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Exposure of the yeast Saccharomyces cerevisiae to hypertonic solutions of non-permeating compounds resulted in cell shrinkage, without plasmolysis. The relationship between cell volume and osmolality was non-linear; between 1 and 4 osM there was a plateau in cell volume, with apparently a resistance to further shrinkage; beyond 4 osM cell volume was reduced(More)
Effective anthelmintics are valuable tools for biologists conducting manipulative field experiments to examine effects of parasites on wildlife. However, before such experiments are carried out the efficacy of these drugs must be determined. We conducted three field experiments (May 2010-September 2011) on free-ranging eastern grey kangaroos (Macropus(More)
The changes in morphology of Penicillium expansum Link and Phytophthora nicotianae Van Breda de Haan during freezing and thawing in a growth medium with and without the cryoprotective additive glycerol were examined with a light microscope fitted with a temperature-controlled stage. Viability of 0.5-1.0 mm diameter colonies of both fungi was determined(More)
Significantly elevated bone fluoride concentrations have been reported in a population of eastern grey kangaroos (Macropus giganteus) resident near a fluoride-emitting aluminum smelter in southeastern Australia. This paper describes the skeletal and synovial joint lesions observed post mortem in the same sample of kangaroos (n = 76). The prevalence and(More)
Non-lethal management techniques are needed for overabundant captive and wild populations of macropodid marsupials for which lethal techniques are considered inappropriate and may be hazardous. The tammar wallaby, Macropus eugenii, was used as a model species to investigate the effect of s.c. levonorgestrel implants on reproduction during breeding and(More)
Lactation is the most energetically expensive component of reproduction in mammals. Theory predicts that reproducing females will adjust their behaviour to compensate for increased nutritional demands. However, experimental tests are required, since comparisons of the behaviour of naturally reproducing and non-reproducing females cannot distinguish between(More)
Cryoinjury in individual ram spermatozoa was investigated in cells cooled at 10 degrees C/min on a programmable cryomicroscope. In physiological buffer and cryoprotective media, there was a smooth decline in sperm swimming speed with decreasing temperature; cooling in buffer caused a marked decline in the proportion of cells displaying forward progression,(More)
The Trivers-Willard hypothesis predicts that, in polygynous and sexually dimorphic mammals, mothers able to provide a large amount of care should produce more sons. Tests of this prediction, however, have generated equivocal results, possibly because multiple factors, including environmental conditions, simultaneously influence progeny sex ratio. We tested(More)
Large mammalian herbivores are commonly infected with gastrointestinal helminths. In many host species, these helminths cause clinical disease and may trigger conspicuous mortality events. However, they may also have subclinical impacts, reducing fitness as well as causing complex changes to host growth patterns and body condition. Theoretically, juveniles(More)