P A Gorin

Universidade Federal do Paraná, Curitiba, Estado do Parana, Brazil

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Publications (55)120.35 Total impact

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    ABSTRACT: Two distinct sulfonoglycolipid fractions were isolated from the basidiolichen Dictyonema glabratum by chromatography on Diethylaminoethyl (DEAE)-Sepharose, which resulted in rapid elution, followed by partition between aqueous sulfuric acid and an ethyl acetate-methanol-chloroform mixture and the content of the organic layer chromatographed of a column of silicic acid. The products were examined by nuclear magnetic resonance spectroscopy in their native rather than their acetylated forms, as in previous investigations. Each was methanolyzed to give the same methyl glycoside, Me-G. On electrospray ionization mass spectrometry (ESI-MS), it provided a pseudomolecular ion at m/z 303 in the positive-ion mode and a molecular ion at m/z 257 with a daughter ion at m/z 146 in the negative-ion mode, showing the presence of a sulfonate group S-linked to a hexosyl ring. An exclusively alpha-glucopyranosyl configuration was indicated by (1)H, (1)H correlation spectroscopy (COSY) and (1)H, (1)H total correlation spectroscopy (TOCSY). S-substitution occurred at CH(2)-6, because a high-field (13)C signal at delta 52.6 gave an inverted distortionless enhancement by polarization transfer (DEPT) signal and (1)H, (3)C heteronuclear multiple quantum coherence (HMQC) showed correlation with two H-6 signals. This 6-sulfono-alpha-quinovopyranoside group was present in the glycolipid fractions, O-alpha-D-Quip-6-sulfono-(1'<-->1)-2,3-diacyl-D-glycerol (polar fraction 1a; PF1a) and O-alpha-D-Quip-6-sulfono-(1'<-->1)-2- or -3-monoacyl-D-glycerol (polar fraction 1b; PF1b), the monoacyl derivatives not having been previously completely characterized in other systems. All components are typical of plant glycolipids. The most abundant fatty acid ester in PF1a and PF1b was C(16:0). Other esters present in PF1a were C(14:0), C(17:0), C(18:0), C(18:1) (oleic), C(20:0), C(21:0), and C(24:0), in contrast with C(14:0), C(17:0), C(18:0), and C(20:0) in PF1b. HMQC and TOCSY data can be used as fingerprints for detection of glycosylacylglycerides and sulfonoglycolipids and the positive ESI-MS ions at m/z 329 and 271 for identification of the latter.
    Glycobiology 05/2001; 11(4):345-51. · 3.75 Impact Factor
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    ABSTRACT: A mixture of two lyso isomers of a galactolipid was obtained from Dictyonema glabratum. Aqueous hydrolysis gave rise to galactose and glycerol in a 3:1 molar ratio. ESI-MS spectroscopy gave, in the positive-ion mode, a pseudomolecular ion at m/z 839 and daughter ions with m/z 677, 600, 515 and 353, suggesting three galactosyl units linked to a glycerol moiety, substituted by one O-acyl group. 1D and 2D NMR experiments were used to characterize the glycolipid, and HMQC examination showed three anomeric signals, corresponding to two alpha-Galp and one beta-Galp residue liked to glycerol. The glycolipid structure was shown to be O-alpha-D-Galp-(1-->6)-O-alpha-D-Galp-(1-->6)-O-beta-D-Galp-(1<-->1)-2- and -3-monoacyl-D-glycerol, the latter structures not having been previously found in nature. The fatty acid composition was determined by GC-MS of derived methyl esters: that of palmitic acid C(16:0) was the most abundant, although the presence of C(12:0), C(14:0), C(16:1) and C(18:0) esters was observed.
    FEMS Microbiology Letters 01/2001; 194(2):155-8. · 2.72 Impact Factor
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    ABSTRACT: Beta-D-glucans of the laminaran type were prepared from 15 Cladonia spp., Cladonia bellidiflora, Cladonia boryi, Cladonia clathrata, Cladonia connexa, Cladonia crispatula, Cladonia furcata, Cladonia gracilis, Cladonia ibitipocae, Cladonia imperialis, Cladonia miniata, Cladonia penicillata, Cladonia salmonea, Cladonia signata, Cladonia substellata and Cladonia uncialis. They were extracted with 10% aqueous KOH at 100 degrees C, giving polysaccharides with varying yields and proportions of mannose, galactose and glucose. Their aqueous solutions were freeze-thawed giving precipitates of mixed alpha-glucan (nigeran) and beta-glucans, which were isolated and suspended in aqueous 0.5% KOH at 50 degrees C, which preferentially dissolved the beta-glucan. In the case of the C. uncialis product, it was subjected to methylation analysis, which gave rise to 2,4,6-tri-O-methylglucitol acetate only, corresponding to (1-->3)-linkages. Its specific rotation (+4 degrees ) and one- and two-dimensional nuclear magnetic resonance (NMR) spectra were consistent with beta-linkages. 13C and (1)H-1 signals were observed, respectively, at delta 102.8 (C-1), 86.0 (C-3), 76.2 (C-5), 72.6 (C-2), 68.3 (C-4) and 60.7 (C-6), and 4.55 (H-1), 3.31 (H-2), 3.49 (H-3), 3.27 (H-4), 3.27 (H-5), 3.48 (H-6) and 3.72 (H-6'). Similar (13)C-NMR spectra were obtained from the glucans from the other 14 Cladonia spp. The beta-D-glucans of the laminaran type seems to be present in all Cladonia spp. being significant for chemotyping since it was observed in every species studied.
    FEMS Microbiology Letters 01/2001; 194(1):65-9. · 2.72 Impact Factor
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    ABSTRACT: The chemical structures of the glucans, galactoglucomannans and galactomannoglucans of two species of the Cladonia, section Cocciferae, Cladonia miniata and Cladonia salmonea, were determined and compared. alpha-D-Glucans of the nigeran type were isolated from both species, in common with all Cladonia spp., along with galactoglucomannans containing (1-->6)-linked main-chains of alpha-D-Manp units substituted by structurally different and typical side-chains. Isolated were previously unreported galactomannoglucans, with (1-->3)-linked main-chains of beta-D-Glcp units, substituted at O-2,6 by side-chains. These consisted of beta-D-Galf, 6-O-substituted beta-D-Galf and 2-O-, 4-O-, 6-O- and 2, 3-di-O-substituted alpha-D-Manp units. According to (13)C NMR spectroscopy, a similar galactomannoglucan was isolated from the Cladonia spp. Cladonia signata, Cladonia crispatula, Cladonia penicillata, Cladonia imperialis, Cladonia clathrata, Cladonia connexa, Cladonia substellata and Cladonia ibitipocae. Its presence could also contribute to the classic taxonomy of lichenized fungi.
    FEMS Microbiology Letters 01/2000; 181(2):313-7. · 2.72 Impact Factor
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    ABSTRACT: A novel method is described for the determination of sequential side-chain structures in the complex, high-arabinose polysaccharide of the gum exudate of angico branco (Anadenanthera colubrina), using as basis the structurally similar reducing oligosaccharides present in small quantities. Of the ten detected, eight were characterized as disaccharides (2, 3, and 9), linear trisaccharides (1 and 4), branched pentasaccharides (5 and 6), and a doubly branched heptasaccharide (8). The oligosaccharides are substituents of the polysaccharide, which has a (1-->3)-linked beta-D-galactopyranosyl main chain, and with two exceptions they had 6-O-substituted galactopyranosyl reducing ends, probably corresponding to its main-chain units. Characterization was effected through their 1D and 2D NMR correlation spectra, which were better resolved and more readily interpretable than those of the polysaccharide. These spectral data were supported by monosaccharide composition and rotation values. Controlled Smith degradations and methylation analyses were carried out when it was necessary. These data were confirmed by field-desorption MS.
    Carbohydrate Research 08/1999; 320(3-4):167-75. · 1.97 Impact Factor
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    ABSTRACT: Three glycolipids (1-3) were isolated from the basidiolichen Dictyonema glabratum. Their carbohydrate and lipid components were structurally characterized using 1D 1H and 13C and 2D NMR spectroscopy, complemented by mass spectrometry, as were the carbohydrate moieties formed on saponification. These were O-alpha-D-Galp-(1''-->6')-O-beta-D-Galp-(1'<-->1)-2, 3-diacyl-D-glycerol (2) and two others not previously found in lichens, O-beta-D-Galp-(1'<-->1)-2,3-diacyl-D-glycerol (1) and O-alpha-D-Galp-(1'''-->6'')-O-alpha-D-Galp-(1' '-->6')-O-beta-D-Galp-(1'<-->1)-2,3-diacyl-D-glycerol (3). Each was saponified to give the free carbohydrates and its fatty acid methyl esters. The most abundant fatty acid esters in 1-3 was palmitic C16:0, but there was a wide variation of ester composition. Others present were C8:0 and C14:0 in 1, C14:0, C15:0, C17:0, C18:0, C18:1 (oleic), C18:2 (linoleic), C22:0, and C24:0 in 2, and C8:0, C14:0, C18:0, C18:1 (oleic), C18:2 (linoleic), and C18:3 (linolenic) in 3. As in ascolichens, the glycolipids appear to arise from the phycobiont.
    Journal of Natural Products 06/1999; 62(6):844-7. · 3.95 Impact Factor
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    ABSTRACT: The gum from Anadenanthera colubrina consists mainly of a complex high-arabinose heteropolysaccharide with a (1-->3)-linked beta-D-Galp main-chain and many different side-chains. These contain beta-D-Galp-[(1-->6)-beta-D-Galp]m-(1-->6)-, substituted in turn at O-3 by alpha-L-Araf-[(1-->3)-alpha-L-Araf-]0-2. Also present are (1) main-chain units substituted at O-4 and O-6 by alpha-L-Araf units, (2) side-chains of Rhap-(1-->4)-beta-D-GlcpA-(1-->6)-beta-Galp-groups, (3) alpha-L-Arap non-reducing end-units linked (1-->6) to D-Galp, and (4) beta-Araf and beta-Arap structures. For the first time, a plant gum exudate was found to contain in the natural state, reducing low M(r) carbohydrates. These were rhamnose (0.6%), arabinose (4.7%), mannose (0.1%), galactose (0.8%) and many oligosaccharides (0.6%; 11 with different RFs, with the majority containing arabinose). They were all mixtures with the exception of alpha-Rhap-(1-->4)-beta-D-GlcpA-(1-->6)-alpha beta-Gal and an incompletely identified hexasaccharide, probably having alpha-L-Araf-(1-->4)-beta-D-Galp- and -alpha-L-Araf-(1-->3)-beta-D-Galp- structures. The mono- and oligosaccharides do not appear to arise via in situ autohydrolysis of the gum.
    Phytochemistry 05/1998; 47(7):1207-14. · 3.35 Impact Factor
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    ABSTRACT: The gum exudate from the Brazilian cashew-nut tree (Anacardium occidentale) contained traces of the reducing sugars, rhamnose (0.005%), arabinose (0.03%), mannose (0.007%), galactose (0.03%), glucose (0.02%), beta-D-Galp-(1-->6)-alpha beta-D-Gal (0.05%), alpha-L-Rhap-(1-->4)-alpha beta-D-GlcA (0.008%) and alpha-L-Rhap-(1-->4)-beta-D-GlcpA-(1-->6)-beta-D-Galp-(1-->6 )-alpha beta-D-Gal (0.008%). Rhamnose, arabinose, glucose and the three oligosaccharides are components of the side-chains of the gum polysaccharide, which has a main chain of (1-->3)-linked beta-D-Galp units. The structure of this polysaccharide was determined and found to differ from that previously reported for the gum of a tree growing in India, lacking units of 4-O-methylglucuronic acid. Other new side-chain structures were characterized, particularly -alpha-D-Galp-(1-->6)-D-Galp- and alpha-L-Araf-(1-->6)-D-Galp-).
    Phytochemistry 03/1998; 47(5):715-21. · 3.35 Impact Factor
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    ABSTRACT: The most active polysaccharides which show anti-tumoral activity are (1-->3)-beta-D-glucans, branched or not at O-6. Since these structures are sometimes poorly soluble in aqueous media, alpha-D-glucans and their chemical derivatives, which are more soluble, were also studied. The present object is to observe morphological alterations in HeLa cells caused by two different polysaccharides obtained from the lichen Ramalina celastri, which are (1-->3),(1-->4)-linked alpha-D-glucan and its sulphated derivative. The cells were incubated in Eagle's medium in the absence or presence of each polysaccharide and routinely processed and analysed by light and electron microscopy. Even though the alpha-D-glucan altered the cellular volume, cytoplasmic densities, and mitosis, the resulting monolayer was similar to the control. TEM analysis showed cytoplasmic blebbing and the presence of an amorphous electron-dense material free in the cytoplasm and interior membranes. The enhanced injury caused by the sulphated derivative was apparent, altering cell adhesion and causing cell aggregation. Nuclear modifications such as fragmentation and condensation of chromatin under the nuclear envelope, which showed to be convoluted, suggested the occurrence of cell death by apoptosis.
    Journal of submicroscopic cytology and pathology 11/1997; 29(4):503-9.
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    ABSTRACT: We report for the first time the detection of glycolipids in a lichen. Three glycolipids were extracted from Ramalina celastri and their carbohydrates were determined. The main component was O-alpha-D-galactopyranosyl-(1-->6)-O-beta-D-galactopyranosyl-(1-->1)-D- glyceritol, esterified with long-chain fatty acids, some of which were unsaturated.
    Brazilian Journal of Medical and Biological Research 02/1994; 27(2):523-6. · 1.03 Impact Factor
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    ABSTRACT: The lichen Parmotrema cetratum contains traces of the unusual threitol and unexpected volemitol, along with galactose (2%). Present is a complex containing a lightly branched beta-glucan containing (1-->3) and (1-->4)-linkages in a 25:47 molar ratio chemically linked to a galactomannan with structural features common in other lichens. A glucogalactomannan with a small proportion of Glc rho side chains was also characterized.
    Phytochemistry 10/1993; 34(3):715-7. · 3.35 Impact Factor
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    ABSTRACT: Antimony(Sb)-yeast mannan complexes were synthesized as a strategy to introduce Sb into macrophages infected with Leishmania amastigotes. The complexes were taken up by endocytosis after specific recognition by alpha-D-mannosyl receptors on the macrophage membrane. About 90% of the intracellular parasites were destroyed by Sb-mannan in vitro, whereas the corresponding Sb concentration used as the pentavalent antimonial drug glucantime destroyed about 60% of the amastigotes. None of the Sb complexes prepared with mannan acid or basic derivatives was as effective as the simple Sb-mannan complex in clearing macrophage infection by Leishmania (L) amazonensis. The leishmanicidal effect of Sb-mannan was also demonstrated in vivo with infected hamsters. The alternative use of Sb-mannan complex in the treatment of human leishmaniasis is envisaged on the basis of parasite-killing efficiency and the use of a low antimony dose.
    Biochemical Journal 02/1993; 289 ( Pt 1):155-60. · 4.78 Impact Factor
  • A M Miceno, P A Gorin, M Iacomini
    Agricultural and biological chemistry 06/1991; 55(5):1391-2.
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    ABSTRACT: Antibodies that lyse trypomastigotes in a complement-mediated reaction are believed to be the main participants in the protection against virulent Trypanosoma cruzi. Antibodies with a specificity for alpha-galactosyl-containing determinants--generally called antiGal--were studied to determine their role in the lysis of trypomastigote forms. The titers of antiGal markedly increase in Chagas's disease. In the present study we demonstrate binding of this antibody to T. cruzi and the complement-mediated lysis of trypomastigotes by antiGal. Lysis of metacyclic trypomastigotes by whole Chagasic (Ch) serum or isolated antiGal fractions was equally inhibited by alpha- but not by beta-galactosides. Most of the lytic power of the Ch antiGal as well as of the whole Ch serum was removed by absorption on Synsorb-linked Gal alpha 1, 3Gal beta 1, 4GlcNAc followed by rabbit erythrocyte absorption. The Ch antiGal had a lower affinity for melibiose bound to agarose than for the trisaccharide linked to Synsorb, and was several times more effective in the immunolysis of trypomastigotes than the corresponding antiGal from normal human serum. Lytic antibodies were partly absorbed by Serratia marcescens but not by Escherichia coli O111. A human volunteer immunized with an S. marcescens vaccine elicited a specific antiGal response that was lytic to trypomastigotes (70% lysis). We suggest that in vivo high-affinity antiGal antibody clones, as occur in Ch patients, may significantly contribute to the destruction of the parasite, whereas low-affinity antiGal clones are much less effective in the protection against T. cruzi infection.
    The Journal of Immunology 05/1991; 146(7):2394-400. · 5.36 Impact Factor
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    ABSTRACT: The lipopeptidophosphoglycan of epimastigote forms of Trypanosoma cruzi is composed of a glycan linked through a non-N-acetylated glucosamine residue to an inositol phosphorylceramide. Using conventional analysis techniques, including 1H, 13C, and 31P NMR spectroscopy and negative ion fast atom bombardment mass spectroscopy, the structure of the carbohydrate-containing part of the molecule is determined as: (Sequence: see text). There is uncertainty as to which 2-O-substituted alpha-D-Manp unit is attached the side chain or whether it is distributed between the two units. Some of the structures lack the Galf side chain. The inositol unit is linked to ceramide via a phosphodiester bridge. The major aliphatic components of the ceramide portion were lignoceric acid and sphinganine.
    Journal of Biological Chemistry 03/1990; 265(5):2518-26. · 4.60 Impact Factor
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    ABSTRACT: Fractions were prepared from the water-soluble components ofAspergillus fumigatus mycelium either by lectin-affinity chromatography or salt precipitation. While they varied considerably in their amino-acid composition, each contained a preponderance of aspartic and glutamic acids.13C-NMR spectroscopy of these fractions, compared with that of polysaccharide obtained by alkaline extraction, indicated the presence of glycoproteins, the polysaccharide components of which contained -d-Galf units that are part of structures chemically different from those obtained by alkali treatment. In two of the three fractions examined, gas-liquid chromatography-mass spectrometry showed marked differences in the contents of non-reducing end-units of -d-Manp and -d-Galf. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the preparations revealed an array of components, which stained to differing extents with silver stain and with Coomassie Blue and many of which were bound by lectins with specificity for different sugars.
    Glycoconjugate Journal 02/1989; 6(1):85-100. · 1.95 Impact Factor
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    Memórias do Instituto Oswaldo Cruz 12/1988; 83 Suppl 1:427-30. · 1.57 Impact Factor
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    ABSTRACT: Aqueous and phenolic extracts of Trypanosoma conorhini were fractionated and high molecular weight, carbohydrate-rich fractions obtained. Their antigenic characteristics, reactivity with lectins and partial chemical structure were determined. The major component, the phenolic extract, was electrophoretically diffuse and consisted of 15% protein, 5% phosphorus, hexosamine, and 67% neutral carbohydrate, which contained mannose, galactose, and xylose in a molar ratio of 1.0:1.8:1.8. Chemical analyses and lectin agglutination experiments showed nonreducing end-groups of beta-D-galactopyranose, beta-xylopyranose, and alpha-D-mannopyranose. Phosphate esters occurred, apparently, at O-6 of hexopyranosyl units. Hexosamine was present as nonacetylated units of 2-amino-2-deoxy-alpha-D-glucopyranosyl units that were extremely resistant to acid hydrolysis. On double immunodiffusion tests, the major component gave a precipitation line with rabbit serum against whole cells of Trypanosoma cruzi, suggesting the presence of common antigenic determinant(s) on the cell surface of each trypanosomatid.
    Molecular and Biochemical Parasitology 12/1987; 26(1-2):193-202. · 2.24 Impact Factor
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    ABSTRACT: Epimastigotes of Trypanosoma mega were submitted to phenol extraction after lipid extraction, providing an extract whose carbohydrate portion (30%) contained fucose, ribose, xylose, mannose, galactose, and glucose. The purified fraction recovered in the void volume of Bio Gel P-150 gave on SDS-PAGE a band of Mr approximately equal to 55,000 positive for protein and carbohydrate and a diffuse band strongly positive for carbohydrate and lipids (Mr approximately equal to 22,000). The structural analysis of the carbohydrate moiety of this fraction by GLC-MS indicated the presence of nonreducing end groups of fucopyranose, mannopyranose, and galactopyranose, 3-O- and 4-O-substituted and 2,3- and 2,4-di-O-substituted galactopyranosyl units. Extraction of this fraction with chloroform/methanol/water provided a soluble fraction that on SDS-PAGE gave rise to a carbohydrate and lipid-positive band (Mr approximately equal to 22,000). This fraction contained fucose, mannose, and galactose (1:1:1). As main branch points, 2,3-di-O-substituted galactopyranosyl units were present according to methylation data. Similar proportions of fucopyranosyl, mannopyranosyl, galactopyranosyl end units were present. The presence of lipids in this fraction was confirmed by methanolysis following isolation and characterization of the corresponding fatty acid methyl esters. Palmitic acid (16:0) and an 18:1 fatty acid were the predominant fatty acids.
    The Journal of protozoology 09/1987; 34(3):298-302.
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    ABSTRACT: 1. Aqueous phenol treatment of water extracted disrupted cells of Leishmania tarentolae (LV-414) provided a glycoprotein mixture which was purified by gel filtration chromatography, and Concanavalin A-Sepharose column. 2. The bound fraction on Concanavalin A-Sepharose column (protein 74%, and carbohydrate, 26%) had [alpha]D + 9 degrees and contained mannose (18%), galactose (60%), and glucose (22%), and some of the galactose residues were resistant to periodate oxidation. 3. Treatment of the phenol extract with hot aqueous NaBH4 containing NaOH gave a preparation having mannose (12%), galactose (82%), and glucose (6%). 4. Methylation analysis showed the presence of a mainly linear structure with non-reducing end-units of mannopyranose (6%), 3-O-substituted galactopyranosyl (64%), 2-O- (11%), and 6-O- (5%) substituted mannopyranosyl, and 4-O- (9%), and 4,6-di-O- (3%) substituted glycopyranosyl units. 5. The specific rotation of the preparation, +20 degrees, indicated beta-linked galactopyranosyl units.
    Comparative biochemistry and physiology. B, Comparative biochemistry 02/1987; 88(1):101-4. · 2.07 Impact Factor

Publication Stats

808 Citations
120.35 Total Impact Points


  • 1987–2001
    • Universidade Federal do Paraná
      • Departamento de Bioquímica
      Curitiba, Estado do Parana, Brazil
  • 1990
    • Federal University of Rio de Janeiro
      • Departamento de Microbiologia Geral
      Rio de Janeiro, Rio de Janeiro, Brazil
  • 1986
    • For the Children Brazil
      Miami Beach, Florida, United States
  • 1985
    • National Research Council Canada
      • Plant Biotechnology Institute (PBI)
      Ottawa, Ontario, Canada