The use of intact luminous photobacteria (Vibrio fischeri or Photobacterium leiognathi) or dinoflagellates for toxicity assessment has some clear advantages that have been scientifically validated. These microorganisms are self-maintained luminescent units that, under proper conditions, emit high and steady levels of luminescence. The intensity of its luminescence is strongly affected by a wide range of contaminants, including pesticides, herbicides, chlorinated hydrocarbons, heavy metals, agents that affect the cell’s integrity, membrane function or cell respiration, or that have an impact on the rate of protein or lipid synthesis. This way, the microorganisms work as biosensors of toxicants and, by comparing the luminescence level obtained in a suspected toxic sample after a short period of incubation, one can detect very low concentrations of a broad range of toxicants. A similar assessment of toxicity would be very difficult or even impossible if all possible contaminants had to be determined separately.
Application Notes related to Water Toxicity Testing
Toxicity assays based on Vibrio fischeri require a sensitive. They are normally performed in tubes but can be easily adapted to microplate format.
Some regulations require the samples to be kept at 15° C. It is normally not necessary to use an instrument with cooling as measurement times are short. It is sufficient to keep the samples simply at that temperature during sample preparation and incubation.