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Biopolymers have become prevalent in industries to prevent acid corrosion because of their robust structure and biodegradability. The current research investigates the effectiveness of the biopolymer (+)-arabinogalactan (AG) in inhibiting corrosion on AISI 5140 steel in H2SO4 media, employing a novel approach to experimental design called the custom design of experiment (DoE). Temperature and medium concentration have the greatest effects on the response, according to p-value analysis. The highest inhibitory efficiency (IE) at 50 °C, 0.1 M H2SO4 concentration, and 0.1 g/L of AG is predicted to be 75.57%. Density functional theory-based computational investigations demonstrate the potential of AG as a corrosion inhibitor, with chemisorption being the primary mode of adsorption. AG's adsorption on the metal surface is further confirmed by scanning electron microscope and energy-dispersive X-ray studies. Thus, this study pioneers the application of custom DoE in investigating AG's corrosion inhibition properties on AISI 5140 steel in H2SO4 medium. [ABSTRACT FROM AUTHOR]

Mycobacterium tuberculosis infections continue to pose a significant global health challenge, particularly due to the rise of multidrug-resistant strains, random mycobacterial mutations, and the complications associated with short-term antibiotic regimens. Currently, five approved drugs target cell wall biosynthesis in Mycobacterium tuberculosis. This review provides a comprehensive analysis of these drugs and their molecular mechanisms. Isoniazid, thioamides, and delamanid primarily disrupt mycolic acid synthesis, with recent evidence indicating that delamanid also inhibits decaprenylphosphoryl-β-D-ribose-2-epimerase, thereby impairing arabinogalactan biosynthesis. Cycloserine remains the sole approved drug that inhibits peptidoglycan synthesis, the foundational layer of the mycobacterial cell wall. Furthermore, ethambutol interferes with arabinogalactan synthesis by targeting arabinosyl transferase enzymes, particularly embB- and embC-encoded variants. Beyond these, six promising molecules currently in Phase II clinical trials are designed to target arabinan synthesis pathways, sutezolid, TBA 7371, OPC-167832, SQ109, and both benzothiazinone derivatives BTZ043 and PBTZ169, highlighting advancements in the development of cell wall-targeting therapies. [ABSTRACT FROM AUTHOR]

In response to the restrictions imposed by their epiphytic habit, orchids have developed structural traits that allow greater efficiency in water uptake and use, such as a complex adventitious root system with velamen. The composition of cell wall of this specialized epidermis can be altered according to the substrate to which it is fixed, influencing wall permeability, absorption, and storage of water in roots. The current study aimed to evaluate the cell wall composition of adventitious roots of Vanilla phaeantha (Orchidaceae) that grow attached to the phorophyte, fixed in the soil, or hung free. Immunocytochemical analyses were used to determine the protein, hemicellulose, and pectin composition of the cell walls of aerial and terrestrial roots. We observed that pectins are present in the different tissues of the aerial roots, while in the terrestrial roots, they are concentrated in the cortical parenchyma. The deposition of xyloglucans, extensins, and arabinogalactans was greater in the epidermis of the free side of the roots attached to the phorophyte. The strong labeling of pectins in aerial roots may be related to the influx of water and nutrients, which are generally scarce in this environment. The arrangement of hemicelluloses and proteins with the pectins may be associated with increased cell rigidity and sustainability, a feature of interest for the aerial roots. In summary, the habit of roots can interfere with the non-cellulosic composition of the cell walls of V. phaeantha, possibly related to changes in cell functionality. [ABSTRACT FROM AUTHOR]

Ecologically friendly green synthesis of plasmonic silver and gold nanoparticles with the help of polysaccharides acting both as reducing and capping agents became popular nowadays due to numerous applications of such nanobiocomposites. However, the formation of their core‐shell structures is not at all clear. The core‐shell structures of Au and Ag nanoparticles (NP) synthesized with the help of Siberian Larch arabinogalactan (ARB) is compared. The series of ARB@AgNP is studied with respect to metal content by light scattering (static, dynamic, and electrophoretic one), transmission electron microscopy, FT‐IR, and UV–vis. spectroscopy. The results are compared with those of ARB@AuNP series (J. Phys. Chem C 2011, 115, 24627). Higher redox potential of Au3+ ions is responsible for formation of thicker shells of oxidized and hydrolyzed ARB surrounding AuNPs and more negative zeta‐potentials of these colloids. Contrary to ARB@AgNP colloids with single spherical AgNP in the core, the ARB@AuNP colloids contained a fraction of AuNP dumbbells responsible for the depolarization of scattered light. The position of a slipping plane at which the zeta‐potentials are determined is attributed to the hydrodynamic radii of colloids (Rh). Thus, the decrease of zeta‐potentials with the metal content is explained by the growth of Rh. [ABSTRACT FROM AUTHOR]

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AbstractTwo methods of heat transfer enhancement that have received considerable interest in recent years are nanofluids and heat transfer inserts. Comparatively few studies have evaluated the performance of systems with heat transfer inserts and nanofluids used in combination. In this study, heat transfer enhancement effects of alumina/water (Al2O3/H2O), copper oxide/cetyltrimethyl ammonium bromide/water (CuO/H2O/CTAB), and activated carbon/arabinogalactan/water (C/H2O/ARB) nanofluids both with and without hiTRAN® inserts were investigated using double-pipe heat exchangers in a customized experimental rig. The increase in heat transfer rates due to the nanoparticles (1% by mass of the nanofluids) was comparable in magnitude to the increase observed for the inserts without nanoparticles (i.e. water only), however, the friction factors of the inserts in water were considerably higher than for the nanofluids. The effects of the two heat transfer enhancement methods appeared to be additive when inserts were used in conjunction with nanoparticles. Of the three nanofluids the C/H2O/CTAB nanofluid had the best thermal enhancement assessed using the most commonly applied enhancement index, both with and without inserts. Due to agglomeration of nanoparticles, particularly for the Al2O3/H2O nanofluid that did not have a surfactant, the nanofluids were much less practical to deal with than the inserts. [ABSTRACT FROM AUTHOR]

Objective: The interaction of the eutectic plasticizer—aqua complex "glycerin–water" with sawdust of larch wood of two fractional compositions was studied: a fine fraction (wood flour) and a coarse fraction (sawdust) with a particle size of 1−3 mm. Methods: The methods of optical microscopy were used to study the surface properties of samples, to measure the dynamic viscosity of spent solutions on a Brookfield viscometer; to measure the VGS retention index, a modified Jaime water retention technique was used. The obtained data are compared with the results of previous studies, in which it was shown that arabinogalactan (AG) performs the functions of a eutectic plasticizer in the structure of larch wood and is in the form of an aqua complex «AG–water». Results and Discussion: It was found that the amount of the attached aqua-complex—"glycerin−water" to the samples of larch sawdust corresponds to the amount of AG previously extracted from sawdust. The process of replacing the aqua-complex "AG−water" with the aqua-complex "glycerin–water" is analyzed on the diagram of relaxation states "two polymers–solvent." The experimental results are interpreted on the basis of previously obtained data on the effect of water and glycerin on the relaxation state of polymer components of wood. Conclusions: The fundamental difference between the two eutectic plasticizers is demonstrated: if, when drying larch wood, the destruction of the aqua-complex "AG−water" leads to the transfer of polymer components of wood from a highly elastic to a glassy state, then when using the aqua-complex "glycerin−water" (VGS), water is removed during drying, and the remaining glycerin ensures the preservation of polymer components of wood in a highly elastic state. The possible technological aspects of the revealed patterns are considered. [ABSTRACT FROM AUTHOR]

The effect of chemically synthesized nanocomposites (NCs) of selenium (Se/AG NC), copper oxide (Cu/AG NC) and manganese hydroxide (Mn/AG NC), based on the natural polymer arabinogalactan (AG), on the processes of growth, development and colonization of potato plants in vitro was studied upon infection with the causative agent of potato blackleg—the Gram-negative bacterium Pectobacterium carotovorum—and the causative agent of ring rot—the Gram-positive bacterium Clavibacter sepedonicus (Cms). It was shown that the infection of potatoes with P. carotovorum reduced the root formation of plants and the concentration of pigments in leaf tissues. The treatment of plants with Cu/AG NC before infection with P. carotovorum stimulated leaf formation and increased the concentration of pigments in them. A similar effect was observed when potatoes were exposed to Mn/AG NC, and an increase in growth and root formation was also observed. The infection of plants with Cms inhibited plant growth. Treatment with each of the NCs mitigated this negative effect of the phytopathogen. At the same time, Se/AG and Mn/AG NCs promoted leaf formation. The Se/AG NC increased the biomass of Cms-infected plants. The treatment of plants with NCs before infection showed a decrease in the intensity of the colonization of plants by bacteria. The Se/AG NC had the maximum effect, which is probably due to its high antioxidant capacity. Thus, the NCs are able to mitigate the negative effects of bacterial phytopathogens on vegetation and the intensity of colonization by these bacteria during the infection of cultivated plants. [ABSTRACT FROM AUTHOR]

Drought stress is one of the main factors limiting the high yield and quality of potatoes. Arabinogalactan proteins (AGPs) are an important class of glycoproteins widely present in the cell walls, plasma membranes, and extracellular matrices of higher plants. Among them, fasciclin-like arabinogalactan proteins (FLAs) are involved in plant development, stress responses, and hormone signal regulation. However, little is known about the FLAs gene in potatoes. Based on transcriptome sequencing data, this study screened a drought stress-related candidate FLA gene (StFLA4) through bioinformatics and expression analysis in potatoes. qRT-PCR analysis showed that StFLA4 was induced by drought stress, and its expression decreased with the extension of stress time. Moreover, the relative expression level of StFLA4 in the drought-resistant variety "Kexin 1" was lower than in the drought-sensitive variety "Atlantic". The StFLA4 protein was located in the cell membrane and interacted with nineteen proteins, mainly related to response to environmental stimulus, cellular response to abiotic stimulus, and cell maturation. After heterologous overexpression of StFLA4 in tobacco, the transgenic plants showed more withered leaves than the wild-type tobacco under drought stress. During the drought stress period, the expression level of StFLA4 in the transgenic plants significantly decreased, and the activity of SOD and POD was significantly lower than that of WT. However, the MDA content was higher than that of WT. These results indicated that StFLA4 negatively regulates the response to drought stress. In addition, in the germination test of potato "Variety V7" tubers, it was found that the variation tendency of StFLA4 expression was along with the concentration of arabinogalactan proteins, and it may participate in the regulation of potato tuber germination. This study lays the foundation for elucidating the function and expression pattern of StFLA4 response to drought stress and tuber germination in potatoes. [ABSTRACT FROM AUTHOR]

Aim: To evaluate Hyuganatsu oranges (Citrus tamurana Hort. Ex Tanaka) derived arabinogalactan for bone turnover, we performed a randomized placebo‐controlled trial. Methods: Sixty‐three postmenopausal women were age‐stratified and randomly assigned to receive arabinogalactan‐rich hyuganatsu juice (study group) or a placebo drink (control group) for 90 days. We measured blood tartrate‐resistant acid phosphatase 5b (TRACP5b), type I procollagen N‐terminal propeptide (P1NP), and other bone turnover biomarker levels at baseline, days 45 and 90 (T90) of the intervention, and day 30 of recovery. Cumulative effects were compared between groups using repeated‐measures linear mixed model analysis. The primary endpoint was the difference between the pre‐ and post‐intervention TRACP5b and P1NP levels. Results: Using repeated measures linear mixed model analysis, the study group had significantly lower TRACP5b and P1NP levels at day 90 than the control group (mean [95% confidence interval]; TRACP5b: 310.0 [269.2–350.9] vs. 386.4 [341.2–431.6] mU/dL; P1NP: 53.7 [48.6–58.7] vs. 70.3 [64.1–76.4] ng/mL), whereas other biomarker levels showed no change. Conclusion: Arabinogalactan‐rich Hyuganatsu juice suppressed bone mineral turnover and potentially improved ovarian hormone deficiency‐induced osteoporosis in postmenopausal women. [ABSTRACT FROM AUTHOR]

Coffee is one of the most marketable products worldwide but throughout the production chain, many by-products and waste are generated, e.g., spent coffee grounds (SCG). SCG are considered a promising source of polysaccharides. In the present study, the polysaccharides from SCG were recovered through microwave-assisted extraction. Detailed structural analysis showed that SCG were mainly composed of low-branched galactomannan, followed by various lengths and branches of galactan or arabinogalactan chains whose side chains are randomly ended by glucuronic acid. These findings indicate that glucuronic acid remains attached to the arabinogalactan chain even after coffee roasting and brewing. The investigation confirmed that microwave-assisted extraction, as a green extraction technique, is a promising method for preparing polysaccharides with lower molecular weight. This extraction method ensures the recovery of SCG polysaccharides with potential biological activity without destroying the glucuronic acid at the arabinogalactan chains. [ABSTRACT FROM AUTHOR]

Andrea Bedei,1 Pedro Rocha Cabrera,2 Luis Oliveira,3 Laura Castellini,1 Giulia De Grazia,4 Stefano Remiddi4 1Ophthalmology Department Casa di Cura San Camillo, Forte dei Marmi, Italy; 2Ophthalmology Department Hospital San Juan de Dios Tenerife, Santa Cruz de Tenerife, Spain; 3Ophthalmology Department Hospital Santo Antonio, Porto, Portugal; 4Department of Research and Development, MD Italy, Albano Laziale, ItalyCorrespondence: Stefano Remiddi, MD Italy srl, Department of Research and Development, Via Cancelliera, 12, Albano Laziale, Rome, 00041, Italy, Email stefano.remiddi@md-italy.itPurpose: To assess the efficacy, adherence, and tolerability of a new artificial tear based on arabinogalactan, hyaluronic acid, and trehalose in a population with dry eye disease (DED).Methods: A retrospective, real-world, post-marketing study identified 96 adult patients (aged 18– 80 years) with signs and symptoms of dry eye. These patients received fixed combination therapy with eye drops containing arabinogalactan, hyaluronic acid, and trehalose at various dosing schedules. The data for this study were collected from April 2022 to June 2023. Patients underwent evaluation at baseline (T0) and after a follow-up period of two–three months (T1) using a patient-reported questionnaire.Results: In 96 adult patients (71 women and 25 men) with dry eye due to various conditions, the results indicated a 98% positive response to therapy. This response included improvements in vision (13%), comfort (39%), redness (13%), itching (16%), photophobia (4%), and tearing (14%). Additionally, 61% of the patients experienced 1– 2 hours of comfort following instillation.Conclusion: This real-life post-marketing study demonstrated clinical improvement of signs and symptoms in patients with dry eye disease using a new artificial tear medical device based on arabinogalactan, hyaluronic acid, and trehalose.Keywords: dry eye, real-world study, arabinogalactan, hyaluronic acid, trehalose, post-marketing study

Commensal bacteria and their derivatives hold significant promise as therapeutic interventions to delay aging. However, with the diverse nature of the soil microbiome and the long lifespan of mammalian models, the exploration of the influence of soil bacteria and bacteria‐derived molecules on host aging remains limited. We conducted a lifespan screening in Caenorhabditis elegans using plant root bacterial collection. Our screening identified 8 genera of bacterial isolates capable of extending lifespan, with Mycobacterium sp. Root265 exhibits the most pronounced effect on lifespan extension. Biochemical analysis revealed two specific molecules derived from Root265, polysaccharides (PSs) and arabinogalactan peptidoglycan (AGP), responsible for lifespan extension via daf‐16‐dependent and ‐independent pathways, respectively. Notably, AGP exhibited a unique ability to enhance protein homeostasis effectively. Moreover, polar lipids originating from Root265 were found to extend lifespan while mitigating age‐related BAS‐1 decline in neurons. Intriguingly, even brief exposures to these bioactive compounds were sufficient to achieve the lifespan‐promoting effects. We found diverse beneficial bacteria and anti‐aging active compounds from soil bacteria. These findings highlight the potential of exploring bacterial derivatives as therapies targeting aging without the constraints associated with direct microbial interventions. [ABSTRACT FROM AUTHOR]

Blueberries (Vaccinium corymbosum) undergo significant texture changes during development and ripening, notably a consistent decrease in firmness, which affects fruit quality, consumer preference, transportability, and shelf life. This study examined the composition and structural modifications of the cell wall in five commercially available blueberry varieties with differing firmness levels at harvest. Our approach integrated various biochemical techniques for a comprehensive analysis of cell wall components to elucidate firmness differences at the harvest stage. One of the conclusions was the relationship between a low degree of pectin methylesterification and the presence of increased egg-box structures, which correlated with increased firmness. The data suggest that low-abundance pectins in blueberry cell walls, such as rhamnogalacturonan-I participate in firmness modulation through their side branches or by linking to arabinogalactan proteins. Additionally, the xyloglucan structure can be one of the determinants of fruit firmness. Although, this work provides a broad insight into the relationship between cell wall composition and firmness in blueberry, a more detailed analysis, specifically focusing on pectin and hemicelluloses, would be of significant value. [ABSTRACT FROM AUTHOR]

Deeper understanding of the crosstalk between host cells and Mycobacterium tuberculosis (Mtb) provides crucial guidelines for the rational design of novel intervention strategies against tuberculosis (TB). Mycobacteria possess a unique complex cell wall with arabinogalactan (AG) as a critical component. AG has been identified as a virulence factor of Mtb which is recognized by host galectin-9. Here, we demonstrate that galectin-9 directly inhibited mycobacterial growth through AG-binding property of carbohydrate-recognition domain 2. Furthermore, IgG antibodies with AG specificity were detected in the serum of TB patients. Based on the interaction between galectin-9 and AG, we developed a monoclonal antibody (mAb) screening assay and identified AG-specific mAbs which profoundly inhibit Mtb growth. Mechanistically, proteomic profiling and morphological characterizations revealed that AG-specific mAbs regulate AG biosynthesis, thereby inducing cell wall swelling. Thus, direct AG-binding by galectin-9 or antibodies contributes to protection against TB. Our findings pave the way for the rational design of novel immunotherapeutic strategies for TB control. [ABSTRACT FROM AUTHOR]

Plant cell walls are complex, multifunctional structures, built up of polysaccharides and proteins. The configuration and abundance of cell wall constituents determine cellular elongation and plant growth. The emphasis of this review is on rice, a staple crop with economic importance, serving as model for grasses/cereals. Recent advancements have contributed to a better understanding of the grass/cereal cell wall. This review brings together current knowledge of the organization and metabolism of the rice cell wall, and addresses gaps in the information regarding the cell wall and enzymes involved. Several cell wall fractions, including cellulose, mixed-linkage glucans, and glucuronoarabinoxylans, are well understood in rice and other grasses/grains. Conversely, there are still open questions and missing links in relation to xyloglucans, glucomannans, pectin, lignin, and arabinogalactan proteins. There is still a large and untapped potential to identify carbohydrate-active enzymes (CAZymes), to characterize their activity, and to elucidate their involvement in the metabolism of the mentioned cell wall fractions. This review highlights the involvement of carbohydrate-active enzymes in rice cell wall metabolism, providing an update of current understanding with the aim of demarcating research areas with potential for further investigations. [ABSTRACT FROM AUTHOR]

As dietary needs shift with the growing and aging population, there is a demand for food products that meet nutritional, safety, and tribological requirements while being cost-effective. Seniors must be given significant consideration in new product development. This study examines consumer preferences for arabinogalactan (AG) and beta-glucan (BG) hydrogels with vanilla and coffee-biscuit flavors, using consumer tests (N = 80) and an online survey (N = 852). It focuses on the gels' physical properties, such as texture and viscosity, and their impact on sensory perception. The use of two different gel-forming polysaccharides, each with a unique sensory profile, was observed to affect the sensory properties of the resulting gels and subsequently influence product acceptance. This study analyzed preferences across three age groups: young (18–39 years), middle-aged (40–59 years), and older adults (60+ years). The results showed that seniors preferred AG-based gels. Significant attributes such as the intensity of flavor and bitter taste influenced the overall liking of the gels. Texture also notably impacted preferences. The survey findings revealed statistically significant (p < 0.05) differences in preferences between older adults and younger age groups. Tailoring product development and marketing strategies based on age and sensory preferences could enhance consumer acceptance of edible gels. [ABSTRACT FROM AUTHOR]

Summary: Changes in the plant microbiota composition are intimately associated with the health of the plant, but factors controlling the microbial community in flowers are poorly understood. In this study, we used apple flowers and fire blight as a model system to investigate the effects of floral microbiota and microbial competition on disease development and suppression.To compare changes in microbial flora with the RNA expression patterns of plants, the flower samples were collected in three different flowering stages (Bud, Popcorn, and Full‐bloom). Using advanced sequencing technology, we analyzed the data and conducted both in vitro and in vivo experiments to validate our findings.Our results show that the Erwinia amylovora use arabinogalactan, which is secreted on the flowers, for early colonization of apple flowers. Pantoea agglomerans was more competitive for arabinogalactan than E. amylovora. Additionally, P. agglomerans suppressed the expression of virulence factors of E. amylovora by using arabinose, which is a major component of arabinogalactan, which induces virulence gene expression.The present data provide new insights into developing control strategies for diverse plant diseases, including fire blight, by highlighting the importance of nutrients in disease development or suppression. [ABSTRACT FROM AUTHOR]

The Mycobacterium cell wall is a capsule‐like structure comprising of various layers of biomolecules such as mycolic acid, peptidoglycans, and arabinogalactans, which provide the Mycobacteria a sort of cellular shield. Drugs like isoniazid, ethambutol, cycloserine, delamanid, and pretomanid inhibit cell wall synthesis by inhibiting one or the other enzymes involved in cell wall synthesis. Many enzymes present across these layers serve as potential targets for the design and development of newer anti‐TB drugs. Some of these targets are currently being exploited as the most druggable targets like DprE1, InhA, and MmpL3. Many of the anti‐TB agents present in clinical trials inhibit cell wall synthesis. The present article covers a systematic perspective of developing cell wall inhibitors targeting various enzymes involved in cell wall biosynthesis as potential drug candidates for treating Mtb infection. [ABSTRACT FROM AUTHOR]

The hemocompatibility of arabinogalactan, betulin and its derivatives was evaluated in vitro and samples suitable for creation of nanostructures or materials in contact with blood were selected. The prospects of arabinogalactan as a component of the construct (nanostructure) for drug delivery are due to the fact that it did not affect blood/plasma coagulation (at concentrations of 0.0033-3.333 mg/ml and 0.00465-4.65 mg/ml, respectively), platelet aggregation (0.00182-0.182 mg/ml), and demonstrated the degree of erythrocyte hemolysis less than 3%. Sodium salt of betulin monosulfate, diarginine salt of betulin disulfate (up to 0.465 mg/ml), and especially betulin and allobetulin formate with procoagulant properties (degree of hemolysis less than 2%) can be used to create a material, for example, sponge, gel, active against blood coagulation. [ABSTRACT FROM AUTHOR]

Bifidobacterium adolescentis gene BAD_1527 has previously been suggested to code for a β-xylosidase (Kobayashi et al., Mar Drugs 18:174, 2020). Our detailed investigation of the substrate specificity of the GH43_22 protein using a wide spectrum of natural and artificial substrates showed that the enzyme hydrolyzed neither linear xylooligosaccharides nor glucuronoxylan. Xylose was released only from the artificial 4-nitrophenyl β-D-xylopyranoside (1.58 mU/mg). The corresponding α-L-arabinofuranoside was by three orders of magnitude better substrate (2.17 U/mg). Arabinose was the only monosaccharide liberated from arabinoxylan and α-1,3- or α-1,2-singly arabinosylated xylooligosaccharides. Moreover, the enzyme efficiently debranched sugar beet arabinan and singly arabinosylated α-1,5-L-arabinooligosaccharides, although short linear α-1,5-L-arabinooligosaccharides were also slowly degraded. On the other hand, debranched arabinan, arabinogalactan as well as 2,3-doubly arabinosylated main chain residues of arabinan and arabinoxylan did not serve as substrates. Thus, the enzyme encoded by the BAD_1527 gene is a typical α-L-arabinofuranosidase of AXH-m specificity. Key points: BAD_1527 gene encodes a protein releasing xylose from NPX, but not natural substrates L-Arabinose is released from natural substrates, similarly to other GH43_22 members The enzyme debranches arabinoxylan, branched arabinan and derived oligosaccharides [ABSTRACT FROM AUTHOR]

Cactus cladodes have been emerged as one of the most popular plant-based flocculants. They have been listed as a promising natural alternative to the noxious synthetic flocculants. However, practical application of this bio-flocculant is still hampered by some questions concerning their formulations' stability, active agents therein and their flocculating performance. Thus, in this study, three cactus formulations, namely, cactus juice (CJ), cactus lyophilized powder (CLP) and oven-dried powder (CDP) were subjected to a physicochemical characterization to provide an in-depth understanding of the main flocculation active agents and distinguish the suitable preparation method promoting bio-flocculants' stability and effectiveness. Therefore, their flocculating activity was evaluated in treating a model-colored effluent, a crystal violet (CV) dye solution. The obtained results show that the three cactus formulations exhibit a significant sugars content with considerable calcium amounts. The highest sugars content was registered for CLP thanks to the efficacy of lyophilization method to maintain their stability. Furthermore, the main flocculating active compound was identified as an arabinogalactan composed of long polygalacturonic acid chain backbones with branches of neutral sugar residues involving mostly the arabinose. As for the color removal performance, an outstanding CV removal exceeding 99% was found using CLP under alkaline pH. It was occurred through charge neutralization and bridging mechanisms. Hence, based on these groundbreaking results, the application of cactus formulation-based flocculants, especially the lyophilized one is highly recommended to ensure a clean, eco-friendly and sustainable wastewater treatment approach. [ABSTRACT FROM AUTHOR]

Species in the genus Utricularia are carnivorous plants that prey on invertebrates using traps of leaf origin. The traps are equipped with numerous different glandular trichomes. Trichomes (quadrifids) produce digestive enzymes and absorb the products of prey digestion. The main aim of this study was to determine whether arabinogalactan proteins (AGPs) occur in the cell wall ingrowths in the quadrifid cells. Antibodies (JIM8, JIM13, JIM14, MAC207, and JIM4) that act against various groups of AGPs were used. AGP localization was determined using immunohistochemistry techniques and immunogold labeling. AGPs localized with the JIM13, JIM8, and JIM14 epitopes occurred in wall ingrowths of the pedestal cell, which may be related to the fact that AGPs regulate the formation of wall ingrowths but also, due to the patterning of the cell wall structure, affect symplastic transport. The presence of AGPs in the cell wall of terminal cells may be related to the presence of wall ingrowths, but processes also involve vesicle trafficking and membrane recycling, in which these proteins participate. [ABSTRACT FROM AUTHOR]

The cell envelope fortifies bacterial cells against antibiotics and other insults. Species in the Mycobacteriales order have a complex envelope that includes an outer layer of mycolic acids called the mycomembrane (MM) and a cell wall composed of peptidoglycan and arabinogalactan. This envelope architecture is unique among bacteria and contributes significantly to the virulence of pathogenic Mycobacteriales like Mycobacterium tuberculosis. Characterization of pathways that govern envelope biogenesis in these organisms is therefore critical in understanding their biology and for identifying new antibiotic targets. To better understand MM biogenesis, we developed a cell sorting-based screen for mutants defective in the surface exposure of a porin normally embedded in the MM of the model organism Corynebacterium glutamicum. The results revealed a requirement for the conserved σD envelope stress response in porin export and identified MarP as the site-1 protease, respectively, that activate the response by cleaving the membrane-embedded anti-sigma factor. A reporter system revealed that the σD pathway responds to defects in mycolic acid and arabinogalactan biosynthesis, suggesting that the stress response has the unusual property of being induced by activating signals that arise from defects in the assembly of two distinct envelope layers. Our results thus provide new insights into how C. glutamicum and related bacteria monitor envelope integrity and suggest a potential role for members of the σD regulon in protein export to the MM. Author summary: Bacteria within the Mycobacteriales order, which includes the pathogen Mycobacterium tuberculosis, have a unique multilayered cell surface architecture. How they sense and respond to defects in the construction of this distinct envelope to maintain homeostasis remains poorly understood. Here, we used the model organism Corynebacterium glutamicum to reveal that the conserved σD envelope stress response pathway responds to two distinct signals resulting from defects in different envelope layers. The results provide new insight into how members of the Mycobacteriales monitor the integrity of their surface and pave the way for the identification of novel vulnerabilities in envelope biogenesis that may be useful for targeting with antibiotics. [ABSTRACT FROM AUTHOR]

The widening of possible areas of practical uses for zero-valent tellurium nanoparticles (Te0NPs) from biomedicine to optoelectronic and thermoelectric applications determines the actuality of the development of simple and affordable methods for their preparation. Among the existing variety of approaches to the synthesis of Te0NPs, special attention should be paid to chemical methods, and especially to "green" approaches, which are based on the use of precursors of tellurium in their powder bulk form and natural galactose-containing polysaccharides—arabinogalactan (Ar-Gal), galactomannan—(GM-dP) and κ-carrageenan (κ-CG) acting as ligands stabilizing the surface of the Te0NPs. The use of basic-reduction system "N2H4 H2O-NaOH" for preliminary activation of bulk-Te and Ar-Gal, GM-dP and κ-CG allowed us to obtain in aqueous medium a number of stable nanocomposites consisting of Te0NPs stabilized by the polysaccharides' macromolecules. By varying the precursor ratio, different morphologies of nanoparticles were obtained, ranging from spheres at a polysaccharide/Te ratio of 100:1 to rice-like at a 10:1 ratio. The type (branched, combed, or linear sulfated) of polysaccharide and its molecular weight value determined the size of the nanoparticles. Thus, the galactose-containing polysaccharides that were selected for this study may be promising renewable materials for the production of water-soluble Te0NPs with different morphology on this basis. [ABSTRACT FROM AUTHOR]

Arabinogalactan (AG), extracted from larch wood, is a β-1,3-galactan backbone and β-1,6-galactan side chains with attached α-1-arabinofuranosyl and β-1-arabinopyranosyl residues. Although the structural characteristics of arabinogalactan II type have already been studied, its functionalization using 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) oxidation remains a promising avenue. In this study, the oxidation of AG, a neutral polysaccharide, was carried out using the TEMPO/NaBr/NaOCl system, resulting in polyuronides with improved functional properties. The oxidation of AG was controlled by analyzing portions of the reaction mixture using spectrophotometric and titration methods. To determine the effect of the TEMPO/NaBr/NaOCl system, air-dried samples of native and oxidized AG were studied by Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, as well as by gel permeation chromatography. Compounds that model free (1,1-diphenyl-2-picrylhydrazyl (DPPH)) and hydroxyl radicals (iron(II) sulfate, hydrogen peroxide, and salicylic acid) were used to study the antioxidant properties. It was found that, in oxidized forms of AG, the content of carboxyl groups increases by 0.61 mmol compared to native AG. The transformation of oxidized AG into the H+ form using a strong acid cation exchanger leads to an increase in the number of active carboxyl groups to 0.76 mmol. Using FTIR spectroscopy, characteristic absorption bands (1742, 1639, and 1403 cm−1) were established, indicating the occurrence of oxidative processes with a subsequent reduction in the carboxyl group. The functionality of AG was also confirmed by gel permeation chromatography (GPC), which is reflected in an increase in molecular weights (up to 15,700 g/mol). A study of the antioxidant properties of the oxidized and protonated forms of AG show that the obtained antioxidant activity (AOA) values are generally characteristic of polyuronic acids. Therefore, the TEMPO oxidation of AG and other neutral polysaccharides can be considered a promising approach for obtaining compounds with the necessary controlled characteristics. [ABSTRACT FROM AUTHOR]

Abstract Background The Citrus reticulata Blanco peels have been widely adopted as functional food or nutraceuticals for thousands of years. In our study, two polysaccharides from the C. reticulata Blanco peels were obtained and named as CRP-WA and CRP-02A, respectively. After characterization by monosaccharide composition, methylation and NMR, chemical structures of CRP-WA and CRP-02A were elucidated. Results As a result, CRP-WA with Mw of 32.8 kDa was an arabinogalactan polysaccharide composed of (β1 → 3) (β1 → 3,6)-D-Galp, (β1 → 4)-D-Manp and (β1 → 4)-D-Glcp units in the backbone. The CRP-02A with Mw of 70.5 kDa was an arabinogalacturonan type pectin formed by (α1 → 4) (α1 → 3,4)-D-GalpA units in the backbone. Moreover, the surface morphologies and rheological properties of CRP-WA and CRP-02A were quite different from each other. Both of these two polysaccharides possessed good antioxidant activities and immunoregulatory effects on RAW 264.7 cells, in which CRP-02A behaved remarkable antioxidant feature, whereas CRP-WA showed relatively high immunoregulatory activity. Conclusion Our study will provide fundamental information for C. reticulata Blanco-based nutritional foods development. Graphical Abstract

The effect of chemically synthesized nanocomposites (NCs) of selenium (Se/AG NC), copper oxide (Cu/AG NC) and manganese hydroxide (Mn/AG NC), based on the natural polymer arabinogalactan (AG), on the processes of growth, development and colonization of potato plants in vitro was studied upon infection with the causative agent of potato blackleg—the Gram-negative bacterium Pectobacterium carotovorum—and the causative agent of ring rot—the Gram-positive bacterium Clavibacter sepedonicus (Cms). It was shown that the infection of potatoes with P. carotovorum reduced the root formation of plants and the concentration of pigments in leaf tissues. The treatment of plants with Cu/AG NC before infection with P. carotovorum stimulated leaf formation and increased the concentration of pigments in them. A similar effect was observed when potatoes were exposed to Mn/AG NC, and an increase in growth and root formation was also observed. The infection of plants with Cms inhibited plant growth. Treatment with each of the NCs mitigated this negative effect of the phytopathogen. At the same time, Se/AG and Mn/AG NCs promoted leaf formation. The Se/AG NC increased the biomass of Cms-infected plants. The treatment of plants with NCs before infection showed a decrease in the intensity of the colonization of plants by bacteria. The Se/AG NC had the maximum effect, which is probably due to its high antioxidant capacity. Thus, the NCs are able to mitigate the negative effects of bacterial phytopathogens on vegetation and the intensity of colonization by these bacteria during the infection of cultivated plants.

Arabinose and galactose are major, rapidly metabolized components of marine particulate and dissolved organic matter. In this study, we observed for the first time large microbiomes for the degradation of arabinogalactan and report a detailed investigation of arabinogalactan utilization by the flavobacterium Maribacter sp. MAR_2009_72. Cellular extracts hydrolysed arabinogalactan in vitro. Comparative proteomic analyses of cells grown on arabinogalactan, arabinose, galactose, and glucose revealed the expression of specific proteins in the presence of arabinogalactan, mainly glycoside hydrolases (GH). Extracellular glycan hydrolysis involved five alpha- l -arabinofuranosidases affiliating with glycoside hydrolase families 43 and 51, four unsaturated rhamnogalacturonylhydrolases (GH105) and a protein with a glycoside hydrolase family-like domain. We detected expression of three induced TonB-dependent SusC/D transporter systems, one SusC, and nine glycoside hydrolases with a predicted periplasmatic location. These are affiliated with the families GH3, GH10, GH29, GH31, GH67, GH78, and GH115. The genes are located outside of and within canonical polysaccharide utilization loci classified as specific for arabinogalactan, for galactose-containing glycans, and for arabinose-containing glycans. The breadth of enzymatic functions expressed in Maribacter sp. MAR_2009_72 as response to arabinogalactan from the terrestrial plant larch suggests that Flavobacteriia are main catalysts of the rapid turnover of arabinogalactans in the marine environment. [ABSTRACT FROM AUTHOR]

A convergent synthesis α-(1→3)-, α-(1→5), β-(1→2)-linked hexaarabinofuranoside related to the terminal fragment of lipoarabinomannan (LAM) and arabinogalactan of mycobacteria as a glycoside with 4-(3-azidopropoxy)phenyl aglycone was accomplished. 4-(3-Azidopropoxy)phenyl aglycone belongs to the class of Janus aglycones, which can be used as both a temporary protective group for the anomeric position of the carbohydrate and a (pre)spacer for the synthesis of neoglycoconjugates. The key step of the synthesis is the formation of 1,2-trans glycosidic linkage with the use of Ara-β-(1→2)-Ara p-tolylthioarabinofuranoside bearing five triisopropylsilyl groups. [ABSTRACT FROM AUTHOR]

Arabinogalactan proteins (AGPs) are proteoglycans with an unusual molecular structure characterised by the presence of a protein part and carbohydrate chains. Their specific properties at different stages of the fruit ripening programme make AGPs unique markers of this process. An important function of AGPs is to co-form an amorphous extracellular matrix in the cell wall-plasma membrane continuum; thus, changes in the structure of these molecules can determine the presence and distribution of other components. The aim of the current work was to characterise the molecular structure and localisation of AGPs during the fruit ripening process in transgenic lines with silencing and overexpression of SlP4H3 genes (prolyl 4 hydroxylase 3). The objective was accomplished through comprehensive and comparative in situ and ex situ analyses of AGPs from the fruit of transgenic lines and wild-type plants at specific stages of ripening. The experiment showed that changes in prolyl 4 hydroxylases (P4H3) activity affected the content of AGPs and the progress in their modifications in the ongoing ripening process. The analysis of the transgenic lines confirmed the presence of AGPs with highmolecular weights (120-60 kDa) at all the examined stages, but a changed pattern of the molecular features of AGPswas found in the last ripening stages, compared to WT. In addition to the AGP molecular changes, morphological modifications of fruit tissue and alterations in the spatio-temporal pattern of AGP distribution at the subcellular level were detected in the transgenic lines with the progression of the ripening process. The work highlights the impact of AGPs and their alterations on the fruit cell wall and changes in AGPs associated with the progression of the ripening process. [ABSTRACT FROM AUTHOR]

The interaction of pectin and arabinogalactan macromolecules in aqueous solutions has been studied. It is shown that polymer complexes are formed due to hydrogen bonding between macromolecules. Crosslinking of the polymer complex by Са2+ ions leads to the formation of hydrogels whose properties are considerably determined by the content of arabinogalactan. At low concentrations of Са2+ ions (from 0.05 to 0.15 wt %), the introduction of arabinogalactan contributes to an increase in shear modulus and crosslink concentration and results in a reduction in polymer network sizes compared with hydrogels based on native pectin. With increasing arabinogalactan content the contribution of Fick's diffusion to swelling of the synthesized hydrogels grows. [ABSTRACT FROM AUTHOR]

Expansins are small proteins that play a key role in modifying the structure of the cell wall during various physiological processes, in particular cell growth by elongation. Expansins are encoded by a large multigene family and are divided into four subfamilies, the main ones being alpha- and beta-expansins; the latter have received special development in cereals. Expansins are thought to modify the interactions of cellulose with xyloglucan (alpha-expansins) or with arabinoxylan (beta-expansins). At the same time, expansins do not have catalytic activity, the specific mechanism of their action is unclear, same as the physiological significance of such a wide variety of isoforms. To study the expression patterns of individual expansins, we conducted a transcriptomic analysis of all expansin genes identified in the maize genome using a convenient model system—zones of the maize growing primary root that differ in the stage of cell development and the composition of their cell walls. Of the 91 maize expansin genes, 67 were expressed in the root, and most expansin genes were characterized by a narrow range of zones with maximum transcript levels. Using a glycoarray containing 183 polysaccharides from the cell walls of plants of various species, we demonstrated that recombinant expansins AtEXPA1 and AtEXPB1 are able to bind to arabinogalactans and rhamnogalacturonans I and a number of other cell wall polysaccharides, which expands the list of their potential carbohydrate targets. Differences in the specificity of the interaction of alpha- and beta-expansins with various polysaccharides, both quantitatively and qualitatively, have been demonstrated. It has been hypothesized that the abundance of expansins in one plant organism and the fine regulation of their expression can be explained, at least in part, by the specific binding of individual expansins to specific cell wall polysaccharides. [ABSTRACT FROM AUTHOR]

The study investigates carbon-containing coatings of 3d-metals (Ni, Co, Fe) produced by chemical deposition method using arabinogalactan. The coatings were analyzed using X-ray diffraction, FMR, and M(H) magnetometry. Measurement of M(H) in plane and perpendicular to the plane of the magnetic coatings allowed determining the distribution of demagnetizing factor in the studied coatings. The obtained distributions of the demagnetizing factor were used to analyze the angular dependences of the ferromagnetic resonance field. The values of magnetization and perpendicular anisotropy field were estimated. The paper illustrates the effect of texture on the magnetic parameters. [ABSTRACT FROM AUTHOR]

Background: The Citrus reticulata Blanco peels have been widely adopted as functional food or nutraceuticals for thousands of years. In our study, two polysaccharides from the C. reticulata Blanco peels were obtained and named as CRP-WA and CRP-02A, respectively. After characterization by monosaccharide composition, methylation and NMR, chemical structures of CRP-WA and CRP-02A were elucidated. Results: As a result, CRP-WA with Mw of 32.8 kDa was an arabinogalactan polysaccharide composed of (β1 → 3) (β1 → 3,6)-D-Galp, (β1 → 4)-D-Manp and (β1 → 4)-D-Glcp units in the backbone. The CRP-02A with Mw of 70.5 kDa was an arabinogalacturonan type pectin formed by (α1 → 4) (α1 → 3,4)-D-GalpA units in the backbone. Moreover, the surface morphologies and rheological properties of CRP-WA and CRP-02A were quite different from each other. Both of these two polysaccharides possessed good antioxidant activities and immunoregulatory effects on RAW 264.7 cells, in which CRP-02A behaved remarkable antioxidant feature, whereas CRP-WA showed relatively high immunoregulatory activity. Conclusion: Our study will provide fundamental information for C. reticulata Blanco-based nutritional foods development. [ABSTRACT FROM AUTHOR]

Using spectral ensemble methods (DLS, optical and luminescence spectroscopy) and the transmission electron microscopy as reference method, the dynamics of selenium nanoparticles synthesis from sodium bis(2-phenylethyl)diselenophosphinate (DSePhNa) organophosphorus precursor in aqueous solution of polysaccharide matrix arabinogalactan (Ar-Gal) was studied. It was shown that the addition of hydrogen peroxide to the aqueous solution of DSePhNa initiates its oxidation with release of Se0 atoms with formation of selenium nanoparticles already by 10 s of synthesis. This stage identified by isolation of a fraction corresponding to nanoparticles in the size distribution. Full involvement of Ar-Gal macromolecules in the stabilization of formed selenium nanoparticles is completed by 8 min of the synthesis, which is accompanied by a narrowing of the size distribution of the formed nanoparticles. All basic stages of the particle formation and growth, as well as Ostwald ripening, in the case of long-term sample storage have been recorded by both TEM and the spectral ensemble methods. In the paper the most probable mechanism of selenium nanoparticle formation under the selected synthesis conditions is explained based on all the data obtained on the nature of nanoparticle size distribution. Besides, the possibility of using these spectral methods to estimate the dynamics of nanoparticle synthesis is discussed. Highlights: Spectral ensemble methods (DLS, optical and luminescence spectroscopy) can be used to evaluate the dynamics of nanoparticle synthesis in solution. The formation of nanoparticles is identified almost instantly (by 10 s of synthesis) by the separation of the small particle fraction, in the size distributions obtained from all spectral methods and confirmed by TEM. The nature (symmetry, modality) of the size distribution of Ar-Gal-stabilized SeNPs depends on the synthesis step and varies strongly over time until the completion stage of the process is reached. Prolonged storage of aqueous solution of Ar-Gal-stabilized SeNPs is characterized by non-stationary of state and is accompanied by a number of processes typical of Ostwald ripening leading also to changes in the character of disperse distribution of particles identified by all used spectral and TEM methods. [ABSTRACT FROM AUTHOR]

Novel copper-containing bionanocomposites based on the natural raw arabinogalactan have been obtained as universal effective agents against phytopathogen Clavibacter sepedonicus and development stimulants of agricultural plants. Thus, the use of such nanosystems offers a solution to the tasks set in biotechnology while maintaining high environmental standards using non-toxic, biocompatible, and biodegradable natural biopolymers. The physicochemical characteristics of nanocomposites were determined using a number of analytical methods (elemental analysis, transmission electron microscopy and spectroscopic parameters of electron paramagnetic resonance, UV–visible, etc.). The results of the study under the influence of the nanocomposites on the germination of soybean seeds (Glycine max L.) and the vegetation of potatoes (Solanum tuberosum L.) showed the best results in terms of biometric indicators. It is especially worth noting the pronounced influence of the nanocomposite on the development of the root system, and the increase in the mass of the potato root system reached 19%. It is also worth noting that the nanocomposites showed a stimulating effect on the antioxidant system and did not have a negative effect on the content of pigments in potato tissues. Moreover, the resulting bionanocomposite showed a pronounced antibacterial effect against the phytopathogenic bacterium. During the co-incubation of phytopathogen Clavibacter sepedonicus in the presence of the nanocomposite, the number of cells in the bacterial suspension decreased by up to 40% compared to that in the control, and a 10% decrease in the dehydrogenase activity of cells was also detected. [ABSTRACT FROM AUTHOR]

In this study, carboxymethylcellulose and arabinogalactan were used to create an interpenetrating network (IPN) hydrogel system in the presence of AlCl3 alone or in combination with ZnSO4 salts. Ionotropic gelation caused the polymer sol droplets to transform into hydrogel particles in the presence of salts. The impact of salts on hydrogel properties was evaluated in terms of morphology, drug entrapment efficiency, swelling, and drug release kinetics. The cellulose IPN hydrogel particles containing 50% arabinogalactan looked spherical with evidence of surface folding when treated with AlCl3. Surface folding was reduced by an additional treatment with ZnSO4. Following treatment of the IPN particles with dual salts, a maximum drug entrapment efficiency of 88.77% was obtained. Surface erosion, as seen with aluminum‐IPN hydrogel particles, was minimized with the use of mixed salts as gelation medium. Furthermore, the use of mixed salts allowed the hydrogel particles to swell and consistently release simvastatin in simulated gastrointestinal fluids for up to 9 h. Thermal and x‐ray analyses revealed that the crystallinity of the drug reduced considerably after entrapment in the IPN hydrogel matrix. The infrared spectra analysis did not indicate any evidence of drug polymer interaction. The release of drug from the IPN hydrogel particles followed non‐Fickian diffusion mechanism. The dual metallic salts were found to be effective in creating physically stable cellulose‐arabinogalactan IPN hydrogel particles for sustained release of simvastatin in a varying pH environment of gastrointestinal tract. Highlights: Dual inorganic salts allowed synthesis of cellulose/arabinogalactan hydrogelAdditional use of ZnSO4 improved surface morphology of hydrogel particlesCompatible environment of hydrogels allowed more than 88% drug entrapmentConcentration of neutral arabinogalactan was crucial in dictating drug releaseMixed salts controlled swelling and release of simvastatin from hydrogels [ABSTRACT FROM AUTHOR]

The arabinogalactan in the representative softwood biomass of larch was degraded using an environmentally friendly hydrogen peroxide and vitamin C (H2O2-VC) system to improve its immunomodulatory activity. Through the H2O2-VC degradation mechanism, hydroxyl radicals are generated, which then target the hydrogen atoms within polysaccharides, resulting in the breaking of glycosidic bonds. Given the impact of oxidative degradation on polysaccharides, we identified three specific arabinogalactan degradation products distinguished by their arabinosyl side chain compositions. The primary structures of the degradation products were investigated using Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Congo red staining showed that the degradation products were absent in the triple-helix structure. The results of the in vitro immunological experiments indicated that an appropriate reduction in the molar ratio of arabinose to galactose enhanced the immunostimulatory effects on RAW 264.7 cells. In addition, the immunostimulatory pathway mediated by arabinogalactan was explored by toll-like receptor 4 (TLR4) inhibitor (TAK-242) These findings provide novel insights into the understanding of the relationship between the structure of arabinogalactan and its biological activity.

As dietary needs shift with the growing and aging population, there is a demand for food products that meet nutritional, safety, and tribological requirements while being cost-effective. Seniors must be given significant consideration in new product development. This study examines consumer preferences for arabinogalactan (AG) and beta-glucan (BG) hydrogels with vanilla and coffee-biscuit flavors, using consumer tests (N = 80) and an online survey (N = 852). It focuses on the gels’ physical properties, such as texture and viscosity, and their impact on sensory perception. The use of two different gel-forming polysaccharides, each with a unique sensory profile, was observed to affect the sensory properties of the resulting gels and subsequently influence product acceptance. This study analyzed preferences across three age groups: young (18–39 years), middle-aged (40–59 years), and older adults (60+ years). The results showed that seniors preferred AG-based gels. Significant attributes such as the intensity of flavor and bitter taste influenced the overall liking of the gels. Texture also notably impacted preferences. The survey findings revealed statistically significant (p < 0.05) differences in preferences between older adults and younger age groups. Tailoring product development and marketing strategies based on age and sensory preferences could enhance consumer acceptance of edible gels.