The Microbial Super-Resolution Microscopy Lab
Current Projects
For Publications see here or Google scholar
From left to right: UPEC invades target cells. Intracellular bacterial communities (IBCs) are formed and multiply into great numbers. When the cells cannot cope with the IBCs, they rupture and filamentous UPEC are readily observed. The molecular details of the late stages of this process and how filaments revert back to rods are poorly understood. Specifically, we want to know the state of the cell division machinery during various stages of filamentation and reversal.
UPEC (Green) cells in the process of infecting bladder cells (Magenta).
Understanding bacterial morphology changes during Urinary Tract Infections
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Urinary tract infections (UTIs) are a global health issue that affects millions of people each year.
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We aim to identify molecular mechanisms that govern division and filamentation of UPEC* cells during infection of human bladder cells. We are looking at the assembly dynamics and composition of the cell division machinery during various stages of filamentation. Specifically, we are looking at a special class of proteins called SPOR-domain proteins, E. coli has four: FtsN, DamX, DedD, and RlpA. One of these, DamX, has been shown to be essential for filamentation. The hope is to better understand the roles of all SPOR-domain proteins during UTI, as they may hold the key for novel therapeutics.
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We are also looking at interspecies bacterial behaviours in multispecies infection models using a combination of five clinically relevant UTI pathogens: UPEC, Enterococcus Faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Proteus mirabilis.
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* Uropathogenic Escherichia coli,
the most common causative agent of UTI.
A UPEC filament that initially grows before reverting back to rods after infection.
Cells are labelled with sfGFP.
2 color STED on DNA and FtsN
Schematic view of standing cells
2 color STED showing the organization of FtsZ and FtsN in a standing cell
PALM imaging of division protein DamX in cells in a standing position
High-resolution imaging of the bacterial cell division machinery
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The goal of this project is literally to get a better picture of the cell division machinery in bacteria. Cell division in E. coli is guided by the protein FtsZ, that together with ~ 30 additional proteins work together to divide the cells.
We are currently developing protocols to use uropathogenic E. coli (UPEC) as a model system. Combining the best of multicolour super-resolution fluorescence microscopy, microfluidics and nano-engineering are we obtaining new high-resolution information about the internal organisation of the components of the division machinery.
The overall rationale behind this is:
"If we know how bacteria divide, can we perhaps figure out how to stop them from doing so, and in that way stop infection?"
E. coli cells growing and dividing in a "mother machine".
Green: Division machinery (FtsZ-mVenus).
Red: DNA (HupA-RFP)
Cell shape and morphology
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As a side project do we also look at how the cell division machinery is behaving in artificially remodelled cells. These cell are formed into Hearts, Stars, Triangles ect. and imaged by super-resolution microscopy.
The aim is to figure out to what extent cell shape influences the division process.
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Live E. coli cells were shaped into various geometrical forms. The cell division protein FtsZ was labeled with mCitrine or mNeonGreen and image by STED nanoscopy. Pseudo-coloured image.
Current funding comes from:
