
Overview
Background
Professor Mary Fletcher is a natural product organic chemist, and led the Natural Toxin group within the Centre for Animal Science, Queensland Alliance for Agricultural and Food Innovation (QAAFI) 2010-2024,before being appointed Emeritus Professor in 2024. She previously worked as a research chemist at both The University Queensland and Queensland Primary Industries (Biosecurity Queensland), before joining the Queensland Alliance for Agricultural and Food Innovation in 2010. Prof Fletcher's current interest focuses on bioactives that reduce enteric methane and the application of slow release delivery systems appropriate to rangeland grazing systems. Prof Fletcher has an industry recognised expertise as an applied organic chemist with a specialist interest in the identification and analysis of natural toxins and other bioactives in a range of plants, fungi and agricultural products. Such toxins and bioactives can affect both human and animal health posing risks to livestock production, food safety and market access.
Prof Fletcher is also an Affiliate Professor in the School of Chemistry and Molecular Biosciences (http://www.scmb.uq.edu.au/index.html), and an Affiliated Scientist at the Biosciences eastern & central Africa-International Livestock Research Institute (BecA-ILRI) Hub in Nairobi, Kenya (http://hub.africabiosciences.org/).
Prof Fletcher is a Fellow of the Royal Australian Chemical Institute and in 2016 was elected President of the Queensland Branch of the Royal Australian Chemical Institute (http://www.raci.org.au/branches/qld-branch).
Availability
- Emerita Professor Mary Fletcher is:
- Not available for supervision
Fields of research
Qualifications
- Bachelor of Science, The University of Queensland
- Bachelor (Honours) of Chemistry, The University of Queensland
- Doctor of Philosophy, The University of Queensland
Research interests
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Slow release inserts to deliver bioactive compounds that reduce enteric methane
Methane emissions from the beef cattle sector accounts for ~7% of Australia’s greenhouse gas emissions. This collaborative UQ-DAF project brings together a team of interdisciplinary scientists and applies novel technologies to progress the industry goal of achieving a carbon neutral beef industry by 2030. The synthetic feed additive 3 nitrooxypropanol (3-NOP) has shown promise in enteric methane mitigation. This compound targets the nickel enzyme methyl-coenzyme M reductase (MCR) in rumen archea, thereby inhibiting the last step of CH4 formation by reversibly oxidizing the nickel cofactor from Ni(I) to Ni(II). Applications to date have necessitated daily dosing regimes relevant mostly for intensive cattle systems, and this project seeks to provide alternate delivery mechanisms to enable application in extensive systems. In extensive grazing systems, most supplements are normally delivered through licks, with little or no control of intake by individual animals. Many methane mitigating active-agents including 3-NOP are required to be delivered consistently to the rumen to be effective. This project seeks to deliver a novel rumen insert for controlled release of active-agents to provide a sustained slow-release dose. Such technology avoids any process issues associated with traditional bolus capsule systems, where the capsule itself presents problems at abattoir. It is envisaged that the novel insert by comparison would be completely biodegraded with no problematic remains at abattoir.
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Beneficial Sugars in Stingless Bee Honey
Stingless bees (Meliponini) occur in all tropical and sub-tropical regions, and honey from these native bees has a long history of traditional indigenous use with a range of purported therapeutic properties. Prof Fletcher's research has identified the unusual low GI disaccharide trehalulose as a predominant sugar and distinctive marker of stingless bee honey in five species across three continents Australia, Malaysia and Brazil. The presence of this beneficial sugar has added support to the health claims of these native Meliponini honeys and provided impetus to this emerging industry. This is the first report of this unusual disaccharide as a major component of honey, and indeed the first significant natural occurrence in any food. Prof Fletcher's research team has further demonstrated that this rare sugar is produced by the bees themselves via an enzymatic isomerisation of nectar sucrose - further evidence of the unique characteristics of these stingless bees and the honey they produce.
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Natural Toxins
Prof Fletcher's research interests also encompass the identification and analysis of natural toxins and bioactives in a range of plants, fungi and agricultural products. Such toxins have the potential to form residues in agricultural products and pose a risk to both livestock and human consumers. Toxins of particular interest include mycotoxins, pyrrolizidine alkaloids, indospicine and simplexin. Her natural toxin research focusses on minimising the impacts of plant toxins on Australian livestock production. Plant toxins can have wide ranging animal impacts, depending on their chemical structure and have the potential to contribute to ill thrift through specific toxicoses such as Pimelea poisoning and pyrrolizidine alkaloid associated liver disease, and reproductive losses through abortion and teratogenic effects, or calf losses associated with premature births, weak calves, or failure to suckle. Devising strategies to deal with diverse plant toxins is not easy, as the chemical action and target organ varies considerably, and the best line of action is prevention rather than remedial treatment. In pasture systems, it is difficult to prevent consumption of poisonous plants, other than by total removal from the pasture which is generally not possible. However, plant consumption does not necessarily equal uptake of the toxin, and the approach of the proposed research is to devise strategies to enable toxin breakdown within the rumen before absorption into the animals circulatory systems. Our research approach is to capitalise on natural rumen response by isolating microbes capable of degrading toxins (for use as preventative probiotics), and investigating toxin absorbents and/or biopolymers to foster toxin-degrading microbe populations. Initially this research will be applied to the Pimelea toxin, simplexin, which causes frequently fatal poisoning in cattle grazing inland pastures of Australia with productivity losses estimated to be up to $50 million in bad years. Further interests include the presence of pyrrolizidine alkaloids in Australian honey and identification of diverse floral sources of these alkaloids using LCMS technologies to confirm alkaloid profiles. A collaborative project with Queensland Health is also investigating authenticity, adulteration and providence of these honeys using stable isotope MS techniques.
Research impacts
Throughout her career Prof Fletcher has applied her chemical skills to address diverse problems that pose threats to agricultural industries, from the identification of fruit fly pheromones to the determination of plant toxins responsible for livestock deaths, to the identification of bone volatiles attractive to phosphorous deficient cattle and more recently the identification of unusual beneficial sugars in stingless bee honey and the application of slow release devices for the release of bioactives to control enteric methane production in rangeland cattle. Her work has particular application in the areas of food safety and food security, both in Australia and overseas, including projects addressing the impacts of carcinogenic mycotoxin contamination of staple foods in sub-saharan Africa.
Current research funded by Meat and Livestock Australia (MLA) aims to develop a rumen insert that is applicable in extensive production systems to reduce methane emissions from northern Australia beef herds and applies novel biopolmyer technologies to progress the industry goal of achieving a carbon neutral beef industry by 2030. This collaborative UQ-DAF project aims to produce a rumen insert that slowly releases active-agents (such as 3-NOP) into the rumen over an extended period of time. The use of a rumen insert will mean that each animal will receive the treatment and should establish a more consistent reduced methane emission, when compared to other methods.
Works
Search Professor Mary Fletcher’s works on UQ eSpace
2023
Conference Publication
A rare health sugar, trehalulose, discovered in stingless bee honey
Zhang, Jiali, Hungerford, Natasha L., Smith, Tobias J., Yates, Hans S. A. and Fletcher, Mary T. (2023). A rare health sugar, trehalulose, discovered in stingless bee honey. 48th International Apiculture Congress, Santiago, Chile, 4-8th September 2023.
2023
Journal Article
Identification of acid hydrolysis metabolites of the Pimelea toxin simplexin for targeted UPLC-MS/MS analysis
Loh, Zhi Hung, Hungerford, Natasha L., Ouwerkerk, Diane, Klieve, Athol V. and Fletcher, Mary T. (2023). Identification of acid hydrolysis metabolites of the Pimelea toxin simplexin for targeted UPLC-MS/MS analysis. Toxins, 15 (9) 551, 551. doi: 10.3390/toxins15090551
2023
Journal Article
Organic acid profiles of Australian stingless bee honey samples determined by ion chromatography
Hungerford, Natasha L., Yates, Hans S.A., Smith, Tobias J. and Fletcher, Mary T. (2023). Organic acid profiles of Australian stingless bee honey samples determined by ion chromatography. Journal of Food Composition and Analysis, 122 105466, 1-12. doi: 10.1016/j.jfca.2023.105466
2023
Journal Article
Biodegradative controlled natural toxin release from Pimelea trichostachya-poly(3-hydroxybutyrate-co-3-hydroxyvalerate) biocomposites: towards a sustainable intra-ruminal device
Yuan, Yue, Fletcher, Mary T. and Laycock, Bronwyn (2023). Biodegradative controlled natural toxin release from Pimelea trichostachya-poly(3-hydroxybutyrate-co-3-hydroxyvalerate) biocomposites: towards a sustainable intra-ruminal device. European Polymer Journal, 195 112202, 112202. doi: 10.1016/j.eurpolymj.2023.112202
2023
Conference Publication
Macerating bees to create honey
Zhang, Jiali, Hungerford, Natasha L., Yates, Hans S.A., Smith, Tobias J. and Fletcher, Mary T. (2023). Macerating bees to create honey. Forensic and Scientific Services – Science Week 2023, Lightning talks, Coopers Plains, QLD Australia, 15-17 August 2023.
2023
Journal Article
Poisonous Plants of the Genus Pimelea: A Menace for the Australian Livestock Industry
Saleem, Rashid, Bajwa, Ali Ahsan, Campbell, Shane, Fletcher, Mary T., Kalaipandian, Sundaravelpandian and Adkins, Steve W. (2023). Poisonous Plants of the Genus Pimelea: A Menace for the Australian Livestock Industry. Toxins, 15 (6) 374, 1-17. doi: 10.3390/toxins15060374
2023
Journal Article
Factors affecting the germination ecology of Pimelea trichostachya and its relationship to field emergence
Saleem, Rashid, Campbell, Shane, Fletcher, Mary T., Kalaipandian, Sundaravelpandian and Adkins, Steve (2023). Factors affecting the germination ecology of Pimelea trichostachya and its relationship to field emergence. Plants, 12 (11) 2112, 1-15. doi: 10.3390/plants12112112
2023
Conference Publication
Opportunities for chemistry in reducing greenhouse gas emissions in agriculture
Hungerford, Natasha L. and Fletcher, Mary T. (2023). Opportunities for chemistry in reducing greenhouse gas emissions in agriculture. 1st Australian Conference on Green and Sustainable Chemistry and Engineering, Cairns, QLD, Australia, 2-5 July 2023.
2022
Other Outputs
Improving beef production through management of plant toxins (2018-2022)
Fletcher, Mary, Ouwerkerk, Diane , Hungerford, Natasha and Gilbert, Rosalind (2022). Improving beef production through management of plant toxins (2018-2022) . North Sydney, NSW, Australia: Meat and Livestock Australia.
2022
Journal Article
Unravelling biodegradation and toxin release kinetics of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)-based biocomposites in a simulated rumen environment: a preliminary study
Yuan, Yue, Gauthier, Emilie, Ouwerkerk, Diane, Fletcher, Mary T. and Laycock, Bronwyn (2022). Unravelling biodegradation and toxin release kinetics of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)-based biocomposites in a simulated rumen environment: a preliminary study. Sustainable Materials and Technologies, 33 e00498, 1-13. doi: 10.1016/j.susmat.2022.e00498
2022
Conference Publication
The origin of rare reducing sugar, trehalulose, in Australian stingless bee honey
Zhang, J., Hungerford, N. L., Smith, T. J., Yates, H. S. A. and Fletcher, M. T. (2022). The origin of rare reducing sugar, trehalulose, in Australian stingless bee honey. 34th Australian Association of Animal Sciences Conference, Cairns, QLD Australia, 5-7 July 2022.
2022
Conference Publication
In vivo rumen microbial degradation of polyhydroxyalkanoate biopolymers
Ouwerkerk, D., Gauthier, E., Yuan, Y., Costa, D. F. A., Laycock, B. and Fletcher, M.T. (2022). In vivo rumen microbial degradation of polyhydroxyalkanoate biopolymers. 34th Australian Association of Animal Sciences Conference, Cairns, QLD Australia, 5 - 7 July 2022. doi: 10.1071/ANv62n11abs
2022
Conference Publication
Effects of adsorbents and probiotics in mitigating simplexin poisoning effects in cattle fed Pimelea
Loh, Z. H., Hungerford, N. L., Ouwerkerk, D., Klieve, A. V. and Fletcher, M. T. (2022). Effects of adsorbents and probiotics in mitigating simplexin poisoning effects in cattle fed Pimelea. 34th Biennial Conference of the Australian Association of Animal Sciences, Cairns, QLD, Australia, 5 - 7 July 2022. Clayton, VIC, Australia: CSIRO Publishing.
2022
Conference Publication
Trehalulose formation in Australian stingless bees: an intermolecular isomerization of nectar sucrose
Zhang, Jiali, Hungerford, Natasha L., Yates, Hans S. A., Smith, Tobias J. and Fletcher, Mary T. (2022). Trehalulose formation in Australian stingless bees: an intermolecular isomerization of nectar sucrose. RACI National Congress, Brisbane, QLD Australia, 3-8 July 2022.
2022
Conference Publication
Sugar feeding trials establish the origin of trehalulose in stingless bee honey
Hungerford, Natasha L., Zhang, Jiali, Smith, Tobias J., Yates, Hans S. A., Chowdhury, Sadia A., Carter, James F., Carpinelli de Jesus, Matheus and Fletcher, Mary T. (2022). Sugar feeding trials establish the origin of trehalulose in stingless bee honey. RACI National Congress, Brisbane, QLD Australia, 3-8 July 2022.
2022
Conference Publication
The origin and optimization of trehalulose in Australian stingless bee honey
Zhang, J., Lai, C., Yates, H. S. A., Smith, T. J., Hungerford, N. L. and Fletcher, M. T. (2022). The origin and optimization of trehalulose in Australian stingless bee honey. 3rd Australian Native Bee Conference, Rosehill, NSW Australia, 11-12 June 2022.
2022
Conference Publication
Stingless bee honeys feature an unusual bioactive sugar, trehalulose
Hungerford, N. L., Zhang, J., Smith, T. J., Yates, H. S. A., Carpinelli de Jesus, M., Webber, D., Stone, I. S. J. , Blanchfield, J. T., Zawawi, N. and Fletcher, M. T. (2022). Stingless bee honeys feature an unusual bioactive sugar, trehalulose. 3rd Australian Native Bee Conference, Rosehill, NSW Australia, 11-12 June 2022.
2022
Journal Article
Using the natural abundance of nitrogen isotopes to identify cattle with greater efficiency in protein-limiting diets
Silva, L. F. P., Hegarty, R. S., Meale, S. J., Costa, D. A. F. and Fletcher, M. T. (2022). Using the natural abundance of nitrogen isotopes to identify cattle with greater efficiency in protein-limiting diets. Animal, 16 100551, 100551. doi: 10.1016/j.animal.2022.100551
2022
Journal Article
How is trehalulose formed by Australian stingless bees? - An intermolecular displacement of nectar sucrose
Zhang, Jiali, Hungerford, Natasha L., Yates, Hans S.A., Smith, Tobias J. and Fletcher, Mary T. (2022). How is trehalulose formed by Australian stingless bees? - An intermolecular displacement of nectar sucrose. Journal of Agricultural and Food Chemistry, 70 (21), 6530-6539. doi: 10.1021/acs.jafc.2c01732
2022
Journal Article
Unique physicochemical properties and rare reducing sugar trehalulose mandate new international regulation for stingless bee honey
Zawawi, Norhasnida, Zhang, Jiali, Hungerford, Natasha L., Yates, Hans S.A., Webber, Dennis C., Farrell, Madeleine, Tinggi, Ujang, Bhandari, Bhesh and Fletcher, Mary T. (2022). Unique physicochemical properties and rare reducing sugar trehalulose mandate new international regulation for stingless bee honey. Food Chemistry, 373 (Pt B) 131566, 131566. doi: 10.1016/j.foodchem.2021.131566
Funding
Current funding
Supervision
Availability
- Emerita Professor Mary Fletcher is:
- Not available for supervision
Supervision history
Current supervision
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Doctor Philosophy
Atypical saccharides in emerging and novel foods
Associate Advisor
Other advisors: Dr Natasha Hungerford, Dr Viviene Santiago
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Doctor Philosophy
Stingless bee enzymes for biotransformation of cane sugar to a low GI sugar
Associate Advisor
Other advisors: Professor James De Voss, Dr Loan Nguyen, Dr Natasha Hungerford
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Doctor Philosophy
Stingless bee enzymes for biotransformation of cane sugar to a low GI sugar
Associate Advisor
Other advisors: Professor James De Voss, Dr Loan Nguyen, Dr Natasha Hungerford
Completed supervision
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2024
Doctor Philosophy
Mitigation of Pimelea poisoning of livestock using adsorbents
Principal Advisor
Other advisors: Professor Bronwyn Laycock, Dr Natasha Hungerford
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2022
Doctor Philosophy
Mitigating the effects of the toxin simplexin in Pimelea poisoning of cattle by development of a microbial probiotic
Principal Advisor
Other advisors: Dr Natasha Hungerford
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2017
Doctor Philosophy
Occurrence of Mycotoxins in Harvested Maize in Kenya and Tanzania and Postharvest Control by Photosensitization
Principal Advisor
Other advisors: Professor Yasmina Sultanbawa, Dr Darren Kriticos
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2016
Doctor Philosophy
Food Safety Risk Assessment of Indospicine in Australian Camel Meat
Principal Advisor
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2023
Doctor Philosophy
Modelling the Controlled Release of Toxins within a Rumen Environment
Associate Advisor
Other advisors: Professor Bronwyn Laycock
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2022
Doctor Philosophy
Developing a new probiotic fermented milk with prebiotics for aflatoxin M1 detoxification
Associate Advisor
Other advisors: Professor Mark Turner, Professor Yasmina Sultanbawa
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2022
Doctor Philosophy
Germination triggers, persistence, and management of Pimelea trichostachya Lindl. in Queensland
Associate Advisor
Other advisors: Associate Professor Shane Campbell, Professor Steve Adkins
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2020
Doctor Philosophy
Assessing the safe use of Terminalia ferdinandiana for dietary purposes
Associate Advisor
Other advisors: Dr Michael Netzel, Professor Yasmina Sultanbawa
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2018
Doctor Philosophy
Health risk assessment of mixed contaminants: Interaction of metals on the uptake of polycyclic aromatic hydrocarbons in human liver cells
Associate Advisor
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2017
Doctor Philosophy
Factors related to differential occurrence rates of aflatoxins in maize grains: investigations with near infrared spectrometry and metabolite analysis
Associate Advisor
Other advisors: Professor Yasmina Sultanbawa
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2013
Doctor Philosophy
Studies on haemolytic compounds from fungi of sago and their role in sago haemolytic disease in Papua New Guinea
Associate Advisor
Media
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