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Noel W. Davies - One of the best experts on this subject based on the ideXlab platform.
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Triacylglycerol Estolides, a New Class of Mammalian Lipids, in the Paracloacal Gland of the Brushtail Possum (Trichosurus vulpecula)
Lipids, 2015Co-Authors: Noel W. Davies, David S. Nichols, Bernie J. McleodAbstract:The paracloacal glands are the most prevalent scent glands in marsupials, and previous investigation of their secretions in the Brushtail Possum ( Trichosurus vulpecula ) has identified many odorous compounds together with large amounts of neutral lipids. We have examined the lipids by LC–MS, generating ammonium adducts of acylglycerols by electrospray ionisation. Chromatograms showed a complex mixture of coeluting acylglycerols, with m / z from about 404 to 1048. Plots of single [M + NH_4]^+ ions showed three groups of lipids clearly separated by retention time. MS–MS enabled triacylglycerols and diacylglycerol ethers to be identified from neutral losses and formation of diacylglycerols and other product ions. The earliest-eluting lipids were found to be triacylglycerol estolides, in which a fourth fatty acid forms an ester link with a hydroxy fatty acid attached to the glycerol chain. This is the first report of triacylglycerol estolides in animals. They form a complex mixture with the triacylglycerols and diacylglycerol ethers of lipids with short- and long-chain fatty acids with varying degrees of unsaturation. This complexity suggests a functional role, possibly in social communication.
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Scent Chemicals of the Brushtail Possum, Trichosurus vulpecula
Journal of Chemical Ecology, 2012Co-Authors: Noel W. Davies, Natasha L. WigginsAbstract:The common Brushtail Possum ( Trichosurus vulpecula ) is the most widespread browsing marsupial in Australia, where it occupies woodland, agricultural, and urban environments. Following its introduction into New Zealand in the 19th century it has become a major feral pest, threatening native forests. The adaptability of the Possum is thought to be due in part to its social organization, in which chemical communication is important. Possums have cloacal glands and exhibit related marking behavior. This study sought to characterize the chemicals involved in scent marking. Swabs were taken of the cloacal region of 15 Possums (5 females, 10 males) from north-eastern Tasmania and analyzed by gas chromatography–mass spectrometry. There was a large number of compounds present, including 81 branched and unbranched, and saturated and unsaturated, fatty acids (C_4–C_15) and alcohols (C_6–C_26); 27 esters of 2,6- and 2,7-dimethyloctanol; 29 esters of formic acid; 39 sulfur compounds including S_8 and a series of dialkyl disulfides, trisulfides, and tetrasulfides (C_4–C_10); and several alkylglycerol ethers. Many of these cloacal compounds are new to biology. There was considerable individual variability in the relative amounts of compounds found, and no evident sex differences, although the study was not designed to test this. This pattern suggests that these compounds may be acting collectively as a signature mixture of semiochemicals, carrying information on the individual, its kinship, and physiological and social status. This is the first detailed description of putative semiochemicals in any marsupial species.
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Pharmacokinetics of 1,8-cineole, a dietary toxin, in the Brushtail Possum (Trichosurus vulpecula): significance for feeding.
Xenobiotica, 2007Co-Authors: Stuart Mclean, Rebecca Boyle, Sue Brandon, Noel W. Davies, J. S. SorensenAbstract:Cineole (cineole) is a Eucalyptus leaf toxin that defends against predation by herbivores such as the Brushtail Possum (Trichosurus vulpecula). The aim of the current study was to characterize the pharmacokinetics of cineole in the Possum to improve understanding about how Possums can avoid cineole toxicity when eating a Eucalyptus diet. Nine male Possums were trapped in the wild and acclimated to captivity; a subcutaneous port was then implanted for venous blood sampling. Cineole was administered intravenously (10 and 15 mg kg -1 ) via a lateral tail vein and orally (30, 100 and 300 mg kg -1 ) by gavage, and blood concentrations of cineole and its metabolites were determined by gas chromatography. Cineole had a large terminal volume of distribution (Vz ¼ 27 l kg -1 ) and a high clearance (43 ml min -1 kg -1 ), equal to hepatic blood flow. The terminal half-life was approximately 7 h. Oral bioavailability was low (F ¼ 0.05) after low doses, but increased tenfold with dose, probably due to saturable first-pass metabolism. These findings indicate that when Possums feed on a cineole diet, they eat until the cineole consumed is sufficient to saturate pre-systemic metabolism, leading to a rapid rise in bioavailability and cineole blood levels, and a cessation of the feeding bout. This is the first report on the pharmacokinetics of a dietary toxin in a wild herbivore, and provides insights into the interactions between the blood concentration of a plant secondary metabolite and the browsing behaviour of a herbivore.
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application of solid phase microextraction to the quantitative analysis of 1 8 cineole in blood and expired air in a eucalyptus herbivore the Brushtail Possum trichosurus vulpecula
Journal of Chromatography B, 2002Co-Authors: Rebecca Boyle, G. J. Pass, Stuart Mclean, Sue Brandon, Noel W. DaviesAbstract:We have developed two solid-phase microextraction (SPME) methods, coupled with gas chromatography, for quantitatively analysing the major Eucalyptus leaf terpene, 1,8-cineole, in both expired air and blood from the common Brushtail Possum (Trichosurus vulpecula). In-line SPME sampling (5 min at 20 °C room temperature) of excurrent air from an expiratory chamber containing a Possum dosed orally with 1,8-cineole (50 mg/kg) allowed real-time semi-quantitative measurements reflecting 1,8-cineole blood concentrations. Headspace SPME using 50 il whole blood collected from Possums dosed orally with 1,8-cineole (30 mg/kg) resulted in excellent sensitivity (quantitation limit 1 ng/ml) and reproducibility. Blood concentrations ranged between 1 and 1380 ng/ml. Calibration curves were prepared for two concentration ranges (0.05–10 and 10–400 ng/50 il) for the analysis of blood concentrations. Both calibration curves were linear (r2=0.999 and 0.994, respectively) and the equations for the two concentration ranges were consistent.
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microsomal metabolism of the terpene 1 8 cineole in the common Brushtail Possum trichosurus vulpecula koala phascolarctos cinereus rat and human
Xenobiotica, 2001Co-Authors: G. J. Pass, Stuart Mclean, Ieva Stupans, Noel W. DaviesAbstract:1. This study reports on the pathways of metabolism and enzyme kinetics of the Eucalyptus terpene, 1,8-cineole, by liver microsomes from the Brushtail Possum (Trichosurus vulpecula) and koala (Phascolarctos cinereus) (animals that normally include this terpene in their diet), rat and human. 2. The rank order of the ability to metabolize 1,8-cineole with respect to overall 1,8-cineole intrinsic clearance (CL'int = Vmax/Km in µl mg protein-1 min-1) was koala (188) > Possum (181) >>rat (28) > human (12). This order supports the hypothesis that adaptation to a Eucalyptus diet involves enhanced metabolism of terpenes. 3. The metabolism of 1,8-cineole was also studied in the liver from Brushtail Possum pretreated with a mixture of terpenes, which have previously been shown to induce cytochrome P450 enzymes. Rats were pretreated with the same mixture of terpenes or phenobarbitone. 4. Terpene pretreatment more than doubled the CL'int of 1,8-cineole by Brushtail Possum liver microsomes (from 180 to 394...
Stuart Mclean - One of the best experts on this subject based on the ideXlab platform.
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Scent glands of the common Brushtail Possum (Trichosurus vulpecula)
New Zealand Journal of Zoology, 2014Co-Authors: Stuart McleanAbstract:The common Brushtail Possum (Trichosurus vulpecula) is an important browsing herbivore in its native Australia and in New Zealand, where it has become a major introduced pest. Possums exhibit marking behaviour, and have specialised scent glands, indicating that they use olfactory communication for social interactions. This review summarises what is known of the scent glands of the Possum and some other marsupials. Although the anatomy and histology of the glands has been well-described, the composition of their secretions is only beginning to be characterised, and very little is known about their physiological control and role in Possum biology.
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Pharmacokinetics of 1,8-cineole, a dietary toxin, in the Brushtail Possum (Trichosurus vulpecula): significance for feeding.
Xenobiotica, 2007Co-Authors: Stuart Mclean, Rebecca Boyle, Sue Brandon, Noel W. Davies, J. S. SorensenAbstract:Cineole (cineole) is a Eucalyptus leaf toxin that defends against predation by herbivores such as the Brushtail Possum (Trichosurus vulpecula). The aim of the current study was to characterize the pharmacokinetics of cineole in the Possum to improve understanding about how Possums can avoid cineole toxicity when eating a Eucalyptus diet. Nine male Possums were trapped in the wild and acclimated to captivity; a subcutaneous port was then implanted for venous blood sampling. Cineole was administered intravenously (10 and 15 mg kg -1 ) via a lateral tail vein and orally (30, 100 and 300 mg kg -1 ) by gavage, and blood concentrations of cineole and its metabolites were determined by gas chromatography. Cineole had a large terminal volume of distribution (Vz ¼ 27 l kg -1 ) and a high clearance (43 ml min -1 kg -1 ), equal to hepatic blood flow. The terminal half-life was approximately 7 h. Oral bioavailability was low (F ¼ 0.05) after low doses, but increased tenfold with dose, probably due to saturable first-pass metabolism. These findings indicate that when Possums feed on a cineole diet, they eat until the cineole consumed is sufficient to saturate pre-systemic metabolism, leading to a rapid rise in bioavailability and cineole blood levels, and a cessation of the feeding bout. This is the first report on the pharmacokinetics of a dietary toxin in a wild herbivore, and provides insights into the interactions between the blood concentration of a plant secondary metabolite and the browsing behaviour of a herbivore.
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Constraint of feeding by chronic ingestion of 1,8-cineole in the Brushtail Possum (Trichosurus vulpecula).
Journal of Chemical Ecology, 2004Co-Authors: Rebecca Boyle, Stuart McleanAbstract:Eucalyptus leaf-eating marsupials such as the Brushtail Possum (Trichosurus vulpecula) ingest large amounts of terpenes, especially 1,8-cineole (cineole)—the major component of many eucalyptus oils. Brushtail Possums were acclimated to a non-Eucalyptus diet with increasing concentrations of cineole (0.5–4.0% wet weight) added over 18 d. We measured food and cineole consumption and urinary metabolites of cineole. Food intake decreased with cineole content, indicating that it was constrained by the maximum tolerable intake of cineole that was 3.8 ± 0.2 g kg−1 or 5.2 ± 0.3 g kg−0.75 (mean ± SE, N = 6). The pattern of metabolites was similar at all cineole intakes (56% hydroxycineolic acids, 27% cineolic acids, 13% hydroxycineoles, and 4% dihydroxycineoles). In another experiment, Possums maintained on artificial diet were abruptly presented with 4% cineole for 5 d. Food intake fell by 45 ± 6% (mean ± SE, N = 6) and mean cineole intake was 2.9 ± 0.3 g kg−1. There was evidence of induction of secondary oxidative pathways, as hydroxycineoles were the major metabolites (48% total) on the first day, but rapidly dropped to 15% on subsequent days as the acid metabolites increased. These findings indicate that ingestion of cineole is not constrained by selective saturation of individual enzymes involved in its multiple pathways of oxidation, but rather the total detoxification capacity appears to limit feeding on a cineole diet.
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effects of two plant secondary metabolites cineole and gallic acid on nightly feeding patterns of the common Brushtail Possum
Journal of Chemical Ecology, 2003Co-Authors: Natasha L. Wiggins, Stuart Mclean, Clare Mcarthur, Rebecca BoyleAbstract:We investigated effects of two plant secondary metabolites (PSMs), cineole and gallic acid, on the nightly feeding behavior of the common Brushtail Possum (Trichosurus vulpecula), a generalist folivore. We tested whether Possums altered their feeding behavior in response to increasing levels of cineole, a dietary terpene. Possums were fed artificial diets containing three levels of cineole; zero (basal diet), medium (6.8% of total dry matter, DM), and high (15.3% DM). In another experiment, we introduced gallic acid, a dietary phenolic, into the diets. Possums were offered a Choice PSM diet (cineole and gallic acid diets simultaneously) or a No-Choice PSM diet (containing either cineole or gallic acid). Detoxification products of cineole and gallic acid were examined in urine to determine that different detoxification pathways were utilized in the elimination of each compound. With increasing cineole levels, Possums ate less, had smaller feeding bouts, and had a lower rate of intake, but did not extend their total nightly feeding time. Possums offered the Choice PSM diet, compared with the No-Choice diets, ate more, had larger feeding bouts, and tended to increase their rate of intake. Results from the urinary analysis indicated that gallic acid and cineole were not involved in competing detoxification pathways in Brushtail Possums. There was also a significant sex effect: females ate more overall, ate more per feeding bout, and ate at a higher rate than males. These results indicate that PSMs not only constrain overall intake, but that Possums alter their feeding behavior in response to them. Altered feeding patterns may reduce the negative influence of PSMs on intake.
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application of solid phase microextraction to the quantitative analysis of 1 8 cineole in blood and expired air in a eucalyptus herbivore the Brushtail Possum trichosurus vulpecula
Journal of Chromatography B, 2002Co-Authors: Rebecca Boyle, G. J. Pass, Stuart Mclean, Sue Brandon, Noel W. DaviesAbstract:We have developed two solid-phase microextraction (SPME) methods, coupled with gas chromatography, for quantitatively analysing the major Eucalyptus leaf terpene, 1,8-cineole, in both expired air and blood from the common Brushtail Possum (Trichosurus vulpecula). In-line SPME sampling (5 min at 20 °C room temperature) of excurrent air from an expiratory chamber containing a Possum dosed orally with 1,8-cineole (50 mg/kg) allowed real-time semi-quantitative measurements reflecting 1,8-cineole blood concentrations. Headspace SPME using 50 il whole blood collected from Possums dosed orally with 1,8-cineole (30 mg/kg) resulted in excellent sensitivity (quantitation limit 1 ng/ml) and reproducibility. Blood concentrations ranged between 1 and 1380 ng/ml. Calibration curves were prepared for two concentration ranges (0.05–10 and 10–400 ng/50 il) for the analysis of blood concentrations. Both calibration curves were linear (r2=0.999 and 0.994, respectively) and the equations for the two concentration ranges were consistent.
B. J. Mcleod - One of the best experts on this subject based on the ideXlab platform.
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seasonal changes in rfamide related peptide 3 neurons in the hypothalamus of a seasonally breeding marsupial species the Brushtail Possum trichosurus vulpecula
The Journal of Comparative Neurology, 2013Co-Authors: Anan A Harbid, B. J. Mcleod, Alain Caraty, Greg M AndersonAbstract:RFamide-related peptide-3 (RFRP-3) neurons have been shown to inhibit gonadotropin-releasing hormone (GnRH) neuronal activity and hence reproduction in birds and eutherian mammals. They have also been proposed to have a direct hypophysiotropic effect on pituitary gonadotropin release. We used a new RFRP-3 antibody to characterize the cell body distribution and fiber projections of RFRP-3 neurons in the adult female Brushtail Possum brain. RFRP-3-immunoreactive cell bodies were found scattered within the dorsomedial hypothalamus and the dorsomedial half of the ventromedial hypothalamus, while GnRH neurons were observed scattered rostrocaudally along the lateral septum, rostral to the medial septum. There was a significant 2-fold increase in the RFRP-3 cell body number during the nonbreeding season (summer) compared to the breeding season (winter). Immunoreactive RFRP-3 fibers were distributed throughout the thalamus, preoptic area, and hypothalamus. Very few fibers were observed in the median eminence, especially in the external zone. Intraperitoneal injection of the retrograde tracer Fluoro-Gold resulted in the labeling of 40% of hypophysiotropic tuberoinfundibular dopaminergic (tyrosine hydroxylase-positive) neurons; however, <10% of zona incerta dopaminergic neurons (which are not hypophysiotropic) or RFRP-3 neurons were labeled with this tracer. These observations suggest that RFRP-3 exhibits a seasonal fluctuation in cell numbers, as seen in sheep and birds, which is consistent with an increased inhibitory tone during the nonbreeding season. The lack of RFRP-3 fibers in the median eminence and of Fluoro-Gold uptake from the periphery imply that the actions of this peptide occur primarily centrally rather than at the anterior pituitary gland. J. Comp. Neurol. 521: 3030–3041, 2013. © 2013 Wiley Periodicals, Inc.
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seasonal changes in morphology and steroid receptor expression in the prostate of the Brushtail Possum trichosurus vulpecula an animal model for the study of prostate growth
Reproduction Fertility and Development, 2011Co-Authors: Helen Martyn, Jo W Fink, B. J. Mcleod, Kamali Pugazhenthi, Maree Gould, H D NicholsonAbstract:The prostate of the Brushtail Possum undergoes growth and regression during the year. The present study investigated the morphological changes and expression of androgen and oestrogen receptors during the breeding and non-breeding seasons. Prostate tissue was collected from adult Possums at 2-monthly intervals. The periurethral and outer glandular areas were separated and the volume of stromal, epithelial and luminal tissues measured in each area. Immunohistochemistry was used to investigate cell proliferation with proliferating cell nuclear antigen (PCNA) and to localise androgen receptor (AR) and oestrogen receptors α and β (ERα, ERβ). Seasonal changes in expression of the three receptors were investigated using quantitative PCR and western blot analysis. During the breeding season the volume of stromal tissue in the periurethral area and the luminal volume in the glandular area significantly increased. The change in periurethral volume was associated with increased PCNA-immunopositive cells. While the localisation of AR to the stromal and epithelial cells did not change, there was a significant increase in receptor expression before the main breeding season. ERα and ERβ expression and localisation did not alter during the year. Similarities in receptor expression and localisation suggest that the Possum may be a suitable animal model for the study of human prostate growth.
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release and bioactivity of paca nanoparticles containing d lys6 gnrh for Brushtail Possum fertility control
Journal of Controlled Release, 2011Co-Authors: Alexandra P Kafka, B. J. Mcleod, Thomas Rades, Arlene McdowellAbstract:Abstract Poly(ethylcyanoacrylate) (PECA) nanoparticles containing the chemical sterilitant D-Lys 6 -GnRH were prepared by an in situ interfacial polymerization technique. Their potential as a peroral delivery system for biocontrol of the Brushtail Possum, a major pest species in New Zealand, was evaluated. Peptide release from resulting particles was studied in vitro in artificial gastric juice (AGJ), simulated intestinal fluids (SIF) and Brushtail Possum plasma. The nanoparticles released a small fraction of bioactive over 6 h in AGJ and SIF ( 6 -GnRH. In contrast, 60% of D-Lys 6 -GnRH was released after 1 h in Possum plasma. The nanoparticles were also administered in vivo into the caecum of Brushtail Possums. A significant biological response, measured as an increase in plasma luteinizing hormone (LH), was evident 10 min after administration. This demonstrates not only that PECA nanoparticles were able to facilitate the uptake of D-Lys 6 -GnRH from the caecum into systemic circulation but also that sufficient bioactive peptide reached the pituitary to exert a significant LH response following GnRH receptor mediated endocytosis. Hence, it can be concluded that PECA nanoparticles comprise a promising formulation strategy for the peroral delivery of the chemical sterilitant D-Lys 6 -GnRH to the Brushtail Possum in New Zealand.
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physiology and pharmacology of the Brushtail Possum gastrointestinal tract relationship to the human gastrointestinal tract
Advanced Drug Delivery Reviews, 2007Co-Authors: Arlene Mcdowell, B. J. McleodAbstract:Oral formulations are typically based on studies from eutherian animal models. This review introduces information relating to oral formulations for a marsupial species, the Australian Brushtail Possum (Trichosurus vulpecula) that has arisen from research into new methods for controlling this species - a major vertebrate pest in New Zealand. Morphologically, the gastrointestinal tract of the Brushtail Possum is similar to that of hindgut fermenting eutherian species, but there are some striking differences in function. Limited data suggests that the pharmacokinetics and bioavailability of administered drugs are similar to that in eutherian species, but there is some evidence that Possums may have specific mechanisms for handling the intake of plant toxins and xenobiotics. The development of oral formulations for a free-ranging pest species presents several challenges above those encountered in the development of therapeutic formulations for humans and domestic animals. Use of a marsupial animal model may lead to new strategies for oral formulations in humans.
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gastrointestinal transit in the common Brushtail Possum measured by gamma scintigraphy
International Journal of Pharmaceutics, 2005Co-Authors: Arlene Mcdowell, B. J. Mcleod, J Nicoll, Ian G Tucker, N M DaviesAbstract:This paper reports an example of the application of pharmaceutical technology to wildlife management, specifically the design of an oral delivery system for the common Brushtail Possum in New Zealand. Designing an oral delivery system requires a knowledge of the time taken for particulates to reach target sites within the gastrointestinal tract (GIT). The transit time for fluid and indigestible particles of two different size ranges was determined in the common Brushtail Possum (Trichosurus vulpecula). Technetium-labelled (99mTc) anion exchange resin particles (75-125 or 500-700 microm diameter) or solution (99mTc-labelled diethylenetriamine pentaacetic acid, 99mTc-DTPA) was administered orally. At predetermined times after dosing (3, 6, 12, 24 or 32 h), the distribution of radioactivity throughout excised gastrointestinal tracts was determined by gamma scintigraphy. The transit profile was similar for the three formulations investigated. Unlike other closely related hindgut fermenting marsupials, there was no evidence to support the presence of a colonic separating mechanism in the common Brushtail Possum. Gastrointestinal transit was independent of body mass, gender and time of day that the dose is given. To target the hindgut for oral delivery of protein and peptide biocontrol agents, the formulation would need to protect the bioactive for approximately 12 h prior to release.
Rebecca Boyle - One of the best experts on this subject based on the ideXlab platform.
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Pharmacokinetics of 1,8-cineole, a dietary toxin, in the Brushtail Possum (Trichosurus vulpecula): significance for feeding.
Xenobiotica, 2007Co-Authors: Stuart Mclean, Rebecca Boyle, Sue Brandon, Noel W. Davies, J. S. SorensenAbstract:Cineole (cineole) is a Eucalyptus leaf toxin that defends against predation by herbivores such as the Brushtail Possum (Trichosurus vulpecula). The aim of the current study was to characterize the pharmacokinetics of cineole in the Possum to improve understanding about how Possums can avoid cineole toxicity when eating a Eucalyptus diet. Nine male Possums were trapped in the wild and acclimated to captivity; a subcutaneous port was then implanted for venous blood sampling. Cineole was administered intravenously (10 and 15 mg kg -1 ) via a lateral tail vein and orally (30, 100 and 300 mg kg -1 ) by gavage, and blood concentrations of cineole and its metabolites were determined by gas chromatography. Cineole had a large terminal volume of distribution (Vz ¼ 27 l kg -1 ) and a high clearance (43 ml min -1 kg -1 ), equal to hepatic blood flow. The terminal half-life was approximately 7 h. Oral bioavailability was low (F ¼ 0.05) after low doses, but increased tenfold with dose, probably due to saturable first-pass metabolism. These findings indicate that when Possums feed on a cineole diet, they eat until the cineole consumed is sufficient to saturate pre-systemic metabolism, leading to a rapid rise in bioavailability and cineole blood levels, and a cessation of the feeding bout. This is the first report on the pharmacokinetics of a dietary toxin in a wild herbivore, and provides insights into the interactions between the blood concentration of a plant secondary metabolite and the browsing behaviour of a herbivore.
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Constraint of feeding by chronic ingestion of 1,8-cineole in the Brushtail Possum (Trichosurus vulpecula).
Journal of Chemical Ecology, 2004Co-Authors: Rebecca Boyle, Stuart McleanAbstract:Eucalyptus leaf-eating marsupials such as the Brushtail Possum (Trichosurus vulpecula) ingest large amounts of terpenes, especially 1,8-cineole (cineole)—the major component of many eucalyptus oils. Brushtail Possums were acclimated to a non-Eucalyptus diet with increasing concentrations of cineole (0.5–4.0% wet weight) added over 18 d. We measured food and cineole consumption and urinary metabolites of cineole. Food intake decreased with cineole content, indicating that it was constrained by the maximum tolerable intake of cineole that was 3.8 ± 0.2 g kg−1 or 5.2 ± 0.3 g kg−0.75 (mean ± SE, N = 6). The pattern of metabolites was similar at all cineole intakes (56% hydroxycineolic acids, 27% cineolic acids, 13% hydroxycineoles, and 4% dihydroxycineoles). In another experiment, Possums maintained on artificial diet were abruptly presented with 4% cineole for 5 d. Food intake fell by 45 ± 6% (mean ± SE, N = 6) and mean cineole intake was 2.9 ± 0.3 g kg−1. There was evidence of induction of secondary oxidative pathways, as hydroxycineoles were the major metabolites (48% total) on the first day, but rapidly dropped to 15% on subsequent days as the acid metabolites increased. These findings indicate that ingestion of cineole is not constrained by selective saturation of individual enzymes involved in its multiple pathways of oxidation, but rather the total detoxification capacity appears to limit feeding on a cineole diet.
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effects of two plant secondary metabolites cineole and gallic acid on nightly feeding patterns of the common Brushtail Possum
Journal of Chemical Ecology, 2003Co-Authors: Natasha L. Wiggins, Stuart Mclean, Clare Mcarthur, Rebecca BoyleAbstract:We investigated effects of two plant secondary metabolites (PSMs), cineole and gallic acid, on the nightly feeding behavior of the common Brushtail Possum (Trichosurus vulpecula), a generalist folivore. We tested whether Possums altered their feeding behavior in response to increasing levels of cineole, a dietary terpene. Possums were fed artificial diets containing three levels of cineole; zero (basal diet), medium (6.8% of total dry matter, DM), and high (15.3% DM). In another experiment, we introduced gallic acid, a dietary phenolic, into the diets. Possums were offered a Choice PSM diet (cineole and gallic acid diets simultaneously) or a No-Choice PSM diet (containing either cineole or gallic acid). Detoxification products of cineole and gallic acid were examined in urine to determine that different detoxification pathways were utilized in the elimination of each compound. With increasing cineole levels, Possums ate less, had smaller feeding bouts, and had a lower rate of intake, but did not extend their total nightly feeding time. Possums offered the Choice PSM diet, compared with the No-Choice diets, ate more, had larger feeding bouts, and tended to increase their rate of intake. Results from the urinary analysis indicated that gallic acid and cineole were not involved in competing detoxification pathways in Brushtail Possums. There was also a significant sex effect: females ate more overall, ate more per feeding bout, and ate at a higher rate than males. These results indicate that PSMs not only constrain overall intake, but that Possums alter their feeding behavior in response to them. Altered feeding patterns may reduce the negative influence of PSMs on intake.
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application of solid phase microextraction to the quantitative analysis of 1 8 cineole in blood and expired air in a eucalyptus herbivore the Brushtail Possum trichosurus vulpecula
Journal of Chromatography B, 2002Co-Authors: Rebecca Boyle, G. J. Pass, Stuart Mclean, Sue Brandon, Noel W. DaviesAbstract:We have developed two solid-phase microextraction (SPME) methods, coupled with gas chromatography, for quantitatively analysing the major Eucalyptus leaf terpene, 1,8-cineole, in both expired air and blood from the common Brushtail Possum (Trichosurus vulpecula). In-line SPME sampling (5 min at 20 °C room temperature) of excurrent air from an expiratory chamber containing a Possum dosed orally with 1,8-cineole (50 mg/kg) allowed real-time semi-quantitative measurements reflecting 1,8-cineole blood concentrations. Headspace SPME using 50 il whole blood collected from Possums dosed orally with 1,8-cineole (30 mg/kg) resulted in excellent sensitivity (quantitation limit 1 ng/ml) and reproducibility. Blood concentrations ranged between 1 and 1380 ng/ml. Calibration curves were prepared for two concentration ranges (0.05–10 and 10–400 ng/50 il) for the analysis of blood concentrations. Both calibration curves were linear (r2=0.999 and 0.994, respectively) and the equations for the two concentration ranges were consistent.
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Biotransformation of 1,8-cineole in the Brushtail Possum (Trichosurus vulpecula).
Xenobiotica, 2000Co-Authors: Rebecca Boyle, Stuart Mclean, Noel W. DaviesAbstract:1. The metabolic fate of 1,8-cineole was investigated in the Brushtail Possum. Six Possums were fed an artificial diet to which 0.5% 1,8-cineole (wet weight) was added for 2 days. Urine and faeces were collected after the second day. A sample of each was extracted into ethyl acetate and analysed for metabolites. Both free and total levels of metabolites were identified by GC-MS and LC-MS and quantified by GC-MS. 2. The pattern of metabolite excretion was very complex in the Brushtail Possum. Nineteen metabolites were found in total. Metabolites were categorized into four groups according to the oxidation they had undergone: hydroxycineoles (n = 3), cineolic acids (n = 2), dihydroxycineoles (n = 3) and hydroxycineolic acids (n = 11). No hydroxycineolic acid metabolites have been previously reported as metabolites of 1,8-cineole. 3. Fractional recovery of the ingested dose (2.4±0.5 g; mean±SD) was 0.44±0.14 (mean±SD) in 24 h. Sixty percent of excreted metabolites were hydroxycineolic acids, the most extensi...
J. C. Rodger - One of the best experts on this subject based on the ideXlab platform.
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Induction of Thumbtack Sperm During Coculture with Oviduct Epithelial Cell Monolayers in a Marsupial, the Brushtail Possum (Trichosurus vulpecula)1
2016Co-Authors: K. S. Sidhu, K E Mate, F. C. Molinia, J. C. RodgerAbstract:A reorientation of the sperm head so that it is perpendicular to the sperm tail (i.e., T-shape or thumbtack) is considered an indicator of sperm capacitation in the Australian marsupial the Brushtail Possum (Trichosurus vulpecula). This study describes a method of oviduct epithelial cell monolayer and sperm cocul-ture in the Brushtail Possum to obtain a high percentage of thumbtack sperm. The oviduct epithelial cell (OEC) monolayers were prepared in vitro from the isthmal and ampullary segments of eCG- and LH-primed Brushtail Possum oviducts. Coculture experiments demonstrated that cauda epididymidal sperm from the Brushtail Possum attached equally to the OEC monolayers derived from the isthmal and ampullary segments of the oviduct. After 2 h of coculture, a large number of sperm attached to OEC monolayers (ampulla, 60.1 6 4.7 % and isthmus, 63.1 6 5.7%) as well as to controls (tracheal epithelial cell monolayer, 46.
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the immune response and fertility of koalas phascolarctos cinereus immunised with porcine zonae pellucidae or recombinant Brushtail Possum zp3 protein
Journal of Reproductive Immunology, 2009Co-Authors: Anne L Kitchener, K E Mate, Carmen A Mccartney, David J Kay, Bryan Walters, Peter Menkhorst, Janine A Buist, J. C. RodgerAbstract:Abstract To evaluate the potential contraceptive effect of immunisation with zona pellucida antigens, 50 free-ranging koalas were immunised with either porcine zonae pellucidae (PZP), recombinant Brushtail Possum ZP3 (recBP-ZP3) or buffer, in complete Freund's adjuvant. A single booster immunisation in incomplete Freund's adjuvant was administered 3–5 months later. Where possible animals were recaptured, reproductive status was assessed and blood was collected at 1–3-month intervals for the next 33 months. Forty-three koalas were recaptured at least three times allowing reliable assessments of their fertility. Fourteen animals were observed never to have a pouch young. Of the remaining 29 animals the reproductive productivity of PZP treated females was reduced compared with control and recBP-ZP3 treated females, in terms of both total number of young produced, and failure to produce further young in females of proven fertility. One month after the initial immunisation, serum antigen-specific antibody titres were higher in animals immunised with PZP or recBP-ZP3 compared to controls, and reached a plateau by 4 months. Antibody against the relevant immunising antigen was also detected in ovarian follicular fluid, uterine fluid and vaginal secretions. Epitope analysis suggested that immune responses other than antibodies directed against the ZP3 amino acid sequence were responsible for mediating infertility. The results demonstrate that the fertility of female koalas can be compromised by immunisation against zona pellucida antigens. However, unlike in the eastern grey kangaroo and the Brushtail Possum, immunisation with bacterial recombinant Brushtail Possum ZP3 did not compromise fertility in the koala.
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immunocontraception of eastern grey kangaroos macropus giganteus with recombinant Brushtail Possum trichosurus vulpecula zp3 protein
Journal of Reproductive Immunology, 2009Co-Authors: Anne L Kitchener, K E Mate, Carmen A Mccartney, Amanda Harman, David J Kay, J. C. RodgerAbstract:This study examined the potential of a recombinant marsupial zona pellucida 3 protein as a contraceptive vaccine for the Eastern Grey kangaroo, a marsupial that is locally overabundant in several regions of eastern Australia. First, a pilot study using porcine zona pellucidae (PZP) demonstrated that ZP proteins, primarily the ZP3 component of PZP, are highly immunogenic in the grey kangaroo and produce a long-lasting humoral response to a single immunisation, as found in other marsupials. Immunisation with 300 μg of a non-glycosylated recombinant Brushtail Possum ZP3 (recBP-ZP3) protein in complete Freund's adjuvant produced a similar, significant and sustained antibody response, and none of the immunised kangaroos (n = 7) produced offspring during the following breeding season compared with four out of the six control animals. An epitope analysis of the B-cell response to recBP-ZP3 using a Brushtail Possum ZP3 identified numerous B-cell epitope regions clustered around the N- and C-terminal regions of the protein. Two regions of interest for further fertility vaccine development based on their immunogenicity and fertility trials and functional studies in other species were found to be immunogenic. These results suggest that immunocontraception based on targeting the ZP3 protein within the zona pellucida may be an effective strategy for fertility reduction in Eastern Grey kangaroos.
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a flow cytometric assay for global estimation of tyrosine phosphorylation associated with capacitation of spermatozoa from two marsupial species the tammar wallaby macropus eugenii and the Brushtail Possum trichosurus vulpecula
Reproduction, 2004Co-Authors: Kuldip S Sidhu, K E Mate, T Gunasekera, D Veal, Louise Hetherington, Mark A Baker, R J Aitken, J. C. RodgerAbstract:The phosphorylation of tyrosine residues in cellular proteins is a major signal transduction event during sperm capacitation. In this study protein phosphorylation was monitored using a fluorescein isothiocyanate (FITC)-labeled antiphosphotyrosine monoclonal antibody and a flow cytometric procedure optimized for sperm. Using this technique, the correlation between tyrosine phosphorylation and sperm capacitation was examined in two marsupial species, the Brushtail Possum and the tammar wallaby and compared with that of ram spermatozoa. The levels of tyrosine phosphorylation in sperm from all three species were increased by the addition of cyclic AMP (cAMP) and vandate, a phosphotyrosine phosphatase inhibitor and were decreased by the addition of the phosphotyrosine kinase inhibitor, staurosporine. Oviductal conditioned media (CM) induced a progressive increase in tyrosine phosphorylation in both marsupial species and also induced morphological transition from a streamlined to a 'T'-shape configuration in Brushtail Possum spermatozoa but not in tammar wallaby spermatozoa. Transition to the 'T'-shape orientation associated with capacitation in marsupial spermatozoa was observed by 2 h of incubation in both species when tyrosine phosphorylation was increased by higher levels of cAMP i.e. 5 mM dibutyryl cAMP plus 3 mM pentoxyphylline. Thus the tyrosine phosphorylation trigger with CM may differ in these two marsupial species. Ram sperm tyrosine phosphorylation could be increased by addition of lower levels of cAMP (1 mM). These results support the finding that tyrosine phosphorylation is associated with sperm capacitation in marsupials. Similar results were obtained by using SDS PAGE/Western blot analysis of tyrosine phosphorylation in the Brushtail Possum spermatozoa. The specificity, efficiency and sensitivity of the procedure described here make it applicable for routine assessment of capacitation in large numbers of samples and in other species.