ABSTRACT
This polymer has been shown to be produced by a variety of organisms, including fungi, algae (laminarin), bacteria (curdlan), and plants (callose). In fungi, it is a key component of the cell walls of most families, including medically important fungi such as Candida and Aspergillus, but not Zygomycetes. It is also one of the major components of the cyst wall of Pneumocystics carini (Yasuoka et al., 1986). In some fungal species, it can comprise more than 50% of the cell wall dry weight, although this is highly variable (Fleet and Manners, 1976; Nguyen et al., 1998). It is one of a group of beta-linked polysaccharides that play important roles in the mechanical strength and rigidity of fungi cell walls (Cabib et al., 1988; Kollar et al.,1997). In plants, BG is observed to be synthesized in the apical meristem, in specialized vascular connections called plasmodesmata, in wound response tissue synthesis (Jacobs et al., 2003), and in specialized structures in seeds (Yim and Bradford, 1998). Commercial exploitation of BG of alginic origin (Laminarin) for industrial applications, and BG of bacterial origin (curdlan) as an additive in the processed food industry, are well established (Spicer et al., 1999). Numerous medical applications have been proposed, and developed, for BGs. Among these, antitumor applications have been a particularly strong focus, especially in Japan (Ohno et al., 1986a, 1986b, 1986c). Other applications of BGs include the stimulation of general immunity and immuno-protective effects (Hong et al., 2003; Brown and Gordon, 2003; Li et al., 2004) and wound healing (Wei et al., 2002). The relationship between BG structure and immunomodulatory activity has been reviewed (Yadomae and Ohno, 1996; Brown and Gordon, 2003).
