Renewable raw materials. Polysaccharides from seed cell walls; their role in germination. Industrial polysaccharides from seaweeds: carrageenans and fucoidans. Molecular modelling of disaccharides related to seaweed polysaccharides.

 

Project TX-14 granted by the University of Buenos Aires

(part of this project is financed by the National University of Patagonia San Juan Bosco and the CONICET)

 

 

 

Dr. Carlos A. Stortz

 

Dr. Alberto S. Cerezo

Dr. María C. Rodríguez

Pharm. María L. Flores (UNPSJB)

Pharm. N.M. Andrea Ponce

Lic. (B.Sc.) Diego A. Navarro

Mr. Gustavo Suyama

 

 

 

 

Research interests

 

a)           Polysaccharides from seed cell walls. Applications and role in the germination process.

 

The carbohydrates which constitute the cell walls of the endosperm and cotyledons from Legume seeds are being studied. Using extractive and separative techniques, fractions are isolated and purified. Their methylation analyses, spectroscopic studies and degradation pathways provide clues to the structures present in different seeds. The role of these structures in the germination process is then analyzed.

 

b)           Industrial polysaccharides from seaweeds: carrageenans, fucoidans and related polysaccharides.

 

The systems of polysaccharides present in different red and brown seaweeds from the Argentinian shores of the Patagonia are being studied. After the fractionation and purification of those polysaccharides, their  structure is analyzed, as well as the relationship of these structures with their physical (e.g. gelling behavior) and biological properties (antiviral or anticoagulant activities, etc.). On the other hand, the composition and structure of the cell walls of those seaweeds is also studied, using both chemical techniques, as well as microscopical observations. In connection with the studies about brown seaweeds fucoidans, the constituting polysaccharides from marine sponges are also being studied. Besides, the methodology for the accurate analysis of the polysaccharidic components is being developed.

 

c)           Conformational analysis of disaccharides related to carrageenans.

 

The analysis of the spatial arrangement (conformational map) of carrageenan-related disaccharides is being carried out. The influence of sulfate groups is analyzed, using molecular mechanics methods, and correlations with experimental data. These results provide details to explain the physical properties of the polysaccharides, as well as clues about their reactivity. Those studies have been extended to other cyclic compounds, using different computational resources. The development of reproducible and reliable methods for these complex calculations is one of the main purposes of the Project.

 

 

 

Some publications within the last years

 

Legume seed polysaccharides

 

“Cell walls of the cotyledons of three Sophora species”, C.A.Stortz, E.Ancibor and A.S.Cerezo, Phytochemistry, 37 (1994) 317-325.

 

“Carbohydrates of the cotyledons of Lathyrus odoratus L.”, S.B.Colavecchia, M.C. Rodriguez, C.A.Stortz and A.S.Cerezo, An. Asoc. Quim. Argent., 86 (1998) 270-280.

 

 

Seaweed polysaccharides

 

“High-field NMR spectroscopy of cystocarpic and tetrasporic carrageenans from Iridaea undulosa”, C.A.Stortz, B.E.Bacon, R.Cherniak and A.S.Cerezo, Carbohydr.Res., 261 (1994) 317-326.

 

“Red seaweed galactans: methodology for the structural determination of corallinan, a different agaroid”, C.A.Stortz, M.R.Cases and A.S.Cerezo, in Techniques in Glycobiology, R.R.Townsend and A.T. Hotchkiss Jr. (editors), Marcel Dekker, N.York (1997), pp. 567-593

 

“Studies on the skeletal cell wall and cuticle of the cystocarpic stage of the red seaweed Iridaea undulosa Bory”, M.L. Flores, C.A. Stortz, M.C.Rodriguez,  and A.S.Cerezo, Botanica Marina, 40 (1997) 411-419.

 

“The system of agaroids and carrageenans from the soluble fraction of the tetrasporic stage of the red seaweed Iridaea undulosa”, C.A.Stortz, M.R.Cases and A.S.Cerezo, Carbohydr. Polymers, 34 (1997) 61-65.

 

“Antiviral properties of fucoidan fractions from Leathesia difformis”, S.C.Feldman, S.Reynaldi, C.A.Stortz, A.S.Cerezo and E.B.Damonte, Phytomedicine, 6 (1999) 335-340.

 

“Studies on the skeletal cell wall of the cystocarpic stage of the red seaweed Iridaea undulosa B. – Part II – Fractionation of the cell wall and methylation analysis of the inner core-fibrillar polysaccharides”., M.L.Flores, C.A.Stortz  and A.S.Cerezo, Int. J. Biol. Macromol., 27 (2000) 21-27..

 

 

Development of methodology for polysaccharides

 

“Separation and identification of partially ethylated galactoses as their acetylated  aldononitriles and alditols by capillary gas chromatography and mass spectrometry”, M.R.Cases, C.A.Stortz and A.S.Cerezo, J.Chromatogr., 662 (1994) 293-299.

 

“Separation and quantitation of enantiomeric galactoses and their mono-O-methylethers as their diastereomeric 1-deoxy-1-(2'-hydroxypropylamino)-alditols”, M.R.Cases, A.S.Cerezo and C.A.Stortz, Carbohydr.Res., 269 (1995) 333-341.

 

 

Molecular modelling

 

“Use of a general purpose force-field (MM2) for the conformational analysis of the disaccharide a-D-galactopyranosyl-(1®3)-b-D-galactopyranose”, C.A.Stortz and A.S.Cerezo, J.Carbohydr.Chem., 13 (1994) 235-247.

 

“Conformational analysis of sulfated disaccharides using the MM2 force-field”, C.A.Stortz and A.S.Cerezo, An.Asoc.Quim. Argent., 83 (1995) 171-181.

 

 “Conformational analysis of sulfated a-(1®3)-linked d-galactobioses using the MM3 force-field”, C.A.Stortz and A.S.Cerezo, J.Carbohydr.Chem., 17 (1998) 1405-1419.

 

“Full conformational search of monosaccharides using semiempirical and classical methods: application to a-d-galactopyranose”, C.A.Stortz, An.Asoc.Quim.Argent., 86 (1998) 94-103.

 

“A revised structure for (–)-dihydropertusaric acid, a g-butyrolactone acid from the lichen Punctelia microsticta”, M.S.Maier, D.I.González Marimon, C.A.Stortz and M.T.Adler, J.Nat.Products, 62 (1999), 1565-1567.

 

“Disaccharide conformational maps: how adiabatic is an adiabatic map?, C.A.Stortz, Carbohydr. Res., 322 (1999), 77-86.

 

 

 

(modified on March 28, 2000)

 

Mail-to: stortz@qo.fcen.uba.ar