TY - JOUR A1 - Schellenberg, Johannes A1 - Reichert, Jessica A1 - Hardt, Martin A1 - Klingelhöfer, Ines A1 - Morlock, Gertrud A1 - Schubert, Patrick A1 - Bižić, Mina A1 - Grossart, Hans-Peter A1 - Kämpfer, Peter A1 - Wilke, Thomas A1 - Glaeser, Stefanie P. T1 - The bacterial microbiome of the long-term aquarium cultured high-microbial abundance sponge Haliclona cnidata BT - sustained bioactivity despite community shifts under detrimental conditions JF - Frontiers in Marine Science N2 - Marine sponges host highly diverse but specific bacterial communities that provide essential functions for the sponge holobiont, including antimicrobial defense. Here, we characterized the bacterial microbiome of the marine sponge Haliclona cnidata that has been in culture in an artificial marine aquarium system. We tested the hypotheses (1) that the long-term aquarium cultured sponge H. cnidata is tightly associated with a typical sponge bacterial microbiota and (2) that the symbiotic Bacteria sustain bioactivity under harmful environmental conditions to facilitate holobiont survival by preventing pathogen invasion. Microscopic and phylogenetic analyses of the bacterial microbiota revealed that H. cnidata represents a high microbial abundance (HMA) sponge with a temporally stable bacterial community that significantly shifts with changing aquarium conditions. A 4-week incubation experiment was performed in small closed aquarium systems with antibiotic and/or light exclusion treatments to reduce the total bacterial and photosynthetically active sponge-associated microbiota to a treatment-specific resilient community. While the holobiont was severely affected by the experimental treatment (i.e., bleaching of the sponge, reduced bacterial abundance, shifted bacterial community composition), the biological defense and bacterial community interactions (i.e., quorum sensing activity) remained intact. 16S rRNA gene amplicon sequencing revealed a resilient community of 105 bacterial taxa, which remained in the treated sponges. These 105 taxa accounted for a relative abundance of 72-83% of the bacterial sponge microbiota of non-treated sponge fragments that have been cultured under the same conditions. We conclude that a sponge-specific resilient community stays biologically active under harmful environmental conditions, facilitating the resilience of the holobiont. In H. cnidata, bacteria are located in bacteriocytes, which may have contributed to the observed phenomenon. KW - HMA sponge KW - bacterial symbionts KW - holobiont KW - antimicrobial defense KW - quorum sensing KW - bacteriocytes Y1 - 2020 U6 - https://doi.org/10.3389/fmars.2020.00266 SN - 2296-7745 VL - 7 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Fasching, Christina A1 - Akotoye, Christian A1 - Bižić, Mina A1 - Fonvielle, Jeremy Andre A1 - Ionescu, Danny A1 - Mathavarajah, Sabateeshan A1 - Zoccarato, Luca A1 - Walsh, David A. A1 - Grossart, Hans-Peter A1 - Xenopoulos, Marguerite A. T1 - Linking stream microbial community functional genes to dissolved organic matter and inorganic nutrients JF - Limnology and oceanography N2 - There is now increasing evidence for the importance of microbial regulation of biogeochemical cycling in streams. Resource availability shapes microbial community structure, but less is known about how landscape-mediated availability of nutrients and carbon can control microbial functions in streams. Using comparative metagenomics, we examined the relationship between microbial functional genes and composition of dissolved organic matter (DOM), nutrients, and suspended microbial communities in 11 streams, divided into three groups based on the predominant land cover category (agriculture, forested, or wetland). Using weighted gene co-occurrence network analysis, we identified clusters of functions related to DOM composition, agricultural land use, and/or wetland and forest land cover. Wetland-dominated streams were characterized by functions related to nitrogen metabolism and processing of aromatic carbon compounds, with strong positive correlations with dissolved organic carbon concentration and DOM aromaticity. Forested streams were characterized by metabolic functions related to monomer uptake and carbohydrates, such as mannose and fructose metabolism. In agricultural streams, microbial functions were correlated with more labile, protein-like DOM, PO4, and NO3, likely reflecting functional adaptation to labile DOM and higher nutrient concentrations. Distinct changes in the functional composition and loss of functional diversity of microorganisms became evident when comparing natural to agricultural catchments. Although all streams showed signs of functional redundancy, loss of species richness per function in agricultural catchments suggests that microbial functions in natural catchments may be more resilient to disturbance. Our results provide new insight into microbial community functions involved in nutrient and carbon biogeochemical cycles and their dependence on specific environmental settings. Y1 - 2019 U6 - https://doi.org/10.1002/lno.11356 SN - 0024-3590 SN - 1939-5590 VL - 65 SP - S71 EP - S87 PB - Wiley CY - Hoboken ER -