Mr Tony Rothkirch

Professional Officer

Research Services

Career Summary


  • Agricultural Science
  • Environmental science
  • Veterinary Science

Fields of Research

040399Geology not elsewhere classified15
050299Environmental Science and Management not elsewhere classified50
090799Environmental Engineering not elsewhere classified35


For publications that are currently unpublished or in-press, details are shown in italics.

Journal article (10 outputs)

2014Aitken RJ, Finnie JM, Muscio L, Whiting S, Connaughton HS, Kuczera L, et al., 'Potential importance of transition metals in the induction of DNA damage by sperm preparation media', Human Reproduction, 29 2136-2147 (2014) [C1]

STUDY QUESTION: What are the mechanisms by which the preparation of spermatozoa on discontinuous density gradients leads to an increase in oxidative DNA damage? SUMMARY ANSWER: The colloidal silicon solutions that are commonly used to prepare human spermatozoa for assisted reproduction technology (ART) purposes contain metals in concentrations that promote free radical-mediated DNA damage. WHAT IS KNOWN ALREADY: Sporadic reports have already appeared indicating that the use of colloidal silicon-based discontinuous density gradients for sperm preparation is occasionally associated with the induction of oxidative DNA damage. The cause of this damage is however unknown. STUDY DESIGN, SIZE, DURATION: This study comprised a series of experiments designed to: (i) confirm the induction of oxidativeDNA damage in spermatozoa prepared on commercially available colloidal silicon gradients, (ii) compare the levels of damage observed with alterative sperm preparation techniques including an electrophoretic approach and (iii) determine the cause of the oxidative DNA damage and develop strategies for its prevention. The semen samples employed for this analysis involved a cohort of >50 unselected donors and at least three independent samples were used for each component of the analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: The setting was a University biomedical science laboratory. The major techniques employed were: (i) flow cytometry to study reactive oxygen species generation, lipid peroxidation and DNA damage, (ii) computeraided sperm analysis to measure spermmovement and (iii) inductively coupled mass spectrometry to determine the elemental composition of sperm preparation media. MAIN RESULTS AND THE ROLE OF CHANCE: Oxidative DNA damage is induced in spermatozoa prepared on PureSperm® discontinuous colloidal silicon gradients (P < 0.001 versus repeated centrifugation) because this medium contains metals, particularly Fe, Al and Cu, which are known to promote free radical generation in the immediate vicinity of DNA. This damage can be significantly accentuated by reducing agents, such as ascorbate (P < 0.001) and inhibited by selective chelation (P < 0.001). This problem is not confined to PureSperm®; analysis of additional commercial sperm preparation media revealed that metal contamination is a relatively constant feature of such products. LIMITATIONS, REASONS FOR CAUTION: While the presence of metals, particularly transition metals, may exacerbate the levels of oxidative DNA damage seen in human spermatozoa, the significance of such damage has not yet been tested in suitably powered clinical trials. WIDER IMPLICATIONS OF THE FINDINGS: The results explain why the preparation of spermatozoa on discontinuous colloidal silicon gradients can result in oxidative DNA damage. The results are of immediate relevance to the development of safe, effective protocols for the preparation of spermatozoa for ART purposes. STUDY FUNDING/COMPETING INTEREST(S): The studywas funded by the Australian Health and Medical ResearchCouncil. One of the authors (R.J.A.) has had a consultantship with a biotechnology company, NuSep, interested in the development of electrophoretic methods of sperm preparation. He has no current financial interest in this area. None of the other authors have a conflict of interest to declare.

Co-authorsJohn Aitken, Geoffry DeiuliIs
2011Dunstan RH, Ho P-H, Adams MC, Rothkirch TB, Roberts TK, 'Opioid peptide digestion by newly isolated potential probiotic bacteria from foods', Journal of Science and Technology, 49 161-168 (2011)
Co-authorsHugh Dunstan, Tim Roberts
2011Dunstan RH, Sparkes DL, MacDonald MM, Roberts TK, Wratten C, Kumar M, et al., 'Altered amino acid homeostasis and the development of fatigue by breast cancer radiotherapy patients: A pilot study', Clinical Biochemistry, 44 208-215 (2011) [C1]
CitationsScopus - 3Web of Science - 2
Co-authorsTim Roberts, Surinder Baines, Hugh Dunstan, Diane Sparkes
2008Evans CA, Dunstan RH, Rothkirch TB, Roberts TK, Reichelt KL, Cosford RE, et al., 'Altered amino acid excretion in children with autism', Nutritional Neuroscience, 11 9-17 (2008) [C1]
CitationsScopus - 18Web of Science - 16
Co-authorsTim Roberts, Hugh Dunstan, Diane Sparkes
2007Niblett SH, King KE, Dunstan RH, Clifton-Bligh P, Hoskin LA, Roberts TK, et al., 'Hematologic and urinary excretion anomalies in patients with chronic fatigue syndrome', Experimental Biology and Medicine, 232 1041-1049 (2007) [C1]
CitationsScopus - 10Web of Science - 8
Co-authorsHugh Dunstan, Tim Roberts, Katrina King
2007Shah V, Dunstan RH, Geary PM, Coombes PJ, Roberts TK, Rothkirch TB, 'Bacterial source tracking from diverse land use catchments by sterol ratios', Water Research, 41 3667-3674 (2007) [C1]
CitationsScopus - 5Web of Science - 4
Co-authorsTim Roberts, Phil Geary, Hugh Dunstan
2007Shah V, Dunstan RH, Geary PM, Coombes PJ, Roberts TK, Rothkirch TB, 'Comparisons of water quality parameters from diverse catchments during dry periods and following rain events', Water Research, 41 3655-3666 (2007) [C1]
CitationsScopus - 28Web of Science - 19
Co-authorsTim Roberts, Phil Geary, Hugh Dunstan
2006Geary PM, Shah V, Dunstan RH, Coombes PJ, Rothkirch TB, 'Tracing faecal contributions from on-site wastewater systems', Water, 33 48-51 (2006) [C1]
CitationsScopus - 4
Co-authorsHugh Dunstan, Phil Geary
2000Dunstan RH, McGregor NR, Roberts TK, Butt HL, Niblett SH, Rothkirch TB, 'The development of laboratory-based tests inchronic pain fatigue. 1. Muscle catabolism and coagulase negative staphylococci which produce membrane damaging toxins', JOURNAL OF CHRONIC FATIGUE SYNDROME, 7, NO. 2 53-57 (2000) [C1]
Co-authorsTim Roberts, Hugh Dunstan
2000Dunstan RH, McGregor NR, Butt HL, Roberts TK, Klineberg IJ, Niblett SH, et al., 'Characterization of differential amino acid homeostasis amongst population subgroups: A basis for determining specific amino acid requirements', JOURNAL OF NUTRITIONAL & ENVIRONMENTAL MEDICINE, 10 211-223 (2000) [C1]
CitationsScopus - 5
Co-authorsHugh Dunstan, Tim Roberts
Show 7 more journal articles

Conference (4 outputs)

2007Bromley AR, Dunstan RH, Roberts TK, Rothkirch TB, Kiernan HL, Hodgson DM, 'Early life determinants of the effects of anandamide on circulating amino acids and corticosterone levels in adulthood', Early Human Development, Perth (2007) [E3]
Co-authorsTim Roberts, Deborah Hodgson, Hugh Dunstan
2005Geary PM, Shah V, Dunstan RH, Coombes PJ, Rothkirch TB, 'Bacterial source tracking methods to distinguish between fecal contributions from on-site wastewater systems', On-Site 05 Conference : performance assessment for on-site systems: regulation, operation, and monitoring, Armidale, NSW (2005) [E3]
Co-authorsPhil Geary, Hugh Dunstan
2005Geary PM, Shah V, Dunstan RH, Coombes PJ, Rothkirch TB, 'Bacterial Source Tracing Methods to Distinguish Between Faecal Contributions from On-Site Wastewater Systems', Proceedings of the Performance Assessment for On-Site Systems: Regulation, operation and monitoring conference, University of New England, Armidale, Australia (2005) [E1]
Co-authorsPhil Geary, Hugh Dunstan
2003Bromley AR, Roberts TK, Dunstan RH, Rothkirch TB, Kiernan HL, Hodgson DM, 'Prenatal exposure to LPS Alters Development of the Endocannabinoid System in the Rodent', The Endocrine Society of Australia Proceedings 2003, Melbourne, Victoria (2003) [E3]
Co-authorsHugh Dunstan, Deborah Hodgson, Tim Roberts
Show 1 more conference

Mr Tony Rothkirch


Professional Officer
Analytical & Biomolecular Research Facility (ABRF)
Research Services
Research and Innovation Division

Contact Details
Phone(02) 4921 7813
Fax(02) 4921 7299


BuildingLife Sciences Building
University Drive
Callaghan, NSW 2308