Improving the growth rate and flesh quality of cultured Barramundi: Investigating the effects of temperature, diet, and population. Barramundi fillet is one of the premier seafoods available in Australia and the decline of wild fisheries has increased the demand for the cultured product. Accordingly, there has been a rapid growth of the barramundi farming industry, but competition from cheaper overseas imports has cut the sale price and profit margins of local growers. By developing methods to i ....Improving the growth rate and flesh quality of cultured Barramundi: Investigating the effects of temperature, diet, and population. Barramundi fillet is one of the premier seafoods available in Australia and the decline of wild fisheries has increased the demand for the cultured product. Accordingly, there has been a rapid growth of the barramundi farming industry, but competition from cheaper overseas imports has cut the sale price and profit margins of local growers. By developing methods to increase growth rates, this research has the potential to substantially increase profit margins by reducing production costs and increasing turnover. Improvement of flesh quality will also increase the attractiveness of barramundi fillet. Increasing the viability of barramundi culture in Australia will attract more growers and increase employment opportunities.Read moreRead less
Regulation of salt gland activity in the estuarine crocodile: phenotypic plasticity and control mechanisms. The estuarine crocodile excretes excess sodium and chloride ions through salt glands located on the tongue, enabling the crocodile to live in seawater. This study will investigate the regulation of salt gland secretory capacity and activity, by examining both the phenotypic plasticity of the gland to changes in environmental salinity and diet, and by determining the neural/humoral mech ....Regulation of salt gland activity in the estuarine crocodile: phenotypic plasticity and control mechanisms. The estuarine crocodile excretes excess sodium and chloride ions through salt glands located on the tongue, enabling the crocodile to live in seawater. This study will investigate the regulation of salt gland secretory capacity and activity, by examining both the phenotypic plasticity of the gland to changes in environmental salinity and diet, and by determining the neural/humoral mechanisms controlling secretory rate. In vivo measurements of blood flow and salt gland secretory rate, together with perfused gland preparations will reveal extrinsic and intrinsic factors controlling salt gland activity and the degree of coupling between blood flow and secretory rate.Read moreRead less
FERTILIZATION IN VIVO AND IN VITRO IN AUSTRALIAN MARSUPIALS. Using reproductive technology previously undeveloped in Australian marsupials this study addresses the most significant question still unresolved in marsupial reproductive biology - 'How does fertilization occur?' We propose to investigate the morphological and functional characteristics of fertilisation and its roles in early development in marsupials, the uniqueness of these events and their evolutionary significance. These findings ....FERTILIZATION IN VIVO AND IN VITRO IN AUSTRALIAN MARSUPIALS. Using reproductive technology previously undeveloped in Australian marsupials this study addresses the most significant question still unresolved in marsupial reproductive biology - 'How does fertilization occur?' We propose to investigate the morphological and functional characteristics of fertilisation and its roles in early development in marsupials, the uniqueness of these events and their evolutionary significance. These findings will not only further our knowledge of reproduction in marsupials and shed light on the evolutionary factors underlying sperm and egg design but will provide tools for assisted breeding programs for threatened wildlife and for the regulation of over abundant species.Read moreRead less
A contractile cochlear frame - a possible new mechanism of sound adaptation. It is generally accepted that the rigid frame that harbours sensory structures in the hearing organs of modern higher vertebrates has only a passive supporting role. We have discovered a contractile component in the cartilaginous cochlear frame of the lizard Teratoscincus scincus and demonstrated that the tonus of the contractile tissue can be regulated. We hypothesize a new, previously unknown mechanism of slow mechani ....A contractile cochlear frame - a possible new mechanism of sound adaptation. It is generally accepted that the rigid frame that harbours sensory structures in the hearing organs of modern higher vertebrates has only a passive supporting role. We have discovered a contractile component in the cartilaginous cochlear frame of the lizard Teratoscincus scincus and demonstrated that the tonus of the contractile tissue can be regulated. We hypothesize a new, previously unknown mechanism of slow mechanical adaptation in the vertebrate hearing organ. The aim of the proposed project is to examine this hypothesis in more detail.
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The co-expression of visual pigments in a single photoreceptor: environmental regulation and spectral tuning. The light sensitive cells (photoreceptors) in the vertebrate retina contain filters (oil droplets) and visual pigments (opsins). These structures tune the incoming light and initiate the visual process, respectively. Exciting new research reveals that some vertebrates express more than one opsin within a single photoreceptor. We plan to examine the regulation of single and two co-express ....The co-expression of visual pigments in a single photoreceptor: environmental regulation and spectral tuning. The light sensitive cells (photoreceptors) in the vertebrate retina contain filters (oil droplets) and visual pigments (opsins). These structures tune the incoming light and initiate the visual process, respectively. Exciting new research reveals that some vertebrates express more than one opsin within a single photoreceptor. We plan to examine the regulation of single and two co-expressed opsin genes by manipulating the light environment. We expect to determine the environmental triggers for visual pigment tuning and the effects of co-expression on colour vision.Read moreRead less
Environmental regulation of opsin expression and spectral tuning in the vertebrate retina. Exciting new evidence shows that the vertebrate visual system is extraordinarily plastic and that the colour and brightness of the ambient light regulates both the spatial and temporal expression of visual pigments (opsin) genes and the degree of spectral filtering in the retina. Based on findings that more than one visual pigment can be co-expressed in a single photoreceptor type, we plan to manipulate th ....Environmental regulation of opsin expression and spectral tuning in the vertebrate retina. Exciting new evidence shows that the vertebrate visual system is extraordinarily plastic and that the colour and brightness of the ambient light regulates both the spatial and temporal expression of visual pigments (opsin) genes and the degree of spectral filtering in the retina. Based on findings that more than one visual pigment can be co-expressed in a single photoreceptor type, we plan to manipulate the light environment in order to identify and quantify the effect of different lighting regimes by morphological, spectral and molecular techniques in a concerted effort to understand the regulation of opsin expression.Read moreRead less
The evolution of colour vision in vertebrates. Colour vision plays a crucial role in the lives of many animals including vertebrates. However, very little is known about the origins of colour vision and we aim to fill this gap. Photoreceptors (cone cells) with sensitivities to different colours mediate colour vision (humans possess blue, green and red cones). This study will examine the structure, physiological responses and molecular biology of these cells in the closest living relatives of the ....The evolution of colour vision in vertebrates. Colour vision plays a crucial role in the lives of many animals including vertebrates. However, very little is known about the origins of colour vision and we aim to fill this gap. Photoreceptors (cone cells) with sensitivities to different colours mediate colour vision (humans possess blue, green and red cones). This study will examine the structure, physiological responses and molecular biology of these cells in the closest living relatives of the early vertebrates. The underlying mechanisms for spectral tuning, the genetic rate of evolutionary change and the importance of colour in visual ecology will also be examined.Read moreRead less
What's bred in bone: effects of thyroid hormone supplementation on bone growth and remodelling in ectotherms and endotherms. Influence of resting metabolic rate (RMR) and exercise activity on bone microstructure is investigated in a variety of amniote taxa. By varying the dose of supplemental triiodothyronine (T3), ectotherms are made hyperthyroid with elevated RMR, and endotherms - hypothyroid with depressed RMR. Effects of T3 are compared against those of mechanical loading, in form of increa ....What's bred in bone: effects of thyroid hormone supplementation on bone growth and remodelling in ectotherms and endotherms. Influence of resting metabolic rate (RMR) and exercise activity on bone microstructure is investigated in a variety of amniote taxa. By varying the dose of supplemental triiodothyronine (T3), ectotherms are made hyperthyroid with elevated RMR, and endotherms - hypothyroid with depressed RMR. Effects of T3 are compared against those of mechanical loading, in form of increased daily treadmill exercise. Rates of bone growth and secondary remodelling are determined by histological analysis, and correlated with T3 and bone strain levels. The study tests the hypothesis that evolution of endothermy can be inferred from bone microstructure of fossil bones.Read moreRead less