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Professor Karl Swann

Professor Karl Swann


School of Biosciences

+44 292087 9009
Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX


I am interested in cell signalling and metabolism during animal fertilization and early embryo development.  I use live cell imaging methods including those based on fluorescence and chemiluminescence.

Selected projects are:

1. The role and mechanism of action of PLCzeta in causing Ca2+ oscillation in eggs at fertilization

2. The relationship between Ca2+ and mitochondrial ATP production in eggs

3. Lipid droplets and lipid metabolism in eggs and early embryos using CARS microscopy


  • Deputy Module Leader and teaching on BI2331 Physiology
  • Teaching on BI2231 Cell Biology
  • Supervision of projects for Final Year Undergraduate and Masters students
  • Chair of School Research Ethics Committee


I completed my BSc Degree and the PhD in the Physiology Department at UCL under the supervision of Michael Whitaker. I worked as a postdoc in Japan with Shun-ichi Miyazaki studying Ca2+ oscillations at fertilization in eggs and returned to London to work with David Whittingham at St George’s Hospital Medical School. In 1994 I was appointed as a lecturer in the Department of Anatomy and Developmental Biology at UCL. Then in 2004 I was appointed as the Chair of Reproductive Cell Biology in the School of Medicine at Cardiff University. In 2016 I moved to the School of Biosciences. I hold an HFEA Research Licence to study human egg activation and I am an Editorial Board Member of the journal ‘Reproduction’. I have presented my research at many international meetings including invited talks at five Gordon Research Conferences.

In the 1990s I first described the existence of a soluble sperm protein that could trigger Ca2+ oscillations in mammalian eggs. I pioneered the theory that the sperm activates the egg by introducing a soluble sperm protein after gamete fusion. This mechanism of egg activation is now widely recognized as the way the sperm causes egg activation and initiates development. Work in my lab first showed that the principal mammalian sperm factor is a phospholipase C (PLC). Then in collaboration with Tony Lai at Cardiff University I helped demonstrate that the factor is a PLCzeta.  I continue to work on egg activation and aspects of mitochondrial metabolism in mammalian eggs.




















A major theme in my research is to answer the fundamental question of how the sperm activates the egg at fertilization. At fertilization in all mammals the sperm initiates development by causing a series of oscillations in the cytosolic Ca2+ concentration.  We have previously shown that the sperm initiates Ca2+ oscillations in egg by introducing the sperm specific phospholipase C zeta (PLCzeta) after gamete membrane fusion. PLCzeta generates cycles of InsP3 production and Ca2+ release.  We have shown that PLCzeta is unique amongst mammalian PLCs in causing Ca2+ oscillations in eggs, and in that it specifically targets intracellular vesicles containing phosphoinositides.  Recent studies in mice suggest that there may be an additional factor that promotes Ca2+ oscillations in eggs and we have begun to investigate the nature of a putative second sperm factor.

We are currently investigating exactly how PLCzeta causes Ca2+ release and what factors in the egg effect the sensitivity to PLCzeta.  We study egg activation in mouse eggs and collaborate with the Wales Fertility Institute to study Ca2+ oscillations in human eggs. I also collaborate with Thomas Woolley and Katerina Kaouri in the School of Mathematics in Cardiff University to model the mechanisms of Ca2+ oscillations. One of the main aims of these projects is to establish methods for improving egg activation and subsequent embryo development in clinical IVF treatments.

I am also interested in metabolism in eggs and early embryos and specifically in the regulation of mitochondrial activity.  I collaborate with Paola Borri and Wolfgang Langbein (Physics, Cardiff University) and use CARS imaging of eggs and embryos to monitor changes in lipid droplets caused by exposure to fatty acids. We study the way in which lipid content effects egg and embryo physiology. We also study the mechanism and function of sperm induced mitochondrial ATP production at fertilization.


Prof Paola Borri - Cardiff University

Thomas Woolley - Cardiff University

Dr Paul Knaggs - Wales Fertility Institute

Current Lab Members

Dr Yisu Wang (postdoc)

Miss Cindy Ikie (PhD student)

Areas of expertise

External profiles

Research links