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Todd M. Hennessey
Membrane Biochemistry and Cell
Physiology
Professor
PhD 1981 University of
Wisconsin-Madison
Postdoctoral work 1981 University of Wisconsin-Madison
Assistant Professor 1985;
Associate Professor 1991 University at Buffalo
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Address Information
Todd M. Hennessey
Department of Biological Sciences
610 Hochstetter Hall
State University of New York at Buffalo
Buffalo, NY 14260
(716) 645-4973
To send e-mail: thennes@buffalo.edu
RESEARCH SUMMARY
We are using the
unicellular eukaryotes Paramecium and Tetrahymena
as model sensory cells to study the chemosensory pathways
involved in cellular responses to depolarizing chemorepellents
such as ATP, GTP, and polycations (such as lysozyme) as well as
the mechanisms responsible for adaptation to these stimuli.
Swimming behaviors are used in convenient bioassays to estimate
the responsiveness of these free swimming sensory cells and
intracellular electrophysiology is done to confirm the roles of
specific ionic conductances. These unicellular eukaryotic cells
can be grown to high densities in clonal, axenic cultures so that
large amounts of cells can be obtained as starting material for
biochemical and molecular analyses. "Genetic
dissection" of the sensory transduction and adaptation
pathways can be approached by screening for behavioral mutants
that have altered responses to chemoeffectors. Molecular
Biological approaches such as gene knockouts, RNAi and antisense
ribosome mutagenesis are used to study the regulation and
functional expression of the gene products involved in
chemosensory transduction and adaptation in Tetrahymena.
We have also begun a collaboration with Dr David Pennock at Miami
University in Ohio to generate and characterize knockout mutants
of the various inner arm dynein heavy chain genes of Tetrahymena
to help to understand the roles of the different ciliary dyneins
in proper ciliary function.
SELECTED PROJECTS
Purification, cloning and regulated expression of
and ectonucleotidases in Tetrahymena
T. Smith, T. Santangelo, T. Hennessey
Tetrahymena hydrolyze external nucleotide triphosphates
(like ATP and GTP) by an ecto-nTPase and external
nucleotide monophosphates (like AMP and GMP) by a
different ecto-nMPase. The ecto-nTPase may be involved in
inactivating external GTP as a signaling molecule because
GTP is a chemorepellent (Clark et al., 1993). This may be
analogous to a system such as
acetylcholine/acetylcholinesterase. The ecto-nTPase may
also act as either a cell adhesion molecule in the mating
response or in extracellular metabolism of nucleotide
phosphates to provide for their guanine auxotrophy. The
ecto-nMPase may also be involved in this extracellular
scavenge pathway for nucleotides. These two enzymes
(ecto-nTPase and ecto-nMPase) will be characterized in
vivo and in vitro, purified, sequenced, and cloned to
provide the molecular tools necessary to study their
functions and possible regulation of functional surface
expression. Monoclonal antibodies are also being
generated to aid in these efforts.
PUBLICATIONS
- Liu,S., Hennessey,T., Rankin,S. and Pennock,D.G. (2005) Mutations
in genes encoding inner arm dynein heavy chains in
Tetrahymena thermophila lead to axonemal hypersensitivity
to Ca++. Cell Motil. & Cytoskel.
62(3):133-40.
- Hennessey,T.M. (2005). Responses of the ciliates
Tetrahymena and Paramecium to external ATP and GTP. Purinergic
Signaling 1: 101-110.
- Snyder RJ, Hennessey TM (2004) Cold tolerance and
homeoviscous adaptation in freshwater alewives (Alosa
pseudoharengus). Fish Physiol. Biochem.
29 (2): 117-126
- Liu,S., Hard,R., Rankin,S., Hennessey,T. and Pennock,D.
(2004). Disruption of genes encoding inner arm dynein
heavy chains causes motility phenotypes in Tetrahymena.
Cell Motil. & Cytoskel. 59:201-214.
- Wood,C.R. and Hennessey,T.M. (2003). PPNDS is an
agonist, not an antagonist, for the ATP receptor of
Paramecium. J. Exp. Biol.
206:627-636.
- Hennessey, T.M., Kim,D.Y., Oberski,D.J., Hard,R.,
Rankin,S.A., Pennock.D.G. (2002). Inner arm dynein 1
is essential for Ca++-dependent ciliary reversals in
Tetrahymena thermophila. Cell Motil. And
Cytoskel. 53(4): 281-288.
- Hennessey,T.M. and Kuruvilla,H.G. (2000).
Electrophysiology of Tetrahymena.
In: Methods in Cell Biology. (D.J.
Asai and J.D. Forney, Eds.), vol. 62, pp.363-377.
- Kuruvilla,H.G. and Hennessey,T.M. (1999).
Chemosensory responses of Tetrahymena thermophila to
CB2, a 24 amino acid fragment of lysozyme.
J. Comp. Physiol. 184:529-534.
- Kim,M.Y., Kuruvilla,H.G., Ragu,S. and Hennessey,T.M.
(1999).
ATP reception and chemosensory adaptation in
Tetrahymena thermophila.
J. Exp. Biol. 202(4):407-416.
- Kuruvilla,H.G. and Hennessey,T.M. (1998).
Purification and characterization of a novel lysozyme
chemoreceptor from Tetrahymena thermophila.
J. Membr. Biol. 162:51-57.
- H.G. Kuruvilla, M.Y. Kim, and T.M. Hennessey (1997)
Chemosensory adaptation to lysozyme and GTP involves
independently regulated receptors in Tetrahymena
thermophilla.
J. Eukaryotic Microbiol. 44:(3): 263-268
- T.M. Smith, T.L. Kirley, and T.M. Hennessey (1997)
A soluble ecto-ATPase from Tetrahymena thermophilla:
Purification and similarity to the membrane-bound
ecto-ATPase of smooth muscle.
Arch. Biochem. Biophys. 337: 351-359
- Francis, J.T. and Hennessey, T.M. (1995)
Chemorepellents in Paramecium and Tetrahymena
J. Euk. Microbiol 41:244-262
- T.M. Hennessey, (1990)
Ion current of Paramecium: Effects of mutations and
drugs.
In: Evolution of the First
Nervous Systems (Ed. Peter A.V. Anderson)
pp. 215-235. Plenum Press, New York
- R.D. Hinrichsen, T. Burgess-Cassler, B.Soltvedt, T.M.
Hennessey, and C. Kung (1986)
Calmodulin restores a missing Ca++ dependent
K+ current in mutants of Paramecium
Science 232:503-506
Surface membrane preparation (pellicle) from
Paramecium.