The isolation and characterization of lipopolysaccharides from Microcystis aeruginosa, a prominent toxic water bloom forming cyanobacteria
| Authors | |
|---|---|
| Year of publication | 2013 |
| Type | Article in Periodical |
| Magazine / Source | Toxicon |
| MU Faculty or unit | |
| Citation | |
| Doi | http://dx.doi.org/10.1016/j.toxicon.2013.10.011 |
| Field | Water pollution and control |
| Keywords | Endotoxin; Cyanobacteria; Water bloom; Lipopolysaccharide; Microcystis |
| Description | Massive toxic blooms of cyanobacteria represent a major threat to water supplies worldwide, yet serious gaps exist in understanding their complex toxic effects, including the role of lipopolysaccharides (LPS). The present comparative study focused on the levels and biological activities of LPS isolated from Microcystis aeruginosa, which is one of the most globally distributed toxic species. Using hot phenol extraction, LPS was isolated from 3 laboratory cultures and 11 natural water blooms. It formed 0.2-0.7% of the original dry biomass of the cyanobacteria, based on gravimetry. Additional analyses by commercial anti-LPS ELISA were correlated with gravimetry but showed concentrations that were about 7-times lower, which indicated either impurities in isolated LPS or the poor cross-reactivity of the antibodies used. LPS isolates from M. aeruginosa were potent pyrogens in the traditional Limulus amebocyte lysate (LAL)-test, but comparison with the PyroGene test demonstrated the limited selectivity of LAL with several interferences. The determined pyrogenicity (endotoxin units, EU) ranged from very low values in laboratory cultures (less than 0.003 up to 0.008-EU per 100 pg LPS) to higher values in complex bloom samples (0.01-0.078 EU per 100 pg of LPS), which suggested the role of bloom-associated bacteria in the overall effects. Potent pro-inflammatory effects of the studied LPS from both cultures and bloom samples were observed in a highly-relevant ex vivo human blood model by studying reactive oxygen species production in phagocytes as well as increased productions of interleukin 8, IL-8, and tumor necrosis factor alpha, TNF-alpha. LPS from M aeruginosa seem to modulate several pathways involved in the regulation of both innate immunity and specific responses. |
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