The resilience of natural systems: a fascinating mystery

The complexity of natural mechanisms represents one of the most intriguing and challenging issues to tackle. A fascinating mystery lies in how natural systems manage to be so resilient. How do they maintain stable behaviors and fundamental properties essential for survival despite vast environmental variations and the uncertainty of the contexts in which they operate?

Giulia Giordano’s research: a window into complexity
Giulia Giordano’s research aims to answer these questions by studying complex phenomena across various fields, from biology to ecology, from medicine to epidemiology. Her work is also part of the INSPIRE project (Integrated Structural and Probabilistic Approaches for Biological and Epidemiological Systems), funded by the European Research Council (ERC).

The extraordinary resilience (also referred to as robustness) of biological phenomena manifests at all levels—from protein interactions to the complex genetic regulatory networks within cells, and even to the coordinated behavior of tissues, organs, organisms, and species. A striking example is the bacterium Escherichia coli, which moves by alternating between straight runs and self-rotation phases, exploring its surroundings through a random path (as shown in Figure 1). Surprisingly, the frequency of these phases remains constant despite environmental variations. Even when the environment is perturbed, such as by the continuous injection of glucose, the frequency experiences only a temporary alteration before returning to its original value. How does the bacterium maintain this systematic behavior?

The answer requires the construction of a mathematical model of bacterial behavior: by associating a system of equations with a visualization of their structure, we can observe how the system’s variables interact. It becomes evident that everything depends on the interconnections between the components regulating the bacterium’s movement rather than on the specific characteristics of individual components.

To uncover the key to a system’s resilience, the INSPIRE project (Figure 2) examines its structure—how its fundamental components are connected and interact with one another. In many cases, structure alone allows us to understand why a system exhibits a specific qualitative behavior, regardless of other factors, even in the face of uncertainties and perturbations, as seen with E. coli. Modifying the structure is also crucial for precisely controlling a system to induce a desired behavior. For example, E. coli has been engineered by altering its DNA structure to make it produce insulin.

Giordano also aims to intervene more precisely in the structure of natural phenomena using new drugs and biotechnologies. She believes this approach could significantly enhance our lives and well-being, enabling the creation of robust and resilient artificial systems.

Giulia Giordano’s research provides a fresh perspective on the robustness of natural systems, highlighting the importance of structure in complex system dynamics. This approach could revolutionize how we understand and interact with biological systems, paving the way for new solutions in medicine, ecology, and biotechnology. Nature continues to teach us valuable lessons, and through the work of scientists like Giordano, we can hope to apply this knowledge to improve our lives and face future challenges with greater resilience and precision.