Colostrum oligosaccharides are known to exhibit prebiotic and immunomodulatory properties. Oligosaccharide composition is species-specific, and equine colostrum has been reported to contain unique oligosaccharides. Therefore, equine oligosaccharides (EMOS) from colostrum from different horse breeds were analyzed by CE-LIF, CE-MS(n), HILIC-MS(n), and exoglycosidase degradation. Sixteen EMOS were characterized and quantified, of which half were neutral and half were acidic. EMOS showed about 63% structural overlap with human milk oligosaccharides, known for their bioactivity. Seven EMOS were not reported before in equine oligosaccharides literature: neutral Gal(β1-4)HexNAc, Gal(β1-4)Hex-Hex, β4'-galactosyllactose, and lactose-N-hexaose, as well as acidic 6'-Sialyl-Hex-Ac-HexNAc, sialyllacto-N-tetraose-a, and disialylacto-N-tetraose (isomer not further specified). In all colostrum samples, the average oligosaccharide concentration ranged from 2.12 to 4.63 g/L; with β 6'and 3'- galactosyllactose, 3'-sialyllactose, and disialyllactose as the most abundant of all oligosaccharides (27-59, 16-37, 1-8, and 1-6%, respectively). Differences in presence and in abundance of specific EMOS were evident not only between the four breeds but also within the breed.

Summary. Self-incompatibility in flowering plants is controlled by the S-gene, encoding stylar S (allele-specific) glycoproteins. In addition to three previously characterized Petunia hybrida S-proteins, we identified by N-terminal sequence analysis another stylar S-protein, cosegregating with the Sb-allele. Purified S-proteins reveal biological activity, as is demonstrated for two of them by the allele-specific inhibition of pollen tube growth in vitro. Moreover, the four isolated S-proteins are ribonucleases (S-RNases). Specific activities vary from 30 ($1) to 1000 (82) units per min per mg protein. We attempted to investigate the functionality of the carbohydrate portion of the S-RNases. Deglycosylation studies with the enzyme peptide-N-glycosidase F (PNGase F) reveals differences in the number of N-linked glycan chains present on the four S-RNases. Variability in the extent of glycosylation accounts for most of the molecular weight differences observed among these proteins. By amino acid sequencing, the positions of two of the three N-glycosylation sites on the S2-RNase could be located near the N-terminus. Enzymic removal of the glycan side chains has no effect on the RNase activity of native S-RNases. This suggests another role of the glycan moiety in the self-incompatibility mechanism.

By means of experiments with Coleus rhenaltianus it could be demonstrated that the effect of proximally as well as of distally applied auxin (IAA) on the abscission of debladed petioles, is an indirect one. By growth processes that are induced by the application of auxin at the proximal side of the abscission zone, e.g. by the development of new adventitious roots and by the elongation of roots that are already present, a substance that retards the abscission is drained off from the petioles. This substance is produced in the petioles, and probably also in the leaf‐blades, when the latter are exposed to the light, and it was found to migrate through the parenchyma. A low concentration of auxin that is distally applied, accelerates the abscission of the petioles, provided that there is growth activity in the part at the proximal side of the abscission zone. The accelerated abscission in horizontally placed plants is due to growth processes that are induced at the lower side of the stem by the gravitational force. The difference in abscission time between the petioles of plants that are kept in the vertical position, and those that are placed horizontal, is independent of distally applied sugar and of the concentration of distally applied auxin. The abscission proves to be retarded when the petioles are debladed a week after the plants had been brought in the horizontal position or when there is no source of auxin proximal of the abscission zone (young leaves). In the horizontal position the gravitational force affects a lateral shift of auxin from the tip to the lower side of the stem, and it hampers moreover the basipetal transport of substances that are produced in the leaf blades, and by which the growth of roots, the growth at the lower side of the stem and the development of new adventitious roots are promoted. By means of paper chromatography it was found that the substance from the petioles which retards the abscission, is most probably identical with an auxin‐like substance that was extracted from full‐grown leaves, and of which it could be shown that it is not an indole derivative. In plants in the normal position the abscission is accelerated by the longitudinal component of gravity. Elimination of the longitudinal component hampers the transport of the substance which retards the abscission, a transport that is directed to centres of growth, and so it can exercise its influence on the petioles themselves, and retard their abscission. The retardation of the abscission in plants that are rotating parallel to the horizontal clinostat axis, is influenced by the revolving speed of this axis. This retardation is greatest at a revolving speed of 1–3 min. In slowly rotating plants the retardation of the abscission is partly compensated by the effect of the transversal component of gravity which promotes the abscission. The effect of the elimination of the longitudinal component is independent of the presence of a proximal source of auxin, e.g. of the tip and of young leaves.

BackgroundDietary supplementation with oligosaccharides has been proven to be beneficial for health in several mammalian species. Next to prebiotic effects resulting in a modulation of gut micro biota, immunomodulatory effects of oligosaccharides have been documented in vivo. Supplementation with defined oligosaccharide fractions has been shown to attenuate allergic responses and enhance defensive immune responses. Despite the accumulating evidence for immunomodulatory effects, very limited information is available regarding the direct mechanism of action of oligosaccharides. This study aims to elucidate the effects of selected oligosaccharide fractions on the lipopolysaccharide (LPS) induced inflammatory response in equine peripheral blood mononuclear cells (PBMCs). We investigated three different products containing either galacto-oligosaccharides (GOS) alone, a combination of GOS with fructo-oligosaccharides (FOS), and a triple combination of GOS and FOS with acidic oligosaccharides (AOS), at different concentrations. These products have been used in an identical composition in various previously published in vivo experiments. As the selected oligosaccharide fractions were derived from natural products, the fractions contained defined amounts of mono- and disaccharides and minor amounts of endotoxin, which was taken into account in the design of the study and the analysis of data. Acquired data were analysed in a Bayesian hierarchical linear regression model, accounting for variation between horses.ResultsExposing cultured PBMCs to either GOS or GOS/FOS fractions resulted in a substantial dose-dependent increase of tumour necrosis factor-α (TNF-α) production in LPS challenged PBMCs. In contrast, incubation with GOS/FOS/AOS resulted in a dose-dependent reduction of both TNF-α and interleukin-10 production following LPS challenge. In addition, incubation with GOS/FOS/AOS significantly increased the apparent PBMC viability, indicating a protective or mitogenic effect. Furthermore, mono- and disaccharide control fractions significantly stimulated the inflammatory response in LPS challenged PBMCs as well, though to a lesser extent than GOS and GOS/FOS fractions.ConclusionsWe found distinct immunomodulating effects of the investigated standardised oligosaccharide fractions, which either stimulated or suppressed the LPS induced inflammatory response in PBMCs. Both scenarios require additional investigation, to elucidate underlying modulatory mechanisms, and to translate this knowledge into the clinical application of oligosaccharide supplements in foals and other neonates.

We report isolation and N-terminal amino acid sequencing of three style glycoproteins, which segregate with three S (self-incompatibility) alleles of Petunia hybrida. The S-glycoproteins were expressed mainly in the upper part of the pistil and showed an increasing concentration during flower development. The glycoproteins were purified by a combination of ConA-Sepharose and cation exchange fast protein liquid chromatography. The amount of S-glycoproteins recovered from style extracts varied from 0.5 to 1.6 micrograms per style, which was 40-60% of the amount recovered by a simplified analytical method. N-terminal amino acid sequences of S1-, S2- and S3-glycoprotein showed homology within the fifteen amino terminal residues. These amino acid sequences were compared with the previously published sequences of S-glycoproteins from Nicotiana alata and Lycopersicon peruvianum.