School of Chemistry

Dr Vera Thoss

Image of Dr Vera Thoss
Name
Dr Vera Thoss
Position
Lecturer in Chemistry
Email
vera.thoss@bangor.ac.uk
Phone
+44 (0)1248 38 2516
Location
Chemistry Tower
Website
Plant Chemistry Group

Overview

Summary

There are two strands, environmental and ecological chemistry, and one may ask “What is the difference?” While ecological chemistry addresses processes mediated through specific compounds within ecosystems, environmental chemistry is concerned with the impact of human activities onto the environment.

In depth

Environmental chemistry in the broadest sense is concerned with the cycling of elements through the environment and covers many aspects from mining, over industrial and agricultural production and to waste management. Our quality of life is depended on a broad variety of goods and products, whose chemistry influences their performance and is crucial in determining how to handle the goods at the end of their life. Often environment chemical research is industry-focussed and there are a number of ongoing collaborations with local industries.

Ecological chemistry is concerned with the production and fate of small identifiable molecules produced mainly by plants and their influences on ecological processes. Plants show huge diversity within their natural products and the main aim is to identify the processes influencing production and subsequent environmental fate. Of particular interest has been forestry related research. Previously the Scots pine dominated Caledonian forest, and other conifer-based forestry, has been a focus. Eucalyptus forestry is a recent research addition as it promises large biomass production. From an ecological chemical perspective the understanding of the associated ecology is targeted through phytochemical research.

For both environmental and ecological chemistry the qualitative and quantitative analysis of specific compounds is fundamental. The research conducted is underpinned by the development and application of analytical tools for different environmental matrices.

Previous Career History

  • 2005–2006
    Teaching Fellow Environmental Chemistry, Department of Plant and Soil Science, University of Aberdeen, Scotland
  • 2002–2005
    Post-Doc Chemical Ecology, The Macaulay Institute, Aberdeen, Scotland
  • 2001
    Post-Doc Chemical Ecology, Institute of Vegetation Ecology, University of Umeå, Sweden
  • 2000–2001
    Self-employed Environmental Consultant
  • 1998–2000
    Lectureship Environmental Chemistry, jointly between the School of Chemistry, Trinity College Dublin, Ireland
    and the Department of Chemistry, University of Wales, Bangor, UK
  • 1995–1998
    PhD “Chemical Characterisation of Dissolved Organic Matter” University of Wales, Bangor with Prof. M. S. Baird and Dr. M. A. Lock
  • 1988–1994
    Diplom-Chemikerin “Aluminium Toxicity under Plant Physiological Conditions”, University of Hanover, Germany
  • 1991–1992
    Imperial College International Diploma “Ringopenings of Cyclopropenes”, Imperial College, London, UK

Research

There are two strands, environmental and ecological chemistry, and one may ask “What is the difference?” While ecological chemistry addresses processes mediated through specific compounds within ecosystems, environmental chemistry is concerned with the impact of human activities onto the environment.

Ecological Chemical Research

Research activities centre around plant secondary metabolites (PSM) in particular monoterpenes and phenolics, in other words the compounds that make plants smell nice, look pretty and taste interesting. Questions ask relate to the factors that influence PSM production in the plant and their subsequent environmental fate.

Often the production of PSMs is increased due to an environmental stimulus. For crowberry (Empetrum hermaphroditum) we found that intercepting phenolics prior to entering the humus layer using charcoal resulted in a threefold increase in phenolics production. Because PSMs are not the preferred food source for many organisms, in fact one of their ecological roles has been described as feeding deterrents, they impact onto decomposition mechanisms. For phenolics this translates into an eventually increased concentration in natural waters.
While phenolics affect decomposition and humification, monoterpenes create chemical landscapes meaning their predominant environmental fate is volatilisation. This is beneficial for the plant because monoterpenes negatively impact onto cell membrane processes and thus affect, for example, seed germination in the litter layer. In this respect, the variability of monoterpene composition, or chemodiversity, has been shown to correlate with associated vegetation pattern and host choice.

For ecological chemical research we focus on a specific ecosystem – bluebells and bracken is the current one – and obtain a data on what compounds are present and what their abundance at various phenological stages is. In addition associated ecosystem components, in particular soil and water and air, are analysed to assess whether distinct plant secondary metabolites are translocated from the plant and found in the soil (through rhizodeposition), in water (through leaching) and in air (through volatilisation).

Current projects:

  • Ptaquiloside in bracken
  • Pools and fluxes of monoterpenes in Scots pine

Environmental Chemical Research

Composting, the process of turning green waste into an organic fertiliser, is common practise. During composting, the decomposer community relies on carbohydrates for the supply of energy to metabolism. Which specific carbohydrates come from which types of plants? Does the carbohydrate content decrease during composting? How can we analyse carbohydrates from plant material and compost quantitatively using TMS-derivatisation? These questions form the core of a current research project.

Because you can’t de-invent the wheel, there are half a million tonnes of used car tyres produced in the UK alone. Through continuous reductive distillation, a fuel oil and carbon black is produced. In this industrial collaboration we are aiming at optimising the pyrolysis conditions to increase oil yield and increase the percentage of low boiling hydrocarbons in the oil.

Agriculture depends on the input of fertiliser to increase crop yields. Historically, these fertilisers came from industrial operations, for example slag from foundries which is rich in calcium and phosphate. Over time though fertilisers got ‘purer’ and an off-the-shelve NPK fertiliser just contains those elements. As a consequence the reduction in mineral content of commercially grown fruit and vegetables has been suggested. Our research is aiming to investigate this topic as there is a need for nutritional information on minerals. The atom ratio approach, in which elements are accounted for on an atom per atom basis, has been found particularly suitable for this purpose. For potatoes we found tight atom ratios for Mg/K independent of variety or location of cultivation. Fe/K, however, showed a range of three magnitude suggesting that the iron concentration in potatoes depends more on where they were grown, rather than an essential need.

Analytical Chemistry

The measurement of concentrations and species is underpinning all research efforts described above. For most analytes, the capability exists to ‘find’ these in different matrices. The parts per million concentration range – mg L-1, or mg kg-1, is standard and does not pose any challenges. The parts per billion range – µg L-1 or µg kg-1, requires more skill but has also been achieved regularly. The main highlight there was the quantification of monoterpenes in three week old pine seedlings prior to experimentation. The actual Limit of Detection achieved was 20 pg! Trace analysis – sub ppb concentrations – is technically more challenging and it is hoped to have achieved this soon with our current project on tracing ptaquiloside, the poison in bracken.

A suite of methods is available – tried and tested – that gives us the means to address ecological and environmental problems.

  • Monoterpenoids in plants
  • Hydrocarbon mixtures
  • Fatty acids as FAME (fatty acid methyl esters) in plant material
  • Phenolics (redox-based quantification, interaction with protein)
  • Atom ratio approach (multi-element analysis using ICP-OES)
  • Carbohydrates after sylilation
  • Generally distinct analytes for which the structure is known and a standard is available

Publications

  1. Thoss, V., Murphy, P. J., Marriott, R. and Wilson, T. (2012) Triacylglycerol Composition of British Bluebell (Hyacinthoides non-scripta) Seed Oil. RSC Advances 2: 514–5322.
  2. V.K. Varshney, Amit Pandey, Vera Thoss, Arvind Kumar and H. S. Ginwal (2012). Foliar chemical attributes of the hybrid bred from Eucalyptus citriodora x E. torelliana and its parental taxa, and implications for fungal resistance. Annals of Forest Research 55: 53–60.
  3. Muller-Schwarzy, D and Thoss, V (2008) Defense on the rocks: Low monoterpenoid levels in plants on pillars without mammalian herbivory Journal of Chemical Ecology 34: 1377–1381.
  4. Cooper, R., Thoss, V. and Watson, H. (2007) Factors influencing the release of dissolved organic carbon and dissolved forms of nitrogen from a small upland headwater during autumn runoff events. Hydrological Processes, 21, 622–633.
  5. Stutter, M.I., Lumsdon, D.G. and Thoss, V. (2007) Physico-chemical and biological controls on dissolved organic matter in peat aggregate soil columns. European Journal of Soil Science, 58, 646–657.
  6. Thoss, V., O’Reilly-Wapstra, J. and Iason, G. R. (2007) Intra-specific and phenological variability in monoterpenes of Scots pine (pinus sylvestris) foliage: implications for ecological research. Journal of Chemical Ecology 33:477–491.
  7. O’Reilly, J., Iason, G. R. and Thoss, V. (2007) The role of genetic and chemical variation of Pinus sylvestris seedlings influencing slug herbivory. Oecologia 152: 82–91.
  8. Kennedy S., Cameron, A., Thoss, V. and Wilson, M. (2006) Role of monoterpenes in Hylobius abietis damage levels between cuttings and seedlings of Picea sitchensis. Scandinavian Journal of Forest Research 21: 340–344.
  9. Pakeman, R.J., Beaton, J.K., Thoss, V., Lennon, J.J., Campbell, C.D.,
    White, D. & Iason, G.R. (2006) The extended phenotype of Scots pine (Pinus sylvestris) structures the understorey assemblage. Ecography 29: 451–457.
  10. Thoss, V. and Byers, J. A. (2006) Monoterpene chemodiversity of ponderosa pine in relation to herbivory and bark beetle colonization. Chemoecol. 16: 51–58
  11. Duncan, A. J., Reid, S., Thoss, V. and Elston, D. A. (2005) Browse selection in response to simulated seasonal change in diet quality through post-ingestive effects. J. Chem. Ecol. 31: 729–744.
  12. Iason, G. A., Lennon, J. J., Pakeman, R., Thoss V., Beaton, J. and Sim, D. (2005) Chemical diversity within individual Scots pine trees determines biodiversity of associated ground flora. Ecol. Lett. 8: 364–369.
  13. Thoss, V., Shevtsova, A. and Nilsson, M.-C. (2004) Environmental manipulation treatment effects on the reactivity of water-soluble phenolics in a subalpine tundra ecosystem, Plant Soil 259: 355–365.
  14. Thoss, V., Baird, M. S., Lock, M. A. and Courty, P. V. (2002) Quantifying the phenolic content of freshwater using simple assays with different underlying reaction mechanisms, J. Env. Monit., 4: 270–275.
  15. Gunnlaugsson, T., Nieuwnhuyzen, M., Richard, L. and Thoss, V. (2002) Novel sodium-selective fluorescent PET and optically based chemosensor: towards Na+ determination in serum, J. Chem. Soc. Perkin Trans., 2: 141–150.
  16. Gunnlaugsson, T. Nieuwnhuyzen, M. Richard, L. and Thoss, V. (2001) A novel optically based chemosensor for the detection of blood Na+, Tetrahedron Lett., 42: 4725–4728.
  17. Thoss, V., Baird, M. S. and Lock, M. A. (2000) The development of a chemical ‘fingerprint’ to characterise dissolved organic matter in natural waters, J. Env. Monit., 2: 398–403.
  18. Baird M. S., Aldulayymi J. R., Rzepa H.S. and Thoss, V. (1992) An unusual example of stereoelectronic control in the ring-opening of 3,3-disubstituted 1,2-dichlorocyclopropenes, J. Chem. Soc. Chem. Comm. 18: 1323–1325.

Book chapter

Thoss, V (2010) British Bluebells: The potential of using a protected species as a provider of fine chemicals to enhance its conservation in Woodlands: Ecology, Management and Conservation (Editor Erwin, B Wallace). Nova Science Publisher

Research Group

Group Members

Current PhD students

Dotsha Raheem “Poisoned soils: Chemical assessment of Bluebell and Bracken climax vegetation”
Abdulahi Usman “Extraction, Isolation and Identification of Limonoids in Trichilea emetica

Current MPhil students

Ufuomaefe Steve Oghoje “Remediation approached for oil polluted soils using locally sourced materials”

Image of Vera Thoss and her Research groupCurrent MSc students

David Martin “Analysis of manufacturer topsoil”
Victor Oghogho Ebuele “Determination of Phosphorus in environmental matrices”
Michael Beke “Investigation in the effect of organic matter on retention of hydrocarbon pollution in soils”
Ali Alshmrani “Analysis of hydrocarbon mixtures”
Jawameer Hama “Analysis of chemical components in Walnuts”

Group 2007: Abdo, Vera, Suad and Tareg

Past MRes student

Owain Atkins “Increasing horse power using renewable resources”

Past MSc Students

  • Matt Clewley (2011) Enzymatic extraction of pulp oil from sea-buckthorn berries. MSc Thesis, Bangor University
  • Ralph Dutton (2011) How to make topsoil artificially using products derived from waste utilisation. MSc Thesis, Bangor University *
  • Andrew Halliwell (2011) The production and usage of essential oils. MSc Thesis, Bangor University
  • Liam Nelligan (2011) An investigation into the carbohydrates from plant extracts. MSc Thesis, Bangor University *
  • Edward Parker (2011) Bioactive components in herbal preparations for the treatment of horses. MSc Thesis, Bangor University *
  • Fabian Schweickert (2011) Finding further uses for the residue from anaerobic digestion. MSc Thesis, Bangor University
  • Theetso Motsamai (2010) Application of sequential extraction procedure for determination of copper in an old mine site: Parys Mountain. MSc Thesis, Bangor University *
  • Ifan Richard (2010) Chemical characteristics of vegetable oil samples of different ages. MSc Thesis, Bangor University
  • Owain Atkins (2010) Analysis of supplementary feed for horses. MSc Thesis, Bangor University
  • Assad Elmahjoubi MSc Env. Chem. 2009Analysis of Sea-Buckthorn (Hyppophae rhamnoides) Derived Products and the Effect of Processing onto Specific Metabolite Groups
  • Hosea Mukunda Litiku MSc Env. Chem. 2008Development and Application of Plant Screening Methodologies for Biochemically Related Compounds *
  • James Ainsworth MSc Env. Chem. 2008Do They Stay or Do They Go? The Fate of Individual Carbohydrates During Composting
  • David Whiting MSc Env. Chem. 2008Bracken Phytochemistry: How Toxic is the World’s Most Common Fern? *
  • Tareg Ahmed MSc Env. Chem. 2007Waste not, Want no: New Products from Old Tyres
  • Abdussalam Alghazewi MSc Env. Chem. 2007Investigation in the Environmental Fate of Refinery Products in Desert Environments *
  • Suad Ghlayee MSc Env. Chem. 2007Development of a Multi-Element Method to Determine the Molar Ratios of Essential Nutrients in Different Matrices
  • M. Jones MSc Env. Chem. 2000The Effect of DOM on Extracellular Enzyme Activity in Aquatic Environments
  • Nicola O’Gorman MSc Env. Chem. 2000An Investigation into the Variation of Plant-Derived Phenolics in Sampling Sites Across North Wales
  • Ludovic Richard MSc Res. 2000Synthesis of Novel Optically Based Chemosensors: Towards Sodium Determination in Freshwater and Blood
  • Ian Washbourne MSc Env. Chem. 1999Seasonal Variation of Plant-Derived Phenolics *
  • Mark Brunero MSc Env. Sc. 1999Investigation into the pre-concentration and Analysis Techniques for Monomeric Phenolics In Water
  • Philip Courty MSc Env. Chem. 1998Phenols: An Assessment of a Method for the Determination of Monomeric Phenolic Compounds, and their Separation using Chromatography*

MSc with distinction indicated by *

Past final year project students

  • Anna Zelmer 2012 Supercritical CO2 to separate cashew nut shell liquer (with Ray Marriott)
  • Christopher Rayner 2012 Development of a phosphorus sensor (with Chris Gwenin)
  • Sam Roulstone 2012 Analysis of woodash to trap heavy metals
  • Victoria Asquith 2012 Investigation into dissolution of woodash
  • Prativa Chhetri 2012 Assessment of the yield of essential oils in Sitka spruce
  • Susan Moss 2012 Seasonal variation of monoterpenes in Scots pine
  • Toby Vye 2010 Shikimic acid from Sitkas spruce forestry brush
  • Will Snape 2010 Wood ash analysis
  • Matt Evans 2009 Eucalyptus Phytochemistry
  • Rebecca Harmsworth 2009 Essential Oil Production in Coniferous Forests
  • Emma Ingham 2009 Fatty Acid Content of Coffee
  • Tom Carter 2009 Tracing Hydrocarbon Pollution Sources

Collaborations

Phenolic acids in mulch and compost samples

Collin Scantlebury and Dr Emma Smith, Department of Biological and Chemical Sciences, University of West Indies, Cave Hill Campus, Bridgetown, Barbados

Trichillia emetica and cacao protection

Dr. Godfred Darko, Department of Chemistry, Kwame Nkrumah University of Science & Technology, Kumasi, Ghana

Petroleum chemistry

Dr Festus Adebiyi, Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria

Eucalyptus breeding

Dr. V. Varshnay, Chemistry Division, Forest Research Institute, Dehra Dun, India

Bracken Phytochemistry

Prof. H. C. B Hanson, Department of Natural Sciences, Soil and Environmental Chemistry, Faculty of Life Science, University of Copenhagen, Denmark

Prof. R. Pakeman, The Macaulay Institute, Aberdeen, Scotland

Prof. Rob Marrs, Applied Vegetation Dynamics, School of Biological Sciences, University of Liverpool, Great Britain

Bluebell Phytochemistry

Prof. R. Nash, Phytoquest, Plas Gogerddan, Aberystwyth, Wales

Herbivory and Pulegone toxicity

Prof. D.-M. Müller-Schwarze, State University of New York, College of Environmental Science and Forestry

Phenolics in Crowberry

Prof. Marie-Charlotte Nilsson, Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden

Chemodiversity and Bark Beetles

Prof. John Byers, USDA, Agricultural Research Services, Phoenix, Arizona, USA

Caledonian Forests

Dr. G. Iason (project leader), The Macaulay Institute, Aberdeen, Scotland

Negative post-ingestive consequences

Dr. A. Duncan, The Macaulay Institute, Aberdeen, Scotland

Slug Herbivory

Dr. J. O’Reilly-Wapstra, School of Plant Science, University of Tasmania, Australia

Sitka Spruce Forestry

Drs. M. Wilson and A. Cameron, Plant and Soil Science, University of Aberdeen, Scotland

Sodium Sensor

Dr. T. Gunnlaugson, Department of Chemistry, Trinity College Dublin, Ireland

DOM Fingerprinting

Dr. M. Lock, School of Biological Sciences, Bangor University, Wales
Drs. M. Stutter and D. Lumbsdon, The Macaulay Institute, Aberdeen, Scotland
Dr. R. Cooper, The Macaulay Institute, Aberdeen, Scotland

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