@article {LacknerE347, author = {Lackner, Gerald and Peters, Eike Edzard and Helfrich, Eric J. N. and Piel, J{\"o}rn}, title = {Insights into the lifestyle of uncultured bacterial natural product factories associated with marine sponges}, volume = {114}, number = {3}, pages = {E347--E356}, year = {2017}, doi = {10.1073/pnas.1616234114}, publisher = {National Academy of Sciences}, abstract = {The candidate genus {\textquotedblleft}Candidatus Entotheonella{\textquotedblright} belongs to a recently proposed bacterial candidate phylum with largely unknown properties due to the lack of cultivated members. Among the few known biological properties is an association of Ca. Entotheonella with marine sponges and an extraordinarily rich genomic potential for bioactive natural products with unique structures and unprecedented biosynthetic enzymology. Increasing evidence suggests that Ca. Entotheonella are widespread key producers of sponge natural products with a chemical richness comparable to soil actinomycetes. Given the unusual biology and exceptional pharmacological potential of Ca. Entotheonella, the bioinformatic and functional insights into their lifestyle presented here provide diverse avenues for marine natural product research, biotechnology, and microbial ecology.The as-yet uncultured filamentous bacteria {\textquotedblleft}Candidatus Entotheonella factor{\textquotedblright} and {\textquotedblleft}Candidatus Entotheonella gemina{\textquotedblright} live associated with the marine sponge Theonella swinhoei Y, the source of numerous unusual bioactive natural products. Belonging to the proposed candidate phylum {\textquotedblleft}Tectomicrobia,{\textquotedblright} Candidatus Entotheonella members are only distantly related to any cultivated organism. The Ca. E. factor has been identified as the source of almost all polyketide and modified peptides families reported from the sponge host, and both Ca. Entotheonella phylotypes contain numerous additional genes for as-yet unknown metabolites. Here, we provide insights into the biology of these remarkable bacteria using genomic, (meta)proteomic, and chemical methods. The data suggest a metabolic model of Ca. Entotheonella as facultative anaerobic, organotrophic organisms with the ability to use methanol as an energy source. The symbionts appear to be auxotrophic for some vitamins, but have the potential to produce most amino acids as well as rare cofactors like coenzyme F420. The latter likely accounts for the strong autofluorescence of Ca. Entotheonella filaments. A large expansion of protein families involved in regulation and conversion of organic molecules indicates roles in host{\textendash}bacterial interaction. In addition, a massive overrepresentation of members of the luciferase-like monooxygenase superfamily points toward an important role of these proteins in Ca. Entotheonella. Furthermore, we performed mass spectrometric imaging combined with fluorescence in situ hybridization to localize Ca. Entotheonella and some of the bioactive natural products in the sponge tissue. These metabolic insights into a new candidate phylum offer hints on the targeted cultivation of the chemically most prolific microorganisms known from microbial dark matter.}, issn = {0027-8424}, URL = {https://www.pnas.org/content/114/3/E347}, eprint = {https://www.pnas.org/content/114/3/E347.full.pdf}, journal = {Proceedings of the National Academy of Sciences} }