
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
-
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.
-
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.
-
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
2019
Journal Article
Analysis of Pyrrolizidine alkaloids in Queensland honey: Using low temperature chromatography to resolve stereoisomers and identify botanical sources by UHPLC-MS/MS
Hungerford, Natasha L., Carter, Steve J., Anuj, Shalona R., Tan, Benjamin L. L., Hnatko, Darina, Martin, Christopher L., Sharma, Elipsha, Yin, Mukan, Nguyen, Thao T. P., Melksham, Kevin J. and Fletcher, Mary T. (2019). Analysis of Pyrrolizidine alkaloids in Queensland honey: Using low temperature chromatography to resolve stereoisomers and identify botanical sources by UHPLC-MS/MS. Toxins, 11 (12) 726, 726. doi: 10.3390/toxins11120726
2019
Journal Article
Curcumin-based photosensitization inactivates Aspergillus flavus and reduces aflatoxin B1 in maize kernels
Temba, Benigni A., Fletcher, Mary T., Fox, Glen P., Harvey, Jagger, Okoth, Sheila A. and Sultanbawa, Yasmina (2019). Curcumin-based photosensitization inactivates Aspergillus flavus and reduces aflatoxin B1 in maize kernels. Food Microbiology, 82, 82-88. doi: 10.1016/j.fm.2018.12.013
2019
Journal Article
Antioxidant rich extracts of Terminalia ferdinandiana inhibit the growth of foodborne bacteria
Akter, Saleha, Netzel, Michael E., Tinggi, Ujang, Osborne, Simone A., Fletcher, Mary T. and Sultanbawa, Yasmina (2019). Antioxidant rich extracts of Terminalia ferdinandiana inhibit the growth of foodborne bacteria. Foods, 8 (8) 281, 281. doi: 10.3390/foods8080281
2019
Journal Article
Antioxidant-rich extracts of Terminalia ferdinandiana interfere with estimation of cell viability
Akter, Saleha, Addepalli, Rama, Netzel, Michael E., Tinggi, Ujang, Fletcher, Mary T., Sultanbawa, Yasmina and Osborne, Simone A. (2019). Antioxidant-rich extracts of Terminalia ferdinandiana interfere with estimation of cell viability. Antioxidants, 8 (6) 191, 191. doi: 10.3390/antiox8060191
2019
Journal Article
Pyrrolizidine alkaloids of Blue Heliotrope (Heliotropium amplexicaule) and their presence in Australian honey
Carpinelli de Jesus, Matheus, Hungerford, Natasha L., Carter, Steve J., Anuj, Shalona R., Blanchfield, Joanne T., De Voss, James Joseph and Fletcher, Mary T. (2019). Pyrrolizidine alkaloids of Blue Heliotrope (Heliotropium amplexicaule) and their presence in Australian honey. Journal of Agricultural and Food Chemistry, 67 (28) acs.jafc.9b02136, 7995-8006. doi: 10.1021/acs.jafc.9b02136
2019
Journal Article
Bioaccumulation and Distribution of Indospicine and Its Foregut Metabolites in Camels Fed Indigofera spicata
Netzel, Gabriele, Tan, Eddie T. T., Yin, Mukan, Giles, Cindy, Yong, Ken W. L., Al Jassim, Rafat and Fletcher, Mary T. (2019). Bioaccumulation and Distribution of Indospicine and Its Foregut Metabolites in Camels Fed Indigofera spicata. Toxins, 11 (3) 169, 169. doi: 10.3390/toxins11030169
2019
Journal Article
Assessing the risk of residues of the toxin indospicine in bovine muscle and liver from north-west Australia
Netzel, Gabriele, Palmer, Dieter G., Masters, Anne M., Tai, Samantha Y., Allen, Jeremy G. and Fletcher, Mary T. (2019). Assessing the risk of residues of the toxin indospicine in bovine muscle and liver from north-west Australia. Toxicon, 163, 48-58. doi: 10.1016/j.toxicon.2019.03.007
2019
Conference Publication
Adsorbents for the sequestration of the Pimelea toxin, simplexin
Gordon, Russell J., Hungerford, Natasha L., Laycock, Bronwyn, Ouwerkerk, Diane and Fletcher, Mary T. (2019). Adsorbents for the sequestration of the Pimelea toxin, simplexin. Northern Beef Research Update Conference (NBRUC) 2019, Brisbane, QLD, Australia, 19 - 22 August 2019.
2019
Conference Publication
Biopolymer composites for slow release to manage Pimelea poisoning in cattle
Gauthier, Emilie, Ouwerkerk, Diane, Laycock, Bronwyn and Fletcher, Mary (2019). Biopolymer composites for slow release to manage Pimelea poisoning in cattle. The Third International Tropical Agriculture Conference TropAg 2019 , Brisbane, QLD Australia, 11-13 November 2019. Basel, Switzerland: MDPI. doi: 10.3390/proceedings2019036097
2019
Conference Publication
Mitigating the effects of the toxin simplexin in pimelea poisoning of cattle by development of a microbial probiotic
Loh, Z. H., Hungerford, N. L., Ouwerkerk, D., Klieve, A. V. and Fletcher, M. T. (2019). Mitigating the effects of the toxin simplexin in pimelea poisoning of cattle by development of a microbial probiotic. 4th Queensland Annual Chemistry Symposium QACS 2019, Brisbane, QLD, Australia, 29 November 2019.
2019
Conference Publication
The Pimelea story – application of novel approaches to control toxicity in cattle
Fletcher, Mary and Ouwerkerk, Diane (2019). The Pimelea story – application of novel approaches to control toxicity in cattle. Australian Veterinary Association Queensland Division,, Gold Coast, Queensland, 22-24 March 2019.
2019
Conference Publication
Modelling the controlled release of toxins in a rumen environment
Yuan, Yue, Gauthier, Emilie, Hungerford, Natasha L., Ouwerkerk, Diane, Fletcher, Mary T. and Laycock, Bronwyn (2019). Modelling the controlled release of toxins in a rumen environment. 4th Queensland Annual Chemistry Symposium QACS 2019, Brisbane, QLD, Australia, 29 November 2019.
2019
Conference Publication
In vitro bioaccessibility and transport of ascorbic and ellagic acid in Terminalia ferdinandiana (Kakadu plum) extracts
Akter, Saleha, Addepalli, Rama, Netzel, Michael E., Tinggi, Ujang, Fletcher, Mary T., Sultanbawa, Yasmina and Osborne, Simone A. (2019). In vitro bioaccessibility and transport of ascorbic and ellagic acid in Terminalia ferdinandiana (Kakadu plum) extracts. Active Integrated Matter (AIM) Conference 2019, Melbourne, VIC, Australia, 14-16 May 2019.
2019
Conference Publication
Antimicrobial activity and ellagitannins from Terminalia ferdinandiana
Akter, Saleha, Hong, Hung Trieu, Netzel, Michael E., Tinggi, Ujang, Osborne, Simone, Fletcher, Mary and Sultanbawa, Yasmina (2019). Antimicrobial activity and ellagitannins from Terminalia ferdinandiana. TropAg2019, International Tropical Agriculture Conference, Brisbane, QLD, Australia, 11-13 November 2019. Basel, Switzerland: MDPI. doi: 10.3390/proceedings2019036081
2019
Conference Publication
Mitigating the effects of the toxin simplexin in pimelea poisoning of cattle by development of a microbial probiotic
Loh, Zhi Hung, Hungerford, Natasha L., Ouwerkerk, Diane, Gilbert, Rosalind A., Gravel, Jennifer, Minchin, Catherine M., Maguire, Anita J., Yong, Ken, Klieve, Athol and Fletcher, Mary (2019). Mitigating the effects of the toxin simplexin in pimelea poisoning of cattle by development of a microbial probiotic. TropAg2019, International Tropical Agriculture Conference, Brisbane, QLD, Australia, 11 - 13 November 2019.
2019
Conference Publication
Are toxic Pimelea secondary compounds absorbed via the intestinal lymph?
Gordon, Russell J., Hungerford, Natasha L., Laycock, Bronwyn and Fletcher, Mary T. (2019). Are toxic Pimelea secondary compounds absorbed via the intestinal lymph?. 4th Queensland Annual Chemistry Symposium QACS 2019, Brisbane, QLD, Australia, 29 November 2019.
2018
Journal Article
NIRS calibration of aflatoxin in maize
Darnell, Ross E., Harvey, Jagger J., Fox, Glen P., Fletcher, Mary T., Wainaina, James, Wanjuki, Immaculate and Turner, Warwick J. (2018). NIRS calibration of aflatoxin in maize. Australian Journal of Chemistry, 71 (11), 868-873. doi: 10.1071/CH18316
2018
Journal Article
Release of indospicine from contaminated camel meat following cooking and simulated gastrointestinal digestion: implications for human consumption
Sultan, Saira, Giles, Cindy, Netzel, Gabriele, Osborne, Simone A., Netzel, Michael E. and Fletcher, Mary T. (2018). Release of indospicine from contaminated camel meat following cooking and simulated gastrointestinal digestion: implications for human consumption. Toxins, 10 (9) 356, 356. doi: 10.3390/toxins10090356
2018
Journal Article
Learned behaviours lead to bone ingestion by phosphorus-deficient cattle
Dixon, R. M., Fletcher, M. T., Goodwin, K. L., Reid, D. J., Yong, K.W.L., McNeill, D. M. and Petherick, J. C. (2018). Learned behaviours lead to bone ingestion by phosphorus-deficient cattle. Animal Production Science, 59 (5), 921-932. doi: 10.1071/AN17251
2018
Journal Article
Metabolites Identified during Varied Doses of Species in Grains, and Their Correlation with Aflatoxin Levels
Falade, Titilayo D. O., Chrysanthopoulos, Panagiotis K., Hodson, Mark P., Sultanbawa, Yasmina, Fletcher, Mary, Darnell, Ross, Korie, Sam and Fox, Glen (2018). Metabolites Identified during Varied Doses of Species in Grains, and Their Correlation with Aflatoxin Levels. Toxins, 10 (5) 187, 187. doi: 10.3390/toxins10050187
Funding
Current funding
Supervision
Availability
- Emerita Professor Mary Fletcher is:
- Not available for supervision
Supervision history
Current supervision
-
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
-
Doctor Philosophy
Atypical saccharides in emerging and novel foods
Associate Advisor
Other advisors: Dr Natasha Hungerford, Dr Viviene Santiago
-
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
-
2024
Doctor Philosophy
Mitigation of Pimelea poisoning of livestock using adsorbents
Principal Advisor
Other advisors: Professor Bronwyn Laycock, Dr Natasha Hungerford
-
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
-
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
-
2016
Doctor Philosophy
Food Safety Risk Assessment of Indospicine in Australian Camel Meat
Principal Advisor
-
2023
Doctor Philosophy
Modelling the Controlled Release of Toxins within a Rumen Environment
Associate Advisor
Other advisors: Professor Bronwyn Laycock
-
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
-
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
-
2020
Doctor Philosophy
Assessing the safe use of Terminalia ferdinandiana for dietary purposes
Associate Advisor
Other advisors: Dr Michael Netzel, Professor Yasmina Sultanbawa
-
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
-
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
-
-
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
Enquiries
For media enquiries about Emerita Professor Mary Fletcher's areas of expertise, story ideas and help finding experts, contact our Media team: