
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
2022
Journal Article
In vitro bioaccessibility and intestinal absorption of selected bioactive compounds in Terminalia ferdinandiana
Akter, Saleha, Addepalli, Rama, Netzel, Michael, Tinggi, Ujang, Fletcher, Mary, Sultanbawa, Yasmina and Osborne, Simone (2022). In vitro bioaccessibility and intestinal absorption of selected bioactive compounds in Terminalia ferdinandiana. Frontiers in Nutrition, 8 818195, 818195. doi: 10.3389/fnut.2021.818195
2022
Conference Publication
Determination of phenolic compounds and organic acids of stingless bee honey from Malaysia and Australia
Ramlan, Nurul Ainaa Farhanah Mat, Zaini, Nur Syamimi, Hungerford, Natasha, Fletcher, Mary and Zawawi, Norhasnida (2022). Determination of phenolic compounds and organic acids of stingless bee honey from Malaysia and Australia. TropAg International Agriculture Conference 2022, Brisbane, QLD Australia, 31 October - 2 November 2022.
2021
Book
Optimising bioactive content of Australian stingless bee honey
Fletcher, Mary, Hungerford, Natasha and Smith, Tobias (2021). Optimising bioactive content of Australian stingless bee honey. Wagga Wagga, NSW Australia: AgriFutures Australia.
2021
Journal Article
Feeding sugars to stingless bees: identifying the origin of trehalulose-rich honey composition
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. (2021). Feeding sugars to stingless bees: identifying the origin of trehalulose-rich honey composition. Journal of Agricultural and Food Chemistry, 69 (35) acs.jafc.1c02859, 10292-10300. doi: 10.1021/acs.jafc.1c02859
2021
Journal Article
Impact of polyphenol-rich extracts of Terminalia ferdinandiana fruits and seeds on viability of human intestinal and liver cells in vitro
Akter, Saleha, Addepalli, Rama, Netzel, Michael, Fletcher, Mary, Sultanbawa, Yasmina and Osborne, Simone (2021). Impact of polyphenol-rich extracts of Terminalia ferdinandiana fruits and seeds on viability of human intestinal and liver cells in vitro. Food Chemistry: Molecular Sciences, 2 100024, 100024. doi: 10.1016/j.fochms.2021.100024
2021
Journal Article
Determination of ellagic acid, punicalagin, and castalagin from Terminalia ferdinandiana (Kakadu plum) by a validated UHPLC-PDA-MS/MS methodology
Akter, Saleha, Hong, Hung, Netzel, Michael, Tinggi, Ujang, Fletcher, Mary, Osborne, Simone and Sultanbawa, Yasmina (2021). Determination of ellagic acid, punicalagin, and castalagin from Terminalia ferdinandiana (Kakadu plum) by a validated UHPLC-PDA-MS/MS methodology. Food Analytical Methods, 14 (12), 2534-2544. doi: 10.1007/s12161-021-02063-8
2021
Journal Article
Extraction and determination of the Pimelea toxin simplexin in complex plant-polymer biocomposites using ultrahigh-performance liquid chromatography coupled with quadrupole Orbitrap mass spectrometry
Yuan, Yue, Hungerford, Natasha L., Gauthier, Emilie, Ouwerkerk, Diane, Yong, Ken W. L., Fletcher, Mary T. and Laycock, Bronwyn (2021). Extraction and determination of the Pimelea toxin simplexin in complex plant-polymer biocomposites using ultrahigh-performance liquid chromatography coupled with quadrupole Orbitrap mass spectrometry. Analytical and Bioanalytical Chemistry, 413 (20), 5121-5133. doi: 10.1007/s00216-021-03475-5
2021
Conference Publication
Stingless bees produce honey rich in the beneficial disaccharide, trehalulose
Hungerford, Natasha L., Zhang, Jiali, Smith, Tobias J., Carpinelli de Jesus, Matheus, Yates, Hans S. A., Chowdhury, Sadia A., Carter, James F., Webber, Dennis, Stone, Isobella S. J., Blanchfield, Joanne T., Zawawi, Norhasnida, Schirra, Horst J., Tran, Trong D. and Fletcher, Mary T. (2021). Stingless bees produce honey rich in the beneficial disaccharide, trehalulose. Symposium of Research & Innovation for Food (SoRIF), Universiti Teknologi MARA, Malaysia via WebEX, 23-24 June 2021.
2021
Journal Article
Occurrence of environmental contaminants (pesticides, herbicides, PAHs) in Australian/Queensland Apis mellifera honey
Hungerford, Natasha L., Fletcher, Mary T., Tsai, Heng Hang, Hnatko, Darina, Swann, Lorinda J., Kelly, Cassandra L., Anuj, Shalona R., Tinggi, Ujang, Webber, Dennis C., Were, Stephen T. and Tan, Benjamin L. L. (2021). Occurrence of environmental contaminants (pesticides, herbicides, PAHs) in Australian/Queensland Apis mellifera honey. Food Additives and Contaminants: Part B, 14 (3), 1-13. doi: 10.1080/19393210.2021.1914743
2021
Journal Article
Degradation of the indospicine toxin from Indigofera spicata by a mixed population of rumen bacteria
Gilbert, Rosalind A., Netzel, Gabriele, Chandra, Kerri, Ouwerkerk, Diane and Fletcher, Mary T. (2021). Degradation of the indospicine toxin from Indigofera spicata by a mixed population of rumen bacteria. Toxins, 13 (6) 389, 389. doi: 10.3390/toxins13060389
2021
Journal Article
The inactivation by curcumin-mediated photosensitization of Botrytis cinerea apores isolated from strawberry fruits
Huang, Li, Yong, Ken W. L., Fernando, W. Chrishanthi, Carpinelli de Jesus, Matheus, De Voss, James J., Sultanbawa, Yasmina and Fletcher, Mary T. (2021). The inactivation by curcumin-mediated photosensitization of Botrytis cinerea apores isolated from strawberry fruits. Toxins, 13 (3) 196, 196. doi: 10.3390/toxins13030196
2021
Journal Article
The influence of weather on the occurrence of aflatoxin B1 in harvested maize from Kenya and Tanzani.
Temba, Benigni A., Darnell, Rose E., Gichangi, Anne, Lwezaura, Deogratias, Pardey, Philip G., Harvey, Jagger J., Karanja, James, Massomo, Said M. S., Ota, Noboru, Wainaina, James M., Fletcher, Mary T. and Kriticos, Darren J. (2021). The influence of weather on the occurrence of aflatoxin B1 in harvested maize from Kenya and Tanzani.. Foods, 10 (2) 216, 216. doi: 10.3390/foods10020216
2021
Journal Article
The validity of protein in Australian honey as an internal standard for C4 sugar adulteration
Chowdhury, Sadia A., Carter, James. F., Anuj, Shalona R., Cozzolino, Daniel, Hungerford, Natasha L. and Fletcher, Mary T. (2021). The validity of protein in Australian honey as an internal standard for C4 sugar adulteration. Food Analytical Methods, 14 (4), 823-833. doi: 10.1007/s12161-020-01938-6
2021
Conference Publication
Stingless Bee Honey’s unique properties
Hungerford, Natasha L., Zhang, Jiali, Smith, Tobias J., Carpinelli de Jesus, Matheus, Yates, Hans S. A., Chowdhury, Sadia A., Carter, James F., Webber, Dennis, Stone, Isobella S. J., Blanchfield, Joanne T., Zawawi, Norhasnida and Fletcher, Mary T. (2021). Stingless Bee Honey’s unique properties. Australian Apitherapy Association Global Conference 2021, Online, 26-27 November 2021.
2021
Conference Publication
Combating Pimelea poisoning with biodegradable biocomposite-based boluses: an investigation into the slow release of toxins in the rumen environment
Yuan, Y., Gauthier, E., Hungerford, N. L., Ouwerkerk, D., Laycock, B. and Fletcher, M. T. (2021). Combating Pimelea poisoning with biodegradable biocomposite-based boluses: an investigation into the slow release of toxins in the rumen environment. Australian Association of Animal Sciences Biennial Conference (AAAS 2021), Fremantle, WA Australia, 1-3 February 2021. Australian Association of Animal Sciences and CSIRO. doi: 10.1071/ANv61n3abs
2021
Conference Publication
Enriching for rumen bacteria to degrade the Pimelea plant toxin simplexin, in an anaerobic in vitro fermenter
Ouwerkerk, D., Gilbert, R. A., Gravel, J. L., Maguire, A. J., Minchin, C. M., Hungerford, N. L., Loh, Z. H. and Fletcher, M. T. (2021). Enriching for rumen bacteria to degrade the Pimelea plant toxin simplexin, in an anaerobic in vitro fermenter. Australian Association of Animal Sciences Biennial Conference (AAAS 2021), Fremantle, WA Australia, 1-3 February 2021. Australian Association of Animal Sciences and CSIRO. doi: 10.1071/ANv61n3abs
2021
Journal Article
Study gets the buzz on stingless bee honey
Hungerford, Natasha L., Fletcher, Mary T. and Zawawi, Norhasnida (2021). Study gets the buzz on stingless bee honey. TheScienceBreaker, 7 (1). doi: 10.25250/thescbr.brk453
2021
Conference Publication
Pimelea toxin simplexin and its potential degradation products
Loh, Z. H., Hungerford, N. L., Ouwerkerk, D., Klieve, A. V. and Fletcher, M. T. (2021). Pimelea toxin simplexin and its potential degradation products. Australian Association of Animal Sciences Biennial Conference (AAAS 2021), Fremantle, WA Australia, 1-3 February 2021. Australian Association of Animal Sciences and CSIRO. doi: 10.1071/ANv61n3abs
2021
Conference Publication
Analysis of the Pimelea toxin simplexin for the development of a cattle microbial probiotic
Loh, Zhi Hung, Hungerford, Natasha L., Ouwerkerk, Diane, Klieve, Athol V. and Fletcher, Mary T. (2021). Analysis of the Pimelea toxin simplexin for the development of a cattle microbial probiotic. 1st International Electronic Conference on Toxins, Online, 13-31 January 2021. Basel, Switzerland: Sciforum. doi: 10.3390/IECT2021-09149
2020
Journal Article
Interactions between phytochemicals and minerals in Terminalia ferdinandiana and implications for mineral bioavailability
Akter, Saleha, Netzel, Michael, Tinggi, Ujang, Fletcher, Mary, Osborne, Simone and Sultanbawa, Yasmina (2020). Interactions between phytochemicals and minerals in Terminalia ferdinandiana and implications for mineral bioavailability. Frontiers in Nutrition, 7 598219, 598219. doi: 10.3389/fnut.2020.598219
Funding
Current funding
Supervision
Availability
- Emerita Professor Mary Fletcher is:
- Not available for supervision
Supervision history
Current supervision
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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
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Doctor Philosophy
Atypical saccharides in emerging and novel foods
Associate Advisor
Other advisors: Dr Natasha Hungerford, Dr Viviene Santiago
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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