Mechanistic approaches for evaluating the toxicity of reactive organochlorines and epoxides in green algae

  title={Mechanistic approaches for evaluating the toxicity of reactive organochlorines and epoxides in green algae},
  author={Christian Niederer and Renata Behra and Angela Harder and René P. Schwarzenbach and Beate I. Escher},
  journal={Environmental Toxicology and Chemistry},
Reactive electrophilic chemicals, such as reactive organochlorine compounds or epoxides, react specifically with a broad spectrum of nucleophilic biomolecules, including proteins and DNA. Conventional toxicity tests for algae, involving the observation of growth inhibition, i.e., the inhibition of cell multiplication, after several days, yield unreliable information for risk assessment because reactive compounds hydrolyze to different extents during the exposure period. The diversity of their… 

Epoxide and thiirane toxicity in vitro with the ciliates Tetrahymena pyriformis: structural alerts indicating excess toxicity.

The derived baseline narcosis model served to evaluate toxicity enhancements T(e) as ratios of narcosis-predicted over experimental EC(50) values, which enabled an in silico screening of epoxides and thiiranes for their potential to exert excess toxicity.

Acute and chronic toxicity toward the bacteria Vibrio fischeri of organic narcotics and epoxides: structural alerts for epoxide excess toxicity.

Surprisingly, 30-min bioluminescence appears to be slightly more sensitive to chemical stress than 24-h growth, which holds both for baseline narcotics and for most of the epoxides, demonstrating that chronic toxicity is not always more sensitive than acute toxicity.

Analyzing cytotoxic effects of selected isothiazol-3-one biocides using the toxic ratio concept and structure-activity relationship considerations.

Analyzing and comparing results using the toxic ratio concept and with data that indicate a dramatic depletion of cellular glutathione levels after incubation with DCOIT reveals that for highly hydrophobic substances, baseline level toxicity in an assay for acute toxicity can lead to an oversight of other more specific modes of toxic action that may cause significant effects that might be less reversible than those caused by unreactive baseline toxicants.

Effect of the structural factors of organic compounds on the acute toxicity toward Daphnia magna

A molecular design (modification) of highly toxic compounds was performed in order to reduce their hazard and acceptable classification QSAR models were developed to reliably predict the following mode of action (MOA): specific and non-specific toxicity of organic compounds towards D. magna.

Screening test battery for pharmaceuticals in urine and wastewater

Results of preliminary experiments with raw and treated urine and wastewater indicate the suitability of the proposed test battery for screening urine and sewage treatment, optimized for universality rather than for specificity.

Phytochelatin induction, cadmium accumulation, and algal sensitivity to free cadmium ion in Scenedesmus vacuolatus

Intacellular cadmium concentration and thiol (glutathione, γ‐glutamylcysteine [γGluCys], and phytochelatins [PCn]) content were determined in the freshwater green alga Scenedesmus vacuolatus exposed to growth‐inhibitory and non inhibitory concentrations of free Cd2+ in the range from 10−14 to 10−7 M.

Mutations of Toluene-4-Monooxygenase That Alter Regiospecificity of Indole Oxidation and Lead to Production of Novel Indigoid Pigments

Modification of the tmoA active site can change the products produced by the enzyme and lead to the production of novel pigments and other indole oxidation products with potential commercial and medicinal utility.



Narcosis due to environmental pollutants in aquatic organisms: residue-based toxicity, mechanisms, and membrane burdens.

In the present review, the toxicity of narcotic chemicals to aquatic organisms is discussed, the possible mechanisms underlying narcosis are reviewed, and a comparison is made between membrane burdens that are lethal in vivo and membranes burdens that cause an effect in in vitro systems.

Chlorophyll a fluorescence: a tool for the investigation of toxic effects in the photosynthetic apparatus.

The effects of environmental pollutants and the photosynthesis of green algae were investigated by using detailed analysis of chlorophyll a fluorescence, suggesting an inhibition of utilization of proton-motive force for ATP synthesis.

Glutathione: toxicological implications.

  • D. J. Reed
  • Biology
    Annual review of pharmacology and toxicology
  • 1990
The role of mitochondrial glutathione in cellular response to toxic exposures that include loss of the homeostases of Ca2+ and protein thiols is described.

Glutathione depletion: its effects on other antioxidant systems and hepatocellular damage.

Experiments carried out with vitamin E-deficient or supplemented diets indicated that pathological phenomena occurring as a consequence of GSH depletion depend on hepatic levels of vitamin E, which may largely modulate the expression of toxicity by GSH-depleting agents.

Glutathione Metabolic Genes Coordinately Respond to Heavy Metals and Jasmonic Acid in Arabidopsis

Feeding experiments suggested that neither oxidative stress, as results from exposure to H2O2, nor oxidized or reduced glutathione levels were responsible for activating transcription of these genes, but Jasmonic acid treatment increased mRNA levels and the capacity forglutathione synthesis but did not alter the glutATHione content in unstressed plants, which supports the idea that the glutathion concentration is controlled at multiple levels.

Pyrene-induced changes of glutathione-S-transferase activities in different microalgal species.

Glutathione and detoxification.

Responses of glutathione cycle enzymes and glutathione metabolism to copper stress in Scenedesmus bijugatus.

  • N. NagalakshmiM. Prasad
  • Biology, Chemistry
    Plant science : an international journal of experimental plant biology
  • 2001

New type of dual-channel PAM chlorophyll fluorometer for highly sensitive water toxicity biotests

A new type of dual-channel PAM chlorophyll fluorometer has been developed, which is specialised in the detection of extremely small differences in photosynthetic activity in algae or thylakoids suspensions, and provides an ultrasensitive biotest system for detection of toxic substances in water samples.

Classifying environmental pollutants