Microbiology Mastermind

An outdated view of the division of labor between our body and our brain is that all neural activity and consciousness reside in our brain, while action is the purview of the body (which is directed by the brain). This view has been modified in recent decades by the recognition that neural activity not only occurs in the spine and the brain (the central nervous system), but also throughout our gut. In fact some biologists today claim not only does our consciousness reside in central nervous system, but also in our gut biome. 

This view stems from the recent understanding of the crucial role that microorganisms play in our lives. An astounding fact is that the trillions of cells that constitute our body—all those that share our personal DNA—are outnumbered by various kinds of bacteria with their own DNA. For every one of our cells, there are 10 bacteria residing within, which are not “us.” We are inhabited by a legion of symbiotic organisms that are not really us... and yet they are. We could not survive without their work. It is likely the same for most plants and animals. We all are what is called “holobiants.” Our digestive system, for example, is literally controlled by gut bacteria—not us. Other examples are bacteria that help cows to digest grass, and similar species of bacteria that allow termites to digest the cellulose of trees.

Not only do these many kinds of bacteria perform a crucial function in the workings of our body, but since they evolve so rapidly, they help us adapt to rapid environmental changes. While our body's organs may take years or centuries to evolve, our resident microorganisms can evolve in days.

But the workings of our symbiotic selves—that is, the cooperative interaction between our cells and those jillions of microorganisms—is not confined just to bodily functions. Some biologists are realizing that our mental functions—yes, even our consciousness—is influenced by bacteria. Since the gut plays a role in our nervous system, gut bacteria can influence brain activity—literally affecting our emotions and cognitive processes. It has been demonstrated, for example, that gut bacteria affect the amygdala and thus the level of stress that we experience. Microorganisms alter our serotonin and oxytocin levels and their effect on emotions. In fact, 95% of our serotonin is created and stored in the gut!

Thus, each of us is legion. We are not a single being. We are a collective... a symbiont or holobiont. We must learn to take care of this legion, and find ways to deal with invasive, disease-causing bacteria, without damaging all our friendly, interior bacteria by taking doses of antibacterial medications. How do we get beyond our selfish perspective and take better care of the collective?