Synthesis Of Oligosaccharides Research Articles

Integrated multiple-omics reveals the regulatory mechanism underlying the effects of homologous Bacillus tequilensis (GCB-3) on growth performance of grass carp (Ctenopharyngodon idellus)

The purpose of this study was to investigate the regulatory mechanism of Bacillus tequilensis (GCB-3) in improving the growth performance of grass carp by microbiome and targeted metabolomics analysis. Fish were fed with different amounts of GCB-3 including B0 (0 CFU/g), B6 (1×106 CFU/g), B7 (1×107 CFU/g), B8 (1×108 CFU/g), and B9 (1×109 CFU/g) for 8 weeks. The results indicate that with the increase of dietary GCB-3 concentration, grass carp showed a significant linear trend in growth performance, and appetite factors showed a significant linear and quadratic trend, the growth performance and appetite-promoting factors in the B8 group reach their maximum value in the B8 group. Microbiome analysis found that Proteobacteria and Actinobacteria were the most abundant phylum in the gut microbiota of grass carp. The functional potential predicted that GCB-3 affected the synthesis and degradation of carbohydrates, amino acids, fatty acids and lipids. It found that GCB-3 also affected the tricarboxylic acid (TCA) cycle VII (acetate-producers) pathway. The results of targeted metabolomics showed a significant linear and quadratic increase in intestinal acetate with GCB-3 concentration and a maximum in the B8 group. The results of the correlation analysis showed a significant positive correlation between Actinobacteria abundance and acetic acid content, and also between TCA cycle VII (acetate-producers) pathway abundance and Actinobacteria abundance and acetic acid content. In B8 group, grass carp showed a faster regulation speed of blood glucose levels after glucose injection, and the GLP-1 content remained stable. The activities of glycolytic enzymes, lipolytic enzymes, protein metabolism enzymes, and their related mRNA expression levels in grass carp showed a linear or quadratic increasing trend. However, the expression levels of gluconeogenic enzymes and fatty acid synthesis enzyme related mRNA showed an opposite trend. In summary, the addition of 1×108 CFU/g GCB-3 in grass carp feed can improve the abundance of dominant bacterial phyla in the intestine, especially Actinobacteria, increase the concentration of intestinal acetate, provide substrate for the TCA cycle VII (acetate-producers) pathway, thereby regulating the nutrient metabolism of grass carp and ultimately promoting growth.

Kinetics and products of Thermotoga maritima β-glucosidase with lactose and cellobiose.

Galacto-oligosaccharides (GOS) are prebiotic compounds that are mainly used in infant formula to mimic bifidogenic effects of mother's milk. They are synthesized by β-galactosidase enzymes in a trans-glycosylation reaction with lactose. Many β-galactosidase enzymes from different sources have been studied, resulting in varying GOS product compositions and yields. The in vivo role of these enzymes is in lactose hydrolysis. Therefore, the best GOS yields were achieved at high lactose concentrations up to 60%wt, which require a relatively high temperature to dissolve. Some thermostable β-glucosidase enzymes from thermophilic bacteria are also capable of using lactose or para nitrophenyl-galactose as a substrate. Here, we describe the use of the β-glucosidase BglA from Thermotoga maritima for synthesis of oligosaccharides derived from lactose and cellobiose and their detailed structural characterization. Also, the BglA enzyme kinetics and yields were determined, showing highest productivity at higher lactose and cellobiose concentrations. The BglA trans-glycosylation/hydrolysis ratio was higher with 57%wt lactose than with a nearly saturated cellobiose (20%wt) solution. The yield of GOS was very high, reaching 72.1%wt GOS from lactose. Structural elucidation of the products showed mainly β(1 → 3) and β(1 → 6) elongating activity, but also some β(1 → 4) elongation was observed. The β-glucosidase BglA from T. maritima was shown to be a very versatile enzyme, producing high yields of oligosaccharides, particularly GOS from lactose. KEY POINTS: • β-Glucosidase of Thermotoga maritima synthesizes GOS from lactose at very high yield. • Thermotoga maritima β-glucosidase has high activity and high thermostability. • Thermotoga maritima β-glucosidase GOS contains mainly (β1-3) and (β1-6) linkages.

Management of Secondary Metabolite Synthesis and Biomass in Basil (Ocimum basilicum L.) Microgreens Using Different Continuous-Spectrum LED Lights.

Different LED light spectra (LS) are absorbed by different plant photoreceptors and can control biomass and plant secondary metabolite synthesis. In this study, the effects of continuous-spectrum LED lights (red, blue, white, red + blue, and 12 h blue + 12 h red) on the production value, antioxidant compounds, and biomass of basil (Ocimum basilicum L.) microgreens (Red Rubin, Violeto, and Kapoor cultivars and the Ablagh genotype) were investigated. The results showed significant effects of LS on cultivar (Cv) and the interaction of LS and Cv on the studied traits. The highest quantitys of chlorophyll a, total chlorophyll, and nitrate were obtained in Violeto under blue lighting. Red lighting enhanced starch synthesis in Red Rubin and flavonoids in the Violeto Cv. The highest biomass (4.54 kg m-2) was observed in the Ablagh genotype and the highest carbohydrate synthesis in Violeto Cv in the red + blue treatment. The highest anthocyanin content (26.33 mg 100 g-1 FW) was observed for Red Rubin Cv under 12 h blue + 12 h red light. The greatest antioxidant capacity (83.57% inhibition), the highest levels of phenolic compounds (2027.25 mg GA 100 g-1 FW), vitamin C (405.76 mg 100 g-1 FW), proline, antioxidant potential composite index (APCI), and the greatest production values were obtained for the Ablagh genotype under blue lighting. Taken together, the experiment findings indicate that growing the Ablagh genotype under continuous blue lighting can increase the antioxidant capacity, phenolic compounds, and vitamin C and that this LED light spectrum can be used as a practical method to produce basil microgreens with high nutritional health value.

Glycan synthesis: An update

Carbohydrate synthesis presents several challenges due to the intricate nature of molecules and their complex structures. Since certain pathogens are difficult to culture in the laboratory under some circumstances, and the isolation of glycans in pure structural forms is an arduous undertaking, the medicinal chemistry approach offers a fascinating and attractive option. The efforts being made to develop an automated system for oligosaccharide synthesis are expected to produce immense effects and revolutionize the understanding of the role of carbohydrates in biological systems. Glycovaccines aid in saving millions of lives around the world annually by protecting children and adults from bacterial infections. These vaccines further expand the therapeutic armamentarium against several microbial infectious diseases. This review highlights the different clinical applications of glycan and the progress made in their synthetic process.

Improve Cannabis sativa micropropagation through increasing air change rate in photoautotrophic and traditional tissue culture

Micropropagation is essential for pathogen-free plant materials. However, the conventional in-vitro micropropagation approach poses challenges for optimal growth and development. This study enhances Cannabis sativa micropropagation by implementing a photoautotrophic tissue culture with increased air change rates. This method relies exclusively on photosynthesis for carbohydrate synthesis, eliminating the need for exogenous sugar supplementation. To overcome the limitations of conventional in vitro culture, the photoautotrophic culture requires higher air exchange in the vessel to supply CO2 for photosynthesis. The research evaluates the effects of varying air change rates, comparing conventional tissue culture (TC) with photoautotrophic micropropagation (PAM). Nodal explants, each with 3–4 fully expanded leaves, were transferred to PAM or TC media in Magenta boxes, undergoing four distinct air change rate treatments: 0.5 (control), 4.1, 7.9, and 14.5 air change per hour. Magenta boxes were placed under controlled chamber conditions, including a photosynthetic photon flux density of 100 µmol·m−2·s−1, 18-hour photoperiod, 25 °C temperature, 70 % relative humidity, and CO2 concentration of 553 µmol·mol−1; data were collected after a 28-day period. Increasing the air change rate in TC (from 0.5 to 7.9 h−1) and PAM (from 0.5 to 14.5 h−1) resulted in a significant 25.1 % and 146.6 % increase in shoot dry mass, respectively. The number of axillary buds per plant exhibited a linear increase response to increasing air change rates only under PAM; as well as a significant difference between PAM (11.5) and TC (8.3) under an air change rate of 7.9 h−1. Particularly advantageous for PAM was simultaneous root growth, escalating from 5.2 to 44.3 mg as the air change rate rose from 0.5 to 14.5 h−1. Implementing the photoautotrophic culture practice not only accelerated Cannabis micropropagation but also maintained outcomes comparable to traditional sugar-based tissue culture, contributing to cost-effective cultivation practices in the Cannabis and tissue culture industries.

Physiological and genetic responses of the benthic dinoflagellate Prorocentrum lima to polystyrene microplastics

Microplastics are well known as contaminants in marine environments. With the development of biofilms, most microplastics will eventually sink and deposit in benthic environment. However, little research has been done on benthic toxic dinoflagellates, and the effects of microplastics on benthic dinoflagellates are unknown. Prorocentrum lima is a cosmopolitan toxic benthic dinoflagellate, which can produce a range of polyether metabolites, such as diarrhetic shellfish poisoning (DSP) toxins. In order to explore the impact of microplastics on marine benthic dinoflagellates, in this paper, we studied the effects of polystyrene (PS) on the growth and toxin production of P. lima. The molecular response of P. lima to microplastic stress was analyzed by transcriptomics. We selected 100 nm, 10 μm and 100 μm PS, and set three concentrations of 1 mg L−1, 10 mg L−1 and 100 mg L−1. The results showed that PS exposure had limited effects on cell growth, but increased the OA and extracellular polysaccharide content at high concentrations. After exposure to PS MPs, genes associated with DSP toxins synthesis, carbohydrate synthesis and energy metabolism, such as glycolysis, TCA cycle and pyruvate metabolism, were significantly up-regulated. We speculated that after exposure to microplastics, P. lima may increase the synthesis of DSP toxins and extracellular polysaccharides, improve the level of energy metabolism and gene expression of ABC transporter, thereby protecting algal cells from damage. Our findings provide new insights into the effects of microplastics on toxic benthic dinoflagellates.

HPLC-Based Automated Synthesis and Purification of Carbohydrates.

Reported herein is a new HPLC-based automated synthesizer (HPLC-A) capable of a temperature-controlled synthesis and purification of carbohydrates. The developed platform allows to perform various protecting group manipulations as well as the synthesis of O- and N-glycosides. A fully automated synthesis and purification was showcased in application to different carbohydrate derivatives including glycosides, oligosaccharides, glycopeptides, glycolipids, and nucleosides.

Asymmetric Pd/Organoboron-Catalyzed Site-Selective Carbohydrate Functionalization with Alkoxyallenes Involving Noncovalent Stereocontrol.

Herein, we demonstrate the robustness of a synergistic chiral Pd/organoboron system in tackling a challenging suite of site-, regio-, enantio- and diastereoselectivity issues across a considerable palette of biologically relevant carbohydrate polyols, when prochiral alkoxyallenes were employed as electrophiles. In view of the burgeoning role of noncovalent interactions (NCIs) in stereoselective carbohydrate synthesis, our mechanistic experiments and DFT modeling of the reaction path unexpectedly revealed that NCIs such as hydrogen bonding and CH-π interactions between the resting states of the Pd-π-allyl complex and the borinate saccharide are critically involved in the stereoselectivity control. Our strategy thus illuminates the untapped potential of harnessing NCIs in the context of transition metal catalysis to tackle stereoselectivity challenges in carbohydrate functionalization.

Asymmetric Pd/Organoboron‐Catalyzed Site‐Selective Carbohydrate Functionalization with Alkoxyallenes Involving Noncovalent Stereocontrol

AbstractHerein, we demonstrate the robustness of a synergistic chiral Pd/organoboron system in tackling a challenging suite of site‐, regio‐, enantio‐ and diastereoselectivity issues across a considerable palette of biologically relevant carbohydrate polyols, when prochiral alkoxyallenes were employed as electrophiles. In view of the burgeoning role of noncovalent interactions (NCIs) in stereoselective carbohydrate synthesis, our mechanistic experiments and DFT modeling of the reaction path unexpectedly revealed that NCIs such as hydrogen bonding and CH‐π interactions between the resting states of the Pd‐π‐allyl complex and the borinate saccharide are critically involved in the stereoselectivity control. Our strategy thus illuminates the untapped potential of harnessing NCIs in the context of transition metal catalysis to tackle stereoselectivity challenges in carbohydrate functionalization.

Enzymatic synthesis of Artemisia capillaris-derived prebiotic oligosaccharide using Leuconostoc mesenteroides MKSR dextransucrase and its potential health functional effects

This study focuses on the enzymatic synthesis of prebiotic oligosaccharide from Artemisia capillaris (AC) using Leuconostoc mesenteroides MKSR dextransucrase and explores their antidiabetic, antidementia, and antioxidant effects through in vitro experiments. A Box-Behnken design was used to optimize transglycosylation conditions to produce Artemisia capillaris-derived oligosaccharide (ACOD) containing isomaltooligosaccahrides (IMO), dextran, and A. capillaris-derived substances with high α-glucosidase inhibition (AGI). The optimized conditions were 3.62 brix of AC, 182.54 mM sucrose, and 11.304 mM maltose. ACOD completely inhibited α-glucosidase activity, with 1.52-fold increase compared to other samples, such as OD (IMO and dextran, transglycosylated by dextransucrase without AC) and AC + OD (a simple mixture of AC and OD). Additionally, ACOD showed noteworthy acetylcholinesterase (103.91%) and butyrylcholinesterase (103.30%) inhibitory activity and potent antioxidant properties in terms of DPPH radical scavenging activity (70.04%), reducing power (100%), and ferric reducing antioxidant power (FRAP). ACOD (3.60) showed a higher prebiotic index compared with AC (-23.11), OD (-2.27), and AC + OD (-9.12). In conclusion, ACOD offers enhanced multi-biological activities as a potential health-functional prebiotic. These findings hold promise for applications in functional foods and pharmaceuticals, expanding our understanding of prebiotic functionality.

Production of recombinant glycosidases fused with Usp45 and SpaX to avoid the purification and immobilization stages

The elucidation of the physicochemical properties of glycosidases is essential for their subsequent technological application, which may include saccharide hydrolysis processes and oligosaccharide synthesis. As the application of cloning, purification and enzymatic immobilization methods can be time consuming and require a heavy financial investment, this study has validated the recombinant production of the set of Lacticaseibacillus rhamnosus fucosidases fused with Usp45 and SpaX anchored to the cell wall of Lacticaseibacillus cremoris subsp cremoris MG1363, with the aim of avoiding the purification and stabilization steps. The cell debris harboring the anchored AlfA, AlfB and AlfC fucosidases showed activity against p-nitrophenyl α-L-fucopyranoside of 6.11 ± 0.36, 5.81 ± 0.29 and 9.90 ± 0.58 U/mL, respectively, and exhibited better thermal stability at 50 °C than the same enzymes in their soluble state. Furthermore, the anchored AlfC fucosidase transfucosylated different acceptor sugars, achieving fucose equivalent concentrations of 0.94 ± 0.09 mg/mL, 4.11 ± 0.21 mg/mL, and 4.08 ± 0.15 mg/mL of fucosylgalatose, fucosylglucose and fucosylsucrose, respectively.

Revolutionizing Renewable Resources: Cutting-Edge Trends and Future Prospects in the Valorization of Oligosaccharides

Lignocellulosic wastes, primarily from agricultural by-products, are a renewable resource increasingly used in the sustainable production of oligosaccharides, significantly contributing to the growing bioeconomy. This innovative utilization of biological resources aligns with the global shift towards sustainable development, focusing on creating products such as food, feed, and bioenergy from renewable sources. Oligosaccharides, specialized carbohydrates, are synthesized either chemically or more eco-friendly, biologically. Biological synthesis often involves enzymes or whole-cell systems to transform lignocellulosic wastes into these valuable sugars. As functional food supplements, oligosaccharides play a crucial role in human and animal health. They serve as prebiotics, indigestible components that promote the proliferation of beneficial gut microbiota, especially within the colon. This positive impact on gut flora is essential for boosting the immune system and regulating physiological functions. Important prebiotics, including galactooligosaccharides (GOS), xylooligosaccharides (XOS), fructooligosaccharides (FOS), mannan-oligosaccharides (MOS), and isomaltooligosaccharides (IMOS), are produced through methods involving enzymes or the use of whole cells, with agricultural waste as substrates. Recent advancements focus on refining these biological processes for oligosaccharide synthesis using lignocellulosic substrates, emphasizing the principles of a circular bioeconomy, which promotes resource reuse and recycling. This review highlights the potential and challenges in the biological synthesis of oligosaccharides from renewable resources. It underscores the need for innovation in process optimization and commercialization strategies to fully exploit lignocellulosic wastes. This approach not only contributes to sustainable product development, but also opens new avenues for the profitable and environmentally friendly utilization of agricultural residues, marking a significant step forward in the bio-based industry.

Organocatalyzed Stereoselective Glycosylation: An Overview of the Last Decade

Abstract: Even though there has been an important evolution in the synthesis of oligosaccharides, the efficient and stereoselective study of glycosidic bonds through non-toxic, moderate, and inexpensive techniques is one of the most challenging fields in organic synthesis. Glycosyl reactions play a fundamental role in biological material and structure-activity relationships, having numerous medicinal chemistry applications. For this, interesting strategies have evolved over the years to control the stereoselectivity of glycosidic bonds, including the manipulation of different reaction elements, mainly promoters or catalysts, but also involving the nature of donors and solvents. This review looks at glycosylation methodologies in the last decade resulting in the specific formation of alpha or beta glycosidic bonds.

MdCIbHLH1 modulates sugar metabolism and accumulation in apple fruits by coordinating carbohydrate synthesis and allocation

The content of soluble sugars is a vital parameter that indicates the quality of fleshy fruits such as apple (Malus domestica Borkh.). Studying the patterns of accumulation of soluble sugars and regulatory mechanisms associated with fruit development is crucial for breeding improved fruit varieties. Here, we report that MdCIbHLH1, a low temperature-induced bHLH transcription factor, inhibits the accumulation of soluble sugars by regulating sugar-metabolizing enzyme activities, photosynthetic performance, and the expression of sugar-related genes in developing apple fruits. MdCIbHLH1 inhibits MdFBP and MdPEPCK expression, thus blocking the conversion of acids to sugars in apple fruits. We also discovered that MdCIbHLH1 decreases the photosynthetic rate and carbohydrate accumulation in apple leaves. Our results suggest that soluble sugar accumulation in apple fruits is influenced by multiple factors, including metabolic status, photosynthesis, and carbohydrate allocation. MdCIbHLH1 is critically involved in controlling the accumulation of soluble sugars by coordinating carbohydrate synthesis and allocation, thus influencing sugar transport and its metabolism during the development of apple fruits.

Parametric Analysis of Donor Activation for Glycosylation Reactions.

The chemical synthesis of complex oligosaccharides relies on efficient and highly reproducible glycosylation reactions. The outcome of a glycosylation is contingent upon several environmental factors, such as temperature, acidity, the presence of residual moisture, as well as the steric, electronic, and conformational aspects of the reactants. Each glycosylation proceeds rapidly and with a high yield within a rather narrow temperature range. For better control over glycosylations and to ensure fast and reliable reactions, a systematic analysis of 18 glycosyl donors revealed the effect of reagent concentration, water content, protecting groups, and structure of the glycosyl donors on the activation temperature. With these insights, we parametrize the first step of the glycosylation reaction to be executed reliably and efficiently.

Polyhalogenated Carbohydrates: Synthesis and Applications of Sugar Halides from Fluorine to Iodine

AbstractPolyfluorinated carbohydrates have attracted attention in the last decades. This is due to the interesting properties of such organofluorines. What about the other halogens? Since the discovery of sucralose (a trichlorinated disaccharide) more than 50 years ago, only a handful of chlorinated, brominated, or iodinated carbohydrates have been reported. This review focuses on the synthesis of polyhalogenated carbohydrates, including sugar inter‐halides, but excluding polyfluorinated sugars. An overview of the current state of the art of their potential application is also described.

Iodosylbenzene-Promoted Glycosylation with Selenoglycosides: Application in One-Pot Glycosylation.

A novel method for the glycosylation of selenoglycosides activated by iodosylbenzene was developed. The glycosylation reaction conditions were mild, fast, and efficient, with a high tolerance to diverse protecting groups and a wide substrate scope, which is advantageous for synthesizing complex glycosides. In addition, selenoglycosides were shown to be orthogonal to thioglycosides under the promotion of iodosylbenzene. Notably, a high yield of the poorly reactive glucuronidation reaction product was obtained by acetyl-protected selenoglycoside. Finally, the orthogonal one-pot synthesis of β-(1→6) oligoglucans demonstrated the usefulness of this method in oligosaccharide synthesis.

Hypervalent Iodine Compounds in Carbohydrate Chemistry: Glycosylation, Functionalization and Oxidation.

This mini review article provides an overview on the use of hypervalent iodine compounds (HICs) in carbohydrate synthesis, focusing on their chemistry and recent applications. HICs are similar to transition metals in their reactivity but have the added benefit of being environmentally benign, and are therefore commonly used as selective oxidants and eco-friendly reagents in organic synthesis. Herein, we summarize various synthetic uses of hypervalent iodine reagents in reactions such as glycosylation, oxidations, functionalization, and C-C bond-forming reactions. The goal of this review is to illustrate the advantages and versatility of using HICs as an environmentally sustainable alternative to heavy metals in carbohydrate chemistry.

Chemical Synthesis of Δ-4,5 Unsaturated Heparan Sulfate Oligosaccharides for Biomarker Discovery.

A methodology is described that can provide heparan sulfate oligosaccharides having a Δ4,5-double bond, which are needed as analytical standards and biomarkers for mucopolysaccharidoses. It is based on chemical oligosaccharide synthesis followed by modification of the C-4 hydroxyl of the terminal uronic acid moiety as methanesulfonate. This leaving group is stable under conditions used to remove temporary protecting groups, O-sulfation, and hydrogenolysis. Treatment with NaOH results in elimination of the methanesulfonate and formation of a Δ4,5-double bond.

Transcriptome Analysis of Intermittent Light Induced Early Bolting in Flowering Chinese Cabbage.

In flowering Chinese cabbage, early booting is one of the most important characteristics that is linked with quality and production. Through fixed light intensity (280 μmol·m-2·s-1) and fixed intermittent lighting in flowering Chinese cabbage, there was early bolting, bud emergence, and flowering. Moreover, the aboveground fresh weight, blade area, dry weight of blade, and quantification of the leaves in flowering Chinese cabbage were significantly reduced, while the thickness of tillers, tillers height, dry weight of tillers, and tillers weight were significantly increased. The chlorophyll contents and soil-plant analysis and development (SPAD) value decreased in the early stage and increased in the later stage. The nitrate content decreased, while the photosynthetic rate, vitamin C content, soluble sugar content, soluble protein content, phenolic content, and flavonoid content increased, and mineral elements also accumulated. In order to explore the mechanism of intermittent light promoting the early bolting and flowering of '49d' flowering Chinese cabbage, this study analyzed the transcriptional regulation from a global perspective using RNA sequencing. A total of 17,086 differentially expressed genes (DEGs) were obtained and 396 DEGs were selected that were closely related to early bolting. These DEGs were mainly involved in pollen wall assembly and plant circadian rhythm pathways, light action (34 DEGs), hormone biosynthesis and regulation (26 DEGs), development (21 DEGs), and carbohydrate synthesis and transport (6 DEGs). Three hub genes with the highest connectivity were identified through weighted gene co-expression network analysis (WGCNA): BrRVE, BrLHY, and BrRVE1. It is speculated that they may be involved in the intermittent light regulation of early bolting in flowering Chinese cabbage. In conclusion, intermittent light can be used as a useful tool to regulate plant growth structure, increase planting density, enhance photosynthesis, increase mineral accumulation, accelerate growth, and shorten the breeding cycle.