Dr Jackie Parry
Division of Biomedical and Life Sciences
Faculty of Health and Medicine
Tel: +44 1524 593489
Fax: +44 1524 593192
Research is concerned with studying the interactions between protozoa and their prey in freshwater systems; both in the plankton and also within biofilms. Firstly, a new method has been developed for the determination of protozoan grazing rates. It employs the use of a GFP-expressing bacterium which when ingested by protozoa, loses its fluorescence due to the low pH of the food vacuoles. This loss of fluorescence over time is monitored by an automated fluorescence plate reader. The method is currenlty being tested for both laboratory and field applications and has also been adapted to produce a method for determining protozoan grazing rates on attached prey, in order to study the potential grazing impact on biofilms.
The role of protozoa in biofilms remains unclear, compared with the pretty clear insight we have on their role in the plankton. However our work has already shown that these predators are present in natural biofilms throughout the year and that there is a significant positive relationship between them (particularly heterotrophic flagellates) and bacteria. The overall aim of our work is to achieve a better understanding of biofilm development and stability in situ, in order to (i) propose realistic methods for their control (industrial interest), (ii) to evaluate their overall contribution to freshwater carbon dynamics (ecological interest) and (iii) to assess the extent to which they harbour pathogens (biomedical interest). Work is currently focussing on protozoan succession during colonisation of virgin substrata, whether bacterial cell type on the surface affects this and the strength by which protozoa can adhere to surfaces, using flow cells and video microscopy. We are also examining the fate of ingested bacteria within the protozoa i.e. are they digested, do they pass straight through or do they replicate within, as this has implications for the harbouring and spread of potentially pathogenic bacteria in the environment (funded by The Wellcome Trust).
Research on planktonic interactions is directed at protozoan interaction with picocyanobacteria. These are photosynthetic bacteria that bear no morphologically distinguishing features and thus only two genera have so far been described. However, this is like classifying all heterotrophic bacteria into two genera, which is unrealistic. In light of this, a rapid and cost effective method with which to differentiate between strains of picocyanobacteria was developed at Lancaster (funded by The Leverhulme Trust). The method is a molecular typing technique that groups picocyanobacterial isolates into genetically similar ‘types’. Its use in field experiments showed there to be many ‘types’ of picocyanobacteria in Esthwaite water (Cumbria) and that these ‘types’ appeared at different times of the year. A recently awarded NERC grant will examine whether these ‘types’ are ecologically different by assessing their growth requirements and susceptibility to protozoan grazing, particularly by mixotrophic dinoflagellates.
1987 B.Sc. (Hons), Applied Biology, Liverpool Polytechnic
1990 Ph.D., Soil Microbiology, Liverpool University
1990-93 Post Doctoral Research Assistant, University of Birmingham
1993-Lecturer, Lancaster University
Montagnes, DJS, Barbosa, AB, Boenigk, J, Davidson, K, Jürgens, K, Macek, M, Parry, JD, Roberts, EC and Šimek, K (2008) Selective feeding behaviour of key free-living protists: avenues for continued study. Aquatic Microbial Ecology, (in press)
Dillon, AM and Parry JD (2008) Isolation and characterization of temperate phage infecting freshwater phycocyanin-rich Synechococcus species. Freshwater Biology, 53: 1253-1261.
Parry, JD, Holmes, AK, Unwin, ME and Laybourn-Parry J (2007) The use of ultrasonic imaging to evaluate the effect of protozoan grazing and movement on the topography of biofilm. Letters in Applied Microbiology, 45: 364-370.
Pickup, Z, Pickup, R and Parry, JD (2007) Growth of Acanthamoeba castellanii and Hartmannella vermiformis on live, heat-killed and DTAF-stained bacterial prey. FEMS Microbiology Ecology 61: 264-272.
Pickup, Z, Pickup, R and Parry, JD (2007) Effects of bacterial prey species and their concentration on the growth of the amoebae Acanthamoeba castellanii and Hartmannella vermiformis. Applied and Environmental Microbiology 73: 2631- 2634.
Pickup, Z, Pickup, R and Parry, JD (2007) A comparison of the growth and starvation responses of Acanthamoeba castellanii and Hartmannella vermiformis in the presence of suspended and attached Escherichia coli K12. FEMS Microbiology Ecology 59: 556-563.
Holmes, AK, Laybourn-Parry, J, Parry, JD, Unwin, ME and Challis, R (2006) Ultrasonic imaging of biofilms utilizing echoes from the biofilm/air interface. IEEE Trans UFFC, 53: 185-192.
Parry, JD. (2005) Sugar-coated bacteria – sheep in wolves’ clothing? Microbiology Today, 32: 18-21.
Parry, JD (2004) Protozoan grazing of freshwater biofilms: Invited Review. Advances in Applied Microbiology 54: 167-196.
Boucard, TK, Parry, JD, Jones, K & Semple, KT (2004) Effects of organophosphate and synthetic pyrethroid sheep dip formulations on protozoan survival and bacterial survival and growth. FEMS Microbiology Ecology 47:121-127
Hunt, A.P., Hamilton-Taylor, J. and Parry, J.D. (2001) Trace metal interactions within epilithic biofilms in small acidic mountain streams. Archiv fur Hydrobiologie 153: 155-176.
Parry, J.D., Drinkall, J. & Hunt, A.P. (2001) The influence of free-living protozoa on aquatic biofilm dynamics. In Biofilm community interactions: Chance or necessity? (Gilbert, P., Allison, D., Brading, M., Verran, J. & Walker, J. eds.), pp 255-261. Bioline, Cardiff.
English, J., Pickup, R. & Parry, J.D. (2001) The potential harbouring of coliform bacteria by protozoa in biofilms. In Biofilm community interactions: Chance or necessity? (Gilbert, P., Allison, D., Brading, M., Verran, J. & Walker, J. eds.), pp 271-279. Bioline, Cardiff.
Heaton, K., Hunt, A.P. & Parry, J.D. (2001) Amoeboid grazing on surface-associated prey. In Biofilm community interactions: Chance or necessity? (Gilbert, P., Allison, D., Brading, M., Verran, J. & Walker, J. eds.), pp 293-301. Bioline, Cardiff.
Parry, J.D., Heaton, K., Drinkall, J. & Jones, H.L.J. (2001) The feasibility of using GFP-expressing Escherichia coli, coupled with fluorimetry, to determine protozoan ingestion rates. FEMS Microbiology Ecology 35: 11-17.
Laybourn-Parry, J.E.M. & Parry, J.D. (2000) Flagellates and the microbial loop. In, The Flagellates (Leadbeater, B.S.C. & Green, J. eds.), Taylor & Francis, London, pp.216-239.
Hunt, A.P., Parry, J.D. & Hamilton-Taylor, J. (2000). Further evidence of elemental composition as an indicator of the bioavailability of humic substances to bacteria. Limnology and Oceanography 45(1): 237-241.
Williams, S.T., Mortimer, A.M. & Parry, J.D. (1999). Phages in Soil. In Encyclopedia of Virology, Second Edition. Granoff, A. and Webster, R. (eds.). Academic Press, London.
Hunt, A.P., Parry, J.D. & Hamilton-Taylor, J. (1999). Algal-Bacterial relationships in streams with varying DOC concentration and source. In Biofilms in Aquatic Environments. Keevil, C.W., Dow, C., Godfree, A. and Holt, D (eds.). Special Publication Number 242. The Royal Society of Chemistry. Pp 252.
Hunt, A.P. & Parry, J.D. (1998). The effect of substratum roughness and river flow rate on the development of a freshwater biofilm community. Biofouling 12: 287-303.
Smith, J.K., Parry, J.D., Day, J.E. & Smith, R.J. (1998). A PCR technique based on the Hip1 interspersed repetitive sequence distinguishes cyanobacterial species and strains. Microbiology 144: 2791-2801.
Eccleston-Parry, J.D., & Leadbeater, B.S.C. (1995). The regeneration of phosphorus and nitrogen by four species of heterotrophic nanoflagellate feeding on three nutritional states of a single bacterial strain. Applied Environmental Microbiology 61: 1033-1038.
Eccleston-Parry, J.D., & Leadbeater, B.S.C. (1994). The effect of long-term low bacterial density on the growth kinetics of three marine heterotrophic nanoflagellates. Journal of Experimental Marine Biology and Ecology 177: 219-233.
Eccleston-Parry, J.D., & Leadbeater, B.S.C. (1994). A comparison of the growth kinetics of six marine heterotrophic nanoflagellates fed with one bacterial strain. Marine Ecology Progress Series 105: 167-177.