Page 9 - PERIODIC Magazine Issue 5

In hypoxic (oxygen deficient) conditions, alternative
anaerobic metabolism is activated in plants which allows
them to survive for short periods of time. This stress
response system is controlled by proteins known as the
Ethylene Response Transcription Factors (ERFs), In the
presence of O the ERFs are degraded in an oxidation
2
reaction catalysed by a group of enzymes known as Plant
Cysteine Oxidases (PCOs). As O levels decrease (e.g.
2
under flood conditions), the degradation reaction becomes
less prevalent which stabilises the ERFs, allowing them to
The group also showed that the bio-pixels displayed rapid
reversibility or ‘on-off’ behaviour and could be calibrated trigger anaerobic metabolism. Scientists have known about
to respond to greyscale images by producing a range of the stress response since 2014 but did not understand
electrical signal strengths. the details of the mechanism at the molecular level. Mark
White from the Flashman group used mass spectrometry
The group is now investigating how the device interacts to validate the degradation mechanism and confirm the
with living tissues by identifying which cells can be product of the oxidised ERFs. The results are important for
stimulated by the electrical signals and how they respond. developing methods for enhancing the stability of the ERFs
The group also proposes that the artificial retina will have a in crops to promote a quicker, more effective response to
reduced risk of immune rejection as it is completely acellular hypoxia.
and made from bio-compatible materials.
*Vanessa Restrepo Schild, Dr Michael Booth Further research is now being carried out to understand
more precisely how the PCO enzymes work to allow for
Read more: efficient, targeted inhibition of their activity to improve the
Light-Patterned Current Generation in a Droplet Bilayer stability of ERFs by preventing their degradation.
Array. V Restrepo Schild et al., Scientific Reports 7, 46585
(2017) doi:10.1038/srep46585
See also: http://www.ox.ac.uk/news/2017-05-04-oxford-
student-creates-first-synthetic-retina

Flashman Group
Improving food security

The damage and eventual
death inflicted on crops during
time of flood due to prolonged
submergence has major
implications for food security.
Research carried out by the
Flashman group. has led to
significant developments
in understanding the stress
response system in plants due Read more:
to a lack of oxygen in flood Plant cysteine oxidases are dioxygenases that directly
events. This research aims enable arginyl transferase-catalysed arginylation of N-end
to develop a way forward in rule targets, Mark D White et al., Nature Communications
improving food security via 8, 14690 (2017), doi:10.1038/ncomms14690
genetic modification of crops
to increase their survival See also: http://www.ox.ac.uk/news/science-blog/
rates under these adverse manipulating-plant-enzymes-could-protect-crops-flooding
conditions.

9
Periodic
The Magazine of the Department of Chemistry