On Wednesday 7 October 2015 Jonathan Nicolas will be receiving his doctorate from Wageningen University & Research with a PhD thesis entitled Innovative mode of action based in vitro assays for detection of marine neurotoxins. In it Nicolas describes a neuron test that detects marine toxins and can replace a painful animal test with mice.
Marine toxins are toxins produced naturally by algae. Shellfish such as mussels that feed on algae, can accumulate these toxins in their bodies. When a human or animal consumes contaminated shellfish, various symptoms of poisoning can occur, such as memory loss, abdominal cramps, diarrhoea or paralysis.
To test whether shellfish are free of such marine toxins, both chemical tests and, in most parts of the world, mice tests are used. In the mice test (which is not used in the Netherlands), an extract of the shellfish is injected into the mouse’s abdominal cavity. If the mouse dies within 24 hours, the shellfish is considered as not suitable for human consumption. In his research, Jonathan Nicolas developed an alternative for this animal-unfriendly mouse test.
Neuronal cell line
Nicolas’s research initially focused on toxins that can cause paralysis, called neurotoxins. Various in vitro tests were developed. Nicolas first had mouse stem cells grown into beating heart cells. The beating heart cells were an effective model to assess neurotoxins (the cells stopped beating), but were not suitable to detect low levels of these toxins in shellfish. The use of a neuronal cell line proved to be more successful and entails examining when the cell stops functioning. This approach worked for both the toxins that cause paralysis and the toxins that cause diarrhoea. At a later stage of his research, Nicolas demonstrated that the neuron test is highly suitable to test shellfish (as well as fish) for the presence of various types of toxins in an animal-friendly manner.
Combination of in vitro and chemical testing
Nicolas conducted part of his doctoral research at RIKILT Wageningen University & Research. The institute had already developed a chemical analytical test for the toxins that cause diarrhoea (as an alternative to the mouse test), which is now the standard for EU countries. In a comparable test, Nicolas’s method was shown to yield the same results as the chemical test. What makes the neuron test unique is that it can also identify unknown toxins. It is expected that a combination of in vitro and chemical analytical testing will ultimately contribute to a global replacement on mice testing for shellfish monitoring.