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Natural Product Reports Apr 2020Covering: up to the end of 2018Zoantharians, also improperly known as zoanthids or colonial anemones, are well known by aquarists because of their ease of use in aquaria... (Review)
Review
Covering: up to the end of 2018Zoantharians, also improperly known as zoanthids or colonial anemones, are well known by aquarists because of their ease of use in aquaria but also because of their splendid colours. However, high concentrations of the highly toxic palytoxin found in some species of zoantharians maintained in reef aquaria has raised some issues recently, unveiling at the same time a rather unknown chemical diversity hidden in these marine beauties. Herein, we report the structure of the metabolites described in all species of zoantharians up to the end of 2018 and their associated biological activities. As sessile invertebrates, zoantharians harbour a rich diversity of micro-organisms that can play a role in the biosynthesis of these natural products and we detail the current hypotheses on the metabolic pathways leading to the identified ecdysteroids, zoanthoxanthins, zoanthamines, palytoxins and others. Finally, we assess the possible use of these metabolites in the systematics of such a complex group of marine invertebrates and we discuss their possible ecological roles. Altogether, this review brings some insights into the rich chemical diversity of zoantharians and their potential for marine biodiscovery and marine ecology.
Topics: Animals; Anthozoa; Aquatic Organisms; Biological Products
PubMed: 31670367
DOI: 10.1039/c9np00043g -
Proceedings of the National Academy of... Dec 2020Reef-building corals and their aragonite (CaCO) skeletons support entire reef ecosystems, yet their formation mechanism is poorly understood. Here we used synchrotron...
Reef-building corals and their aragonite (CaCO) skeletons support entire reef ecosystems, yet their formation mechanism is poorly understood. Here we used synchrotron spectromicroscopy to observe the nanoscale mineralogy of fresh, forming skeletons from six species spanning all reef-forming coral morphologies: Branching, encrusting, massive, and table. In all species, hydrated and anhydrous amorphous calcium carbonate nanoparticles were precursors for skeletal growth, as previously observed in a single species. The amorphous precursors here were observed in tissue, between tissue and skeleton, and at growth fronts of the skeleton, within a low-density nano- or microporous layer varying in thickness from 7 to 20 µm. Brunauer-Emmett-Teller measurements, however, indicated that the mature skeletons at the microscale were space-filling, comparable to single crystals of geologic aragonite. Nanoparticles alone can never fill space completely, thus ion-by-ion filling must be invoked to fill interstitial pores. Such ion-by-ion diffusion and attachment may occur from the supersaturated calcifying fluid known to exist in corals, or from a dense liquid precursor, observed in synthetic systems but never in biogenic ones. Concomitant particle attachment and ion-by-ion filling was previously observed in synthetic calcite rhombohedra, but never in aragonite pseudohexagonal prisms, synthetic or biogenic, as observed here. Models for biomineral growth, isotope incorporation, and coral skeletons' resilience to ocean warming and acidification must take into account the dual formation mechanism, including particle attachment and ion-by-ion space filling.
Topics: Animals; Anthozoa; Bone and Bones; Coral Reefs; Ions; Models, Anatomic; Nanoparticles
PubMed: 33188087
DOI: 10.1073/pnas.2012025117 -
Seminars in Cell & Developmental Biology Oct 2015In the recent years several papers and some reviews have dealt with characterization, localization and influence on the precipitation of calcium carbonate, of the... (Review)
Review
In the recent years several papers and some reviews have dealt with characterization, localization and influence on the precipitation of calcium carbonate, of the organic matrix from scleractinian corals. In fact, it has been well established that coral calcification is a biological controlled process orchestrated in space and time by the organism also trough the secretion of organic matrix molecules because it has been well established that coral calcification is a biological controlled process, and thus is orchestrated in space and time by the organism also through the secretion of organic matrix molecules. In this review is presented a scientific path on the biomineralization of corals having as focusing point the intra-skeletal organic matrix, the molecules that are associated with mineral (aragonite). The review starts with a an overview on coral tissue, skeleton and tissue skeleton interface, describes the intra-skeletal organic matrix putting attention mainly on the proteins associated to aragonite and finally describes the in vivo and in vitro calcium carbonate precipitation experiments carried out aimed to evaluate the role of the organic matrix. The last paragraph reports studies on the role of the organic matrix in controlling calcification when corals are subject ocean acidification effects. The readers are expected to find a source of inspiration for new studies on the biomineralization of corals that are organic matrix addressed and merge diverse scientific disciplines.
Topics: Animals; Anthozoa; Calcification, Physiologic; Calcium Carbonate; Extracellular Matrix; Extracellular Matrix Proteins; Hydrogen-Ion Concentration; Microscopy, Electron, Scanning; Minerals; Seawater
PubMed: 26344100
DOI: 10.1016/j.semcdb.2015.09.005 -
The ISME Journal Feb 2020Reef-building corals harbour an astonishing diversity of microorganisms, including endosymbiotic microalgae, bacteria, archaea, and fungi. The metabolic interactions... (Review)
Review
Reef-building corals harbour an astonishing diversity of microorganisms, including endosymbiotic microalgae, bacteria, archaea, and fungi. The metabolic interactions within this symbiotic consortium are fundamental to the ecological success of corals and the unique productivity of coral reef ecosystems. Over the last two decades, scientific efforts have been primarily channelled into dissecting the symbioses occurring in coral tissues. Although easily accessible, this compartment is only 2-3 mm thick, whereas the underlying calcium carbonate skeleton occupies the vast internal volume of corals. Far from being devoid of life, the skeleton harbours a wide array of algae, endolithic fungi, heterotrophic bacteria, and other boring eukaryotes, often forming distinct bands visible to the bare eye. Some of the critical functions of these endolithic microorganisms in coral health, such as nutrient cycling and metabolite transfer, which could enable the survival of corals during thermal stress, have long been demonstrated. In addition, some of these microorganisms can dissolve calcium carbonate, weakening the coral skeleton and therefore may play a major role in reef erosion. Yet, experimental data are wanting due to methodological limitations. Recent technological and conceptual advances now allow us to tease apart the complex physical, ecological, and chemical interactions at the heart of coral endolithic microbial communities. These new capabilities have resulted in an excellent body of research and provide an exciting outlook to further address the functional microbial ecology of the "overlooked" coral skeleton.
Topics: Animals; Anthozoa; Archaea; Bacteria; Coral Reefs; Fungi; Microalgae; Microbiota; Symbiosis
PubMed: 31690886
DOI: 10.1038/s41396-019-0548-z -
Scientific Reports Jul 2020Research with coral embryos and larvae often requires laborious manual counting and sorting of individual specimens, usually via microscopy. Because many coral species...
Research with coral embryos and larvae often requires laborious manual counting and sorting of individual specimens, usually via microscopy. Because many coral species spawn only once per year during a narrow temporal window, sample processing is a time-limiting step for research on the early life-history stages of corals. Flow cytometry, an automated technique for measuring and sorting particles, cells, and cell-clusters, is a potential solution to this bottleneck. Yet most flow cytometers do not accommodate live organisms of the size of most coral embryos (> 250 µm), and sample processing is often destructive. Here we tested the ability of a large-particle flow cytometer with a gentle pneumatic sorting mechanism to process and spectrally sort live and preserved Montipora capitata coral embryos and larvae. Average survival rates of mechanically-sorted larvae were over 90% and were comparable to those achieved by careful hand-sorting. Preserved eggs and embryos remained intact throughout the sorting process and were successfully sorted based on real-time size and fluorescence detection. In-line bright-field microscopy images were captured for each sample object as it passed through the flow-cell, enabling the identification of early-stage embryos (2-cell to morula stage). Samples were counted and sorted at an average rate of 4 s larva and as high as 0.2 s larva for high-density samples. Results presented here suggest that large-particle flow cytometry has the potential to significantly increase efficiency and accuracy of data collection and sample processing during time-limited coral spawning events, facilitating larger-scale and higher-replication studies with an expanded number of species.
Topics: Animals; Anthozoa; Flow Cytometry; Larva
PubMed: 32737431
DOI: 10.1038/s41598-020-69491-0 -
Microbiology Spectrum Jun 2023Bleaching is one of the most relevant factors implicated in the integrity of coral reef ecosystems, with the increasing frequency and intensity of damaging events...
Bleaching is one of the most relevant factors implicated in the integrity of coral reef ecosystems, with the increasing frequency and intensity of damaging events representing a serious threat to reef biodiversity. Here, we analyzed changes in coral-associated bacteria from three types of non-bleached and bleached scleractinian corals (Acropora digitifera, Galaxea fascicularis, and Porites pukoensis) in Hainan Luhuitou peninsula coastal areas. The community structure of symbiotic bacteria differed significantly among the three apparently healthy corals. The bleached corals had higher bacterial alpha diversity and some specific bacteria genera, including , , , , , , , , Sva0996 marine group, , and unclassified_c_Gammaproteobacteria, were consistently increased in bleached groups. Network analysis revealed significantly different degrees of modularity between bleached and non-bleached groups at the bacterial genus level, and a higher proportion of links was dominated by positive co-occurrences. Functional prediction analysis illustrated that coral-associated bacteria remained relatively consistent in the bleached and non-bleached groups. Structure equation modeling revealed that the bacterial community diversity and function were directly influenced by host and environment factors. These findings suggested that coral-associated bacterial responses to bleaching occur in a host-dependent manner, informing novel strategies for restoring coral and aiding adaption to bleaching stress. Accumulating evidence indicates that coral-associated bacteria play an important role in the health of holobionts. However, the variability of the symbiotic bacterial community structure among coral species with different coral health statuses remains largely unknown. Here, we investigated three apparent non-bleached (healthy) and bleached coral species (sampled ), involving related symbiotic bacterial profiles, including composition, alpha diversity, network relationship, and potential function. Structural equation modeling analysis was used to analyze the relationship between coral status and abiotic and biotic factors. The bacterial community structure of different groups was shown to exhibit host-specific traits. Both host and environmental impacts had primary effects on coral-associated microbial communities. Future studies are needed to identify the mechanisms that mediate divergent microbial consortia.
Topics: Animals; Anthozoa; Bacteria; Coral Reefs; Microbiota; Gammaproteobacteria
PubMed: 37191552
DOI: 10.1128/spectrum.04910-22 -
BioEssays : News and Reviews in... Aug 2018Coral bleaching has attracted considerable study, yet one central question remains unanswered: given that corals and their Symbiodinium symbionts have co-evolved for... (Review)
Review
Coral bleaching has attracted considerable study, yet one central question remains unanswered: given that corals and their Symbiodinium symbionts have co-evolved for millions of years, why does this clearly maladaptive process occur? Bleaching may result from evolutionary conflict between the host corals and their symbionts. Selection at the level of the individual symbiont favors using the products of photosynthesis for selfish replication, while selection at the higher level favors using these products for growth of the entire host/symbiont community. To hold the selfish lower-level units in check, mechanisms of conflict mediation must evolve. Fundamental features of photosynthesis have been co-opted into conflict mediation so that symbionts that fail to export these products produce high levels of reactive oxygen species and undergo programmed cell death. These mechanisms function very well under most environmental conditions, but under conditions particularly detrimental to photosynthesis, it is these mechanisms of conflict mediation that trigger bleaching.
Topics: Animals; Anthozoa; Biological Evolution; Dinoflagellida; Photosynthesis; Reactive Oxygen Species; Selection, Genetic; Symbiosis
PubMed: 29944191
DOI: 10.1002/bies.201800021 -
Nature Chemical Biology Jun 2022Diterpenes are major defensive small molecules that enable soft corals to survive without a tough exterior skeleton, and, until now, their biosynthetic origin has...
Diterpenes are major defensive small molecules that enable soft corals to survive without a tough exterior skeleton, and, until now, their biosynthetic origin has remained intractable. Furthermore, biomedical application of these molecules has been hampered by lack of supply. Here, we identify and characterize coral-encoded terpene cyclase genes that produce the eunicellane precursor of eleutherobin and cembrene, representative precursors for the >2,500 terpenes found in octocorals. Related genes are found in all sequenced octocorals and form their own clade, indicating a potential ancient origin concomitant with the split between the hard and soft corals. Eleutherobin biosynthetic genes are colocalized in a single chromosomal region. This demonstrates that, like plants and microbes, animals also harbor defensive biosynthetic gene clusters, supporting a recombinational model to explain why specialized or defensive metabolites are adjacently encoded in the genome.
Topics: Animals; Anthozoa; Chromosomes; Genome; Multigene Family; Terpenes
PubMed: 35606556
DOI: 10.1038/s41589-022-01027-1 -
Scientific Reports Feb 2019Corals comprise a biomineralizing cnidarian, dinoflagellate algal symbionts, and associated microbiome of prokaryotes and viruses. Ongoing efforts to conserve coral...
Corals comprise a biomineralizing cnidarian, dinoflagellate algal symbionts, and associated microbiome of prokaryotes and viruses. Ongoing efforts to conserve coral reefs by identifying the major stress response pathways and thereby laying the foundation to select resistant genotypes rely on a robust genomic foundation. Here we generated and analyzed a high quality long-read based ~886 Mbp nuclear genome assembly and transcriptome data from the dominant rice coral, Montipora capitata from Hawai'i. Our work provides insights into the architecture of coral genomes and shows how they differ in size and gene inventory, putatively due to population size variation. We describe a recent example of foreign gene acquisition via a bacterial gene transfer agent and illustrate the major pathways of stress response that can be used to predict regulatory components of the transcriptional networks in M. capitata. These genomic resources provide insights into the adaptive potential of these sessile, long-lived species in both natural and human influenced environments and facilitate functional and population genomic studies aimed at Hawaiian reef restoration and conservation.
Topics: Animals; Anthozoa; Genome; Stress, Physiological; Transcription, Genetic
PubMed: 30796282
DOI: 10.1038/s41598-019-39274-3 -
Current Biology : CB Oct 2022Corals have long been known to generate local fluid flows using ciliary beating, but the importance of these ciliary flows is just being discovered. Two new papers shed...
Corals have long been known to generate local fluid flows using ciliary beating, but the importance of these ciliary flows is just being discovered. Two new papers shed light on how ciliary-flow physics plays a key role in shaping coral physiology.
Topics: Animals; Anthozoa; Coral Reefs
PubMed: 36220095
DOI: 10.1016/j.cub.2022.08.049