De Wereld van Wageningen

“I never knew mouse turds smelled this bad!” Gerdien van Doorn, a master student in Nutrition and Health at Wageningen University, did research on mouse turds in the Laboratory for Microbiology, as part of a project for the Top Institute Food and Nutrition. “We did research on the bacteria in the excrements of mice, some of which were fed a certain nutritive substance through their feed. We wanted to determine the influence of a nutritive substance on the kinds and amounts of intestine bacteria. In this way we hope to make clear the health effect of the specific substance. “

You probably do not want to think about eating something that is still alive; you already shiver when you see images of people eating living scorpions, right? But still, unnoticed, you gulp down quite some small creatures: bacteria. In your guts there are even billions of them. And, they are even very useful there, for example for producing vitamins! But, they can also have a less favorable effect, or represent an unfavorable situation in the intestines.   
To determine this for a specific substance, Gerdien and her supervisor Muriel Derrien, determined which kinds, and which amounts of bacteria could be found in the guts of mice, some of which were, and others were not fed the substance during a certain amount of time.
To this end they used MIT (Mouse Intestinal Tract)-chips. Gerdien:”A MIT-chip is a piece of glass to which a lot of small pieces are kind of attached. Pieces of RNA that we made out of mouse turd-DNA can ‘stick’ to these pieces if there is a ‘match’. A machine reads the chips and detects which pieces on the piece of glass are ‘occupied’ with the RNA pieces from the excrements. The data is the translated by a software program to show the bacteria we want to distinguish. It is quite a bit of ingenious technique that lets us recognize the bacteria.”
Gerdien is enthusiastic about the special laboratory technique: “The good thing about using a chip is that the research goes to the basis. Also, with one analysis you can measure the presence of all the bacteria that have been identified so far.”
 
Yet there is quite a big downside to the research when it comes to interpreting the data. Gerdien: “As is the case more often, we also have the ‘chicken-egg’ problem: Does the composition of bacteria in the intestines change as a consequence of the substance that was taken in, or can the change be ascribed to changes on body-level, for example in the gut-cells? Another question remains whether the survival of the bacteria is different because the specific substance has a restraining or stimulating influence on bacteria growth.

Despite this bad aftertaste there is a lot that can be learned from the data and that intrigues Gerdien: “Not the smell of mouse turds, but the technique of the chip makes me hungry for more!”