New Book: Cellular Dialogues in the Holobiont

Thomas Bosch recently edited the book “Cellular Dialogues in the Holobiont” together with Mike Hadfield from the University of Hawaii.

From the preface:

A dialogue that matters: microbe–host interactions in protists, plants, and animals.
Animal evolution appears intimately linked to the presence of microbes. A continuously increasing number of studies demonstrate that individuals from sponges to humans are not solitary, isolated entities, but consist of complex communities of many species that likely coevolved during a billion years of coexistence (McFall-Ngai et al., 2013). This progress is due in large part to the application of “metagenomic” methods: a series of experimental and computational approaches that allows a microbial community’s composition to be defined by DNA sequencing without having to culture its members. This work has yielded catalogues of microbial species, many previously unknown and belonging to all three domains of life, as well as lists of millions of microbial genes collectively known as a host’s microbiome. Research on host–microbe interactions has become an emerging cross-disciplinary field. Contrary to the classical view that microbes are primarily pathogenic and disease-causing, there is now a multitude of studies indicating that a host-specific microbiome provides functions related to metabolism, immunity, development, and environmental adaptation to its animal, plant, or fungal host. Similarly, microbes have been documented as important for environmental sensing, inducing colony formation and sexual reproduction in choanoflagellates, and contributing to developmental transitions and life history traits such as development pace and longevity. Similarly, the microbiome of plants impacts the phenotype and fitness of the plant host. It has become increasingly clear that animals, plants, and fungi evolved in a microbial world and that multicellular organisms rely on their associated microbes to function. Symbiosis appears as a general principle in eukaryotic evolution.

Interview mit Thomas Bosch zur Bedeutung des Mikrobioms in Zeiten von Covid-19

Yuuki Obata and Vassilis Pachnis from The Francis Crick Institute in London wrote a wonderful commentary in PNAS on our recent paper concluding that our studies in Hydra will be extremely valuable to understand the function and contributions of pacemaker cells (of mesenchymal or neural origin) to intestinal physiology and host defense against pathogens. Read the commentary here.

Video 1

Spontaneous body contractions of Hydra (65x acceleration). The spontaneous contractions are shrinkages of the body column that occur periodically in the absence of any exogenous stimuli.

Reference: Murillo-Rincon, A.P., Klimovich, A., Pemöller, E. et al. Spontaneous body contractions are modulated by the microbiome of Hydra. Sci Rep 7, 15937 (2017) doi:10.1038/s41598-017-16191-x

Video 3

In vivo imaging of neuronal activity in the hypostome of Hydra. The method of generating transgenic Hydra strains that express genetically encoded Ca2+-sensitive fluorescent proteins (GCaMP) in specific neuronal populations is established in the Bosch lab in Kiel. Here, the activity of the neuronal population N6 is induced by addition of reduced glutathione (GSH).

Credits: Christoph Giez / CAU Kiel

Video 5

Quantitative analysis of Hydra spontaneous contractile behavior. The animation explains the automatized video-recording of a freely behaving polyp and further analysis of the image sequence using a custom script to generate such metrics of the behavior as stretching and contractile capacity, contraction frequency and regularity.

Reference: Murillo-Rincon, A.P., Klimovich, A., Pemöller, E. et al. Spontaneous body contractions are modulated by the microbiome of Hydra. Sci Rep 7, 15937 (2017) doi:10.1038/s41598-017-16191-x