a light-microscopic immunocytochemical study of the endocrine pancreas in the australian fat-tailed dunnart (sminthopsis crassicaudata).the endocrine pancreas of the australian fat-tailed dunnart (sminthopsis crassicaudata) was investigated by means of immunocytochemistry using the avidin-biotin-peroxidase technique. this was a light microscopic study using this established technique and has not been previously investigated. serial paraffin sections were stained individually with primary antibodies for anti-porcine glucagon, anti-beef pork insulin, anti-human somatostatin, and anti-avian pancreatic polypeptide (app), anti-bovine ...19921352914
widespread expression of the testis-determining gene sry in a marsupial.there is compelling evidence from mutation analysis and transgenesis that the sry gene isolated from human and mouse encodes the testis-determining factor on the mammalian y chromosome. however, how sry achieves this function is unclear. although marsupials have been separated from eutherian mammals for approximately 100 million years, homologues of sry have been localised to the y chromosome of two unrelated marsupial species, the tammar wallaby and the darling downs dunnart. gonadal developmen ...19957581465
cephalic morphology of the honey possum, tarsipes rostratus (marsupialia: tarsipedidae); an obligate nectarivore.the sharply tapering skull of the honey possum is delicately constructed and has only a few, minute teeth; its mandible is reduced to a thin, flexible rod. the mandibular fossa has been displaced caudally to the caudomedial corner of the squamosal. head skeletons of the feathertail glider and western pygmy-possum, omnivores that are closely related to the honey possum, bear greater resemblance to the distantly related carnivorous fat-tailed dunnart than to the honey possum. selected muscles asso ...19957714906
embryonic development in culture of the marsupials antechinus stuartii (macleay) and sminthopsis macroura (spencer) during preimplantation stages.forty-nine blastocysts from 11 brown antechinus, antechinus stuartii, and 96 blastocysts from 17 stripe-faced dunnarts, sminthopsis macroura, were used to develop a culture system for embryos during preimplantation stages. blastocysts of brown antechinus were collected on days 6-9 for unilaminar stages, days 16-21 for bilaminar stages and days 20 and 21 for trilaminar stages. blastocysts of stripe-faced dunnarts were collected on day 6 for unilaminar stages, days 6-8 for bilaminar stages and day ...19938153394
alterations in composition and function of surfactant associated with torpor in sminthopsis crassicaudata.cold profoundly influences lung compliance in homeothermic mammals. much of this effect has traditionally been attributed to the inactivation of the surfactant system. however, many mammals undergo large fluctuations in body temperature (heterothermic mammals). here, the surfactant lipid composition and lung compliance of warm-active dunnarts (sminthopsis crassicaudata) and the homeothermic mouse (mus musculus) [body temperature (tb) = 35-37 degrees c] were compared with those of dunnarts killed ...19968770146
nutrient uptake and culture of sminthopsis macroura (stripe-faced dunnart) embryos.glucose and pyruvate uptake by individual embryos were measured in a marsupial species (stripe-faced dunnart) and a eutherian species (mouse). at each stage of development, nutrient uptake by the dunnart embryo was around an order of magnitude greater than that of the mouse embryo. the pattern of glucose uptake by the dunnart embryo was not like that for any eutherian embryo, all of which have a low glucose uptake before the blastocyst stage. rather, in the dunnart embryo there was a significant ...19968870091
daily restricted feeding effects on the circadian activity rhythms of the stripe-faced dunnart, sminthopsis macroura.the effect of daily restricted feeding (rf) on the circadian wheel-running activity rhythms of the stripe-faced dunnart (sminthopsis macroura) was examined. dunnarts were presented with a 2-h meal in the middle of the light period of a 14:10 light:dark (ld) cycle and during constant dim light (ll). no meal-anticipatory activity (aa) was observed in any of the dunnarts during the experiment. this contrasts with previous work where aa has been reported in dunnarts subjected to rf. in ll, rf acted ...19968872591
antiserum to the egg coats of the fat-tailed dunnart (marsupialia, dasyuridae) cross-reacts with egg coats of other marsupial and eutherian species.we are examining the extracellular coats of the brush-tailed possum as a possible target for an immunocontraceptive vaccine for biocontrol of this pest species in new zealand. in this study we have compared the composition of the extracellular coats of the fat-tailed and stripe-faced dunnarts, brush-tailed possum, domestic rabbit, and laboratory mouse using histochemistry, immunocytochemistry, and immunofluorescence. the histochemistry of the luminal epithelium of the oviduct and mucoid coats of ...19979181693
evolution of shorter and more hydrophilic transthyretin n-termini by stepwise conversion of exon 2 into intron 1 sequences (shifting the 3' splice site of intron 1)transthyretin cdna was cloned from eastern grey kangaroo liver and its nucleotide sequence determined. analysis of the derived amino acid sequence of kangaroo transthyretin, together with data obtained previously for transthyretins from other vertebrate species [duan, w., richardson, s. j., babon, j. j., heyes, r. j., southwell, b. r., harms, p. j., wettenhall, r. e. h., dziegielewska, k. m., selwood, l., bradley, a. j., brack, c. m. & schreiber, g. (1995) eur. j. biochem. 227, 396-406], showed ...19979208931
development of primary visual projections occurs entirely postnatally in the fat-tailed dunnart, a marsupial mouse, sminthopsis crassicaudata.we have examined the development of retinal projections in a diminutive polyprotodont marsupial, the fat-tailed dunnart, sminthopsis crassicaudata. here, we document the most immature mammalian visual system at birth described to date. at postnatal day (p) 0, the retinal ganglion cell layer has yet to form, and axons have not entered the optic stalk. by p4, the retinal ganglion cell layer could be distinguished at the posterior pole, and the front of growing axons extended one-third the length o ...19979214538
effects of cabergoline on reproduction in three families of australian marsupials.the effects of the prolactin inhibiting drug, cabergoline, on pregnant and lactating marsupials were investigated in four species from three diverse families: the tammar wallaby, macropus eugenii, the quokka, setonix brachyurus, the brushtail possum, trichosurus vulpecula, and the fat-tailed dunnart, sminthopsis crassicaudata. in tammar wallabies, 20 micrograms cabergoline kg-1 injected intramuscularly 1 day before expected birth did not alter the timing of parturition but neonates died within a ...19989713388
anatomical comparison of the macaque and marsupial visual cortex: common features that may reflect retention of essential cortical elements.this study identifies fundamental anatomical features of primary visual cortex, area v1 of macaque monkey cerebral cortex, i.e., features that are present in area v1 of phylogenetically distant mammals of quite different lifestyle and features that are common to other regions of cortex. we compared anatomical constituents of macaque v1 with v1 of members of the two principal marsupial lines, the dunnart and the quokka, that diverged from the eutherian mammalian line over 135 million years ago. f ...19989786408
isolation and characterization of marsupial il5 genes.the genomic nucleotide sequence and chromosomal position of the interleukin 5 (il5) gene has been described for the model marsupial macropus eugenii (tammar wallaby). a 272 base pair genomic il5 polymerase chain reaction (pcr) product spanning exon 3, intron 3, and exon 4 was generated using stripe-faced dunnart (sminthopsis macroura) dna. this pcr product was used to isolate a genomic lambda clone containing the complete il5 gene from a tammar wallaby embl3 lambda library. sequencing revealed t ...199910501836
absence of sox3 in the developing marsupial gonad is not consistent with a conserved role in mammalian sex determination.expression of sox3 has been detected in the testes of humans and of developing and adult mice at the same time as sox9 and sry. the co-expression of these three related sox genes in the mouse indifferent gonadal ridge led to the hypothesis that these three genes, encoding transcription factors with similar dna target binding sites, may interact with each other in initiating testis differentiation. the location of sox3 on the marsupial dunnart x chromosome also makes it a candidate for the marsup ...200010992324
a staging scheme for assessing development in vitro of organogenesis stage embryos of the stripe-faced dunnart, sminthopsis macroura (marsupialia: dasyuridae).the inaccessibility of mammalian organogenesis stage embryos has precluded their widespread use in embryological and teratological studies. as organogenesis occurs during the last 1.5 days of the 10. 7 days of gestation in the stripe-faced dunnart (sminthopsis macroura), the aim of the present study was to investigate whether day 9 and day 10 embryos and fetuses could be grown to term in vitro. high glucose dulbecco's modified eagle's medium with 10% fetal calf serum (fcs) supported embryonic gr ...200011006151
cloning of leptin cdna and assignment to the long arm of chromosome 5 in the marsupial sminthopsis crassicaudata.we have isolated and sequenced full-length cdna clones for leptin in the dasyurid marsupial sminthopsis crassicaudata (fat-tailed dunnart). southern and in situ hybridisation data indicated a single leptin gene in the s. crassicauda- ta genome, localised to arbitrary chromosome bands 5q24--> q31 on the long arm of chromosome 5, the short-arm terminus of which bears the only nucleolar organising region. the nucleotide sequence of the cdnas revealed that the primary translation product of s. crass ...200011060440
the development and mature organisation of the end-artery retinal vasculature in a marsupial, the dunnart sminthopsis crassicaudata.the end-artery retinal vasculature of a marsupial, the fat-tailed dunnart, was defined by india ink injection and studied in wholemounts. in the adult, the vitreal vasculature supplying the ganglion-cell layer has major paired-vessels in a horizontal h shape. these vessels skirt the area centralis and visual streak that are supplied by fine end-loops. a second vascular layer of uniformly distributed endloops arises from the superficial vessels and lies at the inner nuclear/outer plexiform border ...200111163612
the minimal mammalian y chromosome - the marsupial y as a model system.the mammalian x and y chromosomes are very different in size and gene content. the y chromosome is much smaller than the x and consists largely of highly repeated non-coding dna, containing few active genes. the 65-mb human y is homologous to the x over two small pseudoautosomal regions which together contain 13 active genes. the heterochromatic distal half of the human yq is entirely composed of highly repeated non-coding dna, and even the euchromatic portion of the differential region is large ...200011173870
neurochemical and thermal control of surfactant secretion by alveolar type ii cells isolated from the marsupial, sminthopsis crassicaudata.pulmonary surfactant is synthesised in alveolar type ii cells and secreted into the lining of the lung in response to ventilation, temperature changes and autonomic neurotransmitters. type ii cells were isolated from the heterothermic marsupial, sminthopsis crassicaudata. the neurotransmitters, isoproterenol and carbamylcholine chloride significantly increased phosphatidylcholine secretion at 37 degrees c (basal: 14.2%, isoproterenol: 20.1%, carbamylcholine: 17.0%). temperature reduced the rate ...200111352105
the roles of cholesterol in pulmonary surfactant: insights from comparative and evolutionary most eutherian mammals, cholesterol (chol) comprises approximately 8-10 wt.% or 14-20 mol.% of both alveolar and lamellar body surfactant. it is regarded as an integral component of pulmonary surfactant, yet few studies have concentrated on its function or control. throughout the evolution of the vertebrates, the contribution of cholesterol relative to surfactant phospholipids decreases, while that of the disaturated phospholipids (dsp) increases. chol generally appears to dominate in animals ...200111369535
induced ovulation, mating success and embryonic development in the stripe-faced dunnart, sminthopsis macroura.induced ovulation resulting in normal embryos is rare in marsupials. in this study natural and induced ovulations were compared in mature sminthopsis macroura (n = 122). comparison of maturation of preovulatory oocytes by ovarian histology and examination of oocytes removed from developing follicles in 12 ovaries of 23 animals receiving 0.058 iu equine serum gonadotrophin (esg) g(-1) with ovaries of 12 animals undergoing natural cycles showed that oocyte maturation was significantly more irregul ...200111690538
comparative and functional analyses of lyl1 loci establish marsupial sequences as a model for phylogenetic footprinting.comparative genomic sequence analysis is a powerful technique for identifying regulatory regions in genomic dna. however, its utility largely depends on the evolutionary distances between the species involved. here we describe the screening of a genomic bac library from the stripe-faced dunnart, sminthopsis macroura, formerly known as the narrow-footed marsupial mouse. we isolated a clone containing the lyl1 locus, completely sequenced the 60.6-kb insert, and compared it with orthologous human a ...200312659809
the cardiac innervation of a marsupial heterotherm, the fat-tailed dunnart (sminthopsis crassicaudata).this study investigated the pattern of autonomic innervation of the heart of the fat-tailed dunnart (sminthopsis crassicaudata) using isolated cardiac preparations. while the pattern of autonomic innervation of the atria was consistent with that found in other mammals, the ventricles displayed an unusual pattern of mammalian cardiac innervation. transmural stimulation of the intramural nerves of isolated right ventricular preparations caused a decrease in the force of contraction of 46.8+/-3.2% ...200312820007
peri-gastrulation development of the dasyurid marsupial sminthopsis macroura (stripe-faced dunnart) in vitro and evidence for patterning of the epiblast prior to gastrulation.marsupials are potentially excellent models for the study of gastrulation because of their superficial embryonic area (ea), post-gastrulation implantation and their potential to provide information about the evolution of gastrulation. very few studies have examined this developmental period in marsupials. using an established developmental timetable, peri-gastrula stage sminthopsis macroura blastocysts were collected and described in detail by observations on live blastocysts and by the use of h ...200312840814
configural learning in two species of marsupial (setonix brachyurus and sminthopsis crassicaudata).four experiments examined the ability of quokkas (setonix brachyurus) and fat-tailed dunnarts (sminthopsis crassicaudata) to solve 2 configural tasks: transverse and negative patterning. transverse patterning requires the simultaneous solution of 3 overlapping discrimination problems (a+ b-, b+ c-, c+ a-). both species could solve the nonoverlapping (elemental) version of this task (u+ v-, w+ x-, y+ z-), but only dunnarts solved the transverse patterning task. negative patterning requires condit ...200312856789
cone visual pigments of the australian marsupials, the stripe-faced and fat-tailed dunnarts: sequence and inferred spectral properties.studies of color vision in marsupial mammals have been very limited. two photoreceptor genes have been characterized from the tammar wallaby, but a third cone pigment was suggested by microspectrophotometric measurements on cone photoreceptors in two other species, including the fat-tailed dunnart, sminthopsis crassicaudata. to determine the sequence and infer absorption maxima of the cone photoreceptor pigments of s. crassicaudata and the related stripe-faced dunnart (sminthopsis macroura), we ...200415518192
studies of learning and problem solving in two species of australian marsupials.this article reviews the authors' recent work with two species of australian marsupials on several learning and conditioning experiments. the quokka (setonix brachyurus) is a cat-sized herbivorous wallaby that inhabits offshore islands around south-western australia. the fat-tailed dunnart (sminthopsis crassicaudata) is a mouse-sized carnivorous marsupial that inhabits much of inland australia. both species were successful in learning simple discriminations, learning sets and reversal sets. quok ...200415527864
effect of torpor on the water economy of an arid-zone marsupial, the stripe-faced dunnart (sminthopsis macroura).metabolic rate and evaporative water loss (ewl) were measured for a small, arid-zone marsupial, the stripe-faced dunnart (sminthopsis macroura), when normothermic and torpid. metabolic rate increased linearly with decreasing ambient temperature (t(a)) for normothermic dunnarts, and calculated metabolic water production (mwp) ranged from 0.85+/-0.05 (t(a)=30 degrees c) to 3.13+/-0.22 mg h2o g(-1) h(-1) (t(a)=11 degrees c). torpor at t(a)=11 and 16 degrees c reduced mwp to 24-36% of normothermic v ...200515864500
cone topography and spectral sensitivity in two potentially trichromatic marsupials, the quokka (setonix brachyurus) and quenda (isoodon obesulus).the potential for trichromacy in mammals, thought to be unique to primates, was recently discovered in two australian marsupials. whether the presence of three cone types, sensitive to short- (sws), medium- (mws) and long- (lws) wavelengths, occurs across all marsupials remains unknown. here, we have investigated the presence, distribution and spectral sensitivity of cone types in two further species, the quokka (setonix brachyurus) and quenda (isoodon obesulus). immunohistochemistry revealed th ...200515888411
dipalmitoylphosphatidylcholine is not the major surfactant phospholipid species in all mammals.pulmonary surfactant, a complex mixture of lipids and proteins, lowers the surface tension in terminal air spaces and is crucial for lung function. within an animal species, surfactant composition can be influenced by development, disease, respiratory rate, and/or body temperature. here, we analyzed the composition of surfactant in three heterothermic mammals (dunnart, bat, squirrel), displaying different torpor patterns, to determine: 1) whether increases in surfactant cholesterol (chol) and ph ...200516037124
the corneal epithelial surface in the eyes of vertebrates: environmental and evolutionary influences on structure and function.the smooth optical surface of the cornea is maintained by a tear film, which adheres to a variety of microprojections. these microprojections increase the cell surface area and are thought to improve the movement of oxygen, nutrients, and metabolic products across the outer cell membranes. however, little is known of these structural adaptations in vertebrates inhabiting different environments. this field emission scanning electron microscopic study examined the cell density and surface structur ...200616323209
characterization of two whey protein genes in the australian dasyurid marsupial, the stripe-faced dunnart (sminthopsis macroura).we report the first isolation and sequencing of genomic bac clones containing the marsupial milk protein genes whey acidic protein (wap) and early lactation protein (elp). the stripe-faced dunnart wapgene sequence contained five exons, the middle three of which code for the wapmotifs and four disulphide core domains which characterize wap. the dunnart elpgene sequence contained three exons encoding a protein with a kunitz motif common to serine protease inhibitors. fluorescence in situ hybridiza ...200616974085
induction of ovulation and natural oestrous cycling in the stripe-faced dunnart, sminthopsis macroura.induced ovulation allows reproduction by otherwise infertile females, and is ideal for the captive breeding of endangered species where the population is aged or breeding is unsuccessful. a predictable time of ovulation after induction has not yet been achieved in polyovular marsupials. ovulation was induced in sminthopsis macroura using an initial injection of 20 iu equine serum gonadotrophin (esg; day 0), followed on day 4 by either 20 iu esg (n = 25) or 0.5 mg porcine luteinizing hormone (n = ...200717307917
the unique paired retinal vascular pattern in marsupials: structural, functional and evolutionary perspectives based on observations in a range of the few marsupial species studied to date that possess a retinal vasculature, the arterial and venous segments, down to the smallest calibre capillaries, have been shown to occur in pairs. it is a pattern seen in the marsupial central nervous system (cns) but not in other tissues in this group or in any tissues in eutherian mammals. the aim of the present study was to investigate the presence of retinal vessels in a range of non-eutherian mammalian species (marsupials and monotremes) and to d ...200717475712
identification of novel and known ovary-specific genes including zp2, in a marsupial, the stripe-faced dunnart.during the early stages of oogenesis, oocyte-specific factors, synthesized by and stored within the oocyte, play critical roles during oogenesis, folliculogenesis, fertilization and early embryonic development in the mouse. the identification of marsupial maternal factors, expressed specifically in the ovary or oocyte, may provide an insight into the conserved evolutionary mechanisms that drive mammalian oocyte development to cleavage stages. in this study, 10 clones including dunnart zp2 and c- ...200817597472
torpor and basking in a small arid zone marsupial.the high energetic cost associated with endothermic rewarming from torpor is widely seen as a major disadvantage of torpor. we tested the hypothesis that small arid zone marsupials, which have limited access to energy in the form of food but ample access to solar radiation, employ basking to facilitate arousal from torpor and reduce the costs of rewarming. we investigated torpor patterns and basking behaviour in free-ranging fat-tailed dunnarts sminthopsis crassicaudata (10 g) in autumn and wint ...200817684718
isolation and characterization of melanopsin (opn4) from the australian marsupial sminthopsis crassicaudata (fat-tailed dunnart).melanopsin confers photosensitivity to a subset of retinal ganglion cells and is responsible for many non-image-forming tasks, like the detection of light for circadian entrainment. recently, two melanopsin genes, opn4m and opn4x, were described in non-mammalian vertebrates. however, only one form, opn4m, has been described in the mammals, although studies to date have been limited to the placentals and have not included the marsupials. we report here the isolation and characterization of an opn ...200717785267
cortical cyto- and chemoarchitecture in three small australian marsupial carnivores: sminthopsis macroura, antechinus stuartii and phascogale calura.the cyto- and chemoarchitecture of the cerebral cortex has been examined in three small (mouse-sized) polyprotodont marsupial carnivores from australia (the stripe-faced dunnart, sminthopsis macroura; the brown antechinus, antechinus stuartii; and the red-tailed phascogale, phascogale calura) in order to compare the cortical topography of these marsupials with that of diprotodontids, didelphids and eutherians. all three species studied had similar cortical cytoarchitecture. the isocortical surfa ...200818946209
comparison of the production, quality, and in vitro maturation capacity of oocytes from untreated cycling and intermediate phase equine serum gonadotropin-treated fat-tailed dunnarts (sminthopsis crassicaudata).this study describes ovarian changes during the natural and stimulated reproductive cycle of breeding (< or =12 month) and retired (>12 month) fat-tailed dunnarts, sminthopsis crassicaudata. increased urinary cornified epithelial cells and the influx of leukocytes defined day 0, at which time the naturally cycling females had already ovulated; at day 16 females had no antral follicles, but by day 20 antral follicles had begun to develop. there was no difference between naturally cycling breeding ...200919380426
induced ovulation mimics the time-table of natural development in the stripe-faced dunnart, sminthopsis macroura and results in the birth of fertile young.induced ovulation maximizes captive breeding success, increasing productivity and facilitating the contribution of otherwise infertile animals to the genetic pool. in marsupials, induced ovulation to produce fertile young is unknown. here we present an induction protocol efficient in inducing non-cycling and non-reproductive females to cycle, mate, ovulate, and conceive. ovulation was induced in sminthopsis macroura using an initial injection of 0.06 iu equine serum gonadotropin (esg)/g (time 0) ...201019900987
diversity of color vision: not all australian marsupials are trichromatic.color vision in marsupials has recently emerged as a particularly interesting case among mammals. it appears that there are both dichromats and trichromats among closely related species. in contrast to primates, marsupials seem to have evolved a different type of trichromacy that is not linked to the x-chromosome. based on microspectrophotometry and retinal whole-mount immunohistochemistry, four trichromatic marsupial species have been described: quokka, quenda, honey possum, and fat-tailed dunn ...201021151905
acute oral toxicity of the organophosphorus pesticide fenitrothion to fat-tailed and stripe-faced dunnarts and its relevance for pesticide risk assessments in australia.the scarcity of information on the effects of pesticides on native australian vertebrates constrains the development of biologically relevant risk assessments in australia for the registration of pesticides. the concern that endemically old and unique australian vertebrate fauna might display high sensitivity to pesticides used for locust control provoked examination of the acute oral toxicity of the organophosphorus pesticide fenitrothion for the fat-tailed dunnart, sminthopsis crassicaudata (g ...201121305579
did transmission of helicobacter pylori from humans cause a disease outbreak in a colony of stripe-faced dunnarts (sminthopsis macroura)?abstract: since the discovery that helicobacter pylori causes a range of pathologies in the stomachs of infected humans, it has become apparent that helicobacters are found in a diverse range of animal species where they are frequently associated with disease. in 2003 and 2004, there were two outbreaks of increased mortality associated with gastric bleeding and weight-loss in a captive colony of the australian marsupial, the stripe-faced dunnart (sminthopsis macroura). the presence of gastric pa ...201121314909
extensive production of neospora caninum tissue cysts in a carnivorous marsupial succumbing to experimental neosporosis.abstract: experimental infections of sminthopsis crassicaudata, the fat-tailed dunnart, a carnivorous marsupial widely distributed throughout the arid and semi-arid zones of australia, show that this species can act as an intermediate host for neospora caninum. in contrast to existing models that develop relatively few n. caninum cysts, dunnarts offer a new animal model where active neosporosis is dominated by tissue cyst production. the results provide evidence for a sylvatic life cycle of n. c ...201121635733
morphological observations on sperm-egg interactions during in vivo fertilization in the dasyurid marsupial sminthopsis crassicaudata.the aim of the present study was to determine the morphological changes that take place in the male and female gametes during in vivo fertilization in the australian marsupial, the fat-tailed dunnart, sminthopsis crassicaudata. plastic sections were cut of sperm and eggs recovered from the oviducts of recently mated individuals, and light microscopy of thick, and transmission em of thin, sections was carried out. it was found that, before penetration of the zona, the spermatozoon came to lie alo ...20113209177
development in vitro of investment-free marsupial embryos during cleavage and early blastocyst formation.twenty embryos at the cleavage-arrested four-cell stage of the brown antechinus, antechinus stuartii, were used to develop a method to obtain investment-free embryos by incubation at 35 degrees c in 2.5% pancreatin, 0.05% trypsin, and 0.05% pronase. control intact embryos and the investment-free embryos were incubated in dulbecco's modified eagle's medium with high glucose and 10% foetal calf serum in 5% co2 in air at 35 degrees c for 48 h. release of embryos from the investments (shell, mucoid, ...20092777174
time-lapse analysis and normal stages of development of cleavage and blastocyst formation in the marsupials the brown antechinus and the stripe-faced dunnart.the first six normal stages of cleavage and blastocyst formation in vitro of the brown antechinus and the stripe-faced dunnart are described based on 429 embryos from 37 dunnarts and 143 embryos from 32 antechinus and an information from previous studies. embryos were cultured in dulbecco's modified eagle's medium with high glucose and 10% foetal calf serum at 35 degrees c and 5% co2 in air. seven antechinus and 18 dunnart embryos were cultured in rose chambers and filmed by time-lapse cinematog ...20082346646
the mammary gland-specific marsupial elp and eutherian cti share a common ancestral gene.the marsupial early lactation protein (elp) gene is expressed in the mammary gland and the protein is secreted into milk during early lactation (phase 2a). mature elp shares approximately 55.4% similarity with the colostrum-specific bovine colostrum trypsin inhibitor (cti) protein. although elp and cti both have a single bovine pancreatic trypsin inhibitor (bpti)-kunitz domain and are secreted only during the early lactation phases, their evolutionary history is yet to be investigated.201222681678
differential ifn-γ and tnf-α driven cytokine response distinguishes acute infection of a metatherian host with toxoplasma gondii and neospora caninum.toxoplasma gondii and neospora caninum (both apicomplexa) are closely related cyst-forming coccidian parasites that differ significantly in their host range and ability to cause disease. unlike eutherian mammals, australian marsupials (metatherian mammals) have long been thought to be highly susceptible to toxoplasmosis and neosporosis because of their historical isolation from the parasites. in this study, the carnivorous fat-tailed dunnart (sminthopsis crassicaudata) was used as a disease mode ...201728348050
the type and differentiation of cells in vitro from unilaminar and bilaminar blastocysts of two marsupials, antechinus stuartii and sminthopsis macroura.the type and ability to differentiate in vitro of cells found in blastocysts of two marsupials were examined. thirteen unilaminar blastocysts on day 7 to day 12 of gestation and 24 bilaminar blastocysts on day 16 and day 18 of gestation were collected from 11 brown antechinus, antechinus stuartii. a total of of 77 unilaminar blastocysts on day 5 and day 6 of gestation and a total of 61 bilaminar blastocysts on day 6 and day 7 of gestation were collected from 40 stripe-faced dunnarts, sminthopsis ...19968870095
interspecific variation of zona pellucida glycoconjugates in several species of marsupial.the zona pellucida glycoconjugate content of several marsupial species was investigated using differential lectin histochemistry. ovaries from fat-tailed dunnarts, a southern brown bandicoot, grey short-tailed opossums, brushtail possums, ringtail possums, koalas and eastern grey kangaroos were fixed, embedded in paraffin wax, sectioned and stained with ten fluorescein isothiocyanate-conjugated lectins. sections were also incubated with either neuraminidase or saponified, respectively, before in ...200010864820
retinal structure and visual acuity in a polyprotodont marsupial, the fat-tailed dunnart (sminthopsis crassicaudata).the visual system of the fat-tailed dunnart (sminthopsis crassicaudata), a small polyprotodont marsupial, has been examined both anatomically and behaviourally. the ganglion cell layer was examined in cresyl-violet stained wholemounts and found to contain a mean of 81,400 ganglion cells (sd +/- 3,360); the identification of ganglion cells was supported by a correspondence to optic axon counts. ganglion cells were distributed as a mid-temporally situated area centralis, embedded in a pronounced v ...199910085478
the ipsilateral retinal projection in the fat-tailed dunnart, sminthopsis crassicaudata.the population of retinal ganglion cells which project ipsilaterally in the brain was examined in the fat-tailed dunnart, sminthopsis crassicaudata, following injection of horseradish peroxidase into one optic tract. retinae were examined as wholemounts and optic nerves as serial sections. in addition, visual fields were measured ophthalmoscopically. ipsilaterally projecting ganglion cells were located temporal to a line which ran vertically through the middle of the area centralis and extended ...20069682869
expression analysis of cdx2 and pou5f1 in a marsupial, the stripe-faced dunnart, during early development.the first lineage allocation during mouse development forms the trophectoderm and inner cell mass, in which cdx2 and pou5f1 display reciprocal expression. yet cdx2 is not required for trophectoderm specification in other mammals, such as the human, cow, pig, or in two marsupials, the tammar and opossum. the role of cdx2 and pou5f1 in the first lineage allocation of sminthopsis macroura, the stripe-faced dunnart, is unknown. in this study, expression of cdx2 and pou5f1 during oogenesis, developme ...201626613191
scanning electron microscopy reveals two distinct classes of erythroblastic island isolated from adult mammalian bone marrow.erythroblastic islands are multicellular clusters in which a central macrophage supports the development and maturation of red blood cell (erythroid) progenitors. these clusters play crucial roles in the pathogenesis observed in animal models of hematological disorders. the precise structure and function of erythroblastic islands is poorly understood. here, we have combined scanning electron microscopy and immuno-gold labeling of surface proteins to develop a better understanding of the ultrastr ...201626898901
a light-microscopic immunocytochemical study of the endocrine pancreas in the australian brush-tailed possum (trichosurus vulpecula).the endocrine pancreas of the australian brush-tailed possum (trichosurus vulpecula) was investigated by means of immunocytochemistry using the avidin-biotin-peroxidase technique. this was a light microscopic study using this established technique. serial paraffin sections were stained individually with primary antibodies for glucagon, insulin, somatostatin, and pancreatic polypeptide (pp), showing the same islet. cells immunoreactive to glucagon, insulin, somatostatin and pp were found in endoc ...19921380858
myosin isoforms and fibre types in jaw-closing muscles of australian marsupials.myosin heavy chains (myhcs) and fibre types in the masseter muscle of seven species of australian marsupials (brushtail and ringtail possums, bettong, bandicoot, dunnart, two species of antechinuses) spanning three orders were studied by native myosin electrophoresis, sds-page, immunoblotting and immunohistochemistry. we found only two fibre types in the masseter muscles of these animals: (1) masticatory fibres expressing masticatory myhc, and (2) hybrid alpha/beta fibres that co-express alpha-c ...200616773370
control of pulmonary surfactant secretion: an evolutionary perspective.pulmonary surfactant, a mixture consisting of phospholipids (pl) and proteins, is secreted by type ii cells in the lungs of all air-breathing vertebrates. virtually nothing is known about the factors that control the secretion of pulmonary surfactant in nonmammalian vertebrates. with the use of type ii cell cultures from australian lungfish, north american bullfrogs, and fat-tailed dunnarts, we describe the autonomic regulation of surfactant secretion among the vertebrates. ach, but not epinephr ...200010712280
imidacloprid treatment of marsupials for fleas (pygiopsylla hoplia).two eastern barred bandicoots (perameles gunnii), two eastern quells (dasyunrus viverrinus), four fat-tailed dunnarts (sminthopsis crassicaudata), a leadbeater's possum (gymnobelideus leadbeateri), a yellow-bellied glider (petaurus australis), and a ring-tailed possum (pseudocheirus peregrinus) were treated with imidacloprid (10.7 +/- 0.6 mg/kg topically, minimum dose 0.5 mg) after observation of fleas (pygiopsylla hoplia) on animals and in their nest boxes. no live fleas or adverse reactions to ...200112785692
identification of the mrna encoding interleukin-6 and its receptor, interleukin-6 receptor α, in five marsupial species.expressed coding sequences for interleukin-6 (il-6) and interleukin-6 receptor α (il-6r) were examined in five marsupial species. full length expressed coding sequences for il-6 and il-6r were identified and characterized in the gray short-tailed opossum (monodelphis domestica). for il-6, ∼225 bp fragments of the mrna sequence were identified in the red-tailed phascogale (phascogale calura), kultarr (antechinomys laniger), and stripe-faced dunnart (sminthopsis macroura), while ∼563 bp fragments ...201627431929
hormones of oestrus and ovulation and their manipulation in marsupials.oestrus and ovulation occur spontaneously in the majority of marsupials, with behavioural oestrus usually occurring 1-2 days before ovulation. the hormone changes that occur at this time have been described in the most detail for the monovular tammar wallaby macropus eugenii. the respective roles of the graafian follicle, corpus luteum and the pituitary in the events leading up to oestrus and ovulation in this species are also reviewed. recently, various protocols have been developed for superov ...19968870088
the rod opsin pigments from two marsupial species, the south american bare-tailed woolly opossum and the australian fat-tailed dunnart.rod visual pigment genes have been studied in a wide range of vertebrates including a number of mammalian species. however, no marsupials have yet been examined. to correct this omission, we have studied the rod pigments in two marsupial species, the nocturnal and frugivorous bare-tailed woolly opossum, caluromys philander, from central and south america, and the arhythmic and insectivorous fat-tailed dunnart, sminthopsis crassicaudata, from australia. phylogenetic analysis establishes that the ...200314659889
organization of somatosensory cortex in three species of marsupials, dasyurus hallucatus, dactylopsila trivirgata, and monodelphis domestica: neural correlates of morphological specializations.the organization of somatosensory neocortex was investigated in three species of marsupials, the northern quoll (dasyurus hallucatus), the striped possum (dactylopsila trivirgata), and the short-tailed opossum (monodelphis domestica). in these species, multiunit microelectrode mapping techniques were used to determine the detailed organization of the primary somatosensory area (si). in the striped possum and quoll, the topography of somatosensory regions rostral (r), and caudal (c) to si were de ...199910075440
retinal projections in two australian polyprotodont marsupials: kowari, dasyuroides byrnei, and fat-tailed dunnart, sminthopsis crassicaudata (dasyuridae).retinal projections were examined in two small dasyurids, the kowari and the fat-tailed dunnart, following injections of 3h-proline into one eye. in both animals retinal fibres terminate in the dorsal and ventral lateral geniculate nuclei (lgd, lgv), the lateral posterior nuclear complex, the pretectum, the superior colliculus, the suprachiasmatic nucleus of the hypothalamus and the nuclei of the accessory optic system. the lateroposterior thalamic complex and the accessory optic nuclei receive ...19883349353
acrosomal integrity, viability, and dna damage of sperm from dasyurid marsupials after freezing or freeze drying.dasyurids are a diverse group of australian native carnivores and insectivores that contains several threatened species. despite successful cryopreservation of sperm from several marsupials, only 3% postthaw motility is reported for dasyurid marsupials. this study examined sperm preservation in the fat-tailed dunnart (sminthopsis crassicaudata), an experimental model, with supplementary observations on the eastern quoll (dasyurus viverrinus) and northern quoll (dasyurus hallucatus). in s. crassi ...200919616836
acrosome stability in the spermatozoa of dasyurid marsupials.the spermatozoa of most marsupials lack nuclear stabilising disulfide-bonded protamines found in eutherian mammals. however, disulfide stabilisation has been observed in the acrosome of macropodid (macropus eugenii) and phalangerid (trichosurus vulpecula) marsupials. as a result this organelle, which is normally fragile in eutherian mammals, is robust and able to withstand physical and chemical challenge in these marsupials. the present study examined acrosomal characteristics of the spermatozoa ...200818255019
combined mitochondrial and nuclear dna sequences resolve the interrelations of the major australasian marsupial radiations.australasian marsupials include three major radiations, the insectivorous/carnivorous dasyuromorphia, the omnivorous bandicoots (peramelemorphia), and the largely herbivorous diprotodontians. morphologists have generally considered the bandicoots and diprotodontians to be closely related, most prominently because they are both syndactylous (with the 2nd and 3rd pedal digits being fused). molecular studies have been unable to confirm or reject this syndactyla hypothesis. here we present new mitoc ...200616507529
perivitelline space of marsupial oocytes: extracellular matrix of the unfertilized oocyte and formation of a cortical granule envelope following the cortical reaction.the purpose of this study was to characterize the structure of the vestments surrounding unfertilized and cortical granule-reacted oocytes from a marsupial, the grey short-tailed opossum monodelphis domestica and to determine if a cortical granule envelope (cge) forms in the perivitelline space (pvs) following the cortical reaction. unfertilized oocytes collected from mature ovarian follicles and oviducal oocytes that had undergone a cortical reaction were fixed for electron microscopy in the pr ...19958588937
development of early cell lineages in marsupial embryos: an overview.all major embryonic and extra-embryonic cell lineages are established before implantation in marsupials. in reptiles, birds, monotremes and most marsupials, the zygote is polarized, sometimes markedly so, and the cleavage pattern in relation to the polarized state provides the mechanism for the generation of positional signals. these ensure that the embryonic cell lineages develop in the centre of the developing blastoderm or blastocyst epithelium and the extra-embryonic lineages at the peripher ...19947878224
effect of cooling and cryopreservation on sperm motility and morphology of several species of marsupial.the effects of long-term cooling and freezing on sperm motility are described for six marsupial species: the fat-tailed dunnart, koala, brushtail possum, long-footed potoroo, northern brown bandicoot and ring-tailed possum. the effects of up to eight days of cooling at 4 degrees c on the motility of dunnart spermatozoa and the effect of cryopreservation on spermatozoa of the other species were determined. the cryoprotectant used was a tris-citrate-fructose-egg yolk-glycerol diluent. the percenta ...19968870089
phase contrast imaging reveals low lung volumes and surface areas in the developing marsupial.marsupials are born with immature lungs when compared to eutherian mammals and rely, to various extents, on cutaneous gas exchange in order to meet metabolic requirements. indeed, the fat-tailed dunnart is born with lungs in the canalicular stage of development and relies almost entirely on the skin for gas exchange at birth; consequently undergoing the majority of lung development in air. plane radiographs and computed tomography data sets were acquired using phase contrast imaging with a synch ...201323349744
towards a zp-based contraceptive for marsupials: comparative analysis and developmental expression of marsupial zp genes.fertility control in the form of a zona pellucida (zp)-based immunocontraceptive has shown potential as a humane form of control for overabundant marsupials including the brushtail possum and macropods. further refinement and development of a zp-based vaccine requires detailed knowledge of the protein structure and expression in order to ensure maximum efficacy and specificity. sequencing and comparative analysis of the zp3 protein from three marsupial orders in this study found a high overall l ...200717538958
placentation in the dasyurid marsupial, sminthopsis crassicaudata, the fat-tailed dunnart, and notes on placentation of the didelphid, monodelphis domestica.a light microscope study of the choriovitelline (yolk sac) placenta of the dasyurid marsupial, sminthopsis crassicaudata, and some comparative observations on that of the didelphid, monodelphis domestica, were performed. in the former species, the placenta was composed of an invasive bilaminar, avascular, yolk sac and a non-invasive trilaminar, vascular yolk sac. the bilaminar yolk sac placenta had trophoblast giant cells that eroded the maternal epithelium, but there was no evidence of invasion ...19948182576
multiple events of gene manipulation via in pouch electroporation in a marsupial model of mammalian forebrain development.the technique of in utero electroporation has been widely used in eutherians, such as mice and rats, to investigate brain development by selectively manipulating gene expression in specific neuronal populations. a major challenge, however, is that surgery is required to access the embryos, affecting animal survival and limiting the number of times it can be performed within the same litter.201828917658
development of body, head and brain features in the australian fat-tailed dunnart (sminthopsis crassicaudata; marsupialia: dasyuridae); a postnatal model of forebrain formation.most of our understanding of forebrain development comes from research of eutherian mammals, such as rodents, primates, and carnivores. however, as the cerebral cortex forms largely prenatally, observation and manipulation of its development has required invasive and/or ex vivo procedures. marsupials, on the other hand, are born at comparatively earlier stages of development and most events of forebrain formation occur once attached to the teat, thereby permitting continuous and non-invasive exp ...201728880940
epithelial cadherin disassociates from the lateral plasma membrane of uterine epithelial cells throughout pregnancy in a marsupial.the uterine luminal epithelium is the first site of contact between fetal and maternal tissues during therian pregnancy and must undergo specialised changes for implantation of the blastocyst to be successful. these changes, collectively termed the plasma membrane transformation (pmt), allow the blastocyst to attach to the uterine epithelium preceding the formation of a placenta. there are similarities in the morphological and molecular changes occurring in live-bearing eutherian species during ...201728670836
molecular cloning and tissue distribution of crh and pomc mrna in the fat-tailed dunnart (sminthopsis crassicaudata), an australian all vertebrates, marsupials respond to stressors with the activation of the hypothalamo-pituitary-adrenal axis. however, peptides operating at the higher regulatory levels of this hormonal system, i.e. corticotropin-releasing hormone (crh) and adrenocorticotropic hormone (acth), have not been investigated in marsupials. here we report the molecular cloning of the precursor cdnas of crh (prepro-crh) and of acth (proopiomelanocortin; pomc) in an australian marsupial, the fat-tailed dunnart (s ...201728587847
the role of basking in the development of endothermy and torpor in a marsupial.marsupials have a slow rate of development and this allows a detailed examination of thermoregulatory developmental changes and stages. we quantified the cooling rates of marsupial dunnarts (sminthopsis crassicaudata) at 40-56 days (d) old, and torpor and basking behaviour in animals given the option to bask in four age groups from 60 to 150 d. the development of thermoregulation was a continuum, but was characterised by three major thermoregulatory stages: (1) at 40 d, animals were unable to ma ...201728283794
uterine focal adhesion dynamics during pregnancy in a marsupial (sminthopsis crassicaudata; dasyuridae).alterations to the basal attachment points between the epithelium of the uterus and the underlying tissue in early pregnancy affect how easily the epithelium can be invaded by the implanting embryo. attachment points- focal adhesions- disassemble to facilitate highly invasive implantation in rats, but species with less invasive implantation, including marsupials, may require different basal alterations for successful pregnancy. here we used immunofluorescence microscopy and western blotting to c ...201727997081
expression of vegf111and other vegf-a variants in the rat uterus is correlated with stage of pregnancy.vascular endothelial growth factor a is a major mediator of angiogenesis, a critically important process in vertebrate growth and development as well as pregnancy. here we report for the first time the expression of a rare and unusually potent splice variant, vegf111, in vivo in mammals. this variant has previously only been found in mammals in cultured human cells exposed to genotoxic agents. our discovery of vegf111in the uterus of both a eutherian (rat) and a marsupial (fat-tailed dunnart) su ...201727722773
thermoregulatory value of cracking-clay soil shelters for small vertebrates during extreme desert conditions.deserts exhibit extreme climatic conditions. small desert-dwelling vertebrates have physiological and behavioral adaptations to cope with these conditions, including the ability to seek shelter. we investigated the temperature (t) and relative humidity (rh) regulating properties of the soil cracks that characterize the extensive cracking-clay landscapes of arid australia, and the extent of their use by 2 small marsupial species: fat-tailed and stripe-faced dunnarts (sminthopsis crassicaudata and ...201727580346
the functional requirements of mammalian hair: a compromise between crypsis and thermoregulation?mammalian fur often shows agouti banding with a proximal dark band near the skin and a lighter distal band. we examined the function of both bands in relation to camouflage, thermal properties of pelts, and thermal energetics of dunnarts (sminthopsis crassicaudata), which are known to use torpor and basking. although the distal band of dunnart fur darkened with increasing latitude, which is important for camouflage, it did not affect the thermal properties and the length of the dark band and tot ...201627287044
physiological and behavioural responses of a small heterothermic mammal to fire stimuli.the predicted increase of the frequency and intensity of wildfires as a result of climate change could have a devastating impact on many species and ecosystems. however, the particular physiological and behavioural adaptions of animals to survive fires are poorly understood. we aimed to provide the first quantitative data on physiological and behavioural mechanisms used by a small heterothermic marsupial mammal, the fat-tailed dunnart (sminthopsis crassicaudata), that may be crucial for survival ...201526343772
ovarian suppression in a marsupial following single treatment with a gonadotrophin-releasing hormone agonist in microspheres.the effect of treatment with lucrin depot (1 month), a microsphere gonadotrophin-releasing hormone agonist preparation, was investigated in the fat-tailed dunnart (sminthopsis crassicaudata) as a potential strategy to synchronise cycling. the status of the ovaries (ovarian size, number and size of graafian follicles and corpora lutea) and reproductive tract (weight, vascularity and muscularity) in twelve untreated females were assessed to establish the activity parameters for randomly selected c ...201626122537
prioritizing urban habitats for connectivity conservation: integrating centrality and ecological metrics.connectivity among fragmented areas of habitat has long been acknowledged as important for the viability of biological conservation, especially within highly modified landscapes. identifying important habitat patches in ecological connectivity is a priority for many conservation strategies, and the application of 'graph theory' has been shown to provide useful information on connectivity. despite the large number of metrics for connectivity derived from graph theory, only a small number have bee ...201525924790
uterine epithelial cell changes during pregnancy in a marsupial (sminthopsis crassicaudata; dasyuridae).formation of a placenta requires intimate contact between the embryonic and maternal uterine epithelia in early pregnancy. contact is accompanied by a characteristic suite of changes to the plasma membranes of uterine epithelial cells, termed the plasma membrane transformation. the plasma membrane transformation occurs in eutherian mammals and in viviparous (live-bearing) squamate reptiles, and may be fundamental to the evolution of viviparity in amniotes. marsupials provide an excellent opportu ...201424740607
the ventilatory response to hypoxia and hypercapnia is absent in the neonatal fat-tailed birth, the newborn fat-tailed dunnart relies on cutaneous gas exchange to meet metabolic demands, with continuous lung ventilation emerging several days later. we hypothesised that the delayed expression of lung ventilation (v(e)) in these animals is in part due to a low responsiveness of the respiratory control system to blood gas perturbations. to address this hypothesis, we assessed the ventilatory and metabolic response to hypoxia (10% o(2)) and hypercapnia (5% co(2)) using closed-system ...201222972898
developmental phenotypic plasticity in a marsupial.climate change is likely to substantially affect the distribution ranges of species. however, little is known about how different mammalian taxa respond morphologically and physiologically to a rapid change of climate. our objective was to provide the first quantitative data on the effect of continuous cold exposure during development on morphological and functional variables of a marsupial. fat-tailed dunnarts (sminthopsis crassicaudata, dasyuridae) were reared at an ambient temperature (t(a)) ...201222496292
structural and functional development of the respiratory system in a newborn marsupial with cutaneous gas exchange.marsupials are born with structurally immature lungs and rely, to varying degrees, on cutaneous gas exchange. with a gestation of 13 d and a birth weight of 13 mg, the fat-tailed dunnart (sminthopsis crassicaudata) is one of the smallest and most immature marsupial newborns. we determined that the skin is almost solely responsible for gas exchange in the early neonatal period. indeed, fewer than 35% of newborn dunnarts were observed to make any respiratory effort on the day of birth, with pulmon ...201622030856
absence of adaptive nonshivering thermogenesis in a marsupial, the fat-tailed dunnart (sminthopsis crassicaudata).the presence of nonshivering thermogenesis in marsupials is controversially debated. survival of small eutherian species in cold environments is crucially dependent on uncoupling protein 1 (ucp1)-mediated, adaptive nonshivering thermogenesis that is executed in brown adipose tissue. in a small dasyurid marsupial species, the fat-tailed dunnart (sminthopsis crassicaudata), an orthologue of ucp1 has been recently identified which is upregulated during cold exposure resembling adaptive molecular ad ...201222002052
is it or isn't it? a reexamination of the anterior orbital glands of the fat-tailed dunnart sminthopsis crassicaudata (dasyuridae: marsupiala) and a reevaluation of definitions for the harderian gland.the anterior orbital glands of tetrapods, which include the harderian and nictitans glands, can usually be differentiated either anatomically (nictitans gland is more anterior) or histochemically (harderian gland secretes lipids). however, conflicting statements exist in the literature about the presence and identity of these glands. two previous studies on sminthopsis crassicaudata (dasyuridae: marsupiala) either failed to note any anterior ocular glands or used no histochemical analyses. this ...201020665822
coping with chaos: unpredictable food supplies intensify torpor use in an arid-zone marsupial, the fat-tailed dunnart (sminthopsis crassicaudata).the severity, duration and amplitude of extreme weather events are forecast to intensify with current climate trends, over both long (e.g. seasonal) and short (e.g. daily) time-scales. as such, the predictability of food supplies for many small endotherms is likely to become increasingly important. numerous small mammals and birds combat food shortages using torpor, a controlled reduction in metabolic rate and body temperature that helps lower their daily energy requirements. as such, torpor oft ...201020442980
the spermatozoa of the dasyurid marsupial, sminthopsis crassicaudata, are highly susceptible to cold shock.since the late 1970s research has suggested that marsupial spermatozoa did not suffer cold shock. we have re-examined cold shock to investigate problems with freezing of spermatozoa from a dasyurid marsupial, the fat-tailed dunnart (sminthopsis crassicaudata). epididymal spermatozoa were rapidly cooled to 0.5 degrees c in a pre-cooled tube held in an iced-water slurry. upon re-warming all spermatozoa were immotile and the addition of 10% or 20% egg yolk to the sperm medium had no beneficial effe ...201020188031
the energetics of basking behaviour and torpor in a small marsupial exposed to simulated natural information is available on basking behaviour in torpid mammals and its energetic consequences. we investigated the effects of physiological and behavioural strategies on the energetics of the fat-tailed dunnart (sminthopsis crassicaudata). metabolic rate and body temperature during torpor, basking and rest were measured over 24 h in response to simulated environmental conditions: (a) constant ambient temperature (t(a)) of 15 degrees c, (b) constant t(a) of 15 degrees c with access to a ...201019888581
fenitrothion, an organophosphate, affects running endurance but not aerobic capacity in fat-tailed dunnarts (sminthopsis crassicaudata).we measured aerobic metabolism during cold exposure and exercise performance (run duration and oxygen consumption while running at 1 m s(-1)) in the fat-tailed dunnart sminthopsis crassicaudata, a dasyurid marsupial, before and after ingestion of 30 mg kg(-1) of fenitrothion, an organophosphate (op) pesticide. running endurance of op-exposed animals was less than half that of control animals over the first 3 days after dosing and 55% of control animal endurance on day 5 post-dose. despite these ...200818547601
cone visual pigments in two marsupial species: the fat-tailed dunnart (sminthopsis crassicaudata) and the honey possum (tarsipes rostratus).uniquely for non-primate mammals, three classes of cone photoreceptors have been previously identified by microspectrophotometry in two marsupial species: the polyprotodont fat-tailed dunnart (sminthopsis crassicaudata) and the diprotodont honey possum (tarsipes rostratus). this report focuses on the genetic basis for these three pigments. two cone pigments were amplified from retinal cdna of both species and identified by phylogenetics as members of the short wavelength-sensitive 1 (sws1) and l ...200818426754
topographies of retinal cone photoreceptors in two australian marsupials.microspectrophotometry indicates the presence of at least three cone visual pigments in two australian marsupials, the fat-tailed dunnart (sminthopsis crassicaudata) and honey possum (tarsipes rostratus). here we have examined the distribution of cone types using antisera, jh455 and jh492, that recognize short-wavelength-sensitive (sws) and medium-to-long-wavelength-sensitive (m/lws) cone opsins, respectively. sws cones were concentrated in dorso-temporal retina in the dunnart with a shallow dec ...200814570252
the effect of temperature on adrenergic receptors of alveolar type ii cells of a heterothermic marsupial.fat-tailed dunnarts, sminthopsis crassicaudata, survive dramatic changes in body temperature during torpor without experiencing surfactant dysfunction. adrenergic factors regulate surfactant secretion through beta(2)-adrenergic receptors on alveolar type ii cells. temperature has no effect on the secretory response of dunnart type ii cells to adrenergic stimulation. we hypothesise that during torpor, dunnart type ii cells up-regulate the number of adrenergic receptors present on type ii cells to ...200314550258
neurogenesis in the hippocampus of an adult the adult eutherian brain, stem cells in the dentate gyrus continually divide throughout adult life and into old age producing new granule cells. however, it was not known whether this is also the case for marsupials. previously, in fact, it was thought that marsupials did not have continued neurogenesis in the mature brain. here we examined neurogenesis in the adult brain of a small marsupial, the fat-tailed dunnart, using 3h-thymidine to label newly generated cells. we showed that neurogene ...200312907855
the parasympathetic nervous system: its role during torpor in the fat-tailed dunnart (sminthopsis crassicaudata).this study investigated the effect of parasympathetic inhibition on the cardio-ventilatory interaction during torpor in the fat-tailed dunnart (sminthopsis crassicaudata). studies on the influence of the autonomic nervous system on cardiac function during torpor have focused on deep hibernation in eutherians. s. crassicaudata was used as a representative of the metatheria that exhibits shallow, daily torpor as a comparison for the patterns of cardiac function found in other mammalian heterotherm ...200212444466
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