"Bacteria are common on exposed surfaces, including the food products we consume," Trempy said. "Simply knowing they are there doesn't completely tell you, in a direct measurement, about their potential to make you sick or whether the food is safe to eat."
Existing tests only work to detect bacteria that have already been characterized, based on a specific sequence of DNA or type of protein they produce. Such tests can't tell whether the contaminating bacteria are alive or dead, they can't directly assess their toxic potential and sometimes don't detect newly emerging or genetically rearranged strains as bacteria mutate.
The new approach, by contrast, is built on the unusual characteristics of certain "chromatophore" or pigment bearing cells, called erythrophores, from Siamese fighting fish, whose response to specific toxic chemicals have been studied in detail by Trempy's collaborator, OSU biochemist Phil McFadden.
This research found that when Siamese fighting fish encounter certain stressful or threatening environmental conditions, such as exposure to toxic chemicals like mercury, the erythrophores change appearance, and the pigment moves in a characteristic pattern to an internal part of the cell. The change in pigment location in response to a toxic chemical is rapid, obvious and can be numerically described.
Another kind of stressful or threatening situation which also causes the location of pigment to change is the toxic threat posed by illness-causing bacteria. Some of these bacteria are associated with food.
"We discovered that the pigment bearing cells, erythrophores, respond immediately to certain food associated, toxin producing bacteria responsible for making humans sick," Trempy said. "There is potential to directly assess the toxic behavior of the contaminating bacteria, not just the simp
|Contact: Janine Trempy|
Oregon State University