Magnetotactic bacteria (MTB) are a diverse group of microorganisms that are able to biomineralize magnetic nanoparticles. Most MTB remain uncultured, making population-level characterization from natural environments difficult. We report the discovery of a new and diverse MTB-rich site in the Ogre River, Latvia, and present an integrated approach combining 16S rRNA sequencing, transmission electron microscopy, and novel open-source, automated image-based physical methods to characterize bacteria populations within environmental samples. We introduce a pipeline for cell velocimetry using a static magnetic field and a method to classify cell populations based on their magnetic moment using a modified U-turn method where cell behavior is studied in an alternating magnetic field. This study demonstrates that our physical analysis methods provide a powerful, fast, and robust toolset for MTB population analysis in complex environmental samples.
Cite
@article{arxiv.2506.04011,
title = {Image-based physical characterization of magnetotactic bacteria from an environmental sample},
author = {Mara Smite and Mihails Birjukovs and Mila Sirinelli-Kojadinovic and Sandrine Grosse and Agnese Kokina and Janis Liepins and Dita Gudra and Megija Lunge and Davids Fridmanis and Mihaly Posfai and Andrejs Cebers and Damien Faivre and Guntars Kitenbergs},
journal= {arXiv preprint arXiv:2506.04011},
year = {2025}
}