Bacterial Filamentation Drives Colony Chirality.

Andrés Aranda-Díaz,Oskar Hallatschek,Kerwyn Casey Huang,Alexandra Grote,Cecilia Rodrigues,Wolfram Möbius,Anton Souslov,Jiawei Sun,Carl Schreck,Nina R Salama

doi:10.1128/mbio.01542-21

Andrés Aranda-Díaz, Oskar Hallatschek + Show 8 more

Open Access

https://doi.org/10.1128/mbio.01542-21

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Abstract

ABSTRACTChirality is ubiquitous in nature, with consequences at the cellular and tissue scales. As Escherichia coli colonies expand radially, an orthogonal component of growth creates a pinwheel-like pattern that can be revealed by fluorescent markers. To elucidate the mechanistic basis of this colony chirality, we investigated its link to left-handed, single-cell twisting during E. coli elongation. While chemical and genetic manipulation of cell width altered single-cell twisting handedness, colonies ceased to be chiral rather than switching handedness, and anaerobic growth altered colony chirality without affecting single-cell twisting. Chiral angle increased with increasing temperature even when growth rate decreased. Unifying these findings, we discovered that colony chirality was associated with the propensity for cell filamentation. Inhibition of cell division accentuated chirality under aerobic growth and generated chirality under anaerobic growth. Thus, regulation of cell division is intrinsically coupled to colony chirality, providing a mechanism for tuning macroscale spatial patterning.

Highlights

Chirality is ubiquitous in nature, with consequences at the cellular and tissue scales
Twisting of E. coli cells is tunable: as cells widen under increasing sublethal levels of A22 treatment [15], the angle of MreB motion, which is thought to signify the placement of new strands of cell wall material [16], rotates and adopts an angle on the opposite side of the line perpendicular to the long axis of the cell, corresponding to a gradual conversion of twisting from left- to right-handed [15]
Using single-cell and colony imaging, we found that A22 treatment and anaerobic growth inhibited growth and reduced colony chirality to near zero, making it unclear whether single-cell twisting was responsible for the change in chiral angle

Summary

Introduction

Chirality is ubiquitous in nature, with consequences at the cellular and tissue scales. To elucidate the mechanistic basis of this colony chirality, we investigated its link to left-handed, single-cell twisting during E. coli elongation. Chirality drives the development of left-right asymmetry generation in organs of Drosophila melanogaster [4] and in the Caenorhabditis elegans embryo [5] Plants twist as they grow, and mutations in SPIRAL2 change that twist from left- to right-handed; this handedness reversal is coupled to a switch from anisotropic growth to isotropic growth [6]. It is largely unknown how chirality at the tissue and organismal scales is linked to cellular and molecular properties. Twisting of E. coli cells is tunable: as cells widen under increasing sublethal levels of A22 treatment [15], the angle of MreB motion, which is thought to signify the placement of new strands of cell wall material [16], rotates and adopts an angle on the opposite side of the line perpendicular to the long axis of the cell, corresponding to a gradual conversion of twisting from left- to right-handed [15]

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Conclusion