Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “marsupial”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 19 recordsLinked to original sources
PubMed1979

Marsupial--mouse cell hybrids containing fragments of the marsupial X chromosome.

Hybrids were obtained from fusions of HPRT-deficient mouse fibroblasts and marsupial lymphocytes. These hybrids retained no identifiable marsupial chromosomes, but all expressed the marsupial form of HPRT. Half the clones also expressed marsupial PGK-A, and half of these also marsupial G6PD; no other marsupial allozyme markers were detected. Since G6PD is known to be sex linked in these species, we conclude that Hpt and Pgk-A are also located on the X chromosome and the markers lie in the order Hpt-Pgk-A-Gpd.

Animals↗
PubMed1978

The use of marsupial x eutherian somatic cell hybrids to study marsupial cell surface antigens.

Buck and Bodmer (1976) have developed a technique for identifying an antigen on the surface of human x mouse somatic cell hybrids, specified by a gene on a particular human chromosome. We have successfully adapted this technique to a study of marsupial cell surface antigens. Somatic cell hybrids between Macropus rufus (Marsupialia) lymphocytes and the mouse cell lines PG19 and 1R were injected intraperitoneally into mice of the same inbred strain from which the above cell lines were derived (C57B16J and C3H, respectively). The only identified M. rufus chromosome present in the hybrid cells was the X chromosome. The antisera, after adsorption with PG19 or 1R, were tested using indirect immunofluorescence, against the hybrid cells, and also against sub-clones (derived from hybrids) which had apparently lost the M. rufus X chromosome, or at least its long arm. The results of these tests showed that the absorbed antisera contained reactivity against an M. rufus cell surface antigen (or antigens). The reactions of one of the antisera were most simply interpreted by supposing that it was detecting an M. rufus X-lined antigen(s).

Animals↗
PubMed1978

Fusion and hybridization of marsupial and eutherian cells. V. Development of selective systems.

The availability of systems which permit the selective elimination of marsupial cells from fused cultures is an essential requirement for the production of marsupial X eutherian somatic cell hybrids. Such hybrids have particular advantages for genetic studies of mammalian cells. We describe the isolation and characterization of several drug-resistant marsupial cell strains. We have selected strains resistant to concentrations of 10 micrograms/ml of the purine analogues 8-azaguanine and 6-thioguanine. Several of these strains were found to be deficient in the enzyme hypoxanthine phosphoribosyltransferase and consequently sensitive to hypoxanthine-aminopterin-thymidine (HAT) selective medium. We have also isolated marsupial cell strains resistant to concentrations of 22 micrograms/ml of the thymidine analogue 5-bromodeoxyuridine. These strains were thymidine kinase deficient and HAT sensitive. Drug resistance was a stable characteristic maintained for many generations in the absence of the drug. However, inhibition of growth of these drug-resistant strains was strongly density dependent, a factor that caused difficulties in the selection of hybrids. We have also developed selective systems which exploit differences between marsupial and eutherian cells in sensitivity to growth in ouabain, and in adhesiveness and other growth properties. Marsupial cells were found to be naturally much more sensitive to ouabain than rodent cells, a phenomenon that should be useful in the selection of marsupial X rodent cellular hybrids. We discuss a number of difficulties associated with the derivation and use of variant marsupial cell strains.

Animals↗
PubMed1977

Oxygen affinity and 2,3-diphosphoglycerate in blood of Australian marsupials of differing body size.

Oxygen carriage and 2,3-diphosphoglycerate (2,3-DPG) levels have been measured in the blood of seven species of Australian marsupials ranging in size from 35 to 0.03 kg. They were Red and Grey Kangaroos, Wallaroo, Tammar Wallaby, Brush-tailed possum, Potoroo, and Brown Marsupial Mouse. Oxygen affinity decreased with decrease in adult body size, standard P50 (at 36 C) varying from 24.6 torr in the largest (Red Kangaroo) to 41.9 torr in the smallest (Brown Marsupial Mouse). The relationship between P50 and body size is similar to the relationship which has been described previously for eutherian mammals. The Bohr factor (--deltalog P50/deltapH) and value for Hill n were generally in the range found for other land-dwelling mammals. All species had 2,3-DPG in their erythrocytes acting as a regulator of oxygen affinity. The polymorphism at position beta 2 in hemoglobin of the Grey Kangaroo was shown to affect the respiratory properties of the molecule. When beta 2 = histidine, which has a positively charged side chain, erythrocyte 2,3-DPG was higher, and P50 was higher, than when beta 2 = glutamine which has a neutral side chain.

Animals↗
PubMed1977

Fusion and hybridization of marsupial and eutherian cells. Heterokaryon formation.

Marsupial x eutherian cell hybrids would be very useful for studies of mammalian genetics and cell biology. A critical step in the formation of such hybrids is the fusion of cells to form heterokaryons. We have examined many different combinations of marsupial and eutherian cells for their ability to fuse, and we have found that all combinations yielded heterokaryons, but with different frequencies, depending on the cell types used. Ranked in order of decreasing ability to fuse with eutherian cells, the marsupial cell types were; established lines, primary diploid fibroblasts and lymphocytes. In all fusion experiments there was a marked preference for the formation of homokaryons compared with heterokaryons. It was possible to control the numbers and types of heterokaryons formed by varying the input ratio of parental cells.

Animals↗
PubMed1975

Histamine in the tissues of the marsupial Setonix brachyurus (the quokka).

Passive cutaneous anaphylactic (PCA) reactions in the marsupial Setonix brachyurus (the quokka) were completely inhibited by the histamine antagonist mepyramine maleate, but were unaffected by disodium cromoglycate or the serotonin antagonist, methysergide. Histological examination of quokka skin indicated that mast cell degranulation occurred during the PCA reaction in this marsupial and animals whose skin was relatively deficient in mast cells were poor PCA recipients. In contrast to many eutherian (placental) species, this marsupial was found to lack histamine in blood leukocytes and platelets. Also, while the peritoneal mast cells of rats and mice contain large quantities of histamine, this amine was not detected to quokka peritoneal washings, even after the induction of a peritoneal exudate or the regular intraperitoneal injection of antigen. Immunologic challenge of quokka blood or peritoneal cells did not induce the synthesis of histamine, but histamine release was elicited from sensitized quokka lung by antigenic challenge.

Animals↗
PubMed1977

Marsupial immunoglobulins: the distribution and evolution of macropod IgG2, IgG1, IgM and light chain antigenic markers within the sub-class Metatheria.

The distribution within Australian and American marsupials of the heavy and light chain antigenic markers identified by antisera to purified quokka (Setonix brachyurus) immunoglobulins is described. Markers for IgM and IgG2 constant region determinants as well as for light chains were widely distributed in Australian species and were also detected in Didelphis, the American opossum, thus indicating a long-term structural conservatism of some immunoglobulins within the marsupials. More detailed analysis of the distribution of quokka IgG2 determinants by quantitative precipitation and sequential absorption procedures suggested that there had been a gradual and cumulative acquisition of these markers with time. The presence of IgG2 markers in species separated for 130 million years (quokka and opossum) suggested that IgG2 was the ancestral IgG present before the divergence of these separate lines. The origin of IgG1 remains obscure as it appears to be limited to a small group of closely related diprotodont marsupials suggesting a recent origin.

Animals↗
PubMed1979

A histochemical study of denervated marsupial hemidiaphragm.

The marsupial (quokka) hemidiaphragm showed postdenervation hypertrophy and subsequent atrophy. The type II muscle fibres hypertrophied up to 20 days postoperation and then regressed. However, the type I fibres hypertrophied throughout the experimental period (100 days) studied. Unlike denervated eutherian hemidiaphragm, fibre-splitting was absent in the denervated marsupial muscle. An enhancement of the ATPase reaction in the denervated type I fibres may be due to dedifferentiation. Presumably innervation exerts a 'negative control' and prevents increase of type I fibre size in the normal hemidiaphragm.

Adenosine Triphosphatases↗
PubMed1975

Galactose metabolism in relation to cataract formation in marsupials.

Erythrocytic galactokinase and/or galactose-1-phosphate uridyl transferase activity were low in many species of marsupials. However, cataract formation was observed only in pouch-young members of these species when reared on cow's milk. The galactose tolerance of young kangaroos was found to be greatly impaired, but improved rapidly and markedly at the stage of which the definitive structure of the ruminant type of stomach as in adults is formed. The combination of high absorption of galactose and low levels of galactokinase and/or transferase thus appears to determine the predisposition of pouch-young marsupials to galactose cataractogenesis.

Adult↗
PubMed1978

Widespread occurrence in Australian marsupials of neutralizing antibodies to a herpesvirus from a parma wallaby.

Serum neutralizing antibodies to a parma wallaby herpesvirus (PWHV) have been detected in a wide range of marsupials from different locations across Australia, including several islands. A study of 242 animals (mostly macropods) sampled in the wild showed that 23% had antibodies; a significantly higher frequency (41%) of 116 animals in captivity had antibodies, which were generally at higher levels than those of animals in the wild. Antibodies to PWHV were also detected among parma wallabies from a colony on Kawau Island, New Zealand. The highest antibody levels were found in a group of captive tammar wallabies during recurrent outbreaks of clinical infection. It is suggested that PWHV has evolved along with a marsupial host, and that the high antibody levels among captive animals reflects ease of virus transmission due to crowding, or to conditions of stress leading to expression of latent virus.

Animals↗
PubMed1977

Marsupial cells in long-term culture.

Cell lines have been developed from several species of Australian marsupials and studied during long-term growth. Cell lines developed from macropodid skin or heart tissues all had reproducible finite life-spans. However, cell lines developed from dasyurids showed bariable behavior in culture: lines developed from Antechinus stuartii and Dasyurus viverrinus had finite life-spans, while lines developed from Sminthopsis crassicaudata had indefinite life-spans. S. crassicaudata lines usually became heteroplloid, but one was still diploid after 150 population doublings, while another contained a proportion (10%) of haploid cells. Other lines were developed from the peramelid, Perameles nasuta, and the phanlngerid, Trichosurus vulpecula.

Animals↗
PubMed1978

The auditory midbrain of a marsupial: the brush-tailed possum (Trichosurus vulpecula).

A microelectrode survey was made of the midbrain auditory nuclei of the brushtailed possum (Trichosurus vulpecula), a common Australian marsupial. Information was sought on the tuning characteristics of individual neurones, tonotopic organization and mechanisms of sound localization. It was felt that such information would be of use in future studies of the development and evolution of mammalian hearing. Twelve possums were anaesthetized with ketamine and chloralose-urethane, and recordings were made of extracellular unit discharges in the inferior colliculus during monaural and binaural tonal stimulation. The inferior colliculus of the possum consists of a central nucleus - a darkly stained, densely packed group of cells - flanked laterally by an external nucleus with a lower density of paler cells. Tonotopic organization was demonstrated by discretelytuned elements in the central nucleus, but was not observed in the external nucleus. In the latter region broad and irregular tuning was commonly seen. Most units in both divisions were influenced by binaural stimuli, with patterns of binaural interaction similar to those observed in the cat inferior colliculus. Cells influenced by changes in the interaural time and intensity difference were commonly observed, but only a subclass of these were suited in sensitivity for sound localization. In general, the midbrain auditory system of the possum was similar in unit discharge characteristics and organization to those of the eutherian mammals commonly studied.

Acoustic Stimulation↗
PubMed1979

A marsupial oncovirus?

A virus-like particle was observed in two continuous cell lines derived from the marsupial Sminthopsis crassicaudata (Fat-tailed Dunnart). The development of the particle was similar to the development of D-type oncoviruses. Initially, a crescentof nucleoid material was observed near the nucleus in the region of the Golgi apparatus. This crescent developed into a doughnut-shaped-A-type particle which migrated through the cytoplasm towards the cell membrane where it budded either into a smooth membrane cytoplasmic vacuole or from the cell membrane. Only enveloped A-type particles were observed; no mature B-type, C-type or D-type particles were detected.

Animals↗
PubMed1979

Ratio of inferior olivary cells to Purkinje cells in a marsupial (Trichosurus vulpecula).

An indirect estimate of the extent of branching of the olivary axons in the cerebellum in a marsupial (Trichosurus vulpecula) was carried out. The cells in the inferior olivary nuclear complex (IOC) of both sides were estimated (mean = 57,200), as were the cerebellar Purkinje cells (mean = 881,300). Assuming that all climbing fibers arise from IOC cells and that each Purkinje cell receives a climbing fiber input, each IOC cell sends climbing fiber terminals to 15 Purkinje cells.

Animals↗
PubMed1976

Blood corticosteroids in Australian marsupial and placental mammals and one monotreme.

Peripheral blood corticosteroid levels were determined in nine species of Australian marsupial (Eastern grey kangaroo, black-tailed, Bennett's and pademelon wallabies, quokka, wombat, koala and Western native and tiger cats), one species of monotreme (echidna) and one placental Australian mammal (dingo). Animals were obtained or bled with minimal disturbance and came from areas considered to have adequate sodium content of the vegetation. Aldosterone, corticosterone, cortisol, 11-deoxycorticosterone and 11-deoxycortisol were measured and levels found to be similar to five introduced eutherian species (sheep, cow, dog, fox and man) with the exception of the koala and the wombat. Cortisol was the predominant corticosteroid, except in the koala, which produced corticosterone in relatively the greatest quantity, and the wombat which produced more 11-deoxycortisol. Steroid levels were generally low in the wombat. ACTH administered to the koala changed its pattern of corticosteroid secretion from predominantly corticosterone to cortisol. In the dingo, administration of ACTH caused rises in corticosteroid levels similar to those seen in most other eutherian mammals.

Adrenal Cortex Hormones↗
PubMed1978

Plasma testosterone profiles in male macropodid marsupials.

Serial blood samples were collected over a 3.5-8 h period from ten adult male macropodid marsupials belonging to five different species to study the pattern of testosterone secretion. The concentration of testosterone in the plasma ranged from 0.5 to 9.5 ng/ml, and in each animal the levels declined progressively during the study; this effect was attributed to the stress effects of handling. Injection of 5 microgram synthetic luteinizing hormone releasing hormone induced a rapid and substantial increase in the level of testosterone.

Animals↗