2011 Postgraduate Research Competition - UNSW Science - The ...

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A picture tells a thousand nerves
Edward Lum and Helen Swarbrick
School of Optometry & Vision Science
Abstract
Orthokeratology (OK) is a clinical technique that uses specially designed rigid contact lenses
to reshape the corneal contour to temporarily correct refractive error. This study aimed to
map the sub-basal nerve plexus (SBNP) in the cornea of an OK lens wearer.
Method: Laser scanning in vivo confocal microscopy was performed on two subjects: a nonlens
wearer and medium-term OK lens wearer (9 years of wear). Scans were performed on
the right eye while the left eye fixated a moving target. A total of 575 and 676 contiguous
images of the SBNP were taken from the non-lens and OK lens wearing subjects respectively.
These images were used to construct maps of the central to mid-peripheral SBNP.
Results: In the non-lens wearing eye, nerves radiated towards a whorl-like complex centred
nasally and inferiorly. In the OK lens wearing eye, this whorl pattern was absent, replaced by
a tortuous network of nerve fibres centrally, and thicker curvilinear fibres mid-peripherally,
particularly in the nasal, inferior and temporal regions.
Conclusion: This is the first study to map the corneal SBNP in an OK lens wearer. It
demonstrates that OK lens wear alters the normal SBNP distribution observed in healthy, nonlens
wearing eyes.
Abstract
Using viruses to break up bacterial infections
Janice Hui, Scott Rice and Staffan Kjelleberg
School of Biotechnology & Biomolecular Sciences
Bacteria can also get sick because of viruses, called bacteriophages/phages. As with viruses
on higher organisms, phages are host-specific and undergo two different life cycles. In the
lytic stage, the host cell dies, while in the lysogenic stage the viral genome integrates with
host DNA, establishes mutual symbioses conferring adaptation and survival benefits that are
passed on to subsequent cell generations.
Pseudomonas aeruginosa strain PAO1 is a major pathogen infecting cystic fibrosis patients by
forming prolific slimes, or biofilms. The Pf4 phage infects its host PAO1 during biofilm
development when it converts from the lysogenic to lytic stage.
Bacteria suffer environmental stress and undergo adaptive mutation when biofilms become
over-populated and nutrient-poor, switching on the phage lytic cycle and killing biofilm cells.
I am investigating how to use phage in targeted control of biofilms and infections.
My research has identified a protein (repressor C) of PAO1 responsible for viral infection
immunity. Mutations in this protein switch the Pf4 phage to its lytic stage, killing the host.
Furthermore, large deletions of the Pf4 phage genome within PAO1 cause biofilm cell death.
We plan to use these findings to develop biofilm control treatments, especially for preventing
chronic infections with cystic fibrosis patients.
cutting-edge discovery science|