Sticking Together: How food-contaminating bacteria form multicellular communities on surfaces

PhD defence, Friday, 24 February 2017. Mira Ursula Okshevsky.

2017.02.24 | Steffi Hjerrild Iversen

Mira Ursula Okshevsky

Listeria bacteria (red) cluster around clumps of DNA (green). This sticky DNA helps to hold Listeria biofilms together, making them vulnerable to removal by DNA-degrading enzymes.

During her PhD studies, Mira Ursula Okshevsky investigated how food-borne bacteria are able to form multicellular communities called biofilms. Biofilms form on food and food processing equipment, resulting in food spoilage and, given the wrong kind of bacteria, food poisoning. Mira Ursula Okshevsky has studied how bacteria use DNA on the outside of their cells to hold a biofilm together. Her research has determined that under food-processing conditions, biofilms formed by Listeria monocytogenes (causative agent of the food-borne illness listeriosis) can be completely removed by an enzyme that targets DNA. This research has exciting implications for the control of biofilms in the food industry.

Mira Ursula Okshevsky has additionally investigated which genes the common dairy-contaminant Bacillus cereus uses to form a biofilm, advancing our knowledge of the fundamental molecular principles regulating biofilm formation.

The PhD degree was completed at the Interdisciplinary Nanoscience Center (iNANO), Science and Technology, Aarhus University.

This résumé was prepared by the PhD student.

Time: Friday, 24 February 2017 at 10.15
Place: Building 1523, room 318, the Lecture Theatre, Department of Physics and Astronomy, Ny Munkegade 120, Aarhus University, 8000 Aarhus C.
Title of dissertation: Mechanisms of Biofilm Formation by Food-borne Bacteria
Contact information: Mira Ursula Okshevsky, e-mail:, tel.: +45 2253 0029
Members of the assessment committee:
Dr. Ákos T. Kovács, Friedrich Schiller University Jena, Germany
Professor Lone Gram, Department of Biotechnology and Biomedicine, Technical University of Denmark
Associate Professor Duncan Sutherland (chair), iNANO, Aarhus University

Main supervisor:
Associate Professor Rikke Louise Meyer, iNANO and Department of Bioscience, Aarhus University
Professor Andreas Schramm, Section for Microbiology, Department of Bioscience, Aarhus University
Language: The PhD dissertation will be defended in English

The defence is public.
The dissertation is available for reading at the Graduate School of Science and Technology/GSST, Ny Munkegade 120, building 1520, rooms 128-134, 8000 Aarhus C.

PhD defence
Comments on content: 
Revised 23.02.2018