A Feeding Trial to Investigate Strategies to Mitigate the Impacts of Poisoning in Australian Cattle.

poisoning of cattle causes distinct symptoms and frequently death, attributable to the toxin simplexin. poisoning was induced via addition of ground plant to the daily feed in a three-month trial with Droughtmaster steers. The trial tested four potential mitigation treatments, namely, biochar, activated biochar, bentonite, and a bacterial inoculum, and incorporated negative and positive control groups.

Binding of the plant-derived toxin simplexin to bovine protein kinase C: insights from molecular dynamics.

poisoning of cattle is toxicologically linked to the activation of bovine protein kinase C (PKC) by the plant-derived toxin simplexin. To understand the affinity of PKC for simplexin, we performed molecular dynamics (MD) studies of simplexin, simplexin analogues, and several other activators of PKC. Binding enthalpy calculations indicated that simplexin had the strongest affinity for PKCα-C1B among the activators studied.

Identification of Acid Hydrolysis Metabolites of the Pimelea Toxin Simplexin for Targeted UPLC-MS/MS Analysis.

Pimelea poisoning of cattle is a unique Australian toxic condition caused by the daphnane orthoester simplexin present in native Pimelea pasture plants. Rumen microorganisms have been proposed to metabolise simplexin by enzymatic reactions, likely at the orthoester and epoxide moieties of simplexin, but a metabolic pathway has not been confirmed. This study aimed to investigate this metabolic pathway through the analysis of putative simplexin metabolites.

How is Trehalulose Formed by Australian Stingless Bees? - An Intermolecular Displacement of Nectar Sucrose.

Trehalulose, a rare sucrose isomer, is a dominant sugar in stingless bee honey, with traces of the trisaccharide erlose. Incubating sucrose solutions with macerated stingless bee parts (head, thorax, and abdomen) from , we observed that sucrose isomerization occurs predominantly in the head incubations, with trehalulose constituting 76.2-80.

Unique physicochemical properties and rare reducing sugar trehalulose mandate new international regulation for stingless bee honey.

Stingless bee honey (SBH) of four stingless bee species (Heterotrigona itama, Geniotrigona thoracica, Tetragonula carbonaria, and Tetragonula hockingsi) from two geographic regions (Malaysia and Australia, n = 36) were studied for their physicochemical parameters, including total phenolic and multi-elemental contents. Sugar analysis confirmed the prominent presence of trehalulose in all samples. All SBH failed to meet the CODEX Standard for honey moisture, free acidity, and total fructose plus glucose levels.

Feeding Sugars to Stingless Bees: Identifying the Origin of Trehalulose-Rich Honey Composition.

The beneficial disaccharide, trehalulose, is a feature of stingless bee honey, while not dominant in any other foods. By experimentally feeding sugar solutions to confined colonies of the Australian stingless bee , the origin of trehalulose has now been established. Complete conversion of fed sucrose was observed, by analysis of the honey, forming trehalulose (64-72%) with lesser erlose (18-23%), fructose (9-12%), and minor glucose detected.

Extraction and determination of the Pimelea toxin simplexin in complex plant-polymer biocomposites using ultrahigh-performance liquid chromatography coupled with quadrupole Orbitrap mass spectrometry.

In the present paper, we describe how a robust and fundamental methodology was developed for extraction and determination of a principal natural toxin compound, simplexin, from a series of bulk biocomposites. These complex matrices were fabricated by direct encapsulating either ground plant particles or an ethanolic crude extract of the Australian toxic pasture plant Pimelea trichostachya in the biodegradable polymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Proton nuclear magnetic resonance spectroscopy was initially employed to examine the chemical compositions of these complicated systems.

Toxin Degradation by Rumen Microorganisms: A Review.

Animal feeds may contain exogenous compounds that can induce toxicity when ruminants ingest them. These toxins are secondary metabolites originating from various sources including plants, bacteria, algae and fungi. Animal feed toxins are responsible for various animal poisonings which negatively impact the livestock industry.

Mineral and Trace Element Analysis of Australian/Queensland Honey.

Honey is an extensively utilized sweetener containing sugars and water, together with small quantities of vitamins, minerals, fatty acids, amino acids and proteins. Naturally produced by honeybees () from floral nectar, honey is increasingly sold as a health food product due to its nutritious features. Certain honeys are retailed as premium, trendy products.

A review on Pimelea poisoning of livestock.

Pimelea poisoning of cattle, historically known as St. George Disease or Marree Disease, is a prevailing issue in arid grazing regions of inland Australia. Ingestion of the toxic native Pimelea species that contain the secondary metabolite simplexin, a diterpene orthoester with potent protein kinase C activity, induces diarrhoea, characteristic oedema and potentially fatal right-sided heart failure in cattle.

Stingless bee honey, a novel source of trehalulose: a biologically active disaccharide with health benefits.

Stingless bee (Meliponini) honey has long been considered a high-value functional food, but the perceived therapeutic value has lacked attribution to specific bioactive components. Examination of honey from five different stingless bee species across Neotropical and Indo-Australian regions has enabled for the first time the identification of the unusual disaccharide trehalulose as a major component representing between 13 and 44 g per 100 g of each of these honeys. Trehalulose is an isomer of sucrose with an unusual α-(1 → 1) glucose-fructose glycosidic linkage and known acariogenic and low glycemic index properties.

Analysis of Pyrrolizidine Alkaloids in Queensland Honey: Using Low Temperature Chromatography to Resolve Stereoisomers and Identify Botanical Sources by UHPLC-MS/MS.

Pyrrolizidine alkaloids (PAs) are a diverse group of plant secondary metabolites with known varied toxicity. Consumption of 1,2-unsaturated PAs has been linked to acute and chronic liver damage, carcinogenicity and death, in livestock and humans, making their presence in food of concern to food regulators in Australia and internationally. In this survey, honey samples sourced from markets and shops in Queensland (Australia), were analysed by high-resolution Orbitrap UHPLC-MS/MS for 30 common PAs.

Pyrrolizidine Alkaloids of Blue Heliotrope () and Their Presence in Australian Honey.

Blue heliotrope () is an invasive environmental weed that is widely naturalized in eastern Australia and has been implicated as a source of pyrrolizidine alkaloid (PA) poisoning in livestock. Less well-documented is the potential of such carcinogenic alkaloids to contaminate honey from bees foraging on this plant species. In this study, the PA profile of plant material, determined by HRAM LC-MS/MS, revealed the presence of nine PAs and PA--oxides, including several PAs and PA--oxides of the indicine class, which have not previously been reported.

(4+3) Cycloaddition Reactions of N-Alkyl Oxidopyridinium Ions.

N-Methylation of methyl 5-hydroxynicotinate followed by reaction with a diene in the presence of triethylamine afforded (4+3) cycloadducts in good to excellent yields. High regioselectivity was observed with 1-substituted and 1,2-disubstituted butadienes. Density functional theory calculations indicate that the cycloaddition involves concerted addition of the diene onto the oxidopyridinium ion.

Synthesis and evaluation of anticancer natural product analogues based on angelmarin: targeting the tolerance towards nutrient deprivation.

Inspired by nature: Angelmarin is an anticancer natural product with potent antiausterity activity, that is, selective cytotoxicity towards nutrient-deprived, resistant cancer cells. Through structure-activity relationship studies, three analogues were identified as lead compounds for the develpoment of molecular probes for the investigation of the mode of action and biological targets of the antiausterity compounds.

3,4'-Linked bis(piperidines) related to the haliclonacyclamine class of marine alkaloids: synthesis using crossed-aldol chemistry and preliminary biological evaluations.

Compounds 2-5, incorporating various elements of the 3,4'-bis(piperidine) core associated with the sponge-derived alkaloid haliclonacyclamine A (HA, 1), have been prepared through, inter alia, aldol-type reactions of N-substituted piperidin-4-ones and certain derivatives. Screening of these compounds in various assays, including an ecological one, reveals that compound 5 exhibits allelochemical properties similar to those associated with HA itself.

Selective manipulation of steroid hydroxyl groups with boronate esters: Efficient access to antigenic C-3 linked steroid-protein conjugates and steroid sulfate standards for drug detection.

The temporary protection of 17alpha-alkyl-5alpha-androstane-3beta,16beta,17beta triols as boronate esters is an efficient method for their regioselective functionalisation. This has been applied to the synthesis of protein-steroid conjugates 7-10 suitable for the development of immunoassays targeting classes of steroids banned from competition in Australian horse racing and other sports. The synthesis of steroids sulfate conjugates 42 and 44 for use as reference standards is also reported.

Enantioselective total synthesis of (-)-dactylolide.

[reaction: see text] The enantioselective total synthesis of (-)-dactylolide is reported. The absolute stereochemistry of the tetrahydropyran was established by catalytic asymmetric Jacobsen hetero-Diels-Alder reaction. The remote C19 stereocenter was introduced by a sequence of chelation-controlled Grignard addition and Ireland-Claisen rearrangement.

Analysis of anabolic steroids in the horse: development of a generic ELISA for the screening of 17alpha-alkyl anabolic steroid metabolites.

Due to the potential for misuse of a wide range of anabolic steroids in horse racing, a screening test to detect multiple compounds, via a common class of metabolites, would be a valuable forensic tool. An enzyme-linked immunosorbent assay (ELISA) has been developed to detect 17alpha-alkyl anabolic steroid metabolites in equine urine. 16beta-Hydroxymestanolone (16beta,17beta-dihydroxy-17alpha-methyl-5alpha-androstan-3-one) was synthesised in six steps from commercially available epiandrosterone (3beta-hydroxy-5alpha-androstan-17-one).

Synthesis of the sialic acid (-)-KDN and certain epimers from (-)-3-dehydroshikimic acid or (-)-quinic acid.

(-)-3-Dehydroshikimic acid (3-DHS, 4), a C(7)-building block now available in large quantity from corn syrup, has been converted into the sialic acid (-)-KDN (3) as well as its C-7- and C-8-epimers. (-)-Quinic acid can be used for the same purpose. [structure: see text]

Insect chemistry and chirality.

Examination of the chemistry of a number of Australian insect species provided examples of unusual structures and encouraged determinations of their absolute stereochemistry by stereocontrolled syntheses and chromatographic comparisons. Inter alia, studies with the fruit-spotting bug (Amblypelta nitida), certain parasitic wasps (Biosteres sp.), the aposematic shield bug (Cantao parentum), and various species of scarab grubs are summarized.