Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2511.09534 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866915982595850240 |
|---|---|
| author | Gargasson, Adam Bouvard, Julien Douarche, Carine Mergaert, Peter Auradou, Harold |
| author_facet | Gargasson, Adam Bouvard, Julien Douarche, Carine Mergaert, Peter Auradou, Harold |
| contents | Bacteria can adjust their swimming behaviour in response to chemical variations, a phenomenon known as chemotaxis. This process is characterised by a drift velocity that depends non-linearly on the concentration of chemical species and its "local" gradient. To study this process more effectively, we optimised a 3-channel microfluidic device to generate a stable, linear concentration profile of chemoattractants. This setup allows us to monitor the response of $Escherichia$ $coli$ to casamino acids or $α$-methyl-DL-aspartic acid at the individual level. By analysing the movement of a population of individuals both in fluid and on surfaces, we achieve faster, more accurate quantification of the population's chemotactic response. In the fluid, the chemotactic response is described by the equation $v_c=χ(c) \nabla c$, with $χ(c) = χ_0 /[(1 + c/c_-)(1 + c/c_+)]$ the chemotactic susceptibility. For $c_- \ll c \ll c_+$, i.e. when bacteria perform chemotaxis, the bacterial chemotactic velocity is proportional to the concentration gradient divided by the concentration and $v_c \propto \nabla c/c = \nabla (\log c)$. However, on surfaces, the chemotactic flux is inhibited. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_09534 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Local chemotactic response of $Escherichia$ $coli$ in fluid and near surfaces Gargasson, Adam Bouvard, Julien Douarche, Carine Mergaert, Peter Auradou, Harold Fluid Dynamics Bacteria can adjust their swimming behaviour in response to chemical variations, a phenomenon known as chemotaxis. This process is characterised by a drift velocity that depends non-linearly on the concentration of chemical species and its "local" gradient. To study this process more effectively, we optimised a 3-channel microfluidic device to generate a stable, linear concentration profile of chemoattractants. This setup allows us to monitor the response of $Escherichia$ $coli$ to casamino acids or $α$-methyl-DL-aspartic acid at the individual level. By analysing the movement of a population of individuals both in fluid and on surfaces, we achieve faster, more accurate quantification of the population's chemotactic response. In the fluid, the chemotactic response is described by the equation $v_c=χ(c) \nabla c$, with $χ(c) = χ_0 /[(1 + c/c_-)(1 + c/c_+)]$ the chemotactic susceptibility. For $c_- \ll c \ll c_+$, i.e. when bacteria perform chemotaxis, the bacterial chemotactic velocity is proportional to the concentration gradient divided by the concentration and $v_c \propto \nabla c/c = \nabla (\log c)$. However, on surfaces, the chemotactic flux is inhibited. |
| title | Local chemotactic response of $Escherichia$ $coli$ in fluid and near surfaces |
| topic | Fluid Dynamics |
| url | https://arxiv.org/abs/2511.09534 |