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Title: Synthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plants
Author: Wood, Barry Alan
ISNI:       0000 0004 2710 4635
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2011
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This thesis describes research based around phytochelatins (PCs), plant peptides synthesised during the influx of metal(loid)s such as arsenic.  Development of synthetic strategies for production of PCs and a bromine-based thiol tag were pursued.  The role of PCs in the arsenic translocation system in plants was monitored firstly by statistical analysis, then by monitoring arsenic translocation of L-BSO-poisoned and mutant plants. Whilst protected PC2 was synthesised in good yield, subsequent isolation of deprotected PC2 was not achieved via SEC or RP chromatography.  Statistical analysis showed that differential transport of iAs(V) and DMA(V) in planta between two plant groups was not due to PC/As(III)-PC speciation difference, but this was far from conclusive.  Plants exposed to iAs(V) and the PC synthase inhibitor L-BSO showed increased arsenic translocation with decreasing As(III)-PC levels, but the trend was not statistically significant.  Analysis of Arabidopsis thaliana mutants with differing PC levels confirmed that arsenic translocation increased with reduced PC and As(III)-PC complex levels.  HR-ICP-MS quantified unbound PC species on m/z 32 (S+), whilst HR-ESI-MS identified the (GS)3-As(III) complex for the first time in vivo.  Whilst significant levels of iAs(III) and PC2 exist within seaweeds, no As(III)-PC complex formation was observed.  This indicates a transient role, if any, for PCs during the in vivo detoxification of arsenic within seaweeds.  The development of a thiol tag based upon a polybrominated-pyrrole moiety was unsuccessful, owing to the greater-than-anticipated complexity of the chemistry exhibited by pyrrole.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available