Production and properties of cyanobacterial endotoxins

Abstract

Lipopolysaccharides (LPS) were isolated from four species of cyanobacteria (Anabaena flos-aquae UTEX 1444. A. cylindrica, Oscillatoria tenuis, and O. brevis) frequently occurring in drinking-water supplies. The cyanobacterial LPS contained glucose, xylose, mannose, and rhamnose, but differed from the LPS derived from most gram-negative bacteria because of the variable presence of 2-keto-3-deoxyoctonate, heptose, galactose, and glucosamine. Cyanobacterial lipid A is characterized by long-chain saturated an unsaturated fatty acids and hydroxy fatty acids which show great diversity. Unlike lipid A from heterotrophic gram-negative bacteria, lipid A from cyanobacteria usually lacks phosphates. The detection of distinct O-antigen chemotypes indicates that LPS may be used for taxonomic classification. Isolated cyanobacterial LPS always induced Limulus amoebocyte lysate gelation. A. flos-aquae LPS gave a positive Schwartzman reaction. Endotoxins from A. cylindrica and O. brevis were toxic to mice when injected intraperitoneally. The cyanobacterial endotoxins showed generally lower biological activity than did LPS derived from common heterotrophic gram-negative bacteria. Nevertheless, cyanobacteria in algal blooms may be a significant source of endotoxins in water supplies.

Allergenic (sensitization, skin and eye irritation) effects of freshwater cyanobacteria—experimental evidence

“…This is the first experimental evidence that axenic cyanobacteria have not caused allergenic effects on albino guinea pigs. Keleti and Sykora (1982) emphasized that the allergenic effect is more likely caused by lipo polysaccharides of cell walls, than the toxin content. Our experiments strengthen this statement but implicate the lipopolysaccharides of contaminant bacterial flora rather than cyanobacterial cell walls.…”

Isolation and endotoxin activities of lipopolysaccharides from cyanobacterial cultures and complex water blooms and comparison with the effects of heterotrophic bacteria and green alga

“…Cyanobacterial LPS have previously been shown to have lower toxicity in vivo than LPS from highly toxic bacteria such as Salmonella sp. that are often lethal for mice and highly pyrogenic in experiments with rabbits (Keleti et al, 1979;Weckesser et al, 1979;Schmidt et al, 1980;Keleti and Sykora, 1982;Raziuddin et al, 1983). Although acute endotoxin toxicities of cyanobacterial LPS may be lower than those Salmonella, several recent reports describe the modulatory effects of LPS on the metabolism and toxicities of other compounds (such as cyanotoxin microcystin) in aquatic organisms (Best et al, 2001(Best et al, , 2002(Best et al, , 2003Pietsch et al, 2001;Lindsay et al, 2006).…”

Cyanobacterial toxins and human health

“…Cyanobacteria produce LPS as an important constituent of the cell wall. Cyanobacterial LPS differs from that of most other bacteria in lacking phosphate in the lipid A core (Keleti and Sykora 1982). In animal experiments cyanobacterial LPS is about 10 times less toxic than enterobacterial LPS (Codd 1984).…”

“…Reports of the effect of the injection of endotoxins in mice give conflicting results. Some studies have shown no effect (Weise et al 1970;Keleti et al 1979) while other have demonstrated lethal effects including positive Schwartzman reactions (Keleti et al 1979;Keleti and Sykora 1982).…”