[Structure and biological activities of fungal beta-1,3-glucans].

This paper summarizes the structure, biological activities, signaling, and metabolic degradation of fungal beta-1,3-glucans. Fungal beta-glucans exist both soluble and particulate forms. Conformation of the soluble beta-glucan was classified into three groups: triple helix, single helix and random coil. Fungal beta-1,3-glucans exhibit a variety of biological and immuno-pharmacological activities, and the significance of these activities is dependent on the structure, such as solubility in water, molecular weight, degree of branching, and conformation. Many of the activities, such as nitrogen oxide synthesis of macrophage and limulus factor G activation, were dependent on the conformation, but some of the others were independent, such as interferon-gamma and colony stimulating factor syntheses. These activities are beneficial and pharmacologically useful, while some strongly related to allergic and inflammatory adverse reactions. It should be noted that the beta-glucans, once administered into the body, remain mainly in the liver and spleen for a very long period of time. The activity, at least in part, is maintained during these periods. The biochemical mechanisms of the beta-glucan, especially in soluble form, mediating biological activity was still not clearly demonstrated.