Reassessment of the distinctive geometry of Staphylococcus aureus cell division

Bruno M Saraiva,Léo C Caulat,Ana R Pereira,Mário J Ferreira,Nathalie T Reichmann,Mariana G Pinho,Moritz Sorg

doi:10.1038/s41467-020-17940-9

Abstract

Staphylococcus aureus is generally thought to divide in three alternating orthogonal planes over three consecutive division cycles. Although this mode of division was proposed over four decades ago, the molecular mechanism that ensures this geometry of division has remained elusive. Here we show, for three different strains, that S. aureus cells do not regularly divide in three alternating perpendicular planes as previously thought. Imaging of the divisome shows that a plane of division is always perpendicular to the previous one, avoiding bisection of the nucleoid, which segregates along an axis parallel to the closing septum. However, one out of the multiple planes perpendicular to the septum which divide the cell in two identical halves can be used in daughter cells, irrespective of its orientation in relation to the penultimate division plane. Therefore, division in three orthogonal planes is not the rule in S. aureus.

Highlights

Staphylococcus aureus is generally thought to divide in three alternating orthogonal planes over three consecutive division cycles
To follow the planes of division of cells of the methicillinresistant S. aureus (MRSA) strain COL, we labelled the membrane with Nile Red and the cell wall with a fluorescent derivative of wheat germ agglutinin (WGA-488), a lectin that binds Nacetylglucosamine residues present in the peptidoglycan and in teichoic acids of the S. aureus cell wall
This is important because splitting of the septum of S. aureus cells occurs via an extremely fast (

Summary

Introduction

Staphylococcus aureus is generally thought to divide in three alternating orthogonal planes over three consecutive division cycles. We have recently shown that S. aureus cells are not perfectly spherical, as they undergo slight elongation mediated by the action of the penicillin binding protein PBP3, a peptidoglycan transpeptidase, and the SEDS (Shape, Elongation, Division and Sporulation) protein RodA proposed to be a peptidoglycan synthase with glycosyltransferase activity[3–6] While both rod-shaped bacteria and ovococci divide in successive parallel planes, perpendicular to the long axis of the cell, a distinctive characteristic of S. aureus division is that it is thought to occur in three alternating orthogonal planes over three consecutive division cycles. Progression of chromosome segregation releases midcell from Noc inhibition, allowing the FtsZ ring to be assembled at that position and defining the plane of division[14,15] Both models assume that scars of the two previous divisions divide the cell in quadrants. We questioned if S. aureus does divide according to this geometry

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Conclusion