Unicellular Ciliate Tetrahyema Thermophila

Unicellular Ciliate Tetrahyema Thermophila



The module focuses on papers that all use a single model organism, the unicellular ciliate Tetrahyema thermophila.


The module consists of a short popular press article to introduce the organism, followed by three articles from the research literature that collectively cover a large range of content: lipid structure, membrane structure and fluidity, enzyme function, protein structure and conservation, adaptation to the environment, transcription and translation, nucleic acids and hybridization, gene regulation, ciliary structure and function, signaling pathways, genetics and sex determination mechanisms. There is an added potential advantage of being able to coordinate inexpensive laboratory activities with this organism

Applicable for Courses:

Introductory Biology (Majors)

Educational Level:


Roadmap Objectives:

    • Article: Nakashima, S., Zhao, Y., Nozawa, Y. (1996). Molecular cloning of Δ9 fatty acid desaturase from the protozoan Tetrahyema thermophila and its mRNA expression during thermal membrane adaptation. Biochem. J. 317: 29-34
    • Content area/major concepts: Previous work had shown that a decrease in environmental temperature caused an increase in the amount of unsaturated fatty acids in the membrane of Tetrahyema thermophila, which in turn helped to maintain membrane fluidity. The authors of this paper demonstrated that one of the enzymes responsible for converting saturated fatty acids to unsaturated fatty acids is upregulated with a decrease in temperature and that the mRNA for this enzyme also becomes more stable (Figs. 5, 6 and 8). To do this they also had to clone the T. thermophila enzyme in order to generate probes for Northern blot expression. From the cloned sequence they also derived an amino acid sequence, examined the homology and conservation of the protein to other species, and derived hydrpathy plots to look for membrane topology.

      fatty acid structure, carbon bond saturation, membrane structure, fluidity, thermal adaptation, PCR, nucleic acid structure and hybridization, mRNA, transcription and translation, gene expression and regulation, enzyme function.
    • Methods or technology used to obtain data: T. thermophila culture, PCR, cDNA library screening, Northern blotting, mRNA stability assay, amino acid sequence comparison, hydropathy plots.
    • How the CREATE strategy was used: To be determined.
    • Biggest teaching challenge: This paper covers many of the first semester topics of the course, but some of the more difficult ones (gene regulation) would come up well before they would normally get covered in class. I would probably focus on Figs 5 and 6 and stay on the topics of membrane lipids and enzyme function.
    • Article: Bartholomew, J., Reichart, J., Mundy, R., Recktenwald, J., Keyser, S., Riddle, M., Kuruvilla, H. (2008). GTP avoidance in Tetrahyema thermophila requires tyrosine kinase activity, intracellular calcium, NOS, and guanylyl cyclase. Purinergic Signalling 4: 171-181.
    • Content area/major concepts: Previous work had shown that T. thermophila will avoid micromolar concentrations of extracellular GTP, by reversing the direction of beating of the cilia. This can be observed behaviorally as chaotic swimming activity. The authors of this study wanted to examine the signal pathways activated when GTP causes this response.

      nucleotides, receptors, ciliary structure and function, signaling pathways with calcium, nitric oxide, inhibitors and calcium chelators.
    • Methods or technology used to obtain data: Behavior (swimming) asays, microscopy, western blot, immunofluorescence, enzyme immunosorbant assay, chemical assays.
    • How the CREATE strategy was used: To be determined.
    • Biggest teaching challenge:
    • Article: Cervantes, M.D., Hamilton, E.P., Xiong, J., Lawson, M.J., Yuan, D., Hadjithomas, M., Miao, W., Orias, E. (2013). Selecting one of several mating types through gene segment joining and deletion in Tetrahyema thermophila. PLOS Biology 11: e1001518, 1-15.
    • Content area/major concepts:
    • Methods or technology used to obtain data:
    • How the CREATE strategy was used:
    • Biggest teaching challenge:

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