From flagellar motor behavior to bacterial swimming: defining a reference state for motility dynamics in Magnetospirillum gryphiswaldense
- 1INSTITUT DE BIOSCIENCES & BIOTECHNOLOGIES D'AIX-MARSEILLE
Abstract
Cell motility is powered by the bacterial flagellar motor, a rotary nanomachine whose activity is dynamically modulated by external stimuli. In Magnetospirillum gryphiswaldense, magnetic and chemical inputs are thought to converge at the level of motility control, yet the mechanisms underlying chemotactic regulation remain poorly understood. Here, we seek to establish a quantitative reference-state of a model strain of magnetotactic bacteria through bacterial flagellar motor dynamics. To achieve this goal, magnetotaxis was kept as a natural factor by keeping the earth's magnetic field as the only source of magnetism. To avoid aerotaxis bias, oxygen gradients were removed by implementing two different constant oxygen conditions: environmental oxygen exposure, and limited oxygen exposure. Together, the tethered-cell bacterial flagellar rotational assay and the free-swimming assay in the absence of external stimuli presented in this paper establish a framework for investigating motor and cellular swimming adaptation to magnetic, aerotactic, and chemical signals. Under reference-state conditions, the bacterial flagellar motor showed a tendency to exhibit log-normal distributions for the time spent in each motor state: runs in different directions (counter-clockwise and clockwise), and pause. A semi-Markov reference-state model was developed to provide a quantitative description of bacterial flagellar motor dynamics. The model revealed that cell magnetic polarity modulates the transition pathways leading to the paused state, whereas oxygen, in the absence of a gradient, primarily regulates residence in each motility state.
Related
- Thermal fractuations assist high-speed rotation of the bacterial flagellar motor at low load
- Flagellar number governs bacterial spreading and transport efficiency.
- Structural insights into the assembly mechanism of the molecular bushing in the bacterial flagellar motor
- Potassium modulates Phytophthora zoospore motility and flagellar beating through dose-dependent effects
- Core–sheath coupling controls flagellar curvature and motility in Leptospira
BibTeX
@misc{martinez2026from,
title = {{From flagellar motor behavior to bacterial swimming: defining a reference state for motility dynamics in Magnetospirillum gryphiswaldense}},
author = {D. R. Roesch Martinez and G. Delabre and E. Gachon},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.09.750318},
url = {https://www.biorxiv.org/content/10.64898/2026.09.09.750318v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - From flagellar motor behavior to bacterial swimming: defining a reference state for motility dynamics in Magnetospirillum gryphiswaldense
AU - D. R. Roesch Martinez
AU - G. Delabre
AU - E. Gachon
PY - 2026
DA - 2026/09/09
PB - bioRxiv
DO - 10.64898/2026.09.09.750318
UR - https://www.biorxiv.org/content/10.64898/2026.09.09.750318v1
AB - Cell motility is powered by the bacterial flagellar motor, a rotary nanomachine whose activity is dynamically modulated by external stimuli. In Magnetospirillum gryphiswaldense, magnetic and chemical inputs are thought to converge at the level of motility control, yet the mechanisms underlying chemotactic regulation remain poorly understood. Here, we seek to establish a quantitative reference-state of a model strain of magnetotactic bacteria through bacterial flagellar motor dynamics. To achieve this goal, magnetotaxis was kept as a natural factor by keeping the earth's magnetic field as the only source of magnetism. To avoid aerotaxis bias, oxygen gradients were removed by implementing two different constant oxygen conditions: environmental oxygen exposure, and limited oxygen exposure. Together, the tethered-cell bacterial flagellar rotational assay and the free-swimming assay in the absence of external stimuli presented in this paper establish a framework for investigating motor and cellular swimming adaptation to magnetic, aerotactic, and chemical signals. Under reference-state conditions, the bacterial flagellar motor showed a tendency to exhibit log-normal distributions for the time spent in each motor state: runs in different directions (counter-clockwise and clockwise), and pause. A semi-Markov reference-state model was developed to provide a quantitative description of bacterial flagellar motor dynamics. The model revealed that cell magnetic polarity modulates the transition pathways leading to the paused state, whereas oxygen, in the absence of a gradient, primarily regulates residence in each motility state.
ER -