Candida auris fungi, emerging multidrug resistant fungus (Image: Kateryna Kon)

What does it mean to grow old? Many fields have offered answers, but none of them provides a universal theory. According to former SFI Postdoc Jacopo Grilli (International Centre for Theoretical Physics), we understand the when but not the how of aging: when the components of an organism fail, but not the causes of these failures or if the process serves an evolutionary purpose.

This February, a diverse international working group will meet at SFI to find a fresh take on the problem. Grilli and fellow organizers SFI Professor Chris Kempes, External Professor Srividya Iyer-Biswas (Purdue), and Matteo Osella (University of Turin) will focus the discussion on single-celled organisms like bacteria and yeast in hopes of finding generalities in simpler settings. Part of the challenge, Grilli says, has been that aging happens across many scales, from DNA and proteins to organs and entire organisms. By narrowing the inquiry, the group intends to prune the complications and see aging in its essence. A single yeast cell may provide analogies for human beings, and colonies are in some ways like organs. “Looking at things in this way,” says Grilli, “allows us to see multiple levels at the same time.”

One goal is to identify fruitful questions for a laboratory setting. Grilli notes the project has recruited members “with the experimental expertise to actually test theories in the real world.” Sri Iyer-Biswas and Lin Chao (UC San Diego) are two such researchers whose innovative labs can track individual bacteria throughout their life cycles.

“A key challenge in aging studies has been to identify clean experimental systems in which extrinsic (e.g., environmental) and intrinsic (e.g., genetic) factors contributing towards the aging of an organism can be precisely controlled,” says Iyer-Biswas. “Consequently, even basic questions such as how ‘aging’ should be defined remain open.”

In her SFI Community Lecture, Iyer-Biswas noted that new methods in cell biology reveal a cellular unit of time. “One can now ask questions we’ve had a hard time getting a handle on previously,” she observed. “The scaling laws for growth and division of cells as they age remain the same, except the cellular unit of time itself gradually slows down.”

The implications are far-reaching. This workshop, Grilli hopes, “can unify views on aging, how it’s similar and different across the tree of life.” As biology itself approaches its 400th year, perhaps the discipline is ripe for more perspective.

Read more about the "Aging in Single Celled Organisms: From Bacteria to the Whole Tree of Life" Working Group, running February 10-12. 

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