Microbial Interaction and Bioactive Discovery

The broad aim of our research is to gain a better understanding of the interactions between marine microbes and their eukaryotic hosts, from both an ecological and cellular/mechanistic perspective.

Little is known about the phylogenetic composition of many host-associated microbial populations and the functional roles of their members. Studies such as these are significant on a number of levels. For example, understanding the diversity and function of eukaryotic-associated microbes can add to our understanding of disease, provide insight to the rich global biodiversity, and lead to the discovery of new and improved processes and products. Current projects include (but are not limited to):

1.  Discovery of novel bioactive compounds from marine host-associated bacteria.
We have used a blend of bacterial culturing and culture-independent approaches to identify new metabolites (and in some cases the genes that lead to their expression) with antibacterial, antifungal, antidiatom and antinematode activities. This work has been done in collaboration with Dr. Torsten Thomas and Dr. Tilmann Harder.

2. Characterisation of host colonisation and virulence gene homologs in selected marine bacteria.
Analysis of recently sequenced marine bacterial genomes, including that of our model host-associated bacterium Pseudoalteromonas tunicata, has revealed an abundance of “virulence”-like genes. To study the role of these genes and their products we are currently constructing specific null mutants in selected virulence genes and will assess the resulting strains with respect to colonisation and environmental stress adaptation.

3. Effect of environmental stress on the phenotypic variation of biofilm dispersal cell populations in marine host-associated bacteria.
An important stage in the biofilm lifecycle is the cell dispersal event, in which often stable phenotypic variants are released. In this project we are investigating the impact of environmental stress conditions, such as the presence of a competitor on the extent and type of variation present. The model systems we are currently using include the co-occurring algal host-associated bacteria Pseudoalteromonas tunicata and Phaeobacter gallaeciensis. This work has been done in collaboration with Professor Staffan Kjelleberg.

BABS personnel responsible for these projects:

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