Inter-laboratory trial of a standardized sediment contact test with the aquatic plant Myriophyllum aquaticum (ISO 16191).

A whole-sediment toxicity test with Myriophyllum aquaticum has been developed by the German Federal Institute of Hydrology and standardized within the International Organization for Standardization (ISO; ISO 16191). An international ring-test was performed to evaluate the precision of the test method. Four sediments (artificial, natural) were tested.

Function and regulation of the glutathione peroxidase homologous gene GPXH/GPX5 in Chlamydomonas reinhardtii.

When exposed to strong sunlight, photosynthetic organisms encounter photooxidative stress by the increased production of reactive oxygen species causing harmful damages to proteins and membranes. Consequently, a fast and specific induction of defense mechanisms is required to protect the organism from cell death. In Chlamydomonas reinhardtii, the glutathione peroxidase homologous gene GPXH/GPX5 was shown to be specifically upregulated by singlet oxygen formed during high light conditions presumably to prevent the accumulation of lipid hydroperoxides and membrane damage.

Internal exposure of whitefish (Coregonus lavaretus) to estrogens.

Gonad malformations have been found in fish all over the world. Particularly in Lake Thun (Switzerland) a high prevalence of gonad deformations in whitefish has been observed. Very often, a link between exposure to endocrine disrupting compounds and altered gonad morphology exists.

Zebrafish (Danio rerio) neuromast: promising biological endpoint linking developmental and toxicological studies.

Aquatic toxicology is facing the challenge to assess the impact of complex mixtures of compounds on diverse biological endpoints. So far, ecotoxicology focuses mainly on apical endpoints such as growth, lethality and reproduction, but does not consider sublethal toxic effects that may indirectly cause ecological effects. One such sublethal effect is toxicant-induced impairment of neurosensory functions which will affect important behavioural traits of exposed organisms.

Estrogen receptor subtype beta2 is involved in neuromast development in zebrafish (Danio rerio) larvae.

Estrogens are known to play a role in both reproductive and non-reproductive functions in mammals. Estrogens and their receptors are involved in the development of the central nervous system (brain development, neuronal survival and differentiation) as well as in the development of the peripheral nervous system (sensory-motor behaviors). In order to decipher possible functions of estrogens in early development of the zebrafish sensory system, we investigated the role of estrogen receptor beta(2) (ERbeta(2)) by using a morpholino (MO) approach blocking erbeta(2) RNA translation.

Molecular multi-effect screening of environmental pollutants using the MolDarT.

Molecular effect detection is a useful approach for ecotoxicological screening of chemicals. We show here the application of the molecular DarT (MolDarT), where the expression of selected target genes is detected in short-term (120 h) exposed developing zebrafish (Danio rerio), thus allowing subacute multi-effect compound screening. The genes metallothionein 2 (mt2), cytochrome P450 1A1 (cyp1a1), and recombination activation gene 1 (rag1) are used as endpoints that describe detoxification/metal toxicity (mt2), detoxification/PAH toxicity (cyp1a1), and acquired immune system disruption (rag1).