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Mushroom polysaccharides consist of a unique set of polymers that arrive intact in the human large intestine becoming available for fermentation by resident gut bacteria with potential benefits to the host. Here we have obtained four glucans from two mushrooms (Pholiota nameko and Pleurotus pulmonarius) under different extraction conditions and their fermentation profile by human gut bacteria in vitro was evaluated. These glucans were isolated and characterized as (1 â†’ 3),(1 â†’ 6)-ß-D-glucans varying in branching pattern and water-solubility. An aliquot of each (1 â†’ 3),(1 â†’ 6)-ß-D-glucan was subjected to controlled smith degradation process in order to obtain a linear (1 â†’ 3)-ß-D-glucan from each fraction. The four ß-D-glucans demonstrated different water solubilities and molar mass ranging from 2.2 × 105 g.mol-1 to 1.9 × 106 g.mol-1. In vitro fermentation of the glucans by human gut microbiota showed they induced different short chain fatty acid production (52.0-97.0 mM/50 mg carbohydrates), but an overall consistent high propionate amount (28.5-30.3 % of total short chain fatty acids produced). All glucans promoted Bacteroides uniformis, whereas Anaerostipes sp. and Bacteroides ovatus promotion was strongly driven by the ß-D-glucans solubility and/or branching pattern, highlighting the importance of ß-D-glucan discrete structures to their fermentation by the human gut microbiota.

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En esta Parte 4 de la serie de cuatro artículos sobre micetismos se analizan los síndromes que se caracterizan por presentar un período de latencia muy corto, con la aparición de síntomas complejos en menos de 6 horas después de la ingestión de los macromicetos. Se discuten los siguientes micetismos: 1) Toxíndrome muscarínico o colinérgico periférico por especies de Inocybe y Clitocybe. 2) Toxíndrome inmunohemolítico o hemolítico por Paxillus. 3) Toxíndrome neumónico alérgico por Lycoperdon perlatum y por Pholiota nameko. 4) Toxíndrome panterínico o neurotóxico glutaminérgico por compuestos isoxazólicos o síndrome pantherina/muscaria. 5) Toxíndrome coprínico o cardiovascular. 6) Toxíndrome neurotóxico alucinogénico por psilocibina y derivados indólicos. 7) Toxíndrome psicotrópico por estirilpironas y gimnopilinas de Gymnopilus spectabilis o G. junonius. 8) Toxíndrome agudo de rabdomiólisis por Russula subnigricans. 9) Toxíndrome cianogénico por Marasmius oreades. 10) Toxíndrome inmunosupresor por tricotecenos macrocíclicos de Podostroma cornu-damae. 11) Toxíndrome hemolítico debido a ostreolisina de Pleurotus ostreatus y especies relacionadas. Se analizan los síntomas, las toxinas involucradas, los mecanismos de acción, cuando se conocen, y las especies causantes de los micetismos.

This Part 4 of the series of four articles on mushroom poisonings refers to early-onset syndromes, which are characterized by a very short latency period, and the appearance of complex symptoms in less than 6 hours after mushroom ingestion. The following mycetisms are discussed, (1) Peripheral cholinergic, or muscarinic syndrome due to Inocybe and Clitocybe species. (2) Immunohaemolytic or haemolytic syndrome by Paxillus. (3) Allergic pneumonic syndrome due to Lycoperdon perlatum, and Pholiota nameko. (4) Glutaminergic neurotoxic, or pantherinic syndrome by isoxazole compounds or pantherina/muscaria syndrome. (5) Coprinic or cardiovascular syndrome. (6) Hallucinogenic neurotoxic syndrome due to psilocybin and indole derivatives. (7) Psychotropic syndrome by styrylpirones and gymnopilins of Gymnopilus spectabilis or G. junonius. (8) Rhabdomyolysis acute syndrome due to Russula subnigricans. (9) Cyanogenic syndrome by Marasmius oreades. (10) Immunosuppressive syndrome by macrocyclic trichothecenes of Podostroma cornu-damae. (11) Haemolytic syndrome due to ostreolisine of Pleurotus ostreatus, and related species. The symptoms, toxins involved, mechanisms of action, when known, and the species of mushrooms responsible for the mycetisms are analyzed.

Nesta parte 4 da série de quatro artigos sobre intoxicação por cogumelos são analisadas síndromes que se caracterizam por apresentar um período de latência muito breve, com aparecimento de sintomas complexos em menos de 6 horas após a ingestão dos macromicetos. As seguintes intoxicações com cogumelos são discutidas: (1) Toxíndrome muscarínico ou colinérgico periférico por espécies de Inocybe e Clitocybe. (2) Toxíndrome imuno-hemolítica ou hemolítica por Paxillus. (3) Toxíndrome pneumônica alérgica por Lycoperdon perlatum e por Pholiota nameko. (4) Toxíndrome panterínica ou neurotóxica glutaminérgica por compostos isoxazólicos ou síndrome pantherina/muscaria. (5) Toxíndrome coprínica ou cardiovascular (6) Toxíndrome neurotóxico-alucinogênica por psilocibina e derivados indólicos. (7) Toxíndrome psicotrópica por estirilpironas e gimnopilinas de Gymnopilus spectabilis ou G. junonius. (8) Toxíndrome aguda de rabdomiólise por Russula subnigricans. (9) Toxíndrome cianogênica por Marasmius oreades. (10) Toxíndrome imunossupressora por tricotecenos macrocíclicos de Podostroma cornu-damae. (11) Síndrome hemolítica por ostreolisina de Pleurotus ostreatus e espécies relacionadas. São analisados os sintomas, as toxinas envolvidas, os mecanismos de ação, quando conhecidos, e as espécies de cogumelos responsáveis pelas intoxicações.

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A ß-D-glucan was obtained from the edible mushroom Pholiota nameko by hot aqueous extraction and purification. NMR and methylation analyses of the purified fraction (GHW-PN, 1.46% yield) indicated the presence of a (1 → 3)-linked ß-D-glucan, highly substituted (~27%) at O-6 by single units of ß-D-Glcp or by (1 → 6)-ß-D-Glcp fragments. The ß-glucan (at 0.5, 1, and 2%) showed shear thinning behavior and when the concentration of the solution increased, there was an increase in apparent viscosity. The ß-D-glucan presented gel-like behavior and thermal stability under a simulated pasteurization process, suggesting its potential as a thickening and gelling agent in products submitted to temperature variations. The ß-D-glucan at 0.3, 1.0 and 3.0 mg kg-1 significantly inhibited the inflammatory pain in 24.8, 56.9 and 82.3%, respectively, in the formalin-induced nociception in mice. The results pointed out that the ß-D-glucan (GHW-PN) isolated from P. nameko presents potential application for the food industry or for medical purposes.

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RESUMO

A crude fraction (SCW) was extracted with cold water from Pholiota nameko and showed mannose (24.1%), galactose (44.9%) and glucose (31%). Purification procedures resulted in a polysaccharide fraction (bG-PN), that showed only glucose. NMR and methylation analyses of bG-PN indicated a ß-d-glucan-(1→3)-linked, substituted at O-6 by ß-d-Glcp or (1→6)-linked ß-d-Glcp side chains. Rheological studies of crude and purified fractions at the same concentration showed similar shear-thinning behavior and gel-like structure which indicates no need to isolate the polymer to achieve some desirable rheological properties. SCW (at 1% and 2%) and bG-PN (at 2%) presented thermal stability during heating and cooling, suggesting that the physical structure of gels (SCW and bG-PN at 2%) and viscoelastic fluid (SCW at 1%) formed were not altered in the tested temperature range. Our results suggest that P. nameko ß-d-glucans can be applied in different food preparations as thickener or gelling agents modifying their rheological properties.

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