Toxins and other bioactive compounds produced by cyanobacteria in Lake Ladoga

Abstract

Biologically active compounds were detected in water blooms on Lake Ladoga for the first time. Screening for cytotoxicity and for trypsin and acetylcholinesterase inhibitors revealed a degree of inhibitory activity by the water bloom biomass, which indicates the presence of cyanobacterial toxins in Lake Ladoga. High performance liquid chromatography (HPLC) of extracts of selected samples from the lake demonstrated a rather high diversity of bioactive compounds including hepatotoxic cyclic peptides (microcystins), enzyme inhibitors (cytotoxins), and a series of unidentified substances. Thirteen toxins and protease inhibitors were identified by the HPLC. The toxins were most diverse in the most eutrophic southern part of the lake (up to 12 bioactive compounds). Chromatograms showed that planktopeptin BL dominated in most of the samples investigated, except those from Svir Bay, where mcyst-LR prevailed. The results obtained indicate anthropogenic eutrophication of Lake Ladoga and a decrease in water quality. This lake is used as the only source of drinking water for the city of St. Petersburg.

Cyanobacteria and Cyanotoxins: From Impacts on Aquatic Ecosystems and Human Health to Anticarcinogenic Effects

“…In addition, cylindrospermopsin, a cyclic guanidinic alkaloid, is also considered to be a hepatotoxin and is produced by several genera of freshwater cyanobacteria [4]. The mechanisms of cyanobacterial toxicity are diverse, ranging from hepatotoxic, cytotoxics, and neurotoxic effects to the inhibition of protein synthesis [23]. Hepatoxins cause the rupture of the liver structure by hypovolemic shock and an excessive accumulation of blood in the liver.…”

Development of Advanced Capillary Electrophoresis Techniques with UV and Mass Spectrometry Detection for Forensic, Pharmaceutical and Environmental Applications

“…The general mechanisms of hepatotoxin are related to the inhibition of protein synthesis [169]. For example, hepatotoxins can inhibit protein phosphatase enzymes (PP1 and PP2A) within liver cells, resulting in increased liver weight and modified plasma membranes [169]. Hepatotoxins can also cause damage of liver structure by hypovolemic shock and extra accumulation of blood in the liver [170].…”

“…Microcystin is also considered to be a hepatotoxin and is produced by various genera of freshwater cyanobacteria, such as microcystis, anabaena, nostoc, and oscillatoria [167,168]. The general mechanisms of hepatotoxin are related to the inhibition of protein synthesis [169]. For example, hepatotoxins can inhibit protein phosphatase enzymes (PP1 and PP2A) within liver cells, resulting in increased liver weight and modified plasma membranes [169].…”

“…Another accident occurred in Brazil where the poisoning resulted from the blooms of anabaena and microcystin freshwater genera. This poisoning incident led to gastroenteritis in 2,000 people and 88 deaths over a period of 42 days [169].…”

“…Human exposure to low but long-term concentrations of microcystin can cause chronic diseases, such as tumors and cancers, which are related to the toxicity of microcystin. Therefore, the World Health Organization (WHO) established a maximum value of 1 ppb for microcystin-LR in drinking water in 1997 [169,174].…”