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Ciliates and environmental stress

Team leader: 
Juan-Carlos Gutierrez
Team members: 
Ana Martín-González
Silvia Díaz del Toro
Maria Teresa García
Patricia de Francisco
Institute or University: 
University Complutense (UCM). Dept. Microbiology. Faculty of Biology.
Jose Antonio Novais, 12
Research interests: 

Main research line: Ciliates as eukaryotic microbial models to analyze the stress response to different  environmental stressors (mainly heavy metals). This research line includes; 1- analysis of ciliate metallothionein diversity and the elements involved in the gene expression regulation of these proteins. 2- Study of genes involved in the glutathione metabolism under oxidative stress. 3- cellular adaptation to heavy metal stress. 4- epigenetic (microRNAs) of heavy metal stress. 5- Design of cell whole biosensors for detection of metal ions in environmental samples based on metallothionein promoters from Tetrahymena thermophila. With regard to this last point, our research group have two already accepted Spanish patents (ES 2354342 B1 and ES 2353784 B1, corresponding to the constructs MTT1Luc and MTT5Luc, respectively), which correspond with both cell biosensors. Comparison with other published cell biosensors indicates that Tetrahymena metallothionein promoter-based biosensors appear to be the most sensitive eukaryotic metal biosensors and compare favourably with some prokaryotic biosensors as well. At present, MTT5 promoter is the most robust inducible promoter isolated from T. thermophila. Other secondary research lines: 1- Ciliate apoptosis induced by metals. 2- Isolation and sequencing of nanochromosomes from Sterkiella (Oxytricha) nova, using an improved End-End PCR method (by this methodology the macronuclear genome of this and other related ciliates might be largely explored).

Environmental stress
Heavy metals
Gene expression regulation
Sterkiella (Oxytricha)
Quantitative RT-PCR
Fluorescent and electron microscopy
Biolistic transformation and electroporation
Protein electrophoresis (1D and 2D)
DNA pulsed-field gel electrophoresis (OFAGE)
DNA cloning and sequencing


  • Ciliate metallothioneins: unique microbial eukaryotic heavy-metal-binder molecules. Gutiérrez, J.C., Amaro, F., Díaz, S., de Francisco, P., Cubas, L.L. & Martín-González, A. Journal of Biological Inorganic Chemistry. 16: 1025-1034. 2011.
  • Whole-cell biosensors for detection of heavy metal ions in environmental samples based on metallothionein promoters from Tetrahymena thermophila. Amaro, F., Turkewitz, AP., Martín-González, A. & Gutiérrez, JC. Microbial Biotechnol.  4: 513-522. 2011.
  • From heavy metal-binders to biosensors- Ciliate metallothioneins discussed. Gutiérrez, J.C., Amaro, F. & Martín-González, A.  BioEssays. 31: 805-816. 2009.
  • A pseudo-phytochelatin synthase in the ciliated protozoan Tetrahymena thermophila. Amaro, F., Ruotolo, R., Martín-González, A., Faccinni, A., Ottonello, S. & Gutiérrez, J.C. Comp. Biochem. Physiol. Part C.  149: 598-604. 2009.
  • Heavy metals generate reactive oxygen species in terrestrial and aquatic ciliated protozoa.  Rico, D., Martín-González, A., Díaz, S., de Lucas, P., & Gutiérrez, J.C. Comp. Biochem. Physiol. Part C.  149, 90-96. 2009.
  •  Two new members of the Tetrahymena multi-stress.inducible metallothionein family: Characterization and expression analysis of T. rostrata Cd/Cu metallothionein genes.  Amaro, F., de Lucas, MP., Martín-González, A. & Gutiérrez, J.C.  Gene.  423, 85-91. 2008.
  • Ciliates as cellular tools to study the eukaryotic cell-heavy metal interactions.  Gutiérrez, J.C., Martín-González, A., Díaz, S., Amaro, F., Ortega, R., Gallego, A. & de Lucas, M.P. En: Heavy Metal Pollution.  S.E. Brown & W.C. Welton (Eds.).  Nova Publishers. (EEUU). ISBN: 978-1-60456-899-8. 2008.
  • Tetrahymena  metallothioneins fall into two discrete subfamilies.  Díaz, S., Amaro, F., Rico, D., Campos, V., Benítez, L., Martín-González, A., Hamilton, E.P., Orias, E. & Gutiérrez, J.C. PloSONE.  2(3): e291. doi:10.1371/journal.pone.0000291. 2007.
  • Flow cytometry assessment of cytotoxicity and reactive oxygen species generation by single and binary mixtures of cadmium, zinc and copper on populations of the ciliated protozoan Tetrahymena thermophila. Gallego, A., Martín-González, A., Ortega, R. & Gutiérrez, J.C. Chemosphere. 68, 647-661. 2007.
  • Evaluation of heavy metal acute toxicity and bioaccumulation in soil ciliated protozoa.  Martín-González, A., Díaz, S. & Gutiérrez, J.C. Environment International . 32, 711-717. 2006.
  • Cytotoxicity and Bioaccumulation of heavy metals by ciliated protozoa isolated from urban wastewater treatment plants. Martín-González, A., Borniquel, S., Díaz, S., Gallego, A. & Gutiérrez,J.C. Research in Microbiology. 157, 108 -118. 2006.
  • Isolation and characterization of a cDNA encoding a putative high mobility group (HMG)-box protein from stored mRNA in resting cysts of the ciliate Oxytricha (Sterkiella) nova. Callejas,S. & Gutiérrez,J.C.  Molecular Biology Reports. 30, 215-222. 2003.
  • A simple and rapid PCR -based method to isolate complete small macronuclear minichromosomes from hypotrich ciliates: 5S rDNA and S26 ribosomal protein gene of Oxytricha (Sterkiella) nova. Callejas S. & Gutiérrez, J.C. Protist. 153, 133- 142. 2002.
  • DNA methylation in ciliates: implications in differentiation processes. Gutiérrez,J.C., Callejas,S., Borniquel,S. & Martin-González,A. International Microbiology. 3, 139-146. 2000. 
  • Functional GFP-metallothionein fusion protein from Tetrahymena thermophila: a potential whole-cell biosensor for monitoring heavy metal pollution and a cell model tu study metallothionein overproduction effects. Amaro F., Turkewitz A., Martin-Gonzalez A. & Gutierrez JC. BioMetals.27, 195-205. 2014. 




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