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Miss Catrin Williams 

Supervisors: Dr. Jo Cable, Prof. David Lloyd, Dr. Mike Coogan (Chemistry) and Dr. David Williams (CASE partner,Neem Biotech Ltd).

PhD Funding: EPSRC CASE studentship (EP/H501118/1)

Spironucleus vortens is a parasite of huge economic importance in the aquaculture industry, particularly of ornamental fish such as cichlids, worth an estimated $7000 million per annum. Fish infected with this parasite display the characteristic clinical manifestations of holes in the head and lateral line region, often resulting in 100% mortality. Treatment with the nitroimidazole metronidazole is the traditional method used to eradicate S. vortens infections, however in recent years its use has been highly controversial due to carcinogenicity and its non-biodegradable properties, prompting its ban from use on outdoor fish farms in 1998. Evidently, there is an urgent need for alternative therapies to treat this troublesome parasite.

two-photon confocal microscopic image

Fig. 2. A two-photon confocal microscopic image of S. vortens trophozoites, stained with ruthenium nanoparticles.

The medicinal properties of garlic have been known for millennia with ancient civilisations such as the Sumarians, Egyptians, Grecians and Romans applying its healing powers to a range of common ailments such as asthma, convulsions, snake bites and circulatory problems. During the Black Plague a treatment containing garlic was used to ward off the infection, indicating its possible antimicrobial properties. It wasn’t until the mid 20th century did scientists begin to research these antimicrobial properties of garlic. This coincided with the surge in antibiotic resistance amongst pathogens seen in this era prompting researchers to look for alternative therapies to combat disease.

In recent years, garlic’s medicinal properties have been highly studied with, as yet, no reports of microbial resistance. However, the mode of action of this chemically complex extract remains a mystery.

Project aims:

  • Evaluate the antimicrobial effect of garlic and its isolated compounds against S. vortens.
  • Investigate the mode of action of garlic against this parasite.
  • Uncover more about the biochemistry and pathogenicity of this parasite.

Other areas of interest:

  • In vitro culturing techniques of the ciliated parasite Ichthyophthirius multifillis, the causative agent of whitespot disease in freshwater fish.
  • Investigating the antimicrobial effect of garlic against two clinically important pathogenic bacteria, Clostridium difficile and Campylobacter jejuni
  • Evaluating the toxicity levels of garlic on fish.
Spironucleus vortens heat maps, imaged by DIC microscopy

Fig. 3. Spironucleus vortens heat maps, imaged by DIC microscopy


  • Dr. Andy Shinn – The Institute of Aquaculture, Stirling University, Scotland. In vitro culture of I. multifiliis.
  • Dr. David Leitsch –Department of Specific Prophylaxis and Tropical Medicine, Centre for Physiology. Pathophysiology and Immunology, Medical University of Vienna, Austria. Proteomic analysis of S. vortens.
  • Prof. Les Baillie – School of Pharmacy, Cardiff University. Antimicrobial effect of garlic against Clostridium difficile.
  • Dr. Miguel Aon - Institute of Molecular Cardiobiology, Johns Hopkins University, Baltimore, USA. Redox dynamics of Spironucleus vortens.
  • Dr. Nigel Yarlett - Haskins Laboratories, Pace University, New York City, USA. Antioxidant system of Spironucleus vortens.
  • Dr. G. Krishnamoorthy - Dept. Chem. Sci., Tata Institute of Fundamental Research, Mumbai, India.
  • Dr Anthony Hayes – Confocal Microscopy Unit, School of Biosciences, Cardiff University.
  • Mr Nick White - Vision Science Bioimaging Labs, School of Optometry and Vision Sciences, Cardiff University.

 Research visits:

  •  Institute of Aquaculture, Stirling Univeristy (12th-19th January, 2010). My visit was hosted by Dr. Andy Shinn, where I investigated methods of culturing the protozoan ciliate Ichthyophthirius multifiliis (Ich), which causes whitespot disease in fish.
  • Department of Specific Prophylaxis and Tropical Medicine in the Centre for Physiology, Pathophysiology and Immunology at the Medical University of Vienna, Austria (1st-15th August, 2010). My visit was hosted by Dr. David Leitsch from whom I acquired new proteomic methods to investigate the mode of action of metronidazole and garlic-derived compounds against Spironucleus vortens.
  • Institute of Molecular Cardiobiology, Johns Hopkins University, Baltimore, USA (30th March-12th April, 2011). My visit was hosted by Dr. Miguel A. Aon. Here I employed novel spectrofluorimetric and imaging techniques, developed by Dr. Aon for cardiomyocytes, to investigate the effects of inhibitors on the redox dynamics of S. vortens.
  • Haskins Laboratories, Pace University, New York City, USA (12th-28th April, 2011). My visit was hosted by Dr. Nigel Yarlett. During my visit, I used HPLC to characterise the non-protein thiol antioxidant system of S. vortens, before and after treatment with inhibitors.

Successful grant applications:

  • The Gillian Powell Memorial Travel Scholarship Award (2009)
  • The Journal of Experimental Biology Travelling Fellowship (2010)
  • ISOP Meeting Travel Award for Students and Postdocs (2010)
  • Welsh Livery Guild Travel Scholarship (2010)
  • The Charles Coles Travelling Scholarship (2011)