , Ethanol , Pectins , Pectins/chemistry , Pectins/metabolism , Antioxidants/chemistry , Antioxidants/pharmacology , Ethanol/chemistry , Crataegus/chemistry , Digestion , Molecular Weight , Humans , Chemical Precipitation , Spectroscopy, Fourier Transform Infrared
13.
J Biotechnol ; 388: 35-48, 2024 Jun 10.
Article En | MEDLINE | ID: mdl-38641136

Whey protein isolate (WPI) was incorporated within calcium pectinate (CPT) beads in order to boost their anionic qualities and meliorate their glutaraldehyde (GA)-polyethyleneimine (PEI) grafting process. The Box-Behnken Design (BBD) verified that WPI inclusion significantly raised the GA-PEI-CPT-WPI beads immobilized ß-D-galactosidase (iß-GLD) activity. The BBD also revealed the optimal settings for WPI concentration, PEI pH, PEI concentration, and GA concentration, which were 2.91 %, 10.8, 3.5 %, and 2.24 %, respectively. The GA-PEI-CPT-WPI beads grafting process was scrutinized via FTIR, EDX, and SEM. The optimal GA-PEI-CPT-WPI immobilizers provided fine ß-GLD immobilization efficiencies, which reached up to 65.28 %. The free and GA-PEI-CPT-WPI iß-GLDs pH and temperature profiles were scrutinized. It was also unveiled that the thermal stability of the iß-GLD surpassed that of its free compeer as it provided lesser kd and ΔS values and larger t1/2, D-values, Ed, ΔH, and ΔG values. Furthermore, the iß-GLD provided 92.00±3.39 % activity after 42 storage days, which denoted its fine storage stability. The iß-GLD short duration (15 min) operational stability was also inspected, and 82.70±0.78 % activity was provided during the fifteenth degradation run. Moreover, the iß-GLD long duration (24 h) operational stability was inspected while degrading the lactose of buffered lactose solution (BLS) and cheese whey (CW). It was unveiled that 81.86±0.96 % and 73.58±2.24 % of the initial glucose were detected during the sixth degradation runs, respectively.


Enzymes, Immobilized , Polyethyleneimine , Thermodynamics , Whey Proteins , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/metabolism , Whey Proteins/chemistry , Kinetics , Polyethyleneimine/chemistry , Hydrogen-Ion Concentration , Pectins/chemistry , Pectins/metabolism , beta-Galactosidase/metabolism , beta-Galactosidase/chemistry , Glutaral/chemistry , Temperature , Enzyme Stability
14.
Proc Natl Acad Sci U S A ; 121(15): e2321759121, 2024 Apr 09.
Article En | MEDLINE | ID: mdl-38579009

Adjacent plant cells are connected by specialized cell wall regions, called middle lamellae, which influence critical agricultural characteristics, including fruit ripening and organ abscission. Middle lamellae are enriched in pectin polysaccharides, specifically homogalacturonan (HG). Here, we identify a plant-specific Arabidopsis DUF1068 protein, called NKS1/ELMO4, that is required for middle lamellae integrity and cell adhesion. NKS1 localizes to the Golgi apparatus and loss of NKS1 results in changes to Golgi structure and function. The nks1 mutants also display HG deficient phenotypes, including reduced seedling growth, changes to cell wall composition, and tissue integrity defects. These phenotypes are comparable to qua1 and qua2 mutants, which are defective in HG biosynthesis. Notably, genetic interactions indicate that NKS1 and the QUAs work in a common pathway. Protein interaction analyses and modeling corroborate that they work together in a stable protein complex with other pectin-related proteins. We propose that NKS1 is an integral part of a large pectin synthesis protein complex and that proper function of this complex is important to support Golgi structure and function.


Arabidopsis Proteins , Arabidopsis , Arabidopsis/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Cell Adhesion/genetics , Pectins/metabolism , Golgi Apparatus/genetics , Golgi Apparatus/metabolism , Cell Wall/metabolism
15.
Physiol Plant ; 176(3): e14320, 2024.
Article En | MEDLINE | ID: mdl-38686642

Many nucleoside triphosphate-diphosphohydrolases (NTPDases/APYRASEs, APYs) play a key role in modulating extracellular nucleotide levels. However, the Golgi-localized APYs, which help control glycosylation, have rarely been studied. Here, we identified AtAPY1, a gene encoding an NTPDase in the Golgi apparatus, which is required for cell wall integrity and plant growth under boron (B) limited availability. Loss of function in AtAPY1 hindered cell elongation and division in root tips while increasing the number of cortical cell layers, leading to swelling of the root tip and abundant root hairs under low B stress. Further, expression pattern analysis revealed that B deficiency significantly induced AtAPY1, especially in the root meristem and stele. Fluorescent-labeled AtAPY1-GFP localized to the Golgi stack. Biochemical analysis showed that AtAPY1 exhibited a preference of UDP and GDP hydrolysis activities. Consequently, the loss of function in AtAPY1 might disturb the homoeostasis of NMP-driven NDP-sugar transport, which was closely related to the synthesis of cell wall polysaccharides. Further, cell wall-composition analysis showed that pectin content increased and borate-dimerized RG-II decreased in apy1 mutants, along with a decrease in cellulose content. Eventually, altered polysaccharide characteristics presumably cause growth defects in apy1 mutants under B deficiency. Altogether, these data strongly support a novel role for AtAPY1 in mediating responses to low B availability by regulating cell wall integrity.


Apyrase , Arabidopsis Proteins , Arabidopsis , Boron , Cell Wall , Golgi Apparatus , Arabidopsis/genetics , Arabidopsis/growth & development , Arabidopsis/enzymology , Arabidopsis/metabolism , Cell Wall/metabolism , Boron/metabolism , Boron/deficiency , Golgi Apparatus/metabolism , Arabidopsis Proteins/metabolism , Arabidopsis Proteins/genetics , Apyrase/metabolism , Apyrase/genetics , Gene Expression Regulation, Plant , Plant Roots/growth & development , Plant Roots/genetics , Plant Roots/metabolism , Meristem/genetics , Meristem/growth & development , Meristem/metabolism , Pectins/metabolism
16.
Carbohydr Polym ; 336: 122122, 2024 Jul 15.
Article En | MEDLINE | ID: mdl-38670769

Pectin interacts with fibronectin (FN), a modular protein in the extracellular matrix. This interaction is significant as FN plays a pivotal role by binding to the receptor integrin α5ß1. However, the molecular mechanism underlying the pectin-FN interaction and its impact on integrin binding remains unknown. In this study, water-soluble pectins (WSPs) were extracted from three different pectin sources and subsequently characterized. These included Citrus WSP, which primarily comprises the homogalacturonan region, and Kaki and Yuzu WSPs, both of which are rich in rhamnogalacturonan regions. We investigated the molecular interactions between these WSPs and two FN fragments, Anastellin and RetroNectin, using surface plasmon resonance analysis. Citrus WSP exhibited a notable binding affinity to FN, with a dissociation constant (KD) of approximately 10-7 M. In contrast, Kaki and Yuzu WSPs displayed comparatively weaker or negligible binding affinities. The binding reactivity of Citrus WSP with FN was notably diminished following the enzymatic removal of its methyl-ester groups. Additionally, Citrus WSP disrupted the binding of integrin ß1 to RetroNectin without altering the affinity, despite its minimal direct binding to integrin itself. This study furthers our understanding of the intricate pectin-FN interaction and sheds light on their potential physiological relevance and impact on cellular responses.


Fibronectins , Integrin beta1 , Pectins , Protein Binding , Pectins/metabolism , Pectins/chemistry , Fibronectins/metabolism , Fibronectins/chemistry , Integrin beta1/metabolism , Citrus/chemistry , Citrus/metabolism , Humans , Surface Plasmon Resonance
17.
Int J Biol Macromol ; 267(Pt 2): 131565, 2024 May.
Article En | MEDLINE | ID: mdl-38614184

Endopolygalacturonases are crucial pectinases known for their efficient and sustainable pectin depolymerization activities. The present study identified a novel gene encoding endopolygalacturonase from an acidic mine tailing metagenome. The putative gene showed a maximum identity of 67.55 % with an uncharacterized peptide sequence from Flavobacterium fluvii. The gene was cloned and expressed in a heterologous host, E. coli. Biochemical characterization of the novel endopolygalacturonase enzyme variant (EPHM) showed maximum activity at 60 °C and at 5.0 pH, while retaining 50 % activity under the temperature and pH range of 20 °C to 70 °C for 6 h, and 3.0 to 10.0 for 3 h, respectively. The enzyme exhibited tolerance to different metal ions. EPHM was characterized for the depolymerization of methylated pectin into pectic oligosaccharides. Further, its utility was established for fruit juice clarification, as endorsed by high transmittance, significant viscosity reduction, and release of reducing sugars in the treated fruit juice samples.


Fruit and Vegetable Juices , Pectins , Polygalacturonase , Pectins/metabolism , Pectins/chemistry , Polygalacturonase/metabolism , Polygalacturonase/chemistry , Polygalacturonase/genetics , Fruit and Vegetable Juices/analysis , Hydrogen-Ion Concentration , Temperature , Cloning, Molecular , Polymerization , Oligosaccharides/chemistry
18.
Int J Biol Macromol ; 266(Pt 2): 131309, 2024 May.
Article En | MEDLINE | ID: mdl-38580019

Enzymatic degradation of plant biomass requires the coordinated action of various enzymes. In this study, the production of reducing sugars from pectic substrates and sugar beet pulp (SBP) was investigated and compared using commercial enzyme preparations, including M2, pectinase (E1), Viscozyme L (V-L) and L-40. V-L, a cellulolytic enzyme mix produced by Aspergillus sp. was further evaluated as the most robust enzyme cocktail with the strongest SBP degradation ability in terms of the release of monosaccharides, methanol, and acetate from SBP. Mass-spectrometry-based proteomics analysis of V-L revealed 156 individual proteins. Of these, 101 proteins were annotated as containing a carbohydrate-active enzyme module. Notably, of the 50 most abundant proteins, ca. 44 % were predicted to be involved in pectin degradation. To reveal the role of individual putative key enzymes in pectic substrate decomposition, two abundant galacturonases (PglA and PglB), were heterologously expressed in Pichia pastoris and further characterized. PglA and PglB demonstrated maximum activity at 57 °C and 68 °C, respectively, and exhibited endo-type cleavage patterns towards polygalacturonic acid. Further studies along this line may lead to a better understanding of efficient SBP degradation and may help to design improved artificial enzyme mixtures with lower complexity for future application in biotechnology.


Pectins , Proteomics , Pectins/metabolism , Proteomics/methods , Substrate Specificity , Polygalacturonase/metabolism , Polygalacturonase/chemistry , Beta vulgaris/chemistry , Beta vulgaris/metabolism , Aspergillus/enzymology
19.
Plant Physiol Biochem ; 210: 108621, 2024 May.
Article En | MEDLINE | ID: mdl-38604012

To enhance the postharvest quality of avocado (Persea americana Mill.) fruit, this study investigates alterations in cell wall metabolism and reactive oxygen species (ROS) metabolism during near-freezing temperature (NFT) storage, and explores their impact on fruit softening. The fruit was stored at 25 °C, 5 °C, 2 °C, and NFT, respectively. NFT storage retarded firmness loss and chilling injury in comparison with 25 °C, 5 °C, and 2 °C. NFT storage delayed the decrease of ionic-soluble pectin (ISP) and cellulose (CLL) contents by suppressing cell wall degradation enzyme activities. Correlation analysis showed that cell wall degradation enzyme activities were positively correlated to rates of ethylene release and respiration. Moreover, NFT storage maintained higher levels of DPPH and ABTS scavenging abilities, activities of superoxide dismutase, peroxidase, and catalase, as well as ascorbate-glutathione cycle (ascorbic acid, glutathione, glutathione disulfide, ascorbate peroxidase, cycle-related enzymes), thereby inhibited the increase of ROS content, malondialdehyde content, and cell membrane permeability. Fruit firmness and chilling injury were correlated with the contents of hydrogen (H2O2), superoxide anion (O2.-), ISP, and CLL. These results suggested that NFT could suppress fruit softening and chilling injury by inhibiting cell wall degradation through delaying respiration and ethylene production and suppressing ROS production via activation of antioxidant systems, thereby maintaining quality and prolonged storage life during avocado fruit storage.


Cell Wall , Fruit , Persea , Reactive Oxygen Species , Persea/metabolism , Cell Wall/metabolism , Reactive Oxygen Species/metabolism , Fruit/metabolism , Food Storage/methods , Cold Temperature , Freezing , Ethylenes/metabolism , Pectins/metabolism , Cellulose/metabolism
20.
BMC Plant Biol ; 24(1): 295, 2024 Apr 17.
Article En | MEDLINE | ID: mdl-38632520

The extraction of bast fibres such as jute from plant stems involves the removal of pectin, hemicellulose, and other noncellulosic materials through a complex microbial community. A consortium of pectinolytic bacterial strains has been developed and commercialized to reduce the retting time and enhance fibre quality. However, there are currently no studies on jute that describe the structural changes and sequential microbial colonization and pectin loss that occur during microbe-assisted water retting. This study investigated the stages of microbial colonization, microbial interactions, and sequential degradation of pectic substances from jute bark under controlled and conventional water retting. The primary occurrence during water retting of bast fibres is the bacterially induced sequential breakdown of pectin surrounding the fibre bundles. The study also revealed that the pectin content of the jute stem significantly decreases during the retting process. These findings provide a strong foundation for improving microbial strains for improved pectinolysis with immense industrial significance, leading to a sustainable jute-based "green" economy.


Corchorus , Corchorus/metabolism , Water/metabolism , Pectins/metabolism , Bacteria/metabolism
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