Short-term memory effects in the phototactic behavior of microalgae

Fuente: arXiv
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Autores principales: Laroussi, Taha, Jarrahi, Mojtaba, Amselem, Gabriel
Formato: Preprint
Publicado: 2023
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author Laroussi, Taha
Jarrahi, Mojtaba
Amselem, Gabriel
author_facet Laroussi, Taha
Jarrahi, Mojtaba
Amselem, Gabriel
contents Phototaxis, the directed motion in response to a light stimulus, is crucial for motile microorganisms that rely on photosynthesis, such as the unicellular microalga Chlamydomonas reinhardtii. It is well known that microalgae adapt to ambient light stimuli. On time scales of several dozen minutes, when stimulated long enough, the response of the microalga evolves as if the light intensity were decreasing (Mayer, Nature 1968). Here, we show experimentally that microalgae also have a short-term memory, on the time scale of a couple of minutes, which is the opposite of adaptation. At these short time scales, when stimulated consecutively, the response of C. reinhardtii evolves as if the light intensity were increasing. Our experimental results are rationalized by the introduction of a simplified model of phototaxis. Memory comes from the interplay between an internal biochemical time scale and the time scale of the stimulus; as such, these memory effects are likely to be widespread in phototactic microorganisms.
format Preprint
id arxiv_https___arxiv_org_abs_2312_11303
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Short-term memory effects in the phototactic behavior of microalgae
Laroussi, Taha
Jarrahi, Mojtaba
Amselem, Gabriel
Biological Physics
Soft Condensed Matter
Phototaxis, the directed motion in response to a light stimulus, is crucial for motile microorganisms that rely on photosynthesis, such as the unicellular microalga Chlamydomonas reinhardtii. It is well known that microalgae adapt to ambient light stimuli. On time scales of several dozen minutes, when stimulated long enough, the response of the microalga evolves as if the light intensity were decreasing (Mayer, Nature 1968). Here, we show experimentally that microalgae also have a short-term memory, on the time scale of a couple of minutes, which is the opposite of adaptation. At these short time scales, when stimulated consecutively, the response of C. reinhardtii evolves as if the light intensity were increasing. Our experimental results are rationalized by the introduction of a simplified model of phototaxis. Memory comes from the interplay between an internal biochemical time scale and the time scale of the stimulus; as such, these memory effects are likely to be widespread in phototactic microorganisms.
title Short-term memory effects in the phototactic behavior of microalgae
topic Biological Physics
Soft Condensed Matter
url https://arxiv.org/abs/2312.11303