Name: Coral Metabolism Quenching and Coral Tissue Removal from Coral Skeleton
Uploaded: 2023-10-13T13:30:00
Description: Watch this Scientific Journal Video about Coral Metabolism Quenching and Coral Tissue Removal from Coral Skeleton at JoVE.com

coral metabolism quenching and coral tissue removal from coral skeleton

使用 GC-MS 对硬珊瑚样品进行代谢物分析

Metabolites represent the end products of cellular processes, and metabolomics - the study of the suite of metabolites produced by a given organism or ecosystem - can provide a direct measure of organismal functioning1. This is particularly critical for exploring ecosystems, symbiotic interactions, and restoration tools, as the goal of most management strategies is to preserve (or restore) specific ecosystem service functions2. Coral reefs are one aquatic ecosystem that demonstrates the potential value of metabolomics for elucidating symbiotic interactions and linking coral physiological responses to community-level and ecosystem-level impacts3. The application of high-throughput gas chromatography-mass spectrometry (GC-MS) is especially valued due to its capacity to rapidly analyze a broad range of metabolite classes simultaneously with high selectivity and sensitivity, provide rapid compound identification when spectral libraries are available, and provide a high level of reproducibility and accuracy, with a relatively low cost per sample.
Corals are holobionts consisting of the coral animal, photosynthetic dinoflagellate endosymbionts (family: Symbiodiniaceae4), and a complex microbiome5,6. Overall, the fitness of the holobiont is maintained primarily through the exchange of small molecules and elements to support the metabolic functioning of each member7,8,9,10. Metabolomic approaches have proven especially powerful for elucidating the metabolic basis of symbiosis specificity9,11, the bleaching response to thermal stress7,8,12,13, disease responses14, pollution exposure responses15, photoacclimation16, and chemical signalling17 in corals, as well as aiding in biomarker discovery18,19. Additionally, metabolomics can provide valuable confirmation of the conclusions inferred from DNA- and RNA-based techniques9,20. There is, therefore, considerable potential for the use of metabolomics for assessing reef health and developing tools for reef conservation3, such as through the detection of metabolic biomarkers of stress18,19 and for examining the potential of active management strategies such as nutritional subsidies21.
Separating the host and symbiont cells and analyzing their metabolite profiles independently, rather than together as the holobiont, can yield more information about the partner interactions, independent physiological and metabolic statuses, and potential molecular mechanisms for adaptation11,12,22,23,24. Without separating the coral and Symbiodiniaceae, it is almost impossible to elucidate the contribution and metabolism of coral and/or Symbiodiniaceae independently, except for with complex genome reconstruction and metabolic modeling25, but this has yet to be applied to the coral-dinoflagellate symbiosis. Furthermore, attempting to extract information about the individual metabolism of the host or algal symbiont from the metabolite profile of the holobiont can lead to misinterpretation.
For example, until recently, the presence of C18:3n-6, C18:4n-3, and C16 polyunsaturated fatty acids in extracts from coral and holobiont tissues was thought to be derived from the algal symbiont, as corals were assumed to not possess the &#969;x desaturases essential for the production of omega-3 (&#969;3) fatty acids; however, recent genomic evidence suggests that multiple cnidarians have the ability to produce &#969;3 PUFA de novo and further biosynthesize &#969;3 long-chain PUFA26. Combining GC-MS with stable isotopic labeling (e.g., 13C-bicarbonate, NaH13CO3) can be used to track the fate of photosynthetically fixed carbon through coral holobiont metabolic networks under both control conditions and in response to external stressors27,28. However, a critical step in the tracking of 13C fate is the separation of the coral tissue from the algal cells-only then can the presence of a 13C-labeled compound in the coral host fraction be unequivocally assigned as a Symbiodiniaceae-derived metabolite translocated to the coral or a downstream product of a translocated labeled compound. This technique has demonstrated its power by challenging the long-held assumption that glycerol is the primary form in which photosynthate is translocated from symbiont to host29, as well as elucidating how inter-partner nutritional flux changes during bleaching27,28 and in response to incompatible Symbiodiniaceae species11.
While the decision to separate tissues is primarily driven by the research question, the practicality, reliability, and potential metabolic impacts of this approach are important to consider. Here, we provide detailed, demonstrated methods for the extraction of metabolites from the holobiont, as well as the separate host and symbiont fractions. We compare the metabolite profiles of the host and symbiont independently and how these profiles compare to the holobiont metabolite profile.

作者聚焦：珊瑚宿主组织和藻类共生体的分离及其代谢物分析 

基于气相色谱-质谱的硬珊瑚样品靶向代谢组学研究

As with every organism, corals depend on superlative nutrition to grow and construct reefs for immunity and reproduction and to withstand changing environmental conditions. But we know very little about optimal nutrition for corals under normal or changing conditions, and how each member of the coral holobiont contributes to this nutritional status. Corals are holobionts comprised of the host and various symbiotic microorganisms.These include Symbiodiniaceae, protists, bacteria, viruses, and fungi. The fitness of the holobiont depends on the metabolic interactions between these members. For instance, Symbiodiniaceae provide photosynthate to support the host's metabolism and help it adapt to changing conditions.To understand this crucial partnership, we need to study each partner's chemical and metabolic composition separately. These findings demonstrated that more information could be obtained by separating host and symbiont fractions for metabolic analysis. However, the decision to analyze separate fractions versus the holobiont is ultimately governed by the research question.So in cases where analysis of the holobiont is preferable, we provided a methodology for holobiont metabolite extractions, and suggestions to obtain as much information as possible during analysis. The methods used in this study open up new avenues for research. These include revealing potential biomarkers, identifying key metabolites during specific life stages or stress conditions, understanding the advantages of associating with certain species, and exploring interactions within the holobiont.Future research will focus on applying the protocols established here to several research areas, including the detection of biomarkers with applications in coral reef conservation and restoration. This methodology can also be applied where the separation of fractions isn't possible for other physiological measures. For example, when analyzing volatile metabolite emissions from coral colonies.

Watch this Scientific Journal Video about Coral Metabolism Quenching and Coral Tissue Removal from Coral Skeleton at JoVE.com

Coral Metabolism Quenching and Coral Tissue Removal from Coral Skeleton  

珊瑚代谢淬灭和珊瑚骨架上的珊瑚组织去除

首先，从装有珊瑚碎片的样品收集袋中排出多余的海水。将样品浸入液氮中至少 30 秒。要从骨骼中取出珊瑚组织，请将无菌样本收集袋放在冰上，确保其稳定且开放，但不会浸入冰中。在袋子中加入 10 毫升冷超纯水。使用无菌镊子，选择放置在冰上的珊瑚碎片，然后用冷的超纯水冲洗，直到没有海水残留物。将冲洗干净的珊瑚碎片放入装有超纯水的袋子中。接下来，切开一毫升移液器吸头的大约五毫米末端，并用电工胶带将其粘在气枪的末端。将气枪对准珊瑚碎片，将袋子半密封，气流在低介质上，在碎片上使用圆周水运动轻轻去除组织。三分钟后，或当所有组织从骨骼中取出时，关闭空气并取下喷枪。将袋子完全密封，并将所有去除的珊瑚组织挤入袋子的底角。切掉袋子的对角，轻轻地将内容物倒入冰上的 15 毫升管中。

Research

JoVE Journal

Biology

Coral Metabolism Quenching and Coral Tissue Removal from Coral Skeleton

Gas Chromatography-Mass Spectrometry-Based Targeted Metabolomics of Hard Coral Samples

Gas chromatography-mass spectrometry (GC-MS)-based approaches have proven to be powerful for elucidating the metabolic basis of the ...

科研

生物学

Separation of Coral Host Tissues and Symbiodiniaceae Cells for Metabolite Extractions

分离珊瑚宿主组织和共生菌科细胞进行代谢物提取

Preparation of Metabolites from a Coral Holobiont, Separated Coral Host Tissue, and Symbiodiniaceae Cells for Gas Chromatography-Mass Spectrometry Analysis