Availability of Guanitoxin in Water Samples Containing <em>Sphaerospermopsis torques-reginae</em> Cells Submitted to Dissolution Tests

Abstract

Guanitoxin (GNT) is a potent neurotoxin produced by freshwater cyanobacteria that can cause the deaths of wild and domestic animals. Through reports of animal intoxication by cyanobacteria cells that produce GNT, this study aimed to investigate the bio-accessibility of GNT in simulated solutions of the gastrointestinal content in order to understand the process of toxicosis promoted by GNT in vivo. Dissolution tests were conducted with a mixture of Sphaerospermopsis torques-reginae (Cyanobacteria; Nostocales) cultures (30%) and gastrointestinal solutions with and without proteolytic enzymes (70%) at a temperature of 37 °C and rotation at 100 rpm for 2 h. The identification of GNT was performed by LC-QqQ-MS/MS through the transitions [M + H]+m/z 253 > 58 and [M + H]+m/z 253 > 159, which showed high concentrations of GNT in simulated gastric fluid solutions (p-value p-value p-value < 0.05). Therefore, the bio-accessibility of the toxin must be considered both in the stomach and in the intestine, and may help in the diagnosis and prediction of exposure and risk in vivo through the oral ingestion of GNT-producing cyanobacteria cells.

Keywords

• anatoxin-a(s)
• neurotoxins
• cyanobacteria poisoning
• bio-accessibility