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Published on: November 16, 2016
Microcystis aeruginosa toxin: cell culture toxicity, hemolysis, and mutagenicity assays
Abstract:
Crude toxin was prepared by lyophilization and extraction of toxic Microcystis aeruginosa from four natural sources and a unicellular laboratory culture. The responses of cultures of liver (Mahlavu and PCL/PRF/5), lung (MRC-5), cervix (HeLa), ovary (CHO-K1), and kidney (BGM, MA-104, and Vero) cell lines to these preparations did not differ significantly from one another, indicating that toxicity was not specific for liver cells. The results of a trypan blue staining test showed that the toxin disrupted cell membrane permeability within a few minutes. Human, mouse, rat, sheep, and Muscovy duck erythrocytes were also lysed within a few minutes. Hemolysis was temperature dependent, and the reaction seemed to follow first-order kinetics. Escherichia coli, Streptococcus faecalis, and Tetrahymena pyriformis were not significantly affected by the toxin. The toxin yielded negative results in Ames/Salmonella mutagenicity assays. Microtiter cell culture, trypan blue, and hemolysis assays for Microcystis toxin are described. The effect of the toxin on mammalian cell cultures was characterized by extensive disintegration of cells and was distinguishable from the effects of E. coli enterotoxin, toxic chemicals, and pesticides. A possible reason for the acute lethal effect of Microcystis toxin, based on cytolytic activity, is discussed.
Insights
Microcystis aeruginosa toxin broadly disrupts cell membranes, causing rapid lysis in various mammalian cells and erythrocytes. This potent cytolytic activity, not specific to liver cells, explains its acute lethal effects.
Area of Science:
- Environmental Microbiology
- Toxicology
- Cell Biology
Background:
- Microcystis aeruginosa is a cyanobacterium known to produce toxins.
- The specific mechanisms and targets of Microcystis toxins require further elucidation.
- Understanding toxin effects is crucial for public health and environmental safety.
Purpose of the Study:
- To characterize the cytolytic activity of Microcystis toxins.
- To determine the cell-type specificity and kinetics of the toxin's effects.
- To differentiate Microcystis toxin effects from other cellular insults.
Main Methods:
- Preparation of crude Microcystis toxin from natural and cultured sources.
- Exposure of diverse mammalian cell lines (liver, lung, cervix, ovary, kidney) to the toxin.
- Assays including trypan blue staining for membrane permeability and hemolysis for erythrocyte lysis.
- Kinetics and mutagenicity studies (Ames test).
Main Results:
- Toxin exhibited broad cytolytic activity, affecting multiple cell lines without liver specificity.
- Rapid disruption of cell membrane permeability and erythrocyte lysis observed.
- Hemolysis demonstrated temperature dependence and first-order kinetics.
- No significant effect on bacteria (E. coli, S. faecalis) or protozoa (T. pyriformis); negative mutagenicity results.
Conclusions:
- Microcystis toxin possesses potent, non-specific cytolytic activity.
- The rapid disruption of cell membranes is a key mechanism for its toxicity.
- The characterized cytolytic effects are distinct from other toxins and chemicals.
