Novel oligosaccharides isolated from Fusarium oxysporum L. rapidly induce PAL activity in Rubus cells.

Activation of the phenolic pathway is known to be part of a defense response against cell wall-derived elicitors from pathogens. Many examples of a defense response by increasing the synthesis of phenolic compound against the elicitor were demonstrated in the past, but the elicitor structure has so far been poorly characterized. Our results indicate that a disaccharide fraction containing the following structure: alpha-D-mannopyranosyl (1-->2)alpha/beta-D-glucopyranosyl and alpha-D-mannopyranosyl (1-->x) inositol, isolated from Fusarium oxysporum L.

High performance liquid chromatography and photodiode array detection of ferulic acid in Rubus protoplasts elicited by O-glycans from Fusarium sp. M7-1.

So far only little data have been available concerning the eliciting capacity of well defined glycan molecules isolated from plant pathogens. This study brings new information about changes in plant cells caused by fungal pathogens. Sugar fractions derived from glycoproteins isolated from the fungus Fusarium sp.

Characterization of the binding of alpha-L-Fuc (1-->2)-beta-D-Gal (1-->), a xyloglucan signal, in blackberry protoplasts.

Previous work showed that the fucose-->galactose moiety of the xyloglucan nonasaccharide XXFG is responsable for its biological activity. We used this side chain of XXFG (alpha-L-Fuc (1-->2)-beta-D-Gal (1-->)) in ligand-binding experiments to demonstrate its role as a signal molecule in plant cells. Proteins solubilized from plasma membrane enriched fractions isolated from Rubus fruticosus protoplasts were tested for their ability to bind the side chain of XXFG, using a digoxigenin- or biotin-conjugated neoglycoprotein specific for 2'-fucosyl-lactose in blots and k-ELISA tests.

Two rhamnogalacturonide tetrasaccharides isolated from semi-retted flax fibers are signaling molecules in Rubus fruticosus L. cells.

Water extraction of semi-retted flax (Linum usitatissimum L.) fiber bundles yielded a mixture of pectic oligosaccharides and two acidic rhamnogalacturonide tetrasaccharides that were separated by size-exclusion chromatography. One- and two-dimensional nuclear magnetic resonance studies and fast atom bombardment-mass spectrometry experiments indicated that the two tetrasaccharides have a common primary structure, i.

Membrane binding sites for the human blood group H-type 2 determinant, an inducer of laminarinase activity in protoplasts of Rubus fruticosus L.

The human blood-group determinants H-type 1 (α-L-Fuc-(1 → 2)-β-D-Gal-(1 → 3)β-D-GlcNAc), or type 2 (α-L-Fuc(1 → 2)-β-D-Gal(1 → 4)-β-D-GlcNAc) and their mono- and disaccharidic precursors, have been reported to induce D-glycanase (laminarinase) activity in Rubus cells (Y. Liénart et al. 1990, Plant Science 68, 197-202) and protoplasts (Y.

Isolation from Rubus cell-suspension cultures of a lectin specific for glucosamine oligomers.

A lectin specific for glucosamine oligomers has been purified by chitosan affinity chromatography from cultured cells of Rubus. The lectin, eluted by a glucosamine oligomer of degree of polymerization 4 in the presence of l-α-phosphatidylserine dipalmitoyl, was found by sodium dodecyl sulfate-polyacrylamide gel electroploresis to be homogeneous and to have a molecular weight of 67 kilodaltons; it could best bind the tetrasaccharide, as shown by ligand-blot processing. Data from kinetic-dependent enzyme-linked immunosorbent assays showed that the lectin has two apparent binding sites which better accommodate the tetrasaccharide and the hexasaccharide, respectively, of the glucosamineoligomer series.

β-D-glucan-hydrolase activities in pure cell-wall-enriched fractions from Valerianella olitoria cells.

An effective method for the preparation of purified cell walls from mesophyll cells of Valerianella olitoria has been developed. Cells were isolated by a mechanical procedure only and crude cell walls were prepared from cell homogenates. Crude wall suspensions were fractionated in a discontinuous sucrose gradient and the wall fragments recovered were examined by scanning electron microscopy.