Photo: Caden Churchill

Abbott, C., Bright, D., Bryant, H., Côté, G., Crookes, S., Gurney, K., Hanner, R., Helbing, C., Hocking, M., Khan, I., Langlois, V.S., Lemay, M., Marshall, N., Miliano, R., Mirabzadeh-Ardakani, A., Parent, G., Richter, C., Wagener, A., Wilson, C., and Clogg-Wright, K. 2023. Performance criteria for the analyses of environmental DNA by targeted quantitative polymerase chain reaction. National standard of Canada, CSA W219:23. Canadian Standards Association, Toronto, Ontario, Canada. 29 pp.

Lopez, M.L., Bonderud, M., Allison, M.J., MacDermid, F., Ussery, E., McMaster, M.E., Dersch, A., Staniszewska, K.J., Drevnick, P., Cooke, C.A., and Helbing, C.C. 2023. qPCR-based eDNA workflow for humic-rich lake sediments: Combined use of sedimentary DNA (sedDNA) and Indigenous knowledge in reconstructing historical fish records. Ecological Indicators, 155, 111014.

Allison, M.J., Warren, R., Lopez, M.L., Acharya-Patel, N., Imbery, J.J., Coombe, L., Yang, C.L., Birol, I., and Helbing, C.C. 2023. Enabling robust environmental DNA assay design with unikseq for the identification of unique target taxon-specific regions within whole mitochondrial genomes. eDNA Journal, 5: 1032. DOI: 10.1002/edn3.438.

Sawitsky, J., Kwok, H., Filewood, T., McCallum, P., Brunswick, P., Yan, J., Kim, M., Helbing, C.C., and Shang, D. 2023. Method development for quantitative analysis of polycyclic aromatic hydrocarbons, nitrogen heterocycles and sulfur heterocycles in crude oils using quadropole time-of-flight mass spectrometry. Environmental Forensics, accepted.

Huston, G., Lopez, M.L., Helbing, C.C., Kinnison, M., Saros, J., Cheng, Y., King, L., Duxbury, L., Gregory-Eaves, I., Monchamp, M.E., Wood, S.A., Thomson-Laing, G., Picard, M., Armbrecht, L., Doi, H., Ficetola, G.F., Myler, E., Hanner, R., Kurte, L., Von Eggers, J., Brahney, J., Sakata, M.K., Kuwae, M., Parent, G., and Capo, E. 2023. Detection of fish sedimentary DNA (sedDNA) in aquatic systems: A review of methodological uncertainties and future opportunities. eDNA Journal, accepted. DOI: 10.1002/edn3.467

Beattie, R.E., Helbing, C.C., Imbery, J.J., Klymus, K.E., Lopez Duran, J., Richter, C.A., Thambirajah, A.A., Thompson, N., and Edwards, T.M. 2023. A nitrifier-enriched microbial community contributes to the degradation of environmental DNA. eDNA Journal, accepted. DOI: 10.1002/edn3.469.

Thambirajah, A.A., Miliano, R.C., Abbott, E.A., Buday, C., Shang, D., Kwok, H., and Helbing, C.C. 2023. Dynamic cyp1a1 transcript responses in the caudal fin of coho salmon (Oncorhynchus kisutch) smolts to low sulfur marine diesel water accommodated fraction exposures and depuration. Aquatic Toxicology, 256: 106412. DOI: 10.1016/j.aquatox.2023.106412.

Poulsen, R., Jackman, S.H., Hansen, M., and Helbing, C.C. 2023. Relationship between serum thyroid hormones and their associated metabolites, and gene expression bioindicators in the back skin of Rana [Lithobates] catesbeiana tadpoles and frogs during metamorphosis. Frontiers in Endocrinology, 13: 1103051. DOI: 10.3389/fendo.2022.1103051.

Acharya-Patel, N., Allison, M.J., and Helbing, C.C. 2023. Chapter 5. Environmental DNA: Revolutionizing ecological assessments with genomics, pp 103-124 in: Genomics and the global bioeconomy (C. Lopez-Correa and A. Suarez-Gonzalez, eds), Translational and applied genomics series (G. Patrinos, series ed), Elsevier Inc., Cambridge, MA. 341 pp. ISBN 978-0-323-91601-1. Invited chapter.


Richter, A., Sutherland, D., Ebrahimikondori, H., Babcock, A., Louie, N., Li, C., Coombe, L., Lin, D., Warren, R.L., Yanai, A., Helbing, C.C., Hof, F., Hoang, L.M.N., and Birol, I. 2022. Associating biological activity and predicted structure of antimicrobial peptides from amphibians and insects. 2022. Antibiotics, 11: 1710. DOI: 10.3390/antibiotics11121710. **Feature Paper that represents the most advanced research with significant potential for high impact in the field.

Koide, E.M., Abbott, E.A., and Helbing, C.C. 2022. Uncovering early thyroid hormone signalling events through temperature-mediated activation of molecular memory in the cultured bullfrog tadpole tail fin. General and Comparative Endocrinology, 323-324: 114047. DOI: 10.1016/j.ygcen.2022.114047.

Jackman, S.H.*, Evans, E.P.*, Kuecks-Winger, H., Corrie, L.M., Imbery, J.J., Miliano, R.C., Roberts, B.J., Thompson, V.C., Thambirajah, A.A., Lesperance, M.L., Pyle, G.G., van Aggelen, G., and Helbing, C.C. 2022. Comparison of transcriptome responses of the liver, tailfin, and olfactory epithelium of Rana [Lithobates] catesbeiana tadpoles disrupted by thyroid hormones and estrogen. Aquatic Toxicology, 253: 106344. DOI: 10.1016/j.aquatox.2022.106344.

Jia, B., Garlock, E., Lo, R., Allison, M.J., Round, J.R., Helbing, C.C., Verreault, J., and Brinkman, F.S.L. 2022. Characterizing the relationship between the skin microbiome and flame retardant exposure of the endangered St. Lawrence estuary beluga. Frontiers in Environmental Science, 10: 954060. DOI: 10.3389/fenvs.2022.954060.

Hocking, M.D.*, MacAdams, J.*, Sneiderman, R.B., Allison, M.J, Bergman, L.C., Koop, B., Starzomski, B., Lesperance, M.L., and Helbing, C.C. 2022. Establishing the signal above the noise in field applications: Accounting for an environmental background in the detection and quantitation of salmonid eDNA. Fishes, 7: 266. DOI: 10.3390/fishes7050266.

Robinson, C.L.K., Bergman, L.C., Allison, M.J., Huard, J., Sutherst, J., and Helbing, C.C. 2022. The utility of environmental DNA to detect intertidal habitat use by forage fish. Ecological Indicators, 142:109306. DOI:10.1016/j.ecolind.2022.109306.

Lin, D., Sutherland, D., Aninta, S.I., Louie, N., Nip, K.M., Li, C., Yanai, A., Coombe, L., Warren, R.L., Helbing, C.C., Hoang, L.M.N., and Birol, I. 2022. Mining amphibian and insect transcriptomes for antimicrobial peptide sequences with rAMPage. Antibiotics, 11:952. DOI: 10.3390/antibiotics11070952.

Filewood, T., Kwok, H., Brunswick, P., Yan, J., Ollinik, J.E., Cote, C., Kim, M., van Aggelen, G., Helbing, C.C. and Shang, D. 2022. A rapid gas chromatography time-of-flight mass spectrometry method for the determination of polycyclic aromatic sulfur heterocycles for application in spilled crude oils. Analytical Methods, 14: 717-725. DOI: 10.1039/d1ay02216d.

Filewood, T., Kwok, H., Brunswick, P., Yan, J., Ollinik, J.E., Cote, C., Kim, M., van Aggelen, G., Helbing, C.C. and Shang, D. 2022. Investigating the fate of polycyclic aromatic sulfur heterocycle compounds in spilled oils with a microcosm weathering experiment. Environmental Systems Research, 11:6. DOI: 10.1186/s40068-022-00252-w.

Filewood, T., Kwok, H., Brunswick, P., Yan, J., Ollinik, J.E., Cote, C., Kim, M., van Aggelen, G., Helbing, C.C. and Shang, D. 2022. Advancement in oil forensics through the addition of polycyclic aromatic sulfur heterocycles as biomarkers in diagnostic ratios. Journal of Hazardous Materials, 435:129027. DOI: 10.1016/j.jhazmat.2022.129027.

Li, C., Sutherland, D., Hammond, S.A., Yang, C., Taho, F., Bergman, L., Houston, S., Warren, R.L., Wong, T., Hoang, L.N.M., Cameron, C.E., Helbing, C.C., and Birol, I. 2022. AMPlify: attentive deep learning model for discovery of novel antimicrobial peptides effective against WHO priority pathogens. BMC Genomics, 23:77. DOI: 10.1186/s12864-022-08310-4.

Thambirajah, A.A., Wade, M.G., Verreault, J., Buisine, N., Alves, V.A., Langlois, V.S., Helbing, C.C., 2022. Disruption by stealth – Interference of Endocrine-Disrupting Chemicals on hormonal crosstalk with thyroid axis function in humans and other animals. Environmental Research, 203: 111906. DOI: 10.1016/j.envres.2021.111906.


Langlois, V.S., Helbing, C.C., Dupras, J., and Bernatchez, L. 2021. Utiliser l’ADN pour suivre avec précision la trace des animaux dans leur milieu naturel. The Conversation. ​

Matthias, L., Allison, M.J., Maslovat, C.Y., Hobbs, J., and Helbing, C.C. 2021. Improving ecological surveys for the detection of cryptic, fossorial snakes using eDNA on and under artificial cover objects. Ecological Indicators, 131: 108187. DOI: 10.1016/j.ecolind.2021.108187

Gagné, N., Bernatchez, L., Bright, D., Côté, G., Coulson, M., Gurney, K., Hanner, R., Helbing, C., Hobbs, J., Hocking, M., Khan, I., Naumann, C., Parent, G., Richter, C., Silverio, C., Skinner, M., Weir, A., Wilcox, T., Wilson, C., and Clogg-Wright, K. 2021. Environmental DNA (eDNA) reporting requirements and terminology. National standard of Canada, CSA W214:21. Canadian Standards Association, Toronto, Ontario, Canada. 31 pp.

Langlois, V.S., Allison, M.J., Bergman, L.C., To, T.A., and Helbing, C.C. 2021. The need for robust qPCR-based eDNA detection assays in environmental monitoring and risk assessments. Environmental DNA, 3: 519-527. DOI: 10.1002/edn3.164.

Lesperance, M., Allison, M.J., Bergman, L.C., Hocking, M.D., and Helbing, C.C. 2021. A statistical model for calibration and computation of detection and quantification limits for low copy number environmental DNA samples. Environmental DNA, 3: 970-981. DOI: 10.1002/edn3.220
(eLowQuant R code available here:

Corrie, L.M., Kempe, M.N., Blajkevitch, O., Shang, D., and Helbing, C.C. 2021. Dioctyl sodium sulfosuccinate as a potential endocrine disruptor of thyroid hormone activity in American bullfrog, Rana (Lithobates) catesbeiana, tadpoles. Archives of Environmental Contamination and Toxicology, 80: 726-734. DOI: 10.1007/s00244-021-00835-1

Abbott, E.A. and Helbing, C.C. 2021. Investigation of sucralose as a disruptor of thyroid hormone activity in American bullfrog [Rana (Lithobates) catesbeiana] tadpoles. Archives of Environmental Contamination and Toxicology, 80: 735-744. DOI: 10.1007/s00244-021-00838-y.

Allison, M.J., Round, J.M., Bergman, L.C., Mirabzadeh, A., Allen, H., Weir, A., and Helbing, C.C. 2021. The effect of silica desiccation under different storage conditions on filter-immobilized environmental DNA. BMC Research Notes, 14: 106. DOI: 10.1186/s13104-021-05530-x.

Razmara, P., Imbery, J.J., Koide, E., Helbing, C.C., Wiseman, S.B., Gauthier, P.T., Bray, D., Needham, M., Haight, T., Zovoilis, A., and Pyle, G. 2021. Mechanism of copper nanoparticle toxicity in rainbow trout olfactory mucosa. Environmental Pollution, 284: 117141. DOI: 10.1016/j.envpol.2021.117141.


Chua, C.C., Brunswick, P., Kwok, H., Yan, J., Cuthbertson, D., van Aggelen, G., Helbing, C.C., and Shang, D. 2020. Enhanced analysis of weathered crude oils by gas chromatography-flame ionization detection, gas chromatography-mass spectrometry diagnostic ratios, and multivariate statistics. J Chromatography A, 1634: 461689. DOI: 10.1016/j.chroma.2020.461689.

Hobbs, J., Adams, I., Round, J.M., Allison, M.J., Goldberg, C.S., and Helbing, C.C. 2020. Extension of the Rocky Mountain tailed frog range in British Columbia, Canada using eDNA methods. Environmental DNA, 2, 350-361. DOI: 10.1002/edn3.82

Heerema, J.L., Bogart, S.J., Helbing, C.C., and Pyle, G.G. 2020. Ontogenetic changes in chemosensory structures and associated acuity in North American bullfrog (Rana [Lithobates] catesbeiana) tadpoles. Canadian Journal of Zoology, 98, 367-375. DOI: 10.1139/cjz-2019-0213

Kwok, H., Yan, J., Brunswick, P., McMaster, M., Evans, M., Kim, M, Helbing, C.C., Van Aggelen, G., and Shang, D. 2020. Ultra trace simultaneous determination of 50 polycyclic aromatic hydrocarbons in biota using pMRM GC-MS/MS. Environmental Forensics, 21, 87-98. DOI: 10.1080/15275922.2019.1693443

Klymus, K.E., Merkes, C.M., Allison, M.J., Goldberg, C.S., Helbing, C.C., Hunter, M.E., Jackson, C.A., Lance, R.F., Mangan, A.M., Monroe, E.M., Piaggio, A.J., Stokdyk, J.P., Wilson, C.C., and Richter, C. 2019. Reporting the limits of detection (LOD) and quantification (LOQ) for environmental DNA assays. Environmental DNA, 2, 271-282. DOI: 10.1002/edn3.29.


Helbing, C.C. and Hobbs, J. 2019. Environmental DNA standardization needs for fish and wildlife population assessments and monitoring. Canadian Standards Association, Toronto, ON. 41 pp. Link

Homola, J.J., Loftin, C.S., Cammen, K.M., Helbing, C.C., Birol, I., Schultz, T.F., and Kinnison, M.T. 2019. Replicated landscape genomics identifies evidence of local adaptation to urbanization in wood frogs. Journal of Heredity, esz041. DOI: 10.1093/jhered/esz041

Thambirajah, A.A., Koide, E.M., Imbery, J.J., and Helbing C.C. 2019. Contaminant and environmental influences on thyroid hormone action in amphibian metamorphosis. Frontiers in Endocrinology, 10: 276. DOI: 10.3389/fendo.2019.00276

Hobbs, J., Round, J.M., Allison, M.J., and Helbing, C.C. 2019. Expansion of the known distribution of the coastal tailed frog, Ascaphus truei, in British Columbia, Canada using robust eDNA detection methods. PLoS One, 14: e0213849. DOI: 10.1371/journal.pone.0213849

Luz, J.S., Caneguim, B.H., Baggio, A., Santoni, M., Helbing, C.C., Valentini, S.R., Sasso-Cerri, E., and Oliveira, C.C. 2019. Differential expression of RNA exosome subunits in amphibians. BMC Research Notes, 12: 46. DOI: 10.1186/s13104-019-4077-7

Imbery, J.J., Buday, C., Miliano, R.C., Shang, D., Round, J.M., Kwok, H., van Aggelen, G., and Helbing, C.C. 2019. Evaluation of gene bioindicators in the liver and caudal fin of juvenile Pacific coho salmon in response to low sulfur marine diesel seawater-accommodated fraction exposure. Environmental Science and Technology, 53: 1627–1638. DOI: 10.1021/acs.est.8b05429

Helbing, C.C., Hammond, S.A., Jackman, S.H., Houston, S., Warren, R.L., Cameron, C.E., and Birol, I. 2019. Antimicrobial peptides from Rana [Lithobates] catesbeiana: Gene structure and bioinformatic identification of novel forms from tadpoles. Scientific Reports, 9: 1529. DOI: 10.1038/s41598-018-38442-1


Hobbs, J. and Helbing, C.C. 2018. eDNA – Seeing the unseen. College Matters, 10: 13-14.

Park, G., Brunswick, P., Kwok, H., Haberl, M., Yan, J., MacInnis, C., Kim, M., Helbing, C., van Aggelen, G., and Shang, D. 2018. A rapid gas chromatograph tandem mass spectrometry method for the determination of 50 polycyclic aromatic hydrocarbons for application in a marine environment. Analytical Methods, 10: 5559. DOI: 10.1039/c8ay02258e

Jackman, K.W., Veldhoen, N., Miliano, R.C., Roberts, B.J., Li, L., Khojasteh, A., Zheng, X., Zaborniak, T.S.M., van Aggelen, G., Lesperance, M., Parker, W.J., Hall, E.R., Pyle, G.G., and Helbing, C.C. 2018. Transcriptomics investigation of thyroid hormone disruption in the olfactory system of the Rana [Lithobates] catesbeianatadpole. Aquatic Toxicology, 202: 46-56. DOI:10.1016/j.aquatox.2018.06.015.

Luehr, T.C., Koide, E.M., Wang, X., Han, J., Borchers, C.H., and Helbing, C.C. 2018. Metabolomic insights into the effects of thyroid hormone on metamorphosis in Rana [Lithobates] catesbeiana using whole-body Matrix assisted Laser Desorption/Ionization-Mass Spectrometry Imaging (MALDI-MSI). General and Comparative Endocrinology, pii: S0016-6480(17)30797-9. DOI: 10.1016/j.ygcen.2018.02.012.

Campbell, L., Hammond, S.A., Price, S., Sharma, M., Garner, T., Birol, I., Helbing, C.C., Bayer-Wilfert, L., and Griffiths, A. 2018. A novel approach to wildlife transcriptomics provides evidence of disease-mediated differential expression and changes to the microbiome of amphibian populations. Molecular Ecology, 1-15. DOI:10.1111/mec.14528.

Heerema, J.L., Helbing, C.C., and Pyle, G.G. 2018. Use of electro-olfactography to measure olfactory acuity in the North American bullfrog (Lithobates (Rana) catesbeiana) tadpole. Ecotoxicology and Environmental Safety, 147:643-647. DOI:10.1016/j.ecoenv.2017.09.014


Heerema, J.L., Jackman, K.W., Miliano, R.C., Li, L., Zaborniak, T.S.M., Veldhoen, N., van Aggelen, G., Parker, W.J., Pyle, G.G., and Helbing, C.C. 2017. Behavioral and molecular analyses of olfaction-mediated avoidance responses of Rana (Lithobates) catesbeiana tadpoles: Sensitivity to thyroid hormones, estrogen, and treated municipal wastewater effluent. Hormones and Behavior, 101: 85-93. DOI: 10.1016/j.yhbeh.2017.09.016.

Hammond, S.A., Warren, R.L., Vandervalk, B.P. Kucuk, E., Khan, H., Gibb, E.A., Pandoh, P., Kirk, H., Zhao, Y., Jones, M., Mungall, A.J., Pleasance, S., Moore, R.A., Holt, R.A., Round, J.M., Ohora, S., Walle, B.V., Veldhoen, N., Helbing, C.C., and Birol, I. 2017. North American bullfrog draft genome provides insight into hormonal regulation of long noncoding RNA. Nature Communications, 8: 1433. DOI: 10.1038/s41467-017-01316-7

Noël, M., Dangerfield, N.J., Jeffries, S., Lambourn, D., Lance, M., Helbing, C.C., Lebeuf, M., and Ross, P.S. 2017. Polychlorinated biphenyl-related alterations of the expression of essential genes in harbor seals (Phoca vitulina) from coastal sites in Canada and the United States. Archives of Environmental Contaminants and Toxicology 73: 310-321. DOI: 10.1007/s00244-016-0362-9.

Hammond, S.A., Warren, R.L., Vandervalk, B.P. Kucuk, E., Khan, H., Gibb, E.A., Pandoh, P., Kirk, H., Zhao, Y., Jones, M., Mungall, A.J., Pleasance, S., Moore, R.A., Holt, R.A., Round, J.M., Ohora, S., Walle, B.V., Veldhoen, N., Helbing, C.C., and Birol, I. 2017. It’s okay to be green: Draft genome of the North American bullfrog (Rana (Lithobates) catesbeiana). bioRxiv 100149;

Brown, T.M., Hammond, S.A., Behsaz, B., Veldhoen, N., Birol, I., and Helbing, C.C. 2017. De novo assembly of the ringed seal (Pusa hispida) blubber transcriptome: a tool that enables identification of molecular health indicators associated with PCB exposure. Aquatic Toxicology, 185: 48-57. DOI:10.1016/j.aquatox.2017.02.004

Huang, S.S.Y., Benskin, J.P., Veldhoen, N., Chandramouli, B., Butler, H., Helbing, C.C., and Cosgrove, J.R. 2017. A multi-omic approach to elucidate low-does effects of xenobiotics in zebrafish larvae (Danio rerio). Aquatic Toxicology, 182: 102-112. DOI:10.1016/j.aquatox.2016.11.016


Veldhoen, N., Hobbs, J., Ikonomou, G., Hii, M., Lesperance, M., and Helbing, C.C. 2016. Implementation of novel design features for qPCR-based eDNA assessment. PLoS One, 11: e0164907. DOI: 10.1371/journal.pone.0164907

Hansen, M., Luong, X., Sedlak, D.L., Helbing, C.C., and Hayes, T. 2016. Quantification of 11 thyroid hormones and associated metabolites in blood using isotope-dilution liquid chromatography tandem mass spectrometry. Analytical and Bioanalytical Chemistry 408: 5429-5442. DOI: 10.1007/s00216-016-9614-9(*PAPER IN FOREFRONT)

Huang, S.S.Y., Benskin, J.P., Chandramouli, B., Butler, H., Helbing, C.C., and Cosgrove, J.R. 2016. Xenobiotics produce distinct metabolomics responses in zebrafish larvae (Danio rerio). Environmental Science & Technology, 50: 6526-6535. DOI: 10.1021/acs.est.6b01128

Maher, S.K., Wojnarowicz, P., Ichu, T.-A., Veldhoen, N., Lu, L., Lesperance, M., Propper, C.R., and Helbing, C.C. 2016. Rethinking the biological relationships of the thyroid hormones, L-thyroxine and 3,5,3’-triiodothyronine. Comparative Biochemistry and Physiology Part D Genomics Proteomics, 18: 44-53. DOI: 10.1016/j.cbd.2016.04.002

Hammond, S.A., Jackman, K.W., Partovi, S., Veldhoen, N., and Helbing, C.C. 2016. Identification of organ-autonomous constituents of the molecular memory conferred by thyroid hormone exposure in cold temperature-arrested metamorphosing Rana (Lithobates) catesbeiana tadpoles. Comparative Biochemistry and Physiology Part D, 17: 58-65. DOI: 10.1016/j.cbd.2016.01.002

Hammond, S.A., Nelson, C.J., and Helbing, C.C. 2016. Environmental influences on the epigenomes of herpetofauna and fish. Biochemistry and Cell Biology, 94: 1-6. DOI: 10.1139/bcb-2015-0111

Dew, W.A., Veldhoen, N., Carew, A.C., Helbing, C.C., and Pyle, G.G. 2016. Cadmium-induces olfactory dysfunction in rainbow trout: Effects of binary and quaternary metal mixtures. Aquatic Toxicology, 172: 86-94. DOI: 10.1016/j.aquatox.2015.12.018


Veldhoen, N., Stevenson, M.R., and Helbing, C.C. 2015. Comparison of thyroid hormone-dependent gene responses in vivo and in organ culture of the American bullfrog (Rana (Lithobates) catesbeiana) lung. Comparative Biochemistry and Physiology Part D, 16: 99-105. DOI: 10.1016/j.cbd.2015.09.001

Birol, I., Behsaz, B., Hammond, S.A., Kuçuk, E., Veldhoen, N., and Helbing, C.C. 2015. De novo transcriptome assemblies of Rana (Lithobates) catesbeiana and Xenopus laevis tadpole livers for comparative genomics without reference genomes. PLoS One, 10 (6): e0130720.

Wolff, S.E., Ramirez, C.R., Coston, J.M., Veldhoen, N., Helbing, C.C., and Propper, C.R. 2015. Environmental contaminants alter the mRNA abundance profiles of genes involved in gonadal differentiation of the American bullfrog. Science of the Total Environment, 521-522: 380-387.

Brown, T.M., Iverson, S.J., Fisk, A.T., Macdonald, R.W., Helbing, C.C., and Reimer, K.J. 2015. Local contamination and not feeding preferences explain elevated PCB concentrations in Labrador ringed seals (Pusa hispida). Science of the Total Environment, 515-516:188-197.

Hammond, S.A., Veldhoen, N., and Helbing, C.C. 2015. Influence of temperature on thyroid hormone signaling and endocrine disruptor action in Rana (Lithobates) catesbeiana tadpoles. General and Comparative Endocrinology, 219: 6-15.


Carew, A.C., Hoque, M.E., Metcalfe, C.D., Peyrot, C., Wilkinson, K.J., and Helbing, C.C. 2014. Chronic sublethal exposure to silver nanoparticles disrupts thyroid hormone signaling during Xenopus laevis metamorphosis. Aquatic Toxicology, 159C:99-108.

Brown, T.M., Luque, S., Sjare, B., Fisk, A.T., Helbing, C.C., and Reimer, K.J. 2014. Satellite telemetry informs PCB source apportionment in a mobile, high trophic level marine mammal- the ringed seal (Pusa hispida). Environmental Science and Technology, accepted.

Brown, T.M., Ross, P.S., Reimer, K.J., Veldhoen, N., Dangerfield, N.J., Fisk, A.T., and Helbing, C.C. 2014. PCB related effects thresholds as derived through gene transcript profiles in locally contaminated ringed seals (Pusa hispida). Environmental Science and Technology, accepted.

Benskin, J.P., Ikonomou, M.G., Liu, J., Veldhoen, N., Dubetz, C., Helbing, C.C., and Cosgrove, J.R. 2014. Distinctive metabolite profiles in in-migrating Sockeye salmon suggest sex-linked endocrine perturbation. Environmental Science and Technology, accepted.

Brown, T.M., Fisk, A.T., Helbing, C.C., and Reimer, K.J. 2014. PCB profiles in ringed seals (Pusa hispida) reveal historical contamination by a military radar station in Labrador, Canada. Environmental Toxicology and Chemistry, 33, 592-601.

Ichu, T.-A., Han, J., Borchers, C., Lesperance, M., and Helbing, C.C. 2014. Metabolomic insights into system-wide coordination of vertebrate metamorphosis. BMC Devel Biology, 14, 5.

Noël, M., Loseto, L.L., Helbing, C.C., Veldhoen, N., Dangerfield, N.J., and Ross, P.S. 2014. When threats converge: Do both PCBs and climate change alter gene transcript profiles in Arctic beluga whales? Environmental Science and Technology, 48, 5.

Osachoff, H.L., Mohammadali, M., Skirrow, R.C., Hall, E.R., Brown, L.L., van Aggelen, G.C., Kennedy, C.J., and Helbing, C.C. 2014. Evaluating the treatment of a synthetic wastewater containing a pharmaceutical and personal care product cocktail: compound removal efficiency and effects on juvenile rainbow trout. Water Research, 62, 271-280.

Veldhoen, N., Beckerton, J.E., Stevenson, M.R., Truelson, R.L., and Helbing, C.C. 2014. Development of transcriptomic endpoints in Arctic grayling (Thymallus arcticus) associated with environmental monitoring of regional mining activities in the Yukon Territory. Ecotoxicology and Environmental Safety, 105, 43-50.

Veldhoen, N., Propper, C.R., and Helbing, C.C. 2014. Enabling comparative gene expression studies of thyroid hormone action through the development of a flexible real-time quantitative PCR assay for use across multiple anuran indicator and sentinel species. Aquatic Toxicology, 148, 162-173.

Veldhoen, N., Skirrow, R.C., Brown, L., van Aggelen, G., and Helbing, C.C. 2014. Effects of acute exposure to the non-steroidal anti-inflammatory drug, ibuprofen, on the developing North American bullfrog (Rana catesbeiana) tadpole. Environmental Science and Technology, 48, 10439-10447.

Wojnarowicz, P., Yang, W., Zhou, H., Parker, W.J., and Helbing, C.C. 2014. Hormone and stress-inducing activities of municipal wastewater along successive units of a full-scale conventional activated sludge plant. Water Research, 66C:265-272.


Boone, M.D., Hammond, S.A., Veldhoen, N., Youngquist, M., and Helbing, C.C. 2013. Exposure time during postembryonic development influences persistent biological effects of the insecticide carbaryl in green frogs (Lithobates clamitans). Aquatic Toxicology, 130-131:139-48.

Brown, T.M., Fisk, A.T., Helbing, C.C., and Reimer, K.J. 2013. PCB profiles in ringed seals (Pusa hispida) reveal historical contamination by a military radar station in Labrador, Canada. Environmental Toxicology and Chemistry, DOI: 10.1002/etc.2468.

Haberl, M., Shang, D., Skirrow, R.C., Helbing, C.C., Marlatt, V.L., and van Aggelen, G.C. 2013. Development of a rapid liquid chromatography tandem mass spectrometry method for determination of triclosan in tissue matrices. Separation Science, 5, 13-19.

Hammond, S.A., Carew, A.C., and Helbing, C.C. 2013. Evaluation of the effects of titanium dioxide nanoparticles on cultured Rana catesbeiana tail fin tissue. Frontiers in Genetics, 4:251. DOI: 10.3389/fgene.2013.00251

Hammond, S.A., Veldhoen, N., Kobylarz, M., Webber, N.R., Jordan, J., Rehaume, V., Boone, M.D., and Helbing, C.C. 2013. Characterization of gene expression endpoints during postembryonic development of the northern green frog (Rana clamitans melanota). Zoological Science, 30, 392-401.

Johansson, F., Veldhoen, N., Lind, M.I., and Helbing, C.C. 2013. Phenotypic plasticity in the hepatic transcriptome of the European common frog (Rana temporaria): the interplay between environmental induction and geographical lineage on developmental response. Molecular Ecology, 22: 5608-5623. DOI: 10.1111/mec.12497

Marlatt, V.L., Veldhoen, N., Lo, B.P., Bakker, D., Rehaume, V., Vallée, K., Haberl, M., Shang, D., Elphick, J. and Helbing, C.C. 2013. Triclosan exposure alters postembryonic development in a Pacific Tree Frog (Pseudacris regilla) amphibian metamorphosis assay (TREEMA). Aquatic Toxicology, 126: 85-94.

Veldhoen, N., Rehaume, V., Ikonomou, M.G., Dubetz, C., Patterson, D.A. and Helbing, C.C. 2013. Evidence of disruption in estrogen-associated signaling in the liver transcriptome of in-migrating sockeye salmon of British Columbia, Canada. Comparative Biochemistry and Physiology C, 157: 150-161.

Veldhoen, N., Stevenson, M.R., Skirrow, R.C., Rieberger, K.J., van Aggelen, G., Meays, C.L., and Helbing, C.C. 2013. Minimally invasive transcriptome profiling in salmon: Detection of biological response in rainbow trout caudal fin following exposure to environmental chemical contaminants. Aquatic Toxicology, 142-143C, 239-247.

Wojnarowicz, P., Olumuyiwa, O.O., Xia, C., Parker, W., and Helbing, C.C. 2013. Impact of wastewater treatment configuration and seasonal conditions on thyroid hormone disruption and stress effects in Rana catesbeiana tailfin. Environmental Science & Technology, 47: 13840-7.


Helbing, C.C. 2012. The metamorphosis of amphibian toxicogenomics. Frontiers in Genetics, 3: 37.

Hinther, A., Edwards, T.M., Guillette, L.J. Jr., and Helbing, C.C. 2012. Influence of nitrate and nitrite on thyroid hormone-responsive TRß or RLKI and stress-associated HSP30 or CAT expression in cultured Rana catesbeiana tadpole tail fin tissue. Frontiers in Genetics, 3: 51.

Searcy, B.T., Beckstrom-Sternberg, S.M., Beckstrom-Sternberg, J.S., Staford, P., Schwendiman, A.L., Soto-Peña, J., Owen, M.C., Ramirez, C., Phillips, J., Veldhoen, N., Helbing, C.C., and Propper, C.R. 2012. Thyroid hormone dependent development in Xenopus laevis. A sensitive screen of thyroid hormone signaling disruption by municipal wastewater treatment plant effluent. General and Comparative Endocrinology, 176: 481-492.

Veldhoen, N., Buday, C., Dubetz, C., Jordan, J., Rehaume, V., Cabecinha, M., Ikonomou, M.G., van Aggelen, G., and Helbing, C.C. 2012. The anti-parasitic chemotherapeutant emamectin benzoate is not biologically inert with respect to a non-target crustacean the spot prawn (Pandalus platycerosBrandt, 1851). Aquatic Toxicology, 108: 94-105.

Veldhoen, N., Ikonomou, M.G., and Helbing, C.C. 2012. Molecular profiling of marine fauna: Integration of omics with environmental assessment of the world’s oceans. Ecotoxicology and Environmental Safety, 76: 23-38.


Buckman, A.H., Veldhoen, N., Ellis, G., Ford, J.K.B., Helbing, C.C., and Ross, P.S. 2011. Association of endogenous PCB levels with mRNA expression endpoints in free-ranging killer whales (Orcinus orca). Environmental Science & Technology, 45: 10194-10202.

Gunderson, M.P., Veldhoen, N., Skirrow, R.C., Macnab, M.K., Ding, W., van Aggelen, G., and Helbing, C.C. 2011. Effect of low dose exposure to the herbicide atrazine and its metabolite on cytochrome P450 aromatase and steroidogenic factor-1 mRNA levels in the brain of premetamorphic bullfrog tadpoles (Rana catesbeiana). Aquatic Toxicology, 102: 31-8.

Helbing, C.C., Propper, C. and Veldhoen, N. 2011. Triclosan affects the thyroid axis of amphibians. Letter to Editor. Toxicological Science, Aug 18 Epub ahead of print PMID: 21852691.

Helbing, C.C., Wagner, M.J., Pettem, K., Johnston, J., Heimeier, R.A., Mu, R., Veldhoen, N., Lesperance, M., Jirik, F.R., Shi, Y.-B., and Browder, L.W. 2011. Modulation of thyroid hormone-dependent metamorphosis inXenopus laevis by Inhibitor of Growth (ING) proteins. PLoS One, 6: e28658.

Helbing, C.C., Wulff, J.E., Bromba, C.M., Hinther, A., and Veldhoen, N. 2011. Reply to comment on Effects of triclocarban, triclosan, and methyl-triclosan on thyroid hormone action and stress in frog and mammalian culture systems. Environmental Science & Technology, 45: 7600-1.

Hinther, A., Bromba, C.M., Wulff, J.E., and Helbing, C.C. 2011. Effects of triclocarban, triclosan, and methyl-triclosan on thyroid hormone action and stress in frog and mammalian culture systems. Environmental Science & Technology, 44: 5395-402.

Helbing, C.C., van Aggelen, G. and Veldhoen, N. 2011. Triclosan affects thyroid hormone-dependent metamorphosis in anurans. Letter to Editor. Toxicological Science, 119: 417-8.

Veldhoen, N., Kobylarz, M., Lowe, C.J., Meloche, L., de Bruyn, A., and Helbing, C.C. 2011. Relationship between mRNA biomarker candidates and location near a marine municipal wastewater outfall in the benthic indicator species Modiolous modiolous (L.). Aquatic Toxicology, 105: 119-26.


Esterhuyse, M.M., Helbing, C.C., and van Wyk, J.H. 2010. Isolation and characterization of three estrogen receptor transcripts in Oreochromis mossambicus (Peters). J. Steroid Biochem. Mol. Biol., 119: 26-34.

Helbing, C.C., Maher, S.K., Han, J., Gunderson, M.P., and Borchers, C. 2010. Peering into molecular mechanisms of action with frogSCOPE. General and Comparative Endocrinology, 168: 190-198.

Hinther, A., Domanski, D., Vawda, S., and Helbing, C.C. 2010. C-fin: A cultured frog tadpole tail fin biopsy approach for detection of thyroid hormone-disrupting chemicals. Environmental Toxicology and Chemistry, 29: 380-388.

Hinther, A., Vawda, S., Skirrow, R.C., Veldhoen, N., Collins, P., Cullen, J.T., van Aggelen, G., and Helbing, C.C. 2010. Nanometals induce stress and alter thyroid hormone action in amphibian at or below North American water quality guidelines. Environmental Science & Technology, 44: 8314-8321.

Veldhoen, N., Ikonomou, M.G., Dubetz, C., MacPherson, N., Sampson, T., Kelly, B.C. and Helbing, C.C. 2010. Gene expression profiling and environmental contaminant assessment of migrating Pacific salmon in the Fraser River watershed of British Columbia. Aquatic Toxicology, 97: 212-225.


Dryhurst, D., Ishibashi, T., Rose, K.L., Eirin-Lopez, J.M., McDonald, D., Silva-Moreno, B., Veldhoen, N., Helbing, C.C., Hendzel, M.J., Shabanowitz, J., Hunt, D.F., and Ausió, J. 2009. Characterization of the histone H2A.Z-1 and H2A.Z-2 isoforms in vertebrates. BMC Biology, 7: 86.

Esterhuyse, M.M., Venter, M., Veldhoen, N., Helbing, C.C., and J.H. van Wyk. 2009. Characterization of vtg-1 mRNA expression during ontogeny in Oreochromis mossambicus (Peters). J. Steroid Biochem. Mol. Biol., 119: 26-34.

Maher, S.K. and C.C. Helbing. 2009. Modulators of Inhibitor of Growth (ING) family expression in development and disease. Current Drug Targets, 10: 392-405.

Van Aggelen, G., Ankley, G., Baldwin, W., Bearden, D., Benson, W., Chipman, J., Collette, T., Craft, J., Denslow, N., Embry, M., Falciani, F., George, S., Helbing, C., Hoekstra, P., Iguchi, T., Kagami, Y., Katsiadaki, I., Kille, P., Liu, L., Lord, P., McIntyre, T., O’Neill, A., Osachoff, H., Perkins, E., Santos, E., Skirrow, R., Snape, J., Tyler, C., Versteeg, D., Viant, M., Volz, D., Williams, T. and Yu, L. 2009. Integrating omic technologies into aquatic ecological risk assessment and environmental monitoring: Hurdles, achievements and future outlook. Environmental Health Perspectives, 18:1-5.

Veldhoen, N., Lowe, C., Davis, C., Mazumder, A. and Helbing, C.C. 2009. Gene expression profiling in the deep water horse mussel Modiolus modiolus (L.) located near a marine municipal wastewater outfall. Aquatic Toxicology, 93: 116-124.


Esterhuyse, M.M., Helbing, C.C., and J.H. van Wyk. 2008. Temporal expression of two cytochrome P450 aromatase isoforms during development in Oreochromis mossambicus, in association with histological development. Comparative Biochemistry and Physiology Part D, 3: 297-306.

Skirrow, R.C., Veldhoen, N., Domanski, D. and C.C. Helbing. 2008. Roscovitine inhibits thyroid hormone-induced tail regression of the frog tadpole and reveals a role for phosphorylation in the establishment of the gene expression program. Developmental Dynamics, 237: 3787-3797.

Wagner, M.J. and C.C. Helbing. Characterization of the Inhibitor of Growth ING1 and ING2 gene promoters in Xenopus laevis. 2008. Biochemica Biophysica Acta: Gene Regulatory Mechanisms, 1779:152-163.

Walzak, A.A., Veldhoen, N., Feng, X., Riabowol, K., and C. C. Helbing. 2008. Expression profiles of mRNA transcript variants encoding the human Inhibitor of Growth tumour suppressor gene family in normal and neoplastic tissues. Experimental Cell Research, 314:273-85.


Domanski, D. and C.C. Helbing. 2007. Analysis of the Rana catesbeiana tadpole tail fin proteome and phosphoproteome during T3-induced apoptosis: Identification of a novel type I keratin. BMC Developmental Biology, 7:94.

Helbing, C.C., Bailey, C.M., Ji, L., Gunderson, M.P, Zhang, F., Veldhoen, N., Mu, R., Lesperance, M., Holcombe, G.W., Kosian, P.A., Tietge, J., Korte, J.J., and S.J. Degitz. 2007. Identification of gene expression indicators for thyroid axis disruption in a Xenopus laevis metamorphosis screening assay Part 1: Effects on the brain. Aquatic Toxicology, 82, 227-241.

Helbing, C.C., Crump, K., Bailey, C.M., Kohno, S., Veldhoen, N., Song, Y., Bermudez, D.S., Bryan, T., Ausió, J. and L.J. Guillette, Jr. 2007. Characterization of Inhibitor of Growth 2 tumor suppressor in Alligator mississippiensis, its conservation in Archosauria, and response to thyroid stimulating hormone. Comparative Biochemistry and Physiology B, 146, 279-288.

Helbing, C.C., Ji, L., Bailey, C.M., Veldhoen, N., Zhang, F., Holcombe, G.A., Kosian, P.A., Tietge, J., Korte, J.J., and S. J. Degitz. 2007. Identification of gene expression indicators for thyroid axis disruption in a Xenopus laevismetamorphosis screening assay Part 2: Effects on the tail and hindlimb. Aquatic Toxicology, 82, 215-226.

Ji, L., Domanski, D., Skirrow, R.C., and C. C. Helbing. 2007. Genistein prevents protein kinase C and thyroid hormone receptor alpha phosphorylation during thyroid hormone-dependent tail regression of Rana catesbeiana tadpoles. Developmental Dynamics, 236, 777-790.

Skirrow, R.C. and C.C. Helbing. 2007. Decreased cyclin dependent kinase activity promotes thyroid hormone-dependent tail regression in Rana catesbeiana. Cell Tissue Research, 328, 281-289.


Helbing, C.C., Ovaska, K., and L. Ji. 2006. Evaluation of the effect of acetochlor on thyroid hormone receptor gene expression in the brain and behavior of Rana catesbeiana tadpoles. Aquatic Toxicology, 80, 42-51.

Tabuchi, M., Veldhoen, N., Dangerfield, N., Jeffries, S., Helbing, C.C. and P.S. Ross. 2006. PCB-related alteration of thyroid hormone and their receptor alpha gene expression in free-ranging harbor seals (Phoca vitulina). Environmental Health Perspectives, 114, 1024-1031.

Veldhoen, K., Allison, W.T., Veldhoen, N., Anholt, B.R., Helbing, C.C. and Hawryshyn, C.W. 2006. Spatio-temporal characterization of retinal opsin gene expression during thyroid hormone-induced and natural development of rainbow trout. Visual Neuroscience 23, 169-179.

Veldhoen, N., Boggs, A., Walzak, K. and C. C. Helbing. 2006. Exposure to tetrabromobisphenol-A alters TH-Associated gene expression and tadpole metamorphosis in the Pacific tree frog Pseudacris regilla. Aquatic Toxicology, 78, 292-302.

Veldhoen, N., Skirrow, R.C., Ji, L., Domanski, D., Bonfield, E.R., Bailey, C.M. and C.C. Helbing. 2006. Use of heterologous cDNA arrays and organ culture in the detection of thyroid hormone-dependent responses in sentinel frog species. Comparative Biochemistry and Physiology D, 1, 187-199.

Veldhoen, N., Skirrow, R.C., Osachoff, H., Wigmore, H., Clapson, D.J., Gunderson, M.P., Van Aggelen, G., and Helbing, C.C. 2006. The bactericidal agent Triclosan modulates thyroid hormone-associated gene expression and disrupts postembryonic anuran development. Aquatic Toxicology, 80, 217-227.

Zhang, F., Degitz, S.J., Holcombe, G.W., Kosian, P.A., Tietge, J., Veldhoen, N., and C.C. Helbing. 2006. Evaluation of gene expression endpoints in the context of a Xenopus laevis metamorphosis-based bioassay to detect thyroid hormone disruptors. Aquatic Toxicology 76, 24-36.


He, G.H.Y., Helbing, C.C., Wagner, M.J., Sensen, C.W. and K. Riabowol. 2005. Phylogenetic analysis of the ING family of PHD finger proteins. Molecular Biology and Evolution 22, 104-116.

Wagner, M.J. and C.C. Helbing. 2005. Multiple variants of ING1 and 2 are differentially expressed and thyroid hormone-responsive in Xenopus laevis. General and Comparative Endocrinology 144:38-50.

Veldhoen, N. and Helbing, C. 2005. Monitoring gene expression on Rana catesbeiana tadpoles using a tail fin biopsy technique and its application to the detection of environmental endocrine disruptor effects, in: Techniques in Aquatic Toxicology: Vol. 2 (G. Ostrander, ed.), pp. 315-327, Taylor & Francis, Boca Raton, FL.


Howe, C.M., Berrill, M., Pauli, B.D., Helbing, C.C., Werry, K. and Veldhoen, N. 2004. Toxicity of glyphosate-based pesticides to four North American frog species. Environmental Toxicology and Chemistry 23, 1928-1938.

Katsu, Y., Bermudez, D.S., Braun, E., Helbing, C.C., Miyagawa, S., Gunderson, M.P., Kohno, S., Bryan, T.A., Guillette Jr., L.J. and T. Iguchi. 2004. Molecular cloning of the estrogen and progesterone receptors of the American alligator. General and Comparative Endocrinology 136, 122-133.


Helbing, C.C., Werry, K., Crump, D., Domanski, D., Veldhoen, N. and Bailey, C.M. 2003. Expression profiles of novel thyroid hormone-responsive genes and proteins in the tail of Xenopus laevis tadpoles undergoing precocious metamorphosis. Molecular Endocrinology 17, 1395-1403.


Crump, D., Werry, K., Veldhoen, N., van Aggelen, G. and C.C. Helbing. 2002. Exposure to the herbicide acetochlor alters thyroid hormone-dependent gene expression and metamorphosis in Xenopus laevis. Environmental Health Perspectives 110, 1199-1205.

Veldhoen, N., Crump, D., Werry, K. and C.C. Helbing. 2002. Distinctive gene profiles occur at key points during natural metamorphosis in the Xenopus laevis tadpole tail. Developmental Dynamics 225, 457-468.


Wagner, M.J., Gogela-Spehar, M., Skirrow, R.C., Johnston, R.N., Riabowol, K.T. and Helbing, C.C. 2001. Expression of novel ING variants is regulated by thyroid hormone in the Xenopus laevis tadpole. J Biol Chemistry 276, 47013-47020.

Veldhoen, N. and C. Helbing, 2001. Detection of environmental endocrine disruptor effects on gene expression in live Rana catesbeiana tadpoles using a tail fin biopsy technique. Environmental Toxicology and Chemistry 20, 2704-2708.