For decades, the mechanisms behind the origin of neurodegenerative diseases like ALS have ranged from vague to downright murky. Now, a 1-millimeter worm composed of just 959 cells may offer a clue.

A new University of Florida study used nematodes to better understand the effect of different bacterial species on protein misfolding, a phenomenon associated with disorders like Parkinson’s disease and dementia.

Although previous research has found connections between gut bacteria and degenerative brain disorders, the findings are the first indication that disease-causing bacteria can encourage a hiccup in the folding process.

Despite their minuscule size, the study’s unlikely heroes still have muscles, nerves and intestines. That allowed researchers to simulate the effect of harmful bacteria that can infect the gut of humans.

When added, the “bad” bacteria did more than disrupt protein folding in the worms’ guts — they also wreaked havoc on protein folding throughout muscles, nerve cells and gonads. In contrast, beneficial gut bacteria help create a molecule that prevents any protein clumps, the “speed bumps” responsible for derailing the protein folding process.

To differentiate between good and bad bacteria, researchers used a method that made problematic protein clumps glow green. Then, aside from their ghostly glow, specimens colonized by the “bad” bacteria showed a dip in mobility — a telltale symptom seen in many people with certain neurodegenerative diseases.

Since the tiny nematodes do not have brains, the researchers plan to take their findings to more complex organisms whose biological systems mimic those of humans more closely. But for now, it looks like they opened a promising can of worms.