The social network of microbes - how interdependencies shape communities

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The paper in Nature Reviews Microbiology is here:

Microbes Like You and Me
In recent history, social media has become an intricate part of our daily lives. These online tools make it easy for us to stay in touch with friends and family and to maintain our social network, however, they serve as a poor substitute for the face-to-face interactions of going out for drinks or having dinner with friends. The desire to establish and maintain a strong social network is what makes us human. Contemplating this idea on a long train ride up the coast to Santa Barbara, I noticed that strong bonds are not only a prerequisite for humans – microbes also form their own kind of social network, following similar rules as we humans do. 

Train Ride Along the California Coast 

Our group has long worked on unraveling the intertwined interactions occurring in microbial communities and our current work has revealed complex networks of interactions and interdependencies in every environment we studied, from ocean sediments to the human gut and skin. Several other groups have recently also reported interdependencies of various microbes living in lakes or soils. All these intertwined networks suggest intricate relationships that have evolved over a long period of time. Applying the social network analogy to microbes - you realize, they are just like us humans… i) they love to hang out in groups (you rarely find an isolated single species in nature); ii) they spend time with others they have things in common with (e.g., aerobes with aerobes); iii) they give and take something in a relationship (the reliance of external nutrients for growth, i.e. auxotrophy, is rampant in the microbial world); iv) they move in defined social circles, following their preference (in contrast to humans, these preferences and needs are genome-encoded in microorganisms); and v) their group of friends is dynamic (the type of interaction and “friends” might change over the course of time, but general preferences remain constant).

In our Opinion paper, we highlight latest evidence for the existence of such a social network in the microbial world. Furthermore, we discuss the implication an intertwined microbial network has on health and disease. Having insight into the social network of a specific microbe would enable us to understand what makes a microbe tick. Specifically, unraveling the interdependences of pathogens could provide new treatment options for infectious diseases. With this knowledge we could for example introduce a new friend (i.e. probiotic), or buy a group of microbes “an extra round of drinks” (i.e. prebiotic) so they stick around longer. We could use the information about their interaction network to manipulate them and keep them content for a long period of time. So while we are slowly getting a glimpse into their existing social network, we are just starting to understand what social media tools microbes deploy to call a friend or to stay in touch over long periods of time. Stay tuned...

The paper in Nature Reviews Microbiology is here:

Karsten Zengler

Associate Professor, UC San Diego