Professor Mary Fletcher

Professorial Research Fellow

Centre for Animal Science
Queensland Alliance for Agriculture and Food Innovation

Affiliate Associate Professor

School of Chemistry and Molecular Biosciences
Faculty of Science
mary.fletcher@uq.edu.au
+61 7 344 32479

Overview

Professor Mary Fletcher is a natural product organic chemist, and leads the Natural Toxin group within the Centre for Animal Science, Queensland Alliance for Agricultural and Food Innovation (QAAFI). She has 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 is based at the Health and Food Sciences Precinct (Coopers Plains), and her current work focuses on 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 Associate 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).

Research Interests

  • Natural Toxins
    Prof Fletcher's research interests focus on 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 current research is focussed 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. Prof Fletcher currently supervises a number of post-graduate students in the area of natural toxins, and the application of analytical techniques such as liquid chromatography-tandem mass spectrometry (LC-MS/MS) to evaluate and minimise risks associated with these toxins. 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.

Her current research funded by Meat and Livestock Australia (MLA) is focussed on minimising the impacts of plant toxins on Australian livestock production. Some individual cattle are anecdotally recognized as less susceptible to specific plant toxins, and often this increased “resistance” is attributable to previous low dose exposure to the toxin and subsequent enhancement of rumen microbial capacity to deal with or degrade the toxin. This research seeks to capitalise on this 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.

Qualifications

  • BSc, The University of Queensland
  • BSc (Hons), The University of Queensland
  • PhD, The University of Queensland

Publications

View all Publications

Supervision

  • Doctor Philosophy

  • Doctor Philosophy

  • Doctor Philosophy

View all Supervision

Available Projects

  • Consumption of poisonous plants by livestock does not necessarily equal uptake of the toxin, and the approach of the proposed research is to devise strategies to enable toxin breakdown in the cattle rumen before absorption into the bloodstream. This applied industry project is aimed at mitigating the effects of the Pimelea plant toxin simplexin and requires analytical chemistry skills to measure both the toxin and its degradation products. This investigation capitalises on natural rumen response by isolating microbes capable of degrading the simplexin (for use as preventative probiotics), and investigating toxin absorbents and/or biopolymers to foster toxin-degrading microbe populations. The majority of this study will be laboratory based and will utilise both LC-MS/MS and High Resolution Accurate MS to measure both the toxin and its metabolites in these systems. Additional top-up scholarship ($8,000 p.a.) is available for suitable domestic student.

    https://qaafi.uq.edu.au/article/2017/12/mla-fund-more-pimelea-research-develop-rumen-inoculum

  • Pyrrolizidine alkaloids are natural carcinogens present in approximately 3 percent of flowering plants. Internationally it has been reported that such toxins can be found in honey due to transfer of pollen by bees. This project will utilise liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology to investigate the presence of such alkaloids in Queensland honey samples.

View all Available Projects

Publications

Book

Book Chapter

  • Pue, Aisak G., Fletcher, Mary T., Blaney, Barry, Greenhill, Andrew R., Warner, Jeffrey. M., Latifa, Atagazli and Ng, Jack C. (2018). Addressing food insecurity in Papua New Guinea through food safety and sago cropping. Sago palm, multiple contributions to food security and sustainable livelihoods. (pp. 123-137) edited by Hiroshi Ehara, Yukio Toyoda and Dennis V. Johnson. Singapore: Springer Nature. doi: 10.1007/978-981-10-5269-9

  • Pue, Aisak G., Fletcher, Mary T., Blaney, Barry, Greenhill, Andrew R., Warner, Jeffery M., Latifa, Atagazli and Ng, Jack C. (2018). Erratum: Addressing food insecurity in Papua New Guinea through food safety and sago cropping. Sago palm: multiple contributions to food security and sustainable livelihoods. (pp. E1-E1) Singapore, Singapore: Springer Singapore. doi: 10.1007/978-981-10-5269-9_25

  • Fletcher, Mary T. and Barry Blaney (2016). Mycotoxins. Encyclopedia of food grains. Volume 2: nutrition and food grains.. (pp. 290-296) edited by Colin Wrigley, Harold Corke, Koushik Seetharaman and Jon Faubion. Kidlington, Oxford, United Kingdom: Elsevier. doi: 10.1016/B978-0-12-394437-5.00112-1

  • 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.

  • 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.

  • Harvey, Jagger, Gnonlonfin, Benoi, Fletcher, Mary, Fox, Glen, Trowell, Stephen, Berna, Amalia, Nelson, Rebecca and Darnell, Ross (2013). Improving diagnostics for aflatoxin detection. Aflatoxins: finding solutions for improved food safety. (pp. 1-2) Washington, DC, USA: International Food Policy Research Institute. doi: 10.2499/9780896296763

  • 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.

  • 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.

  • 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.

Journal Article

Conference Publication

Edited Outputs

  • 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).

Grants (Administered at UQ)

PhD and MPhil Supervision

Current Supervision

  • Doctor Philosophy — Principal Advisor

  • Doctor Philosophy — Principal Advisor

    Other advisors:

  • Doctor Philosophy — Principal Advisor

  • Doctor Philosophy — Associate Advisor

    Other advisors:

  • Doctor Philosophy — Associate Advisor

  • Doctor Philosophy — Associate Advisor

Completed Supervision

Possible Research Projects

Note for students: The possible research projects listed on this page may not be comprehensive or up to date. Always feel free to contact the staff for more information, and also with your own research ideas.

  • Consumption of poisonous plants by livestock does not necessarily equal uptake of the toxin, and the approach of the proposed research is to devise strategies to enable toxin breakdown in the cattle rumen before absorption into the bloodstream. This applied industry project is aimed at mitigating the effects of the Pimelea plant toxin simplexin and requires analytical chemistry skills to measure both the toxin and its degradation products. This investigation capitalises on natural rumen response by isolating microbes capable of degrading the simplexin (for use as preventative probiotics), and investigating toxin absorbents and/or biopolymers to foster toxin-degrading microbe populations. The majority of this study will be laboratory based and will utilise both LC-MS/MS and High Resolution Accurate MS to measure both the toxin and its metabolites in these systems. Additional top-up scholarship ($8,000 p.a.) is available for suitable domestic student.

    https://qaafi.uq.edu.au/article/2017/12/mla-fund-more-pimelea-research-develop-rumen-inoculum

  • Pyrrolizidine alkaloids are natural carcinogens present in approximately 3 percent of flowering plants. Internationally it has been reported that such toxins can be found in honey due to transfer of pollen by bees. This project will utilise liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology to investigate the presence of such alkaloids in Queensland honey samples.