Cells live in a small world

If you are microbe, or a person, it’s often not good to be surrounded by individuals just like you.

Go to the profile of Alma Dal Co
Feb 11, 2020

If you are microbe, or a person, it’s often not good to be surrounded by individuals just like you. This is the provocative lesson from our work on bacterial consortia. This work itself is born interactions between five scientists with very different backgrounds.

Why did I study interactions in bacterial communities? Because communities properties arise from interactions. Bacterial communities can be thought as systems composed of parts, the cells, connected via a dense network of biochemical interactions. These cells live in contact with each other and move little. Each cell is chemically connected to its neighbors, which affect the cell’s phenotype, growth, and survival. The combined network of interactions determines the properties of a community, such as its growth and collective metabolic processes. 

What is the size of the neighborhood that affects a cell’s phenotype? This quantity seemed to be the key to reconstruct the network of interactions between members in a community. We decided to build a new experimental system for growing microbial communities and measuring interactions between individual cells. For that we needed a variety of expertise to design a model bacterial community, build a new microfluidic device, perform time-lapse experiments, develop image analysis software, construct a method to measure interactions, and a mathematical model to interpret the results. Our team became quickly interdisciplinary!

This work occupies a special place in my mind because it has been my personal bridge between physics and wet-lab biology. It shaped me into a Chimera, half physicist and half experimental biologist, which is the Chimera I like to be. This project was challenging, and it was made possible by interactions between all authors. Working together showed us that it is good to be surrounded by individuals different from you. Both for people, and for microbes.

Alma Dal Co

Mutualistic relationship: two mutualistic Escherichia coli strains, shown in yellow and purple, grow inside a microfluidic chamber and exchange beneficial compounds. Images of the community are recorded in time and growth rates of single cells are measured. Brighter colors in this image indicate faster growth rates. Cells closer to the mutualistic partner grow faster as they receive more of the beneficial compound from the partner.

Dive into movies of our communities and a three-dimensional rendering of the microfluidic device used for all experiments:

Watch our communities: pic.twitter.com/DroXqhjoEN

Watch a 3D rendering of the microfluidic device: pic.twitter.com/m0S8G5OOGj

Go to the profile of Alma Dal Co

Alma Dal Co

Postdoc, Harvard

I was there doing physics when biology run over me • Now into Ecology, Microbes, Collective behavior.


Go to the profile of Zhong-Jian Liu
Zhong-Jian Liu 7 days ago

Hi Alma - is there a link to the movie? It sounds great 

Go to the profile of Alma Dal Co
Alma Dal Co 7 days ago

I added the link!