How bacteria drill into our cells and kill them

Posted by ap507 at Dec 03, 2014 11:00 AM |
Researchers involved in study of bacterial ‘nanodrills’
How bacteria drill into our cells and kill them

This image shows how the individual toxins (in purple) assemble into arcs and rings on the surface of the cell, then (in turquoise) slice through the cell membrane. Credit: eLife

A team of scientists has revealed how certain harmful bacteria drill into our cells to kill them. Their study shows how bacterial ‘nanodrills’ assemble themselves on the outer surfaces of our cells, and includes the first movie of how they then punch holes in the cells’ outer membranes.

The research, published in the journal eLife, supports the development of new drugs that target this mechanism, which is implicated in serious diseases.

The team brings together researchers from the University of Leicester, UCL, Birkbeck, University of London and Monash University (Melbourne) and  was done in the labs of Professor Peter Andrew (Head of Department) and Dr Rana Lonnen (CSO of Axendos Therapeutics and Honorary Senior Lecturer) at the University of Leicester's Department of Infection, Immunity and Inflammation.

Unlike drills from a DIY kit, which twist and grind their way through a surface, bacterial nanodrills do not contain rotating parts. Rather, they are ring-like structures (similar to an eyelet) built out of self-assembling toxin molecules. Once assembled, the toxins deploy a blade around the ring’s inside edge that slices down into the cell membrane, forming a hole.

A big surprise for the team was that complete rings aren’t needed to pierce the cell membrane: even relatively short fragments are still able to cut holes, albeit smaller ones, and hold them open, allowing bacteria to feed on the cell’s contents. Together, these findings give a detailed view of how these bacterial toxins drill holes in cell membranes.