Dr S Morley, Prof L Peck, Prof P Smith
No more applications being accepted
Competition Funded PhD Project (UK Students Only)
About the Project
Recent research has demonstrated that the relationship between muscle performance and temperature for isometric contraction in limpets has a very different form from the expected rate/temperature (R/T) curve for most biological processes (Morley et al. 2012). Most processes (e.g. metabolism) have a bell shaped curve with an optimum temperature, areas of decline on either side to levels where failure occurs. For limpet tenacity the relationship is one with a generally level response across a temperature range with sharp declines on either side. R/T curves are the standard way of assessing animal responses to temperature and are being used to quantify and predict likely impacts of climate change on animals (e.g. Deutsch et al. 2015). A very different R/T curve for an essential biological function indicates different underlying mechanisms and also different predictions of impacts of changing environments. This project will investigate temperature effects on isometric muscle contraction performance in a range of species to evaluate the generality of the limpet finding. It will also investigate the underlying mechanisms giving this difference in response.
Methodology:
1. Evaluating temperature effects on isometric muscle contraction across species: A force will be applied to a limpet attached to the substratum and the time taken for the animal to lose contact noted for different temperatures (Morley et al. 2012). In this project we will extend this approach to other gastropod molluscs species (e.g. abalones), to bivalve molluscs, echinoderms and articulated brachiopods.
2. Identifying mechanisms dictating limits to isotonic muscle performance. Experiments will be performed to directly measure metabolic process during isometric contractions using an ultramicro-oxygen electrode operating in a modulation format (Smith et al. 2007). This will provide a direct analysis of mitochondrial performance under different temperature and mechanical loads, providing insights into possible changes in mitochondrial efficiency, as already described for neuronal performance (Alavian et al. 2011). Samples may also be taken after rapid freezing for biochemical analyses and/or transmission electron microscopy to evaluate muscle contractile fibre state. Contingent on funding this project may involve comparative physiological experiments in Antarctica, New Zealand or Singapore comparing cold adapted species with related taxa from temperate and tropical latitudes.
The SPITFIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at both the British Antarctic Survey and the University of Southampton. Specific training will
include:
• Animal husbandry
• Temperature controlled whole animal physiology
• Use of ultramicro-oxygen electrodes to measure mitochondrial performance
• Electron microscopy
• Tissue biochemistry analytical methods
• Statistical analysis of global physiological patterns
References
Morley SA et al. (2012) Thermal Reaction Norms and the Scale of Temperature
Variation: Latitudinal Vulnerability of Intertidal Nacellid Limpets to Climate ChangePLoS One 7(12): e52818
Deutsch et al. (2015) Impacts of climate warming on terrestrial ectotherms across latitude Science 348: 6239, 1132-1135.
Smith et al. (2007) Principles, Development and Applications of Self-Referencing Electrochemical Microelectrodes to the Determination of Fluxes at Cell Membranes. In: Methods and New Frontiers in Neuroscience. Ed. Adrian C. Michael. CRC Press. Chapter 18
Alavian et al. (2011) Bcl-xL regulates metabolic efficiency of neurons through interaction with the mitochondrial F1FO ATP synthase. Nature Cell Biology 13: 1224-1233.