Microwave-assisted extraction of mucilage from juá: Characterization and antioxidant activity.

Microwave-assisted extraction of mucilage from juá was investigated using response surface methodology. The optimal conditions for extraction were a power of 300 W, an extraction time of 240 s, a pH of 8.0, and a water/sample ratio of 1/6, which achieved a 26.43% yield. The monosaccharide composition and antioxidant activity of the mucilage from juá fruits from different regions of Caatinga were investigated. The fruits from Agreste Paraibano showed the highest mucilage extraction yield (18.64%) compared to that of fruits from Mata Paraibana (MP) (12.37%), Borborema (BB) (11.47%), and Sertão Paraibano (8.31%) (p < 0.05). Glucose (32.8%-50.8%) and arabinose (19.3%-32.9%) were the main monosaccharides found in juá mucilage. The mucilage from fruits in the MP presented the highest antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl and oxygen radical absorbance capacity assays. Our results demonstrated the potential for the future exploration and application of juá mucilage in the food industry. PRACTICAL APPLICATION: Juá (Ziziphus joazeiro Mart.) mucilage contains phenolic compounds and antioxidant activity, and its extraction by MAE is efficient, as it contributed to a higher yield.

Evaluation of mango residues to produce hyaluronic acid by Streptococcus zooepidemicus.

Mango processing generates significant amounts of residues (35-65%) that may represent environmental problems owed to improper disposal. The use of mango byproducts as substrates to produce hyaluronic acid (HA) is an attractive alternative to reduce the cost of substrate. In this study, we evaluated the potential of hydrolyzates from mango peels and seeds to produce HA by Streptococcus equi. subsp. zooepidemicus. The physicochemical characterization of mango residues showed that the seeds contain a higher amount of holocellulose (cellulose and hemicellulose), which amounts 54.2% (w/w) whereas it only represents 15.5% (w/w) in the peels. Mango peels, however, are composed mainly of hot water-extractives (62% w/w, that include sucrose, fructose, glucose and organic acids). A higher concentration of monosaccharides (39.8 g/L) was obtained from the enzymatic hydrolysis (with Macerex) of peels as compared to seeds (24.8 g/L with Celuzyme). From mango peels, hydrolyzates were obtained 0.6 g/L HA, while 0.9 g/L HA were obtained with hydrolyzates from mango seeds. These results demonstrate that mango byproducts have the potential to be used for production of HA.

Discovery, structural characterization, and functional insights into a novel apiosidase from the GH140 family, isolated from a lignocellulolytic-enriched mangrove microbial community.

OBJECTIVES: Apiosidases are enzymes that cleave the glycosidic bond between the monosaccharides linked to apiose, a branched chain furanose found in the cell walls of vascular plants and aquatic monocots. There is biotechnological interest in this enzyme group because apiose is the flavor-active compound of grapes, fruit juice, and wine, and the monosaccharide is found to be a plant secondary metabolite with pharmaceutical properties. However, functional and structural studies of this enzyme family are scarce. Recently, a glycoside hydrolase family member GH140 was isolated from Bacteroides thetaiotaomicron and identified as an endo-apiosidase. RESULTS: The structural characterization and functional identification of a second GH140 family enzyme, termed MmApi, discovered through mangrove soil metagenomic approach, are described. Among the various substrates tested, MmApi exhibited activity on an apiose-containing oligosaccharide derived from the pectic polysaccharide rhamnogalacturonan-II. While the crystallographic model of MmApi was similar to the endo-apiosidase from Bacteroides thetaiotaomicron, differences in the shape of the binding sites indicated that MmApi could cleave apioses within oligosaccharides of different compositions. CONCLUSION: This enzyme represents a novel tool for researchers interested in studying the physiology and structure of plant cell walls and developing biocatalytic strategies for drug and flavor production.

Polysaccharides from exudate gums of plants and interactions with the intestinal microbiota: A review of vegetal biopolymers and prediction of their prebiotic potential.

Polysaccharides in plant-exuded gums are complex biopolymers consisting of a wide range of structural variability (linkages, monosaccharide composition, substituents, conformation, chain length and branching). The structural features of polysaccharides confer the ability to be exploited in different industrial sectors and applications involving biological systems. Moreover, these characteristics are attributed to a direct relationship in the process of polysaccharide enzymatic degradation by the fermentative action in the gut microbiota, through intrinsic interactions connecting bacterial metabolism and the production of various metabolites that are associated with regulatory effects on the host homeostasis system. Molecular docking analysis between bacterial target proteins and arabinogalactan-type polysaccharide obtained from gum arabic allowed the identification of intermolecular interactions provided bacterial enzymatic mechanism for the degradation of several arabinogalactan monosaccharide chains, as a model for the study and prediction of potential fermentable polysaccharide. This review discusses the main structural characteristics of polysaccharides from exudate gums of plants and their interactions with the intestinal microbiota.

Simultaneous enzyme production, Levan-type FOS synthesis and sugar by-products elimination using a recombinant Pichia pastoris strain expressing a levansucrase-endolevanase fusion enzyme.

BACKGROUND: Although Levan-type fructooligosaccharides (L-FOS) have been shown to exhibit prebiotic properties, no efficient methods for their large-scale production have been proposed. One alternative relies on the simultaneous levan synthesis from sucrose, followed by endolevanase hydrolysis. For this purpose, several options have been described, particularly through the synthesis of the corresponding enzymes in recombinant Escherichia coli. Major drawbacks still consist in the requirement of GRAS microorganisms for enzyme production, but mainly, the elimination of glucose and fructose, the reaction by-products. RESULTS: The expression of a fusion enzyme between Bacillus licheniformis endolevanase (LevB1) and B. subtilis levansucrase (SacB) in Pichia pastoris cultures, coupled with the simultaneous synthesis of L-FOS from sucrose and the elimination of the residual monosaccharides, in a single one-pot process was developed. The proof of concept at 250 mL flask-level, resulted in 8.62 g of monosaccharide-free L-FOS and 12.83 gDCW of biomass, after 3 successive sucrose additions (30 g in total), that is a 28.7% yield (w L-FOS/w sucrose) over a period of 288 h. At a 1.5 L bioreactor-level, growth considerably increased and, after 59 h and two sucrose additions, 72.9 g of monosaccharide-free L-FOS and 22.77 gDCW of biomass were obtained from a total of 160 g of sucrose fed, corresponding to a 45.5% yield (w L-FOS/w sucrose), 1.6 higher than the flask system. The L-FOS obtained at flask-level had a DP lower than 20 fructose units, while at bioreactor-level smaller oligosaccharides were obtained, with a DP lower than 10, as a consequence of the lower endolevanase activity in the flask-level. CONCLUSION: We demonstrate here in a novel system, that P. pastoris cultures can simultaneously be used as comprehensive system to produce the enzyme and the enzymatic L-FOS synthesis with growth sustained by sucrose by-products. This system may be now the center of an optimization strategy for an efficient production of glucose and fructose free L-FOS, to make them available for their application as prebiotics. Besides, P. pastoris biomass also constitutes an interesting source of unicellular protein.

Papiliotrema laurentii: general features and biotechnological applications.

Papiliotrema laurentii, previously classified as Cryptococcus laurentii, is an oleaginous yeast that has been isolated from soil, plants, and agricultural and industrial residues. This variety of habitats reflects the diversity of carbon sources that it can metabolize, including monosaccharides, oligosaccharides, glycerol, organic acids, and oils. Compared to other oleaginous yeasts, such as Yarrowia lipolytica and Rhodotorula toruloides, there is little information regarding its genetic and physiological characteristics. From a biotechnological point of view, P. laurentii can produce surfactants, enzymes, and high concentrations of lipids, which can be used as feedstock for fatty acid-derived products. Moreover, it can be applied for the biocontrol of phytopathogenic fungi, contributing to quality maintenance in post- and pre-harvest fruits. It can also improve mycorrhizal colonization, nitrogen nutrition, and plant growth. P. laurentii is also capable of degrading polyester and diesel derivatives and acting in the bioremediation of heavy metals. In this review, we present the current knowledge about the basic and applied aspects of P. laurentii, underscoring its biotechnological potential and future perspectives. KEY POINTS: • The physiological characteristics of P. laurentii confer a wide range of biotechnological applications. • The regulation of the acetyl-CoA carboxylase in P. laurentii is different from most other oleaginous yeasts. • The GEM is a valuable tool to guide the construction of engineered P. laurentii strains with improved features for bio-based products.

Sensitivity and specificity of body mass index and main risk factors for cardiovascular disease in middle-income urban participants in Guanajuato, Mexico.

Introduction: Introduction: several studies have questioned body mass index (BMI) as an accurate diagnostic tool for obesity and therefore a predictor of cardiovascular risk. But BMI is widely used currently. Objective: we analyzed the sensitivity and specificity of BMI and compared cardiovascular risk factors in middle-income urban participants in Guanajuato, Mexico, at different ages. Design: an analytical and cross-sectional study was carried out in 385 apparently healthy subjects, stratified by age ranges (20 to 59 years old). A high global CVD risk was obtained with the Framingham risk score (Framingham Risk Score > 20 %). The odds ratio was used to assess the association between high global CVD risk and the dietetic and anthropometric variables. Sensitivity, specificity, and correlation statistical analyses were carried out between BMI and other anthropometric variables with high cardiovascular risk, and this was integrated to derive recommendations to improve risk factor detection (p < 0.05 and power of 80 %). Results: a high global CVD risk was found in 4 % of the sample. BMI ≥ 30 kg/m2 had a sensitivity of 77 % for the detection of high cardiovascular risk; waist circumference ≥ 90 cm (men) or ≥ 80 cm (women) and body fat percentage ≥ 2 5% (men) or ≥ 35 % (women) had a sensitivity of 100 %. BMI showed a significant association with high global CVD risk (OR = 6.1; 95 % CI, 1.6-22.6, p < 0.01), but was not able to predict high global CVD risk in at least 30 % of the cases. There was not significative difference by age group for waist circumference, body fat percentage, total cholesterol, and low-density lipoprotein. Regarding the comparison of dietary intake of the stratified population by age group, intake of cholesterol, added sugars, fiber, sodium were highest in the 20 years group. Conclusions: a higher intake of cholesterol, simple sugars, and sodium was observed in the 20-year-old age group. The use of BMI with waist circumference and percentage of body fat used together allow a better assessment of cardiovascular risk. We need to integrate this new recommendation to increase early detection of main risk factors for cardiovascular disease.

Introducción: Introducción: diversos estudios han cuestionado el índice de masa corporal (IMC) como herramienta diagnóstica certera de la obesidad y por tanto predictor de riesgo cardiovascular. Pero el IMC es ampliamente utilizado actualmente. Objetivo: se analizó la sensibilidad y especificidad del IMC y se compararon factores de riesgo cardiovascular en participantes de diferentes edades de zonas urbanas de ingresos medios en Guanajuato, México. Diseño: se realizó un estudio analítico y transversal en 385 participantes, aparentemente sanos, estratificados por rangos de edad (20 a 59 años). El riesgo de CVD global alto se obtuvo con la puntuación de riesgo de Framingham (puntuación de riesgo de Framingham > 20 %). Se calculó la odds ratio para evaluar la asociación entre el alto riesgo global de ECV y las variables dietéticas y antropométricas. Se realizó un análisis estadístico de sensibilidad, especificidad y correlación entre el IMC y otras variables antropométricas con el alto riesgo cardiovascular, y se integró para derivar recomendaciones para mejorar la detección de factores de riesgo (p < 0,05 y potencia del 80 %). Resultados: se encontró un alto riesgo global de ECV en el 4 % de la muestra. El IMC ≥ 30 kg/m2 tuvo una sensibilidad del 77 % para la detección del alto riesgo cardiovascular; la circunferencia de la cintura ≥ 90 cm (hombre) o ≥ 80 cm (mujer) y el porcentaje de grasa corporal ≥ 25 % (hombre) o ≥ 35 % (mujer) tuvo una sensibilidad del 100 %. El IMC mostró una asociación significativa con un alto riesgo global de ECV (OR = 6,1; IC 95 % 1,6-22,6; p < 0,01) pero no fue capaz de predecir un alto riesgo global de ECV en al menos el 30 % de los casos. No hubo diferencia significativa por grupo de edad para circunferencia de cintura, porcentaje de grasa corporal, colesterol total y lipoproteínas de baja densidad. Con respecto a la comparación de la ingesta dietética de la población estratificada por grupos de edad, la ingesta de colesterol, azúcares añadidos y sodio fue mayor en el grupo de 20 años. Conclusiones: se observó una mayor ingesta de colesterol, azúcares simples y sodio en el grupo de edad de 20 años. El uso del IMC con la circunferencia de la cintura y el porcentaje de grasa corporal utilizados conjuntamente permiten lograr una mejor evaluación del riesgo cardiovascular. Necesitamos contar con herramientas para aumentar la detección temprana de los principales factores de riesgo de enfermedad cardiovascular.

Acid Hydrolysis of Pectin and Mucilage from Cactus (Opuntia ficus) for Identification and Quantification of Monosaccharides.

Pectin and mucilage are polysaccharides from the cactus Opuntia ficus-indica, which are also known as hydrocolloids, with useful properties in industries such as food, pharmaceuticals, and construction, among others. In the present work, cactus hydrocolloids were hydrolyzed characterized using two techniques: first, thin-layer chromatography, to identify the monosaccharides present in the sample, followed by the phenol-sulfuric acid method to determine the monosaccharide content. The hydrolyzing method allowed us to reduce the processing time to 180 min and, considering the identification and quantification procedures, the proposed methodology is much simpler and more cost-effective compared to other methods, such as high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), and mass spectrometry. The analysis of the results revealed that the maximum concentration of monosaccharides was obtained after hydrolyzing for 90 min. Under such conditions, with pectin being the main component contained in the cactus hydrocolloids analyzed here, galacturonic acid was found in the largest quantities.

Isolation, characterisation and complement fixation activity of acidic polysaccharides from Argemone mexicana used as antimalarials in Mali.

CONTEXT: Global studies on Argemone mexicana L. (Papaveraceae) traditionally used against malaria in Mali are limited to its low-mass compounds activities, and little information on its bioactive polysaccharides is available. OBJECTIVE: This study determines the structure and the immunomodulatory activity of polysaccharides from aerial parts of A. mexicana. MATERIALS AND METHODS: Acidic polysaccharides from this plant material named HMAmA1 and HMAmA2 were isolated from water extracts. Their monosaccharide composition was determined by gas chromatography. Glycosidic linkages were determined using GC-MS. NMR was also applied. The polymers were tested for effects on the human complement system in vitro at different doses. RESULTS: The monosaccharide composition showed that the two polysaccharides contained in different amounts the following monomers: arabinose, rhamnose, galactose, and galacturonic acid. Overall structural analysis showed the presence of a low ratio of 1,2-linked rhamnose compared to 1,4-linked galacturonic acid with arabinogalactans substituted on position 4 of rhamnose. NMR data showed the presence of galacturonans alternated by rhamnogalacturonans bearing arabinose and galactose units. α-Linkages were found for l-arabinose, l-rhamnose and d-galacturonic acid, while ß-linkages were found for d-galactose. The two polysaccharides exhibited strong complement fixation activities, with HMAmA1 being the highest potent fraction. ICH50 value of HMAmA1 was 5 µg/mL, compared to the control BPII being 15.9 µg/mL. DISCUSSION AND CONCLUSIONS: Polysaccharides form A. mexicana presented a complement fixation effect. The complement system is an important part of the immune defense, and compounds acting on the cascade are of interest. Therefore, these polymers may be useful as immunodulatory agents.

Metabolomic Profiling of Phloem Sap from Different Pine Species and Implications on Black Capuchin.

In most commercial pine farms in southern Brazil, black capuchin causes damage to wood and financial losses when it removes bark from some pine species to feed upon underlying vascular tissues. Therefore, this study aimed to evaluate the variability of the primary metabolites of phloem saps from 10 different species of pine by NMR spectroscopy, as well as the aroma compounds using SPME-GC-MS. Each technique provided a different set of metabolites that we can correlate to monkey predilection. The PCA showed monosaccharide (detected by NMR) and α-pinene (pine-like and resinous flavor descriptors) as attractive compounds for monkeys. On the other hand, the low content of monosaccharide and the high content of ß-phellandrene (citrus odor descriptor) was observed in less attacked pine species (P. patula). The data fusion on primary metabolites and aroma compounds corroborated the individual analyses, complementing the comprehension of the monkey predilection. Thus, P. elliottii was an avoided tree even with high content of sugars possibly due to its high content of ß-phellandrene (citrus odor). The results are useful for further behavioral studies to determine the role that each highlighted metabolite plays in chemically mediated animal-plant interactions.

Hyperglycemia alters N-glycans on colon cancer cells through increased production of activated monosaccharides.

Diabetes Mellitus (DM) is both, correlated and a known risk factor for colorectal cancer (CRC). Besides favoring the incidence of CRC, DM also accelerates its progression, worsening its prognosis. Previously, hyperglycemia, the DM hallmark, has been shown to lead to aberrant glycosylation of CRC cells, heightening their malignancy both in vivo and in vitro. Here we use mass spectrometry to elucidate the composition and putative structures of N-glycans expressed by MC38 cultured in normoglycemic (LG) and hyperglycemic-like conditions (HG). N-glycans, 67, were identified in MC38 cells cultured in LG and HG. The cells grown in HG showed a greater abundance of N-glycans when compared to LNG cells, without changes in the proportion of sialylated, fucosylated and mannosylated N-glycans. Among the identified N-glycans, 16 were differentially expressed, mostly mannosylated and fucosylated, with a minority of them being sialylated. Metabolomics analysis indicates that the alterations observed in the N-glycosylation may be mostly due to increase of the activated monosaccharides pool, through an increased glucose entrance into the cells. The alterations found here corroborate data from the literature regarding the progression of CRC, advocating for development or repositioning of effective treatments against CRC in diabetic patients.

Influence of sugar consumption from foods with different degrees of processing on anthropometric indicators of children and adolescents after 18 months of follow-up.

Excessive consumption of ultra-processed foods is associated with the development of metabolic changes in children and adolescents. However, the consumption of total sugars, monosaccharides and disaccharides present in these ultra-processed foods and other food groups and its association with anthropometric indicators must be evaluated. Therefore, this study aimed at analysing the influence of sugar consumption from foods with different degrees of processing on anthropometric indicators of children and adolescents after 18 months of follow-up. This cohort study was conducted among 492 children and adolescents aged 7-15 years. Information on food consumption and anthropometry was collected during three follow-up stages. NOVA classification was used for food categorisation. The influence of sugar consumption on the variation of anthropometric measurements over time was evaluated using generalised estimation equation models. During the analysis period, for each increase of 1 g/d in the consumption of total sugars and monosaccharides from ultra-processed foods, there was an increase of 0·002 kg/m2 (P = 0·030) and 0·001 kg/m2 (P = 0·019) in BMI/Age; increase of 0·073 (P < 0·001), 0·032 (P < 0·001) and 0·100 (P < 0·001) in the BMI/Age z-score; and increase of 0·001 cm (P = 0·001), 0·001 cm (P = 0·003) and 0·003 cm (P < 0·001) in waist circumference, with the consumption of total sugars, monosaccharides and disaccharides, respectively. Our study findings support the evidence that the consumption of total sugars, monosaccharides and disaccharides from ultra-processed foods is associated with weight gain and abdominal fat in children and adolescents, which may represent an important risk factor for excess weight in this age group.

Intestinal microbiota fingerprint in subjects with irritable bowel syndrome responders to a low FODMAP diet.

Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disorder characterized by abdominal pain and altered bowel habit. IBS patients report that FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) diet induce or exacerbate their symptoms. It has been reported that low-FODMAP diet (LFD) improves the symptoms in 50%-80% of IBS patients. We aimed to identify IBS responders and non-responders' patients to LFD by determining baseline fecal microbial composition, sequencing the 16S rRNA gene V3-V4 region. Thirty-two participants with IBS were included, 29 women (90.62%) and three men (9.37%), and instructed to follow a four-week LFD, Visual Analogue Scale for IBS was used to assess intervention response. Twenty-two participants were responders (68.75%), and ten were non-responders (31.25%). Differential abundance analysis of Amplicon Sequence Variant (ASVs), before LFD, identified Prevotella 9 and Veillonella genus in responder group, and Barnesiella, Paraprevotella, Bifidobacterium and Ruminococcus 1 genus in non-responder group. After LFD, differentially abundant ASVs were only identified in R, belonging to Veilonella, Butyrivibrio, and 5 ASVs belonging to Ruminiclostridium 6 genus. Linear Discriminant Analysis (LDA), was used to classify patients by responsiveness, considering baseline abundance of 5 bacterial genera, LDA accuracy model was 96.87%, correctly classifying 95.45% of in responder group and 100% and non-responder group. In conclusion, bacterial biomarkers are useful to classify IBS individuals by responsiveness to LFD.

The potential of extracellular biopolymer production by Mesorhizobium sp. from monosaccharide constituents of lignocellulosic biomass.

OBJECTIVE: The effects of monosaccharide constituents of lignocellulosic materials on exopolysaccharide (EPS) production by Mesorhizobium sp. Semia 816 were studied. RESULTS: According to the results, by using sugars commonly found in lignocellulosic biomass as carbon sources (glucose, arabinose and xylose), no significant differences were observed in the production of EPS, reaching 3.39 g/L, 3.33 g/L and 3.27 g/L, respectively. Differences were observed in monosaccharide composition, mainly in relation to rhamnose and glucuronic acid contents (1.8 times higher when arabinose was compared with xylose). However, the biopolymers showed no differences in relation to rheological properties, with EPS aqueous-based suspensions (1.0% w/v) presenting pseudoplastic behavior, and a slight difference in degradation temperatures. Using soybean hulls hydrolysate as carbon source, slightly higher values were obtained (3.93 g/L). CONCLUSION: The results indicate the potential of the use of lignocellulosic hydrolysates containing these sugars as a source of carbon in the cultivation of Mesorhizobium sp. Semia 816 for the production of EPS with potential industrial applications.

Recovery of Anthocyanins and Monosaccharides from Grape Marc Extract by Nanofiltration Membranes.

Wastewaters and by-products generated in the winemaking process are important and inexpensive sources of value-added compounds that can be potentially reused for the development of new products of commercial interest (i.e., functional foods). This research was undertaken in order to evaluate the potential of nanofiltration (NF) membranes in the recovery of anthocyanins and monosaccharides from a clarified Carménère grape marc obtained through a combination of ultrasound-assisted extraction and microfiltration. Three different flat-sheet nanofiltration (NF) membranes, covering the range of molecular weight cut-off (MWCO) from 150 to 800 Da, were evaluated for their productivity as well as for their rejection towards anthocyanins (malvidin-3-O-glucoside, malvidin 3-(acetyl)-glucoside, and malvidin 3-(coumaroyl)-glucoside) and sugars (glucose and fructose) in selected operating conditions. The selected membranes showed differences in their performance in terms of permeate flux and rejection of target compounds. The NFX membrane, with the lowest MWCO (150-300 Da), showed a lower flux decay in comparison to the other investigated membranes. All the membranes showed rejection higher than 99.42% for the quantified anthocyanins. Regarding sugars rejection, the NFX membrane showed the highest rejection for glucose and fructose (100 and 92.60%, respectively), whereas the NFW membrane (MWCO 300-500 Da) was the one with the lowest rejection for these compounds (80.57 and 71.62%, respectively). As a general trend, the tested membranes did not show a preferential rejection of anthocyanins over sugars. Therefore, all tested membranes were suitable for concentration purposes.

A novel mechanism of ß-glucosidase stimulation through a monosaccharide binding-induced conformational change.

It is urgent the transition from a fossil fuel-based economy to a sustainable bioeconomy based on bioconversion technologies using renewable plant biomass feedstocks to produce high chemicals, bioplastics, and biofuels. ß-Glucosidases are key enzymes responsible for degrading the plant cell wall polymers, as they cleave glucan-based oligo- and polysaccharides to generate glucose. Monosaccharide-tolerant or -stimulated ß-glucosidases have been reported in the past decade. Here, we describe a novel mechanism of ß-glucosidase stimulation by glucose and xylose. The glycoside hydrolase 1 family ß-glucosidase from Thermotoga petrophila (TpBgl1) displays a typical glucose stimulation mechanism based on an increased Vmax and decreased Km in response to glucose. Through molecular docking and dynamics analyses, we mapped putative monosaccharide binding regions (BRs) on the surface of TpBgl1. Our results indicate that after interaction with glucose or xylose at BR1 site, an adjacent loop region assumes an extended conformation, which increases the entrance to the TpBgl1 active site, improving product formation. Biochemical assays with TpBgl1 BR1 mutants, TpBgl1D49A/Y410A and TpBgl1D49K/Y410H, resulted in decreasing and abolishing monosaccharide stimulation, respectively. These mutations also impaired the BR1 looping extension responsible for monosaccharide stimulation. This study provides a molecular basis for the rational design of ß-glucosidases for biotechnological applications.

Molecular α-relaxation process of exopolysaccharides extracted from Nostoc commune cyanobacteria.

Broadband dielectric spectroscopy was used to investigate the molecular α-relaxation of the exopolysaccharides (EPS) extracted from Nostoc commune cyanobacteria. The EPS were modified in different ways. EPS were carboxymethylated to obtain carboxymethyl-exopolysaccharides (CEPS). EPS and CEPS were doped with ammonium iodide and 1-butyl-3-methylimidazolium chloride. An α relaxation process was observed for all specimens. The temperature dependence of the relaxation times for pure and doped, EPS and CEPS polymers exhibited non-Arrhenius behavior. This relaxation process was associated with the glass transition of the complex heteropolysaccharides produced by the cyanobacteria. The molecular mobility at the glass transition, Tg, was affected by both the carboxymethylation treatment and the doping. The fragility index also decreased for the doped specimens, which may be attributed to an increase in the mobility of the polymer chains due to the plasticizing effect of the doping agents.

Extraction and characterization of a pectin from coffee (Coffea arabica L.) pulp with gelling properties.

About 0.5 ton of coffee pulp is generated for each ton of coffee cherry processed. In the present study, this waste was investigated as a source of pectin. Coffea arabica L. pulp was dried, treated with ethanol and the pectin extracted with 0.1 M HNO3 (14.6 % yield). Chromatographic, colorimetric and spectroscopic methods were used for pectin characterization. It had 79.5 % galacturonic acid, high methoxyl content (63.2 %), low levels of acetylation, protein and phenolics and Mw of 3.921 × 105 g/mol. The pectin from coffee pulp was able to form gels with high concentration of sucrose or xylitol and low pH. The effect of pH (1.5-3.0), concentrations of pectin (0.5-2.5 %), sucrose (55-65 %) and xylitol (55-60 %) on the viscoelastic properties was investigated. Gels prepared with xylitol diplayed similar viscoelastic behavior to the gels prepared with sucrose. The results demonstrated that coffee pulp is a potential source of commercial pectin with gelling properties.

Screening and structure study of active components of Astragalus polysaccharide for injection based on different molecular weights.

As a special traditional Chinese medicine, Astragalus polysaccharides for injection (APS, batch no. Zhunzi Z20040086) includes complex polysaccharide macromolecules that may increase the risk upon application. Although fingerprints for quality control are available, the specific active ingredients are unclear. Identifying the active components is the key to reduce the risk of adverse reactions of the drug. In this work, APS was mainly separated into two components, namely, macromolecular component (APS-I) and small molecular components (APS-II). The molecular weight measurement revealed that the average molecular weight of APS-I exceeded 500 kDa, and that of APS-II was 10 kDa. Monosaccharide-composition analysis revealed that APS-I consisted of glucose, galactose, arabinose, rhamnose, and galacturonic acid, with a ratio of approximately 1.5:1:5.4:0.08:0.1. Meanwhile, APS-II consisted of glucose, galactose, arabinose, rhamnose, and galacturonic acid, with a molar ratio of 9:1:1.4:0.04:0.001. Methylation, FT-IR, and NMR analysis indicated that the APS-I monosaccharide residue was linked as follows: D-Glcp-(1→, →4)-D-Glcp-(1→, →2)-L-Rhap-(1→, D-Araf-(1→, →5)-D-Araf-(1→, →2,5)-D-Araf-(1→, →4)-D-Galp-(1 â†’ . Meanwhile, the APS-II monosaccharide residue was connected as follows: α-D-Glcp-(1→, →4)-α-D-Glcp-(1→, →6)-α-D-Glcp-(1→, →4,6)-α-D-Glcp-(1→, →3,4,6)-α-D-Glcp-(1→, →2)-α-L-Rhap-(1→, α-D-Araf-(1→, →5)-α-D-Araf-(1→, →4)-ß-D-Galp-(1 â†’ . Screening experiments on their in vitro immunological activity showed that APS-II had stronger effect on innate and adaptive immunities than APS-I. In vivo animal experiments showed that APS-II can increase the leukocyte level of cyclophosphamide immunosuppressed mice and improve their immunomodulatory ability. Therefore, APS-II is the main active ingredient of APS and is expected to become a new generation of APS products.

Is the orofacial antinociceptive effect of lectins intrinsically related to their specificity to monosaccharides?

Lectins are proteins of non-immunological origin that may play several biological applications, of which we can highlight the anti-inflammatory and antinociceptive activities. In this work, we evaluated the possible effect of orofacial antinociceptive activity of three plant lectins, Dioclea violacea (DVL - Man/Glc-binding), Vatairea macrocarpa (VML - Gal-binding) and PPL (Parkia platycephala - Man/Glc-binding) in adult zebrafish. Acute nociception was induced by menthol (1.2 µM), or capsaicin (4.93 µM) applied into in the upper lip (5.0 µL) of adult wild zebrafish. Zebrafish were pretreated by intraperitoneal injection (20 µL) with vehicle (Control) or lectins (0.025; 0.05 or 0.1 mg/mL) 30 min before induction. The effect of lectins on zebrafish locomotor behavior was evaluated with the open field test. Naive groups (n = 8) were included in all tests. Our results indicate that only PPL presented antinociceptive induced by capsaicin, suggesting the potential clinical application of PPL as inhibitor of orofacial nociception and that this effect may be due to the modulation of TRPV1 channel. In conclusion, lectins that exhibit affinity to the same or different carbohydrates do not necessarily have an antinociceptive effect on the orofacial nociception model, indicating that the glycan carbohydrate binding pattern may be related to the effect on nociception inhibition.