MRes - Temperature sensitivity of flight muscle mechanics in Zebra Finch

Supervisors: Dr Andrea Gaede and Dr Timothy West 

Department: Comparative Biomedical Sciences  

Project Details

What are the temperature sensitivities of force, velocity, and power in single pectoralis fibres from zebra finch (T. guttata)?  Outcomes of this study will establish novel information about key properties of flight muscle fibres from a fast-flying passerine.  

Skinned-fibre experiments highlight sarcomere- and crossbridge-level capacity for muscle power generation because they are done in the absence of (i) membrane-level activation pathways and (ii) whole-muscle structural influences, such as those of tendon behaviours and complex pennation angles.  Fibres from mammalian and avian muscles are usually studied at temperatures below normal body temperatures.  Low-temperature (12 – 25˚C) activation ensures that contraction stresses remain relatively low, compared to stresses at higher temperature, and non-damaging to the de-membranated preparation.  Hence, relating fibre-level mechanics to in vivo whole-muscle function requires prior knowledge of, or assumptions about, the temperature-sensitivity of various mechanical properties.  

We will use fibres from zebra finch pectoralis muscle and measure their passive and active contractile properties and analyse and interpret these measurements.  An ambitious aim is to generate a complete array of data (including measurement of fibre dimensions) and calculations (stresses, passive and active stiffnesses, maximum shortening speeds and peak powers) for each individual fibre at 20 ˚C and to repeat key measurements at 40 ˚C.  Working at, or near, 40 ˚C will be a novel challenge.  

Greater understanding of the temperature-sensitivities of avian flight-muscle mechanics will allow us, in future work, to conduct mechanistic studies at favourable low temperatures with stronger confidence about how single fibre properties need to be adjusted to match function at physiological temperature (40˚C).  This project also provides foundational knowledge for investigating the neural pathways associated with neuromuscular features that enable birds to fly at a range of speeds while manoeuvring through complex environments. 

References

  1. Gaede et al., 2017 “Neurons responsive to global visual motion have unique tuning properties in hummingbirds.” Current Biology 27 (2), 279-285. https://doi.org/10.1016/j.cub.2016.11.041 

  2. Curtin et al., 2015 “Skinned fibres produce the same power and force as intact fibre bundles from muscle of wild rabbits” https://doi.org/10.1242/jeb.121897 

  3. Bahlman et al., 2020 “Flight muscle power increases with strain amplitude and decreases with cycle frequency in zebra finches (Taeniopygia guttata)” J Exp Biol 223 (21): jeb225839. https://doi.org/10.1242/jeb.225839 

  4. Altshuler, et al., 2015. “The biophysics of bird flight: functional relationships integrate aerodynamics, morphology, kinematics, muscles, and sensors.” Canadian Journal of Zoology 93 (12), 961-975. https://doi.org/10.1139/cjz-2015-0103 

Requirements

Essential:

This can be taken full-time (12months FTE) project commencing in October 2024, based at RVC's Hawkshead campus. Work is performed on previously collected tissue. 

Funding

Partially funded: The lab will be covering the project costs, with the MRes student expected to meet the course fees and their living expenses. 

International applicants are welcome to apply but must be able to fund the difference between "Home" and "Overseas" tuition fees. Please note that EU/EEA and Swiss national students may no longer be eligible for the “Home” rate of tuition fees, dependent on personal circumstances (including immigration status and residence history in the UK) and UK government rules which are currently being developed. For up-to-date information on fees for EU/EEA and Swiss national students following Brexit please see our fees and funding page. 

How to Apply

For more information on the application process and English Language requirements see How to Apply.

Deadline: Sunday 14th July 2024

We welcome informal enquiries - these should be directed to agaede@rvc.ac.uk or twest@rvc.ac.uk

Interview date and location: TBC

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