Pectins are plant cell-wall polysaccharides which can be utilized by commensal bacteria in the gut, exhibiting beneficial properties for the host. Knowledge of the impact of pectins on intestinal ...bacterial communities is insufficient and limited to a few types of pectins. This study characterized the relationship between the structural properties of pectins and their potential to modulate composition and activity of the gut microbiota in a beneficial way. For this purpose we performed
fermentations of nine structurally diverse pectins from citrus fruits and sugar beet, and a pectic derivative, rhamnogalacturonan I (RGI), using a TIM-2 colon model. The composition of microbiota during TIM-2 fermentations was assessed by 16S rRNA gene amplicon sequencing. Both general and pectin-specific changes were observed in relative abundances of numerous bacterial taxa in a time-dependent way. Bacterial populations associated with human health, such as
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spp. were either increased or decreased depending on the substrate, suggesting that these bacteria can be controlled using structurally different pectins. The main structural features linked to the pectin-mediated shifts in microbiota included degree of esterification, composition of neutral sugars, distribution of homogalacturonan and rhamnogalacturonan fractions, degree of branching, and the presence of amide groups. Cumulative production of the total short chain fatty acids and propionate was largest in fermentations of the high methoxyl pectins. Thus, this study indicates that microbial communities in the gut can be specifically modulated by pectins and identifies the features in pectin molecules linked to microbial alterations. This knowledge can be used to define preferred dietary pectins, targeting beneficial bacteria, and favoring more balanced microbiota communities in the gut.
Pectins are plant polysaccharides used in food industry as gelling and stabilizing agents. This study investigated the ability of pectins to improve survival of probiotic species Lactobacillus ...fermentum PCC, L. reuteri RC-14, L. rhamnosus LGG and L. paracasei F-19 in simulated gastric solution in relationship to their structural and physical properties. Electrostatic interactions between pectins and bacteria were evaluated by the Zeta-potential approach. Bacterial survival was assessed by flow cytometry and plate counting. L. fermentum PCC and L. reuteri RC-14 were more resistant to gastric conditions; their survival rate was further improved in the presence of five out of ten tested pectins. Additionally, two of the pectins had a positive effect on viability of the less resistant L. rhamnosus LGG and L. paracasei F-19. The beneficial effect was generally observed for the high-methoxylated pectins, indicating that substituted polygalacturonic acid in the backbone is essential for bacterial protection. Other pectin features associated with improved survival, included less negative Zeta-potential, higher molecular weight, as well as lower values of hydrodynamic sizes, viscosity and degree of branching. The study indicates that pectins have a potential to protect probiotic bacteria through the gastro-intestinal transit and identifies the features linked to their functionality.
•Viability of Lactobacillus spp. in simulated gastric solution can be improved by pectins.•The effect of pectins on bacterial survival was species-specific.•The protective effect of pectins was linked to their structural and physical properties.•The properties of pectins associated with bacterial survival were defined.
Akkermansia muciniphila, an abundant member of the human gut microbiota, has been suggested as a potential next-generation probiotic. However, its high sensitivity to oxygen limits the development of ...dosage protocols. Here, we describe microencapsulation, in a xanthan and gellan gum matrix, and a subsequent freeze-drying protocol for A. muciniphila DSM22959. For comparison Lactobacillus plantarum subsp. plantarum ATCC14917 was microencapsulated and freeze-dried using similar protocols. Four different mixtures were tested for cryoprotective properties: sucrose 5% plus trehalose 5%; agave syrup 10%; skim milk 10%, glucose 1%, yeast extract 0.5%, and mannitol 2.5%; as well as peptone 0.1% plus sorbitol 1.2%. Milli-Q-water served as control. Only cryoprotectant solutions with high sugar or protein content significantly improved the survival of both strains during freeze-drying. Microencapsulated cells were stored aerobically or anaerobically for 1 month at 4 °C or 25 °C. Survival of A. muciniphila was significantly better when stored anaerobically at 4 °C. The survival of microencapsulated L. plantarum, was relatively stable at both temperatures under anaerobic conditions. Survival of microencapsulated cells was compared with that of free cells during in vitro simulated upper gastrointestinal tract (GIT) transit at fasted and fed state. During in vitro simulated stomach passage, encapsulation significantly improved survival and viable cells remained at relevant levels after the entire simulated upper GIT transit. In conclusion, we here report a protocol for encapsulating A. muciniphila giving acceptable storage stability and enhancing survival during in vitro simulated upper GIT transit and thus constitutes an important step towards enabling future use of this important member of the human colonic microbiota as a probiotic.
Full‐thickness cutaneous trauma, due to the lack of dermis, leads to difficulty in epithelialization by keratinocytes, developing a fibrotic scar, with less elasticity than the original skin, which ...may have disorders in predisposed individuals, resulting in hypertrophic scar and keloids. Biomedical materials have excellent characteristics, such as good biocompatibility and low immunogenicity, which can temporarily replace traditional materials used as primary dressings. In this work, we developed two dermal matrices based on Nile tilapia collagen, with (M_GAG) and without (M) glycosaminoglycans, using a sugarcane polymer membrane as a matrix support. To assess the molecular mechanisms driving wound healing, we performed qualitative proteomic analysis on the wound bed in an in vivo study involving immunocompetent murine models at 14 and 21 days post‐full‐thickness skin injury. Gene Ontology and Pathway analysis revealed that both skins were markedly represented by modulation of the immune system, emphasizing controlling the acute inflammation response at 14 and 21 days post‐injury. Furthermore, both groups showed significant enrichment of pathways related to RNA and protein metabolism, suggesting an increase in protein synthesis required for tissue repair and proper wound closure. Other pathways, such as keratinization and vitamin D3 metabolism, were also enriched in the groups treated with M matrix. Finally, both matrices improved wound healing in a full post‐thick skin lesion. However, our preliminary molecular data reveals that the collagen‐mediated healing matrix lacking glycosaminoglycan (M) exhibited a phenotype more favorable to tissue repair, making it more suitable for use before skin grafts.
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.
Several naturally occurring biopolymers are commercially produced from livestock and farmed animals processing wastes, including aquatic organisms. These wastes are considered valuable coproducts of ...fishery processing industry, from which biopolymers may be recovered and exploited for their bioactive potential. The aim of this work was to prepare polymeric films from collagen and chitosan solutions, extracted from fishery discards, and investigate the cytotoxicity and immunomodulatory activity towards human peripheral blood mononuclear cells (PBMCs). PBMCs were isolated from healthy donors and treated with Chitosan, Collagen, Chitosan+Collagen solutions and Chitosan+Collagen film in order to measure the changes in cell viability, cytosolic calcium concentration (Ca2+cyt), mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS) levels, differentiation and activation of T CD8+ and CD4+ lymphocytes, and cytokine production. Results showed that collagen and chitosan preparations did not show cytotoxic effect, while cellular IL-6, IL-10, and TNF-α release was observed. Chitosan and collagen were able to promote non-cytotoxic PBMCs activation through cytosolic and mitochondrial ROS production. There was a noteworthy phenotyping of lymphocytes T CD8+ and CD4+ counting and an increase of Ca2+ cyt and ΔΨm levels. These results suggest that chitosan/collagen-based biomaterials produce immunostimulatory effects on PBMC with potential to biomedical approaches.
Semen cryopreservation ensures the storage of stallion genetics for an unlimited time. The improvement of extenders with new antioxidant substances can optimize the properties of post-thawed semen. ...The study aimed to investigate the addition effect of medium-molecular-weight carboxymethylchitosan (CQm) derivates to freezing diluent of stallion sperm after freezinf/thawing. Twice a week, five ejaculates of four stallions were obtained, totalizing 20 ejaculates. Semen was diluted in commercial freezing extender (Botucrio) supplemented with CQm: control (0), 0.75, 1.5, and 3 mg/mL. Samples were filled in straws (0.5 mL) and submitted to freezing and storage at -196°C. Thawing was performed at 37°C/30 s, and the samples of each group were analyzed for kinetics, plasma membrane integrity, acrosome membrane integrity, and mitochondrial membrane potential . The addition of 1.5 and 3 mg/mL CQm showed lower values (P < .05) of total motility (TM), progressive motility (PM), curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP) and wobble (WOB), comparing to control group. Besides, it was observed lower (P < .05) percentages of sperm with intact acrosomes in the group treated with 3 mg/mL of CQm than control group. In conclusion, high concentration of medium-molecular-weight carboxymethylchitosan to freezing diluent damages kinematic and acrosome of stallion sperm after freezing/thawing.
•Subsidies for a better understanding of the wide M. carcinus digestive capability during part of its juvenile stage.•Activities of Lipase, amylases, β-galactosidase and agarase were identified in M. ...carcinus juvenile.•Activities of chymotrypsin, eight aminopeptidases and a calcium-resistant trypsin were also identified.•Carbohydrases diversity may contribute to the management of the energy/protein ratio in cultures.•The amylase: protease ratio obtained here suggests a higher necessity for animal protein in diet.
This study assessed the activity of the main digestive enzymes in juveniles of the painted river prawn Macrobrachium carcinus. Prawns reared in 24 m2 tanks at a density of 10 individuals. m−2 for 45 days were fed a commercial diet with 40 % crude protein. A sample of 21 prawns with 2.92 ± 0.60 g and 27.87 ± 1.50 mm had their midgut glands (MG) dissected. Assays prospecting total proteolytic activity, total amylase, α-amylase, trypsin, chymotrypsin, β-galactosidase, agarase and lipase in the MG were performed. The activities of several aminopeptidase (alanine, arginine, glycine, histidine, isoleucine, leucine, proline and tyrosine aminopeptidase) were also evaluated. In addition, the effect of calcium (CaCl2) on trypsin activity was assessed. The following mean (± SD) activities were found: total proteolytic activity (8.00 ± 0.003 U.mg-1); total amylase (0.322 ± 0.002 U.mg-1); α-amylase (8.730 ± 0.008 U.mg-1); trypsin (12.7 ± 0.001 mU.mg-1); chymotrypsin (19.94 ± 0.0019 mU.mg-1); β-galactosidase (59.4 ± 0.18 U.mg-1); agarase (13.34 ± 0.15 U.mg-1) and lipase (0.019 ± 2.73 U.mg-1). Amongst aminopeptidases, only alanine, arginine, glycine and leucine aminopeptidase were found to be active. At concentrations from 5 to 90 mM, the activity of trypsin was not affected by CaCl2. Compared to other prawn species, M. carcinus has a wide range of digestive enzymes and a tendency towards greater use of animal protein. As studies on the digestive enzymes of juvenile prawns of the Macrobrachium genus are scarce, the present results represent basic data that may serve as a reference for future studies and also aid in the formulation of diets specific for this important group of crustaceans.
In order to characterize the affinity between specific carbohydrate-binding proteins such as lectins, a model is proposed to study these interactions using a polysaccharide membrane to simulate such ...adsorption. Here, lectin-carbohydrate interactions were chemiluminescently investigated using lectins conjugated to acridinium ester (AE) and polysaccharides composed of their respective specific carbohydrates. The lectin-AE conjugates were incubated with discs (0.0314–0.6358 cm2) of phytagel, chitosan and carrageenan. The complex formation chemiluminescently detected followed the Langmuir isotherm from which constants were estimated. The association constant (Ka) and maximum binding sites on the membranes were 2.4 × 10−7 M−1 ± 0.8 × 10−7 M−1 and 1.3 × 10−3 mol. mg−1 ± 0.3 × 10−3 mol. mg−1 (Con A); 0.9 × 10−6 M−1 ± 0.4 × 10−6 M−1 and 0.021 × 10−3 mol. mg−1 ± 0.003 × 10−3 mol. mg−1 (WGA) and 2.0 × 10−6 M−1 ± 0.9 × 10−6 M−1 and 0.069 × 10−3 mol. mg−1 ± 0.010 × 10−3 mol. mg−1 (PNA). The proposed model might be useful to study binding affinity and estimate the amount of binding not limited by the sugar content in the membrane.
Background: The consumption of alcoholic drinks is a frequent drug‐abuse situation, which is associated to a wide variety of pathological disturbances affecting several organs, including the brain. ...We have previously shown in the developing rat brain that ethanol intake facilitates the propagation of cortical spreading depression (CSD), an excitability‐related neural phenomenon present in several animal species. This electrophysiological effect was attenuated by a shrimp (Litopenaeus vannamei) carotenoids extract. Here we investigated the effects of pure astaxanthin, the main carotenoid found in shrimp, on CSD.
Methods: Adult Wistar rats were treated per gavage, during 18 days, with 2.5, 10 or 90 μg/kg/d astaxanthin dissolved in ethanol (3 g/kg) and CSD was recorded on the cortical surface 1 to 3 days thereafter. Four groups, treated respectively with ethanol, distilled water and soybean oil with‐ and without astaxanthin were also studied for comparison with the ethanol + astaxanthin groups.
Results: Ethanol‐treated rats displayed higher CSD‐velocities (mean values, in mm/min, per hour of recording ranging from 4.08 ± 0.09 to 4.12 ± 0.16), compared to the distilled water‐group (from 3.19 ± 0.13 to 3.27 ± 0.06). Addition of astaxanthin to ethanol lead to lower CSD‐velocities in a dose‐dependent manner, ranging from 3.68 ± 0.09 to 3.97 ± 0.22 for the 2.5 μg/kg/d‐dose, from 3.29 ± 0.09 to 3.32 ± 0.07 for the 10 μg/kg/d‐dose, and from 2.89 ± 0.13 to 2.92 ± 0.11 for the 90 μg/kg/d‐dose. The velocities of the soybean oil groups (with and without astaxanthin) were not statistically different from the 10 μg/kg/d astaxanthin + ethanol and distilled water groups.
Conclusion: The results demonstrate the antagonistic effect of astaxanthin against the ethanol‐induced facilitation of CSD propagation. Probably carotenoid antioxidant properties are involved in such effects.
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