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At least 73 records · Page 4Linked to original sources
PubMed1986

A malignant mixed salivary tumour and a mammary carcinoma in a young wild eastern spotted native cat Dasyurus viverrinus (Marsupialia).

This report contains the first description of a salivary gland tumour in a dasyurid marsupial; the same animal also had a mammary carcinoma. All the previously described neoplasms have been in animals held in captivity for varying periods of time, whereas the case reported here was a young animal trapped in the wild and killed three days later. The development of tumours in the natural environment is important aetiologically.

Adenoma, Pleomorphic↗
PubMed1995

Body temperature rhythms and activity in reproductive Antechinus (Marsupialia).

To determine whether locomotor activity and body temperature (Tb) rhythms change during the mating season of male Antechinus stuartii and whether that could contribute to postmating die-off, we measured both variables in individuals kept in the laboratory under natural photoperiod. Before the mating season Antechinus were mainly nocturnal. However, during the mating period (end of August) males showed a markedly elevated activity level and some animals extended their activity period well into the light phase. After about 2 weeks, normal activity patterns were restored. Activity was always accompanied by elevated TbS, whereas resting phases were characterized by low TbS. During the mating season the average daily Tb was increased because animals maintained high TbS for longer time periods and because the resting Tb was also elevated. The rise of both Tb and locomotor activity during the mating season indicate an enhanced energy expenditure even when agonistic encounters between males and mating are excluded. However, under laboratory conditions without severe cold stress, food ad lib, and without social interaction males were able to avert postmating die-off.

Agonistic Behavior↗
PubMed1994

Behavioral and endocrinological correlates of social status in the male sugar glider (Petaurus breviceps Marsupialia: Petauridae).

Socially dominant male sugar gliders are heavier than socially subordinate males, have higher plasma testosterone and lower cortisol concentrations, win more social encounters, scan the arena more, scent-mark more, and are more active and move more quickly, even though they spend more time in the colony nesting box. When they are transferred into a foreign stable colony there is an impressive reversal of behavioral measures and a concomitant decrease in concentration of plasma testosterone and rise in cortisol that is apparent over the first 3 weeks of observation.

Animals↗
PubMed1984

Immunology of pouch young marsupials. I. Levels of immunoglobulin transferrin and albumin in the blood and milk of euros and wallaroos (hill kangaroos: Macropus robustus, marsupialia).

The concentration of total protein, albumin, transferrin, and immunoglobulin G of adult serum, pouch young serum, milk whey and colostrum has been estimated in three species of kangaroos, Macropus robustus, Macropus rufus (= Megaleia rufa) and Macropus giganteus. No study of this kind has previously been published for any marsupial species. The three individual proteins were antigenically identical in all four kinds of fluid. Colostrum and milk whey are relatively enriched in transferrin but have low levels of immunoglobulin G. Serum concentrations of total protein, albumin and transferrin rise steadily throughout pouch life and attain adult values when the young finally leaves the pouch. Serum concentrations of immunoglobulin G are very low for the first 90-100 days of pouch life, being approximately half of those in milk whey for this period. After this the level rises rapidly and also reaches adult values when the young leaves the pouch. We suggest that in the first 90-100 days the pouch young is largely protected humorally by passive immunity acquired from the mother, and after this it increasingly makes its own responses.

Age Factors↗
PubMed1986

Comparative red blood cell metabolism in three wallaby species, Macropus eugenii, Macropus parma and Thylogale thetis (Macropodidae: Marsupialia).

Aspects of red blood cell metabolism were compared among three species of small macropodid marsupials from different habitats. Packed cell volume (PCV), erythrocyte reduced glutathione (GSH) concentration and GSH regeneration rates were similar in all three species. The Parma wallaby had very low red cell potassium levels compared to the other species studied. The Tammar wallaby had higher rates of glucose consumption and lactate production in vitro at both pH 7.4 and 8.2 than did the Parma and significantly lower adenosine triphosphate (ATP) levels than the other species. These findings are consistent with preliminary reports published previously. The differences noted cannot be directly related to differences in the habitats of the species.

Adenosine Triphosphate↗
PubMed1988

Comparative lactation in two species of rat-kangaroo (Marsupialia).

1. Milk composition and energy content was measured in two related marsupials, Bettongia gaimardi and Potorous tridactylus. 2. Although protein content was consistently higher in bettong milk, lactational trends in both species are similar to those reported for other marsupials. 3. The faster relative growth rate of the bettong may be correlated with the increased protein and a higher milk intake.

Animals↗
PubMed1989

Milk composition in the red-necked wallaby, Macropus rufogriseus banksianus (Marsupialia).

1. Milk samples were collected throughout lactation from 10 captive red-necked wallabies. 2. The milk solids content increased throughout lactation and was accompanied by major changes in the relative proportions of protein, lipid and carbohydrate. 3. The carbohydrate fraction consisted of oligosaccharides in the first half of lactation but changed subsequently to monosaccharides. 4. The quantitative and qualitative changes observed were similar to those recorded for other macropodids.

Animals↗
PubMed1987

Changes in milk carbohydrates during lactation in the eastern quoll, Dasyurus viverrinus (Marsupialia).

1. Milk samples were obtained at various stages of lactation from 16 captive eastern quolls. 2. The mean milk carbohydrate concentration was 7.4% (w/v; total hexose) at 8 weeks post partum, decreasing to 5.2% at 17 weeks and to less than 2% at the end of lactation. 3. The predominant monosaccharide constituent of the carbohydrates was galactose, followed by glucosamine, glucose and sialic acid. 4. Thin layer and gel chromatography showed that the milk carbohydrates consisted of lactose and a variety of higher oligosaccharides, some of which appeared to be identical to oligosaccharides of known structure previously isolated from milk of the tammar wallaby, Macropus eugenii. 5. In general, both the quantitative and qualitative changes observed in the milk carbohydrates of the eastern quoll were similar to those documented for macropodids.

Animals↗
PubMed1990

Failure of glucocorticoid feedback during breeding in the male red-tailed phascogale Phascogale calura (Marsupialia: Dasyuridae).

An investigation was made into the factors which lead to an elevation in plasma free cortisol concentration during the last weeks of life of males in natural populations of the red-tailed phascogale Phascogale calura. The dexamethasone suppression-test was employed to examine the glucocorticoid feedback control of plasma cortisol both before and during the breeding season. In both sexes ACTH alone or in combination with dexamethasone caused an elevation in the plasma concentration of cortisol, corticosterone and free cortisol. Dexamethasone administration in both males and females resulted in significant decreases in the plasma concentration of each of the glucocorticoid groups both before and during the first week of the breeding season (June and early July), however during the last week of breeding (late July) dexamethasone decreased the plasma glucocorticoid concentration of females but not of males. Administration of ACTH caused a significant elevation in the plasma cortisol concentration in all groups. However, the magnitude of this response diminished with time in both sexes. Dexamethasone treatment resulted in a decrease in the plasma testosterone concentration in males before and early in the breeding season however toward the end of breeding this effect was abolished. It is apparent that towards the end of the breeding season and during the last week of life of the males, glucocorticoid feedback control of ACTH is almost abolished. These changes, which occur only in the males late in the breeding season and near the time of their disappearance from the population, are consistent with a condition known as end organ resistance to steroid hormones.

Adrenocorticotropic Hormone↗
PubMed2004

The influence of photoperiod on the reproductive activity of female Honey possums, Tarsipes rostratus (Marsupialia: Tarsipedidae): assessed by faecal progestagens and oestradiol-17beta.

Six female Honey possums were kept on a 15L:9D light regime to simulate a long daylength over summer. After seven weeks, three females (Group 2) were changed to a shorter daylength of 10L:14D, while the other three females (Group 1) were maintained on the long daylength. Faecal oestradiol-17beta and progestagen levels were measured during the experiment to detect any changes in reproductive rhythm, such as resumption of blastocyst development. Group 2 females were found to have very large and greatly expanded blastocysts with significantly higher levels of progestagens after the change to short photoperiod (p<0.05). In contrast, the Group 1 females had very small diapausing blastocysts and progestagen levels did not change throughout the study. Overall oestradiol levels also increased significantly in Group 2 females (p<0.05) but not in Group 1 females. These results demonstrate that a change from long to short days stimulates increased progestagen output (and oestradiol-17beta to a lesser extent) that supports the growth and expansion of the blastocysts. Photoperiod, in particular its change to a shortening daylength, appears to be a stimulus for terminating diapause in the Honey possum during its first reproduction of the year. However, as subsequent breeding later in the year occurs when daylength is increasing, a similar role for photoperiod cannot be attributed and females may be entrained to other factors such as food resources.

Animals↗
PubMed2004

Molecular phylogenetic relationships of two extinct potoroid marsupials, Potorous platyops and Caloprymnus campestris (Potoroinae: Marsupialia).

Complete 12S rRNA and partial cytochrome b (cytb) gene sequences have been obtained from museum samples of two recently extinct potoroids-Potorous platyops and Caloprymnus campestris. Phylogenetic analyses based on these mitochondrial DNA sequences suggest that the broad-faced potoroo (P. platyops) was a close relative of the recently discovered Potorous longipes and the recently re-discovered Potorous gilberti. Although the extinct desert rat-kangaroo (C. campestris) was clearly resolved as a member of the subfamily Potoroinae, its precise relationships vis a vis other living potoroines are unclear. We confirmed that the rufous rat-kangaroo (Aepyprymnus rufescens) is sister to all living Bettongia species, but the molecular data provide no support for a sister relationship between A. rufescens and C. campestris as suggested by on the basis of four shared morphological characters. Molecular dating analyses suggest that the initial radiation of potoroinae seems to have occurred soon after its origin in the early Miocene. Within Potoroinae, C. campestris diverged from other taxa approximately 16 million years ago. P. platyops diverged from P. longipes+P. gilberti approximately 14-15 million years ago.

Animals↗
PubMed1997

Extreme bilateral molar rotation in Monodelphis domestica (Marsupialia: Didelphidae).

Rotation of a tooth around an axis perpendicular to the occlusal plane through angles approaching 180 degrees is a rare anomaly found in the mammalian dentition. A specimen of Monodelphis domestica was found to show such extreme rotation of both lower last molars, with consequent disruption of normal occlusion and wear. A review of the literature discovered 41 other reported cases of extreme rotation, from four different orders of mammals. The distribution of extreme rotation within the dentition can be summarized as follows. It is found only in isolated teeth or in contralateral pairs of teeth. Bilateral rotation is far more common than would be expected based on the chance of the independent occurrence of two rotations. Extreme rotation has a significantly higher frequency in upper rather than lower teeth, in premolars rather than other teeth, and on the left- rather than the right--hand side. The incidence of extreme rotation across mammals was estimated to be approx. 1 in 5850.

Animal Diseases↗