Bacteria’s Sense of Smell

The single-celled organisms obviously lack anything like a nose, but nonetheless, scientists at Newcastle University have shown that at least one type of bacteria can respond to the presence of ammonia in nearby air—a behavior essentially like smelling.

Newcastle microbiologists Grant Burgess and Reindert Nijland (now at University Medical Center Utrecht) studied the bacterium B. licheniformis. One culture of the bacteria was “fed” a growth medium that would cause the bacteria to produce ammonia. Another culture, placed in a separate container, was in a medium that allowed the bacteria to produce slimy biofilms, which typically occurs if the bacteria come in contact with ammonia. (To the bacteria, ammonia indicates a food source close by, and the biofilm helps the bacteria move toward it.)

The scientists then watched as the second group of bacteria began producing biofilms, despite not being in contact with the ammonia produced by the first group. This indicated that the bacteria were able to sense the nearby ammonia, despite not being in direct contact with it. Moreover, the bacteria of the second group physically closest to the first group produced the most biofilm.

Nijland speculated, “If very simple organisms such as bacteria are capable of this[,] that would imply that this ability evolved much earlier than expected.” Of course, the alternative explanation is that God gave bacteria yet another complex capability, designing it perfectly for the original purpose He intended.