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At least 667 records · Page 37Linked to original sources
PubMed1992

Warm-up rates during arousal from torpor in heterothermic mammals: physiological correlates and a comparison with heterothermic insects.

This study examines the relationship between warm-up rate, body mass, metabolic rate, thermal conductance and normothermic body temperature in heterothermic mammals during arousal from torpor. Predictions based on the assumption that the energetic cost of arousal has been minimised are tested using data for 35 species. The observation that across-species warm-up rate correlates negatively with body mass is confirmed using a comparative technique which removes confounding effects due to the non-independence of species data due to shared common ancestry. Mean warm-up rate during arousal correlates negatively with basal metabolic rate and positively with the temperature difference through which the animal warms, having controlled for other factors. These results suggest that selection has operated to minimise the overall energetic cost of warm-up. In contrast, peak warm-up rate during arousal correlates positively with peak metabolic rate during arousal, and negatively with thermal conductance, when body mass has been taken into account. These results suggest that peak warm-up rate is more sensitive to the fundamental processes of heat generation and loss. Although heterothermic marsupials have lower normothermic body temperatures and basal metabolic rates, marsupials and heterothermic eutherian mammals do not differ systematically in warm-up rate. Pre-flight warm-up rates in one group of endothermic insects, the bees, are significantly higher than predictions based on rates of arousal of a mammal of the same body mass.

Animals↗
PubMed1992

Evidence for the coexistence of serotonin and calcitonin gene-related peptide at the subcellular level in neuroepithelial bodies in the lung of a marsupial, Isoodon macrourus.

The coexistence of serotonin and calcitonin gene-related peptide (CGRP) in neuroepithelial bodies of the bandicoot, Isoodon macrourus, has been examined using immunocytochemistry at the light- and electron-microscope levels. The avidin-biotin technique of antigen localisation was used initially to identify serotonin-like and CGRP-like immunoreactivity (-LI). Serotonin-LI and CGRP-LI were found in neuroepithelial cells in the lungs of 30-day-old bandicoots. CGRP-LI could also be demonstrated in nerve fibres associated with some neuroepithelial bodies. The protein A-gold technique of antigen localisation was used to label neuroepithelial cells and nerve fibres at the subcellular level. Serotonin-LI and CGRP-LI were observed in the same dense-cored vesicles of most neuroepithelial cells; however, some neuroepithelial cells were shown to possess serotonin-LI without CGRP-LI. Nerve fibres immediately adjacent to neuroepithelial bodies exhibited mainly CGRP-LI. These results show that serotonin-LI and CGRP-LI are present in neuroepithelial cells of the bandicoot in the same secretory vesicles. This pattern of co-localisation may reflect co-ordinated or synergistic actions of these two neuroactive substances.

Animals↗
PubMed1975

Klossiella spp. in the kidneys of peramelid, petaurid, and macropodid marsupials.

Klossiella spp. were found in kidneys of individuals from six genera in two of the three superfamilies of Australian marsupials. Klossiella quimrensis sp.n. is described in the bandicoots, Isoodon obesulus and Perameles gunnii (Peramelidae). K. convolutor sp.n. is described in the ringtail possum Pseudocheirus peregrinus (Petauridae). Three macropodid genera were infected. K.serendipensis sp.n. is described in the swamp wallaby, Wallabia bicolor, and K. callitris sp.n. is described in the western grey kangaroo, Macropus fuliginosus. Multinucleate bodies considered to be schizonts of a Klossiella sp. were observed in the kidneys of the potoroo, Potorous apicalis. Gametocytes only of K. serendipensis were seen, while gametogony and sporogony of K. convolutor and K. callitris were observed.

Animals↗
PubMed1975

Pneumocystis carinii infections in zoo animals.

Pneumocystis carinii was found to be present in the lungs of twenty-three zoo animals in the Netherlands. The following species were represented: red kangaroo, common tree shrew, Senegal-Galago, Demidoff's-Galago, brown howler monkey, woolly monkey, long-haired spider monkey, white-eared marmoset, chimpanzee, three-toed sloth, palm squirrel, red panda, fennec fox, tree hyrax and large-toothed hyrax.

Animals↗
PubMed1993

Three-dimensional organization of the ribosomal genes and Ag-NOR proteins during interphase and mitosis in PtK1 cells studied by confocal microscopy.

The three-dimensional (3-D) organization of rDNA-containing chromatin and the set of protein markers of active ribosomal genes, the Ag-NOR proteins, were investigated by confocal laser scanning microscopy (CLSM). The rDNA genes of marsupial cells (PtK1) were mapped using biotinylated DNA probes for 45S rDNA sequences and the Ag-NOR protein distribution was revealed by specific Ag-NOR staining. We used PtK1 cells because each nucleolus possesses only one nucleolar organizer region (NOR). In metaphase chromosomes, nonisotopic in situ hybridization demonstrated the presence of rDNA in the secondary constriction of the X chromosomes with an axial distribution and also lateral expansions. 3-D reconstruction of the Ag-NOR protein signals revealed the presence of these proteins in the secondary constriction where they formed a crescent-shaped structure around the axial chromatin pedicule. The organization of the secondary constriction in PtK1 chromosomes is discussed. During interphase, nonisotopic in situ hybridization in intact cell monolayers and isolated nuclei showed the rDNA genes distributed as intense fluorescent spots linked by weak signals in the inner regions of the nucleoli. We conclude that the rDNA is not homogeneously distributed in the internal regions of the nucleoli. In the same nucleolar regions, the Ag-NOR proteins were revealed as granules linked by thin filaments. These images indicate similar 3-D distributions for rDNA probes and Ag-NOR proteins. The beaded organization of the transcriptional regions in the nucleoli is discussed.

Animals↗
PubMed1986

Development of visual projections in the marsupial, Setonix brachyurus.

Retinal projections to the primary visual centres were studied following injection of tritiated proline into one eye in the Marsupial, Setonix brachyurus between 10 and 100 days postnatal and in adults. Initially, projections from the two eyes overlapped extensively, particularly between 20 and 50 days. There was a gradual refinement thereafter, including a segregation of inputs from the two eyes within both the lateral geniculate nucleus (LGN) and superior colliculus (SC) by 70 days. Such refinement in visual centres is discussed in relation to the concurrent emergence of retinal ganglion cell density gradients, a decrease in ganglion cell numbers, cell death in the ganglion cell layer and loss of optic axonal profiles.

Aging↗
PubMed1995

Secretion of electrolytes, protein and urea by the mandibular gland of the common wombat (Vombatus ursinus).

Saliva was collected from the mandibular glands of anaesthetized common wombats (Vombatus ursinus) to ascertain maximal flow rates, salivary composition and possible adaptations, particularly PO4(3-) secretion, to assist digestion. After temporary catheterization of the main duct through its oral opening, salivary secretion was evoked at flow rates ranging from 0.02 +/- 0.002 (+/- SEM) ml.min-1 (0.7 +/- 0.07 microliter.min-1.kg body weight-1) to 0.4 +/- 0.05 ml.min-1 (14 +/- 1.9 microliters.min-1.kg body weight-1) by ipsilateral intracarotid infusion of acetylcholine. The [Na+] (15 +/- 5.1 to 58 +/- 8.6 mmol.l-1) and [HCO3-] (35 +/- 1.9 to 60 +/- 1.9 mmol.l-1) were positively correlated with salivary flow rate. The [K+] (58 +/- 5.2 to 30 +/- 2.4 mmol.l-1), [Ca2+] (10.4 +/- 1.67 to 4.1 +/- 0.44 mmol.l-1), [Mg2+] (0.94 +/- 0.137 to 0.17 +/- 0.032 mmol.l-1), [Cl-] (71 +/- 9.2 to 45 +/- 6.0 mmol.l-1), [urea] (9.3 +/- 0.79 to 5.1 +/- 0.54 mmol.l-1), H+ activity (29 +/- 1.6 to 17 +/- 1.6 nEq.l-1) and amylase activity (251 +/- 57.4 to 92 +/- 23.3 mu kat.l-1) were negatively correlated with flow. Both concentration and osmolality fell with increasing flow at the lower end of the flow range but osmolality always increased again by maximal flow whereas the relation between protein and flow was not consistent at the higher levels of flow and stimulation. Salivary [PO4(3+)] was not correlated with flow and at 3-14% of the plasma concentration was extremely low.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1981

The distribution of SCEs within and between the genomes of an interspecific hybrid.

The distribution of sister chromatid exchanges has been examined in the chromosomes of a hybrid male wallaby (Macropus rufogriseus female x Wallabia bicolor male), and in the X chromosomes of M. parryi and M. rufus. Comparisons were made of SCE frequency between the two genomes of the hybrid, only one of which has an appreciable amount of constitutive heterochromatin, and between he euchromatic and heterochromatic regions of the M. rufogriseus genome. The frequency of SCEs is closely correlated with the DNA content of the individual chromosomes. The distribution of the SCEs between the euchromatin and heterochromatin in the M. rufogriseus genome showed a deficiency of SCEs observed in the heterochromatin compared with the euchromatin. - A substantial excess of SCEs occurred at the nucleolar organiser region of the M. rufogriseus X chromosome. This excess was absent from the nucleolar organiser region of the X chromosome of the two other macropodine species studied and is accounted for by the presence of an adjacent euchromatin-heterochromatin junction.

Animals↗
PubMed1980

Adiaspiromycosis in Tasmanian wombats?

The finding of small spherules in the lungs of two species of wombats from Tasmania is described. An histological examination of lung tissue caused adiaspiromycosis to be suspected and the etiological agent was thought to Chrysosporium parvum.

Animals↗
PubMed1975

Inheritance of erythrocyte glucose 6-phosphate dehydrogenase in the red-necked wallaby, Macropus rufogriseus (Desmarest), consistent with paternal X inactivation.

Data are presented on a polymorphism for erythrocyte glucose 6-phosphate dehydrogenase (G6PD) in a kangaroo species. Only one of the two alleles is expressed in any individual regardless of its sex. Population and breeding data are consistent with the hypothesis of X linkage of the locus, with the paternally derived X chromosome being inactive in erythroblasts of females.

Alleles↗
PubMed1975

On the specificity of the histochemical technique for sarcoplasmic reticular adenosine triphosphatase: a light and electron microscopic study.

The specificity of the histochemical localization of the calcium activated adenosine triphosphatase (ATPase) activity of the sarcoplasmic reticulum (SR) at pH 7.4 was studied using a calcium-citro-phosphate technique. The latter involves the splitting of ATP by ATPase producing phosphate ions which then react with calcium and citrate to form an insoluble reaction product. This reaction product was detected by both light and electron microscopy. Light microscopic examination showed a darkly stained continuous reticular pattern of reaction product which surrounded individual myofibrils. This reticular pattern of reaction product was distinctly dissimilar to that found when the histochemical reactions for mitochondrial or myofibrillar ATPase were performed. Ultrastructural investigations demonstrated the presence of discrete foci of electron dense reaction product in close association with the membranes of the SR in striated muscle fibres. Only occasional flecks were seen in the vicinity of mitochondria or myofilaments. The possibility is considered that the reticular pattern of staining achieved by the calcium-citro-phosphate technique may reflect the distribution of the "extra ATPase" of the SR, an enzyme implicated in the process of calcium uptake and muscle relaxation.

Adenosine Triphosphatases↗