Unique bacteria that survive by employing multicellular behavior

Summary

An electron microscopy images of multicellular magnetotactic bacteria that featured on the covers of the 2022 edition of The ISME Journal. The image was produced by Schaible and co-workers under the group's NASA awards. Credit: Roland Hatzenpichler / Montana State University In a recent study, researchers gained new insight into the lives of bacteria that survive by grouping together as if they were a multicellular organism. The organisms in the study are the only bacteria known to do this in this way, and studying them could help astrobiologists explain important steps in the evolution of life on Earth. The work is published in the journal PLOS Biology. The organisms in the study are known as multicellular magnetotactic bacteria (MMB). Being magnetotactic means that MMB are part of a select group of bacteria that orient their movement based on Earth's magnetic field using tiny "compass needles" in their cells. As if that weren't special enough, MMB also live bunched up in collections of cells that are considered by some scientists to exhibit "obligate" multicellularity, the trait on which the new study is focused. In biology, obligate means that an organism requires something for survival. In this case, it means that single cells of MMB cannot survive on their own. Instead, cells live as a consortium of multiple cells that behave in many ways like a single multicellular organism. This requirement to live together means that when MMB reproduce, they do so by replicating all the cells in the consortium at once, doubling the total number of cells. This large group of cells then splits into two identical consortia. Electron microscopy image and cartoon of a MMB consortium, highlighting its characteristics features that includes a hollow space at the center of the cell consortium. Credit: PLOS Biology (2024). DOI: 10.1371/journal.pbio.3002638 MMB are the only example of bacteria that are known to live like this. Many other bacteria clump together as simple aggregates of...