
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
2016
Conference Publication
Aflatoxin contamination predictions in single kernels of maize
Falade, T. D. O, Harvey, J., Fletcher, M., Sultanbawa, Y. and Fox, G. (2016). Aflatoxin contamination predictions in single kernels of maize. The 17th ANISG/NZNIRSS Conference - 'Steaming on with NIR', Moama NSW Australia, 19-21 April 2016.
2016
Conference Publication
A Possible Way Forward with Pimelea Poisoning in Australian Rangelands
Silcock, Richard, Fletcher, Mary T. and Ouwerkerk, Diane (2016). A Possible Way Forward with Pimelea Poisoning in Australian Rangelands. 10th International Rangeland Congress, Saskatoon, Saskatchewan, Canada, 16-22 July 2016. Saskatoon, Saskatchewan, Canada: 10th International Rangeland Congress.
2016
Conference Publication
CTX-1 as a diagnostic marker of bone mobilisation in Bos indicus cows
Anderson, S. T., Benvenutti, M., Spiers, J. G., Goodwin, K. L., Kidd, L., Fletcher, M. T. and Dixon, R. M. (2016). CTX-1 as a diagnostic marker of bone mobilisation in Bos indicus cows. Northern Australia Beef Research Update Conference, Rockhampton, QLD Australia, 15 - 18 August 2016. Gympie, QLD Australia: Queensland North Australia Beef Research Council.
2016
Conference Publication
Effects of diet P during late pregnancy and early lactation on performance of mature Droughtmaster cows
Dixon, R., Benvenutti, M., Goodwin, K., Kidd, L., Anderson, S., Mayer, R. and Fletcher, M. (2016). Effects of diet P during late pregnancy and early lactation on performance of mature Droughtmaster cows. Northern Australia Beef Research Update Conference, Rockhampton, QLD Australia, 15 - 18 August 2016. Gympie, QLD Australia: Queensland North Australia Beef Research Council.
2016
Conference Publication
Blood sampling for P screen - tail versus jugular
Fletcher, M. T., Goodwin, K. L., Benvenutti, M., Reid, D. J., Anderson, S. T., Kidd, L. and Dixon, R. M. (2016). Blood sampling for P screen - tail versus jugular. Northern Australia Beef Research Update Conference, Rockhampton, QLD Australia, 15 - 18 August 2016. Gympie, QLD Australia: Queensland North Australia Beef Research Council.
2016
Conference Publication
In vitro digestion of indospicine-contaminated camel meat cooked by microwave
Sultan, S., Giles, C., Netzel, G., Osborne, S., Netzel, M. and Fletcher, M. (2016). In vitro digestion of indospicine-contaminated camel meat cooked by microwave. 1st Food Chemistry Conference, Shaping the Future of Food Quality, Health and Safety, Amsterdam, The Netherlands, 30 October – 1 November 2016.
2016
Conference Publication
Post-weaning phosphorus supplementation restores bone volume in pregnant cors independently of metabolisable energy
Kidd, L., McNeill, D. M., Castells, L., Goodwin, K. L., Fletcher, M. T., Anderson, S. T. and Dixon, R. M. (2016). Post-weaning phosphorus supplementation restores bone volume in pregnant cors independently of metabolisable energy. Northern Australia Beef Research Update Conference, Rockhampton, QLD Australia, 21 - 23 August 2016. Gympie, QLD Australia: Queensland North Australia Beef Research Council.
2016
Journal Article
Inactivation of Aspergillus flavus spores by curcumin-mediated photosensitization
Temba, Benigni A., Fletcher, Mary T., Fox, Glen P., Harvey, Jagger J. W. and Sultanbawa, Yasmina (2016). Inactivation of Aspergillus flavus spores by curcumin-mediated photosensitization. Food Control, 59, 708-713. doi: 10.1016/j.foodcont.2015.06.045
2016
Journal Article
Synthesis of L-Indospicine, [5,5,6-2H3 ]- L-Indospicine and L-Norindospicine
Lang, Cheng-Shan, Wong, Siew-Hoon, Chow, Sharon, Challinor, Victoria L., Yong, Ken W. L., Fletcher, Mary T., Arthur, Dionne M., Ng, Jack C. and De Voss, James J. (2016). Synthesis of L-Indospicine, [5,5,6-2H3 ]- L-Indospicine and L-Norindospicine. Organic and Biomolecular Chemistry, 14 (28), 6826-6832. doi: 10.1039/C6OB01187J
2016
Conference Publication
Indospicine toxicity in human intestinal cell lines
Sultan, S., Netzel, G., Osborne, S., Addepalli, R., Chen, W., Netzel, M. and Fletcher, M. (2016). Indospicine toxicity in human intestinal cell lines. 1st Food Chemistry Conference, Shaping the Future of Food Quality, Health and Safety, Amsterdam, The Netherlands, 30 October – 1 November 2016.
2016
Conference Publication
Effects of diet phosphorus and energy intake during late pregnancy on performance of Droughtmaster heifers
Benvenutti, M., Dixon, R., Goodwin, K., Anderson, S., Kidd, L., Mayer, R. and Fletcher, M. (2016). Effects of diet phosphorus and energy intake during late pregnancy on performance of Droughtmaster heifers. Northern Australia Beef Research Update Conference, Rockhampton, QLD Australia, 15 - 18 August 2016. Gympie, QLD Australia: Queensland North Australia Beef Research Council.
2016
Conference Publication
The use of serial bone biopsies to investigate phosphorus deficiency in growing, pregnant and lactating cattle
Kidd, L. J., Dixon, R. M., Quigley, S. P., McNeill, D. M., Poppi, D. P., Castells, L., Fletcher, M. T., Goodwin, K. L. and Anderson, S. T. (2016). The use of serial bone biopsies to investigate phosphorus deficiency in growing, pregnant and lactating cattle. Australian and New Zealand Bone and Mineral Society, Gold Coast, QLD Australia, 24-28 August 2016.
2015
Journal Article
Photodynamic inactivation of Aspergillus flavus mediated by Bidens pilosa extract
Temba, B. A., Fletcher, M. T., Fox, G. P., Harvey, J. W. and Sultanbawa, Y. (2015). Photodynamic inactivation of Aspergillus flavus mediated by Bidens pilosa extract. Tanzania Veterinary Journal, 30 (1), 42-50.
2015
Journal Article
The occurence and toxicity of indospicine to grazing animals
Fletcher, Mary T., Al Jassim, Rafat A.M and Cawdell-Smith, A. Judith (2015). The occurence and toxicity of indospicine to grazing animals. Agriculture, 5 (3), 427-440. doi: 10.3390/agriculture5030427
2015
Conference Publication
Determination of polycyclic aromatic hydrocarbons in spiked and aged soil using modified QuEChERS and gas chromatography with mass spectrometry
Lal, Vincent, Peng, Cheng, Fletcher, Mary T., Were, Stephen T. and Ng, Jack C. (2015). Determination of polycyclic aromatic hydrocarbons in spiked and aged soil using modified QuEChERS and gas chromatography with mass spectrometry. International Contaminated Site Remediation Conference, Melbourne, VIC, Australia, 13-16 September 2015. Newcastle, NSW, Australia: CRC Care.
2015
Conference Publication
Responses of Bos indicus cows in early lactation to dietary phosphorus deficiency
Benvenutti, M., Dixon, R. M., Goodwin, K. L., Kidd, L., Mayer, R., Fletcher, M. T. and Anderson, S. (2015). Responses of Bos indicus cows in early lactation to dietary phosphorus deficiency. Recent Advances in Animal Nutrition in Australia, Armidale, NSW, Australia, 26-28 October 2015. Armidale, NSW, Australia: School of Environmental and Rural Science, University of New England.
2015
Book Chapter
Effect of the Pimelea Toxin Simplexin on Cattle
Fletcher, Mary T., Ossedryver, Selina M. and Chow, Sharon (2015). Effect of the Pimelea Toxin Simplexin on Cattle. Poisonous Plants: Toxicology, Ecology, Management, and Medicine. (pp. 83-88) edited by Mengli Zhao, Terrie Wierenga and Kip Panter. Hohhot, Inner Mongolia, Chin: ISOPP9.
2015
Conference Publication
Capacity of young cows to gain bone and improve lactation
Castells, L., Dixon, R. M., Kidd, L., Goodwin, K. L., Mayer, R., Fletcher, M. T. and McNeill, D. M. (2015). Capacity of young cows to gain bone and improve lactation. Recent Advances in Animal Nutrition in Australia, Armidale, NSW, Australia, 26-28 October 2015. Armidale, NSW, Australia: School of Environmental and Rural Science, University of New England.
2015
Conference Publication
In vitro digestion models for measuring Indospicine bioaccessibility and stability in Camel meat.
Sultan S, Netzel G, Osborne S, Netzel M and Fletcher M (2015). In vitro digestion models for measuring Indospicine bioaccessibility and stability in Camel meat.. Tropical Agriculture Conference, Brisbane Australia, 16-18 November 2015.
2015
Book Chapter
Suspected toxic hepatopathy of plant origin in wild southern hairy nosed wombat (Lasiorhinus latifrons)
Woolford, Lucy, Fletcher, Mary and Boardman, Wayne (2015). Suspected toxic hepatopathy of plant origin in wild southern hairy nosed wombat (Lasiorhinus latifrons). Poisonous Plants: Toxicology, Ecology, Management, and Medicine. (pp. 100-106) edited by Mengli Zhao, Terrie Wierenga and Kip Panter. Hohhot, Inner Mongolia, China: ISOPP9.
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
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
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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