Purification and chemical characterization of polysaccharides obtained from Lampteromyces japonicus by concanavalin A-sepharose affinity chromatography

Two classes of neutral polysaccharide which could not be separated from each other by conventional methods were isolated from the fungus, Lampteromyces japonicus, by affinity chromatography using concanavalin A-Sepharose. The polysaccharide retained on the concanavalin A-Sepharose column was eluted with 0.05 M methyl α-d-mannopyranoside and appeared to be α-mannan, while that which passed through the column was virtually all β-glucan.Both polysaccharides were subjected to Smith-type degradation, methylation, acetolysis and glucosidase treatment. The results indicated that the α-mannan contained predominantly α-(1 → 2)-linked side chains branching from an α-(1 → 6)-linked backbone at the (1 → 2,6)-linked mannopyranosyl residues. Galactose was attached to approximately one-quarter of the non-reducing mannose terminals. The β-glucan seemed to contain mainly (1 → 6)-linked side chains branching from a (1 → 3)-linked backbone at the (1 → 3,6)-linked glucopyranosyl residues.     

Comparative studies on beta-glucan hydrolases. Isolation and characterization of an exo(1 yields 3)-beta-glucanase from the snail, Helix pomatia.

An exo-β-glucan hydrolase, present in the digestive juice of the snail, Helix pomatia, has been purified to homogeneity by chromatography on Bio-Gel P-60, Sephadex G-200, DEAE-cellulose, and DEAE-Sephadex. The enzyme degrades β-(1 → 3)-linked oligosaccharides and polysaccharides, rapidly and to completion, or near completion, yielding glucose as the major product of enzyme action. Mixed linkage (1→3; 1→4)-β-glucans are also extensively degraded and β-(1→6)- and β-(1→4)-linked glucose polymers are slowly degraded by the enzyme. This enzyme differs from other exo-β-glucanases, reported previously, in the broadness of its substrate specificity. The K_m values for action on laminarin and lichenin are respectively 1.22 and 2.22 mg/ml; the maximum velocity of action on laminarin is approximately twice that on lichenin. The enzyme has a molecular weight of 82,000 as determined by polyacrylamide gel electrophoresis. Maximum activity is exhibited at pH 4.3 and at temperatures of 50–55 °C.     

Smith degradation of gum exudates from some prosopis species

The polysaccharide of P. hymantophora has been shown to be composed of (1→4)-linked galactopyranosyl, (1→3)-linked galactopyranosyl, (1→3)-linked galactopyranosyl 2- and 4-sulphate and 2,6-disulphate residues. The (1→3)- and (1→4)-linked units are present in approximately equal amounts. The polysaccharide of P. hieroglyphica has been shown to possess (1→4)-linked galactopyranosyl, (1→3)-linked galactopyranosyl, and (1→3)-linked galactopyranosyl 2- and 4-sulphate residues. The (1→3)- and (1→4)-linked units are present in a 4:1 ratio. Both polysaccharides contain small proportions of non-reducing xylosyl end-groups.     

Determination of the linkages in some methylated,sialic acid-containing,meningococcal polysaccharides by mass spectrometry

The application of gas-liquid chromatography-mass spectrometric (g.l.c.-m.s.) analysis to a number of sialic acid-containing polysaccharides of meningococcal origin has been studied. Methylation of these polysaccharides by the Hakomori conditions resulted in both O- and N-methylation. Methanolysis of the methylated polysaccharides from serogroup C [(2→9)-linked], colominic acid [(2→8)-linked], and serogroups Y and W-135 [both (1→4)-linked], yielded the respective 4,7,8,4,7,9-, and 7,8,9-tri-O-methyl derivatives of methyl N-acetyl-N-methyl-β-D-neuraminate methyl glycoside. As model compounds, methyl N-acetyl-4,7,8,9-tetra-O-methyl-α-D-neuraminate methyl glycoside and its N-methyl derivative were also synthesized. All of the methylated derivatives could be identified on the basis of their typical fragmentation-patterns, indicating that this method is applicable to the determination of the position of linkages to sialic acid residues in biopolymers.     

Chemical and biological properties of a highly branched β-glucan from edible mushroom Pleurotus sajor-caju

Hot aqueous extraction of the basidiocarps of the mushroom Pleurotus sajor-caju provided a cold water-soluble, gel-like glucan, which was characterized chemically, and its effects on RAW 264.7 cell line (mouse leukaemic monocyte macrophage) activation were determined. NMR spectroscopy, HPSEC, methylation analysis, and a controlled Smith degradation showed it to have a branched structure with a (1→3)-linked β-Glcp main-chain, substituted at O-6 by single-unit β-Glcp side-chains, on the average of two to every third residues of the backbone, with a molar mass of 9.75×10(5)gmol(-1). In macrophage cell culture, the β-glucan induced production of NO and the cytokines TNF-α, IL-1β, these effects being very similar as those of Escherichia coli serotype 0111:B4 Sigma-Aldrich lipopolysaccharide (LPS), although not modifying the response of LPS-activated macrophages. The results suggest that the (1→3), (1→6)-linked β-glucan from P. sajor-caju may have potential for immunological activities, although additional experiments are necessary for a better understanding of the mechanisms involved.     

Synthesis of analogs of a metabolite of sodium 2-pyridinethiolate N-oxide (pyrithione)

Antitumor activities of two (1 → 6)-branched (1 → 3)-β-d-glucans, isolated from the fruiting body of Auricularia auricula-judae (“kikurage”, an edible mushroom), and other branched polysaccharides containing a backbone chain of (1 → 3)-α-d-glucosidic or (1 → 3)-α-d-mannosidic linkages [and their corresponding (1 → 3)-d-glycans, derived by mild, Smith degradation] were compared. Among these polysaccharides, a water-soluble, branched (1 → 3)-β-d-glucan (glucan I) of A. auriculajudae exhibited potent, inhibitory activity against implanted Sarcoma 180 solid tumor in mice. The alkali-insoluble, branched (1 → 3)-β-d-glucan (glucan II), a major constituent of the fruiting body, showed essentially no inhibitory activity. When the latter glucan, having numerous branches attached, was modified by controlled, periodate oxidation, borohydride reduction, and mild, acid hydrolysis, the resulting, water-soluble, degraded glucan, having covalently linked polyhydroxy groups attached at O-6 of the (1 → 3)-linked d-glucosyl residues, exhibited potent antitumor activity. Further investigations using the glucan-polyalcohol indicated that the attachment of the polyhydroxy groups to the (1 → 3)-β-d-glucan backbone may enhance the antitumor potency of the glucan. On the other hand, partial introduction     

Glucomannan and branched (1 → 3)(1 → 6) β-glucan from the aposymbiotically grown Physcia kalbii mycobiont

Cultures of the mycobiont Physcia kalbii were obtained from germinated ascospores and cultivated on Sabouraud-Sucrose-agar medium. Alkaline extraction of freeze-dried mycelia provided a branched (1 → 3),(1 → 6)-β-glucan and a glucomannan, whose chemical structure was determined by monosaccharide composition, methylation, controlled Smith degradation and NMR spectroscopic analysis. The β-glucan had a (1 → 3)-linked β-glucopyranosyl backbone, partially substituted (approx. 50% of the units) at O-6. The side chains were formed by 6-O- (∼82%) and 2,6-O-linked-β-Glcp units, while the non-reducing ends were formed by β-glucopyranosyl residues. The glucomannan had (1 → 6)-linked α-Manp units in the main chain, almost all being substituted at O-2 by α-Manp and α-Glcp units. This glucomannan could be a typical polysaccharide of lichens from the family Physciaceae.     

Optimization of the Extraction Process and Antioxidant Activity of Polysaccharide Extracted from Centipeda minima

The purpose of this study is to optimize the extraction process and study antioxidant activity of Polysaccharide extracted from Centipeda minima. The Box-Behnken design-response surface methodology was adopted to optimize the extraction process of polysaccharides from Centipeda minima. We purified the crude polysaccharides from Centipeda minima, as well as determined the purity, monosaccharide composition, and molecular weight of the purified fraction. Fourier transform infrared spectrometer (FT-IR) and scanning electron microscopy (SEM) were used to analyze the structural features of the polysaccharides. Further, we investigated the antioxidant activities of different fractions of polysaccharides. Consequently, the results showed that the optimum extraction conditions for polysaccharides were: a liquid-solid ratio of 26 mL/g, extraction temperature of 85.5 °C, and extraction time of 2.4 h. Moreover, the yield of polysaccharides measured under these conditions was close to the predicted value. After purification, we obtained four components of Centipeda minima polysaccharides (CMP). The purity, monosaccharide composition, molecular weight, and structural characteristics of CMP were different, but with similar infrared absorption spectra. CMP exhibited a typical infrared absorption characteristic of a polysaccharide. Besides, CMP displayed good antioxidant activity, with potential to scavenge DPPH radical, hydroxyl radical, and superoxide radical. Therefore, this study provides a reference for future research on the structure and biological activity of CMP, and lays a theoretical foundation for food processing and medicinal development of CMP.     

Isolation and characterisation of cell wall polysaccharides from cocoa (Theobroma cacao L.) beans

 Cell wall material (CWM) was prepared from sun-dried cocoa (Theobroma cacao L.) bean cotyledons before and after fermentation. The monosaccharide composition of the CWM was identical for unfermented and fermented beans. Polysaccharides of the CWM were solubilised by sequential extraction with 0.05 M trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid (CDTA), 0.05 M Na₂CO₃, and 1 M, 4 M and 8 M KOH. The non-cellulosic sugar composition for each fraction was similar for unfermented and fermented samples, indicating that fermentation caused no significant modification of the structural features of individual cell wall polysaccharides. Pectic polysaccharides accounted for 60% of the cell wall polysaccharides but only small amounts could be solubilised in solutions of CDTA, Na₂CO₃, and 1 M and 4 M KOH. The bulk of the pectic polysaccharides were solubilised in 8 M KOH and were characterised by a rhamnogalacturonan backbone heavily substituted with side-chains of 5-linked arabinose and 4-linked galactose. Linkage analysis indicated the presence of additional acidic polysaccharides, including a xylogalacturonan and a glucuronoxylan. Cellulose, xyloglucan and a galactoglucomannan accounted for 28%, 8% and 3% of the cell wall polysaccharides, respectively. It is concluded that the types and structural features of cell wall polysaccharides in cocoa beans resemble those found in the parenchymatous tissue of many fruits and vegetables rather than those reported for many seed storage polysaccharides. Received: 29 May 1999 / Accepted: 19 October 1999     

Mammalian-lung galactan

Exopolysaccharides of Agrobacterium tumefaciens and Rhizobium meliloti, containing d-glucose, d-galactose, pyruvic acid, and O-acetyl groups in the approximate proportions 6:1:1:1.5, were analysed by methylation. They were found to contain the following main structural units (all β-glycosidic): chain residues of (1→3)-linked d-glucose (24%), (1→3)-linked d-galactose (15%), (1→4)-linked d-glucose (20%), and (1→6)-linked d-glucose (18%); (1→4,1→6)-linked branching residues of d-glucose (12%), and terminal d-glucose residues substituted at positions 4 and 6 by pyruvate (11%). Uronic acid-containing exopolysaccharides of Rhizobium leguminosarum, R. phaseoli, and R. trifolii contained d-glucose, d-glucuronic acid, d-galactose, pyruvic acid, and O-acetyl groups in the approximate proportions 5:2:1:2:3. Methylation gave identical patterns of methylated sugar components, from which the following structural elements were deduced: chain residues of (1→3)-linked d-glucose substituted at positions 4 and 6 by pyruvate (13%), (1→4)-linked d-glucose (32%), and (1→4)-linked d-glucuronic acid (20%); (1→4,1→6)-linked branching residues of d-galactose and/or d-glucose (13%), and terminal d-glucose and/or d-galactose residues substituted at positions 4 and 6 by pyruvate (13%).     

Compositional Changes in Compost during Composting and Growth of Agaricus bisporus

Samples from conventional compost taken at various stages of composting and mushroom (Agaricus bisporus) growth were analyzed for changes in 80% ethanol and water extracts, monosaccharides in acid hydrolysates of polysaccharides, lignin concentration, and lignin structural features. Variable amounts of extraneous inorganic solids in the form of fine sandy particles were removed by sedimentation of the samples in a carbon tetrachloride-dibromomethane mixture. During composting, about two-thirds of the initial wall polysaccharides were consumed by compost microorganisms, and only 17% of the total polysaccharides were used during mushroom production. The relative lignin content of composts as measured by the acetyl bromide procedure increased, both during composting and mushroom growth, and the chemical structure of lignin was altered by condensation and oxidation reactions.     

Structure of Hemicellulose Isolated from Rice Endosperm Cell Wall : Mode of Linkages and Sequences in Xyloglucan, β-Glucan and Arabinoxylan

A hemicellulosic polysaccharide, which was homogeneous on sedimentation analysis and also on electrophoresis, was isolated from the rice endosperm cell walls by the combination of alkaline extraction, ion exchange chromatography and iodine complex formation. It is composed of arabinose, xylose and glucose (molar ratio, 1.0: 2.0: 5.7) together with a small amount of galactose and rhamnose. Methylation analysis, Smith degradation and fragmentation with cellulase showed that this polysaccharide is composed of three distinct polysaccharide moieties i.e., xyloglucan, β-glucan and arabinoxylan. The xyloglucan consists of β-(1→4)-linked glucan back bone and short side chains of single xylose units or galactosylxylose both attached to C-6 of the glucose residues. The β-glucan contains both (1 →3)-and (1→4)-linkages similarly to the other cereal β-glucans, but differ from them in containing the blocks of (1→3)-linked glucose residues in the chain. The arabinoxylan has a highly branched structure, in which 78% of (1→4)-linked xylose residues have short side chains of arabinose at C-3 position.

On the basis of these findings, the interconnection of these polysaccharide moieties is discussed.     

Polysaccharides of basidiomycetes. Alkali-soluble polysaccharides from the mycelium of white rot fungus <Emphasis Type="Italic">Ganoderma lucidum</Emphasis> (Curt.: Fr.) P. Karst

Two polysaccharides were isolated from submergedly cultured mycelium of the basidiomycete Ganoderma lucidum by extraction with alkali followed by fractionation with Fehling reagent. The polysaccharides were shown to be a linear (1→3)-α-D-glucan and a highly branched xylomannan containing a backbone built up of (1→3)-linked α-D-mannopyranose residues, the majority of which are substituted at O-4 by single β-D-xylopyranose residues or by disaccharide fragments β-D-Manp-(1→3)-β-D-Xylp-(1→. Polysaccharide structures were elucidated by NMR spectroscopy in combination with methylation analysis and periodate oxidation. An interesting feature of the xylomannan is the simultaneous presence of α-D-mannopyranose and β-D-mannopyranose residues, the first forming the backbone, and the second being the non-reducing terminal units of disaccharide side chains.     

Fine structure of (1→3),(1→4)-β-d-glucan from Zea shoot cell-walls

The insoluble material that remains after extraction of Zea shoots with cold buffer was treated successively with 3m LiCl and hot water. The polysaccharides solubilized by these treatments were mostly (1→3),(1→4)-β-d-glucans. The β-d-glucan from the hot-water-soluble fraction was hydrolyzed by Bacillus subtilis (1→3),(1→4)-β-d-glucan 4-glucanohydrolase. The oligosaccharides were characterized by methylation analysis of the enzymic fragments and by methylation analysis of secondary fragments generated by treatment of the isolated oligosaccharides with Streptomyces QM B814 cellulase. The results demonstrate that the native polysaccharide consists mainly of cellotriosyl and cellotetraosyl residues joined by single (1→3) linkages. Evidence is presented to show that certain other glucosyl sequences are also present in the native polysaccharide including (a) two, three, or four contiguous (1→3)-linkages; (b) blocks of more than four (1→4)-linked glucose residues; (c) regions having alternating (1→3)- and (1→4)-linkages.     

Methylation and acetolysis of extracellular D-mannans from yeast

Methylation-fragmentation analyses were conducted on a series of extracellular, yeast α-D-linked mannans representing six different structural types. D-Mannans of low degree of branching were produced by Hansenula capsulata strains and by species related to H. holstii. The former consisted primarily of (1→2)- and (1→6)-linked D-mannosyl residues; the latter, of (1→2)-and (1→3)-linked D-mannosyl residues. Although the remaining structural types were highly branched, each gave distinct methylation-patterns indicative of (1→6)-linked backbones to which are appended non-(1→6)-linked side-chains. Acetolysis studies were correlated with the methylation analyses, and the correlation demonstrated that each branched polymer possesses side chains of heterogeneous length.     

Characterization of nutrient status of Halamphora luciae (Bacillariophyceae) using matrix-assisted ultraviolet laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS)

The effects of N and P depletion on the production and structural characterization of the cellular carbohydrate polymers of the estuarine diatom Halamphora luciae in batch culture were examined using matrix-assisted laser desorption-ionization time-of flight mass spectrometry (MALDI-TOF MS) complemented with monosaccharide composition determination and structural analyses by methylation of aqueous extracted product. The MALDI MS analysis of the cells showed a similar profile in control and N- and P-depleted media, with a displacement to higher molecular weight for cells grown in depleted media. In the monosaccharide analyses, both nutrient depletion and culture ageing led to an increase in glucose content, indicating that MALDI-TOF MS in whole cells was detecting the changes in chrysolaminarin. The maxima for the ions from f/2-P and to a lesser extent in f/2-N were displaced to higher m/z values indicating a higher degree of polymerization (DP). Methylation analysis confirmed the presence of chrysolaminarin, a (1→3)-β-d-glucan with branching in C2 and C6, where the glucan backbone had a substitution every four glucose residues. The (1→3)-β-d-glucan was also detected in the cingule by fluorescence with aniline blue.     

The composition and structural characteristics of polysaccharides of the brown alga Eisenia bicyclis

The present study examines the polysaccharide composition of the brown alga Eisenia bicyclis. The major polysaccharide of E. bicyclis is shown to be sodium alginate (15.8% of the dry defatted alga weight). The yields of laminaran and fucoidan were 1.4% and 1.3% of the dry defatted alga weight, respectively. The alga contains laminaran (1,3;1,6-β-D-glucan) that has a unique structure, a high content of 1,6-linked D-glucose residues (the ratio of 1,3: 1,6 linkage is 1.5: 1), and an unusually high molecular weight (19–27 kDa). The fucoidan fractions isolated from E. bicyclis are sulfated and acetylated heteropolysaccharides that differ in their sulfate content and monosaccharide composition.     

Structural features of two amyloids from the hemi-cellulosic fraction of field-bean (Dolichos lablab) hulls

Two amyloid-type fractions were isolated from field-bean (Dolichos lablab) hulls by 10% alkali extraction followed by acetylation and solvent fractionation. The major, chloroform-insoluble fraction and a minor, chloroform-soluble fraction were found to be homogeneous in sedimentation analysis and molecular-sieve chromatography. The polysaccharides contained xylose and glucose in various proportions. Methylation analysis, periodate oxidation, Smith degradation, oxidation by chromium trioxide, and oligosaccharide studies indicated a new type of structure for the major fraction (glucose:xylose ratio of 1.9:1) in that it had a backbone of (1→4)-linked β-d-glucose residues interspersed with single or multiple residues of (1→4)-linked β-d-xylose, and to which some single d-xylosyl groups are attached through O-6 of d-glucose. In contrast, the minor fraction (glucose:xylose ratio of 1:3.7) had a backbone of (1→4)-linked β-d-xylose interspersed with (1→4)-β-d-glucose and having a side chain of d-xylose, attached through O-6 of d-glucose. The third fraction was found to be a mixture of linear (1→4)-d-glucan and (1→4)-d-xylan.     

Preparation and the antitumor activity in vitro of polysaccharides from Tricholoma matsutake

Tricholoma matsutake is the most valuable mushroom exhibiting a characteristic and delicate flavor as well as several biological activities among the various mushroom species. Extraction procedure and antitumor activity of polysaccharides from Tricholoma matsutake mycelium were studied in this work. Single factor tests and Response Surface Methodology (RSM) based on a three-level three-factor Box-Behnken design were applied to optimize the water extraction conditions. The polysaccharides yields increased when the ratio of water to sample increased from 10:1 to 30:1, extraction time from 1 to 4 h and temperature from 60 to 90°C as invested in single factor tests. To enhance further polysaccharides extraction, the extraction conditions were studied with RSM. The optimum extraction conditions were confirmed as follows:extraction time 4.3 h, the ratio of water to sample 29.2:1, extraction temperature 93.8°C. The extraction rate of polysaccharides under this condition could reach the highest value of 18.43% with one time extraction, and, 21.63% with two times extraction. Furthermore, the polysaccharides presented significant antitumor activity against B16 human melanoma cells in vitro in a dose-dependent manner. At the concentration of 10 mg/ml, the inhibition rate of polysaccharides got 67%.     

A Unique 2-Sulfated ��-Galactan from the Egg Jelly of the Sea Urchin Glyptocidaris crenularis: CONFORMATION FLEXIBILITY VERSUS INDUCTION OF THE SPERM ACROSOME REACTION*

Sulfated polysaccharides from the egg jelly of sea urchins act as species-specific inducers of the sperm acrosome reaction, which is a rare molecular mechanism of carbohydrate-induced signal-transduction event in animal cells. The sea urchin polysaccharides differ in monosaccharide composition (l-fucose or l-galactose), glycosylation, and sulfation sites, but they are always in the α-anomeric configuration. Herein, structural analysis of the polysaccharide from the sea urchin Glyptocidaris crenularis surprisingly revealed a unique sulfated β-d-galactan composed by (3-β-d-Galp-2(OSO₃)-1→3-β-d-Galp-1)_n repeating units. Subsequently, we used the G. crenularis galactan to compare different 2-sulfated polysaccharides as inducers of the acrosome reaction using homologous and heterologous sperm. We also tested the effect of chemically over-sulfated galactans. Intriguingly, the anomeric configuration of the glycosidic linkage rather than the monosaccharide composition (galactose or fucose) is the preferential structural requirement for the effect of these polysaccharides on sea urchin fertilization. Nuclear magnetic resonance and molecular dynamics indicate that sulfated α-galactan or α-fucan have less dynamic structural behavior, exhibiting fewer conformational populations, with an almost exclusive conformational state with glycosidic dihedral angles Φ/Ψ = −102°/131°. The preponderant conformer observed in the sulfated α-galactan or α-fucan is not observed among populations in the β-form despite its more flexible structure in solution. Possibly, a proper spatial arrangement is required for interaction of the sea urchin-sulfated polysaccharides with the specific sperm receptor.The evolution of barriers to inter-specific hybridization is a crucial step in the fertilization of free-spawning marine invertebrates. In sea urchins the molecular recognition between sperm and egg ensures species recognition. The jelly coat surrounding sea urchin eggs is not a simple accessory structure; it is considerably complex on a molecular level and intimately involved in gamete recognition. It contains sulfated polysaccharides, sialoglycans, and peptides.Structural changes in the sulfated polysaccharide from the egg jelly of sea urchins modulate cell-cell recognition and species specificity leading to exocytosis of the acrosomal vesicle, the acrosome reaction. This is a crucial event for the recognition between male and female gametes, leading to the fertilization success, and is also what prevents intercrosses. The sulfated polysaccharide from the egg jelly recognizes its specific receptor present in the sperm. Apart from the sialoglycans that act in synergy with the sulfated polysaccharides, other components of the egg jelly do not possess acrosome reaction-inducing activity (1). The sulfated polysaccharide-mediated mechanism of sperm-egg recognition co-exists with that of bindin and its receptor in the egg (2–4).The sulfated polysaccharides from sea urchin show species-specific structures composed of repetitive units (mono-, tri-, and tetrasaccharides) that differ in the monosaccharide backbone (l-fucose or l-galactose), glycosidic linkage (3- or 4-linked), and sulfation (2- and/or 4-sulfation). However, they are always in the α-enantiomeric configuration (4, 5). Previous studies from our laboratory have demonstrated that sea urchin-sulfated polysaccharides induce the acrosome reaction in a species-specific way. In some cases the sperm from a certain species of sea urchin recognizes the sulfated polysaccharide containing a similar structure from a different species. For example, the egg jelly from Strongylocentrotus franciscanus contains a 2-sulfated, 3-linked α-fucan, but the sperm from this species recognizes a heterologous 2-sulfated, 3-linked α-galactan from Echinometra lucunter (6).We now extended our studies to the sulfated polysaccharides of the sea urchin Glyptocidaris crenularis (7). Surprisingly, we observed that this species contains a unique sulfated β-d-galactan composed of repetitive disaccharide units alternating 2-sulfated and non-sulfated 3-linked units. This polymer is markedly distinct from all other sea urchin-sulfated polysaccharides described so far that are composed of units on α-l-configuration. Furthermore, this sea urchin does not contain sialoglycans, which are commonly found in the echinoderm egg jelly.We used this new sulfated β-galactan to investigate the acrosome reaction in a further molecular detail using homologous and heterologous sperm. We tested three 2-sulfated polysaccharides that differ in their conformation (α or β) and monosaccharide composition (galactose or fucose) as inducers of the sperm acrosome reaction. We aimed to establish the structure versus biological activity of the echinoderm polysaccharides, including structural features at a conformational level.