Microbial Morphology and Development
Welcome to the Microbial Morphology and Development Research Group, led by A/Prof Iain Duggin, at the Australian Institute for Microbiology and Infection, University of Technology Sydney, Australia.
Microbial cells are impressively dynamic, and quick to respond to environmental changes. We want to know how and why they do this, by determining the functions and regulation of structural changes in the cell envelope, including those required for cell morphology and division, in response to environmental conditions and stresses.
Much of our work centers around the cytoskeletal* proteins that form filaments in cells to effect changes in envelope shape.
Our research uses and develops methods for model microorganisms. We have led the development of Haloferax volcanii (archaea found in salt-lakes) as a powerful model for cell biology that is particularly useful for comparative and evolutionary studies. We also study Escherichia coli, particularly Uropathogenic E. coli (UPEC) that cause urinary tract infections. The applications of our research include biotechnology and vaccine and drug design/delivery.
Our scientific publications may be found here.
Left: Some techniques and cells we work with, including CetZ crystal lattice and cytoskeletal elements in H. volcanii, Coulter cytometry, microbiology and cell division phenotypes of H. volcanii (e.g. baggy-trousers cell). Centre: Crystal structure of CetZ2 protofilament from H. volcanii. Right: Spectacular but devastating eruption of UPEC as extremely long filamentous cells from an infected human bladder cell (compared to rod-shaped UPEC at top).
*What are cytoskeletons and cytoskeletal proteins?
Like the human body, all cells have a skeleton called the cytoskeleton, which provides structure for movement. The "bones" of these cytoskeletons are made of nano-scale filaments or mesh-like structures, composed of cytoskeletal proteins, which assemble into a flexible and dynamic scaffold that controls the internal structure and overall shape of the cell as it grows. Cytoskeletal proteins are essential to life, and are important targets for drugs and other therapies to treat infectious diseases and cancer.
The "workers" on this scaffolding include regulatory proteins of the cytoskeleton; these control how, where and when the cytoskeleton is assembled. Cytoskeletal structures in turn can direct the movement or assembly of cellular components and structures. Microbes generally have a strong cell envelope that maintains the cell shape; many of the internal cytoskeletal proteins in microbes are involved in controlling the location or assembly of the structural components in the cell envelope.
In bacteria, complex systems based on the cytoskeletal proteins FtsZ and MreB (homologs of tubulin and actin in eukaryotes), direct the assembly and shape of the cell envelope during cell growth (MreB) and division (FtsZ). In many archaea, FtsZ controls division, whereas another tubulin-like protein, CetZ, controls cell shape (see publications for further information). A feature common to most regulated cytoskeletal proteins is nucleotide (GTP/ATP) binding and hydrolysis (breakdown). This provides a way to control the assembly or disassembly of the cytoskeleton and can direct the movement and mechanical activities of the cytoskeleton.