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Simone Vassiliadis
Agriculture Victoria, AgriBio Centre for AgriBioscience, Bundoora, VIC 3083, Australia

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Journal article
Published: 07 November 2019 in Toxins
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The rapid identification and quantitation of alkaloids produced by Epichloë endophyte-infected pasture grass is important for the agricultural industry. Beneficial alkaloids, such as peramine, provide the grass with enhanced insect protection. Conversely, ergovaline and lolitrem B can negatively impact livestock. Currently, a single validated method to measure these combined alkaloids in planta does not exist. Here, a simple two-step extraction method was developed for Epichloë-infected perennial ryegrass (Lolium perenne L.). Peramine, ergovaline and lolitrem B were quantified using liquid chromatography–mass spectrometry (LC–MS). Alkaloid linearity, limit of detection (LOD), limit of quantitation (LOQ), accuracy, precision, selectivity, recovery, matrix effect and robustness were all established. The validated method was applied to eight different ryegrass-endophyte symbiota. Robustness was established by comparing quantitation results across two additional instruments; a triple quadruple mass spectrometer (QQQ MS) and by fluorescence detection (FLD). Quantitation results were similar across all three instruments, indicating good reproducibility. LOQ values ranged from 0.8 ng/mL to 6 ng/mL, approximately one hundred times lower than those established by previous work using FLD (for ergovaline and lolitrem B), and LC–MS (for peramine). This work provides the first highly sensitive quantitative LC–MS method for the accurate and reproducible quantitation of important endophyte-derived alkaloids.

ACS Style

Simone Vassiliadis; Aaron C. Elkins; Priyanka Reddy; Kathryn M. Guthridge; German C. Spangenberg; Simone J. Rochfort. A Simple LC–MS Method for the Quantitation of Alkaloids in Endophyte-Infected Perennial Ryegrass. Toxins 2019, 11, 649 .

AMA Style

Simone Vassiliadis, Aaron C. Elkins, Priyanka Reddy, Kathryn M. Guthridge, German C. Spangenberg, Simone J. Rochfort. A Simple LC–MS Method for the Quantitation of Alkaloids in Endophyte-Infected Perennial Ryegrass. Toxins. 2019; 11 (11):649.

Chicago/Turabian Style

Simone Vassiliadis; Aaron C. Elkins; Priyanka Reddy; Kathryn M. Guthridge; German C. Spangenberg; Simone J. Rochfort. 2019. "A Simple LC–MS Method for the Quantitation of Alkaloids in Endophyte-Infected Perennial Ryegrass." Toxins 11, no. 11: 649.

Journal article
Published: 13 August 2019 in Metabolites
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Lentils are a high-protein plant food and a valuable source of human nutrition, particularly in the Indian subcontinent. However, beyond sustenance, there is evidence that the consumption of lentils (and legumes in general) is associated with decreased risk of diseases, such as diabetes and cardiovascular disease. Lentils contain health-promoting phytochemicals, such as trigonelline and various polyphenolics. Fourteen lentil genotypes were grown at three locations to explore the variation in phytochemical composition in hulls and cotyledons. Significant differences were measured between genotypes and environments, with some genotypes more affected by environment than others. However, there was a strong genetic effect which indicated that future breeding programs could breed for lentils that product more of these health-promoting phytochemicals.

ACS Style

Simone Rochfort; Simone Vassiliadis; Pankaj Maharjan; Jason Brand; Joe Panozzo. NMR Based Metabolomic Analysis of Health Promoting Phytochemicals in Lentils. Metabolites 2019, 9, 168 .

AMA Style

Simone Rochfort, Simone Vassiliadis, Pankaj Maharjan, Jason Brand, Joe Panozzo. NMR Based Metabolomic Analysis of Health Promoting Phytochemicals in Lentils. Metabolites. 2019; 9 (8):168.

Chicago/Turabian Style

Simone Rochfort; Simone Vassiliadis; Pankaj Maharjan; Jason Brand; Joe Panozzo. 2019. "NMR Based Metabolomic Analysis of Health Promoting Phytochemicals in Lentils." Metabolites 9, no. 8: 168.

Review
Published: 27 May 2019 in Toxins
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Indole-diterpenes are an important class of chemical compounds which can be unique to different fungal species. The highly complex lolitrem compounds are confined to Epichloë species, whilst penitrem production is confined to Penicillium spp. and Aspergillus spp. These fungal species are often present in association with pasture grasses, and the indole-diterpenes produced may cause toxicity in grazing animals. In this review, we highlight the unique structural variations of indole-diterpenes that are characterised into subgroups, including paspaline, paxilline, shearinines, paspalitrems, terpendoles, penitrems, lolitrems, janthitrems, and sulpinines. A detailed description of the unique biological activities has been documented where even structurally related compounds have displayed unique biological activities. Indole-diterpene production has been reported in two classes of ascomycete fungi, namely Eurotiomycetes (e.g., Aspergillus and Penicillium) and Sordariomycetes (e.g., Claviceps and Epichloë). These compounds all have a common structural core comprised of a cyclic diterpene skeleton derived from geranylgeranyl diphosphate (GGPP) and an indole moiety derived from tryptophan. Structure diversity is generated from the enzymatic conversion of different sites on the basic indole-diterpene structure. This review highlights the wide-ranging biological versatility presented by the indole-diterpene group of compounds and their role in an agricultural and pharmaceutical setting.

ACS Style

Priyanka Reddy; Kathryn Guthridge; Simone Vassiliadis; Joanne Hemsworth; Inoka Hettiarachchige; German Spangenberg; Simone Rochfort. Tremorgenic Mycotoxins: Structure Diversity and Biological Activity. Toxins 2019, 11, 302 .

AMA Style

Priyanka Reddy, Kathryn Guthridge, Simone Vassiliadis, Joanne Hemsworth, Inoka Hettiarachchige, German Spangenberg, Simone Rochfort. Tremorgenic Mycotoxins: Structure Diversity and Biological Activity. Toxins. 2019; 11 (5):302.

Chicago/Turabian Style

Priyanka Reddy; Kathryn Guthridge; Simone Vassiliadis; Joanne Hemsworth; Inoka Hettiarachchige; German Spangenberg; Simone Rochfort. 2019. "Tremorgenic Mycotoxins: Structure Diversity and Biological Activity." Toxins 11, no. 5: 302.

Original article
Published: 27 September 2018 in Metabolomics
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The aphid Rhopalosiphum padi L. is a vector of Barley yellow dwarf virus (BYDV) in wheat and other economically important cereal crops. Increased atmospheric CO2 has been shown to alter plant growth and metabolism, enhancing BYDV disease in wheat. However, the biochemical influences on aphid metabolism are not known. This work aims to determine whether altered host-plant quality, influenced by virus infection and elevated CO2, impacts aphid weight and metabolism. Untargeted 1H NMR metabolomics coupled with multivariate statistics were employed to profile the metabolism of R. padi reared on virus-infected and non-infected (sham-inoculated) wheat grown under ambient CO2 (aCO2, 400 µmol mol-1) and future, predicted elevated CO2 (eCO2, 650 µmol mol-1) concentrations. Un-colonised wheat was also profiled to observe changes to host-plant quality (i.e., amino acids and sugars). The direct impacts of virus or eCO2 were compared. Virus presence increased aphid weight under aCO2 but decreased weight under eCO2; whilst eCO2 increased non-viruliferous (sham) aphid weight but decreased viruliferous aphid weight. Discriminatory metabolites due to eCO2 were succinate and sucrose (in sham wheat), glucose, choline and betaine (in infected wheat), and threonine, lactate, alanine, GABA, glutamine, glutamate and asparagine (in aphids), irrespective of virus presence. Discriminatory metabolites due to virus presence were alanine, GABA, succinate and betaine (in wheat) and threonine and lactate (in aphids), irrespective of CO2 treatment. This study confirms that virus and eCO2 alter host-plant quality, and these differences are reflected by aphid weight and metabolism.

ACS Style

Simone Vassiliadis; Kim M. Plummer; Kevin S. Powell; Simone J. Rochfort. Elevated CO2 and virus infection impacts wheat and aphid metabolism. Metabolomics 2018, 14, 133 .

AMA Style

Simone Vassiliadis, Kim M. Plummer, Kevin S. Powell, Simone J. Rochfort. Elevated CO2 and virus infection impacts wheat and aphid metabolism. Metabolomics. 2018; 14 (10):133.

Chicago/Turabian Style

Simone Vassiliadis; Kim M. Plummer; Kevin S. Powell; Simone J. Rochfort. 2018. "Elevated CO2 and virus infection impacts wheat and aphid metabolism." Metabolomics 14, no. 10: 133.