Bacterial culture. Bacterial colonies growing on MacConkey's agar in a petri dish. These bacteria are used in research using an artificial gut to model the human intestines. The model allows the health effects of bacteria living in the real gut to be assessed. Certain intestinal bacteria are thought to cause or protect against diseases like irritable bowel syndrome, ulcerative colitis and bowel cancer. The system can also be used to test the effects of prebiotics, nutrients that are eaten to encourage the growth of beneficial intestinal bacteria. The artificial gut was built at Reading University, England, by a team led by Professor Glenn Gibson.