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1.
Antonie Van Leeuwenhoek ; 111(6): 981-994, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29236232

RESUMO

Paecilomyces variotii is a filamentous fungus that occurs worldwide in soil and decaying vegetation. Optimization of the fermentation process for exopolysaccharide (EPS) production from the fungus P. variotii, structure determination and immuno-stimulating activity of EPS were performed. Response surface methodology (RSM) coupled with central composite design (CCD) was used to optimize the physical and chemical factors required to produce EPS in submerged fermentation. Preliminary investigations to choose the three factors for the present work were made using a factorial experimental design. Glucose, ammonium nitrate (NH4NO3) and pH were used as variables for which, with constant temperature of 28 °C and agitation of 90 rpm, the optimal process parameters were determined as glucose values of 0.96%, NH4NO3 0.26% and pH 8.0. The three parameters presented significant effects. In this condition of culture, the main composition of the isolated EPS was a linear ß-(1 â†’ 6)-linked-D-glucan, as determined by Nuclear Magnetic Resonance (NMR) and methylation analysis. This polysaccharide is a very unusual as an EPS from fungi, especially a filamentous fungus such as P. variotii. Murine peritoneal macrophages cultivated with ß-glucan for 6 and 48 h showed an increase in TNF-α, IL-6 and nitric oxide release with increased polysaccharide concentrations. Therefore, we conclude that the ß-(1 â†’ 6)-linked-D-glucan produced in optimised conditions of P. variotii cultivation has an immune-stimulatory activity on murine macrophages.


Assuntos
Glucanos/metabolismo , Paecilomyces/metabolismo , Polissacarídeos Bacterianos/metabolismo , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética
2.
Int J Biol Macromol ; 105(Pt 2): 1391-1400, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28867226

RESUMO

Several bioactive sulfated galactans have been isolated from the tunic of different species of ascidians. The biological activity of this kind of polysaccharides has been related with the presence and position of sulfate groups, and by the chemical composition of this kind of polysaccharides. A sulfated galactan (1000RS) was isolated from the tunic of the Brazilian ascidia Microcosmus exasperatus through proteolytic digestion, ethanol precipitation, dialysis and freeze-thaw cycles. Homogeneity and molecular weight were estimated by using size exclusion chromatography. Monosaccharide composition and type of linkage were assessed by Gas chromatography coupled to mass spectrometry and the sulfate content was quantified through gelatin/BaCl2 method. These experiments along with NMR and FTIR analysis allowed to claim that the galactan backbone is mainly composed of 4-linked α-l-Galp units. In addition, they permitted to establish that some of the galactose residues are sulfated at the 3-position. This sulfated polysaccharide, which has an average molecular mass of 439.5kDa, presents anticoagulant effect in a dose-dependent manner through the inhibition of the intrinsic coagulation pathway.


Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Galactanos/química , Galactanos/farmacologia , Sulfatos/química , Urocordados/química , Animais , Relação Dose-Resposta a Droga , Humanos , Metilação
3.
Int J Med Mushrooms ; 18(4): 313-20, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27481297

RESUMO

Ganoderma australe was studied to determine the composition of the cell wall, and polysaccharide fraction SK5 was obtained after freeze-thawing an aqueous 5% potassium hydroxide extraction. The monosaccharide composition of the SK5 fraction revealed by gas chromatography-mass spectrometry showed 81.3% glucose, and analyses by 13C nuclear magnetic resonance spectroscopy confirmed a ß-glucan with glycosidic links of the (1→3)-ß type and most likely 4-O substituted. In addition, the biological effect of the ß-glucan from G. australe was evaluated via in vitro cell cultures of peritoneal macrophages isolated from Swiss mice. Biological assays were assessed for toxicity and cell activation, interleukin-6 cytokine concentrations, and the ability to stimulate phagocytic activity. There was an increase in interleukin-6 by approximately 111% with 1.0 µg/mL of polysaccharide, and phagocyte activity was increased in all concentrations examined, obtaining 52.3% with 0.25 µg/mL polysaccharide. The results indicate that a ß-(1→3)-glucan isolated from G. australe can be classified as a biological response modifier.


Assuntos
Ganoderma/química , Fatores Imunológicos/farmacologia , Interleucina-6/metabolismo , Fagocitose/efeitos dos fármacos , Polissacarídeos/farmacologia , beta-Glucanas/farmacologia , Animais , Parede Celular/química , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/imunologia , Camundongos
4.
Appl Biochem Biotechnol ; 175(2): 988-95, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25351631

RESUMO

We studied the production of rhamnolipids by Pseudomonas aeruginosa UFPEDA 614 in submerged culture, using glycerol as the carbon source. A rhamnolipid yield of 15.9 g/L was obtained with 40 g/L glycerol and 5 g/L sodium nitrate as nitrogen source after 7 days of cultivation. Structural analysis carried out at different cultivation periods showed that the four major mono-rhamnolipid homologues are present in higher proportion in the first 48 h. Over time, the corresponding four major di-rhamnolipid homologues predominated, representing about 75 % of the total rhamnolipids after 96 h. Physicochemical analysis of the rhamnolipid mixtures obtained at different cultivation periods showed that the sample obtained from the first day of cultivation had the lower critical micelle concentration (15.6 mg/L), which is probably related to the higher proportion of mono-rhamnolipids. The results presented here show that the composition of the mixture of rhamnolipid homologues produced by P. aeruginosa UFPEDA 614 varies over time and that this variation influences the physicochemical properties of the mixture. These findings can be used in order to produce rhamnolipid mixtures that have suitable properties for different applications.


Assuntos
Técnicas de Cultura/métodos , Glicolipídeos/biossíntese , Glicolipídeos/química , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/metabolismo , Cinética , Micelas , Propriedades de Superfície
5.
Appl Microbiol Biotechnol ; 89(5): 1395-403, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21080163

RESUMO

Rhamnolipid biosurfactants are attracting attention due to their low toxicity, high biodegradability, and good ecological acceptability. However, production in submerged culture is made difficult by severe foaming problems. Solid-state cultivation (SSC) is a promising alternative production method. In the current work, we report the optimization of rhamnolipid production by Pseudomonas aeruginosa UFPEDA 614 on a solid substrate containing sugarcane bagasse and corn bran. The best rhamnolipid production, 45 g/l of impregnating solution used, was obtained with a 50:50 (m/m) mixture of sugarcane bagasse and corn bran supplemented with an impregnating solution containing 6% (v/v) of each of glycerol and soybean oil. This level is comparable with those of previous studies undertaken in solid-state cultivation; the composition of the biosurfactant is similar, but our medium is cheaper. Our work therefore provides a suitable basis for future studies of the development of an SSC-based process for rhamnolipid production.


Assuntos
Celulose/metabolismo , Glicerol/metabolismo , Glicolipídeos/metabolismo , Pseudomonas aeruginosa/metabolismo , Óleo de Soja/metabolismo , Fibras na Dieta , Fermentação , Saccharum , Zea mays
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