efficacy of oral bcg vaccination in protecting free-ranging cattle from natural infection by mycobacterium bovis.vaccination of cattle against bovine tuberculosis could be a valuable control strategy, particularly in countries faced with intractable ongoing infection from a disease reservoir in wildlife. a field vaccination trial was undertaken in new zealand. the trial included 1286 effectively free-ranging cattle stocked at low densities in a remote 7600ha area, with 55% of them vaccinated using mycobacterium bovis bcg (danish strain 1311). vaccine was administered orally in all but 34 cases (where it wa ...201728888636
camp-dependent secretagogues stimulate the nahco3cotransporter in the villous epithelium of the brushtail possum, trichosurus the ileum of the brushtail possum, trichosurus vulpecula, fluid secretion appears to be driven by electrogenic hco3-secretion. consistent with this, the cystic fibrosis transmembrane conductance regulator is expressed in the apical membrane of the ileal epithelial cells and the pancreatic or secretory variant of the nahco3cotransporter in the basolateral membrane. this suggests that in the possum ileum, electrogenic hco3-secretion is driven by basolateral nahco3cotransporter (nbc) activity. t ...201728247055
how herbivore browsing strategy affects whole-plant photosynthetic capacity.if a browse damage index indicates that a tree has been 50% browsed by herbivores, does this mean half the leaves are entirely eaten or are all the leaves half eaten? were the affected leaves old or young? large or small? in sunshine or shade? understanding what effect browsing will have on the photosynthetic capacity and the plant's survival ability clearly requires a greater understanding of browsing strategy across the canopy than can be given by a single index value. we developed stochastic ...201728194619
refining operational practice for controlling introduced european rabbits on agricultural lands in new zealand.european rabbits (oryctolagus cuniculus) pose a major threat to agricultural production and conservation values in several countries. in new zealand, population control via poisoning is a frontline method for limiting rabbit damage, with large areas commonly treated using the metabolic toxin sodium fluoroacetate ('1080') delivered in bait via aerial dispersal. however, this method is expensive and the high application rates of the active ingredient cause public antipathy towards it. to guide red ...201627341209
the use of polyethylene glycol in mammalian herbivore diet studies: what are we measuring?polyethylene glycol (peg) has been used to study the intake and digestion of tannin-rich plants by mammalian herbivores because it preferentially binds to tannins. however, it is not clear whether the responses of herbivores to dietary peg is due to increased protein availability from the release of tannin-bound protein, amelioration of tannin effects, or whether peg also may bind to other compounds and change their activity in the gut. we used three native new zealand tree species to measure th ...201627256074
foliar nutritional quality explains patchy browsing damage caused by an invasive mammal.introduced herbivores frequently inflict significant, yet patchy damage on native ecosystems through selective browsing. however, there are few instances where the underlying cause of this patchy damage has been revealed. we aimed to determine if the nutritional quality of foliage could predict the browsing preferences of an invasive mammalian herbivore, the common brushtail possum (trichosurus vulpecula), in a temperate forest in new zealand. we quantified the spatial and temporal variation in ...201627171381
incorporating field studies into species distribution and climate change modelling: a case study of the koomal trichosurus vulpecula hypoleucus (phalangeridae).species distribution models (sdms) are an effective way of predicting the potential distribution of species and their response to environmental change. most sdms apply presence data to a relatively generic set of predictive variables such as climate. however, this weakens the modelling process by overlooking the responses to more cryptic predictive variables. in this paper we demonstrate a means by which data gathered from an intensive animal trapping study can be used to enhance sdms by combini ...201627104611
species- and site-specific impacts of an invasive herbivore on tree survival in mixed forests.invasive herbivores are often managed to limit their negative impact on plant populations, but herbivore density - plant damage relationships are notoriously spatially and temporally variable. site and species characteristics (both plant and herbivore) must be considered when assessing the potential for herbivore damage, making it difficult to set thresholds for efficient management. using the invasive brushtail possum trichosurus vulpecula in new zealand as a case study, we parameterized a gene ...201627066221
demonstration of the scalar property of timing with possums (trichosurus vulpecula).many diverse species have demonstrated interval timing, the ability to respond appropriately to time in the range of seconds to minutes, suggesting that an ability to time is adaptive. the peak procedure is a common method of studying interval time perception. in the peak procedure, animals experience a mix of fixed-interval (fi) and extinction (ext) trials. on ext trials, responding typically increases to a peak at the time the fi schedule would normally deliver reinforcers before decreasing. r ...201626974180
the aetiology of wobbly possum disease: reproduction of the disease with purified nidovirus.the objective of this study was to investigate a role of a recently discovered marsupial nidovirus in the development of a neurological disease, termed wobbly possum disease (wpd), in the australian brushtail possum (trichosurus vulpecula). four possums received 1 ml of a standard inoculum that had been prepared from tissues of wpd-affected possums, 4 possums received 1.8 ml (1 × 10(6) tcid50) of a cell lysate from inoculated cultures, and 4 possums received 1 ml (× 10(7) tcid50) of a purified w ...201626874014
aerial prefeeding followed by ground based toxic baiting for more efficient and acceptable poisoning of invasive small mammalian pests.introduced brushtail possums (trichosurus vulpecula) and rat species (rattus spp.) are major vertebrate pests in new zealand, with impacts on conservation and agriculture being managed largely through poisoning operations. aerial distribution of baits containing sodium fluoroacetate (1080) has been refined to maximise cost effectiveness and minimise environmental impact, but this method is strongly opposed by some as it is perceived as being indiscriminate. although ground based control enables ...201526218095
cost-effective large-scale occupancy-abundance monitoring of invasive brushtail possums (trichosurus vulpecula) on new zealand's public conservation land.there is interest in large-scale and unbiased monitoring of biodiversity status and trend, but there are few published examples of such monitoring being implemented. the new zealand department of conservation is implementing a monitoring program that involves sampling selected biota at the vertices of an 8-km grid superimposed over the 8.6 million hectares of public conservation land that it manages. the introduced brushtail possum (trichosurus vulpecula) is a major threat to some biota and is o ...201526029890
primary possum macrophage cultures support the growth of a nidovirus associated with wobbly possum disease.the objective of the study was to establish a system for isolation of a recently described, thus far uncultured, marsupial nidovirus associated with a neurological disease of possums, termed wobbly possum disease (wpd). primary cultures of possum macrophages were established from livers of adult australian brushtail possums (trichosurus vulpecula). high viral copy numbers (up to 6.9×10(8)/ml of cell lysate) were detected in infected cell culture lysates from up to the 5th passage of the virus, i ...201526028426
from leaf metabolome to in vivo testing: identifying antifeedant compounds for ecological studies of marsupial diets.identifying specific plant secondary metabolites that influence feeding behavior can be challenging, but a solid understanding of animal preferences can guide efforts. common brushtail possums (trichosurus vulpecula) predominantly eat eucalyptus species belonging to the subgenus symphyomyrtus, and avoid eating those belonging to the monocalyptus subgenus (also called subgenus eucalyptus). using an unbiased (1)h nmr metabolomics approach, a previous study identified unsubstituted b ring flavanone ...201525994224
effect of stimulus and response separation in a matching-to-sample task in the brushtail possum (trichosurus vulpecula).this study seeks to investigate the impact of changing the proximity of stimulus and response manipulanda on matching-to-sample performance in possums. possums were presented with five rows of blue and yellow stimuli arranged vertically 25mm apart above response levers. generally, peak performance occurred at the distance from the lever currently being trained. performance generalized to distances close to the currently trained distance and decreased in accuracy at distances further from the tra ...201525979605
triacylglycerol estolides, a new class of mammalian lipids, in the paracloacal gland of the brushtail possum (trichosurus vulpecula).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 + nh4](+) ions s ...201525916239
male-biased predation and its effect on paternity skew and life history in a population of common brushtail possums (trichosurus vulpecula).differences in predation risk may exert strong selective pressures on life history strategies of populations. we investigated the potential for predation to shape male mating strategies in an arboreal folivore, the common brushtail possum (trichosurus vulpecula kerr). we predicted that possums in a tropical population exposed to high natural levels of predation would grow faster and reproduce earlier compared to those in temperate populations with lower predation. we trapped a population of poss ...201425372294
personality affects the foraging response of a mammalian herbivore to the dual costs of food and fear.predators attack and plants defend, so herbivores face the dilemma of how to eat enough without being eaten. but do differences in the personality of herbivores affect the foraging choices of individuals? we explored the ecological impact of personality in a generalist herbivore, the brushtail possum (trichosurus vulpecula). after quantifying personality traits in wild individuals brought temporarily into captivity, we tested how these traits altered foraging by individuals when free-ranging in ...201525294220
variations in epithelial na(+) transport and epithelial sodium channel localisation in the vaginal cul-de-sac of the brushtail possum, trichosurus vulpecula, during the oestrous cycle.the fluid in the vaginal cul-de-sac of the brushtail possum, trichosurus vulpecula, is copious at ovulation when it may be involved in sperm transport or maturation, but is rapidly reabsorbed following ovulation. we have used the ussing short-circuit current (isc) technique and measurements of transcript and protein expression of the epithelial na(+) channel (enac) to determine if variations in electrogenic na(+) transport are associated with this fluid absorption. spontaneous isc (<20µacm(-2) d ...201625056576
erratum to: chemical characterization of milk oligosaccharides of the common brushtail possum (trichosurus vulpecula). 201425015760
assessing stability of body weight in the brushtail possum (trichosurus vulpecula).when conducting controlled laboratory studies with non-traditional laboratory animals it is important that methods for determining body weight stability are reliable. this helps ensure the health and welfare of animals when they are maintained during periods of free feeding or food restriction. this study compared different methods for determining body weight stability in six common brushtail possums (trichosurus vulpecula) maintained on a free-feeding diet under laboratory conditions. a criteri ...201524958547
determination of villous rigidity in the distal ileum of the possum (trichosurus vulpecula).we investigated the passive mechanical properties of villi in ex vivo preparations of sections of the wall of the distal ileum from the brushtail possum (trichosurus vulpecula) by using a flow cell to impose physiological and supra-physiological levels of shear stress on the tips of villi. we directly determined the stress applied from the magnitude of the local velocities in the stress inducing flow and additionally mapped the patterns of flow around isolated villi by tracking the trajectories ...201424956476
creating new evolutionary pathways through bioinvasion: the population genetics of brushtail possums in new zealand.rapid increases in global trade and human movement have created novel mixtures of organisms bringing with them the potential to rapidly accelerate the evolution of new forms. the common brushtail possum (trichosurus vulpecula), introduced into new zealand from australia in the 19th century, is one such species having been sourced from multiple populations in its native range. here, we combine microsatellite dna- and gis-based spatial data to show that t. vulpecula originating from at least two d ...201424943509
photoreceptor topography and spectral sensitivity in the common brushtail possum (trichosurus vulpecula).marsupials are believed to be the only non-primate mammals with both trichromatic and dichromatic color vision. the diversity of color vision systems present in marsupials remains mostly unexplored. marsupials occupy a diverse range of habitats, which may have led to considerable variation in the presence, density, distribution, and spectral sensitivity of retinal photoreceptors. in this study we analyzed the distribution of photoreceptors in the common brushtail possum (trichosurus vulpecula). ...201424737644
quantifying the direct transfer costs of common brushtail possum dispersal using least-cost modelling: a combined cost-surface and accumulated-cost dispersal kernel approach.dispersal costs need to be quantified from empirical data and incorporated into dispersal models to improve our understanding of the dispersal process. we are interested in quantifying how landscape features affect the immediately incurred direct costs associated with the transfer of an organism from one location to another. we propose that least-cost modelling is one method that can be used to quantify direct transfer costs. by representing the landscape as a cost-surface, which describes the c ...201424505467
roles of the volatile terpene, 1,8-cineole, in plant-herbivore interactions: a foraging odor cue as well as a toxin?olfaction is an important sense for many animals, yet its role in foraging by herbivores is poorly known. many plants contain volatile compounds, such as terpenes, that are not only volatile but can be toxic if ingested. volatile terpenes can be used by herbivores to assess leaf quality, but there is little evidence for whether they are also used as a searching cue. we applied the giving-up density (gud) framework to examine fine-scale foraging by two free-ranging mammalian herbivores, the brush ...201424122179
seed dispersal of the australian cycad macrozamia miquelii (zamiaceae): are cycads megafauna-dispersed "grove forming" plants? 201323711908
effects of temporal resolution on an inferential model of animal movement.recently, there has been much interest in describing the behaviour of animals by fitting various movement models to tracking data. despite this interest, little is known about how the temporal 'grain' of movement trajectories affects the outputs of such models, and how behaviours classified at one timescale may differ from those classified at other scales. here, we present a study in which random-walk state-space models were fit both to nightly geospatial lifelines of common brushtail possums (t ...201323671558
whole-body protein turnover reveals the cost of detoxification of secondary metabolites in a vertebrate browser.the detoxification limitation hypothesis predicts that the metabolism and biotransformation of plant secondary metabolites (psms) elicit a cost to herbivores. there have been many attempts to estimate these costs to mammalian herbivores in terms of energy, but this ignores what may be a more important cost-increases in protein turnover and concomitant losses of amino acids. we measured the effect of varying dietary protein concentrations on the ingestion of two psms (1,8 cineole-a monoterpene, a ...201323640139
development of a real-time reverse transcription pcr assay for detection of a novel nidovirus associated with a neurological disease of the australian brushtail possum (trichosurus vulpecula).to develop a quantitative reverse transcription pcr (rt-qpcr) assay for detection of the putative wobbly possum disease (wpd) virus and to apply this test to investigate the viral load in archival tissues from past wpd transmission studies.201323600460
seasonal changes in rfamide-related peptide-3 neurons in the hypothalamus of a seasonally breeding marsupial species, the brushtail possum (trichosurus vulpecula).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 wi ...201323504980
predicting summer site occupancy for an invasive species, the common brushtail possum (trichosurus vulpecula), in an urban environment.invasive species are often favoured in fragmented, highly-modified, human-dominated landscapes such as urban areas. because successful invasive urban adapters can occupy habitat that is quite different from that in their original range, effective management programmes for invasive species in urban areas require an understanding of distribution, habitat and resource requirements at a local scale that is tailored to the fine-scale heterogeneity typical of urban landscapes. the common brushtail pos ...201323469277
a faecal index of diet quality that predicts reproductive success in a marsupial folivore.estimating the nutritional value of a herbivore's diet is difficult because it requires knowing what the animal eats, the relative quality of each component and how these components interact in relation to animal physiology. current methods are cumbersome and rely on many assumptions that are hard to evaluate. we describe a new method for estimating relative diet quality directly from faeces that avoids the problems inherent in other methods. we combine this method with near infrared reflectance ...201323443356
thresholds in plant-herbivore interactions: predicting plant mortality due to herbivore browse damage.patterns of herbivore browse at small scales, such as the rate of leaf consumption or plant preferences, drive the impact of herbivores on whole-plant processes, such as growth or survival, and subsequent changes in plant population structure. however, herbivore impacts are often non-linear, highly variable and context-dependent. understanding the effect of herbivores on plant populations therefore requires a detailed understanding of the relationships that drive small-scale processes, and how t ...201323188054
influences of plant toxins and their spatial distribution on foraging by the common brushtail possum, a generalist mammalian herbivore.generalist herbivores forage on a variety of plant species, allowing them to gain nutrients while limiting ingestion of harmful toxins. as the capacity to mix diets appears important for maximizing intake, the spatial scale in heterogeneity of food resources should influence the foraging behavior of herbivores. our aim was to identify how the feeding strategy of a generalist mammalian herbivore, the common brushtail possum, responds to foods within a spatially defined environment. we evaluated f ...201223179099
scent chemicals of the brushtail possum, trichosurus vulpecula.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. ...201222976591
assessing acute effects of trapping, handling, and tagging on the behavior of wildlife using gps telemetry: a case study of the common brushtail possum.trapping, handling, and deployment of tracking devices (tagging) are essential aspects of many research and conservation studies of wildlife. however, often these activities place nonhuman animals under considerable physical or psychological distress, which disrupts normal patterns of behavior and may ultimately result in deleterious effects on animal welfare and the validity of research results. thus, knowledge of how trapping, handling, and tagging alter the behavior of research animals is ess ...201222742197
development of the spinal cord and peripheral nervous system in platypus (ornithorhynchus anatinus) and short-beaked echidna (tachyglossus aculeatus).the modern monotremes (platypus and echidnas) are characterized by development of their young in a leathery egg that is laid into a nest or abdominal pouch. at hatching, the young are externally immature, with forelimbs capable of digitopalmar prehension, but hindlimbs little advanced beyond limb buds. the embryological collections at the museum für naturkunde in berlin were used to examine the development of the spinal cord and early peripheral nervous system in developing monotremes and to cor ...201222401666
cftr is restricted to a small population of high expresser cells that provide a forskolin-sensitive transepithelial cl- conductance in the proximal colon of the possum, trichosurus vulpecula.the cystic fibrosis transmembrane conductance regulator (cftr) is central to anion secretion in both the possum and eutherian small intestine. here, we investigated its role in the possum proximal colon, which has novel transport properties compared with the eutherian proximal colon. despite considerable cftr expression, high doses of the cftr activator forskolin (ec(50)≈10 μmol l(-1)) were required for a modest, cftr-dependent increase in short-circuit current (i(sc)) in the proximal colon. pre ...201222399668
identification of a novel nidovirus associated with a neurological disease of the australian brushtail possum (trichosurus vulpecula).a novel, fatal neurological disease of the australian brushtail possum (trichosurus vulpecula) was first identified in 1995 in a research facility and subsequently in free-living possums in new zealand and termed wobbly possum disease (wpd). the results of previous transmission studies suggested that the aetiological agent of wpd is most likely a virus. however, the identity of the presumed viral agent had not been elucidated. in the current report, we describe identification of a novel virus fr ...201222153843
behavior-based assessment of the auditory abilities of brushtail possums.brushtail possums (trichosurus vulpecula) were trained to press a right lever when a tone was presented (a tone-on trial) and a left lever when a tone was not presented (a tone-off trial) to gain access to food. during training the tone was set at 80 db(a), with a frequency of 0.88 kh for 3 possums and of 4 kh for the other 2. once accuracy was over 90% correct across five consecutive sessions, a test session was conducted where the intensity of the tone was reduced by 8 db(a) over blocks of 20 ...201121765549
the distribution and expression of cftr restricts electrogenic anion secretion to the ileum of the brushtail possum, trichosurus eutherian mammals, fluid secretion is essential for intestinal function. this is driven by electrogenic cl(-) secretion, which involves a nak2cl cotransporter (nkcc1) in the enterocyte basolateral membrane and the cystic fibrosis transmembrane conductance regulator (cftr) in the apical membrane. however, in the possum ileum, nkcc1 expression is low and secretagogues stimulate electrogenic hco(3)(-) secretion driven by a basolateral nahco(3) cotransporter (pnbce1). here we investigated whether ...201121562182
vertebrate pesticide risk assessment by indigenous communities in new new zealand, the vertebrate pesticide sodium fluoroacetate (compound 1080) is aerially applied in baits for control of the brush-tailed possum trichosurus vulpecula (kerr, 1792). maori, the indigenous people of new zealand, have raised concerns about 1080 impacts on culturally-important species. here, we outline two steps taken to help maori assess 1080 risk. first, field research was undertaken to determine if naturally-occurring plants utilized by a maori community for food and medicine wou ...201021392320
titrating the cost of plant toxins against predators: determining the tipping point for foraging herbivores.1. foraging herbivores must deal with plant characteristics that inhibit feeding and they must avoid being eaten. principally, toxins limit food intake, while predation risk alters how long animals are prepared to harvest resources. each of these factors strongly affects how herbivores use food patches, and both constraints can pose immediate proximate costs and long-term consequences to fitness. 2. using a generalist mammalian herbivore, the common brushtail possum (trichosurus vulpecula), our ...201121366564
prolactin acts on the hypothalamic-pituitary axis to modulate follicle-stimulating hormone gene expression in the female brushtail possum (trichosurus vulpecula).brushtail possums exhibit a distinct preovulatory pattern of prolactin (prl) secretion suggesting that prl is involved in normal reproductive function. in some mammals, prl is essential for corpus luteum (cl) function and/or modulation of steroidal effects on hypothalamic-pituitary activity. the aim of this study was to test the effects of biologically active recombinant possum prl (recposprl) on both pituitary gland and cl function in possums. to confirm biological activity, administration of r ...201121187096
maternal influence on philopatry and space use by juvenile brushtail possums (trichosurus vulpecula).1.  the causes of juvenile sex-biased philopatry and space use in mammals remain poorly understood, and results of previous research have been conflicting. experimental interventions and manipulations on wild populations are rare, but can play an important role in establishing the factors governing offspring space use. 2.  we experimentally removed mothers of independent juvenile brushtail possums from the maternal home range and examined changes in offspring space use with global positioning sy ...201121155769
energy substrate utilization in the common brushtailed possum (trichosurus vulpecula) using intravenous tolerance tests.the aim of this study was to investigate the energy substrate requirements of the common brushtailed possum (trichosurus vulpecula) using intravenous tolerance tests for glucose, alanine, and propionate in five adult male and female animals under standardized conditions. significant differences (p<0.01) were observed for fasting blood glucose values between males (6.3±0.16 mmol l(-1)) and females (4.8±0.13 mmol l(-1)), and males had a significantly (p<0.001) increased response to glucose. all an ...201120977945
the role of igfs in the regulation of ovarian follicular growth in the brushtail possum (trichosurus vulpecula).igfs are known to be key regulators of ovarian follicular growth in eutherian mammals, but little is known regarding their role in marsupials. to better understand the potential role of igfs in the regulation of follicular growth in marsupials, expression of mrnas encoding igf1, igf2, igf1r, igf-binding protein 2 (igfbp2), igfbp4 and igfbp5 was localized by in situ hybridization in developing ovarian follicles of the brushtail possum. in addition, the effects of igf1 and igf2 on granulosa cell f ...201020522481
acid loads induced by the detoxification of plant secondary metabolites do not limit feeding by common brushtail possums (trichosurus vulpecula).we fed common brushtail possums artificial diets containing a buffer and the plant secondary metabolite (psm), orcinol, to test the hypothesis that organic acids, common products of psm metabolism, limit feeding by common brushtail possums (trichosurus vulpecula). we introduced several diets containing orcinol and a buffer (urinary alkalising agent) over a course of three experiments. a diet containing 2% orcinol (wet matter) caused possums to reduce their food intake immediately, but feeding re ...201019727760
secretagogues stimulate electrogenic hco3- secretion in the ileum of the brushtail possum, trichosurus vulpecula: evidence for the role of a na+/hco3- cotransporter.fluid secretion is essential for intestinal function and, in eutherian mammals, is driven by electrogenic cl(-) transport, which is dependent upon a bumetanide-sensitive, basolateral na(+)/k(+)/2 cl(-) cotransporter, nkcc1. however, ileal secretion in the brushtail possum, a marsupial, involves a fundamentally different process, since nkcc1 expression is low in this tissue and the secretagogue-induced short circuit current (i(sc)) is insensitive to bumetanide. in view of these differences we hav ...200919648410
inter-population differences in the tolerance of a marsupial folivore to plant secondary metabolites.plant secondary metabolites (psms) strongly influence diet selection by mammalian herbivores. concentrations of psms vary within and among plant species, and across landscapes. therefore, local adaptations may cause different populations of herbivores to differ in their ability to tolerate psms. here, we tested the food intake responses of three populations of a marsupial folivore, the common brushtail possum (trichosurus vulpecula kerr), from different latitudes and habitat types, to four types ...200919585152
electrogenic cl(-) secretion does not occur in the ileum of the australian common brushtail possum, trichosurus vulpecula, due to low levels of expression of the nak2cl cotransporter, nkcc1.the colon of the brushtail possum does not have an electrogenic secretory response. given the functional significance of electrogenic cl(-) secretion in the intestine of eutherian mammals, we have investigated the secretory response in the small intestine of this marsupial. in the ussing chamber camp-dependent secretagogues stimulated a sustained increase in ileal short-circuit current (isc), whereas ca(2+)-dependent secretagogues induced a transient increase. both the responses were inhibited b ...200919565248
the effects of plant defensive chemistry on nutrient availability predict reproductive success in a mammal.plants contain a variety of chemical defenses that strongly affect feeding rates in captive mammals, but their effects on the fitness of wild herbivores are largely unknown. this is because the complexity of defensive compounds, and herbivores' counteradaptations to them, make their effects in the wild difficult to measure. we show how tannins interact with protein to produce spatial variation in the nutritional quality of eucalypt foliage, which is related to demography in a wild population of ...200919341141
noninvasive recovery and detection of possum trichosurus vulpecula dna from bitten bait interference devices (waxtags).the brushtail possum is a major agricultural and ecological pest in new zealand. a novel noninvasive dna sampling tool for detecting its presence (waxtags, or wt) was tested. dna was recovered from saliva left on wt, and two lengths (407 bp and 648 bp) of the cytochrome c oxidase i (coi) barcoding region were amplified by polymerase chain reaction (pcr). pcr products were considered (+) when a dna band was clearly visible by electrophoresis. different factors that might affect pcr (+) were inves ...200921564680
gene expression and secretion of lh and fsh in relation to gene expression of gnrh receptors in the brushtail possum (trichosurus vulpecula) demonstrates highly conserved eutherian mammals, the gonadotrophins (lh and fsh) are synthesized and stored in gonadotroph cells under the regulation of multiple mechanisms including gnrh. very little is known about the regulation of gonadotrophin secretion and storage in pituitary glands of marsupials. this study revealed, using quantitative pcr and heterologous ria techniques, that lhb mrna expression levels remained constant over the oestrous cycle, regardless of the presence of a preovulatory lh surge, which is charac ...200918818271
high variability in the mhc class ii da beta chain of the brushtail possum (trichosurus vulpecula).the diversity of class ii major histocompatibility complex (mhc) loci was investigated in the brushtail possum, an important marsupial pest species in new zealand. immunocontraception, a form of fertility control that generates an autoimmune response, is being developed as a population control method for the possum. because the immune response is partly under genetic control, an understanding of immunogenetics in possum will be crucial to the development of immunocontraceptive vaccines. mhc mole ...200818758765
allometry of evaporative water loss in marsupials: implications of the effect of ambient relative humidity on the physiology of brushtail possums (trichosurus vulpecula).to better understand the effects of ambient relative humidity (rh) on physiological variables and the implications of rh-correcting evaporative water loss (ewl) data for marsupials, we examined the effect of rh on ewl, body temperature (tb), metabolic rate (mr) and thermal conductance (c) of the brushtail possum (trichosurus vulpecula), a medium-sized marsupial. correcting ewl data for 27 species of marsupial for water vapour pressure deficit (deltawvp) in the chamber during measurement signific ...200818723532
identification of novel major histocompatibility complex class i sequences in a marsupial, the brushtail possum (trichosurus vulpecula).the major histocompatibility complex (mhc) is an essential part of the vertebrate immune response. mhc genes may be classified as classical, non-classical or non-functional pseudogenes. we have investigated the diversity of class i mhc genes in the brushtail possum, a marsupial native to australia and an introduced pest in new zealand. the mhc of marsupials is poorly characterised compared to eutherian mammal species. comparisons between marsupials and eutherians may enhance understanding of the ...200818636252
novel alleles in classical major histocompatibility complex class ii loci of the brushtail possum (trichosurus vulpecula).we have investigated the diversity of class ii major histocompatibility complex (mhc) loci in the brushtail possum (trichosurus vulpecula), an important marsupial pest species in new zealand. immunocontraceptive vaccines, a method of fertility control that employs the immune system to attack reproductive cells or proteins, are currently being researched as a means of population control for the possum. variation has been observed in the immune response of individual possums to immunocontraceptive ...200818548245
characterization of the hemoglobins of the neonatal brushtailed possum trichosurus vulpecula (kerr): evidence for a highly cooperative, aggregated isoform of hemoglobin.the red blood cells of the neonatal brushtailed possum exhibit unusually strong cooperativity at high levels of oxygen saturation (n=5.4) which appear to arise from a concentration dependent aggregation of one of the neonatal hemoglobin isoforms. red blood cells from neonatal pouched young exhibit a bohr factor of -0.36. stripped hemolysate is sensitive to added 2,3-bisphosphoglycerate (bpg) (apparent binding constant k=35 micromol l(-1)) and atp (k=180 micromol l(-1)), but is largely insensitiv ...200818420437
expression of mrnas encoding oestrogen receptor (er) alpha and erbeta, androgen receptor and progesterone receptor during gonadal and follicular development in the marsupial brushtail possum (trichosurus vulpecula).the objective of the present study was to determine which ovarian cells express mrnas for oestrogen (eralpha and erbeta), androgen (ar) and progesterone (pr) receptors during ovarian and follicular development in the brushtail possum. expression of eralpha and/or erbeta mrna was observed from birth, initially in cells of the blastema, then in the medullary cords from day 20. eralpha was expressed in the oocytes and granulosa cells of secondary and antral follicles. preovulatory follicles did not ...200818402753
development of tolerance to the dietary plant secondary metabolite 1,8-cineole by the brushtail possum (trichosurus vulpecula).the common brushtail possum (trichosurus vulpecula) is a generalist herbivore whose diet includes eucalyptus leaves that are well defended by plant secondary metabolites (psm) such as the terpene 1,8-cineole (cineole). we accustomed possums to a terpene-free diet, then challenged them with the addition of 2% cineole to the diet. initially, there was a 50% reduction in total overnight food consumption associated with a marked decrease in the mass of the major feeding bout. after nine nights, howe ...200818401660
effects of deslorelin implants on reproduction in the common brushtail possum (trichosurus vulpecula).the present study investigated the effects of slow-release implants containing the gonadotrophin-releasing hormone (gnrh) agonist deslorelin on reproduction in the common brushtail possum (trichosurus vulpecula). captive female brushtail possums were assigned to control (placebo implant), low dose (4.7 mg deslorelin) or high dose (9.4 mg deslorelin) groups; males were assigned to control or high dose (9.4 mg deslorelin) groups. the acute effects of deslorelin treatment at the level of the pituit ...200718076822
pharmacokinetics of 1,8-cineole, a dietary toxin, in the brushtail possum (trichosurus vulpecula): significance for feeding.1,8-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 admini ...200717896321
characterization of the hemoglobins of the adult brushtailed possum, trichosurus vulpecula (kerr) reveals non-genetic heterogeneity.the hemoglobins contained within the red blood cells of the adult brushtail possum exhibited cooperative (n=2.6) oxygen binding curves with an associated p50 of 38 mm hg at ph 7.4 and a large bohr effect (-0.60). stripped hemolysate showed a bohr effect of -0.27, and was sensitive to added dpg (k=56 micromol l(-1)), atp (k=130 micromol l(-1)), and chloride ions. four isoforms of hemoglobin were identified using isoelectric focusing. mass spectrometry indicated that all four isoforms most likely ...200717689995
proteomic analysis of whey and casein proteins in early milk from the marsupial trichosurus vulpecula, the common brushtail possum.whey and casein proteins representing the first and second halves of the early lactation phase in the common brushtail possum (trichosurus vulpecula) have been compared by two dimensional gel electrophoresis. nine components of whey were differentially expressed during early lactation, including proteins identified as cathepsin b, clusterin, late lactation protein, lysozyme, ganglioside m2 activator and neutrophil gelatinase-associated lipocalin. a major novel protein, termed very early lactatio ...200720483284
behavioural, biochemical, and pathological responses of possums (trichosurus vulpecula) poisoned with phosphorus investigate the behavioural, biochemical and pathological responses of possums following poisoning with phosphorus paste, in order to assess the implications for the welfare of possums.200717534411
enhancing absorption of fluorescein and lhrh across hindgut epithelia in a marsupial, the common brushtail possum trichosurus vulpecula.we have identified differences in transport properties of intestinal epithelia in the marsupial brushtail possum, compared to eutherian mammals. to determine whether differences in its permeability to hydrophilic compounds also occur, the absorption of sodium fluorescein and luteinizing hormone releasing hormone (lhrh) was assessed in vitro and the ability of chemical enhancers and a metabolic inhibitor to promote their absorption investigated. the apparent permeability of colonic and caecal tis ...200717506515
spatial distribution of defense chemicals and markers and the maintenance of chemical variation.exploring the spatial distribution of variation in plant secondary metabolites is critical for understanding the evolutionary ecology of biochemical diversity in wild organisms. in the present study, concentrations of foliar sideroxylonal, an important and highly heritable defense chemical of eucalyptus melliodora, displayed strong, fine-scale spatial autocorrelation. the spatial patterns observed could promote associational effects on herbivore foraging decisions, which may influence the select ...200717503599
high definition mapping of circular and longitudinal motility in the terminal ileum of the brushtail possum trichosurus vulpecula with watery and viscous perfusates.longitudinal and radial movements during spontaneous contractions of isolated segments of terminal ileum of the brushtail possum, a species of arboreal folivore, were studied using high definition spatiotemporal maps. segments obtained from specimens were continuously perfused with solutions of various apparent viscosities at 3 cm and 5 cm hydrostatic pressure. a series of sustained tetrodotoxin-sensitive peristaltic events occurred during perfusion. the leading edge of each peristaltic event pr ...200717342493
immunogenicity and contraceptive potential of three infertility-relevant zona pellucida 2 epitopes in the marsupial brushtail possum (trichosurus vulpecula).in a previous study, three infertility-relevant epitopes of possum zp2 (pep12 (amino acids 111-125), pep31 (amino acids 301-315), and pep44 (amino acids 431-445)) were identified using sera from possums (trichosurus vulpecula) immunized with recombinant possum zona pellucida 2 (zp2) constructs, and a synthetic peptide library of possum zp2 protein. in this study, the three peptides were conjugated to keyhole limpet hemocyanin and 300 mug of each conjugated peptide were administered subcutaneousl ...200717244744
terminal reproductive effort in a theory predicts that as organisms approach the end of their life, they should increase their reproductive effort (re). however, studies on mammals often find that measures of re do not vary with maternal age. this might be because offspring have some control over energy transfer which may constrain adaptive variation in re by mothers, particularly in eutherian mammals where placental function is primarily controlled by offspring. however, in marsupials, energy transfer is primarily ...200517148185
spatial scale of the patchiness of plant poisons: a critical influence on foraging efficiency.generalist mammalian browsers and folivores feed on a range of chemically different plant species, which may assist them in diluting toxins and diversifying nutrient consumption. the frequency and order in which their diets are mixed are important determinants of intake. as a result, the degree of plant heterogeneity in an environment, and the spatial scale at which this occurs, should directly influence herbivore foraging decisions. we tested whether altering the spatial scale of plants, and th ...200616995624
conflicting demands on detoxification pathways influence how common brushtail possums choose their diets.most herbivores eat more and survive better when they have access to a variety of foods. one explanation involves the detoxification of plant secondary metabolites (psms). by feeding from a variety of plants that contain different classes of psms, animals can use multiple detoxification pathways and presumably consume more food. although popular, this theory is difficult to test because it requires knowledge of the detoxification pathways of each psm in the diet. we established that common brush ...200616937649
plasma concentrations of prolactin in brushtail possums (trichosurus vulpecula) in different physiological states.prolactin (prl) has been implicated in reproduction in many mammalian species and is illustrated by the distinctive patterns of secretion during the breeding season, the oestrous cycle and lactation. the recent development of a homologous ria for measuring the circulating prl concentrations in brushtail possums has facilitated the reliable measurement of prl in plasma during different physiological states in this species for the first time. determination of prl concentrations during lactation in ...200616899563
behavioral responses of a generalist mammalian folivore to the physiological constraints of a chemically defended diet.mammalian herbivores, particularly browsers and folivores, encounter and consume a range of plant chemical defenses [plant secondary metabolites (psms)] on a regular basis. the physiological regulation of psm ingestion and the resulting behavioral responses of mammalian herbivores directly affect their feeding decisions and the subsequent foraging strategies that they adopt. generalist mammalian herbivores are hypothesized to consume a generalized diet because of physiological limitations of the ...200616770709
viscoelastic behaviour aids extrusion from and reabsorption of the liquid phase into the digesta plug: creep rheometry of hindgut digesta in the common brushtail possum trichosurus vulpecula.temporal variation in the rheometric properties of the proximal and distal colonic digesta of an arboreal marsupial folivore, the common brushtail possum, was examined to assess flow behaviour during peristalsis, segmentation and other aspects of intestinal motility. the time-dependent rheometric characteristics on application of a constant shear stress within the physiological range showed an initial elastic and subsequent viscoelastic phase, which fitted burger's model of creep compliance. sim ...200616482429
rapid absorption of dietary 1,8-cineole results in critical blood concentration of cineole and immediate cessation of eating in the common brushtail possum (trichosurus vulpecula).the blood concentration of 1,8-cineole and its metabolites was measured in six male brushtail possums while they voluntarily fed on diets laced with varying concentrations of cineole for 3 d. on the third day, blood samples were collected during and after each bout of feeding for 3 hr. blood cineole was measured by using headspace solid-phase microextraction (spme), while cineole metabolites were measured by liquid-liquid extraction followed by gas chromatography-mass spectroscopy. feeding patte ...200516365704
diet switching in a generalist mammalian folivore: fundamental to maximising intake.generalist mammalian herbivores exploit a diverse diet. a generalised feeding strategy utilises a mixed diet to obtain a range of nutrients and to reduce the detoxication load of similar groups of plant secondary metabolites (psms). there is limited research investigating how mammalian herbivores achieve this dietary mixing in their daily foraging activities. we investigated the patterns of, and behaviours associated with, dietary mixing in a generalist mammalian folivore, the common brushtail p ...200616328546
gastrointestinal transit in the common brushtail possum measured by gamma scintigraphy.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 vulp ...200516112826
establishing and maintaining an operant research facility with brushtail possums (trichosurus vulpecula).the common brushtail possum (trichosurus vulpecula) is a readily accessible marsupial that has been shown to adapt relatively well to captivity. the aim of this paper is to outline the husbandry procedures, experimental equipment, and methodologies used successfully within our possum colony since 1995.200516097359
purification of secretory immunoglobulin a from milk of the brushtail possum (trichosurus vulpecula).to identify and purify secretory immunoglobulin a (siga), a key effecter molecule in mucosal immune responses, from milk of the brushtail possum (trichosurus vulpecula).200116032190
humoral immunity to cholera toxin and ovalbumin in the brushtail possum (trichosurus vulpecula).to compare the humoral immune responses of female possums to ovalbumin (ova) and cholera toxin (ct) administered using different routes and dosage regimes.200116032163
poisoning with 3-nitropropionic acid in possums (trichosurus vulpecula).to evaluate the toxicity, animal behavioural effects and animal welfare implications of 3-nitropropionic acid administration in possums.200016032126
a neurological syndrome in a free-living population of possums (trichosurus vulpecula).to determine the clinical and pathological features of a neurological disease syndrome in a free-living possum population in new zealand and to compare this syndrome with wobbly possum disease.200016032110
metastatic mineralisation in brushtail possums (trichosurus vulpecula) from kawau describe the nature and incidence of metastatic mineralisation in brushtail possums (trichosurus vulpecula) caught on kawau island.199816032050
routine blood values for new zealand brushtail possums (trichosurus vulpecula) at capture. 199816032012
endoparasites of brushtail possums (trichosurus vulpecula) from the south island, new part of a study to assess whether endoparasites could assist in the biological control of brushtail possums in new zealand, we investigated the composition and distribution of possum endoparasites in the south island. possums were collected near five of the original release areas in the south island : banks peninsula, hokitika, nelson, dunedin and invercargill. among the nematodes, those most frequently encountered were trichostrongylus spp., which were present in possums from all five study ...199716032002
internal parasites of possums (trichosurus vulpecula) from kawau island, chatham island and stewart part of a search for pathogens that might be useful agents for biological control of possums, the three largest offshore islands of new zealand that still have possums were surveyed to determine the pathogens present in these isolated populations. brushtail possums from kawau island (n = 158), chatham island (n = 214) and stewart island (n = 194) were examined for internal parasites. possums from kawau island were infected with eimeria spp. (16.7%), bertiella trichosuri (5.2%) and purustrongy ...199716031999
periodic fluid extrusion and models of digesta mixing in the intestine of a herbivore, the common brushtail possum (trichosurus vulpecula).the digesta in four gut compartments (proximal and distal halves of small intestine, caecum, and proximal colon) of a wild hindgut fermenting herbivore, the common brushtail possum (trichosurus vulpecula), were investigated by rheometry and permeametry. digesta from all compartments were highly viscous and exhibited shear-thinning. apparent viscosity was positively related to dry matter content, and increased from proximal small intestine to colon. dynamic rheological measurements showed that in ...200515928916
inheritance of resistance to mammalian herbivores and of plant defensive chemistry in a eucalyptus species.hybridization in plants provides an opportunity to investigate the patterns of inheritance of hybrid resistance to herbivores, and of the plant mechanisms conferring this resistance such as plant secondary metabolites. we investigated how inter-race differences in resistance of eucalyptus globulus to a generalist mammalian herbivore, trichosurus vulpecula, are inherited in their f1 hybrids. we assessed browsing damage of three-year-old trees in a common environment field trial on four hybrid typ ...200515898499
inheritance of resistance to mammalian herbivores and of plant defensive chemistry in an eucalyptus species.hybridization in plants provides an opportunity to investigate the patterns of inheritance of hybrid resistance to herbivores, and of the plant mechanisms conferring this resistance such as plant secondary metabolites. we investigated how inter-race differences in resistance of eucalyptus globulus to a generalist mammalian herbivore, trichosurus vulpecula, are inherited in their fl hybrids. we assessed browsing damage of 3-year-old trees in a common environment field trial on four hybrid types o ...200515856789
mapping of b cell epitopes on the zona pellucida 2 protein of a marsupial, the brushtail possum (trichosurus vulpecula).immunocontraceptive vaccines against zona pellucida (zp) proteins are being developed for brushtail possum (trichosurus vulpecula) management in new zealand. mapping of b cell epitopes on the zp2 protein of possums was undertaken in this study to define the antigenic regions that may be crucial to sperm-egg binding. the amino acid sequence of the full-length possum zp2 protein (712 amino acids) was used to synthesize a complete set of 71 (15-mer) biotinylated peptides with an offset of five amin ...200515685627
effects of nutrient variability on the genetic-based resistance of eucalyptus globulus to a mammalian herbivore and on plant defensive chemistry.plant resistance to herbivores can be influenced not only by the independent effects of plant genotype and environmental variation, but by interactions between the two. the main aim of this study was to assess the effects of environmental variability (nutrient treatment) on the known genetic-based expression of resistance and defensive chemistry of eucalyptus globulus to browsing by the generalist mammalian herbivore trichosurus vulpecula. in a captive feeding trial, we measured intake of seedli ...200515583943
cycle of the seminiferous epithelium in a marsupial species, the brushtail possum (trichosurus vulpecula), and estimation of its duration.we investigated the cycle of the seminiferous epithelium in a marsupial, namely the brushtail possum (trichosurus vulpecula), using semithin sections of seminiferous tubules embedded in spurr's resin. using 14 steps of spermatid development as markers, we were able to class tubular cross-sections into 10 well-defined stages of the seminiferous epithelial cycle. the duration of one cycle was 13.5 days, as determined by injections of [(3)h]-thymidine and autoradiographic examination of the most ad ...200415304203
constraint of feeding by chronic ingestion of 1,8-cineole in the brushtail possum (trichosurus vulpecula).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 t ...200415260222
ionic calcium levels in oviduct explant-conditioned media from an australian marsupial, the brushtail possum (trichosurus vulpecula) and its relevance to in vitro fertilization.gametes from the brushtail possum (trichosurus vulpecula), an australian marsupial, require exposure to oviductal cells and/or their secretions before sperm binding and penetration of the zona pellucida can occur. sperm-egg fusion, the next critical step in fertilization has not previously been reported in vitro. here we describe the refinement of an oviduct epithelial cell (oec) explant culture system using two different media to obtain in vitro sperm-egg fusion in the brushtail possum for the ...200315085727
effect of steroid hormones on tissue remodelling and progesterone receptors in the uterus of seasonally anoestrous brushtail possums (trichosurus vulpecula).this study describes progesterone receptor (pr) location within uterine cells and associated morphological changes to the uterine luminal and glandular epithelium in seasonally anoestrous brushtail possums treated with oestradiol and/or progesterone. twenty-four adult female possums (n = 6/group) were treated with oestradiol, progesterone, oestradiol followed by progesterone or with the oil vehicle alone for 6-day periods. uterine tissue was recovered, weighed and processed for light and transmi ...200415056791
body size, age and paternity in common brushtail possums (trichosurus vulpecula).sexual selection should produce sexual size dimorphism in species where larger members of one sex obtain disproportionately more matings. recent theory suggests that the degree of sexual size dimorphism depends on physical and temporal constraints involving the operational sex ratio, the potential reproductive rate and the trade-off between current reproductive effort and residual reproductive value. as part of a large-scale experiment on dispersal, we investigated the mating system of common br ...200414653799
effects of two plant secondary metabolites, cineole and gallic acid, on nightly feeding patterns of the common brushtail possum.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 i ...200312918927
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