Bacteriocins to help brassicas: Robyn’s placement report

Our final placement report is from Robyn Babb. Robyn is a PhD student with the Xanthomonas Threats project. She visited the University of Strathclyde and the University of Glasgow. Robyn’s placement was made possible thanks to additional funding from UKRI to enable some of our researchers to go on placements to different work environments to learn skills and build relationships. here is Robyn’s placement report.

I am Robyn Babb, working at the University of Warwick on a Xanthomonas Threats sub-project with Shannon Greer, Murray Grant, and Megan Lewis. I am investigating the activity of bacteriocins (bacterial proteins with antimicrobial activity) on different Xanthomonas spp. We are investigating whether these can be used as biological control for disease caused by Xanthomonas, such as black rot in Brassica spp. Using a large genomic screen we have identified a range of bacteriocins predicted to be active against Xanthomonas spp. We are now focused on optimising the expression of these bacteriocins in different E. coli cell lines and purifying them using His-tag affinity chromatography.

My two-week-collaboration with the University of Strathclyde and the University of Glasgow was a great opportunity to learn about how to purify bacteriocins on a larger scale, and importantly, how to extract and solubilise bacteriocins from inclusion bodies. It was also an excellent chance for me to learn more about what steps this project could take in the future, such as re-cloning the bacteriocin with structural changes to avoid inhibition by immunity proteins. I also had the opportunity to test the activity of different bacteriocins on a range of different Xanthomonas spp.

During my placement I was able to work at both Glasgow universities (Glasgow and Strathclyde) which have complementary areas of expertise. It was really helpful to learn scale-up processes, enabling expression in litres rather than 50ml cultures! I also learnt about different buffers which are particularly useful for purifying bacteriocins. It was very exciting to be able to use preparative chromatography on an AKTA Purifier in Strathclyde. This allows protein purification on a much larger scale than we were able to achieve at Warwick.

Critically, this placement allowed me to troubleshoot steps in my existing methods which may have inactivated some of the proteins that were previously expressed. These issues might include problems cloning and expression media. It was great to be able to gain such insights from groups who are considered experts in their field. I also had an amazing time sight-seeing in Glasgow. Overall, my two-week placement was both delightful and professionally informative. I would especially like to give a massive thank you to everyone who helped me at the Universities of Glasgow and Strathclyde from Dan Walker’s and Joel Milner’s labs. I would also like to thank the Bacterial Plant Diseases Programme as well as the funding bodies for this amazing opportunity.