Publications by authors named "Soeren Franzenburg"

The neritid snail Theodoxus fluviatilis is found across habitats differing in salinity, from shallow waters along the coast of the Baltic Sea to lakes throughout Europe. Living close to the water surface makes this species vulnerable to changes in salinity in their natural habitat, and the lack of a free-swimming larval stage limits this species' dispersal. Together, these factors have resulted in a patchy distribution of quite isolated populations differing in their salinity tolerances.

View Article and Find Full Text PDF

Background: Long-term selection experiments are a powerful tool to understand the genetic background of complex traits. The longest of such experiments has been conducted in the Research Institute for Farm Animal Biology (FBN), generating extreme mouse lines with increased fertility, body mass, protein mass and endurance. For >140 generations, these lines have been maintained alongside an unselected control line, representing a valuable resource for understanding the genetic basis of polygenic traits.

View Article and Find Full Text PDF

Upon injury, the homeostatic balance that ensures tissue function is disrupted. Wound-induced signaling triggers the recovery of tissue integrity and offers a context to understand the molecular mechanisms for restoring tissue homeostasis upon disturbances. Marine sessile animals are particularly vulnerable to chronic wounds caused by grazers that can compromise prey's health.

View Article and Find Full Text PDF

Most of the evidence that the gut microbiome of animals is functionally variable, with consequences for the health and fitness of the animal host, is based on laboratory studies, often using inbred animals under tightly controlled conditions. It is largely unknown whether these microbiome effects would be evident in outbred animal populations under natural conditions. In this study, we quantified the functional traits of the gut microbiota (metagenome) and host (gut transcriptome) and the taxonomic composition of the gut microorganisms (16S rRNA gene sequence) in natural populations of three mycophagous Drosophila species.

View Article and Find Full Text PDF

Despite evidence from laboratory experiments that perturbation of the gut microbiota affects many traits of the animal host, our understanding of the effect of variation in microbiota composition on animals in natural populations is very limited. The core purpose of this study on the fruit fly Drosophila melanogaster was to identify the impact of natural variation in the taxonomic composition of gut bacterial communities on host traits, with the gut transcriptome as a molecular index of microbiota-responsive host traits. Use of the gut transcriptome was validated by demonstrating significant transcriptional differences between the guts of laboratory flies colonized with bacteria and maintained under axenic conditions.

View Article and Find Full Text PDF

Most associations between animals and their gut microbiota are dynamic, involving sustained transfer of food-associated microbial cells into the gut and shedding of microorganisms into the external environment with feces, but the interacting effects of host and microbial factors on the composition of the internal and external microbial communities are poorly understood. This study on laboratory cultures of the fruit fly Drosophila melanogaster reared in continuous contact with their food revealed time-dependent changes of the microbial communities in the food that were strongly influenced by the presence and abundance of Drosophila. When germfree Drosophila eggs were aseptically added to nonsterile food, the microbiota in the food and flies converged to a composition dramatically different from that in fly-free food, showing that Drosophila has microbiota-independent effects on the food microbiota.

View Article and Find Full Text PDF