
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
2012
Edited Outputs
Technology for Food Quality
Glenn Graham, Michael Netzel, Trudy Graham, Mary Fletcher, Gloria Karagianis, Cindy Giles, Ujang Tinggi and Pieter Scheelings eds. (2012). Technology for Food Quality. 12th Government Food Analysts Conference, Brisbane, Australia, 22-24 February 2011. Health and Food Sciences Precinct (HFSP).
2012
Conference Publication
Indigofera spicata (creeping indigo) poisoning of horses in Australia
Ossedryver, S. M. and Fletcher, M. T. (2012). Indigofera spicata (creeping indigo) poisoning of horses in Australia. 7th Conference of The World Mycotoxin Forum and XIIIth IUPAC International Symposium on Mycotoxins and Phycotoxins (WMFmeetsIUPAC2012), Rotterdam, Netherlands, 5-9 November 2012.
2012
Conference Publication
Ptaquiloside survey of milk samples from Atherton Tableland
Fletcher, Mary T., Gummow, Bruce, Brock, Ian J, Tranter, William P. and Gardiner, Christopher P. (2012). Ptaquiloside survey of milk samples from Atherton Tableland. 12th Government Food Analysts Conference, Brisbane, Australia, 22-24 February 2011. Coopers Plains, QLD, Australia: Health and Food Sciences Precinct (HFSP).
2011
Journal Article
Crotalaria medicaginea associated with horse deaths in Northern Australia: New pyrrolizidine alkaloids
Fletcher, Mary T., Hayes, Patricia Y., Somerville, Michael J. and De Voss, James J. (2011). Crotalaria medicaginea associated with horse deaths in Northern Australia: New pyrrolizidine alkaloids. Journal of Agricultural and Food Chemistry, 59 (21), 11888-11892. doi: 10.1021/jf203147x
2011
Journal Article
Residue potential of norsesquiterpene glycosides in tissues of cattle fed austral bracken (Pteridium esculentum)
Fletcher, Mary T., Reichmann, Keith G., Brock, Ian J., McKenzie, Ross A. and Blaney, Barry J. (2011). Residue potential of norsesquiterpene glycosides in tissues of cattle fed austral bracken (Pteridium esculentum). Journal of Agricultural and Food Chemistry, 59 (15), 8518-8523. doi: 10.1021/jf201342t
2011
Journal Article
Norsesquiterpene glycosides in bracken ferns (Pteridium esculentum and Pteridium aquilinum subsp. wightianum) from eastern Australia: reassessed poisoning risk to animals
Fletcher, Mary T., Brock, Ian J., Reichmann, Keith G., McKenzie, Ross A. and Blaney, Barry J. (2011). Norsesquiterpene glycosides in bracken ferns (Pteridium esculentum and Pteridium aquilinum subsp. wightianum) from eastern Australia: reassessed poisoning risk to animals. Journal of Agricultural and Food Chemistry, 59 (9), 5133-5138. doi: 10.1021/jf104267c
2011
Journal Article
Hepatotoxicosis in dogs consuming a diet of camel meat contaminated with indospicine
Fitzgerald, L. M., Paul, A., Fletcher, M. T., Mansfield, C. S. and O'Hara, A. J. (2011). Hepatotoxicosis in dogs consuming a diet of camel meat contaminated with indospicine. Australian Veterinary Journal, 89 (3), 95-100. doi: 10.1111/j.1751-0813.2010.00684.x
2011
Conference Publication
Indospicine - a natural residue that kills dogs
Fletcher, Mary T., Ossedryver, Selina M. and Reichmann, Keith G. (2011). Indospicine - a natural residue that kills dogs. 23rd Conference of Residue Chemists, Brisbane, 25 - 28 October 2011.
2011
Conference Publication
Sago haemolytic disease: A foodborne toxicosis with complex aetiology in Papua New Guinea
Greenhil, Andrew, Pue, Aisak, Shipton, Warren, Blaney, Barry, Fletcher, Mary, Ng, Jack and Warner, Jeff (2011). Sago haemolytic disease: A foodborne toxicosis with complex aetiology in Papua New Guinea. ASM 2011 Australian Society for Microbiology (ASM) Annual Scientific Meeting, Hobart, Australia, 4-8 July 2011.
2011
Book Chapter
Risks from plants containing pyrrolizidine alkaloids for livestock and meat quality in Northern Australia
Fletcher, M. T., McKenzie, R. A., Reichmann, K. G. and Blaney, B. J. (2011). Risks from plants containing pyrrolizidine alkaloids for livestock and meat quality in Northern Australia. Poisoning by plants, mycotoxins, and related toxins. (pp. 208-218) edited by Franklin Riet-Correa, Jim Pfister, Ana Lucia Schild and Terrie Wierenga. Wallingford, England, U.K.: CAB International.
2011
Conference Publication
Ptaquiloside milk residues: Do they pose a public health risk in Northern QLD?
Gummow, B., Tranter, W. P., Fletcher, M. T., Brock, I. J. and Gariner, C. P. (2011). Ptaquiloside milk residues: Do they pose a public health risk in Northern QLD?. Australian College of Veterinary Scientists Science Week, Gold Coast, Australia, 30 June - 2 July 2011.
2011
Book Chapter
LC/MS/MS analysis of the daphnane orthoester simplexin in poisonous Pimelea species of Australian rangelands
Fletcher, M. T., Chow, K. Y. S., Silcock, R. G. and Milson, J. A. (2011). LC/MS/MS analysis of the daphnane orthoester simplexin in poisonous Pimelea species of Australian rangelands. Poisoning by plants, mycotoxins, and related toxins. (pp. 550-556) edited by Franklin Riet-Correa, Jim Pfister, Ana Lucia Schild and Terrie Wierenga. Wallingford, England, U.K.: CAB International.
2011
Book Chapter
Risks from plants containing pyrrolizidine alkaloids for livestock and meat quality in northern Australia
Fletcher, M. T., McKenzie, R. A., Reichmann, K. G. and Blaney, B. J. (2011). Risks from plants containing pyrrolizidine alkaloids for livestock and meat quality in northern Australia. Poisoning by Plants, Mycotoxins, and Related Toxins. (pp. 208-214) OXON, ENGLAND: CABI Publishing.
2010
Journal Article
Daphnane- and tigliane-type diterpenoid esters and orthoesters from Pimelea elongata
Hayes, PY, Chow, S, Somerville, MJ, Fletcher, MT and De Voss, JJ (2010). Daphnane- and tigliane-type diterpenoid esters and orthoesters from Pimelea elongata. Journal of Natural Products, 73 (11), 1907-1913. doi: 10.1021/np1005746
2010
Journal Article
Analysis of Daphnane Orthoesters in Poisonous Australian Pimelea Species by Liquid Chromatography (vol 58, pg 7482, 2010)
Chow, Sharon, Fletcher, Mary T. and Mckenzie, Ross A. (2010). Analysis of Daphnane Orthoesters in Poisonous Australian Pimelea Species by Liquid Chromatography (vol 58, pg 7482, 2010). Journal of Agricultural and Food Chemistry, 58 (14), 8470-8470. doi: 10.1021/jf1025778
2010
Journal Article
Analysis of daphnane orthoesters in poisonous australian pimelea species by liquid chromatography-tandem mass spectrometry
Chow, Sharon, Fletcher, Mary T. and Mckenzie, Ross A. (2010). Analysis of daphnane orthoesters in poisonous australian pimelea species by liquid chromatography-tandem mass spectrometry. Journal of Agricultural and Food Chemistry, 58 (12), 7482-7487. doi: 10.1021/jf101752r
2010
Journal Article
Ptesculentoside, a novel norsesquiterpene glucoside from the Australian bracken fern Pteridium esculentum
Fletcher, Mary T., Hayes, Patricia Y., Somerville, Michael, J. and De Voss, James J. (2010). Ptesculentoside, a novel norsesquiterpene glucoside from the Australian bracken fern Pteridium esculentum. Tetrahedron Letters, 51 (15), 1997-1999. doi: 10.1016/j.tetlet.2010.02.032
2010
Journal Article
Haemolytic fungi isolated from sago starch in Papua New Guinea
Greenhill, A. R., Blaney, B. J., Shipton, W. A., Pue, A., Fletcher, M. T. and Warner, J. M. (2010). Haemolytic fungi isolated from sago starch in Papua New Guinea. MYCOPATHOLOGIA, 169 (2), 107-115. doi: 10.1007/s11046-009-9235-3
2010
Conference Publication
Hepatotoxicosis in dogs following consumption of indospicine contaminated camel meat
Fitzgerald, Louise, Fletcher, Mary, Paul, Amanda, Mansfield, Caroline and O'Hara, Amanda (2010). Hepatotoxicosis in dogs following consumption of indospicine contaminated camel meat. Annual Conference of the Australian Society for Veterinary Pathology, Freemantle, Western Australia, September 3 - 5 2010. Australia: Australian Society of Veterinary Pathology.
2010
Journal Article
Spiroacetal biosynthesis in fruit flies is complex: distinguishable origins of the same major spiroacetal released by different Bactrocera spp.
Schwartz, Brett D., Booth, Yvonne K., Fletcher, Mary T., Kitching, William and De Voss, James J. (2010). Spiroacetal biosynthesis in fruit flies is complex: distinguishable origins of the same major spiroacetal released by different Bactrocera spp.. Chemical Communications, 46 (9), 1526-1528. doi: 10.1039/b917977a
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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