Triphenyltin induced growth inhibition and antioxidative responses in the green microalga Scenedesmus quadricauda

Jun Xu, Mei Li, Nai Ki MAK, Feng Chen, Yue Jiang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

The toxicity of organotin compounds in the environment is closely related to their uptake by microorganisms and delivery through the food chain. The population at low trophic levels like microalgae plays an important role in this aspect. In this study, the toxic effects of triphenyltin (TPT) on Scenedesmus quadricauda were assessed at the population, cellular and subcellular levels. The alga was exposed to TPT of up to 64 μg l-1 (nearly lethal concentration), but the algal growth was inhibited significantly when TPT was elevated to 8 μg l-1. This growth inhibition was correlated to the presence of oxidative stress as evidenced by the accumulation of malondialdehyde (MDA) and confirmed by fluorescent probing of the intracellular reactive oxygen species (ROS) levels. The imbalanced activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) may lead to an accumulation of intracellular H2O2, which can initiate an oxidative damage to cell components and cause growth inhibition and finally cell death. The detachment of plasma membrane from cell wall, the structural change of chloroplasts as well as the increased number and size of starch granules together with electron-dense deposits in chloroplasts were noticed through electron microscopic examination. It was suggested that mitochondria, chloroplasts and protoplasm might be the direct targets of TPT toxicity. This study confirmed that TPT poisoning on phytoplankton can happen at very low concentrations. There existed different defense mechanisms e.g., antioxidant enzyme activation, starch accumulation and possibly metal sequestration in algal species as the means to resist TPT toxicity.

Original languageEnglish
Pages (from-to)73-80
Number of pages8
JournalEcotoxicology
Volume20
Issue number1
DOIs
Publication statusPublished - Jan 2011

Scopus Subject Areas

  • Toxicology
  • Management, Monitoring, Policy and Law
  • Health, Toxicology and Mutagenesis

User-Defined Keywords

  • Antioxidant enzymes
  • Oxidative stress
  • ROS
  • Ultrastructure

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