Exploring bacterial multicellularity: study of long-distance metal transport and intercellular junctions in Actinosynnema mirum

In recent decades, research has revolutionized the conventional view of bacteria as solitary entities suspended in liquid media.

Bacterial multicellularity, which leads to the formation of complex structures such as biofilms that comprises diverse bacterial species, challenges the outdated paradigm.

Even less is known about the multicellular bacteria capable of aerial growth, raising questions about their access to essential resources found only in the substrate inaccessible to them.This project focuses on the study of two closely related bacteria, Actinosynnema mirum and Actinosynnema pretiosum, which form tree-like structures known as synnemata.

Data have revealed the presence of intercellular cell junctions, the functions of which remain elusive but undoubtedly important within synnemata.

Additionally, metal distribution within the synnemata has been studied using nano X-Ray Fluorescence, indicating the presence of metals throughout the aerial mycelium and patterns of discrete, non-uniform intracellular metal concentrations.This project aims to challenge the existing model of long-distance metal transport in synnemata.

It begins with the development of translational fusion reporters, labeling membrane transporters with mNeonGreen, coupled with confocal microscopy to assess the relevance of the proposed model, depicting a restrained spatial localization of the transporters at cell junctions. Advanced cryoEM techniques will also be used to better characterize the cell junctions within synnemata.

By examining metal transport and distribution within these multicellular structures, this research aims to shed light on their intricacies and potentially revolutionize our understanding of how bacteria efficiently share essential resources over long distances.In summary, this project ventures into the fascinating world of bacterial multicellularity and resource-sharing mechanisms within synnemata, providing new insights into a novel aspect of bacterial life.