Jo-Anne R. Dillon, Ph.D.

Professor, Department of Microbiology and Immunology
Associate Member, Department of Biology
Member, College of Graduate Studies and Research
Research Scientist, Vaccine and Infectious Disease Organization
University of Saskatchewan
120 Veterinary Road
Saskatoon, SK S7N 5E3
Telephone: (306) 966-1535
Fax: (306) 966-7478

Bacterial biology and antimicrobials

Laboratory address:
Rm A233, 120 Veterinary Road
Vaccine and Infectious Disease Organization
University of Saskatchewan
Saskatoon, SK S7N 5E3
Tel: (306) 966-1553

Lab members. June 2004, Ottawa
Front (from left): M. Liao, P. Cebulski, L. Lapointe-Shaw.
Middle (from left): C. Stafford, M. Rigden, P. Ruddock, H. Li, J.R. Dillon.
Rear (from left): D. Sikora, S. Acharya, N.F. Eng, S. Martharler, V. Greco. (Absent: J. Szeto)

Lab members from left (Saskatoon, September 1, 2010):
Front: G. Liu, A. Storey, J.R. Dillon, R. Parti
Middle : S. Vidovic, A. Havaei, Y. Li, M. Liao
Back: S. Dev, S. Starnino

Laboratory members:


Neisseria gonorrhoeae (Ng) FtsZ-GFP fusion forms a band in the middle of Escherichia coli cells. (Adapted from Salimnia, et al. 2000. Arch. Microbiol. 173:10-20).

Time-lapse fluorescence microscopy shows GFP fused gonococcal cell division protein MinD oscillation along the long axis in round E. coli cells. (Adapted from Ramirez-Arcos, et al. Mol. Microbiol. 46:493-504, 2002).

Research in the Dillon laboratory has focused in three major areas:

International Collaboration on Gonoccoci site -

Bacterial Cell Division:

Our laboratory has pioneered the study of cell division in Neisseria gonorrhoeae, a round Gram-negative microorganism that divides in alternating perpendicular planes. Using an array of methods, including genomics, bioinformatics, biochemistry, structural modeling, molecular microbiology and fluorescence microscopy, we identified and characterized the gene organization of both the division cell wall (dcw) cluster as well as the min cluster which includes the min genes- minC, minD and minE, responsible for midcell site selection. How round cells identify the midcell and initiate the cascade of division pathway is complex. Many key cell division proteins move within the cell and contribute to bacterial subcellular architecture. Using targeted mutagenesis to alter structure we have been able to ascertain important functional domains on the Min proteins. We will continue to focus on the role of proteins contributing to the subcellular architecture of bacteria by studying their biomolecular interactions through various cell-based analyses to unravel the myriad interconnected pathways of bacterial cell division.

We also study cell division in Gram-positive round bacteria, such as Enterococcus faecalis. In some Gram-positive bacteria such as B. subtilis, DivIVA replaces MinE and acts with MinC and MinD to specify the division site. We have identified a DivIVA homologue in Enterococcus faecalis, a bacterium that lacks any Min proteins. DivIVA from E. faecalis is essential and plays important roles in chromosomal segregation. A novel DivIVA binding protein in E. faecalis has also been identified. This novel protein is conserved in Gram-positive bacteria including B. subtilis and is involved in bacterial cell division. Current studies are focusing on the role of DivIVA-related protein complex in the cell division mechanisms of Gram-positive bacteria lacking Min proteins.

Antimicrobial Resistance and Natural Products:

Our laboratory has investigated antibiotic-resistance in bacteria for over 25 years. We have especially focused on resistance surveillance, molecular epidemiology and resistance mechanisms of Neisseria gonorrhoeae. Our research programs have included the leadership of the Gonococcal Antimicrobial Surveillance Program in the Americas and Caribbean, the genetics of arginine auxotrophy, the molecular biology and genomics of gonococcal penicillinase-producing plasmids, methods of molecular typing and more. Working in collaboration with medicinal chemists and the researchers of ethnopharmacology and medicinal plants at the University of Ottawa, we have studied the antimicrobial properties of various natural products (e.g. Canadian botanicals, garlic), in order to identify novel antimicrobial agents.

Selected publications

  1. R.P. Parti, M.A. Horbay, M. Liao and J.R. Dillon. Regulation of minD by oxyR in Neisseria gonorrhoeae. Res. Microbiol. In Press.
  2. S. Vidovic, S. Thakur, G. Horsman, P. Levett, V. Anvari, and J.R. Dillon. 2012. Longitudinal analysis of the evolution and dissemination of Neisseria gonorrhoeae strains (Saskatchewan, Canada, 2005 to 2008) reveals three major circulating strains and convergent evolution of ciprofloxacin and azithromycin resistance.  J. Clin. Microbiol. 50 (12): 3823-3830.
  3. S. Starnino, GASP-LAC Working Group, P. Galarza, M.E. Trigoso Carvallo, A. Schwartz Benzaken, A. Maldonado Ballesteros, O.M. Sanabria Cruz, A. Llop Hernandez, J.L. Portilla Carbajal, G. Borthagaray, D. Payares, J.R. Dillon. 2012. Retrospective analysis of antimicrobial susceptibility trends (2000-2009) in Neisseria gonorrhoeae isolates from countries in Latin America and the Caribbean shows evolving resistance to ciprofloxacin, azithromycin and decreased susceptibility to ceftriaxone. Sex. Transm. Dis. 39 (10): 813-821.
  4. J.R. Dillon and R.P. Parti. 2012. Fluoroquinolone resistance in Neisseria gonorrhoeae: Fitness cost or benefit? J. Infect. Dis. 205 (12): 1775-1777.
  5. S. Vidovic, G. Horsman, M. Liao, and J.R. Dillon. 2011. Influence of conserved and hypervariable genetic markers on genotyping circulating strains of Neisseria gonorrhoeae. PLoS ONE 6 (12): e28259.
  6. S. A. Havaei, S. Vidovic, N. Tahmineh, K. Mohammad, K. Mohsen, S. Starnino, and J.R. Dillon. 2011. Epidemic methicillin-susceptible Staphylococcus aureus lineages are the major cause of infections at an Iranian university hospital. J. Clin. Microbiol. 49 (11): 3390-3993.
  7. J.R. Dillon. 2011. Sustainable antimicrobial surveillance programs essential for controlling Neisseria gonorrhoeae superbug. Sex. Transm. Dis. 38 (10): 899-901.
  8. R. Parti, D. Biswas, M. Wang, M. Liao, and J.R. Dillon. 2011. A MinD mutant of enterohemorrhagic E. coli O157:H7 has reduced adherence to human epithelial cells.  Microb. Pathog. 51: 378-383.
  1. M. Unemo and J.R. Dillon. 2011. Review and recommendation of methods for typing Neisseria gonorrhoeae isolates and their implications for improved knowledge of gonococcal epidemiology, treatment and biology. Clin. Micro. Rev. 24(3): 447-458.
  2. R.P. Parti, D. Biswas, S. Helgeson, F.S. Michael, A. Cox, and J.R Dillon. 2011. Attenuated virulence of min operon mutants of Neisseria gonorrhoeae and their interactions with human urethral epithelial cells. Microb. Infect. 13: 545-554.
  3. M. Liao, W-M Gu, Y. Yang, and J.R. Dillon. 2011. Analysis of mutations in multiple loci of Neisseria gonorrhoeae isolates reveals effects of PIB, PBP2 and MtrR on reduced susceptibility to ceftriaxone. J. Antimicrob. Chemother. 66: 1016-1023.
  4. P. Cybulska, S.D. Thakur, B.C. Foster, I.M. Scott, R. Leduc, J.T. Arnason, and J.R. Dillon. 2011. Extracts of Canadian first nations medicinal plants, used as natural products, inhibit Neisseria gonorrhoeae isolates with different antibiotic resistance profiles. Sex. Transm. Dis. 38(7):667-671.
  1. Ghasriani H, Ducat T, Hart CT, Hafizi F, Chang N, Al-Baldawi A, Ayed SH, Lundström P, J.R. Dillon, Goto NK. 2010. Appropriation of the MinD protein-interaction motif by the dimeric interface of the bacterial cell division regulator MinE. Proc. Natl. Acad. Sci. USA. 107(43):18416-18421.
  2. P.S. Ruddock, M. Charlan, S. Ramirez, A. Lopez, G.H.N. Towers, J.T. Arnason, M. Liao, J.R. Dillon. 2010. Antimicrobial activity of Piper lanceaefolium and other Colombian medicinal plants against antibiotic susceptible and resistant strains of Neisseria gonorrhoeae. Pubmed: Sex Transm Dis. 38(2):82-88.
  3. M. Liao, S. Helgeson, W-M Gu, Y. Yang, A.M. Jolly and J.R. Dillon. 2009. Comparison of Neisseria gonorrhoeae Multiantigen Sequence Typing and porB sequence analysis for identification of N. gonorrhoeae isolates. J. Clin. Microbiol. 47:489-491.
  4. M.D. Rigden, C. Baier, S. Ramirez-Arcos, M. Liao, M. Wang and J.R. Dillon. 2008. Identification of the coiled-coil domains of Enterococcus faecalis DivIVA that mediate oligomerization and their importance for biological function. J. Biochem. 144:63-76.
  5. M. Liao, K. Bell, W-M Gu, Y. Yang, N.F. Eng, W. Fu, L. Wu, C-G Zhang, Y. Chen, A.M. Jolly, and J.R. Dillon. 2008. Clusters of circulating Neisseria gonorrhoeae strains and association with antimicrobial resistance in Shanghai. J. Antimicrob. Chemother. 61:478-487.
  6. V. Greco-Stewart, Ramirez-Arcos, M. Liao and J.R. Dillon. 2007. N-terminus determinants of MinC from Neisseria gonorrhoeae mediate interaction with FtsZ but do not affect interaction with MinD or homodimerization. Arch. Microbiol. 187:451-458.
  7. Yang Yang, Mingmin Liao, Wei-Ming Gu, Kelli Bell, Lei Wu, Nelson F. Eng, Chu-Guang Zhang, Yue Chen, Ann M. Jolly, and Jo-Anne R. Dillon. 2006. Antimicrobial susceptibility and molecular determinants of quinolone resistance in Neisseria gonorrhoeae isolates from Shanghai. J Antimicrobial Chemother 58: 868-872.
  8. Dennis Ramos, Thierry Ducat, Jenny Cheng, Nelson F. Eng, Jo-Anne R. Dillon and Natalie K Goto. 2006. Conformation of the cell division regulator MinE: evidence for interactions between the topological specificity and anti-MinCD domains. Biochem. 45(14):4593-4601.
  9. Eng, N.F., Szeto, J., Acharya, S., Tessier, D., and J.R. Dillon. 2006. The C-terminus of MinE from Neisseria gonorrhoeae acts as a topological specificity factor by modulating MinD activity in bacterial cell division. Res. Microbiol. 157(4):333-344.
  10. J.R. Dillon, Ruben, M., H. Li, Borthagaray, G., Marquez, C., Fiorito, S., Galarza, P., Portilla, J.L., Leon, L., Agudelo CI, Sanabria OM, Maldonado A, and Prabhakar P. 2006. Challenges in the control of gonorrhea in South America and the Caribbean: monitoring the development of resistance to anitibiotics. Sex. Trans. Dis. 33(2):87-95.
  11. M. Liao, P.S. Ruddock, A.S. Rizvi, S.H. Hall, F.S. French, and J.R. Dillon. 2005. A cationic peptide of the male reproductive tract, HE2α, displays potent antimicrobial activity against Neisseria gonorrhoeae, Staphylococcus aureus, and Enterococcus faecalis.
    J Antimicrobial Chemother. 56, 957-961.
  12. Ruddock, P.S., M. Liao, B. Foster, L. Lawson, J.T. Arnason and J.R. Dillon. 2005. Garlic natural health products exhibit variable constituent levels and antimicrobial activity against Neisseria gonorrhoeae, Staphylococcus aureus and Enterococcus faecalis. Phytother Res 19:327-334.
  13. Szeto, J., N.F. Eng, S. Archarya, M. Rigden, and J.R. Dillon. 2005. A conserved polar region in the cell division site determinant MinD is required for responding to MinE-induced oscillation but not for localization within coiled arrays. Res Microbiol. 156: 17-29.
  14. Ramirez-Arcos, S., M. Liao, S. Marthaler, M. Rigden, and J.R. Dillon. 2005. Enterococcus faecalis divIVA: an essential gene involved in cell division, cell growth, and chromosome segregation. Microbiolog 151: 1381-1393.
  15. Szeto, J., Acharya, S., Eng, N.F., and J.R. Dillon. 2004. The N-terminus of MinD contains determinants which affect its dynamic localization and enzymatic activity. J. Bacteriol. 186: 7175-7185.
  16. Ramirez-Arcos, S., V. Greco, H. Douglas, D. Tessier, D. Fan, J. Wang, J. Szeto and J.R. Dillon. 2004. Conserved glycines in the C-terminus of MinC mediate protein are implicated in their functionality as a cell division inhibitors. J. Bacteriol. 186: 2841-2855.
  17. Greco, V., L.-K. Ng, R Catana, H. Li, and J.R. Dillon. 2003. Molecular epidemiology of tetracycline resistant Neisseria gonorrhoeae (TRNG) in Canada: temporal and geographical trends and prevalence from 1986 to 1997. Microb. Drug Resist. 9:353-360
  18. Sosa, J., S. Ramirez-Arcos, M. Ruben, H. Li, R. Llanes, A. Llop, and J.R. Dillon. 2003. High percentages of resistance to tetracycline and penicillin and reduced susceptibility to azithromycin characterize the majority of strain types of Neisseria gonorrhoeae isolates in Cuba, 1995-1998.Sex. Trans. Dis. 30:443-448.
  19. Ramirez-Arcos, S., J. Szeto, J.R. Dillon and W. Margolin. 2002. Conservation of dynamic localization among MinD and MinE orthologs: Oscillation of Neisseria gonorrhoeae proteins in Escherichia coli. Mol. Microbiol. 46: 493-504.
  20. Márquez, C., J.R. Dillon, V. Rodriguez and G. Borthagaray. 2002. Detection of a novel tetM determinant in tetracycline-resistant Neisseria gonorrhoeae from Uruguay, 1996-1999. Sex. Trans. Dis. 29:792-797.
  21. Hill, S.A., D. S. Samuels, C. Nielsen, S.W. Knight, F. Pagotto and J.R. Dillon. 2002. Integration host factor interactions with Neisseria gene sequences: Correlation between predicted binding sites and in vitro binding of Neisseria-derived IHF Protein. Molec. Cell. Probes. 16:153-158.
  22. Ramirez-Arcos, S., H. Salimnia, I. Bergevin, M. Paradis, J.R. Dillon. 2001. Expression of Neisseria gonorrhoeae cell division genes ftsZ, ftsE and mindD is influenced by environmental conditions. Res. Microbial. 152:781-791
  23. Szeto, J., S. Ramirez-Arcos, C. Raymond, L.D. Hicks, C.M. Kay, and J.R. Dillon. 2001. Gonoccoccal MinD affects cell division in Neisseria gonorrhoeae and Escherichia coli and exhibits a novel self interaction. J. Bacteriol. 183:6253-6264.
  24. Pagotto, F., and J.R. Dillon. 2001. Multiple origins and replication proteins influence the biological properties of β-lactamase-producing plasmids from Neisseria gonorrhoeae. J. Bacteriol. 183:5472-5481.
  25. Dillon, J.R., H. Li, J. Sealy, M. Ruben, The Caribbean Gonococcal Antimicrobial Susceptibility Program (GASP) Network and P. Prabhakar. 2001. Antimicrobial susceptibility of Neisseria gonorrhoeae isolates from three Caribbean countries - Trinidad, Guyana and St. Vincent. Sex. Trans. Dis. 28:508-514.
  26. Dillon, J.R., J-P.A. Rubabaza, A. Schwartz Benzaken, J.C.G. Sardinha, H. Li, M.G. Campos Bandeira, and E. Dos Santos Fernando Filho. 2001. Reduced susceptibility to azithromycin and high percentages of penicillin and tetracycline resistance in Neisseria gonorrhoeae isolates from Manaus, Brazil. Sex. Trans. Dis. 28:521-526.
  27. Ramirez-Arcos, S., T.J. Beveridge, J. Szeto, C. Victor, F. Francis and J.R. Dillon. 2001. Deletion of the cell division inhibitor MinC results in lysis of Neisseria gonorrhoeae. Microbiol. 147:225-237.
  28. Bernatchez, S., F. Francis, H. Salimnia, T.J. Beveridge, H. Li and J.R. Dillon. 2000. Genomic, transcriptional and phenotypic analysis of ftsE and ftsX of Neisseria gonorrhoeae. DNA Res. 7:75-81.
  29. Francis, F., S. Ramirez-Arcos, H. Salimnia, C. Victor and J.R. Dillon. 2000. Organization and transcription of the division cell wall (dcw) cluster in Neisseria gonorrhoeae. Gene 251:141-151.
  30. Pagotto, F., H. Salimnia, P.A. Totten and J.R. Dillon. 2000. Stable shuttle vectors for Neisseria gonorrhoeae, Haemophilus spp. and other bacteria based on a single origin of replication. Gene 244:13-19
  31. Pagotto, F., T. Aman, L.-K. Ng, K.-H. Yeung, M. Brett and J.R. Dillon. 2000. Sequence analysis of the family of penicillinase-producing plasmids of Neisseria gonorrhoeae based on DNA sequencing. Plasmid 43:24-34.
  32. Salimnia, H., A. Radia, S. Bernatchez, T.J. Beveridge and J.R. Dillon. 2000. Characterization of the ftsZ cell division gene of Neisseria gonorrhoeae: expression in Escherichia coli and N. gonorrhoeae. Arch. Microbiol. 173:10-20.
  33. Dillon, J.R. and F. Pagotto. 1999. Importance of drug resistance in gonococci: From mechanisms to monitoring. Curr. Op. Infec. Dis. 12:35-40.




Former graduate students and PDFs/research associates (40 former honours students not listed):


PDFs/Research associates:

2010 February - R. Parti, Research Manager

2010 - 2012- S. Starnino, PDF

2004-2011 M. Liao, Research Manager

2010 - 2011- A. Havaei, Visiting Scientist

2009 - 2012 - S. Vidovic, Postdoctoral Fellow

2006-2009 - D. Biswas, Research Associate

2008 Oct-Dec - M. Haakensen, Postdoctoral Fellow

2006-2008 - M. Horbay, Postdoctoral Fellow

2003- M. Liao, Research Associate

2003-2004 T. Morozova, Research Associate

2000-2004 M. Ruben, Research Associate (part-time)

1998-2003 S. Ramirez, Postdoctoral Fellow and Research Associate

1997-2000 H. Salimnia, Postdoctoral Fellow

1997 S. Banerjee, Research Associate

1993 C. LaFerriere, Visiting Fellow, Canadian Government Laboratory(co-supervision)

1990-1991 V. Thatte, Visiting Postdoctoral Fellow, Canadian Government Laboratory (co-supervision)

1990-1991 B. Blais, Visiting Fellow, Canadian Government Laboratory

1990 C. Hutnick, NSERC Postdoctoral Fellow (summer)

1987-1988 L.-K. Ng, MRC Postdoctoral Fellow

1985-1987 R. Roy, Visiting Fellow, Canadian Government Laboratory

Ph.D. students:

Mingmin Liao. (Ph.D.), Molecular epidemiology and molecular mechanisms of antimicrobial resistance in Neisseria gonorrhoeae in China: Implications for disease control. Defended June 3, 2011. Dept Microbiology & Immunology, University of Saskatchewan, Jan 2007-Jun 2011.

Yan Li. (Ph.D.), Role of FtsA in cell division in Neisseria gonorrhoeae. Defended April 19, 2011. University of Saskatchewan, Dept of Biology. Sep 2006 - May 2011.

Nelson F. Eng (Ph.D.), A MinE study: Functional characterization of the cell division protein MinE from the Gram-negative coccus Neisseria gonorrhoeae. September 2002-October 2007.

Jason Szeto (Ph.D.), The role of MinD in Neisseria gonorrhoeae cell division, Completed in 2004

Franco Pagotto (Ph.D.), Genetic and molecular characterization of origins of replication from b-lactamase-producing plasmid of Neisseria gonorrhoeae, completed in 2001

Stephane Bernatchez (Ph.D.), Molecular cloning and characterization of the ftsEX genes of Neisseria gonorrhoeae CH811 encoding a putative ABC transporter and identification of their flanking genes,completed in 1998

James Ng (Ph.D.), Characterization of Peptostreptococcus species by Aminopeptidase profiles and genotyping methods, completed in 1996

Fiona S. Lawson, (Ph.D.), Carbamoylphosphate synthetase (CPS) genes of Neisseria gonorrhoeae and other Neisseria species: Novel gene organization, variable intergenic sequences, characterization of naturally occurring mutants, and evolution of CPS genes, completed in 1996

França;ois J. Picard, (Ph.D.), Genetics of arginine and proline biosynthesis in Neisseria gonorrhoeae, completed in 1991

Kwok-Him Yeung (Ph.D.), Genetic analysis and molecular characterization of the naturally-occuring penicillinase-producing plasmids in Neisseria gonorrhoeae, completed in 1989

M.Sc. students:

Guanqun Liu. (M.Sc.), Modulation of apoptosis in human urethral epithelial cells by wild-type neisseria gonorrhoeae and its isogenic MinD mutant strain. Defended November 5, 2012. Dept of Biology, University of Saskatchewan, Sep 2010-Nov 2012.

Cherise Hedlin (M.Sc.), The Essentiality of DivIVAEf Oligomerization for Proper Cell Division in Enterococcus faecalis and Interaction with a Novel Cell Division Protein. Sept. 2006-May 2009.

Sudeep Acharya (M.Sc.), (Co-supervised with N. Goto). Biochemical structural and functional analysis of the cell division site determinant MinDNg: To divide or not to divide. September 2003-May 2006.

Patrick Ruddock (M.Sc.), Plant derived compounds with antimicrobial activity towards Neisseria gonorrhoeae. completed in 2005.

Susan Marthaler (M.Sc.), Uncoiling the mysteries of DivIVAEf: The biological functioning of the enterococcus faecalis cell development protein. completed in 2005.

Marc Rigden (M.Sc.), Structural and biochemical analysis of DivIVA from Enterococcus faecalis,completed in 2005.

Valerie Greco (M.Sc.), Functional analysis of the role of conserved Glycine residues and N-terminus motifs in the cell division inhibitor MinC from Neisseria gonorrhoeae, completed in 2004

Finola Francis (M.Sc.), Transcriptional analysis of cell division genes in Neisseria gonorrhoeae, completed in 1998

Avni Radia (M.Sc.), Molecular characterization of the cell division gene ftsZ in Neisseria gonorrhoeae, completed in 1997

Abu Tholib Aman (M.Sc.), Structural studies of the β-Lactamase-producing plasmids of Neisseria gonorrhoeae, completed in 1994

Hui Li (M.Sc.), Evaluation of molecular typing methods to discriminate between isolates of Neisseria gonorrhoeae: Restriction endonuclease analysis, ribotyping and pulsed field gel electrophoresis, completed in 1993

Benoit R. Gauthier (M.Sc.), Development of a novel shuttle system for the transfer of Gonococcal genes between Escherichia coli and Neisseria gonorrhoeae, completed in 1990

Kimberly Hannah (M.Sc.), Physical and genetic analysis of a conjugative plasmid of Neisseria gonorrhoeae and its role in the evolution of gonococcal strains, completed in 1988

[an error occurred while processing this directive]Last Modified:Monday, 23 September, 2013.