Search Results (181)

Segregative phase separation technology demonstrates substantial potential for precise molecular fractionation in food and biomaterial applications. The investigation elucidates the causal relationship between viscosity variations and phase separation dynamics, which govern molecular fractionation in GA/HPMC composite systems. By conducting a comparative analysis of two GA subtypes (CGA and SGA) and three HPMC grades with controlled viscosity gradients, we utilized gel permeation chromatography-multi-angle laser light scattering (GPC-MALLS) coupled with rheological characterization to elucidate the critical relationship between continuous phase viscosity and fractionation efficiency. Notably, increasing HPMC viscosity significantly intensified phase separation, resulting in selective enrichment of arabinogalactan-protein complexes: from 6.3% to 8.5% in CGA/HPMC systems and from 27.3% to 36.5% in SGA/HPMC systems. Further mechanistic investigation revealed that elevated HPMC viscosity enhances thermodynamic incompatibility while slowing interfacial mass transfer, synergistically driving component redistribution. These findings establish a quantitative viscosity–fractionation relationship, offering theoretical insights for optimizing GA/HPMC systems in emulsion stabilization, microencapsulation, and functional biopolymer purification via viscosity-mediated phase engineering. Full article

Background: Aluminum (Al) toxicity severely limits Medicago sativa (alfalfa) production on acidic soils, resulting in major yield losses worldwide. The highly conserved miRNA156 (miR156) functions by downregulating at least 11 SQUAMOSA promoter-binding protein-like (SPL) transcription factors in alfalfa, including SPL13, but its role in Al stress remains unclear. This study aimed to investigate the miR156/SPL regulatory network’s function in alfalfa under Al stress. Methods: Gene expression analyses, histochemical staining, nutrient profiling, phenotypic assays, transcriptome profiling, and ChIP-seq were conducted on alfalfa plants with altered miR156 and SPL13 expression to assess their roles in the Al stress response. Results: Al stress induced SPL13 expression while repressing miR156 in the roots. Elevated miR156 intensified Al accumulation, lipid peroxidation, and plasma membrane damage, accompanied by reduced leaf nitrogen, magnesium, sulfur, and phosphorus content. Phenotypically, increased SPL13 enhanced the root length and Al tolerance, whereas SPL13 silencing reduced tolerance. Transcriptome profiling of SPL13-silenced plants identified differentially expressed genes involved in the Al response, including aluminum-activated malate transporters and various transcription factors (GRAS, Myb-related, bHLH041, NAC, WRKY53, bZIP, and MADS-box). ChIP-seq revealed that SPL13 directly regulates genes encoding a protein kinase, cytochrome P450, and fasciclin-like arabinogalactan proteins. Conclusions: The MsmiR156/MsSPL13 network plays a crucial regulatory role in alfalfa’s response to Al toxicity. These findings provide novel genetic targets and foundational knowledge to advance molecular breeding for enhanced Al tolerance in alfalfa. Full article

Wild fruits are distributed worldwide, but are consumed mainly in developing countries, where they are an important part of the diet. Still, in many other countries, they are consumed only locally. Blackthorn (Prunus spinosa L.) is an underutilized species rich in fibres and phenolic compounds, making it suitable as a potential functional food for supporting human health. Cold (Cw) and hot (Hw) water-extracted (poly)phenolic polysaccharide–protein complexes, differing in carbohydrate, phenolic and protein contents, were isolated from blackthorn fruits and characterized. The complexes exhibited molecular weights of 235,200 g/mol (Cw) and 218,400 g/mol (Hw), and were rich in pectic polymers containing galacturonic acid, arabinose, galactose and rhamnose, indicating a dominance of homogalacturonan (HG) [→4)-α-D-GalA(1→4)-α-D-GalA(1→]n and a low content of RGI [→2)-α-L-Rha(1→4)-α-D-GalA(1→2)-α-L-Rha(1→]n sequences associated with arabinan or arabinogalactan. Minor content of glucan, probably starch-derived, was also solubilized. Pectic polysaccharides were highly esterified and partly acetylated. Pharmacological testing was performed in male Dunkin–Hartley guinea pigs, a model with human-like airway reflexes. Both complexes affected airway defense mechanisms. Particularly, Hw significantly suppressed citric acid-induced cough, similar to codeine, and reduced bronchoconstriction comparably to salbutamol in a dose-dependent manner. These findings support further exploration of Hw as a natural antitussive and bronchodilatory agent. Full article

Arabinogalactan proteins (AGPs) constitute a diverse class of hydroxyproline-rich glycoproteins implicated in various aspects of plant growth and development. However, their functional characterization in cotton (Gossypium spp.) remains limited. As a globally significant economic crop, cotton serves as the primary source of natural fiber, making it essential to understand the genetic mechanisms underlying its growth and development. This study aims to perform a comprehensive genome-wide identification and characterization of the AGP gene family in Gossypium spp., with a particular focus on elucidating their structural features, evolutionary relationships, and functional roles. A genome-wide analysis was conducted to identify AGP genes in Gossypium spp., followed by classification into distinct subfamilies based on sequence characteristics. Protein motif composition, gene structure, and phylogenetic relationships were examined to infer potential functional diversification. Subcellular localization of a key candidate gene, GhAGP50, was determined using fluorescent protein tagging, while gene expression patterns were assessed through β-glucuronidase (GUS) reporter assays. Additionally, hormonal regulation of GhAGP50 was investigated via treatments with methyl jasmonate (MeJA), abscisic acid (ABA), indole-3-acetic acid (IAA), and gibberellin (GA). A total of 220 AGP genes were identified in Gossypium spp., comprising 19 classical AGPs, 28 lysine-rich AGPs, 55 AG peptides, and 118 fasciclin-like AGPs (FLAs). Structural and functional analyses revealed significant variation in gene organization and conserved motifs across subfamilies. Functional characterization of GhAGP50, an ortholog of AGP18 in Arabidopsis thaliana, demonstrated its role in promoting epidermal hair formation in leaves and stalks. Subcellular localization studies indicated that GhAGP50 is targeted to the nucleus and plasma membrane. GUS staining assays revealed broad expression across multiple tissues, including leaves, inflorescences, roots, and stems. Furthermore, hormonal treatment experiments showed that GhAGP50 expression is modulated by MeJA, ABA, IAA, and GA, suggesting its involvement in hormone-mediated developmental processes. This study presents a comprehensive genome-wide analysis of the AGP gene family in cotton, providing new insights into their structural diversity and functional significance. The identification and characterization of GhAGP50 highlight its potential role in epidermal hair formation and hormonal regulation, contributing to a deeper understanding of AGP functions in cotton development. These findings offer a valuable genetic resource for future research aimed at improving cotton growth and fiber quality through targeted genetic manipulation. Full article

It has been previously shown that a selenium (Se) nanocomposite (NC) based on the natural polysaccharide arabinogalactan (AG) produced from Siberian larch wood (Larix sibirica Ledeb.), containing 0.000625% of Se, has antibacterial properties against phytopathogens, such as Clavibacter sepedonicus, Pectobacterium carotovorum, and Phytophthora cactorum. The same concentration of Se/AG NC stimulated the growth and development of potato plants in vitro, as well as the formation of their roots, while Se did not accumulate in potato tissues after plant treatment. However, to realize the full potential of Se/AG NC in agriculture for fighting phytopathogens with the aim of developing commercial nanopreparations, additional toxicological studies are needed to fully address their effects. In this study, to assess the environmental risk of using Se/AG NCs, it was applied to a number of bacteria isolated from soil (Escherichia coli, Bacillus cereus, and B. megaterium), water (Micrococcus luteus, B. subtilis, and Sarcina flava), and activated sludge and wastewater of treatment facilities (Serratia marcescens, M. luteus, B. cereus, and Pseudomonas aeruginosa). When studying the antibacterial activity of Se/AG NC against 11 test cultures of bacteria using the agar diffusion method, it was shown that Se/AG NC had a toxic effect only at high concentrations in the range from 40 mg/mL Se/AG NC (1.68 mg/mL Se) to 0.625 mg/mL Se/AG NC (0.026 mg/mL Se) on two types of bacteria M. luteus isolated from the waters of Lake Baikal and B. cereus obtained from activated sludge of treatment facilities. The maximum diameter of the growth inhibition zone of the test cultures after exposure to different concentrations of Se/AG NC was noted for M. luteus (water) and E. coli (soil) at 40 mg/mL − 26.3 and 20.3 mm, respectively. Thus, the negative impact of Se/AG NC on bacteria from different ecological niches was registered only at high concentrations, similar to the predicted concentrations of Se/AG NC in wastewater, which demonstrates the environmental safety of Se/AG NC for use in agriculture. Full article

Epiphytic lichens are integral to boreal forest ecosystems, yet their allelopathic interactions with host trees, particularly in cryolithozone regions, remain poorly understood. This study elucidates the physiological and biochemical impacts of the epiphytic lichen Physcia alnophila on Larix gmelinii (Gmelin larch), a keystone species in Siberian permafrost forests. By combining dendrochronology, GC–MS metabolomic analysis, and HPLC–ESI–MS/MS analysis, we demonstrate that the lichen’s primary metabolite, atranorin (ATR), systemically migrates from thalli into the host’s cambium, roots, and needles, with root accumulation reaching 36.3 µg g⁻¹ DW. Lichen-colonized trees exhibited severe radial growth inhibition (27%–51% reduction over five years) and suppressed apical growth, despite comparable heights to controls, indicating chronic phytotoxicity. Metabolomic profiling revealed lichen-specific polyols (e.g., arabitol, mannitol) in larch tissues, alongside elevated stress biomarkers (terpenes, sterols, phenolic acids), and significant disruptions to the tricarboxylic acid cycle and oxidative phosphorylation. These metabolic perturbations correlate with reduced monosaccharide availability and impaired energy production, directly linking ATR translocation to growth suppression. L. gmelinii exhibited compensatory responses, including increased fatty acids and arabinogalactan synthesis, suggesting adaptive mechanisms to mitigate lichen-induced stress. Our findings suggest P. alnophila as a biotic stressor that affects tree physiology in extreme climates, with implications for boreal forest resilience. This work provides an insight to the rarely pointed out species interactions, which, when combined with climate change, may alter carbon cycling and forest dynamics in permafrost ecosystems. Full article

Bryophytes, or non-vascular plants, provide valuable models for studying plant adaptation to land, as their physiology differs significantly from that of vascular plants. This study examines the cell wall structure of bryophytes, focusing on the tissue-specific distribution of cell wall epitopes in Sphagnum compactum (a peat moss) and Marchantia polymorpha (the model liverwort) using specific stains and immunolabeling techniques. In S. compactum, chlorocysts and hyalocysts exhibit distinct polysaccharide compositions, with methylesterified and demethylesterified homogalacturonans, arabinans, and hemicelluloses contributing to water retention, structural integrity, and photosynthetic efficiency. In contrast, M. polymorpha demonstrates a simpler yet polarized distribution of homogalacturonans, arabinans, mannans, and xyloglucans, with arabinogalactan proteins uniquely localized in rhizoids, improving their flexibility and anchorage to the substrate. Cellulose was uniformly distributed throughout all tissues in both bryophytes, while crystalline cellulose was only faintly observed. These findings highlight how cell wall adaptations contribute to ecological specialization, providing insights into the evolutionary innovations that enable bryophytes to thrive in terrestrial environments. Full article

Background: Inflammatory bowel diseases, such as ulcerative colitis and Crohn’s disease, affect the gastrointestinal tract. Treatment aims to induce remission and relieve symptoms but may fail or cause side effects. Recent studies suggest that natural polysaccharides can reduce inflammation and promote healing. The polysaccharides of the pulp of tamarillo (Solanum betaceum cav.) have shown beneficial effects, but their potential in colitis is still unexplored. Objective: To investigate the effect of polysaccharides from tamarillo pulp in an animal model of ulcerative colitis. Methods: Polysaccharides from tamarillo pulp (STWA) were extracted and tested in female mice (BALB/c) to investigate their effect on dextran sodium sulfate (DSS)-induced ulcerative colitis. Different doses of the polysaccharides were tested (10 mg/kg, 30 mg/kg, and 100 mg/kg). The course of the disease and the weight of the animals were monitored daily. At the end of the experimental protocol, the large intestine was removed and measured. Markers of oxidative stress and inflammation were then analyzed. Histological analysis was performed to assess microscopic changes. Results: Treatment with STWA (100 mg/kg) prevented weight loss in mice with DSS-induced colitis and reduced the disease activity index. The colon length was preserved, and occult blood in the feces was reduced. Treatment with STWA controlled oxidative stress. Glutathione S-transferase (GST) levels increased, while lipid peroxidation decreased. The inflammatory process was reduced, as indicated by the decrease in myeloperoxidase (MPO), N-acetylglucosamine (NAG), and tumor necrosis factor alpha (TNF-α) levels and the increase in interleukin 10 (IL-10) levels. STWA also improved the colon histology, while preserving the colonic epithelium. Conclusions: The results suggest that STWA has protective potential and reduces inflammation in an experimental model of ulcerative colitis in mice. Full article

Honey has been used for centuries for its antibacterial and healing properties. The aim of this study was to investigate the antibacterial properties, arabinogalactan proteins (AGPs), antioxidant activities, and polyphenolic content of eight different types of New Zealand honey (clover, mānuka, beech honeydew, pōhutukawa, kānuka, rewarewa, kāmahi and thyme honey). The results showed varying antibacterial activities across the honey types, with mānuka, pōhutukawa, and kāmahi honey exhibiting significant inhibitory effects. Interestingly, all honey samples demonstrated inhibitory effects on bacterial growth at 25% concentration. Furthermore, AGPs were found in all eight honey samples, with higher amounts in kānuka, kāmahi, pōhutukawa, mānuka, and rewarewa honey. Thyme had the highest antioxidant values in terms of CUPRAC, FRAP and DPPH, while kāmahi honey had the lowest antioxidant value. Beech honeydew honey had the highest Total Flavonoid Content (TFC) values, while thyme and clover honey had the lowest TFC values. Similarly, thyme honey exhibited the highest Total Phenolic Content (TPC) value, with kāmahi and clover honey having the lowest TPC values. Furthermore, only thyme and beech honeydew New Zealand honeys contained vitamin C. The different honeys contained varying concentrations of polyphenols, with mānuka, kānuka, and pōhutukawa honeys having high amounts of quercetin, luteolin, and gallic acid, respectively. In contrast, clover honey had notable levels of chrysin, pinocembrin, caffeic acid, and pinobanksin. Overall, this study provides valuable insights into the antibacterial properties and bioactivities of native New Zealand honeys, contributing to our understanding of the potential health benefits associated with these honeys and their potential use as natural alternatives to improve human health. Full article

The effect of a surface coating with an aqueous solution containing a synthetic diammonium hydrogen phosphate fire retardant and vacuum pressure impregnation with a synthetic diammonium hydrogen phosphate fire retardant, potassium acetate, and a natural polymeric retardant, arabinogalactan, to improve the fire resistance and selected properties of structural fir (Abies alba L.) wood was investigated in this article. The combustion characteristics were investigated, and the heat of combustion reflects the effect of the presence of fire retardants. Changes in the content of cellulose, hemicelluloses, holocellulose, lignin, and extractives characterize the chemical changes in wood caused by these factors. The relationship between the combustion characteristics and chemical changes in chemically modified wood as a consequence of the presence of flame retardants were assessed using Fourier transform infrared spectroscopy. The results showed that the effectiveness of the fire retardants against ignition and burning when applied by vacuum pressure impregnation was always higher than in the case of surface coating, even when using impregnation solutions of low concentrations. In the case of diammonium hydrogen phosphate, a low 5% concentration of retardant was sufficient to provide suitable flame retardancy. Further, degradation by depolymerization of cellulose occurred only at temperatures between 460 and 470 °C. Low concentrations of retardant limit the loss to the environment and consequent ecological impact. Full article

Arabinoxylan, a key non-starch polysaccharide in wheat bran, significantly influences the quality and health benefits of wheat beer. This study aimed to investigate how wheat bran addition (0–20%) affects water-extracted arabinoxylan (WEAX) content and beer quality in 100% wheat malt beer. The study integrated physicochemical analyses (polysaccharide composition, WEAX molecular weight), process parameters (wort filtration time, foam stability), and sensory evaluation to establish structure–function relationships. Results showed that the WEAX content in beer increased from 1.36 mg/mL in pure malt beer (0% bran) to 2.25 mg/mL with 20% bran addition. Bran addition shortened wort filtration time by 20–45%. The molecular weight of WEAX was mainly 2936–7062 Da, enhancing foam expansion (36.18%) and stability (15.54%) due to elevated polymerization and arabinose-to-xylose (A/X) ratios. WEAX fractions (7062–10,134 Da and 859–2936 Da) correlated positively with beer turbidity and viscosity. Sensory analysis identified 15% bran as optimal for balanced quality. These findings demonstrate that bran addition enhances WEAX content, polymerization, and A/X ratios, improving foam performance, reducing filtration time, and optimizing beer quality without altering arabinogalactan, glucan, or mannose polymer content. Full article

Arabinogalactan proteins (AGPs) are complex proteoglycans present in plant cell walls across the kingdom. They play crucial roles in biological functions throughout the plant life cycle. In this study, we identified 43 gene members of the AG peptide (an AGP subfamily) within the rice genome, detailing their structure, protein-conserved domains, and motif compositions for the first time. We also examined the expression patterns of these genes across 18 tissues and organs, especially the different parts of the flower (anthers, pollen, pistil, sperm cells, and egg cells). Interestingly, the expression of some AG peptides is mainly present in the pollen grain. Transcription data and GUS staining confirmed that OsAGP6P—a member of the AG peptide gene family—is expressed in the stamen during pollen development stages 11–14, which are critical for maturation as microspores form after meiosis of pollen mother cells. It became noticeable from stage 11, when exine formation occurred—specifically at stage 12, when the intine began to develop. The overexpression of this gene in rice decreased the seed-setting rate (from 91.5% to 30.5%) and plant height (by 21.9%) but increased the tillering number (by 34.1%). These results indicate that AGP6P contributes to the development and fertility of pollen, making it a valuable gene target for future genetic manipulation of plant sterility through gene overexpression or editing. Full article

Sulfation of arabinogalactan (AG) from larch wood (Larix sibirica Ledeb.) in the melt of a sulfamic acid–urea mixture has been first examined. The impact of the AG sulfation temperature on the AG sulfate yield and the sulfur content has been established. The high sulfur content (11.3–11.6%) in sulfated AG has been obtained in the temperature range of 115–120 °C for a sulfation time of 0.5 h. The process effectively prevents molecular degradation under these conditions. The incorporation of sulfate groups into the arabinogalactan structure has been confirmed by the appearance of absorption bands in the FTIR spectrum that are typical of sulfate group vibrations. The ¹³C NMR spectroscopy study has proven that the AG sulfation in the melt of a sulfamic acid–urea mixture leads to the substitution of some free hydroxyl groups for C6, C4, and C2 carbon atoms of the AG β-D-galactopyranose units. The advantage of the proposed AG sulfation method is that the reaction occurs without solvent, and the reaction time is only 0.5 h. The kinetics of the thermal decomposition of the initial AG and sulfated AG samples have been studied. It has been found that the sulfated AG samples have a lower thermal resistance than the initial AG. The kinetic analysis has revealed a decrease in the activation energy of the thermal degradation of the sulfated samples as compared to the initial AG. Full article

Different dietary fibers have distinct structures, leading to significant variations in their laxative effects. To explore how these structural differences impact constipation intervention, a 14-day study was conducted on loperamide-induced constipated mice using five dietary fibers: soluble dietary fiber from steamed sweet potato (SDF-S), oat β-glucan (OB), polydextrose (PD), arabinogalactan (AG), and inulin (IN). The results showed that four fibers, excluding PD, significantly improved gastrointestinal (GI) transit rate (p < 0.05), although PD had the highest fecal moisture, it was significantly different from the lowest IN (p < 0.05). AG and IN resulted in higher 6 h fecal weights compared to other fibers. SDF-S and OB were more effective in modulating serum levels of gastrointestinal hormones. The different monosaccharide compositions and glycosidic bonds of these fibers led to distinct changes in gut microbiota composition and SCFA profiles. Galactose and arabinose in AG were linked to increased abundance of Lachnospiraceae_UCG-006, Bacteroides, and Odoribacter, promoting butyrate fermentation, which is positively correlated with GI transit rate. Glucose in SDF-S, OB, and PD favored acetate fermentation positively correlated with fecal moisture. Fructose in IN encouraged the proliferation of Muribaculaceae_unclassified and Ruminococcus, associated with butyrate fermentation and increased 6 h stool weight, respectively. The β-glycosidic bonds in OB may lead to high butyrate production through the selective proliferation of Lachnospiraceae_unclassified. Minor components like fucose, rhamnose, and ribose were positively correlated with the abundance of Oscillospiraceae_unclassified, Anaerotignum, and Lachnospiraceae_unclassified. In conclusion, the unique monosaccharide compositions and glycosidic bond differences in dietary fibers selectively promote the proliferation of fiber-degrading and butyrate-producing bacteria, resulting in varied effects on constipation relief. Full article

Carnivorous plants have fascinated botanists and ecologists with their various unusual adaptations in organ structure, physiology, and complex interactions with other organisms since the time of Charles Darwin. Species of the genus Utricularia (bladderworts, family Lentibulariaceae) are carnivorous plants that prey mainly on invertebrates using traps (bladders) of leaf origin. In the traps, there are glandular trichomes called quadrifids, which produce digestive enzymes and absorb the products of prey digestion. These quadrifids are unique due to their highly complex glandular cell structure; hence, they are an excellent model for studying the cell wall and its specialization. The main aim of the study was to investigate the presence and distribution of homogalacturonans (HGs) and hemicelluloses in the cell walls of trichome cells and especially in cell wall ingrowths in the quadrifid cells. The following antibodies were used against the wall components: anti-HGs (homogalacturonans) —JIM5 (low methylesterified HGs), JIM7 (highly esterified HGs), LM19 (low methylesterified HGs), CCRC-M38 (a fully de-esterified HG), LM5 (galactan); anti-hemicelluloses—LM25 (galactoxyloglucan; XXLLG, XXLG, XXXG modules of xyloglucans), LM15 (xyloglucan), CCRC-M138 (xylan), LM11 (heteroxylan); and anti-mannans: LM20 (heteromannan) and LM22 (heteromannan). The localization of the examined compounds was determined using immunohistochemistry techniques and immunogold labeling. In quadrifid cells, we found differences in the presence of the epitope detected by the LM5 antibody in the cell walls. In addition, cell wall ingrowths represented distinct microdomains of the cell wall in terms of the occurrence of wall components (they were methylesterified and demethylesterified homogalacturonan-poor). Hemicelluloses (galactoxyloglucan and xyloglucan) and arabinogalactans co-occur in cell wall ingrowths. Also, a part of the cell wall of the pedestal cell, which forms a Casparian strip, represented a distinct microdomain. We did not detect epitopes recognized by LM11, LM20 and LM22 antibodies. Our research shows that several cell wall microdomains occur in the cell walls of quadrifid cells. They differ depending on the presence and distribution of low methylesterified HGs, highly esterified HGs, fully de-esterified HGs, galactan (the epitope detected by the LM5 antibody), xyloglucan, galactoxyloglucan, and xylan (the epitope detected by the CCRC-M138 antibody). Full article