Christine Streb

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ECOTOX is an automatic early warning system to monitor potential pollution of freshwater, municipal or industrial waste waters or aquatic ecosystems. It is based on a real time image analysis of the motility and orientation parameters of the unicellular, photosynthetic flagellate Euglena gracilis. In order to widen the use of the device to marine habitats(More)
The motile, unicellular freshwater flagellate Euglena gracilis uses external stimuli, like gravity, light or oxygen pressure in order to orient itself in its natural habitat. In the darkness the cells normally show a negative gravitactic behavior, that means they swim upward in the water column, Many ground and space experiment revealed that gravitaxis is(More)
Recently it was shown that the unicellular flagellate Euglena gracilis changes the sign of gravitaxis from negative to positive upon excessive radiation. This sign change persists in a cell culture for hours even if subsequently transferred to dim light. To test the ecological relevance of this behavior, a vertical column experiment was performed (max.(More)
In the absence of other external stimuli the motile, unicellular freshwater flagellate Euglena gracilis normally swims upward in the water column (negative gravitaxis). This behavior is most likely triggered by active physiological orientation mechanisms. Recently it was found that negative gravitaxis often inverts to a positive one upon high light(More)
To meet the todays needs for the protection of the environment from pollution through cumulative poisonings or biohazards ecotoxicology uses biotests, to determine effects of chemicals and sewage waters to ecosystems. ECOTOX is a biotest system that allows both the estimation of risks arising from certain substances or substance mixtures as well as the(More)
The unicellular freshwater flagellate Euglena gracilis regulates its position in the water column by means of phototactic and gravitactic behavior. Recent experiments have revealed that the cells switch between negative and positive gravitaxis depending upon environmental stimuli such as solar radiation. In this study, the effect of increased salinity on(More)
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