Antibodies as probes for the study of location and metabolism of (1→3), (1→4)‐β‐D‐glucans

Abstract

Polyclonal antibodies, raised against ((1→3), (1→4)‐β‐D‐glucans from oat (Avena sativa L.) caryopsis, were used to investigate the location and the metabolism of mixed‐linked β‐D‐glucans. The binding of these antibodies to the cell walls of oat coleoptiles was shown by an indirect fluorescence method. Distinct fluorescent regions were observed along the inner layers of the walls of each cell. The preimmune serum or antibodies pretreated with oat caryopsis β‐D‐glucans did not react with the cell walls. Glucan antibodies were bound to the walls of other Poaceae coleoptiles as well as to those from oat mesocotyls and roots, whereas they were not bound to the walls of some dicotyledons tested. The relative glucan content of the cell walls of oat coleoptiles as determined by β‐D‐glucanase (EC 3.2.1.73) treatment was maximum between day 3 and 4 after soaking, but it declined during further elongation. A rapid decrease in glucan content was observed in excised coleoptiles when auxin or β‐D‐glucanase was present. There was a clear correlation between the glucan content expressed on a basis of cell wall polysaccharides and the amount of the antibodies bound to the cell walls. These results indicate that the antibodies are useful probes to detect and determine (1→3), (1→4)‐β‐D‐glucans of cell walls.