Waleed (right) with examiners Thuy Do (centre left) and Kevin Waldron (centre right), and supervisor Nick Jakubovics (left).

Congratulations to Waleed Mohammed, who passed his PhD today (subject to the usual minor corrections)! Waleed has worked incredibly hard over the last 4-5 years and fully deserves his PhD.

His project focussed on understanding the ways that bacterial cells of different species interact with one another. In the laboratory, certain oral bacteria will specifically bind to one another, forming large aggregates. We think that this type of cell-cell binding drives the formation of dental plaque on tooth surfaces.

Waleed developed some neat new techniques for imaging coaggregates and used them to study the dynamics of coaggregate formation in vitro. With our collaborators in the School of Computing, we used this as a case study for their new ‘Simbiotics’ platform, which aims to bring together models for lots of different biological processes in one platform. This was published in ACS Synthetic Biology.

Later, Waleed used Molecular genetics to uncover a new role of the secreted protease Challisin in cell-cell sensing between the oral bacteria Streptococcus gordonii and Actinomyces oris (paper in FEMS Microbiology Ecology). Finally, working with our collaborators in Malaysia (now in China), Waleed used RNASeq to detect changes in gene expression in S. gordonii and Fusobacterium nucleatum following coaggregation.

Overall, Waleed covered a huge amount of ground in his PhD. He has collaborated with people in Newcastle, Malaysia, and more recently our lab’s long-term collaborator Alex Rickard, University of Michigan. This is fantastic preparation for what I am sure will be a very successful career. Well done Waleed!