RESUMO
BACKGROUND: The present study combines morphological and anatomical studies, cell wall chemical composition analysis, as well as assessment of the nutritional value of Guadua chacoensis foliage leaves. RESULTS: Foliage leaves of G. chacoensis are a promising source of forage because: (a) as a native woody bamboo, it is adapted to and helps maintain environmental conditions in America; (b) leaf anatomical studies exhibit discontinuous sclerenchyma, scarcely developed, while pilose indumentum, silica cells, prickles and hooks are also scarce; (c) it has a high protein content, similar to that of Medicago sativa, while other nutritional parameters are similar to those of common forages; and (d) glucuronoarabinoxylan, the major extracted polysaccharide, has one-third of the 4-linked ß-d-xylopyranosyl units of the backbone substituted mainly with α-l-arabinofuranose as single stubs or non-reducing end of short chains, but also 5-linked α-l-arabinofuranose units, terminal ß-d-xylopyranose and d-galactopyranose units, as well as α-d-glucuronic acid residues and small amounts of its 4-O-methylated derivative. CONCLUSION: These results constitute the first report on this species, and as culms are utilized in constructions and crafts, the remaining leaves, when used as forage, constitute a byproduct that allows an additional income opportunity. © 2016 Society of Chemical Industry.
Assuntos
Ração Animal , Parede Celular/química , Dieta/veterinária , Valor Nutritivo , Folhas de Planta , Poaceae , Ruminantes , América , Animais , Arabinose/análogos & derivados , Arabinose/análise , Conservação dos Recursos Naturais , Carboidratos da Dieta/análise , Fibras na Dieta/análise , Proteínas Alimentares/análise , Galactose/análise , Ácido Glucurônico/análise , Células Vegetais/química , Folhas de Planta/anatomia & histologia , Folhas de Planta/química , Proteínas de Plantas/análise , Poaceae/anatomia & histologia , Poaceae/química , Madeira , Xilanos/análise , Xilose/análogos & derivados , Xilose/análiseRESUMO
Efficient synthesis of 3-deoxy-1,2-O-isopropylidene-ß-D- and ß-L-threo-pentofuranose (1,2-O-isopropylidene-ß-D- and ß-L-cordycepose) was accomplished starting from D- and L-arabinofuranose derivatives, respectively, by the action of LiBH(Et)3 on corresponding intermediate 3-O-lyxofuranosyl trifluoromethanesulfonates.
Assuntos
Arabinose/análogos & derivados , Oxigênio/química , Arabinose/química , Estereoisomerismo , Especificidade por SubstratoRESUMO
The Salmonella enterica serovar Typhimurium lipopolysaccharide consisting of covalently linked lipid A, non-repeating core oligosaccharide, and the O-antigen polysaccharide is the most exposed component of the cell envelope. Previous studies demonstrated that all of these regions act against the host immunity barrier. The aim of this study was to define the role and interaction of PmrAB-dependent gene products required for the lipopolysaccharide component synthesis or modification mainly during the Salmonella infection. The PmrAB two-component system activation promotes a remodeling of lipid A and the core region by addition of 4-aminoarabinose and/or phosphoethanolamine. These PmrA-dependent activities are produced by activation of ugd, pbgPE, pmrC, cpta, and pmrG transcription. In addition, under PmrA regulator activation, the expression of wzz(fepE) and wzz(st) genes is induced, and their products are required to determine the O-antigen chain length. Here we report for the first time that Wzz(st) protein is necessary to maintain the balance of 4-aminoarabinose and phosphoethanolamine lipid A modifications. Moreover, we demonstrate that the interaction of the PmrA-dependent pbgE(2) and pbgE(3) gene products is important for the formation of the short O-antigen region. Our results establish that PmrAB is the global regulatory system that controls lipopolysaccharide modification, leading to a coordinate regulation of 4-aminoarabinose incorporation and O-antigen chain length to respond against the host defense mechanisms.
Assuntos
Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Lipídeo A/química , Lipopolissacarídeos/metabolismo , Antígenos O/metabolismo , Salmonella typhimurium/metabolismo , Fatores de Transcrição/metabolismo , Sequência de Aminoácidos , Animais , Arabinose/análogos & derivados , Arabinose/química , Proteínas do Sistema Complemento/química , Humanos , Macrófagos/metabolismo , Camundongos , Dados de Sequência Molecular , Mutação , Mapeamento de Interação de ProteínasRESUMO
The aerial parts of Cuphea carthagenensis (Jacq.) J.F. Macbride (Lythraceae) are traditionally employed in Brazil to treat cardiovascular diseases. The aim of this study was to compare preparations of C. carthagenensis aerial parts (aqueous and ethanol extracts, together with derived fractions) with regard to their total phenolic contents and in vitro vasodilating activity. The main flavonoids found in the extracts were isolated and identified as quercetin derivatives. The extracts and fractions showed similar HPLC profiles with the presence of quercetin-5-O-ß-glucopyranoside, quercetin-3-O-α-arabinofuranoside and quercetin-3-sulfate in all of them, but marked differences in the contents of flavonoids, proanthocyanidins, tannis and total phenolics. Excepting the aqueous extract, all assayed preparations elicited vasodilatation on pre-contracted rat aortic rings in the range of pIC(50) 4.53±0.03 to 4.98±0.06. Polynomial regression analysis demonstrated the relationship between vasodilating activity and the contents of flavonoids (r(2)=0.5190), proanthocyanidins (r(2)=0.8016), tannins (r(2)=0.8041) and total phenolics (r(2)=0.6226), suggesting the participation of these compounds in the pharmacological effect and their potential use as chemical markers for the species.
Assuntos
Cuphea/química , Flavonoides/farmacologia , Fenóis/farmacologia , Extratos Vegetais/farmacologia , Vasodilatação/efeitos dos fármacos , Animais , Arabinose/análogos & derivados , Arabinose/química , Arabinose/farmacologia , Cromatografia Líquida de Alta Pressão , Sinergismo Farmacológico , Flavonoides/química , Flavonoides/isolamento & purificação , Glucosídeos/química , Glucosídeos/farmacologia , Masculino , Fenóis/isolamento & purificação , Componentes Aéreos da Planta/química , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Proantocianidinas/isolamento & purificação , Proantocianidinas/farmacologia , Quercetina/análogos & derivados , Quercetina/química , Quercetina/isolamento & purificação , Quercetina/farmacologia , Ratos , Ratos Wistar , Análise de Regressão , Taninos/isolamento & purificação , Taninos/farmacologiaRESUMO
Mycolyl-arabinogalactan (mAG) complex is a major component of the cell wall of Mycobacterium tuberculosis, the causative agent of tuberculosis disease. Due to the essentiality of the cell wall for mycobacterium viability, knowledge of the biosynthesis of the arabinogalactan is crucial for the development of new therapeutic agents. In this context, we have synthesized two new branched arabinogalactafuranose tetrasaccharides, decenyl ß-D-Galf-(1â5)-ß-D-Galf-(1â6)[α-D-Araf(1â5)]-ß-D-Galf (1) and decenyl ß-D-Galf-(1â6)-[α-D-Araf-(1â5)]-ß-D-Galf-(1â5)-ß-D-Galf (2), as interesting tools for arabinofuranosyl transferase studies. The aldonolactone strategy for the introduction of the internal d-Galf was employed, allowing the construction of oligosaccharides from the non-reducing to the reducing end. Moreover, a one-pot procedure was developed for the synthesis of trisaccharide lactone 21, precursor of 2, which involved a glycosylation-deprotection-glycosylation sequence, through the use of TMSOTf as catalyst of the trichloroacetimidate method as well as promoter of TBDMS deprotection.
Assuntos
Antibacterianos/química , Arabinose/análogos & derivados , Furanos/química , Galactanos/química , Galactose/química , Arabinose/síntese química , Estrutura MolecularRESUMO
The soft rot fungus Penicillium purpurogenum grows on a variety of natural substrates and secretes various isoforms of xylanolytic enzymes, including three arabinofuranosidases. This work describes the biochemical properties as well as the nucleotide and amino acid sequences of arabinofuranosidase 3 (ABF3). This enzyme has been purified to homogeneity. It is a glycosylated monomer with a molecular weight of 50,700 and can bind cellulose. The enzyme is active with p-nitrophenyl alpha-L-arabinofuranoside and p-nitrophenyl beta-D-xylopyranoside with a K(m) of 0.65 mM and 12 mM, respectively. The enzyme is active on xylooligosaccharides, yielding products of shorter length, including xylose. However, it does not hydrolyze arabinooligosaccharides. When assayed with polymeric substrates, little arabinose is liberated from arabinan and debranched arabinan; however, it hydrolyzes arabinose and releases xylooligosaccharides from arabinoxylan. Sequencing both ABF3 cDNA and genomic DNA reveals that this gene does not contain introns and that the open reading frame is 1,380 nucleotides in length. The deduced mature protein is composed of 433 amino acids residues and has a calculated molecular weight of 47,305. The deduced amino acid sequence has been validated by mass spectrometry analysis of peptides from purified ABF3. A total of 482 bp of the promoter were sequenced; putative binding sites for transcription factors such as CreA (four), XlnR (one), and AreA (three) and two CCAAT boxes were found. The enzyme has two domains, one similar to proteins of glycosyl hydrolase family 43 at the amino-terminal end and a family 6 carbohydrate binding module at the carboxyl end. ABF3 is the first described modular family 43 enzyme from a fungal source, having both alpha-L-arabinofuranosidase and xylobiohydrolase functionalities.
Assuntos
Proteínas Fúngicas/isolamento & purificação , Proteínas Fúngicas/metabolismo , Glicosídeo Hidrolases/isolamento & purificação , Glicosídeo Hidrolases/metabolismo , Penicillium/enzimologia , Arabinose/análogos & derivados , Arabinose/metabolismo , Celulose/metabolismo , DNA Fúngico/química , DNA Fúngico/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/genética , Glicosídeos/metabolismo , Cinética , Espectrometria de Massas , Dados de Sequência Molecular , Peso Molecular , Oligossacarídeos/metabolismo , Fases de Leitura Aberta , Penicillium/genética , Regiões Promotoras Genéticas , Ligação Proteica , Análise de Sequência de DNA , Xilosidases/química , Xilosidases/genética , Xilosidases/isolamento & purificação , Xilosidases/metabolismoRESUMO
Thiodisaccharides having beta-D-Galf or alpha-L-Araf units as non-reducing end have been synthesized by the SnCl(4)- or MoO(2)Cl(2)-promoted thioglycosylation of per-O-benzoyl-D-galactofuranose (1), its 1-O-acetyl analogue 4, or per-O-acetyl-alpha-L-arabinofuranose (16) with 6-thioglucose or 6-thiogalactose derivatives. After convenient removal of the protecting groups, the free thiodisaccharides having the basic structure beta-D-Galf(1-->6)-6-thio-alpha-D-Glcp-OMe (5) or beta-D-Galf(1-->6)-6-thio-alpha-D-Galp-OMe (15) were obtained. The respective alpha-L-Araf analogues 18 and 20 were prepared similarly from 16. Alternatively, beta-D-Galf(1-->4)-4-thio-3-deoxy-alpha-L-Xylp-OiPr was synthesized by Michael addition to a sugar enone of 1-thio-beta-d-Galf derivative, generated in situ from the glycosyl isothiourea derivative of 1. The free S-linked disaccharides were evaluated as inhibitors of the beta-galactofuranosidase from Penicillium fellutanum, being 15 and 20 the more active inhibitors against this enzyme.
Assuntos
Arabinose/análogos & derivados , Dissacarídeos/síntese química , Inibidores Enzimáticos/síntese química , Glicosídeo Hidrolases/antagonistas & inibidores , Penicillium/enzimologia , Arabinose/química , Catálise , Compostos Clorados/química , Dissacarídeos/química , Dissacarídeos/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Galactose/química , Glicosídeo Hidrolases/metabolismo , Compostos de Manganês/química , Óxidos/química , Penicillium/metabolismo , Sulfetos/química , Compostos de Estanho/químicaRESUMO
Three new flavonol arabinosides (2-4) were isolated from the young leaves of Calycolpus warszewiczianus. The structures were determined as myricetin-3-O-alpha-L-3' '-acetylarabinofuranoside (2), myricetin-3-O-alpha-L-3' ',5' '-diacetylarabinofuranoside (3), and 5-galloylquercetin-3-O-alpha-L-arabinofuranoside (4). Molecular structures were elucidated using NMR spectroscopy in combination with IR and MS data. Two known compounds, myricetin-3-O-alpha-L-arabinofuranoside (1) and (-)-epi-catechin (5), were also isolated. The compounds were tested in vitro against a chloroquine-resistant strain of Plasmodium falciparum, Leishmania mexicana, and Trypanosoma cruzi parasites. Compound 4 demonstrated weak activity against a chloroquine-resistant strain of P. falciparum (14.5 microM), whereas none of the compounds demonstrated activity against L. mexicana and T. cruzi at the concentrations of 40 and 50 microg/mL, respectively, and no cytotoxicity was detected against mammalian cells below 100 microg/mL.
Assuntos
Antimaláricos , Arabinose , Flavonóis , Myrtaceae/química , Plantas Medicinais/química , Animais , Antimaláricos/química , Antimaláricos/isolamento & purificação , Antimaláricos/farmacologia , Antiprotozoários/química , Antiprotozoários/isolamento & purificação , Antiprotozoários/farmacologia , Arabinose/análogos & derivados , Arabinose/química , Arabinose/isolamento & purificação , Arabinose/farmacologia , Cloroquina/farmacologia , Relação Dose-Resposta a Droga , Resistência a Medicamentos , Flavonóis/química , Flavonóis/isolamento & purificação , Flavonóis/farmacologia , Leishmania mexicana/efeitos dos fármacos , Estrutura Molecular , Panamá , Plasmodium falciparum/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacosRESUMO
A new stemodinoside, stemodin-alpha-L-arabinofuranoside (5), was isolated from the plant Stemodia maritima. Incubation of stemodin (2) with Rhizopus oryzae ATCC 11145 gave 2 alpha,7 beta,13(S)-trihydroxystemodane (17) and 2 alpha,3 beta,13(S),16 alpha-tetrahydroxystemodane (18) whilst stemodinone (8) afforded 6 alpha,13(S)-dihydroxystemodan-2-one (19). The bioconversion of 2 beta,13(S)-dihydroxystemodane (10) by the fungus yielded 2 beta,7 beta,13(S)-trihydroxystemodane (20) whereas stemod-12-en-2-one (9) provided 7 beta,17-dihydroxystemod-12-en-2-one (21). The results provide useful information about the relationship between the functional groups of the substrates and their potential for bioconversion.