Alterações nas reservas de sementes de Dalbergia nigra ((Vell.) Fr. All. ex Benth.) durante a hidratação

Seed imbibitions is the first stage of the germination process and is characterized by the hydration of tissues and cells and the activation and/or induction of the enzymes responsible for mobilizing reserves for respiration and the construction of new cell structures. The objective of this study was to investigate the alterations in reserve substances during slow hydration of Bahia Rosewood (Dalbergia nigra) seeds in water. Seeds from two different lots (Lot I and II) were placed in saturated desiccators (95-99% RH) to hydrate at 15 and 25 °C until water contents of 10, 15, 20 and 25% were reached. At each level of hydration, changes in lipid reserves, soluble carbohydrates, starch and soluble proteins were evaluated. The mobilization of reserves was similarly assessed in both lots, with no differences being observed between the two hydration temperatures. Lipid contents showed little variation during hydration, while the contents of soluble carbohydrates and starch decreased after the 15% water content level. Soluble proteins showed a gradual tendency to decrease between the control (dry seeds) up to 25% water content

Synthesis of fructans by fructosyltransferase from the tuberous roots of Viguiera discolor (Asteraceae)

Sucrose:sucrose fructosyltransferase (SST) and fructan:fructan fructosyl-transferase (FFT) activities from crude extracts of tuberous roots of Viguiera discolor growing in a preserved area of cerrado were analyzed in 1995-1996. SST activity was characterized by the synthesis of 1-kestose from sucrose and FFT activity by the production of nystose from 1-kestose. The highest fructan-synthesizing activity was observed during early dormancy (autumn), when both (SST and FFT) activities were high. The increase in synthetic activity seemed to start during the fruiting phase in the summer, when SST activity was higher than in spring. During winter and at the beginning of sprouting, both activities declined. The in vitro synthesis of high molecular mass fructans from sucrose by enzymatic preparations from tuberous roots collected in summer showed that long incubations of up to 288 h produced consistently longer polymers which resembled those found in vivo with respect to chromatographic profiles

Synthesis of fructans by fructosyltransferase from the tuberous roots of Viguiera discolor (Asteraceae)

Sucrose:sucrose fructosyltransferase (SST) and fructan:fructan fructosyl-transferase (FFT) activities from crude extracts of tuberous roots of Viguiera discolor growing in a preserved area of cerrado were analyzed in 1995-1996. SST activity was characterized by the synthesis of 1-kestose from sucrose and FFT activity by the production of nystose from 1-kestose. The highest fructan-synthesizing activity was observed during early dormancy (autumn), when both (SST and FFT) activities were high. The increase in synthetic activity seemed to start during the fruiting phase in the summer, when SST activity was higher than in spring. During winter and at the beginning of sprouting, both activities declined. The in vitro synthesis of high molecular mass fructans from sucrose by enzymatic preparations from tuberous roots collected in summer showed that long incubations of up to 288 h produced consistently longer polymers which resembled those found in vivo with respect to chromatographic profiles

Endo-β-mannanase From The Endosperm Of Seeds Of Sesbania Virgata (cav.) Pers. (leguminosae): Purification, Characterisation And Its Dual Role In Germination And Early Seedling Growth

Galactomannans are storage cell wall polysaccharides present in seeds of some legumes. Their degradation is carried out by three hydrolases (α-galactosidase (EC 3.2.1.22), endo-β-mannanase (EC 3.2.1.78) and β-mannosidase (EC 3.2.1.25)). In the present study we purified and characterised an endo-β-mannanase from seeds of Sesbania virgata and addressed its role in germination and seedling development. The polypeptide purified by Ion Exchange Chromatography and Affinity Chromatography on Sepharose-Concanavalin A, showed a pH optimum between 3.5 and 5 at 45°C and high stability at pH 7.8. The low stability at pH 5 appears to be associated with isoelectric precipitation, in view of the pI of the enzyme being 4.5. The purified enzyme is a glycoprotein with a molecular mass of 26 KDa by SDS-PAGE and 36 KDa by gel chromatography. The purified polypeptide attacked galactomannan from different sources, being more effective on polymers with a lower degree of galactosylation (from carob gum), in comparison with medium or highly galactosylated galactomannans (from guar, S. virgata and fenugreek), respectively. A peak of endo-β-mannanase activity was detected during radicle protrusion in the endosperm tissue surrounding the radicle and later on in the lateral endosperm. This second peak was associated with the period of reserve mobilisation. Using an antibody raised against coffee endo-β-mannanase, the enzyme could be detected in immunodot-blots performed with extracts of S. virgata endosperms. The results are consistent with the hypothesis that the peak of endo-mannanase during germination facilitates radicle protrusion through the surrounding endosperm by weakening it in the region close to the radicle tip.182269280Bradford, M.M., A rapid and sensitive method for the quantification of microgram quantities of protein utilizing the principle of protein-dye binding (1976) Anal. Biochem., 72, pp. 248-254Buckeridge, M.S., Dietrich, S.M.C., Galactomannan from Brazilian legume seeds (1990) Rev. Brasil. Bot., 13, pp. 109-112Buckeridge, M.S., Dietrich, S.M.C., Mobilisation of the raffinose family oligosaccharides and galactomannan in germinating seeds of Sesbania marginata Benth (Leguminosae-Faboideae) (1996) Plant Sci., 117, pp. 33-43Buckeridge, M.S., Dietrich, S.M.C., Lima, D.U., Galactomannans as the reserve carbohydrate of legume seeds (2000) Developments in Crop Science, 26, pp. 283-316. , Gupta A.K., Kaur N. (eds), Elsevier Science B. V., AmsterdamBuckeridge, M.S., Santos, H.P., Tiné, M.A.S., Mobilisation of storage cell wall polysaccharides in seeds (2000) Plant Physiol. Biochem., 38, pp. 141-156Dea, I.C.M., Morrinson, A., Chemistry and interactions of seed galactomannans (1975) Adv. Charbohydr. Chem. Biochem., 31, pp. 241-312Dion, A.S., Pometi, A.A., Ammoniacal silver staining of proteins: Mechanisms of glutaraldehyde enhancement (1983) Anal. Biochem., 129, pp. 490-496Downie, B., Hilhorst, H.W.M., Bewley, J.D., A new assay for quantifying endo-β-mannanase activity using Congo Red dye (1994) Phytochemistry, 36, pp. 829-835Dulson, J., Bewley, J.D., Johnson, R.H., Abscisic acid is an endogenous inhibitor in the regulation of mannanase production by isolated lettuce endosperms (1988) Plant Physiol., 87, pp. 660-665Groot, S.P.C., Karssen, C.M., Gibberellins regulate seed-germination in tomato by endosperm weakening: A study with gibberellin-deficient mutants (1987) Planta, 171, pp. 525-531Groot, S.P.C., Karssen, C.M., Dormancy and germination of abscisic acid-deficient tomato seeds: Studies with the sitiens mutant (1992) Plant Physiol., 99, pp. 952-958Halmer, P., Bewley, J.D., Mannanase production by the lettuce endosperm: Control by the embryo (1979) Planta, 144, pp. 333-340Kontos, F., Spyropoulos, C.G., Production and secretion of alpha-galactosidase and endo-β-mannanase activity by carob (Ceratonia siliqua L.) in the endosperm protoplast (1995) J. Exp. Bot., 46, pp. 577-583Laemmli, U.K., Cleavage of the structural protein during the assembly of the head of bacteriophage T4 (1970) Nature, 223, pp. 680-685McCleary, B.V., Modes of action of β-D-mannanase enzymes of diverse origin on legume seed galactomannans (1979) Phytochemistry, 18, pp. 757-763McCleary, B.V., Enzymic interactions in the hydrolysis of galactomannan in germinating guar: The role of exo-β-mannanase (1983) Phytochemistry, 22, pp. 649-658McCleary, B.V., Matheson, N.K., Galactomannan structure and β-mannanase and β-mannosidase activity in germinating legume seeds (1975) Phytochemistry, 14, pp. 1187-1194Meier, H., Reid, J.S.G., Morphological aspects of galactomannan formation in the endosperm of Trigonella foenumgraecum L. (Leguminosae) (1977) Planta, 133, pp. 243-248Mo, B., Bewley, J.D., β-mannosidase (Ec 3.2.1.25) activity during and following germination of tomato (Lycopersicon esculentum Mill.) seeds: Purification, cloning and characterisation (2002) Planta, 215, pp. 141-152Nonogaki, H., Gee, O.H., Bradford, K.J., A germination-specific endo-β-mannanase gene is expressed in the micropylar endosperm cap of tomato seeds (2000) Plant Physiol., 123, pp. 1235-1245Nonogaki, H., Matsushima, H., Morohashi, Y., Galactomannan hydrolysing activity develops during priming in the micropylar endosperm tip of tomato seeds (1992) Plant Physiol., 110, pp. 167-172Potomati, A., Buckeridge, M.S., Effect of abscisic acid on the mobilisation of galactomannan and embryo development of Sesbania virgata (Cav.) Pers. (Leguminosae-Faboideae) (2002) Rev. Brasil. Bot., 25, pp. 303-310Reid, J.S.G., Reserve carbohydrate metabolism in germinating seeds of Trigonella foenun-graecum L. (Legum) (1971) Planta, 100, pp. 131-142Reid, J.S.G., Cell wall storage carbohydrates in seeds: Biochemistry of the seeds gums and hemicelluloses (1985) Adv. Bot. Res., 11, pp. 125-155Reid, J.S.G., Davies, C., Endo-β-mannanase, the Leguminous aleurone layer and storage galactomannan in germinating seeds of Trigonella foenum-graecum L. (1977) Planta, 133, pp. 219-222Reid, J.S.G., Meier, H., Chemotaxonomic aspects of the reserve galactomannan in leguminous seeds (1970) Z. Pflanzenphysiol., 62, pp. 89-92Reid, J.S.G., Meier, H., The function of the aleurone layer during galactomannan mobilisation in germinating seeds fenugreek (Trigonella foenum-graecum L.), crimson clover (Trigonella incarnatum L.) and lucerne (Medicago sativa L.): A correlative biochemical and ultrastructural study (1972) Planta, 106, pp. 44-60Reid, J.S.G., Meier, H., Enzyme activities and galactomannan mobilisation in germinating seeds, of fenugreek (Trigonella foenum-graecum L. Leguminosae): Secretion of α-galactosidases and β-mannosidases by aleurone layer (1973) Planta, 112, pp. 301-308Sioufi, A., Percheron, F., Courtois, J.E., Nucleoside-diphosphateoses et metabolism glucidique au cours de la germination chez le fenugrec (1970) Phytochemistry, 9, pp. 991-999Spyropoulos, C.G., Reid, J.S.G., Regulation of α-galactosidase activity and the hydrolysis of galactomannan in the endosperm of the fenugreek (Trigonella foenum-graecum) seed (1985) Planta, 166, pp. 271-275Spyropoulos, C.G., Reid, J.S.G., Water stress and galactomannan breakdown in germinated fenugreek seeds: Stress affects the production and activities in vivo of galactomannan hydrolysing enzymes (1988) Planta, 179, pp. 403-408Still, D.W., Bradford, K.J., Endo-β-mannanase activity from individual tomato endosperm caps and radicle tips in relation to germination rates (1997) Plant Physiol., 113, pp. 21-29Tiné, M.A.S., Lima, D.U., Buckeridge, M.S., Galactose branching modulates the action of cellulase on seed storage xyloglucans (2003) Carbohydr. Polym., 52, pp. 135-141Toorop, P.E., Bewley, J.D., Hilhorst, H.W.M., Endo-β-mannanase isoforms are present in the endosperm and embryo tomato seeds, but not essentially linked to the completion of germination (1996) Planta, 200, pp. 153-15

Characterization Of Storage Cell Wall Polysaccharides From Brazilian Legume Seeds And The Formation Of Aqueous Two-phase Systems

Cell wall storage polysaccharides from Brazilian legume seeds of Dimorphandra mollis, Schizolobium parahybum (galactomannans), Copaifera langsdorffii, Hymenaea courbaril (xyloglucans) and the galactan from cotyledons of the Mediterranean species Lupinus angustifolius were extracted and their apparent molecular masses were determined by high-performance size exclusion chromatography analysis. They were, to a large degree, polydisperse, showing molecular masses that varied from 100 000 to 2 000 000. Polyethylene glycol (PEG, 1500, 4000, 6000 and 8000), sodium citrate and dextran (73 000, 60 000-90 000, 505 000 and 2 000 000) were used for investigating phase formation with the seed polysaccharides. Galactomannans and xyloglucans demonstrated phase formation with sodium citrate concentrations lower than 30%, as well as dextrans and polyethylene glycol, and formed gels in the presence of high concentrations of sodium citrate (above 30%). Galactan did not promote phase formation with any of the reagents used. On the basis of the results obtained, the possibility of using legume seed polysaccharides for the partitioning and purification of polysaccharide enzymes in aqueous two-phase systems is suggested.6801-2255261Reid, J.S.G., (1985) Biochemistry of Storage Carbohydrate in Green Plants, pp. 265-288. , Academic Press, LondonBuckeridge, M.S., Dietrich, S.M.D., (1990) Revta. Brasil. Bot., 13, p. 109Reid, J.S.G., Meier, H.A., (1970) Z. Pflanzenphysiol, 62, p. 89Bailey, R.W., (1971) Chemotaxonomy of the Leguminosae, , J.B. Harborne (Editor), DB & BLT, Academic Press, LondonDea, I.C.M., Clark, A.H., McCleary, B.V., (1986) Carbohydr. Res., 147, p. 275Buckeridge, M.S., Reid, J.S.G., (1994) Planta, 192, p. 192Edwards, M., Dea, I.C.M., Bulpin, P.V., Reid, J.S.G., (1985) Planta, 163, p. 133York, W.S., Von Halbeek, H., Darvill, A.G., Albershein, P., (1990) Carbohydr. Res., 200, p. 9Hirst, E.L., Jones, J.K.N., Walder, W., (1947) J. Chem. Soc., p. 1225Kula, M.-R., (1979) Applied Biochemistry and Bioengineering, 2, pp. 71-95. , J. Wingard Jr., L.B.E. Katchalski-Kotzin and L. Goldstein (Editors), Academic Press, New YorkKula, M.-R., (1985) Comprehensive Biotechnology, 2. , C.L. Cooney and A.E. Humphrey (Editors), Pergamon Press, OxfordKula, M.-R., Kroner, K.H., Hustedt, H., Schutte, H., (1981) Ann. NY Acad. Sci., 369, p. 341Kula, M.-R., (1990) Bioseparation, 1, p. 181Aurol, D., (1989), Ph.D. Thesis presented at the Biochemical Engineering Department of the Institut National des Sciences AppliquésAlbertsson, P.A., Tjerneld, F., (1994) Methods Enzymol., 228, p. 3Albertsson, P.-A., Partition of Cell Particles and Macromolecules, p. 1971. , Wiley Interscience, New York, 3rd edZaslavsky, B.Y., Miheeva, L.M., Mesteckina, N.M., Rogozhin, S.V., (1982) J. Chromatogr., 253, p. 149Franco, T.T., Andrews, B.A., Cascone, O., Hodgson, C., Andrews, A.T., Asenjo, J.A., (1990) Separations for Biotechnology, 2. , D.L. Pyle (Editor), SCI, Elsevier, LondonFranco, T.T., Andrews, A.T., Asenjo, J.A., (1995) Biotech. Bioeng., 49. , in pressFranco, T.T., Andrews, A.T., Asenjo, J.A., (1995) Biotech. Bioeng., 49. , in pressKroner, K.H., Hustedt, H., Kula, M.-R., (1982) Biotech. Bioeng., 24, p. 1015Tjerneld, F., Berner, S., Cajarville, A., Johansson, G., (1986) Enzyme Microb. Technol., 8, p. 417Venancio, A., Teixeira, J.A., (1993) Biotech. Prog., 9, p. 635Garnier, L., Schorsh, C., Doublier, J.-L., (1995) Carbohydr. Polymers,, , in pressDea, I.C.M., Morrison, A., (1975) Advan. Carbohydr. Chem. Biochem., 31, p. 24

Patterns of expression of cell wall related genes in sugarcane

Our search for genes related to cell wall metabolism in the sugarcane expressed sequence tag (SUCEST) database (<A HREF="http://sucest.lbi.dcc.unicamp.br/">http://sucest.lbi.dcc.unicamp.br</A>) resulted in 3,283 reads (1% of the total reads) which were grouped into 459 clusters (potential genes) with an average of 7.1 reads per cluster. To more clearly display our correlation coefficients, we constructed surface maps which we used to investigate the relationship between cell wall genes and the sugarcane tissues libraries from which they came. The only significant correlations that we found between cell wall genes and/or their expression within particular libraries were neutral or synergetic. Genes related to cellulose biosynthesis were from the CesA family, and were found to be the most abundant cell wall related genes in the SUCEST database. We found that the highest number of CesA reads came from the root and stem libraries. The genes with the greatest number of reads were those involved in cell wall hydrolases (e.g. beta-1,3-glucanases, xyloglucan endo-beta-transglycosylase, beta-glucosidase and endo-beta-mannanase). Correlation analyses by surface mapping revealed that the expression of genes related to biosynthesis seems to be associated with the hydrolysis of hemicelluloses, pectin hydrolases being mainly associated with xyloglucan hydrolases. The patterns of cell wall related gene expression in sugarcane based on the number of reads per cluster reflected quite well the expected physiological characteristics of the tissues. This is the first work to provide a general view on plant cell wall metabolism through the expression of related genes in almost all the tissues of a plant at the same time. For example, developing flowers behaved similarly to both meristematic tissues and leaf-root transition zone tissues. Besides providing a basis for future research on the mechanisms of plant development which involve the cell wall, our findings will provide valuable tools for plant engineering in the near future

Hypoglycemic activity of polysaccharide fractions containing ß-glucans from extracts of Rhynchelytrum repens (Willd.) C.E. Hubb., Poaceae

ß-Glucans are soluble fibers with physiological functions, such as interference with absorption of sugars and reduction of serum lipid levels. The objective of the present study was to analyze the distribution of ß-glucans in different tissues of the African grass species Rhynchelytrum repens and also to evaluate their hypoglycemic activity. Leaf blades, sheaths, stems, and young leaves of R. repens were submitted to extraction with 4 M KOH. Analysis of the fractions revealed the presence of arabinose, glucose, xylose, and traces of rhamnose and galactose. The presence of ß-glucan in these fractions was confirmed by hydrolyzing the polymers with endo-ß-glucanase from Bacillus subtilis, followed by HPLC analysis of the characteristic oligosaccharides produced. The 4 M KOH fractions from different tissues were subjected to gel permeation chromatography on Sepharose 4B, with separation of polysaccharides with different degrees of polymerization, the highest molecular mass (above 2000 kDa) being found in young leaves. The molecular mass of the leaf blade polymers was similar (250 kDa) to that of maize coleoptile ß-glucan used for comparison. The 4 M KOH fraction injected into rats with streptozotocin-induced diabetes showed hypoglycemic activity, reducing blood sugar to normal levels for approximately 24 h. This performance was better than that obtained with pure ß-glucan from barley, which decreased blood sugar levels for about 4 h. These results suggest that the activity of ß-glucans from R. repens is responsible for the use of this plant extract as a hypoglycemic drug in folk medicine

Patterns of expression of cell wall related genes in sugarcane

Our search for genes related to cell wall metabolism in the sugarcane expressed sequence tag (SUCEST) database (<A HREF="http://sucest.lbi.dcc.unicamp.br/">http://sucest.lbi.dcc.unicamp.br</A>) resulted in 3,283 reads (1% of the total reads) which were grouped into 459 clusters (potential genes) with an average of 7.1 reads per cluster. To more clearly display our correlation coefficients, we constructed surface maps which we used to investigate the relationship between cell wall genes and the sugarcane tissues libraries from which they came. The only significant correlations that we found between cell wall genes and/or their expression within particular libraries were neutral or synergetic. Genes related to cellulose biosynthesis were from the CesA family, and were found to be the most abundant cell wall related genes in the SUCEST database. We found that the highest number of CesA reads came from the root and stem libraries. The genes with the greatest number of reads were those involved in cell wall hydrolases (e.g. beta-1,3-glucanases, xyloglucan endo-beta-transglycosylase, beta-glucosidase and endo-beta-mannanase). Correlation analyses by surface mapping revealed that the expression of genes related to biosynthesis seems to be associated with the hydrolysis of hemicelluloses, pectin hydrolases being mainly associated with xyloglucan hydrolases. The patterns of cell wall related gene expression in sugarcane based on the number of reads per cluster reflected quite well the expected physiological characteristics of the tissues. This is the first work to provide a general view on plant cell wall metabolism through the expression of related genes in almost all the tissues of a plant at the same time. For example, developing flowers behaved similarly to both meristematic tissues and leaf-root transition zone tissues. Besides providing a basis for future research on the mechanisms of plant development which involve the cell wall, our findings will provide valuable tools for plant engineering in the near future