ORCID Profile
0000-0002-3305-6954
Current Organisation
University of New England
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Publisher: Wiley
Date: 05-03-2015
DOI: 10.1002/DTA.1782
Abstract: The hydrolysis of sulfate ester conjugates is frequently required prior to analysis for a range of analytical techniques including gas chromatography-mass spectrometry (GC-MS). Sulfate hydrolysis may be achieved with commercial crude arylsulfatase enzyme preparations such as that derived from Helix pomatia but these contain additional enzyme activities such as glucuronidase, oxidase, and reductase that make them unsuitable for many analytical applications. Strong acid can also be used to hydrolyze sulfate esters but this can lead to analyte degradation or increased matrix interference. In this work, the heterologously expressed and purified arylsulfatase from Pseudomonas aeruginosa is shown to promote the mild enzyme-catalyzed hydrolysis of a range of steroid sulfates. The substrate scope of this P. aeruginosa arylsulfatase hydrolysis is compared with commercial crude enzyme preparations such as that derived from H. pomatia. A detailed kinetic comparison is reported for selected ex les. Hydrolysis in a urine matrix is demonstrated for dehydroepiandrosterone 3-sulfate and epiandrosterone 3-sulfate. The purified P. aeruginosa arylsulfatase contains only sulfatase activity allowing for the selective hydrolysis of sulfate esters in the presence of glucuronide conjugates as demonstrated in the short three-step chemoenzymatic synthesis of 5α-androstane-3β,17β-diol 17-glucuronide (ADG, 1) from epiandrosterone 3-sulfate. The P. aeruginosa arylsulfatase is readily expressed and purified (0.9 g per L of culture) and thus provides a new and selective method for the hydrolysis of steroid sulfate esters in analytical s le preparation.
Publisher: Wiley
Date: 18-11-2017
DOI: 10.1002/DTA.2112
Abstract: In recent years, the potential for anabolic steroid abuse in equine sports has increased due to the growing availability of designer steroids. These compounds are readily accessible online in 'dietary' or 'nutritional' supplements and contain steroidal compounds which have never been tested or approved as veterinary agents. They typically have unusual structures or substitution and as a result may pass undetected through current anti-doping screening protocols, making them a significant concern for the integrity of the industry. Despite considerable focus in human sports, until recently there has been limited investigation into these compounds in equine systems. To effectively respond to the threat of designer steroids, a detailed understanding of their metabolism is needed to identify markers and metabolites arising from their misuse. A summary of the literature detailing the metabolism of these compounds in equine systems is presented with an aim to identify metabolites suitable for incorporation into screening protocols by anti-doping laboratories. The future of equine anti-doping research is likely to be guided by the incorporation of alternate testing matrices into routine screening, the improvement of in vitro technologies that can mimic in vivo equine metabolism, and the improvement of instrumentation or analytical methods that allow for the development of untargeted screening, and metabolomics approaches for use in anti-doping screening protocols. Copyright © 2016 John Wiley & Sons, Ltd.
Publisher: Wiley
Date: 18-07-2018
DOI: 10.1002/DTA.2224
Abstract: In vitro technologies provide the capacity to study drug metabolism where in vivo studies are precluded due to ethical or financial constraints. The metabolites generated by in vitro studies can assist anti-doping laboratories to develop protocols for the detection of novel substances that would otherwise evade routine screening efforts. In addition, professional bodies such as the Association of Official Racing Chemists (AORC) currently permit the use of in-vitro-derived reference materials for confirmation purposes providing additional impetus for the development of cost effective in vitro metabolism platforms. In this work, alternative conditions for in vitro phase II sulfation using human, equine or canine liver S9 fraction were developed, with adenosine triphosphate (ATP) and sodium sulfate in place of the expensive and unstable co-factor 3'-phosphoadenosine-5'-phosphosulfate (PAPS), and employed for the generation of six representative steroidal sulfates. Using these conditions, the equine in vitro phase II metabolism of the synthetic or so-called designer steroid furazadrol ([1',2']isoxazolo[4',5':2,3]-5α-androstan-17β-ol) was investigated, with ATP and Na
Publisher: American Association for the Advancement of Science (AAAS)
Date: 19-05-2017
Abstract: Biotic interactions underlie ecosystem structure and function, but predicting interaction outcomes is difficult. We tested the hypothesis that biotic interaction strength increases toward the equator, using a global experiment with model caterpillars to measure predation risk. Across an 11,660-kilometer latitudinal gradient spanning six continents, we found increasing predation toward the equator, with a parallel pattern of increasing predation toward lower elevations. Patterns across both latitude and elevation were driven by arthropod predators, with no systematic trend in attack rates by birds or mammals. These matching gradients at global and regional scales suggest consistent drivers of biotic interaction strength, a finding that needs to be integrated into general theories of herbivory, community organization, and life-history evolution.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 18-03-2022
Abstract: Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by s ling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale.
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.JPBA.2016.02.031
Abstract: Furazadrol ([1',2']isoxazolo[4',5':2,3]-5α-androstan-17β-ol) is a designer anabolic androgenic steroid that is readily available via the internet. It contains an isoxazole fused to the steroid A-ring which offers metabolic stability and noteworthy anabolic activity raising concerns over the potential for abuse of this compound in equine sports. The metabolism of furazadrol was studied by in vivo and in vitro methods for the first time. Urinary furazadrol 17-sulfate and furazadrol 17-glucuronide metabolites were detected in vivo after a controlled administration and compared with synthetically-derived reference materials in order to confirm their identities. They were quantified to establish the excretion profile and a suitable limit of detection. Minor metabolites were also detected, including epifurazadrol, hydroxylated furazadrol, and hydroxylated and oxidised furazadrol, present as the sulfate and glucuronide conjugates. Phase II metabolites were subjected to enzymatic hydrolysis by Escherichia coli β-glucuronidase and Pseudomonas aeruginosa arylsulfatase to further confirm the identity of the corresponding phase I metabolites. The metabolism profile was compared to the products obtained from an in vitro phase I metabolism study, with all but two of the minor in vivo phase I metabolites observed in the in vitro system. These investigations identify the key urinary metabolites of furazadrol following oral administration, which can be incorporated into anti-doping screening and confirmation procedures.
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/PC000120
Abstract: Remnants of an endangered community, Cumberland Plain Woodlands on shale, were studied in order to 1) investigate the conflict between the needs of legislation to define parameters of protected communities in a precise manner and the spatial variation in communities, and 2) to define floristic groupings in the Cumberland Plain Woodlands based on all plant species. Sites previously classified as Grey Box Woodland, Grey Box Ironbark Woodland and Spotted Gum Woodland map units were surveyed and compared to the same classification applied by one of the authors. Differences were evident, but both classifications showed statistically significant differences between map units, suggesting that although each classification is valid, the differences between these map units cannot be consistently applied. Canopy species were not useful descriptors of the community as they grouped differently to both the full species list and the understorey species. A significantly different community occurring at the transition between shale and sandstone in Holsworthy Military Area was identified, suggesting the importance of this area to the conservation of variability in communities in this area. The use of multivariate techniques to describe levels of variation in communities is discussed and a potential method for using a standard level of similarity to classify vegetation communities is introduced as a mechanism for defining communities using some consistent technique.
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/WF19027
Abstract: Potential impacts of soil temperatures in a post-fire environment were examined for seeds of legume species with a physical seed dormancy typically found in the eucalypt communities in eastern Australia. Soil temperatures in a post-fire environment may be elevated owing to increased solar radiation and this may influence germination of species with soil-stored seed banks. Seeds were heated at 50, 60 or 70°C, with one unheated control, for 3h per day for 5 days to simulate soil temperatures where canopy gaps existed. More germination of small-seeded species (& .6mg) occurred owing to changes in simulated soil temperatures than large-seeded species (& .0mg). Temperatures up to 70°C significantly increased the germination of species with relatively small-sized seeds than large-seeded species (& °C). This study demonstrated that small-seeded species are able to germinate across a range of temperatures (50–70°C) and can have dormancy broken either during the passage of a fire, or after fire from increased solar radiation, potentially resulting in the decline of the post-fire residual soil seed bank. In contrast, post-fire germination of large-seeded species may be dependent solely on the degree of soil heating during the passage of fire and the species may have a relatively stable residual soil seed bank thereafter.
Publisher: Elsevier BV
Date: 12-2014
DOI: 10.1016/J.STEROIDS.2014.09.006
Abstract: Steroid sulfates are a major class of steroid metabolite that are of growing importance in fields such as anti-doping analysis, the detection of residues in agricultural produce or medicine. Despite this, many steroid sulfate reference materials may have limited or no availability h ering the development of analytical methods. We report simple protocols for the rapid synthesis and purification of steroid sulfates that are suitable for adoption by analytical laboratories. Central to this approach is the use of solid-phase extraction (SPE) for purification, a technique routinely used for s le preparation in analytical laboratories around the world. The sulfate conjugates of sixteen steroid compounds encompassing a wide range of steroid substitution patterns and configurations are prepared, including the previously unreported sulfate conjugates of the designer steroids furazadrol (17β-hydroxyandrostan[2,3-d]isoxazole), isofurazadrol (17β-hydroxyandrostan[3,2-c]isoxazole) and trenazone (17β-hydroxyestra-4,9-dien-3-one). Structural characterization data, together with NMR and mass spectra are reported for all steroid sulfates, often for the first time. The scope of this approach for small scale synthesis is highlighted by the sulfation of 1μg of testosterone (17β-hydroxyandrost-4-en-3-one) as monitored by liquid chromatography-mass spectrometry (LCMS).
Publisher: Wiley
Date: 20-11-2019
DOI: 10.1111/AEC.12674
Publisher: Wiley
Date: 23-10-2020
DOI: 10.1111/PHEN.12310
Publisher: Wiley
Date: 04-02-2020
DOI: 10.1002/DTA.2769
Abstract: Hemapolin (2α,3α-epithio-17α-methyl-5α-androstan-17β-ol) is a designer steroid that is an ingredient in several "dietary" and "nutritional" supplements available online. As an unusual chemical modification to the steroid A-ring could allow this compound to pass through antidoping screens undetected, the metabolism of hemapolin was investigated by an in vivo equine drug administration study coupled with GC-MS analysis. Following administration of synthetically prepared hemapolin to a thoroughbred horse, madol (17α-methyl-5α-androst-2-en-17β-ol), reduced and dihydroxylated madol (17α-methyl-5α-androstane-2β,3α,17β-triol), and the isomeric enone metabolites 17β-hydroxy-17α-methyl-5α-androst-3-en-2-one and 17β-hydroxy-17α-methyl-5α-androst-2-en-4-one, were detected and confirmed in equine urine extracts by comparison with a library of synthetically derived reference materials. A number of additional madol derivatives derived from hydroxylation, dihydroxylation, and trihydroxylation were also detected but not fully identified by this approach. A yeast cell-based androgen receptor bioassay of available reference materials showed that hemapolin and many of the metabolites identified by this study were potent activators of the equine androgen receptor. This study reveals the metabolites resulting from the equine administration of the androgen hemapolin that can be incorporated into routine GC-MS antidoping screening and confirmation protocols to detect the illicit use of this agent in equine sports.
Publisher: Wiley
Date: 21-05-2019
DOI: 10.1111/AEN.12399
Publisher: Wiley
Date: 18-07-2021
DOI: 10.1002/DTA.3128
Abstract: S les of the ‘dietary supplement’ Furazadrol sourced through the internet have been reported to contain the designer anabolic androgenic steroids [1′,2′]isoxazolo[4′,5′:2,3]‐5α‐androstan‐17β‐ol (furazadrol F ) and [1′,2′]isoxazolo[4′,3′:2,3]‐5α‐androstan‐17β‐ol (isofurazadrol IF ). These steroids contain an isoxazole fused to the A‐ring and were designed to offer anabolic activity while evading detection, raising concerns over the potential for abuse of this preparation in sports. The metabolism of Furazadrol ( F : IF , 10:1) was studied by in vivo methods in greyhounds. Urinary phase II Furazadrol metabolites were detected as glucuronides after a controlled administration. These phase II metabolites were subjected to enzymatic hydrolysis by Escherichia coli β‐glucuronidase to afford the corresponding phase I metabolites. Using a library of synthetically derived reference materials, the identities of seven urinary Furazadrol metabolites were confirmed. Major confirmed metabolites were isofurazadrol IF , 4α‐hydroxyfurazadrol 4α‐HF and 16α‐hydroxy oxidised furazadrol 16α‐HOF , whereas the minor confirmed metabolites were furazadrol F , 4β‐hydroxyfurazadrol 4β‐HF , 16β‐hydroxyfurazadrol 16β‐HF and 16β‐hydroxy oxidised furazadrol 16β‐HOF . One major hydroxyfurazadrol and two dihydroxyfurazadrol metabolites remained unidentified. Qualitative excretion profiles, limits of detection and extraction recoveries were established for furazadrol F and major confirmed metabolites. These investigations identify the key urinary metabolites of Furazadrol following oral administration, which can be incorporated into routine screening by anti‐doping laboratories to aid the regulation of greyhound racing.
Publisher: Wiley
Date: 23-06-2016
DOI: 10.1002/DTA.1832
Abstract: In 2012, seized capsules containing white powder were analyzed to show the presence of unknown steroid-related compounds. Subsequent gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) investigations identified a mixture of 3α- and 3β- isomers of the novel compound 3-chloro-17α-methyl-5α-androstan-17β-ol. Synthesis of authentic reference materials followed by comparison of NMR, GC-MS and gas chromatography-tandem mass spectrometry (GC-MS/MS) data confirmed the finding of a new 'designer' steroid. Furthermore, in vitro androgen bioassays showed potent activity highlighting the potential for doping using this steroid. Due to the potential toxicity of the halogenated steroid, in vitro metabolic investigations of 3α-chloro-17α-methyl-5α-androstan-17β-ol using equine and human S9 liver fractions were performed. For equine, GC-MS/MS analysis identified the diagnostic 3α-chloro-17α-methyl-5α-androstane-16α,17β-diol metabolite. For human, the 17α-methyl-5α-androstane-3α,17β-diol metabolite was found. Results from these studies were used to verify the ability of GC-MS/MS precursor-ion scanning techniques to support untargeted detection strategies for designer steroids in anti-doping analyses. Copyright © 2015 John Wiley & Sons, Ltd.
Publisher: Scientific Research Publishing, Inc.
Date: 2012
No related grants have been discovered for Sarah Hill.