Proceedings

EPJ E Highlight - Modelling speed-ups in nutrient-seeking bacteria

Running and tumbling towards nutrient sources

By considering how some bacteria will swim faster within higher nutrient concentrations, researchers have created a more accurate model of how these microbes search for nutrients

Many bacteria swim towards nutrients by rotating the helix-shaped flagella attached to their bodies. As they move, the cells can either ‘run’ in a straight line, or ‘tumble’ by varying the rotational directions of their flagella, causing their paths to randomly change course. Through a process named ‘chemotaxis,’ bacteria can decrease their rate of tumbling at higher concentrations of nutrients, while maintaining their swimming speeds. In more hospitable environments like the gut, this helps them to seek out nutrients more easily. However, in more nutrient-sparse environments, some species of bacteria will also perform ‘chemokinesis’: increasing their swim speeds as nutrient concentrations increase, without changing their tumbling rates. Through new research published in EPJ E, Theresa Jakuszeit and a team at the University of Cambridge led by Ottavio Croze produced a model which accurately accounts for the combined influences of these two motions.

The team’s findings deliver new insights into how self-swimming microbes survive, particularly in harsher environments like soils and oceans. Previously, studies have shown how chemokinesis allows bacteria to band around nutrient sources, respond quickly to short bursts of nutrients, and even form mutually beneficial relationships with algae. So far, however, none of them have directly measured how bacterial swim speeds can vary with nutrient concentration.

Starting from mathematical equations describing run-and-tumble dynamics, Croze’s team extended a widely used model for chemotaxis to incorporate chemokinesis. They then applied the new model to predict the dynamics of bacterial populations within the chemical gradients generated by nutrient distributions used in previous experiments. Through their approach, the researchers showed numerically how a combination of both motions can enhance the responses of populations compared with chemotaxis alone. They also presented more accurate predictions of how bacteria respond to nutrient distributions – including sources which emit nutrients sporadically. This allowed them to better assess the biological benefits of motility.

This was our first experience of publishing with EPJ Web of Conferences. We contacted the publisher in the middle of September, just one month prior to the Conference, but everything went through smoothly. We have had published MNPS Proceedings with different publishers in the past, and would like to tell that the EPJ Web of Conferences team was probably the best, very quick, helpful and interactive. Typically, we were getting responses from EPJ Web of Conferences team within less than an hour and have had help at every production stage.
We are very thankful to Solange Guenot, Web of Conferences Publishing Editor, and Isabelle Houlbert, Web of Conferences Production Editor, for their support. These ladies are top-level professionals, who made a great contribution to the success of this issue. We are fully satisfied with the publication of the Conference Proceedings and are looking forward to further cooperation. The publication was very fast, easy and of high quality. My colleagues and I strongly recommend EPJ Web of Conferences to anyone, who is interested in quick high-quality publication of conference proceedings.

On behalf of the Organizing and Program Committees and Editorial Team of MNPS-2019, Dr. Alexey B. Nadykto, Moscow State Technological University “STANKIN”, Moscow, Russia. EPJ Web of Conferences vol. 224 (2019)

ISSN: 2100-014X (Electronic Edition)

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