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Faculty of Health and Life Sciences

 Christopher Mitchell

Christopher Mitchell

Experimental officer

 C.Mitchell3@exeter.ac.uk

 Environment and Sustainability Institute 

 

Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, UK


Overview

I started my career at the University of Exeter in 2006 as a Research Technician for Prof. John Hunt, and was responsible for the chemical analysis of insect pheromones and cuticular hydrocarbons using GCMS. I then moved on to a position with Profs Michael Cant and Jon Blount, which involved the analysis of a range of markers of oxidative stress in banded mongooses using HPLC and plate assays.

In 2013 I moved to the Hawkesbury Institute for the Environment, Western Sydney University, where I was responsible for the operation of a range of instruments including GCMS, HPLC, XRF, UV-vis spectroscopy and TOC analysers, analysing a range of sample types including greenhouse gases, soils, plants and animal samples.

I rejoined the University of Exeter in 2018 as an Experimental Officer, managing the stable isotope facility within the ESI and the metabolomics laboratory within the CEC.

The stable isotope facility is equipped with two continuous flow isotope ratio mass spectrometry instruments. We have a Sercon Integra 2 system, which is dedicated to the analysis of 13C and 15N in solid organic samples. We also have a Sercon 20-22 isotope ratio mass spectrometer which is equipped with  a Europa EA-GSL sample preparation system, a high temperature pyrolysis furnace and a CETAC autosampler for gas samples. This is an extremely versatile instrument that is capable of analysing 13C, 15N, 18O and D in solid samples as well as 13C and 18O in gases or carbonate samples.

The Metabolomics laboratory is equipped with an Agilent 7890 gas chromatograph coupled with a 5975 single quad mass spectrometer, fitted with a CTC autosampler to allow the analysis of a range of compounds, and allowing for automated liquid, gas or SPME injections. Common applications include the analysis of insect pheromones, cuticular hydrocarbons and chemical defence compounds, and amino acid analysis.

The laboratory also houses an Agilent 1200 series HPLC equipped with a diode array detector, fluorescence detector and single quad mass spectrometer. This system is commonly used for quantifying markers of oxidative stress, vitamin E, and carotenoids in a range of sample types.

We also have a Molecular Devices Spectramax M2 plate reader which is routinely used for a range of assays measuring markers of oxidative stress.

Publications

  • H.C. Heyworth, P. Pokharel, J.D. Blount, C. Mitchell, G. Petschenka, H.M. Rowland (2023) Antioxidant availability trades off with warning signals and toxin sequestration in the large milkweed bug (Oncopeltus fasciatus). Ecology and Evolution 13(4), e9971
  • J.D. Blount, H.M. Rowland, C. Mitchell, M.P. Speed, G.D. Ruxton, J.A. Endler, L.P. Brower (2023) The price of defence: toxins, visual signals and oxidative state in an aposematic butterfly. Proceedings of the Royal Society B 290 (1991), 20222068
  • Z.E. Melvin, H. Dhirani, C. Mitchell, T.R.B. Davenport, J.D. Blount, A.V. Georgiev (2022) Methodological confounds of measuring urinary oxidative stress in wild animals. Ecology and Evolution 12(7), e9115
  • D. Egli, K.J. Harvey, B.D. Moore, C. Mitchell, T. Olckers (2022) Variations in chemical defences and patterns of natural enemy attack between native and introduced populations of fireweed (Senecio madagascariensis): Impications for biological control. Austral Ecology 47(2), 428-439
  • M. Meniri, E.Evans, F.J. Thompson, H.H. Marshall, H.J. Nichols, G. Lewis, L. Holt, E. Davey, C. Mitchell, R.A. Johnstone, M.A. Cant, J.D. Blount (2022) Untangling the oxidative cost of reproduction: An analysis in wild banded mongooses. Ecology and Evolution 12(3), e8644
  • S.F. Allen, F. Ellis, C. Mitchell, X. Wang, N. J. Boogert, C.Y. Lin, J. Clokey, K.V. Thomas, J.D. Blount (2021) Phthalate diversity in eggs and associations with oxidative stress in the European herring gull (Larus argentatus). Marine Pollution Bulletin 169, 112564
  • P.J. Jacobs, M.K. Oosthuize, C. Mitchell, J.D. Blount, N.C. Bennett (2021) Oxidative stress in response to heat stress in wild caught Namaqua rock mice, Micaelamys namaquensis. Journal of Thermal Biology 98, 102958
  • F. Rendell-Bhati, P. Paganos, A. Pouch, C. Mitchell, S. D'Aniello, B.J. Godley, K. Pazdro, M.I. Arnone, E. Jimenez-Guri (2021) Developmental toxicity of plastic leachates on the sea urchin Paracentrotus lividus. Environmental Pollution 269, 115744
  • P.J. Jacobs, M.K. Oosthuize, C. Mitchell, J.D. Blount, N.C. Bennett (2020) Heat and dehydration induced oxidative damage and antioxidant defences following incubator heat stress and a simulated heat wave in wild caught four-striped mice Rhabdomys dilectus. PloS one 15(11), e0242279
  • C. Deveautour, J. Chieppa, U.N. Nielson, M.M. Boer, C. Mitchell, S. Horn, S.A. Power, A. Guillen, A.E. Bennett, J.R. Powell (2020) Biogeography of arbuscular mycorrhizal fungal spore traits along an aridity gradient and responses to rainfall manipulation. Fungal Ecology 46, 10899
  • P.A. Moran, J. Hunt, C. Mitchell, M.G. Ritchie, N.W. Bailey (2020) Sexual selection and population divergence III: Interspecific and intraspecific variation in mating signals. Journal of Evolutionary Biology 33(7), 990-1005
  • C. Marschner, M.B. Krockenberger, D.P. Higgins, C. Mitchell, B.D. Moore (2019) Ingestion and Absorption of Eucalypt Monoterpenes in the specialist feeder, the Koala (Phascolarctos cinereus). Journal of Chemical Ecology, 45(9)                                                   
  •  K.L. Brice, P. Trivedi, T.C. Jeffries, M.D.J. Blyton, C, Mitchell, B.K. Singh, B.D. Moore (2019) The Koala (Phascolarctos cinereus) faecal microbiome differs with diet in a wild population. PeerJ, 7
  • E.I.K. Vitikainen, M. Cant, J.L. Sanderson, C. Mitchell, H.J. Nichols, H.H. Marshall, F.J. Thompson, J.S. Gilchrist, S. Hodge (2016) Evidence of oxidative shielding in a wild mammal. Frontiers in Ecology and Evolution, 4:58
  • J. Plett, K. Plett. S. Bithell, C. Mitchell, K. Moore, J. Powell, I. Anderson (2016) Improved Phytophthora resistance in commercial chickpea (Cicer arietinum) varieties negatively impacts symbiotic gene signalling and symbiotic potential in some varieties. Plant, Cell and Environment, 39(8):1858-69
  • S.Pascoal, M. Mendrok, C. Mitchell, A.J. Wilson, J. Hunt, N.W. Bailey (2015) Sexual selection and population divergene I. The influence of socially flexible cuticular hydrocarbon expression in male field crickets (Teleogryllus oeanicus). Evolution, 70(1):82-87
  • D. Newcombe, J. Hunt,C. Mitchell, A. Moore (2015) Maternal effects and maternal selection arising from variation in allocation of free amino acid to eggs. Ecology and Evolution, 5(12):2397-2410
  • S. Lane, J.H. Solino,  C. Mitchell, J. Blount,  K. Okada, J. Hunt, C. House (2015) Rival male chemical cues evoke changes in male pre- and post-copulatory investment in a flour beetle. Behavioural Ecology
  • A.E. Winters, M.Stevens, C. Mitchell, S.P. Blomberg, J.D. Blount (2014) Maternal effects and warning signal honesty in eggs and offspring of an aposematic ladybird beetle. Functional Ecology, 28:1187-1196
  • S. Steiger, G.D. Ower, J. Stokl, C. Mitchell, J. Hunt, S.K. Sakaluk (2013) Sexual selection of cuticular hydrocarbons on male sagebrush crickets in the wild. Proc. R. Soc. B. 280: 20132353
  • C. Weddle,  S. Steiger, C. Hamaker, G. Ower, C. Mitchell, S.K. Sakaluk, J. Hunt (2013) Cuticular hydrocarbons as a basis for chemosensory self-referencing in crickets: a universal mechanism facilitating polyandry in insects. Ecology letters,  Mar;16(3):346-53
  • D. Newcombe, J.D. Blount, C. Mitchell, A.J. Moore (2013) Chemical egg defence in the large milkweed bug, Oncopeltus fasciatus, derives from maternal but not paternal diet. Entomologia Experimentalis et Applicata, 149:197-205
  • M.D. Sharma, C. Mitchell, J. Hunt, T. Tregenza, and D.J. Hosken (2012) The Genetics of Cuticular Hydrocarbon Profiles in the Fruit Fly Drosophila simulans. J. Hered. 103:230-239
  • S.N. Gershman, C. Mitchell, S.K. Sakaluk, J. Hunt (2012) Biting off more than you can chew: sexual selection on the free amino acid composition of the spermatophylax in decorated crickets. Proc Biol Sci. Jul 7;279(1738):2531-8
  • C. B. Weddle, C. Mitchell, S.K. Bay, S.K. Sakaluk, and J. Hunt (2012)  Sex-specific genotype-by-environment interactions for cuticular hydrocarbon expression in decorated crickets, Gryllodes sigillatus: implications for the evolution of signal reliability. Journal of Evolutionary Biology, 25: 2112–2125
  • J. Hunt, R.R Snook, C. Mitchell, H.S Crudgington,  and A.J. Moore (2012) Sexual selection and experimental evolution of chemical signals in Drosophila pseudoobscura. Journal of Evolutionary Biology, 25(11): 2232-2241

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Publications

Journal articles

Rendell-Bhatti F, Paganos P, Pouch A, Mitchell C, D’Aniello S, Godley BJ, Pazdro K, Arnone MI, Jimenez-Guri E (2021). Developmental toxicity of plastic leachates on the sea urchin Paracentrotus lividus. Environmental Pollution, 269, 115744-115744.

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