Damien O'Halloran

Damien O'Halloran
Associate Professor of Biology
Bell Hall 307
[email protected]
O'Halloran Lab

Current Research

Circuit neurobiology

My lab broadly studies how neural circuits are built during development and function in adulthood; we use the model organism Caenorhabditis elegans to answer these questions. In terms of circuit function, our research has covered gustatory and thermosensory circuits in C. elegans but our main focus examines olfaction. Previous work identified a protein kinase G (PKG) called EGL-4 that is necessary for short and long-term olfactory adaptation in C. elegans. It has been shown that transient nuclear localization of EGL-4 in the AWC neuron facilitates adaptation after sustained odor input, and my lab has demonstrated that constitutively nuclear EGL-4 is required in the AWB neurons (another pair of olfactory neurons) for the detection of repellent odors. Our research also revealed that the cyclic nucleotide gated (CNG) channel subunit CNG-3 is necessary for short-term adaptation in the AWC neurons, and a separate CNG channel subunit called CNG-1 is required to promote cross adaptation responses between distinct olfactory cues. In terms of circuit development, my lab began examining the family of sodium calcium exchangers (NCX). We chose this family based on extensive literature implicating calcium in circuit development. From our research into NCX, we have found a link between calcium homeostasis via NCX and circuit patterning within a subset of motor neurons in C. elegans.

Parasitic Nematodes

My lab also studies the neurobiology of nematode parasitism. We are attempting to understand the host factors which are sensed by parasitic nematodes that initiate the infection process. The insect parasite Heterorhabditis bacteriophora offers great potential as a model of nematode parasitism; with its endosymbiotic bacteria - Photorhabdus luminescens - H. bacteriophora invades multiple insect species (including Drosophila melanogaster), which it kills and exploits as a food source for the development of several nematode generations. When the insect cadaver is exhausted, infective (dauer) juveniles (IJs) exit and seek a new host to infect. We are using the Drosophila-Heterorhabditis system to study the infection process. My lab is also interested in the neurobiology of anthelminthic drug activity, and have identified strains of anthelminthic resistant hookworm which we are studying to understand anthelminthic resistance.


Kenney E, Hawdon JM, O'Halloran D, Eleftherianos I. Heterorhabditis
bacteriophora Excreted-Secreted Products Enable Infection by Photorhabdus
luminescens Through Suppression of the Imd Pathway. Front Immunol. 2019 Oct
4;10:2372. doi: 10.3389/fimmu.2019.02372. eCollection 2019. PubMed PMID:
31636642; PubMed Central PMCID: PMC6787769.

Aldras Y, Singh S, Bode K, Bhowmick DC, Jeremic A, O'Halloran DM. An inducible
model of human amylin overexpression reveals diverse transcriptional changes.
Neurosci Lett. 2019 Jun 21;704:212-219. doi: 10.1016/j.neulet.2019.04.016. Epub
2019 Apr 8. PubMed PMID: 30974231; PubMed Central PMCID: PMC6594890.

Kitchen S, Ratnappan R, Han S, Leasure C, Grill E, Iqbal Z, Granger O,
O'Halloran DM, Hawdon JM. Isolation and characterization of a naturally occurring
multidrug-resistant strain of the canine hookworm, Ancylostoma caninum. Int J
Parasitol. 2019 Apr;49(5):397-406. doi: 10.1016/j.ijpara.2018.12.004. Epub 2019
Feb 14. PubMed PMID: 30771359; PubMed Central PMCID: PMC6456372.

O'Halloran DM. Genome aware CRISPR gRNA target prediction for parasitic
nematodes. Mol Biochem Parasitol. 2019 Jan;227:25-28. doi:
10.1016/j.molbiopara.2018.12.001. Epub 2018 Dec 7. PubMed PMID: 30529475.

Bode K, O'Halloran DM. NCX-DB: a unified resource for integrative analysis of
the sodium calcium exchanger super-family. BMC Neurosci. 2018 Apr 13;19(1):19.
doi: 10.1186/s12868-018-0423-2. PubMed PMID: 29649983; PubMed Central PMCID:

Vadnal J, Granger OG, Ratnappan R, Eleftherianos I, O'Halloran DM, Hawdon JM.
Refined ab initio gene predictions of Heterorhabditis bacteriophora using
RNA-seq. Int J Parasitol. 2018 Jul;48(8):585-590. doi:
10.1016/j.ijpara.2018.02.001. Epub 2018 Mar 9. PubMed PMID: 29530648; PubMed
Central PMCID: PMC6004328.

O'Halloran DM. fastQ_brew: module for analysis, preprocessing, and
reformatting of FASTQ sequence data. BMC Res Notes. 2017 Jul 12;10(1):275. doi:
10.1186/s13104-017-2616-7. PubMed PMID: 28701181; PubMed Central PMCID:

O'Halloran DM. phylo-node: A molecular phylogenetic toolkit using Node.js.
PLoS One. 2017 Apr 14;12(4):e0175480. doi: 10.1371/journal.pone.0175480.
eCollection 2017. PubMed PMID: 28410421; PubMed Central PMCID: PMC5391935.

O'Halloran DM, Uriagereka-Herburger I, Bode K. STITCHER 2.0: primer design for
overlapping PCR applications. Sci Rep. 2017 Mar 30;7:45349. doi:
10.1038/srep45349. PubMed PMID: 28358011; PubMed Central PMCID: PMC5371788.

O'Halloran DM, Altshuler-Keylin S, Zhang XD, He C, Morales-Phan C, Yu Y, Kaye
JA, Brueggemann C, Chen TY, L'Etoile ND. Contribution of the cyclic nucleotide
gated channel subunit, CNG-3, to olfactory plasticity in Caenorhabditis elegans.
Sci Rep. 2017 Mar 13;7(1):169. doi: 10.1038/s41598-017-00126-7. PubMed PMID:
28279024; PubMed Central PMCID: PMC5427828.

Sharma V, Roy S, Sekler I, O'Halloran DM. The NCLX-type Na(+)/Ca(2+)
Exchanger NCX-9 Is Required for Patterning of Neural Circuits in Caenorhabditis
elegans. J Biol Chem. 2017 Mar 31;292(13):5364-5377. doi:
10.1074/jbc.M116.758953. Epub 2017 Feb 14. PubMed PMID: 28196860; PubMed Central
PMCID: PMC5392681.

Vadnal J, Ratnappan R, Keaney M, Kenney E, Eleftherianos I, O'Halloran D,
Hawdon JM. Identification of candidate infection genes from the model
entomopathogenic nematode Heterorhabditis bacteriophora. BMC Genomics. 2017 Jan
3;18(1):8. doi: 10.1186/s12864-016-3468-6. PubMed PMID: 28049427; PubMed Central
PMCID: PMC5209865.

O'Halloran DM. A Guide to Using STITCHER for Overlapping Assembly PCR
Applications. Methods Mol Biol. 2017;1472:3-11. doi: 10.1007/978-1-4939-6343-0_1.
PubMed PMID: 27671928.

He C, Altshuler-Keylin S, Daniel D, L'Etoile ND, O'Halloran D. The cyclic
nucleotide gated channel subunit CNG-1 instructs behavioral outputs in
Caenorhabditis elegans by coincidence detection of nutritional status and
olfactory input. Neurosci Lett. 2016 Oct 6;632:71-8. doi:
10.1016/j.neulet.2016.08.037. Epub 2016 Aug 22. PubMed PMID: 27561605.

O'Halloran DM. NemaCount: quantification of nematode chemotaxis behavior in a
browser. Invert Neurosci. 2016 Jun;16(2):5. doi: 10.1007/s10158-016-0188-1. Epub
2016 May 21. PubMed PMID: 27209025.

Ratnappan R, Vadnal J, Keaney M, Eleftherianos I, O'Halloran D, Hawdon JM.
RNAi-mediated gene knockdown by microinjection in the model entomopathogenic
nematode Heterorhabditis bacteriophora. Parasit Vectors. 2016 Mar 18;9:160. doi:
10.1186/s13071-016-1442-4. PubMed PMID: 26993791; PubMed Central PMCID:

O'Halloran DM. PrimerMapper: high throughput primer design and graphical
assembly for PCR and SNP detection. Sci Rep. 2016 Feb 8;6:20631. doi:
10.1038/srep20631. PubMed PMID: 26853558; PubMed Central PMCID: PMC4745053.

Sharma V, O'Halloran DM. Nematode Sodium Calcium Exchangers: A Surprising
Lack of Transport. Bioinform Biol Insights. 2016 Feb 1;10:1-4. doi:
10.4137/BBI.S37130. eCollection 2016. PubMed PMID: 26848260; PubMed Central
PMCID: PMC4737524.

O'Halloran DM. PrimerView: high-throughput primer design and visualization.
Source Code Biol Med. 2015 Jun 4;10:8. doi: 10.1186/s13029-015-0038-2.
eCollection 2015. PubMed PMID: 26052342; PubMed Central PMCID: PMC4456780.

He C, O'Halloran DM. Analysis of the Na+/Ca2+ exchanger gene family within
the phylum Nematoda. PLoS One. 2014 Nov 14;9(11):e112841. doi:
10.1371/journal.pone.0112841. eCollection 2014. PubMed PMID: 25397810; PubMed
Central PMCID: PMC4232491.

O'Halloran D. A practical guide to phylogenetics for nonexperts. J Vis Exp.
2014 Feb 5;(84):e50975. doi: 10.3791/50975. PubMed PMID: 24562012; PubMed Central
PMCID: PMC4116784.

Sharma V, O'Halloran DM. Recent structural and functional insights into the
family of sodium calcium exchangers. Genesis. 2014 Feb;52(2):93-109. doi:
10.1002/dvg.22735. Epub 2013 Dec 27. Review. PubMed PMID: 24376088.

O'Halloran DM. STITCHER: A web resource for high-throughput design of primers
for overlapping PCR applications. Biotechniques. 2015 Jun 1;58(6):325-8. doi:
10.2144/000114301. eCollection 2015 Jun. PubMed PMID: 26054769.

Wang D, O'Halloran D, Goodman MB. GCY-8, PDE-2, and NCS-1 are critical
elements of the cGMP-dependent thermotransduction cascade in the AFD neurons
responsible for C. elegans thermotaxis. J Gen Physiol. 2013 Oct;142(4):437-49.
doi: 10.1085/jgp.201310959. PubMed PMID: 24081984; PubMed Central PMCID:

He C, Fitzpatrick DA, O'Halloran DM. A comparative study of the molecular
evolution of signalling pathway members across olfactory, gustatory and
photosensory modalities. J Genet. 2013;92(2):327-34. PubMed PMID: 23970093.

He C, O'Halloran DM. Nuclear PKG localization is regulated by G₀ alpha and is
necessary in the AWB neurons to mediate avoidance in Caenorhabditis elegans.
Neurosci Lett. 2013 Oct 11;553:35-9. doi: 10.1016/j.neulet.2013.08.011. Epub 2013
Aug 14. PubMed PMID: 23954825.

Sharma V, He C, Sacca-Schaeffer J, Brzozowski E, Martin-Herranz DE,
Mendelowitz Z, Fitzpatrick DA, O'Halloran DM. Insight into the family of Na+/Ca2+
exchangers of Caenorhabditis elegans. Genetics. 2013 Oct;195(2):611-9. doi:
10.1534/genetics.113.153106. Epub 2013 Jul 26. PubMed PMID: 23893482; PubMed
Central PMCID: PMC3781985.

Wojtyniak M, Brear AG, O'Halloran DM, Sengupta P. Cell- and subunit-specific
mechanisms of CNG channel ciliary trafficking and localization in C. elegans. J
Cell Sci. 2013 Oct 1;126(Pt 19):4381-95. doi: 10.1242/jcs.127274. Epub 2013 Jul
25. PubMed PMID: 23886944; PubMed Central PMCID: PMC3784820.

Smith HK, Luo L, O'Halloran D, Guo D, Huang XY, Samuel AD, Hobert O. Defining
specificity determinants of cGMP mediated gustatory sensory transduction in
Caenorhabditis elegans. Genetics. 2013 Aug;194(4):885-901. doi:
10.1534/genetics.113.152660. Epub 2013 May 20. PubMed PMID: 23695300; PubMed
Central PMCID: PMC3730918.

He C, Lee JI, L'Etoile N, O'Halloran D. A molecular readout of long-term
olfactory adaptation in C. elegans. J Vis Exp. 2012 Dec 22;(70). pii: 4443. doi:
10.3791/4443. PubMed PMID: 23287821; PubMed Central PMCID: PMC3576423.

Fitzpatrick DA, O'Halloran DM. Investigating the Relationship between
Topology and Evolution in a Dynamic Nematode Odor Genetic Network. Int J Evol
Biol. 2012;2012:548081. doi: 10.1155/2012/548081. Epub 2012 Sep 28. PubMed PMID:
23056995; PubMed Central PMCID: PMC3465961.

O'Halloran DM, Hamilton OS, Lee JI, Gallegos M, L'Etoile ND. Changes in cGMP
levels affect the localization of EGL-4 in AWC in Caenorhabditis elegans. PLoS
One. 2012;7(2):e31614. doi: 10.1371/journal.pone.0031614. Epub 2012 Feb 3. PubMed
PMID: 22319638; PubMed Central PMCID: PMC3272044.

Lee JI, O'Halloran DM, Eastham-Anderson J, Juang BT, Kaye JA, Scott Hamilton
O, Lesch B, Goga A, L'Etoile ND. Nuclear entry of a cGMP-dependent kinase
converts transient into long-lasting olfactory adaptation. Proc Natl Acad Sci U S
A. 2010 Mar 30;107(13):6016-21. doi: 10.1073/pnas.1000866107. Epub 2010 Mar 10.
PubMed PMID: 20220099; PubMed Central PMCID: PMC2851914.

O'Halloran DM, Altshuler-Keylin S, Lee JI, L'Etoile ND. Regulators of
AWC-mediated olfactory plasticity in Caenorhabditis elegans. PLoS Genet. 2009
Dec;5(12):e1000761. doi: 10.1371/journal.pgen.1000761. Epub 2009 Dec 11. PubMed
PMID: 20011101; PubMed Central PMCID: PMC2780698.

O'Halloran DM, Fitzpatrick DA, McCormack GP, McInerney JO, Burnell AM. The
molecular phylogeny of a nematode-specific clade of heterotrimeric G-protein
alpha-subunit genes. J Mol Evol. 2006 Jul;63(1):87-94. Epub 2006 Jun 16. PubMed
PMID: 16786439.

Fitzpatrick DA, O'Halloran DM, Burnell AM. Multiple lineage specific
expansions within the guanylyl cyclase gene family. BMC Evol Biol. 2006 Mar
20;6:26. PubMed PMID: 16549024; PubMed Central PMCID: PMC1435932.

O'Halloran DM, Cafferkey MT. Multiplex PCR for identification of seven
Streptococcus pneumoniae serotypes targeted by a 7-valent conjugate vaccine. J
Clin Microbiol. 2005 Jul;43(7):3487-90. PubMed PMID: 16000486; PubMed Central
PMCID: PMC1169178.

O'Halloran DM, Burnell AM. An investigation of chemotaxis in the insect
parasitic nematode Heterorhabditis bacteriophora. Parasitology. 2003 Oct;127(Pt
4):375-85. PubMed PMID: 14636024.

Classes Taught

BISC 2220 - Developmental Neurobiology

BISC 2320 - Neural Circuits and Behavior

BISC 4180 - Undergraduate Research Seminar