1. Effects of microcystins on and toxin degradation byPoterioochromonas sp
- Author
-
Wei Chen, Nanqin Gan, Danyun Ou, and Lirong Song
- Subjects
Cyanobacteria ,Antioxidant ,Microcystins ,Health, Toxicology and Mutagenesis ,medicine.medical_treatment ,Management, Monitoring, Policy and Law ,Biology ,Toxicology ,medicine.disease_cause ,Peptides, Cyclic ,Microbiology ,Superoxide dismutase ,chemistry.chemical_compound ,Microcystis ,polycyclic compounds ,medicine ,Ecotoxicology ,Enzyme Inhibitors ,Chrysophyta ,Superoxide Dismutase ,Toxin ,General Medicine ,Glutathione ,biology.organism_classification ,Up-Regulation ,Biodegradation, Environmental ,chemistry ,biology.protein ,Marine Toxins ,Subculture (biology) - Abstract
A Chrysophyceae species, Poterioochromonas sp., was isolated from Microcystis cultures. This species can efficiently prey on Microcystis and can grow faster phagotrophically than autotrophically. The growth of Poterioochromonas sp. was stimulated in the presence of microcystin-LR and microcystin-RR (in concentrations ranging from 0.1 to 4 mg/L). The growth rate of Poterioochromonas was 4-5 times higher than the control, indicating the toxins serve as growth stimuli for this organism. A subculture of toxin-treated cells, however, showed low cellular viability, suggesting that growth enhancement by microcystins was not a normal process. The antioxidant enzymatic activity of Poterioochromonas sp. was screened for toxicology analysis. Glutathione; malondialdehyde, and superoxide dismutase (SOD) content was up-regulated within,8 h of exposure to microcystin-LR (500 mu g/L). A high level of SOD activity during exposure to the toxin indicated that SOD was involved in decreasing oxidative stress caused by microcystin-LR. Simultaneously with growth, Poterioochromonas was able to degrade microcystin-LR even, at a toxin concentration of 4 mg/L. This putative degradation mechanism in Poterioochromonas is explored further and discussed in this article. Our findings may shed light on understanding the role of Poterioochromonas in the aquatic ecosystem, in particular, as a grazer of toxic cyanobacteria and a biodegrader for microcystins. (c) 2005 Wiley Periodicals, Inc.
- Published
- 2005