P.A.J. Gorin

A 3-O-methylated mannogalactan from Pleurotus pulmonarius: structure and antinociceptive effect.

A polysaccharide (Mw 2.39x10(4)g/mol) was extracted with cold water from the basidiomycete Pleurotus pulmonarius, and its antinociceptive and anti-inflammatory properties were evaluated. It was a mannogalactan (MG), whose structure was characterized using mono- and two-dimensional NMR spectroscopy, methylation analysis, and a controlled Smith degradation. It had a main chain of (1-->6)-linked alpha-D-galactopyranosyl and 3-O-methyl-alpha-D-galactopyranosyl units, both of which are partially substituted at O-2 by beta-D-mannopyranosyl non-reducing ends. The MG was tested for its effects on the acetic acid-induced writhing reaction in mice, a typical model for inflammatory pain, causing a marked and dose-dependent inhibition of the nociceptive response, with ID50 of 16.2 (14.7-17.7)mg/kg and inhibition of 93+/-3% at a dose of 30mg/kg. An inflammatory response was not inhibited.

Polysaccharides from peach pulp: Structure and effects on mouse peritoneal macrophages

Pulp from peaches contained polygalacturonic acid and arabinogalactan as main polysaccharides, which were isolated and characterised. The polygalacturonic acid (AE-CWI) contained 95% GalA and its (13)C NMR spectrum showed signals at δ 98.9, 78.0, 71.4, 69.1, 68.4, and 175.1 from C-1, C-4, C-5, C-3, C-2, and C-6 respectively, from (1→4)-linked α-GalpA units. Methylation-MS analysis of carboxy-reduced material (AE-CWI-CR) gave 90% of 2,3,6-Me(3)-galactitol acetate. The arabinogalactan (AE-AG) was composed mainly of Ara (41%) and Gal (50%) and was characterised (methylation analysis and (13)C NMR) as a type II-arabinogalactan. It induced peritoneal macrophage activation in mice, ~70% of cells treated with this fraction (1-50 μg/mL) having morphology of activated cells. However, NO production in macrophages treated with AE-AG was not affected. This suggests a new biological activity for peach polysaccharides.

Galactomannan, lichenan and Isolichenan from the polysaccharide -rich lichen Newropogon aurantiaco-ater

Abstract Newropogon aurantiaco-ater contains 56% of polysaccharide, from which lichenan (26%) was isolated in very large amounts, along with isolichenan (4%) and a galactomannan (1 %). The galactomannan consists mainly of a (1 →6)-Iinked α- d -Manp main-chain partly substituted at 0-2 with α- d -Galp units, the virtual absence of β- d -Galp units being unusual in a lichen galactomannan. Arabinitol (3%) is also present.

O-Methylated mannogalactan from the microalga Coccomyxa mucigena, symbiotic partner of the lichenized fungus Peltigera aphthosa.

A structural study of the carbohydrates from Coccomyxa mucigena, the symbiotic algal partner of the lichenized fungus Peltigera aphthosa, was carried out. It produced an O-methylated mannogalactan, with a (1-->6)-linked beta-galactopyranose main-chain partially substituted at O-3 by beta-Galp, 3-OMe-alpha-Manp or alpha-Manp units. There were no similarities with polysaccharides previously found in the lichen thallus of P. aphthosa. Moreover, the influence of lichenization in polysaccharide production by symbiotic microalgae and the nature of the photobiont in carbohydrate production in lichen symbiosis are also discussed.

Some biomolecules and a partially O-acetylated exo-galactomannan containing β-Galf units from pathogenic Exophiala jeanselmei, having a pronounced immunogenic response.

The pathogenic fungus Exophiala jeanselmei (Ej4) was grown in submerged MM medium, glucose being consumed after six days with maximum biomass and EPS production. Cells were extracted with CHCl3-MeOH (2:1, v/v) yielding a product containing 10% lipid, with high levels of unsaturated C(18:1) (43.6%) and C(18:2) (21.0%), 2D-TLC showed the presence of PE (17.7%), PS (11.6%), PC (35.8%), PI (1.2%) and lyso-phospholipids, LPE (10.7%), LPC (2.0%), PA (10.4%), cardiolipin (10.5%) and glucosyl-ceramide. Analysis of EPS-1 (120 kDa) showed a galactomanan, containing a main chain of Manp-(1→2) (24.2%), substituted by side chains containing terminal Galf (16.8%) and Manp (3.5%) and acetyl groups attached at O-6 of terminal Galf. An immune response against antigens was obtained using Balb/C mice. Anti-EPS-1 antibodies recognized purified fraction containing cellular walls very titer and higher than 1:20,000 for EPS. The studied biomolecules showed biotechnological potential and point to important perspectives in diagnosis of fungi and immunomodulatory products.

Does aposymbiotically cultivated fungus Ramalina produce isolichenan

The main α-glucan synthesized by lichens of the genera Ramalina in the symbiotic state is isolichenan. This polysaccharide was not found in the aposymbiotically cultivated symbionts. It is still unknown if this glucan is produced by the mycobiont only in the presence of a photobiont, in a lichen thallus, or if the isolichenan suppression is influenced by the composition of culture medium used in its aposymbiotic cultive. Consequently, the latter hypothesis is tested in this study. Cultures of the mycobiont Ramalina complanata were obtained from germinated ascospores and cultivated on 4% glucose Lilly and Barnett medium. Freeze-dried colonies were defatted and their carbohydrates extracted successively with hot water and aqueous 10% KOH, each at 100 °C. The polysaccharides nigeran, laminaran and galactomannan were liberated, along with a lentinan-type β-glucan and a heteropolysaccharide (Man : Gal : Glc, 21 : 28 : 51). Nevertheless, the α-glucan isolichenan was not found in the extracts. It follows that it was probably a symbiotic product, synthesized by the mycobiont only in this particular microenvironment, in the presence of the photobiont in the lichen thallus. A discussion about polysaccharides found in the symbiotic thallus as well as in other aposymbiotic cultivated Ramalina mycobionts is also included.