PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “MARSUPIALIA”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1992

Specific chromosomal defects associated with ultraviolet radiation-induced cutaneous tumors in Monodelphis domestica (Marsupialia, mammalia).

Cytogenetic analysis of eight ultraviolet radiation (UVR)-induced cutaneous tumors and one spontaneously transformed fibroblast cell line of Monodelphis domestica showed that two of the tumor cell lines were of murine origin and that the remaining six marsupial tumor cell lines had hyperdiploid stemline numbers ranging from 21 to 31. Each tumor cell line showed structural and numerical abnormalities. The single transformed fibroblast cell line also showed a hyperdiploid chromosome number with structural and numerical defects. All M. domestica tumor cell lines and the fibroblast line showed a common structural abnormality: deletion of the short arm (p) of a chromosome 1. In some cell lines, the short arm of chromosome 1 was replaced by a translocation with the X chromosome. We suggest, based on the Giemsa-banding homology of chromosome 1p in M. domestica and human chromosome 6q involved in melanomas, that marsupial chromosome 1p may harbor tumor suppressor gene(s) that are associated with UVR-induced cutaneous tumors.

Animals↗
PubMed1985

Hibernation in pygmy possums (Marsupialia: Burramyidae).

The minimum body temperatures and the longest torpor bouts recorded for pygmy possums (family Burramyidae) are compared with hibernating representatives from the insectivores, rodents and Australian bats. The lowest body temperatures of pygmy possums are around 6 degrees C which is within the range of the other mammalian groups. The torpor bouts of the pygmy possums last up to two weeks and the durations are similar to those of eutherian hibernators.

Animals↗
PubMed1996

Quantitative urinary excretion of unmetabolised N tau-[Me-14C] methylhistidine by the common ringtail possum (Pseudocheirus peregrinus) marsupialia.

Six common ringtail possums (Pseudocheirus peregrinus) were intravenously injected with a standard dose of radioactive 3-Methylhistidine (N tau-[Me-14C]MeH). The dose was rapidly and quantitatively excreted by the possums. More than 90% of radioactivity was recovered within 3 days. Thin layer chromatography and mass spectroscopy showed that 97% of recovered radioactivity was associated with unmetabolised N tau-[Me-14C]MeH. These data satisfy two key requirements for the validity of urinary 3-Methylhistidine (N tau-3MeH) excretion as an index of muscle protein catabolism, in P. peregrinus.

Animals↗
PubMed1995

Neuron-specific enolase as a marker of hypothalamo-neurohypophyseal development in postnatal Monodelphis domestica (Marsupialia).

In the newborn Monodelphis domestica, pituitary and brain are far from their definite shape and structural organization. The presumptive neurohypophysis appears as a mass of proliferating cell immunonegative for neuron-specific enolase (NSE) in the newborn, while perikarya positive for NSE are present in the rostroventral area of the hypothalamus. At the same time, the periventricular areas of the brain, consisting of proliferating cells, are non-reactive for NSE. In the 2.5-day-old specimens of this study, the neurohypophysis displays anti-NSE reactions in the peripheral regions. In animals 8-10 days of age, the amount of reaction product in the neurohypophysis has reached highest levels. This dramatic increase parallels the increase of NSE expression in perikarya of the rostroventral and caudoventral hypothalamus as well as the formation of a band-like reaction zone between the respective hypothalamic areas and the neurohypophysis.

Animals↗
PubMed2005

New DNA data from a transthyretin nuclear intron suggest an Oligocene to Miocene diversification of living South America opossums (Marsupialia: Didelphidae).

Phylogenetic relationships of 19 species of didelphid marsupials were studied using two nuclear markers, the non-coding transthyretin intron 1 (TTR) and the coding interphotoreceptor retinoid binding protein exon 1 (IRBP), and two mitochondrial genes, the protein-coding cytochrome b (cyt-b) and the structural 12S ribosomal DNA (12S rDNA). Evolutionary dynamics of these four markers were compared to each other, revealing the appropriate properties presented by TTR intron 1 together with its well supported and resolved phylogenetic signal. Nuclear markers supported the monophyly of medium and large-sized opossums Metachirus+(Chironectes, Lutreolina, Didelphis, Philander), and the paraphyly of mouse-sized opossums, with the genera Gracilinanus, Thylamys, and Marmosops as a sister group to medium and large-sized didelphids. Conflicting branching patterns between mitochondrial and nuclear data involved the phylogenetic position of Marmosa-Micoureus-Monodelphis relative to other mouse-sized opossums. Nuclear phylogenetic inferences among genera were confirmed by the presence of synapomorphic indels observed in TTR intron 1. A Bayesian relaxed molecular clock dating of didelphid evolution using nuclear markers estimated their origin in the Middle Eocene (39.8 million years ago), with subsequent diversification during the Oligocene (Deseadan) and Miocene.

Animals↗
PubMed1998

Ultrastructural pattern of glucagon producing-cells in the gastric mucosa of the developing opossum Didelphis albiventris (Marsupialia).

Gastric glucagon-producing cells of the pouch young, weaned and adult opossum Didelphis albiventris were investigated by immunocytochemical and ultrastructural methods. In sections of the oxyntic mucosa stained by immunoperoxidase it was observed that glucagon-immunoreactive cells increased in number during pouch development (from 7.9 +/- 4.7 to 35.4 +/- 5.9 cells/mm2), decreasing progressively to weaned (14.2 +/- 4.8 cells/mm2) and adult animals (10.4 +/- 3.0 cells/mm2). The glucagon-immunoreactive cells presented numerous electrondense, round cytoplasmic granules surrounded by a membrane. Frequently, the dense core of the granules was separated from the enveloping membrane by a delicate electronlucent halo or by a less electrondense peripheral halo. This pattern of the granular component was similar to the ultrastructural morphology observed in pancreatic islet glucagon-producing cells and A-like cells of the gastric mucosa of those eutherian mammals studied so far.

Animals↗
PubMed1998

Mapping the distribution of the telomeric sequence (T2AG3)n in the Macropodoidea (Marsupialia), by fluorescence in situ hybridization. I. The swamp wallaby, Wallabia bicolor.

Thylogale spp. (pademelons) retain the plesiomorphic (ancestral) 2n = 22 karyotype for the marsupial family Macropodidae (kangaroos and wallabies). The swamp wallaby, Wallabia bicolor, has the most derived macropodid karyotype with the lowest chromosome number (2n = 10 female, 11 male), and a multiple sex chromosome system (XX female, XY1Y2 male). All but one of the W. bicolor chromosomes are fusion chromosomes. Two of these chromosomes, the X chromosome and chromosome 1, are composed of three plesiomorphic Thylogale-like chromosomes. The distribution of the vertebrate telomeric sequence (T2AG3)n was examined by fluorescence in situ hybridization (FISH) in both species and a 'map' of non-telomeric (T2AG3)n sites on W. bicolor chromosomes relative to Thylogale chromosomes was constructed. (T2AG3)n signals were observed at six fusion sites in the four fusions chromosomes examined, indicating that the (T2AG3)n sequence is consistently retained during fusions. The distribution of the interstitial signals on the long arm of chromosome 1 of W. bicolor and the X chromosome suggests how a combination of inversions, fusions and centromeric transpositions have resulted in interstitial telomeric sequence.

Animals↗
PubMed2002

Redescription of Zoniolaimus mawsonae Beveridge, 1983 (Nematoda: Strongyloidea) and the description of Z. latebrosus n. sp. from the red kangaroo Macropus rufus (Marsupialia: Macropodidae) based on morphological and molecular data.

This study shows that the description of Z. mawsonae given by Beveridge (1983) represented a composite of two species. Hence, Z. mawsonae Beveridge, 1983 is re-described and a new species, Z. latebrosus, is described. Males of the two species differ in the lengths of their spicules (0.94-1.23 mm in Z. mawsonae compared with 1.53-1.95 mm in Z. latebrosus) and in several characteristics of the bursa and genital cone. Females of the two species can be identified based on the shape of the posterior end of the body, that of Z. mawsonae being markedly swollen. Molecular data, obtained from single strand conformation polymorphism (SSCP) analysis and DNA sequencing of the second internal transcribed spacer of ribosomal DNA, provided additional support for the separation of the two species.

Animals↗
PubMed2002

Review of Papillostrongylus Johnston & Mawson, 1939 (Nematoda: Strongyloidea) from wallabies and kangaroos (Marsupialia: Macropodidae) using morphological and molecular techniques, with the description of P. barbatus n. sp.

The strongyloid nematode genus Papillostrongylus Johnston & Mawson, 1939, from kangaroos and wallabies, is reviewed using morphological and molecular methods. P. labiatus Johnston & Mawson, 1939 is re-described from material from the type-host, the black-striped wallaby Macropus dorsalis, from eastern Queensland, Australia, in which it is a relatively common parasite. Additional records from M. parryi and Thylogale thetis are confirmed and considered to represent examples of host-switching. A geographically disjunct population of the nematode species occurs in M. bernardus and Petrogale brachyotis in Arnhem Land, Northern Territory, but assessment of its status requires additional material. Nematodes from M. rufus, M. giganteus, M. fuliginosus and M. robustus from inland regions of Australia, formerly attributed to P. labiatus, are here assigned to a new species, P. barbatus, distinguished by the presence of an external leaf-crown, larger size, by greater spicule length in the male and by a sinuous vagina in the female. Additional hosts of P. barbatus n. sp. are Petrogale assimilis and Pet. lateralis purpureicollis. Sequence analyses of the second internal transcribed spacer of ribosomal DNA (ITS-2) also showed that P. barbatus n. sp. differed at 40 (16.7%) of the 240 alignment positions when compared with P. labiatus. Most of these interspecific sequence differences occurred in loops or bulges of the predicted precursor rRNA secondary structure, or represented partial or total compenstory base pair changes in stems.

Animals↗
PubMed2004

Mapping the distribution of the telomeric sequence (T2AG3)n in the 2n = 14 ancestral marsupial complement and in the macropodines (Marsupialia: Macropodidae) by fluorescence in situ hybridization.

In this study we test the theory that the presence of the conserved vertebrate telomeric sequence (T(2)AG(3))(n) at the centromeres of Australian marsupial 2n = 14 complements is evidence that these karyotypes are recently derived, which is contrary to the generally held view that the 2n = 14 karyotype is ancestral for Australasian and American marsupials. Here we compare the distribution of the (T(2)AG(3))( n ) sequence and constitutive heterochromatin in the presumed ancestral 2n = 14 complement and in complements with known rearrangements. We found that where there were moderate to large amounts of constitutive heterochromatin, the distribution of the (T(2)AG(3))(n) sequence reflected its presence as a native component of satellite DNA rather than its involvement in past rearrangements. The presence of centromeric heterochromatin in all Australian 2n = 14 complements therefore suggests that centromeric sites of the (T(2)AG(3))(n) sequence do not represent evidence for recent rearrangements.

Animals↗
PubMed2003

Progamotaenia capricorniensis sp. nov. (Cestoda: Anoplocephalidae) from wallabies (Marsupialia: Macropodidae) from Queensland, Australia.

Progamotaenia capricorniensis sp. nov. (Cestoda: Anoplocephalidae) is described from the wallabies Macropus dorsalis (Gray, 1837) and Petrogale assimilis Ramsay, 1877 from Queensland, Australia. The new species is characterised by a fimbriated velum composed of 26-32 digitiform to triangular projections on each side of the proglottis, paired uteri and 140-190 testes distributed in a single band across the medulla. Minor variation occurs in the distribution of the testes. The above characters distinguish the new species from its most closely related congeners P. lagorchestis (Lewis, 1914), P. proterogyna (Fuhrmann, 1932), P. spearei Beveridge, 1980 and P. villosa (Lewis, 1914). P. capricorniensis appears to exhibit a highly disjunct distribution within its usual host, M. dorsalis.

Animals↗
PubMed1989

Changes in milk carbohydrates during lactation in the common brushtail possum, Trichosurus vulpecula (Marsupialia:Phalangeridae).

Milk samples (186) were obtained at various stages of lactation from 27 common brushtail possums (Trichosurus vulpecula). Qualitative and quantitative changes in the milk carbohydrates during early and mid-lactation were similar to those previously seen in other marsupials; the principal carbohydrate was lactose early in lactation and higher oligosaccharides in mid-lactation, and the hexose concentration reached a peak during mid-lactation. However, the late-lactation milk was unusual in that the carbohydrate was mainly lactose and its concentration remained relatively high (3.5 to 5.5%). In contrast to earlier findings on the milk of the tammar wallaby (Macropus eugenii), little or no nucleotide pyrophosphatase, beta-galactosidase and alkaline phosphatase activities were detected late in lactation.

Alkaline Phosphatase↗
PubMed1989

Intestinal lactase (beta-galactosidase) and other disaccharidase activities of suckling and adult common brushtail possums, Trichosurus vulpecula (Marsupialia:Phalangeridae).

Small-intestinal disaccharidase activities of eight suckling T. vulpecula, aged from 34 to 150 days, and of two adult animals were investigated. Intestinal maltase, isomaltase and sucrase activities increased with age, whereas lactase activities decreased. Trehalase activities were relatively high in all animals and showed no obvious age-related changes. Three separate beta-galactosidase activities, one neutral and two acid, acted on lactose. The neutral beta-galactosidase activity appeared to be due to a brush border enzyme similar to that of eutherian mammals, whereas the acid beta-galactosidases were soluble and probably of lysosomal origin. One of these, acid beta-galactosidase-1, had similar properties to the sole intestinal beta-galactosidase of macropodid marsupials, whereas the other, acid beta-galactosidase-2, has not previously been described. Galactosyl oligosaccharides isolated from macropodid milk were readily hydrolysed by both acid beta-galactosidases but not by the neutral beta-galactosidase. The total intestinal lactase activity in animals aged up to 125 days was due mainly to acid beta-galactosidase-1, whereas in older animals it was due mostly to the neutral beta-galactosidase; this suggests that late in lactation the young T. vulpecula change from a macropodid mode of digestion of galactosyl oligosaccharides to a eutherian mechanism for the digestion of lactose. These findings may have implications for the hand-rearing of orphaned T. vulpecula.

Animals↗
PubMed1992

Maternal recognition of pregnancy in the Tasmanian bettong, Bettongia gaimardi (Marsupialia: Macropodoidea).

The fetus of the marsupial Bettongia gaimardi, the Tasmanian bettong, has both morphological and cytological effects upon the gravid uterus. Development of diapausing embryos or the initiation of oestrous cycles was achieved by removal of the pouch young (RPY). Increases in the diameter of the uterine basal endometrial glands were noted 3 and 4 days later. An animal at Day 5 after RPY had glands in the gravid uterus that were significantly larger than those in the non-gravid uterus (P less than 0.01). This difference was also found in non-pregnant animals before Day 11 and was believed to be due to the local presence of the corpus luteum. Thereafter, significant differences were only found in pregnant animals until parturition at Day 17 or 18 after RPY. These differences were attributed to the local effect of the fetus and reflect a 'maternal recognition of pregnancy', as found in other macropodoid species.

Animals↗
PubMed1992

Duration of the cycle of the seminiferous epithelium and quantitative histology of the testis of the South American white-belly opossum (Didelphis albiventris), Marsupialia.

The duration of the cycle of the seminiferous epithelium of the South American white-belly opossum, as obtained by autoradiography after intratesticular injection of tritiated thymidine, was estimated to be 17.3 +/- 0.1 days (mean +/- s.d.). Quantitative histological analysis was performed on testes from animals caught both in mating and non-mating periods of the annual reproductive cycle. Significant differences were found in the volumetric proportion of Leydig cells, but the spermatogenic yield remained constant throughout the year. The numerical ratio between type A spermatogonia and zygotene primary spermatocytes (1:12.0), as well as daily sperm production (4.8 x 10(6) sperm cells per g of testis parenchyma per day), were found to be lower than those reported in most eutherian mammals.

Animals↗
PubMed1992

Protein synthesis and secretion by the epididymis of the tammar wallaby, Macropus eugenii (Macropodidae: Marsupialia).

The objectives were to assess the following in a marsupial: which proteins are synthesized by the different regions of the epididymis and secreted into the lumen of the ductus; the effect of the experimental method on the detection of protein secretion; the role of the testis in regulating the protein synthesis and secretion; and whether any of the secreted proteins may associate with spermatozoa. Samples from untreated animals were collected for examination by perfusing Krebs-bicarbonate through the ductus epididymidis in vivo (microperfusion), and after incorporation of [35S]methionine during incubation of minced duct in vitro. Electrophoresis of the samples showed that the caput and corpus epididymidis (initial segments) secreted most of the proteins that were synthesized and secreted by the epididymal mucosa, and that the cauda epididymidis secreted mainly blood proteins. Also, many more proteins were secreted in vitro than into the microperfusates in vivo, or were found by Jones (1987) in micropuncture samples of epididymal plasma. The synthesis and secretion of five proteins was androgen dependent (M(r) 75,700, 30,000, 18,700, 17,400 and 12,800). Also, the luminal fluids from the testis stimulated the secretion of two proteins (M(r) 46,300 and 36,100) and inhibited the secretion of three proteins (M(r) 43,000, 32,300 and 21,400). Examination of detergent extracts of spermatozoa indicated that they lose three proteins (M(r) 28,000, 30,000 and 47,000) and gain one (M(r) 30,400) during passage through the epididymis. The method of determining protein secretion affected the findings. Protein secretion, its control and its association with spermatozoa are broadly similar in the tammar wallaby to the processes described in eutherian mammals.

Analysis of Variance↗
PubMed1994

Interactions of sperm and the reproductive ducts of the male tammar wallaby, Macropus eugenii (Macropodidae: Marsupialia).

This review compares sperm production in the tammar wallaby and eutherian mammals, particularly the rat. The capacity of sperm to fertilize an ovum when they leave the testis and the changes they undergo in the epididymidis are considered. The structural differentiation and regulation of the extratesticular duct system is assessed and related to the reabsorption and secretion of water, inorganic ions and proteins, and the interaction of sperm and proteins synthesized and secreted by the epididymidis. Adaptations of the cauda epididymidis for storing spermatozoa are also considered. It is suggested that the tammar may be a good animal model to study the suppression of sperm motility and metabolism in the cauda epididymidis as it is possible to collect from them luminal samples of sperm which are initially immotile and then spontaneously activate during incubation in vitro.

Animals↗