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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
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