Current research activities
Several ongoing projects concern the microbial ecology of the termite gut and the metabolic capacities of the microorganisms colonizing this habitat. Projects focusing on the bacterial symbionts of termite gut flagellates (the majority of the prokaryotes in the hindgut of lower, wood-feeding termites) deal with the putative roles of particular symbionts in nitrogen metabolism and use cultivation-independent metagenomic approaches. Since many bacterial lineages are shared among a wide range of termites and cockroaches, we are using high-throughput sequencing techniques to refine our understanding of the structure and evolution of the gut microbial community in cockroaches and termites and to differentiate between mechanisms of cospeciation and habitat selection.
Methanogenesis is of particular relevance in higher termites, and the archaeal communities in the different gut regions are astonishingly diverse (Brune, 2010b). We have enriched a member of a novel, deep-branching lineage of methanogenic archaea that is particularly common in soil-feeding species; we are sequencing the genome and characterizing the physiology of this archaeon. Moreover, we want to identify the drivers of methanogenic community structure in the highly compartmented hindgut, such as the availability of and competition for methanogenic substrates, and differences in adaptation to oxidative stress and other factors imposed by the environment.
In a project affiliated with the Center for Synthetic Microbiology at the Philipps-Universität Marburg, we have successfully established a new research direction using germ-free cockroaches as a model system for gnotobiotic studies. Preliminary results indicated that germ-free larvae develop poorly but are rescued by infection with conventional or foreign gut microbiota. We are presently constructing synthetic gut microbial communities from pure cultures of gut bacteria representing different microbial guilds. Future work will include the experimental testing of ecological principles and—in the long run—the study of potential host–microbe interactions.