Artículos de revistas: "Sminthopsis crassicaudata"

1

Haynes, JI y GW Skidmore. "Hematology of the Dasyurid Marsupials Sminthopsis-Crassicaudata and Sminthopsis-Macroura". Australian Journal of Zoology 39, n.º 2 (1991): 157. http://dx.doi.org/10.1071/zo9910157.

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Various haematological parameters and morphological aspects were determined for blood collected from 52 fat-tailed dunnarts, Sminthopsis crassicaudata. Compared with those of other marsupials, the erythrocyte and leukocyte counts, haemoglobin concentration and packed cell volume were low, whereas the percentage of reticulocytes (8%) was high. Differential counts revealed a sexual dimorphism for the percentage of neutrophils and lymphocytes present. Blood cell counts, including reticulocyte and differential counts, were also performed on blood from 11 animals of a closely related species, Sminthopsis macroura. For both species mature and developing blood cells from circulating blood, bone marrow, and intestinal mucosa were examined with the light and transmission electron microscope. The unusual features of peripheral blood were: the band forms of neutrophils with annular nuclei; a high percentage of hypersegmented neutrophils; the persistence of polyribosomes in many circulating red blood cells which otherwise appeared mature; the lack of basophils; the absence of eosinophils in S. crassicaudata and the rarity of these leukocytes in S. macroura. The ultrastructure of the developing and circulating blood cells was similar to that previously described for humans, except for the later stages of nuclear maturation in some neutrophils. In these cells annular nuclei developed into rings of beads that then broke to give the typical lobulated nuclei of mature neutrophils. All three types of granulocytes were found in the bone marrow. The leukocytic granules appeared slightly different from their human counterparts.

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2

Cooper, S. J. B., M. Adams y A. Labrinidis. "Phylogeography of the Australian dunnart Sminthopsis crassicaudata (Marsupialia : Dasyuridae)". Australian Journal of Zoology 48, n.º 5 (2000): 461. http://dx.doi.org/10.1071/zo00014.

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Analyses of mitochondrial DNA (mtDNA) and allozymes are used to investigate the population genetic structure, phylogeography and systematics of the fat-tailed dunnart, Sminthopsis crassicaudata. Phylogenetic analyses of control region sequences reveal the presence of two major mtDNA haplotype clades. A survey of the distribution of the two clades using diagnostic restriction endonucleases shows that one clade is restricted to southeast Australia whereas the second clade occupies the remaining central to western range of S. crassicaudata. Allozyme electrophoresis also shows concordant patterns of population structure, with significant differences in allele frequency at three loci between populations in the southeast and northwest. Together, the mtDNA and allozyme data provide evidence that S. crassicaudata consists of two Evolutionarily Significant Units (ESUs). The distribution of each ESU is not concordant with the distribution of the subspecies of S. crassicaudata, and we propose that the current subspecies classification neither reflects the major genetic subdivisions present within S. crassicaudata nor would be appropriate for any future conservation management. The level of divergence between mtDNA clades (3.4%) is indicative of cladogenesis in the Pleistocene and reflects a long-term barrier to maternal gene flow between these two populations. One potential historical barrier was Lake Bungunnia, which persisted in the Murray basin over much of the Pleistocene.

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3

Read, DG. "Weather and Trap Response of the Dasyurid Marsupials Sminthopsis-Crassicaudata, Planigale-Gilesi and Planigale-Tenuirostris". Wildlife Research 15, n.º 2 (1988): 139. http://dx.doi.org/10.1071/wr9880139.

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Daily captures of Sminthopsis crassicaudata, Planigale gilesi and P. tenuirostris have been analysed with respect to weather variables in an arid environment. Numbers of S. crassicaudata caught in traps were not affected by changes in air pressure but more (P=0.01) P. gilesi and P. tenuirostris were trapped when the air pressure was increasing from a level below the monthly mean. Light rain increased the numbers of all species trapped (P=0.05) but moonlight had no effect. A canonical correlation analysis separated Sminthopsis from Planigale on the basis of responses to temperature and relative humidity variables. It is not clear if the trap responses of the dasyurids are directly related to the weather or other contemporary factors, particularly food availability. Results indicate that weather has a strong influence on the trap success of small mammal studies in arid Australia.

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4

STRACHAN, JESSICA, LING-YU E. CHANG, MATTHEW J. WAKEFIELD, JENNIFER A. MARSHALL GRAVES y SAMIR S. DEEB. "Cone visual pigments of the Australian marsupials, the stripe-faced and fat-tailed dunnarts: Sequence and inferred spectral properties". Visual Neuroscience 21, n.º 3 (mayo de 2004): 223–29. http://dx.doi.org/10.1017/s0952523804213281.

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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 have used evolutionarily conserved sequences of the cone pigments of other species, including the tammar wallaby, to design primers to amplify the S. macroura and S. crassicaudata pigment sequences by the polymerase chain reaction (PCR) using genomic DNA or retinal cDNA as a template. These primers will be useful for amplifying cone opsin coding sequences from a variety of vertebrates. Amplified products were directly sequenced to determine gene structure and coding sequences. The inferred amino acid sequences of the cone visual pigments indicated that both species have middle-wave-sensitive (MWS) pigments with a predicted absorption maximum (λmax) at 530 nm, and ultraviolet-sensitive (UVS) pigments with a predicted λmax at 360 nm. The MWS pigments of the two species differ by two, and UVS by three amino acid positions. No evidence was obtained for a third cone pigment in either species.

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5

Bishop, N., M. Bulbert, S. Carr, S. Kroker y J. Millikan. "Sonographic Analysis of Vocalisations in Captive Dunnarts, Sminthopsis crassicaudata." Australian Mammalogy 18, n.º 1 (1995): 99. http://dx.doi.org/10.1071/am95099.

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6

Nagy, KA, AK Lee, RW Martin y MR Fleming. "Field Metabolic-Rate and Food Requirement of a Small Dasyurid Marsupial, Sminthopsis-Crassicaudata". Australian Journal of Zoology 36, n.º 3 (1988): 293. http://dx.doi.org/10.1071/zo9880293.

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Field metabolic rates (FMRs) and rates of water flux in free-ranging fat-tailed dunnarts, Sminthopsis crassicaudata, were measured during spring (late October) using doubly labelled water. Feeding rates were estimated on the basis of water and energy fluxes. FMRs averaged 68.7 kJ d-' in adults (mean body mass= 16.6 g), and were 29.2 kJ d-' in juveniles (6.1 g). These FMRs are 6.6 times basal metabolic rate (BMR), and are much higher than the hypothetical maxima of four to five times BMR. Other dasyurid marsupials also have high FMR/BMR ratios, but so does a small petaurid marsupial. S. crassicaudata consumed 80-90% of its body mass in arthropods each day. The diet of arthropods apparently provided enough water for the animals to maintain water balance without drinking during this study.

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7

Brooker, BM, JE Oshea y T. Stewart. "Renal Vasculature of 2 Dasyurid Marsupials, Sminthopsis-Dolichura and S-Crassicaudata". Australian Journal of Zoology 43, n.º 3 (1995): 259. http://dx.doi.org/10.1071/zo9950259.

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The renal vasculature of two dasyurid marsupials, Sminthopsis dolichura and S. crassicaudata, was examined using scanning electron microscopy of vascular corrosion casts of the kidney. Each species had a pair of unipapillary kidneys and the structural organisation of the major renal arterial vessels was similar to that of other placental mammals. The glomerulus of both species consisted of a network of dividing and anastomosing capillary loops. The glomeruli varied markedly in size, shape and complexity. Some afferent arterioles extended back towards the renal medulla, positioning the glomeruli closer to the cortico-medullary border. This placement of glomeruli may extend the loop of the nephron further into the medulla and thereby enhance counter-current water reabsorption and the final urine concentration. In both S. crassicaudata and S. dolichura, a dense mesh of numerous fine capillaries lined the wall of the renal pelvis adjacent to the inner medulla, with a unique configuration in that they were aligned perpendicular to the vasa recta. The function of these fine capillaries is unknown.

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8

Read, DG. "Habitat Use by Sminthopsis-Crassicaudata, Planigale-Gilesi and Planigale-Tenuirostris (Marsupialia, Dasyuridae) in Semiarid New-South-Wales". Wildlife Research 14, n.º 4 (1987): 385. http://dx.doi.org/10.1071/wr9870385.

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Habitat use by Sminthopsis crassicaudata, Planigale gilesi and P. tenuirostris was investigated in the arid zone of New South Wales. All species showed considerable flexibility in habitat use at all times, and abundance was poorly predicted from easily measured parameters of the habitat. However, evidence was found for separation of microhabitat among these sympatric species. Multiple regression analysis indicated that abundance of S. crassicaudata was negatively associated with height of vegetation and the depth and density of soil cracks, and that of P. gilesi was positively associated with these habitat variables. Plant height was positively associated with abundance of P. tenuirostris and it was the only important predictor for this species. These results are discussed in conjunction with trapping records from other habitats.

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9

Rodger, JC, WG Breed y JH Bennett. "Gonadotrophin-induced oestrus and ovulation in the polyovulatory marsupial Sminthopsis crassicaudata". Reproduction, Fertility and Development 4, n.º 2 (1992): 145. http://dx.doi.org/10.1071/rd9920145.

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Sminthopsis crassicaudata is a small (approximately 16 g) polyovulatory dasyurid marsupial which has the potential to become an important model species. This study examined the use of exogenous hormone treatment to manipulate the breeding of S. crassicaudata and as a means to obtain timed developmental stages for further study. Two thirds (21/32) of the females treated with 1.0 or 5.0 I.U. of pregnant mare serum gonadotrophin (PMSG) had ovulated when the contents of their reproductive tracts were examined 5 or 6 days later. Only one of eight females treated with 0.2 I.U. PMSG had ovulated in the same period. Although a similar proportion of animals treated with 1.0 I.U. and 5.0 I.U. ovulated, the ovulation rate was significantly lower when the higher dose was administered (mean of 10.5 ovulations per female v. 3.8 ovulations per female). In addition, the ovaries of 6/8 of the animals treated with 5.0 I.U. PMSG had luteinized follicles with degenerating oocytes, evidence of over-stimulation. Follicular luteinization also occurred in 4/8 animals treated with 1 I.U. PMSG. Oocyte maturation and ovulation occurred following PMSG stimulation without injection of synthetic gonadotrophin releasing hormone (GnRH). Treatment with a 10-micrograms dose of GnRH following PMSG seemed to have no effect on the outcome. Of the females that had ovulated by Day 6, three quarters had mated and some had fertilized eggs and two-cell embryos in the oviducts and uteri. In a further series of experiments the subsequent development of embryos conceived after PMSG treatment was assessed. Two thirds of treated females mated within 7 days of treatment and 60% of these matings yielded embryos when examined 11 days after PMSG. However, full-term development was only achieved in one animal. Gonadotrophin treatment of S. crassicaudata thus may have application as a means to obtain mature or maturing oocytes, cleavage stage embryos and blastocysts, but at this stage it appears not to offer promise as a method to achieve full-term development.

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10

Hope, P. J., D. Pyle, C. B. Daniels, I. Chapman, M. Horowitz, J. E. Morley, P. Trayhurn, J. Kumaratilake y G. Wittert. "Identification of brown fat and mechanisms for energy balance in the marsupial, Sminthopsis crassicaudata". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 273, n.º 1 (1 de julio de 1997): R161—R167. http://dx.doi.org/10.1152/ajpregu.1997.273.1.r161.

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The presence of brown adipose tissue (BAT) in marsupials is controversial because attempts to identify mitochondrial uncoupling protein (UCP) have been unsuccessful. Sminthopsis crassicaudata is a small nocturnal marsupial with an interscapular pad of adipose tissue. Electron microscopy revealed this tissue to have characteristics typical of BAT. GDP binding and UCP detection by immunoblot confirmed BAT. Expression of UCP was increased by cold exposure. When animals were placed from 28 to 15 degrees C, body temperature (Tb) decreased by 1.7 degrees C within 30 min and a further 1.0 degree C by 90 min (P < 0.001) before stabilizing at these lower levels. When animals were returned to 28 degrees C, Tb increased within 30 min (P < 0.001) and returned to basal by 120 min. When animals were maintained at 15 degrees C with ad libitum food for 12 days, Tb (P < 0.05), tail width (P < 0.04), and O2 consumption (P < 0.01) all decreased. The respiratory quotient increased (P < 0.001), indicating a change from fat to carbohydrate utilization. Food intake was unchanged, and body weight increased on day 1 (P < 0.01) before returning to baseline on day 3, remaining stable thereafter. These data suggest that although BAT is present in the marsupial S. crassicaudata, it may not be necessary for thermogenesis, at least in the short term. S. crassicaudata utilizes a plasticity in Tb and a change in substrate utilization to maintain energy balance and body composition without the need for an increase in metabolic rate or food consumption and without the need for torpor.

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11

Clements, Fiona, Perdita Hope, Chris Daniels, Ian Chapman y Gary Wittert. "Thermogenesis in the marsupial Sminthopsis crassicaudata: effect of catecholamines and diet". Australian Journal of Zoology 46, n.º 4 (1998): 381. http://dx.doi.org/10.1071/zo98022.

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The fat-tailed dunnart (Sminthopsis crassicaudata) is a small carnivorous marsupial with detectable brown adipose tissue. In order to determine whether catecholamines and food intake increase thermogenesis in this species, we measured the response of oxygen consumption (Vo2) to (i) intraperitoneal noradrenaline (0.25–4.0 mg kg-1), and (ii) food intake. The effect of nutritional status and macronutrient composition of the diet on the Vo2 response to food intake was determined by feeding both non-deprived and 24-h-food-deprived animals with either laboratory diet (1.01 Kcal g-1 (4.2 KJ g-1), 20% fat) or live mealworms (Tenebrio molitor larvae) (2.99 Kcal g-1 (12.5 KJ g-1), 30% fat). Intraperitoneal injection of noradrenaline at doses of 0.25 and 0.5 mg kg-1 increased Vo2 by 14% and 31% respectively at 30 min (P ≤ 0.05), whereas noradrenaline at 2 and 4 mg kg-1 decreased Vo2 by 10% and 31% respectively (P ≤ 0.05). Following food intake, Vo2 increased in both non-deprived (P < 0.05) and 24-h-food-deprived (P < 0.05) animals. While the magnitude of the increase in Vo2 was similar in animals fed with either laboratory diet or mealworms, both diets increased Vo2 more in non-deprived than in 24-h-food-deprived animals (P < 0.05). These results suggest that in S. crassicaudata (i) catecholamines increase thermogenesis and (ii) the magnitude of diet-induced thermogenesis is dependent on both the nutritional status of the animal and the macronutrient composition of the diet.

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12

Vozzo, Rosalie, Gary A. Wittert, Ian M. Chapman, Robert Fraser, Perdita J. Hope, Michael Horowitz, Motaz M. Alshaher, Vijaya B. Kumar y John E. Morley. "Evidence that nitric oxide stimulates feeding in the marsupial Sminthopsis crassicaudata". Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology 123, n.º 2 (junio de 1999): 145–51. http://dx.doi.org/10.1016/s0742-8413(99)00022-5.

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13

RODGER, J., S. A. DUNLOP y L. D. BEAZLEY. "The ipsilateral retinal projection in the fat-tailed dunnart, Sminthopsis crassicaudata". Visual Neuroscience 15, n.º 4 (abril de 1998): 677–84. http://dx.doi.org/10.1017/s095252389815407x.

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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 medially to define a ventrolateral crescent. Temporal to the naso-temporal division, a mean of 77% of ganglion cells projected ipsilaterally; these cells represented 20% of the total ganglion cell population. The magnitude and retinal location of the ipsilateral projection correlated with the extensive binocular field which measured 180 deg in the vertical (from 20 deg below the horizontal axis to 70 deg beyond the zenith) and 140 deg in horizontal meridian. Ipsilaterally projecting axons were restricted to the lateral third of the optic nerve along its length, sharing territory with contralaterally projecting axons.

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14

Stannard, Hayley J., Bronwyn M. McAllan y Julie M. Old. "Dietary composition and nutritional outcomes in two marsupials,Sminthopsis macrouraandS. crassicaudata". Journal of Mammalogy 95, n.º 3 (26 de junio de 2014): 503–15. http://dx.doi.org/10.1644/13-mamm-a-071.

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15

Breed, W. G., C. M. Leigh, J. M. Washington y L. L. L. Soon. "Unusual nuclear structure of the spermatozoon in a marsupial,Sminthopsis crassicaudata". Molecular Reproduction and Development 37, n.º 1 (enero de 1994): 78–86. http://dx.doi.org/10.1002/mrd.1080370111.

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16

Warnecke, Lisa, Gerhard Körtner, Chris J. Burwell, James M. Turner y Fritz Geiser. "Short-term movement patterns and diet of small dasyurid marsupials in semiarid Australia". Australian Mammalogy 34, n.º 1 (2012): 49. http://dx.doi.org/10.1071/am10052.

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Since little information is available on the spatial ecology of small arid-zone marsupials, we used radio-tracking to investigate the small-scale activity patterns of three dasyurid species in semiarid Australia. Sminthopsis crassicaudata, Planigale gilesi and S. macroura were equipped with miniature radio-transmitters to monitor choice of resting sites and daily movements. Resting sites were located within an area of 1.27 ± 0.36 ha, 0.12 ± 0.02 ha and 3.60 ± 0.95 ha, respectively and individuals returned to previously used resting sites regularly. We also analysed scat samples of S. crassicaudata and P. gilesi, and identified Araneae, Hymenoptera and Orthoptera as the major prey taxa for both species. Our study presents the first radio-tracking-based information on movements for these species in semiarid habitat, which indicates that, over a period of several weeks, resting sites are situated within small and defined areas.

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17

Frey, H. "Energetic Significance of Torpor and Other Energy-Conserving Mechanisms in Free-Living Sminthopsis-Crassicaudata (Marsupialia, Dasyuridae)". Australian Journal of Zoology 39, n.º 6 (1991): 689. http://dx.doi.org/10.1071/zo9910689.

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Factors influencing the use of energy-conserving mechanisms including torpor, as well as their energetic significance, were studied in free-living Sminthopsis crassicaudata at Werribee (Victoria) during winter 1981 and 1982. Possible correlations between behavioural or physiological condition of captured animals and climatic variables or food availability were investigated. Daily energy expenditure was calculated by combining time-budget analysis in the field (based on radio-tracking) with respirometric measurements of metabolic rates in captivity. The energy-conserving mechanisms used were torpor, reduced activity, basking, huddling in groups, use of nests, choice of a thermally favourable resting site and slightly lowered resting body temperature. Torpor and reduced activity only occurred after cold (< 6-degrees-C) and dry nights, when surface activity of prey was very low, leaving S. crassicaudata in a negative energy balance. Rainy nights increased the availability of prey (particularly slugs and earthworms), and the animals did not enter torpor. During the non-breeding season (April-June), the energy savings [compared with a reference budget (E(r)) where no energy-conserving mechanism is used] reached 20-25% of E(r) after rainy or mild and dry nights, the major contributors being huddling and use of a nest. After cold dry nights, the savings may reach 40-50% of E(r), primarily due to torpor and reduced activity. Various energy-conserving mechanisms were used, even in the absence of short-term energetic problems, resulting in spontaneous energy savings and a reduced depletion of food. More prey was then available at the onset of breeding (mid-July), when energy requirements increase noticeably, because of smaller group size, smaller nests and energy channelled into offspring. The adpative value of spontaneous energy savings is discussed and the overwintering energetics of S. crassicaudata are compared with those of some European shrews.

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18

Godfrey, Gillian K. "Body-temperatures and torpor in Sminthopsis crassicaudata and S. larapinta (Marsupialia-Dasyuridae)". Journal of Zoology 156, n.º 4 (20 de agosto de 2009): 499–511. http://dx.doi.org/10.1111/j.1469-7998.1968.tb04367.x.

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19

Bonney, K. R. y C. D. L. Wynne. "Configural learning in two species of marsupial (Setonix brachyurus and Sminthopsis crassicaudata)." Journal of Comparative Psychology 117, n.º 2 (2003): 188–99. http://dx.doi.org/10.1037/0735-7036.117.2.188.

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20

Anderson, Rebecca y William G. Breed. "In vivo parthenogenetic activation of ovulated oocytes in a marsupial, Sminthopsis crassicaudata". Zygote 1, n.º 3 (agosto de 1993): 231–36. http://dx.doi.org/10.1017/s0967199400001519.

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SummaryThe occurrence of in vivo parthenogenesis is documented for laboratory-bred individuals of the Australian dasyurid marsupial, Sminthopsis crassicaudata. About 30% of females that had been isolated from males for a greater period of time than the length of pregnancy were found, on dissection of their uteri, to have embryos present. The embryos were surrounded by a mucoid coat and shell membrane and at least the first two cleavage divisions occurred normally. After this time, however, unequal cleavage divisions appeared to result. The parthenogenesis that takes place may be initiated as a result of activation of ageing ovulated oocytes. Its frequent occurrence may prove useful in a study of maternal and paternal contributions to early embryonic development in this species.

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21

Holloway, Joanne C. y Fritz Geiser. "Reproductive status and torpor of the marsupial Sminthopsis crassicaudata: Effect of photoperiod". Journal of Thermal Biology 21, n.º 5-6 (octubre de 1996): 373–80. http://dx.doi.org/10.1016/s0306-4565(96)00023-x.

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22

Hope, R. M., J. H. Bennett y C. M. Chesson. "Genetic variation in natural and laboratory populations of the marsupial Sminthopsis crassicaudata". Biochemical Genetics 24, n.º 7-8 (agosto de 1986): 597–613. http://dx.doi.org/10.1007/bf00504337.

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23

Laird, Melanie K., Michaela Turancova, Bronwyn M. McAllan, Christopher R. Murphy y Michael B. Thompson. "Uterine focal adhesion dynamics during pregnancy in a marsupial (Sminthopsis crassicaudata ; Dasyuridae)". Anatomical Record 300, n.º 6 (7 de febrero de 2017): 1150–59. http://dx.doi.org/10.1002/ar.23535.

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24

Laird, Melanie K., Michael B. Thompson, Christopher R. Murphy y Bronwyn M. McAllan. "Uterine epithelial cell changes during pregnancy in a marsupial (Sminthopsis crassicaudata; Dasyuridae)". Journal of Morphology 275, n.º 10 (16 de abril de 2014): 1081–92. http://dx.doi.org/10.1002/jmor.20282.

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25

Calver, MC, DR King, JS Bradley, JL Gardner y G. Martin. "An Assessment of the Potential Target Specificity of 1080 Predator Baiting in Western-Australia". Wildlife Research 16, n.º 6 (1989): 625. http://dx.doi.org/10.1071/wr9890625.

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The potential hazard of 1080 baiting for predators to 14 species of non-target mammals in the pastoral areas of Western Australia and a further six from Western Australia's Fitzgerald River National Park, was assessed by comparing projected doses of 1080 (based on consumption of non-toxic bait by captive animals in the absence of alternative food) with the approximate lethal dose of 1080 for each species. These figures suggested that individuals from 12 species were potentially at risk from crackle baits, while only individuals from Dasyurus hallucatus, Ningaui spp., Sminthopsis crassicaudata, Planigale maculata, one population of Leggadina forresti and one population of Sminthopsis ooldea were potentially endangered by meat baits. Tests using the native mammals Zyzomys argurus and Pseudomys hermannsbergensis and laboratory mice (Mus musculus) and laboratory rats (Rattus norvegicus) showed that individuals of all species reduced their consumption of toxic bait relative to non-toxic bait, although this did not prevent three of five rats and one of three P. hermannsbergensis from being killed.

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26

Bennett, JH, WG Breed, DL Hayman y RM Hope. "Reproductive and Genetic-Studies With a Laboratory Colony of the Dasyurid Marsupial Sminthopsis-Crassicaudata". Australian Journal of Zoology 37, n.º 3 (1989): 207. http://dx.doi.org/10.1071/zo9890207.

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The fat-tailed dunnart, Sminthopsis crassicaudata, is a small insectivorous dasyurid (adult weight about 16 g) widely distributed in Australia. A laboratory colony of this marsupial, which has been built up over many years, is providing material for studies of dasyurid reproductive biology and genetics. In the area of reproductive biology, we have found a marked disparity in the age of maturation between the two sexes, and we are currently studying certain aspects of spermatogenesis, sperm transport, fertilisation and early embryonic development. Genetical studies have revealed large differences between the sexes in autosomal linkage values and meiotic chromosome behaviour. In females, we have observed very limited intrachromosomal recombination and this is reflected in the distal localisation of chiasmata on the autosomes. Extreme localisation of chiasmata has not hitherto been found in a mammal, and it will be interesting to see how widely it occurs in other marsupial species. The genetical and cytological findings lead to a number of predictions that are being tested in further experimental work with the colony. Although we have been able to raise litter production to a high level, the very variable and unpredictable nature of male reproductive performance currently limits the wider use of the S. crassicaudata colony. It is clear, however, that this dasyurid has the potential to become a very useful laboratory marsupial and that it will be especially valuable for comparative biomedical studies.

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27

Czarny, N. A. y J. C. Rodger. "The spermatozoa of the dasyurid marsupial, Sminthopsis crassicaudata, are highly susceptible to cold shock". Reproduction, Fertility and Development 22, n.º 3 (2010): 580. http://dx.doi.org/10.1071/rd09119.

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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°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 effect. Spermatozoa that were rapidly cooled to 4°C maintained only 2% motility when re-warmed but the addition of at least 10% egg yolk was beneficial and upon re-warming greater than 65% of the initial motility was maintained. In order to achieve motile spermatozoa at 0°C, controlled-rate cooling at 0.5°C min–1 was examined. In the absence of egg yolk there was a significant decline in the percentage of motile spermatozoa below 4°C. However, the inclusion of at least 10% egg yolk resulted in no loss of motility in spermatozoa cooled to 0°C. This is the first experimental study indicating that spermatozoa from a marsupial are highly susceptible to cold shock and that the impact of rapid chilling can be mitigated by the addition of 10% egg yolk. The ability to successfully cool the spermatozoa of S. crassicaudata to 0°C may have an important role in future studies examining dasyurid sperm cryopreservation.

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28

Bonney, Kathryn R. y C. D. L. Wynne. "Visual discrimination learning and strategy behavior in the fat-tailed dunnarts ( Sminthopsis crassicaudata )." Journal of Comparative Psychology 116, n.º 1 (2002): 55–62. http://dx.doi.org/10.1037/0735-7036.116.1.55.

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29

Hope, P. "Decreased Glucose Utilisation Does Not Increase Food Intake in the Marsupial Sminthopsis crassicaudata". Physiology & Behavior 63, n.º 1 (31 de diciembre de 1997): 31–34. http://dx.doi.org/10.1016/s0031-9384(97)00383-1.

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30

Langman, C., S. Orgeig y C. B. Daniels. "Alterations in composition and function of surfactant associated with torpor in Sminthopsis crassicaudata". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 271, n.º 2 (1 de agosto de 1996): R437—R445. http://dx.doi.org/10.1152/ajpregu.1996.271.2.r437.

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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 after 1,4 or 8 h of torpor (Tb < 20 degrees C). Lung compliance was measured before and after the removal of surfactant, and tissue compliance was determined by inflating the lung with saline. Relative to total phospholipid (PL), mouse surfactant contained proportionately less phosphatidylinositol but more cholesterol (Chol) and phosphatidylglycerol than that of the dunnart. Lung compliance was lower in dunnarts than in mice, consistent with an allometric effect. Surfactant levels, including total PL, Chol, and disaturated phospholipid (DSP) increased during torpor. The relative proportions of Chol and DSP increased after 4 and 8 h, respectively. In marked contrast to previous studies on the behavior of isolated lungs from homeothermic mammals, in our study the lung compliance of dunnarts remained unchanged throughout torpor. Tissue compliance decreased at 1 and 4 h of torpor, but this decrease was abolished by 8 h. It appears that the surfactant of the dunnarts counteracted the negative effect of tissue compliance at 1 and 4 h, an effect not present in homeothermic mammals. However, because lung compliance was maintained at 1 h of torpor in the absence of a compositional change in surfactant lipids, the changes in lipid composition observed at 4 and 8 h of torpor are thought to relate to functions of surfactant other than that of maintaining lung compliance.

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31

Holloway, J. C. y F. Geiser. "Influence of torpor on daily energy expenditure of the dasyurid marsupial Sminthopsis crassicaudata". Comparative Biochemistry and Physiology Part A: Physiology 112, n.º 1 (septiembre de 1995): 59–66. http://dx.doi.org/10.1016/0300-9629(95)00089-p.

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32

Zosky, G. R. y J. E. O'Shea. "The cardiac innervation of a marsupial heterotherm, the fat-tailed dunnart (Sminthopsis crassicaudata)". Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology 173, n.º 4 (1 de junio de 2003): 293–300. http://dx.doi.org/10.1007/s00360-003-0335-y.

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33

Hope, P. J., G. A. Wittert, M. Horowitz y J. E. Morley. "Feeding patterns of S. crassicaudata (Marsupialia:Dasyuridae): role of gender, photoperiod, and fat stores". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 272, n.º 1 (1 de enero de 1997): R78—R83. http://dx.doi.org/10.1152/ajpregu.1997.272.1.r78.

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Little is known about feeding regulation in marsupials. Sminthopsis crassicaudata is a small nocturnal marsupial, whose tail contains approximately 25% total body fat. We have characterized the effect of gender, photoperiod, food deprivation, and tail removal (lipectomy) on food intake in S. crassicaudata. Males and females maintained in captivity on long-day (LD, 16:8-h light-dark cycle) and short-day (SD, 9:15-h light-dark cycle) light regimens were studied. Feeding patterns under LD and SD photoperiods were initially measured under conditions of ad libitum food supply and then in groups of animals exposed to 24- and 36-h periods of food deprivation. Feeding occurred predominantly in the dark. Females maintained on SD photoperiods for 5 wk ate less (P < 0.005) than females on LD or males on either SD or LD, but this reduction in food intake was not associated with a decrease either in body weight or tail width. After both 24- and 36-h fasts, total food intake in the subsequent 24 h increased (P < 0.001) up to 100% in all groups, with no gender or photoperiod effect. SD females, however, ate less (P < 0.05) than LD females in the first 6 h after refeeding. Tail width decreased (P < 0.05) in all groups of animals after the 36-h fast but only in LD animals after the 24-h fast (P < 0.05). Body weight decreased similarly in all groups of animals after fasting. The effect of tail removal was studied in LD males. The procedure, which was well tolerated, resulted in an initial decrease in body weight (P < 0.005), which recovered within 3 wk. On day 45 in the animals whose tails were removed, body fat was approximately 30% greater than body fat of controls (P < 0.02). No significant increase in food intake occurred after tail removal. These data demonstrate in Sminthopsis crassicaudata 1) a photoperiod and gender-dependent effect on food intake, 2) the ability to regulate the amount and distribution of total body fat, and 3) a dissociation between the regulation of food intake and changes in body fat stores, which suggest alterations in energy expenditure.

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34

Hope, Perdita J., Ian Chapman, John E. Morley, Michael Horowitz y Gary A. Wittert. "Effect of diet on the response to leptin in the marsupialSminthopsis crassicaudata". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 276, n.º 2 (1 de febrero de 1999): R373—R381. http://dx.doi.org/10.1152/ajpregu.1999.276.2.r373.

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The aim of this study was to determine in the marsupial Sminthopsis crassicaudata 1) the effect of leptin on food intake, body fat stores, and metabolism and 2) whether leptin can prevent a diet-induced increase in adiposity. In response to 21 days of feeding with mealworms (2.99 kcal/g, 30% fat), body weight ( P < 0.0001) and tail width ( P < 0.0001) increased, compared with control animals fed with laboratory diet (1.01 kcal/g, 20% fat). Subsequently, S. crassicaudata were randomly allocated to receive either laboratory diet or a choice between laboratory diet and mealworms. For 13 days, one-half of the animals in each dietary group received intraperitoneal human leptin (2.5 mg/kg twice daily), while the other one-half received phosphate-buffered saline. In animals receiving laboratory diet alone, leptin induced a decrease in body weight ( P < 0.0001), tail width ( P < 0.0001), and energy intake ( P < 0.01). In animals receiving both laboratory diet and mealworms, leptin had no effect on body weight or tail width, although the proportion of laboratory diet eaten was reduced ( P = 0.0001), and there was a nonsignificant fall in overall energy intake ( P = 0.07). We conclude that in S. crassicaudata, 1) a high-calorie, higher-fat diet induces an increase in adiposity and 2) leptin induces weight loss, but 3) an increase in dietary calories and fat content is associated with resistance to the actions of leptin.

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35

Roberts, CT y WG Breed. "Variation in ultrastructure of mucoid coat and shell membrane secretion of a dasyurid marsupial". Reproduction, Fertility and Development 8, n.º 4 (1996): 645. http://dx.doi.org/10.1071/rd9960645.

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In the dasyurid marsupial Sminthopsis crassicaudata, the shell membrane of cleaving embryos has a compact granular structure but becomes fibrous around blastocysts. Polyclonal antibodies were raised against the extracellular coats, mucoid and shell membrane, of oocytes and early embryos. Immunogold cytochemistry resulted in labelling of secretory granules in the epithelia of both the ampulla and isthmus of the oviduct, although the secretory granules of these two regions differed in their ultrastructural appearance. Those in the ampulla were heterogeneous with areas of varying electron density, whereas those in the isthmus were electron dense and homogeneous. Shell membrane precursors were found in secretory granules in the epithelia of the uterotubal junction and endometrial glands and were electron lucent.

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36

Czarny, N. A. y J. C. Rodger. "143. THE FIRST EVIDENCE OF HIGH SUSCEPTIBILITY TO COLD SHOCK BY THE SPERMATOZOA OF A MARSUPIAL, THE FAT TAILED DUNNART (SMINTHOPSIS CRASSICAUDATA)". Reproduction, Fertility and Development 21, n.º 9 (2009): 61. http://dx.doi.org/10.1071/srb09abs143.

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Carnivorous marsupials are native Australian predators including the highly threatened northern quoll (Dasyurus hallucatus) and Tasmanian devil (Sarcophilus harrisii). These species are currently actively managed in captive populations but assisted reproductive techniques such as gamete banking may also contribute to their conservation. Previous studies on a model dasyurid, the fat tailed dunnart (Sminthopsis crassicaudata), have found that spermatozoa do not survive freezing and thawing using a variety of freezing protocols and cryoprotectants. We have re-examined cold shock to investigate problems with sperm cryopreservation in S. crassicaudata. Epididymal spermatozoa were rapidly cooled to 0.5ºC in a pre-cooled tube held in an iced water slurry and upon re-warming the spermatozoa were non-motile (n=6). The addition of up to 20% egg yolk, which is considered protective to the spermatozoa of cold shock sensitive eutherians, did not improve the outcome (n=6). Similarly when S. crassicaudata spermatozoa were rapidly cooled to 4ºC, just 2% remained motile upon re-warming (n=10). However when spermatozoa were combined with at least 10% egg yolk and rapidly cooled to 4ºC only small reductions in motility were observed upon rewarming (n≥8). In order to achieve motile spermatozoa at 0ºC, controlled rate cooling at 0.5ºC/minute was examined. In the absence of egg yolk there was a decline in the percentage of motile spermatozoa below 4ºC (n=6). However if spermatozoa were combined with at least 10% egg yolk there was no significant loss of motility at temperatures as low as 0ºC (n=6). This study has revealed that at least one species of marsupial is highly susceptible to cold shock. These paradigm shifting findings give direction to future experiments aiming to develop a robust technique for sperm preservation in endangered dasyurids.

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37

Lopatko, Olga V., Sandra Orgeig, Christopher B. Daniels y David Palmer. "Alterations in the surface properties of lung surfactant in the torpid marsupial Sminthopsis crassicaudata". Journal of Applied Physiology 84, n.º 1 (1 de enero de 1998): 146–56. http://dx.doi.org/10.1152/jappl.1998.84.1.146.

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Lopatko, Olga V., Sandra Orgeig, Christopher B. Daniels, and David Palmer. Alterations in the surface properties of lung surfactant in the torpid marsupial Sminthopsis crassicaudata. J. Appl. Physiol. 84(1): 146–156, 1998.—Torpor changes the composition of pulmonary surfactant (PS) in the dunnart Sminthopsis crassicaudata [C. Langman, S. Orgeig, and C. B. Daniels. Am. J. Physiol. 271 ( Regulatory Integrative Comp. Physiol. 40): R437–R445, 1996]. Here we investigated the surface activity of PS in vitro. Five micrograms of phospholipid per centimeter squared surface area of whole lavage (from mice or from warm-active, 4-, or 8-h torpid dunnarts) were applied dropwise onto the subphase of a Wilhelmy-Langmuir balance at 20°C and stabilized for 20 min. After 4 h of torpor, the adsorption rate increased, and equilibrium surface tension (STeq), minimal surface tension (STmin), and the %area compression required to achieve STmin decreased, compared with the warm-active group. After 8 h of torpor, STmin decreased [from 5.2 ± 0.3 to 4.1 ± 0.3 (SE) mN/m]; %area compression required to achieve STmindecreased (from 43.4 ± 1.0 to 27.4 ± 0.8); the rate of adsorption decreased; and STeqincreased (from 26.3 ± 0.5 to 38.6 ± 1.3 mN/m). ST-area isotherms of warm-active dunnarts and mice at 20°C had a shoulder on compression and a plateau on expansion. These disappeared on the isotherms of torpid dunnarts. Samples of whole lavage (from warm-active and 8-h torpor groups) containing 100 μg phospholipid/ml were studied by using a captive-bubble surfactometer at 37°C. After 8 h of torpor, STmin increased (from 6.4 ± 0.3 to 9.1 ± 0.3 mN/m) and %area compression decreased in the 2nd (from 88.6 ± 1.7 to 82.1 ± 2.0) and 3rd (from 89.1 ± 0.8 to 84.9 ± 1.8) compression-expansion cycles, compared with warm-active dunnarts. ST-area isotherms of warm-active dunnarts at 37°C did not have a shoulder on compression. This shoulder appeared on the isotherms of torpid dunnarts. In conclusion, there is a strong correlation between in vitro changes in surface activity and in vivo changes in lipid composition of PS during torpor, although static lung compliance remained unchanged (see Langman et al. cited above). Surfactant from torpid animals is more active at 20°C and less active at 37°C than that of warm-active animals, which may represent a respiratory adaptation to low body temperatures of torpid dunnarts.

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38

Hope, R. M. "Genetic variation of tetrazolium oxidase in the fat-tailed dunnart Sminthopsis crassicaudata Gould (Marsupialia)". Animal Blood Groups and Biochemical Genetics 3, n.º 2 (24 de abril de 2009): 95–99. http://dx.doi.org/10.1111/j.1365-2052.1972.tb01237.x.

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39

Lopatko, Olga V., Sandra Orgeig, David Palmer, Samuel Schürch y Christopher B. Daniels. "Alterations in pulmonary surfactant after rapid arousal from torpor in the marsupial Sminthopsis crassicaudata". Journal of Applied Physiology 86, n.º 6 (1 de junio de 1999): 1959–70. http://dx.doi.org/10.1152/jappl.1999.86.6.1959.

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Torpor in the dunnart, Sminthopsis crassicaudata, alters surfactant lipid composition and surface activity. Here we investigated changes in surfactant composition and surface activity over 1 h after rapid arousal from torpor (15–30°C at 1°C/min). We measured total phospholipid (PL), disaturated PL (DSP), and cholesterol (Chol) content of surfactant lavage and surface activity (measured at both 15 and 37°C in the captive bubble surfactometer). Immediately after arousal, Chol decreased (from 4.1 ± 0.05 to 2.8 ± 0.3 mg/g dry lung) and reached warm-active levels by 60 min after arousal. The Chol/DSP and Chol/PL ratios both decreased to warm-active levels 5 min after arousal because PL, DSP, and the DSP/PL ratio remained elevated over the 60 min after arousal. Minimal surface tension and film compressibility at 17 mN/m at 37°C both decreased 5 min after arousal, correlating with rapid changes in surfactant Chol. Therefore, changes in lipids matched changes in surface activity during the postarousal period.

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40

Holland, Robert A. B., Susan J. Calvert, Rory M. Hope y Clive M. Chesson. "Blood O2 transport in newborn and adult of a very small marsupial (Sminthopsis crassicaudata)". Respiration Physiology 98, n.º 1 (septiembre de 1994): 69–81. http://dx.doi.org/10.1016/0034-5687(94)90037-x.

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41

Polymeropoulos, E. T., M. Jastroch y P. B. Frappell. "Absence of adaptive nonshivering thermogenesis in a marsupial, the fat-tailed dunnart (Sminthopsis crassicaudata)". Journal of Comparative Physiology B 182, n.º 3 (16 de octubre de 2011): 393–401. http://dx.doi.org/10.1007/s00360-011-0623-x.

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42

Hope, RM y GK Godfrey. "Genetically-Determined Variation of Pelage Color and Reflectance in Natural and Laboratory Populations of the Marsupial Sminthopsis-Crassicaudata (Gould)". Australian Journal of Zoology 36, n.º 4 (1988): 441. http://dx.doi.org/10.1071/zo9880441.

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A study of variation in dorsal pelage colour and reflectance of the dasyurid marsupial, Sminthopsis crassicaudata, has been based on animals captured from widely scattered areas in south-central Australia, and on a laboratory colony of this species. Measurements on the degree of resemblance between relatives gave heritability estimates of pelage reflectance close to the theoretical upper limit of unity. Measurements on the reflectance of animals captured from the wild revealed a geographical cline, with reflectance decreasing (animals becoming darker) with increasing southerly latitude. The higher reflectance (paler coloured) animals were found to inhabit the northern desert areas. We suggest that this cline results from a selective advantage enjoyed by animals whose dorsal pelage colour makes them relatively inconspicuous in their habitat to nocturnal preditors.

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43

Jastroch, M., K. W. Withers, S. Taudien, P. B. Frappell, M. Helwig, T. Fromme, V. Hirschberg et al. "Marsupial uncoupling protein 1 sheds light on the evolution of mammalian nonshivering thermogenesis". Physiological Genomics 32, n.º 2 (enero de 2008): 161–69. http://dx.doi.org/10.1152/physiolgenomics.00183.2007.

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Brown adipose tissue expressing uncoupling protein 1 (UCP1) is responsible for adaptive nonshivering thermogenesis giving eutherian mammals crucial advantage to survive the cold. The emergence of this thermogenic organ during mammalian evolution remained unknown as the identification of UCP1 in marsupials failed so far. Here, we unequivocally identify the marsupial UCP1 ortholog in a genomic library of Monodelphis domestica. In South American and Australian marsupials, UCP1 is exclusively expressed in distinct adipose tissue sites and appears to be recruited by cold exposure in the smallest species under investigation ( Sminthopsis crassicaudata). Our data suggest that an archetypal brown adipose tissue was present at least 150 million yr ago allowing early mammals to produce endogenous heat in the cold, without dependence on shivering and locomotor activity.

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44

Garrett, Andrew, Virginia Lannigan, Nathanael J. Yates, Jennifer Rodger y Wilhelmina Mulders. "Physiological and anatomical investigation of the auditory brainstem in the Fat-tailed dunnart (Sminthopsis crassicaudata)". PeerJ 7 (30 de septiembre de 2019): e7773. http://dx.doi.org/10.7717/peerj.7773.

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The fat-tailed dunnart (Sminthopsis crassicaudata) is a small (10–20 g) native marsupial endemic to the south west of Western Australia. Currently little is known about the auditory capabilities of the dunnart, and of marsupials in general. Consequently, this study sought to investigate several electrophysiological and anatomical properties of the dunnart auditory system. Auditory brainstem responses (ABR) were recorded to brief (5 ms) tone pips at a range of frequencies (4–47.5 kHz) and intensities to determine auditory brainstem thresholds. The dunnart ABR displayed multiple distinct peaks at all test frequencies, similar to other mammalian species. ABR showed the dunnart is most sensitive to higher frequencies increasing up to 47.5 kHz. Morphological observations (Nissl stain) revealed that the auditory structures thought to contribute to the first peaks of the ABR were all distinguishable in the dunnart. Structures identified include the dorsal and ventral subdivisions of the cochlear nucleus, including a cochlear nerve root nucleus as well as several distinct nuclei in the superior olivary complex, such as the medial nucleus of the trapezoid body, lateral superior olive and medial superior olive. This study is the first to show functional and anatomical aspects of the lower part of the auditory system in the Fat-tailed dunnart.

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45

Cooper, S. J. y R. M. Hope. "Evolution and expression of a beta-like globin gene of the Australian marsupial Sminthopsis crassicaudata." Proceedings of the National Academy of Sciences 90, n.º 24 (15 de diciembre de 1993): 11777–81. http://dx.doi.org/10.1073/pnas.90.24.11777.

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46

Ewer, R. F. "A Preliminary Survey of the Behaviour in Captivity of the Dasyurid Marsupial, Sminthopsis crassicaudata (Gould)". Zeitschrift für Tierpsychologie 25, n.º 3 (26 de abril de 2010): 319–65. http://dx.doi.org/10.1111/j.1439-0310.1968.tb00019.x.

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47

Pires, Susana S., Julia Shand, James Bellingham, Catherine Arrese, Michael Turton, Stuart Peirson, Russell G. Foster y Stephanie Halford. "Isolation and characterization of melanopsin ( Opn4 ) from the Australian marsupial Sminthopsis crassicaudata (fat-tailed dunnart)". Proceedings of the Royal Society B: Biological Sciences 274, n.º 1627 (4 de septiembre de 2007): 2791–99. http://dx.doi.org/10.1098/rspb.2007.0976.

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48

Leigh, Chris M. y Nalini Edwin. "An immunocytochemical study of the endocrine pancreas in the Australian fat-tailed dunnart (Sminthopsis crassicaudata)". Cell and Tissue Research 263, n.º 1 (enero de 1991): 195–98. http://dx.doi.org/10.1007/bf00318415.

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49

G., Zosky. "The parasympathetic nervous system: its role during torpor in the fat-tailed dunnart ( Sminthopsis crassicaudata )". Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology 172, n.º 8 (1 de diciembre de 2002): 677–84. http://dx.doi.org/10.1007/s00360-002-0295-7.

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50

Wittert, Gary A., Helen Turnbull, Perdita Hope, John E. Morley y Michael Horowitz. "Leptin prevents obesity induced by a high-fat diet after diet-induced weight loss in the marsupial S. crassicaudata". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 286, n.º 4 (abril de 2004): R734—R739. http://dx.doi.org/10.1152/ajpregu.00240.2003.

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The aims of this study were to determine in the marsupial Sminthopsis crassicaudata, the effects of leptin on food intake, body weight, tail width (a reflection of fat stores), and leptin mRNA, after caloric restriction followed by refeeding ad libitum with either a standard or high-fat preferred diet. S. crassicaudata ( n = 32), were fed standard laboratory diet (LabD; 1.01 kcal/g, 20% fat) ad libitum for 3 days. On days 4-10, animals received LabD at 75% of basal intake and then ( days 11-25) were fed either LabD or a choice of LabD and mealworms (MW; 2.99 kcal/g, 30% fat); during this time, half the animals ( n = 8) in each group received either leptin (2.5 mg/kg) or PBS intraperitoneally two times daily. On day 26, animals were killed and fat was removed for assay of leptin mRNA. At baseline, body weight, tail width, and food intake were similar in each group. After caloric restriction, body weight ( P < 0.001) and tail width ( P < 0.001) decreased. On return to ad libitum feeding in the PBS-treated animals, body weight and tail width returned to baseline in the LabD-fed animals ( P < 0.001) and increased above baseline in the MW-fed animals ( P < 0.001). In the LabD groups, tail width ( P < 0.001) and body weight ( P < 0.001) decreased after leptin compared with PBS. In the MW groups, the increase in tail width ( P < 0.001) and body weight ( P = 0.001) were attenuated after leptin compared with PBS. The expression of leptin mRNA in groups fed MW were greater in PBS than in leptin-treated animals ( P < 0.05). Therefore, after diet-induced weight loss, leptin prevents a gain in fat mass in S. crassicaudata; this has potential implications for the therapeutic use of leptin.

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