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Professor Dennis Taylor
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Dennis Taylor Head of group |
Thomas Avery Postdoctoral Research Fellow |
Nichole Cain PhD |
Peter Valente PhD |
Ben Noll |
James Lienert Honours (24 Unit) |
Kerry Dungey Honours (24 Unit) |
Samuel Hambour Honours (12 Unit) |
Sarah MadiganHonours (24 units half time) |
Petros Kneknopoulos Masters (12 units) |
Research Programme Highlights
Understanding the role of hydrogen peroxide in grape and vine tissues.
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In addition to its role in oxidative damage, hydrogen peroxide (H2O2) is emerging as a key signalling molecule generated by plants in response to both biotic and abiotic stresses such as drought, UV-radiation, ozone, high and low temperatures and pathogen attacks. In green plants, H2O2 is produced at high flux rates in the chloroplasts and in the mitochondria via electron transport. Furthermore there are a number of other enzymes in plant tissues that are capable of producing significant amounts of H2O2, including peroxidases, NADPH oxidases and oxalate oxidases. H2O2 is moderately reactive and is a relatively long-lived molecule that can diffuse across membranes and inactivate enzymes by oxidising thiol groups. It is clear that higher levels of hydrogen peroxide will result in increased levels of oxidised biomolecules, which ultimately affect final wine quality. We are carrying out a detailed analysis of the hydrogen peroxide levels within grapes and vine tissues all the way from but burst to final wine and correlating this with wine quality. Collaborators: Chris Rogers (Viticulturist, St Hallet winery) and Russel Johnstone (Viticulturist, Orlando winery). |
New degradable botrytis fungicides.
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Botrytis bunch rot is caused by the fungus Botrytis cinerea and is a widespread disease of grapevines in Australia. In some seasons, district crop losses can exceed 30-40%, while entire crops can be lost in disease-prone vineyards. Grapes presented at the weighbridge with 3-6% visible rot generally receive a price penalty with some loads being rejected when bunch rot exceeds 6-10%. This also damages the reputation of the vineyard with business lost through botrytis difficult to regain. Consequently we have embarked on the synthesis of a large library of 1,2-dioxines (endoperoxides) and related compounds and assessing their antifungal activity through in-vitro assay systems. If successful, these fungicides will be able to be used by grape growers up until the day of harvest, will have little to no residue in wine and will allow for further control of vineyard management practices. Collaborators: Chris Rogers (Viticulturist, St Hallet winery) and Russel Johnstone (Viticulturist, Orlando winery), Dr Ian Dry (CSIRO Plant Industry); Dr Trevor Wicks (SARDI Horticulture Pathology). |
Sterol endoperoxides.
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One of the groups of natural steroids with unexplained biological functions are the steroid endoperoxides. Since the biosynthesis of steroids required a large expenditure of energy and the presence of a considerable number of special enzymes, it is difficult to expect that living organisms would produce substances that are not at all necessary to them. For this reason, an elucidation of the exact purpose of the formation of sterol endoperoxides is one of the necessary conditions for understanding the mechanisms of the functioning of biological systems. Ergosterol endoperoxide has been widely found in the fungi, plant and animal kingdoms. Whilst there have been no reports of its presence in vines or berries it has been shown to exist in Botrytis and yeast cultures. How it is formed is not known but may involve singlet oxygen either in a photochemical manner or by enzyme assistance. Consequently we plan to ascertain the reasons why ergosterol endoperoxide is produced by Botrytis and to search for its presence during fermentations and also in the final sweet wines. Collaborators: Dr Ian Dry (CSIRO Plant Industry); Certain wineries and grape growers. |
Unravelling the wine metabolome.
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The wine metabolome equates to the complete chemical makeup of wine, and includes compounds originating from the grape (as influenced by variety, rootstock, climate and viticultural practices), microorganisms occurring in the vineyard and all stages of the winemaking process, additives, as well as maturation and processing treatments. The importance of each and every wine constituent to wine flavour and aroma is not known, but clearly many of these compounds, and typically not the most predominant examples, are critical to the way in which consumers perceive a wine. As case-studies, we plan to determine the influence of variety (e.g. Shiraz vs Chardonnay), climate (‘hot’ vs ‘cold’) and yeast strain on juice and/or wine composition.
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Control of foliar diseases in horticulture using milk components.
Fungal diseases, such as powdery mildew and botrytis grey mould, have the potential to cause considerable losses in horticultural crops. Chemical fungicides, some of which are broad-spectrum biocides potentially harmful to human health, are applied routinely in disease management. Milk and whey, which can damage powdery mildew fungi, offer alternatives to conventional fungicides. Identification of the components of milk, which damage fungi, and their mechanisms of activity, will facilitate the development of environmentally sustainable strategies for management of fungal diseases in Australian horticulture. This will have particular benefits for personnel who regularly apply fungicides in glasshouses.
Collaborators: Dr Eileen Scott (Ag, Food and Wine); Professor Otto Schmidt (Ag, Food and Wine), Dr Michelle Rowney (MG Nutritionals), Dr Paul Grbin (Ag, Food and Wine), Dr Trevor Wicks (SARDI).
Researchers: Upcoming PhD student
Project Suitability: Suitable for PhD Students only.
Positions Available: Industry priority PhD scholarship available now.
Characterisation of lees and novel uses for yeast lees to create new wine styles.
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Yeast lees are often incorporated in the ageing of wine with the observed benefits of flavour complexity and/or enhanced physical or textural properties. Two wine styles where this is widely used are bottle fermented sparkling wine and barrel fermented Chardonnays. Grand cru white wines are traditionally aged sur lies. However, this technique has increased in popularity for aging of red wines in recent years and is still considered in its experimental stage with little scientific foundation. This method involves aging wines in the presence of their lees (yeasts from alcoholic fermentation and organic residue from the must). The chemical composition of lees changes during the storage of wines. Autolysis is the term used to describe the reactions that occur in the non-viable yeasts (yeast that have lost their ability to multiply) present in lees. The autolysis of yeasts is defined as the hydrolysis of intracellular biopolymers by the endohydrolases induced by cell death, followed by the formation of low molecular weight products. Autolysis occurs slowly as wines age, and the molecules released may increase or improve the qualities and potentialities of certain wines, eg, champagne, sparkling and white wines. Thus we have developed a variety of research projects aimed at identifying the key organics released into the wine upon exposure to lees and autolysis enzymes and correlating this with the sensory properties of the wines. Collaborators: Dr Sue Bastian (Ag, Food and Wine) Dr Chris Ford (Ag, Food and Wine), Rob Lee (Enzyme Solutions); Hylton McLean (Sparkling Winemaker – Orlando Wines). |
Reactive oxygen species and their role in wine production.
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Oxidation reactions involving biomolecules found within grape vine tissues, berries, during the fermentation process and wine storage will have an effect on the chemical and sensory profile of wines. While oxidation is a long-standing problem in winemaking, a definitive understanding of its chemical mechanisms is lacking and as such an understanding could allow us to better predict and control wine aging. Consequently a research project exists to carry out the first systematic study on the effects of ROS on biomolecules not only found in wine but also within the berries and other components of vines e.g. leaves and to track their formation and consumption throughout the entire process.
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Understanding the role of organic peroxides on plant root growth.
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Reactive oxygen species (ROS) are known to regulate, or have been hypothesised to play a role in, a whole host of plant signalling pathways including germination, plant-pathogen defence responses, cell-wall elongation, cell development, stomatal closure, suberisation or lignification and senescence. We have found that organic peroxides have a dramatic effect on root growth and are currently carrying out structure activity relationships (chemical genomics approach) to pin down the mode of action. Collaborators: Dr Matt Gilliham (Ag, Food and Wine), Dr Amanda Able (Ag, Food and Wine). |
Aroma compounds in grape and wine – part 1.
The study of wine is a very difficult task due mainly to its chemical complexity and variability. A typical wine will have in the vicinity of one thousand volatile components; however the vast majority of these will be either odourless or present at levels well below their detection threshold. In addition to the volatile compounds present in any wine, the situation is further complicated by the presence of a vast pool of involatile compounds, many of which are glycosidic in nature - an organic molecule (aglycone) attached to one or more sugar units. These sugars can be cleaved either enzymatically (by action of wine microorganisms or addition of exogenous enzyme preparations) or hydrolytically due to the acidic nature of wine (over time as the wine matures) to liberate the free organic molecule which might then contribute to the perceived aroma. Consequently, the proper investigation of the aroma and flavour of wine needs to address both the aroma compounds already present, as well as the potential for production of further aroma compounds from their involatile precursors. A joint project with the AWRI now exists to identify, isolate and characterise the hydrolytic behaviour of glycoconjugated precursors to aroma compounds in grapes and wine.
Collaborators: Dr Gordon Elsey (AWRI), Dr Mark Sefton (AWRI).
Researchers: None
Project Suitability: Suitable for Honours, Masters and PhD students.
Positions Available: YES available now.
Aroma compounds in grape and wine – part 2.
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In the past, little attention has been paid by wine chemists to the stereochemical questions which arise; many important or potentially important aroma compounds can exist as more than one stereoisomer (compounds that have effectively the same structure, but which differ in their 3D spatial arrangement). Methods which quantify the broad structure but which do not address the individual stereochemical composition of wine components can only be of limited value to the industry. Among the compounds we wish to prepare are the monoterpene furanoid oxides, which are formed both in the grape and during wine aging. They have been commonly reported in the literature, but sensory analysis has not been conducted, and so their actual contribution to wine aroma is unknown. Consequently we have initiated a new research program on the application of new methodologies to the synthesis and sensory evaluation of enantio-pure grape and wine constituents, particularly focussing on the furanoid oxides. Collaborators: Dr Gordon Elsey (AWRI). |
The control of berry ripening.
The timing and progress of berry ripening are important parameters that influence harvest date, ripening synchronization and berry composition which in turn are important for winemaking logistics and wine style and quality. Unlike climacteric fruit such as tomatoes, where the control of ripening by ethylene is well understood, the role of plant growth regulators (PGRs) during ripening in non-climacteric fruit, such as grape berries, has not yet been clearly defined. PGRs act to coordinate both developmental changes in gene expression (as occurs in ripening) and the response to external cues such as water stress. A better understanding of this process will offer a means of usefully manipulating berry composition and the timing and synchronicity of ripening. Consequently a joint project exists with CSIRO to investigate the role of carotenoid derivatives in the control of ripening and berry flavour development within grapes.
Collaborators: Dr Chris Davies (CSIRO Plant Industry), Dr Paul Boss (CSIRO Plant Industry).
Researchers: None
Project Suitability: Suitable for Honours, Masters and PhD students.
Positions Available: Yes.
Cyclodextrins as new wine fining agents.
Cyclodextrins are a class of cyclic oligomeric sugars formed naturally and synthetically by the action of selected microorganisms on starch. Various forms of cyclodextrins exist. The main interest from a scientific point of view is their ability to for inclusion complexes with other molecules and their ability to modify the organoleptic qualities of foodstuffs is well known yet there are no reported uses in the wine industry. Consequently we are exploring the use of cyclodextrins to mask or remove common taints found in wine.
Collaborators: Dr Sue Bastion (Ag, Food and Wine), Dr Paul Bowyer (Lafforte Tecnologie), Prof. Steve Lincoln (Chemistry).
Researchers: Sarah Madigan (Honours student, part-time 24 units)
Project Suitability: Suitable for Honours, Masters and PhD students.
Positions Available: Yes.
Improved control of wine phenolic profiles.
Understanding the fundamental chemical reactivity and interconversions of wine phenolics is one of the keys to improved control of wine phenolic profiles. This project will investigate the functional effect on tannins of incorporating common wine phenolics into their structure. The incorporation of compounds such as anthocyanins (to form pigmented polymers) and flavan-3-ols (to give other tannins) is well known, but little consideration has been given to the incorporation of compounds such as flavonols. Flavonols are well known sun exposure markers, are in relatively high concentration in Australian red wines. These compounds and others will be incorporated into tannins using synthetic organic chemistry techniques in order to generate compounds of defined structure. These compounds will then be investigated for their basic physicochemical properties, spectral properties, reactivity and their sensory properties.
Collaborators: Dr Paul Smith (AWRI), Dr David Jeffery (AWRI), Assoc. Prof. Marcus Herich (AWRI).
Researchers: None
Project Suitability: Suitable for Honours, Masters and PhD students.
Positions Available: Yes available now.
Understanding the roles of quinonoidal intermediates in the formation of wine phenolics.
Understanding the fundamental chemical reactivity and interconversions of wine phenolics is one of the keys to improved control of wine phenolic profiles. This project will investigate the roles of quinonoidal intermediates in the formation of wine phenolics. Quinones are well known intermediates in the oxidation, rearrangement and recombination of wine phenolics, but the chemistry associated with these interconversions is still poorly understood. Formed by free radical mechanisms and enzymic mechanisms, quinones are attractive targets for myriad nucleophilic compounds present in wine. Such compounds include other phenolics and also volatile flavour and aroma compounds; reactions of these molecules with quinones will have an effect on organoleptic properties. This project will investigate the formation, measurement of quinones and the reactivity of quinones with other important wine molecules.
Collaborators: Dr Paul Smith (AWRI), Dr David Jeffery (AWRI), Assoc. Prof. Marcus Herderich (AWRI).
Researchers: None
Project Suitability: Suitable for Honours, Masters and PhD students.
Positions Available: Yes available now.
A special thankyou
The Taylor research group would like to thank the following wineries who have generously supplied wine samples for research.
- d’Arenburg
- Woodstock
- Scarpantoni Estate
- Yalumba
- Jacobs Creek
- Grant Burge
Prizes and Awards
Key Papers
- Greatrex, B. W.; Jevric, M.; Kimber, M. C.; Krivickas, S. J.; Taylor, D. K.; Tiekink, E. R. T. A Novel Bis-Lactonisation of Naphtho- and Phenanthro-1-2-Dioxines with Malonate Nucleophiles. Synthesis., 2003, 5, 668-673.
- Adcock. W.; Trout, N. A.; Vercoe, D.; Taylor, D. K.; Shiner, Jr, V. J.; Sorensen, T. S. Solvolysis of (Z)-5-Trimethylstannyl 2-Adamantyl p-Bromobenzenesulfonate: Mechanistic Implications of a Record-Breaking Secondary ?-Deuterium Kinetic Isotope Effect for an SN1 Substrate. J. Org. Chem., 2003, 68, 5399-5402
- Greatrex, B. W.; Kimber, M. C.; Taylor, D. K.; Tiekink, E. R. T. A Novel Synthesis of Functionalised Tetrahydrofurans by an Oxa-Michael / Michael Cyclisation of ?-Hydroxyenones. J. Org. Chem., 2003, 68, 4239-4246.
- Greatrex, B. W.; Jenkins, N. F.; Taylor, D. K. Base and Co(II)-Catalysed Ring-Opening Reactions of Perhydrooxireno[2,3-d][1,2]dioxines: An Efficient Route to 4-Hydroxy-2,3-epoxy-ketones. J. Org. Chem., 2003, 68, 5205-5210.
- T. D. Avery, B. W. Greatrex, A. D. Humphries, M. Kalkanidis, E. N. Fox, N. Klonis, I. G. Macreadie, P. I. Macreadie, D. K. Taylor, E. R. T. Tiekink, L. Tilley. Novel Endoperoxide Antimalarials: Synthesis, Heme Binding and Antimalarial Activity. J. Med. Chem., 2004, 47, 1833-1839.
- Greatrex, B. W.; Taylor, D. K. Triphenylphosphine-Induced Ring Contractions of 1,2-Dioxines. J. Org. Chem., 2004, 69, 2577-2579.
- Greatrex, B. W.; Taylor, D. K.; Tiekink, E. R. T. A Domino Ring-Opening / Epoxidation of 1,2-Dioxines. J. Org. Chem., 2004, 69, 2580-2583.
- Greatrex, B. W.; Taylor, D. K. Ring-Opening of Unsymmetrical 1,2-Dioxines Using Cobalt(II) Salen Complexes. J. Org. Chem., 2005, 70, 470-476.
- Jevric, M.; Taylor, D. K.; Greatrex, B. W.; Tiekink, E. R. T. DDQ Induced Oxidative Cyclisations of 1,2-Dihydronaptho[2,1-b]furans. Tetrahedron, 2005, 61, 1885-1891.
- Avery, T. D.; Caiazza, D.; Culbert, J.; Taylor, D. K.; Tiekink, E. R. T. 1,2-Dioxines Containing Tethered Hydroxyl Functionality as Convenient Precursors for Pyran Synthesis. J. Org. Chem., 2005, 70, 8344-8351.
- Macreadie, P. I., Avery, T. D.; Greatrex, B. W.; Taylor, D. K.; Macreadie, I. G. Novel Endoperoxides: Synthesis and Activity against Candida Species. Bioorg. Med. Chem. Lett 2006, 16, 920-922.
- Avery, T. D.; Culbert, J. A.; Taylor, D. K. The First Total Synthesis of Natural Grenadamide. Org. Bio. Chem., 2006, 4, 323-330.
- Brown, R, C.; Elsey, G. M.; Taylor, D. K. Utilization of a 1,2-dioxine for the Synthesis of the Four Possible Stereoisomers of Oak Lactone. Org. Lett. 2006, 8, 463-466.
- Brown, R. C.; Elsey, G. M.; Sefton, M. A.; Taylor, D. K. An aroma detection threshold determination of all four possible stereoisomers of oak lactone in a white and a red wine. Aust. J. Grape Wine Res. 2006, 12, 115-118.
- Robinson, T. V.; Taylor, D. K.; Tiekink, E. R. T. Osmium Catalyzed Dihydroxylation of 1,2-Dioxines: A New Entry for Stereoselective Sugar Synthesis. J. Org. Chem., 2006, 71, 7236-7244.
- Avery, T. D.; Macreadie, P. I.; Greatrex, B. W.; Robinson, T. V.; Taylor, D. K.; Macreadie, I. G. Design of Endoperoxides with anti-Candida Activity. Bioorg. Med. Chem. 2007, 15, 36-42.
- Crespo, M. P.; Avery, T. D.; Hanssen, E.; Fox, Emma.; Robinson, T. V.; Valente, P.; Taylor, D. K.; Tilley, L.. Artemisinin and a Series of Novel Endoperoxide Antimalarials Exert Early Effects on Digestive Vacuole Morphology, Antimicrobial Agants and Chemotherapy, 2008, 52, 98-109.
- Macreadie, I. G.; Avery, T. D.; Robinson, T. V.; Macreadie, P.; Barraclough, M.; Taylor, D. K.; Tiekink, E. R. T. Design of 1,2-dioxines with anti-Candida activity: Aromatic substituted 1,2-dioxines, Tetrahedron. 2008, 64, 1225-1232.
- Avery, T. D.; Greatrex, B. W.; Pedersen, D. S.; Taylor, D. K.; Tiekink, E. R. T. A Concise Route to ?-Cyclopropyl Amino Acids Utilizing 1,2-Dioxines and Stabilized Phosphonate Nucleophiles. J. Org. Chem., 2008, accepted.
Supporting Crystallographic Publications:
- Fallon, G.; Greatrex, B. W.; Kimber, M. C.; Taylor, D. K. Crystal structure of (±)-[(2S,3S)-3-(hydroxymethyl)oxiran-2-yl](phenyl)-methanone, C10H10O3. Z. Krist., 2003, 218, 561-562.
- Greatrex, B. W.; Kimber, M. C.; Taylor, D. K.; Tiekink, E. R. T. Crystal structure of (±)-(2R)-2-[3S,4S,5S)-4-benzoyl-5-hydroxymehtyl-4-methyltetrahydro-3-furanyl]-1-phenylpropan-1-one, C22H24O4. Z. Krist., 2003, 218, 63-64.
- Greatrex, B. W.; Kimber, M. C.; Taylor, D. K.; Tiekink, E. R. T. Crystal structure of (±)-{[2S,3S,4S)-3-benzoyl-3-methyl-4-[(1S)-1-methyl-2-oxo-2-phenylethyl]tetrahydro-2-furanyl}methyl benzoate, C29H28O5. Z. Krist., 2003, 218, 65-66.
- Pedersen, D. S.; Taylor, D. K.; Tiekink, E. R. T. tert-Butyl N-(3,6-dihydro-1,2-dioxin-4-ylmethyl)carbamate. Acta Crystallographica E63, 2007, o4301.
- Robinson, T. V.; Taylor, D. K.; Tiekink, E. R. T. (+)-(1R,2S,2S,4S)-2-Chloro-3-(phenyl-selanyl)cyclohexane-1,4-diol. Acta Crystallographica E63, 2002, o3350.
- Culbert, J. A.; Taylor, D. K.; Tiekink, E. R. T. (+)-(5S)-5-[(1S)-2-Benzoyl-1-hydroxy-ethyl]-1,2,3,4-tetrahydrofuran-2-one. Acta Crystallographica E63, 2007, o3349.
- Avery, T. D.; Greatrex, B. W.; Taylor, D. K.; Tiekink, E. R. T. (+)-(1R,2S,3R)-2-[(Benzyloxycarbonyl)-methyl]-3-phenylcyclopropanecarboxylic acid. Acta Crystallographica E63, 2007, o3344.
Past Members/Students: Where are they now?
Coming soon!
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