Ecotoxicity testing

• Using MARA and LumiMARA as an alternative to ecotoxicity testing with a single species of bacteria is a simple way of increasing the breadth and genetic diversity of ecotoxicity testing, whilst retaining other benefits of using a microbial test.
• Each strain within the MARA and LumiMARA test can respond differently to toxins present in a sample, and this creates a unique profile or "fingerprint" for each sample, which can be used to assess changes in toxicity over time or between locations.

Bacteria are good candidates for ecotoxicity testing because of a number of factors, including their small size, their rapid growth rate and their ease of handling. The use of bacterial bioassays to assess toxicity is well established, and single species bacterial tests are commonly used across a broad range of industry and environmental applications as they are convenient to use, and give rapid results.

The best known tests make use of the naturally luminescent bacteria Aliivibrio fischeri (previously known as Vibrio fischeri). These tests are based on the fact that exposure to toxins disrupts the bacteria's respiratory processes, which in turn results in a reduction in light output. Reduction in light output is an easily measurable response that can be used to assess the toxicity of samples.

NCIMB's MARA and LumiMARA bioassays make use of the genetic diversity of microbes and the ease with which they can be handled, to take the concept of the microbial bioassay a step beyond single species testing.

Single species bacterial testing is generally based around assessment of the acute toxicity response of a single marine species.  In contrast, testing using both MARA and LumiMARA gives a measure of acute and chronic toxicity, encompasing marine, freshwater and terrestrial species of bacteria in addition to a yeast.