ALBERT

Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bent, S. M., Miller, C. A., Sharp, K. H., Hansel, C. M., & Apprill, A. Differential patterns of microbiota recovery in symbiotic and aposymbiotic corals following antibiotic disturbance. Msystems, 6(2), (2021): e01086-20, https://doi.org/10.1128/mSystems.01086-20.

Description: Microbial relationships are critical to coral health, and changes in microbiomes are often exhibited following environmental disturbance. However, the dynamics of coral-microbial composition and external factors that govern coral microbiome assembly and response to disturbance remain largely uncharacterized. Here, we investigated how antibiotic-induced disturbance affects the coral mucus microbiota in the facultatively symbiotic temperate coral Astrangia poculata, which occurs naturally with high (symbiotic) or low (aposymbiotic) densities of the endosymbiotic dinoflagellate Breviolum psygmophilum. We also explored how differences in the mucus microbiome of natural and disturbed A. poculata colonies affected levels of extracellular superoxide, a reactive oxygen species thought to have both beneficial and detrimental effects on coral health. Using a bacterial and archaeal small-subunit (SSU) rRNA gene sequencing approach, we found that antibiotic exposure significantly altered the composition of the mucus microbiota but that it did not influence superoxide levels, suggesting that superoxide production in A. poculata is not influenced by the mucus microbiota. In antibiotic-treated A. poculata exposed to ambient seawater, mucus microbiota recovered to its initial state within 2 weeks following exposure, and six bacterial taxa played a prominent role in this reassembly. Microbial composition among symbiotic colonies was more similar throughout the 2-week recovery period than that among aposymbiotic colonies, whose microbiota exhibited significantly more interindividual variability after antibiotic treatment and during recovery. This work suggests that the A. poculata mucus microbiome can rapidly reestablish itself and that the presence of B. psygmophilum, perhaps by supplying nutrients, photosynthate, or other signaling molecules, exerts influence on this process. IMPORTANCE Corals are animals whose health is often maintained by symbiotic microalgae and other microorganisms, yet they are highly susceptible to environmental-related disturbances. Here, we used a known disruptor, antibiotics, to understand how the coral mucus microbial community reassembles itself following disturbance. We show that the Astrangia poculata microbiome can recover from this disturbance and that individuals with algal symbionts reestablish their microbiomes in a more consistent manner compared to corals lacking symbionts. This work is important because it suggests that this coral may be able to recover its mucus microbiome following disturbance, it identifies specific microbes that may be important to reassembly, and it demonstrates that algal symbionts may play a previously undocumented role in microbial recovery and resilience to environmental change.

Description: Funding from a National Science Foundation Research Experiences for Undergraduates grant (NSF REU OCE-1659463) to WHOI supported S.B.’s time at WHOI as a Summer Student Fellow. A Dalio Explore Award and NSF OCE-1736288 to A.A. and NSF OCE-1355720 to C.M.H. further supported this work. K.S. was supported in part by the INBRE-NIGMS of the NIH grant P20GM103430.

Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Zeiner, C. A., Purvine, S. O., Zink, E., Wu, S., Pasa-Tolic, L., Chaput, D. L., Santelli, C. M., & Hansel, C. M. Mechanisms of manganese(II) oxidation by filamentous ascomycete fungi vary with species and time as a function of secretome composition. Frontiers in Microbiology, 12, (2021): 610497, https://doi.org/10.3389/fmicb.2021.610497.

Description: Manganese (Mn) oxides are among the strongest oxidants and sorbents in the environment, and Mn(II) oxidation to Mn(III/IV) (hydr)oxides includes both abiotic and microbially-mediated processes. While white-rot Basidiomycete fungi oxidize Mn(II) using laccases and manganese peroxidases in association with lignocellulose degradation, the mechanisms by which filamentous Ascomycete fungi oxidize Mn(II) and a physiological role for Mn(II) oxidation in these organisms remain poorly understood. Here we use a combination of chemical and in-gel assays and bulk mass spectrometry to demonstrate secretome-based Mn(II) oxidation in three phylogenetically diverse Ascomycetes that is mechanistically distinct from hyphal-associated Mn(II) oxidation on solid substrates. We show that Mn(II) oxidative capacity of these fungi is dictated by species-specific secreted enzymes and varies with secretome age, and we reveal the presence of both Cu-based and FAD-based Mn(II) oxidation mechanisms in all 3 species, demonstrating mechanistic redundancy. Specifically, we identify candidate Mn(II)-oxidizing enzymes as tyrosinase and glyoxal oxidase in Stagonospora sp. SRC1lsM3a, bilirubin oxidase in Stagonospora sp. and Paraconiothyrium sporulosum AP3s5-JAC2a, and GMC oxidoreductase in all 3 species, including Pyrenochaeta sp. DS3sAY3a. The diversity of the candidate Mn(II)-oxidizing enzymes identified in this study suggests that the ability of fungal secretomes to oxidize Mn(II) may be more widespread than previously thought.

Description: This work was supported by the National Science Foundation, grant numbers EAR-1249489 and CBET-1336496, both awarded to CH, by a JGI-EMSL Collaborative Science Initiative grant (proposal number 48100) awarded to CH and CS, and by the University of St. Thomas. Personal support for CZ was also provided by Harvard University and by a Ford Foundation Predoctoral Fellowship administered by the National Academies. A portion of this research was performed under the Facilities Integrating Collaborations for User Science (FICUS) program and used resources at the DOE Joint Genome Institute and the Environmental Molecular Sciences Laboratory (grid.436923.9), which are DOE Office of Science User Facilities. Both facilities are sponsored by the Biological and Environmental Research Program and operated under Contract Nos. DE-AC02-05CH11231 (JGI) and DE-AC05-76RL01830 (EMSL). Part of this research was performed at the Bauer Core Facility of the FAS Center for Systems Biology at Harvard University. A portion of the bioinformatics analysis was performed at Harvard’s FAS Research Computing facility.

Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Farfan, G. A., Apprill, A., Cohen, A., DeCarlo, T. M., Post, J. E., Waller, R. G., & Hansel, C. M. Crystallographic and chemical signatures in coral skeletal aragonite. Coral Reefs. (2121), https://doi.org/10.1007/s00338-021-02198-4.

Description: Corals nucleate and grow aragonite crystals, organizing them into intricate skeletal structures that ultimately build the world’s coral reefs. Crystallography and chemistry have profound influence on the material properties of these skeletal building blocks, yet gaps remain in our knowledge about coral aragonite on the atomic scale. Across a broad diversity of shallow-water and deep-sea scleractinian corals from vastly different environments, coral aragonites are remarkably similar to one another, confirming that corals exert control on the carbonate chemistry of the calcifying space relative to the surrounding seawater. Nuances in coral aragonite structures relate most closely to trace element chemistry and aragonite saturation state, suggesting the primary controls on aragonite structure are ionic strength and trace element chemistry, with growth rate playing a secondary role. We also show how coral aragonites are crystallographically indistinguishable from synthetic abiogenic aragonite analogs precipitated from seawater under conditions mimicking coral calcifying fluid. In contrast, coral aragonites are distinct from geologically formed aragonites, a synthetic aragonite precipitated from a freshwater solution, and mollusk aragonites. Crystallographic signatures have future applications in understanding the material properties of coral aragonite and predicting the persistence of coral reefs in a rapidly changing ocean.

Description: This project was funded by the Mineralogical Society of America Edward H. Kraus Crystallographic Research Fund and the WHOI Ocean Ventures Fund. G. Farfan was supported by a National Science Foundation Graduate Research Fellowship Grant No. 1122374 and a Ford Foundation Dissertation Fellowship. Sample collections from R. Waller were funded under NSF Grant Numbers 1245766, 1127582 and NOAA Ocean Exploration Deep Atlantic Stepping Stones. The authors thank Erik Cordes for the samples collected from the Gulf of Mexico, which were supported by NSF BIO-OCE Grant # 1220478. STZC collections from A. Apprill were funded by a Dalio Foundation (now ‘OceanX’) and a KAUST-WHOI Special Academic Partnership Funding Reserve with Christian Voolstra. Research and coral collections in Cuba were conducted under the LH112 AN (25) 2015 license granted by the Cuban Center for Inspection and Environmental Control with the assistance of Patricia Gonzalez and Michael Armenteros. Corals from Western Australia were collected under license number SF009558 obtained by M. McCulloch, and from the Maldives Ministry of Fisheries and Agriculture with collection permits (No. (OTHR)30-D/INDIV/2013/359). Matthew Neave assisted with the collections.