Moon Jellyfish Aurelia Aurita Research Articles

Marine bacteriophages disturb the associated microbiota of Aurelia aurita with a recoverable effect on host morphology.

The concept of the metaorganism describes a multicellular host and its diverse microbial community, which form one biological unit with a combined genetic repertoire that significantly influences health and survival of the host. The present study delved into the emerging field of bacteriophage research within metaorganisms, focusing on the moon jellyfish Aurelia aurita as a model organism. The previously isolated Pseudomonas phage BSwM KMM1 and Citrobacter phages BSwM KMM2 - KMM4 demonstrated potent infectivity on bacteria present in the A. aurita-associated microbiota. In a host-fitness experiment, Baltic Sea subpopulation polyps were exposed to individual phages and a phage cocktail, monitoring polyp survival and morphology, as well as microbiome changes. The following effects were obtained. First, phage exposure in general led to recoverable malformations in polyps without affecting their survival. Second, analyses of the community structure, using 16S rRNA amplicon sequencing, revealed alterations in the associated microbial community in response to phage exposure. Third, the native microbiota is dominated by an uncultured likely novel Mycoplasma species, potentially specific to A. aurita. Notably, this main colonizer showed resilience through the recovery after initial declines, which aligned with abundance changes in Bacteroidota and Proteobacteria, suggesting a dynamic and adaptable microbial community. Overall, this study demonstrates the resilience of the A. aurita metaorganism facing phage-induced perturbations, emphasizing the importance of understanding host-phage interactions in metaorganism biology. These findings have implications for ecological adaptation and conservation in the rapidly changing marine environment, particularly regarding the regulation of blooming species and the health of marine ecosystems during ongoing environmental changes.

Antimicrobial Peptides Originating from Expression Libraries of Aurelia aurita and Mnemiopsis leidyi Prevent Biofilm Formation of Opportunistic Pathogens.

The demand for novel antimicrobial compounds is rapidly growing due to the rising appearance of antibiotic resistance in bacteria; accordingly, alternative approaches are urgently needed. Antimicrobial peptides (AMPs) are promising, since they are a naturally occurring part of the innate immune system and display remarkable broad-spectrum activity and high selectivity against various microbes. Marine invertebrates are a primary resource of natural AMPs. Consequently, cDNA expression (EST) libraries from the Cnidarian moon jellyfish Aurelia aurita and the Ctenophore comb jelly Mnemiopsis leidyi were constructed in Escherichia coli. Cell-free size-fractionated cell extracts (<3 kDa) of the two libraries (each with 29,952 clones) were consecutively screened for peptides preventing the biofilm formation of opportunistic pathogens using the crystal violet assay. The 3 kDa fraction of ten individual clones demonstrated promising biofilm-preventing activities against Klebsiella oxytoca and Staphylococcus epidermidis. Sequencing the respective activity-conferring inserts allowed for the identification of small ORFs encoding peptides (10-22 aa), which were subsequently chemically synthesized to validate their inhibitory potential. Although the peptides are likely artificial products from a random translation of EST inserts, the biofilm-preventing effects against K. oxytoca, Pseudomonas aeruginosa, S. epidermidis, and S. aureus were verified for five synthetic peptides in a concentration-dependent manner, with peptide BiP_Aa_5 showing the strongest effects. The impact of BiP_Aa_2, BiP_Aa_5, and BiP_Aa_6 on the dynamic biofilm formation of K. oxytoca was further validated in microfluidic flow cells, demonstrating a significant reduction in biofilm thickness and volume by BiP_Aa_2 and BiP_Aa_5. Overall, the structural characteristics of the marine invertebrate-derived AMPs, their physicochemical properties, and their promising antibiofilm effects highlight them as attractive candidates for discovering new antimicrobials.

Four Novel Caudoviricetes Bacteriophages Isolated from Baltic Sea Water Infect Colonizers of Aurelia aurita.

The moon jellyfish Aurelia aurita is associated with a highly diverse microbiota changing with provenance, tissue, and life stage. While the crucial relevance of bacteria to host fitness is well known, bacteriophages have often been neglected. Here, we aimed to isolate virulent phages targeting bacteria that are part of the A. aurita-associated microbiota. Four phages (Pseudomonas phage BSwM KMM1, Citrobacter phages BSwM KMM2-BSwM KMM4) were isolated from the Baltic Sea water column and characterized. Phages KMM2/3/4 infected representatives of Citrobacter, Shigella, and Escherichia (Enterobacteriaceae), whereas KMM1 showed a remarkably broad host range, infecting Gram-negative Pseudomonas as well as Gram-positive Staphylococcus. All phages showed an up to 99% adsorption to host cells within 5 min, short latent periods (around 30 min), large burst sizes (mean of 128 pfu/cell), and high efficiency of plating (EOP > 0.5), demonstrating decent virulence, efficiency, and infectivity. Transmission electron microscopy and viral genome analysis revealed that all phages are novel species and belong to the class of Caudoviricetes harboring a tail and linear double-stranded DNA (formerly known as Siphovirus-like (KMM3) and Myovirus-like (KMM1/2/4) bacteriophages) with genome sizes between 50 and 138 kbp. In the future, these isolates will allow manipulation of the A. aurita-associated microbiota and provide new insights into phage impact on the multicellular host.

Embryonic development of the moon jellyfish Aurelia aurita (Cnidaria, Scyphozoa): another variant on the theme of invagination.

BackgroundAurelia aurita (Scyphozoa, Cnidaria) is an emblematic species of the jellyfish. Currently, it is an emerging model of Evo-Devo for studying evolution and molecular regulation of metazoans’ complex life cycle, early development, and cell differentiation. For Aurelia, the genome was sequenced, the molecular cascades involved in the life cycle transitions were characterized, and embryogenesis was studied on the level of gross morphology. As a reliable representative of the class Scyphozoa, Aurelia can be used for comparative analysis of embryonic development within Cnidaria and between Cnidaria and Bilateria. One of the intriguing questions that can be posed is whether the invagination occurring during gastrulation of different cnidarians relies on the same cellular mechanisms. To answer this question, a detailed study of the cellular mechanisms underlying the early development of Aurelia is required.MethodsWe studied the embryogenesis of A. aurita using the modern methods of light microscopy, immunocytochemistry, confocal laser microscopy, scanning and transmission electron microscopy.ResultsIn this article, we report a comprehensive study of the early development of A. aurita from the White Sea population. We described in detail the embryonic development of A. aurita from early cleavage up to the planula larva. We focused mainly on the cell morphogenetic movements underlying gastrulation. The dynamics of cell shape changes and cell behavior during invagination of the archenteron (future endoderm) were characterized. That allowed comparing the gastrulation by invagination in two cnidarian species—scyphozoan A. aurita and anthozoan Nematostella vectensis. We described the successive stages of blastopore closure and found that segregation of the germ layers in A. aurita is linked to the ’healing’ of the blastopore lip. We followed the developmental origin of the planula body parts and characterized the planula cells’ ultrastructure. We also found that the planula endoderm consists of three morphologically distinct compartments along the oral-aboral axis.ConclusionsEpithelial invagination is a fundamental morphogenetic movement that is believed as highly conserved across metazoans. Our data on the cell shaping and behaviours driving invagination in A. aurita contribute to understanding of morphologically similar morphogenesis in different animals. By comparative analysis, we clearly show that invagination may differ at the cellular level between cnidarian species belonging to different classes (Anthozoa and Scyphozoa). The number of cells involved in invagination, the dynamics of the shape of the archenteron cells, the stage of epithelial-mesenchymal transition that these cells can reach, and the fate of blastopore lip cells may vary greatly between species. These results help to gain insight into the evolution of morphogenesis within the Cnidaria and within Metazoa in general.

Shorter, warmer winters may inhibit production of ephyrae in a population of the moon jellyfish Aurelia aurita

Scyphozoan jellyfish blooms display high interannual variability in terms of timing of appearance and size of the bloom. To understand the causes of this variability, the conditions experienced by the polyps prior to the production of ephyrae in the spring were examined. Polyps reared from planula larvae of Aurelia aurita medusae collected from southern England (50°49′58.8; − 1°05′36.9) were incubated under orthogonal combinations of temperature (4, 7, 10 °C) and duration (2, 4, 6, 8 weeks), representing the range of winter conditions in that region, before experiencing an increase to 13 °C. Timing and success of strobilation were recorded. No significant production of ephyrae was observed in any of the 2- and 4-week incubations, or in any 10 °C incubation. Time to first ephyra release decreased with longer winter incubations, and more ephyrae were produced following longer and colder winter simulations. This experiment indicates that A. aurita requires a minimum period of cooler temperatures to strobilate, and contradicts claims that jellyfish populations will be more prevalent in warming oceans, specifically in the context of warmer winter conditions. Such investigations on population-specific ontogeny highlights the need to examine each life stage separately as well as in the context of its environment.

The Native Microbiome is Crucial for Offspring Generation and Fitness of Aurelia aurita.

All multicellular organisms are associated with microbial communities, ultimately forming a metaorganism. Several studies conducted on well-established model organisms point to immunological, metabolic, and behavioral benefits of the associated microbiota for the host. Consequently, a microbiome can influence the physiology of a host; moreover, microbial community shifts can affect host health and fitness. The present study aimed to evaluate the significance and functional role of the native microbiota for life cycle transitions and fitness of the cnidarian moon jellyfish Aurelia aurita A comprehensive host fitness experiment was conducted studying the polyp life stage and integrating 12 combinations of treatments with microbiota modification (sterile conditions, foreign food bacteria, and potential pathogens). Asexual reproduction, e.g., generation of daughter polyps, and the formation and release of ephyrae were highly affected in the absence of the native microbiota, ultimately resulting in a halt of strobilation and ephyra release. Assessment of further fitness traits showed that health, growth, and feeding rate were decreased in the absence and upon community changes of the native microbiota, e.g., when challenged with selected bacteria. Moreover, changes in microbial community patterns were detected by 16S rRNA amplicon sequencing during the course of the experiment. This demonstrated that six operational taxonomic units (OTUs) significantly correlated and explained up to 97% of fitness data variability, strongly supporting the association of impaired fitness with the absence/presence of specific bacteria. Conclusively, our study provides new insights into the importance and function of the microbiome for asexual reproduction, health, and fitness of the basal metazoan A. auritaIMPORTANCE All multicellular organisms are associated with a diverse and specific community of microorganisms; consequently, the microbiome is of fundamental importance for health and fitness of the multicellular host. However, studies on microbiome contribution to host fitness are in their infancy, in particular, for less well-established hosts such as the moon jellyfish Aurelia aurita Here, we studied the impact of the native microbiome on the asexual reproduction and on further fitness traits (health, growth, and feeding) of the basal metazoan due to induced changes in its microbiome. We observed significant impact on all fitness traits analyzed, in particular, in the absence of the protective microbial shield and when challenged with marine potentially pathogenic bacterial isolates. Notable is the identified crucial importance of the native microbiome for the generation of offspring, consequently affecting life cycle decisions. Thus, we conclude that the microbiome is essential for the maintenance of a healthy metaorganism.

Ecological drivers of jellyfish blooms - The complex life history of a 'well-known' medusa (Aurelia aurita).

Jellyfish blooms are conspicuous demographic events with significant ecological and socio-economic impact. Despite worldwide concern about an increased frequency and intensity of such mass occurrences, predicting their booms and busts remains challenging. Forecasting how jellyfish populations may respond to environmental change requires considering their complex life histories. Metagenic life cycles, which include a benthic polyp stage, can boost jellyfish mass occurrences via asexual recruitment of pelagic medusae. Here we present stage-structured matrix population models with monthly, individual-based demographic rates of all life stages of the moon jellyfish Aurelia aurita L. (sensu stricto). We investigate the life-stage dynamics of these complex populations under low and high food conditions to illustrate how changes in medusa density depend on non-medusa stage dynamics. We show that increased food availability can be an important ecological driver of jellyfish mass occurrences, as it can temporarily shift the population structure from polyp- to medusa-dominated. Projecting populations for a winter warming scenario additionally enhanced the booms and busts of jellyfish blooms. We identify demographic key variables that control the intensity and frequency of jellyfish blooms in response to environmental drivers such as habitat eutrophication and climate change. By contributing to an improved understanding of mass occurrence phenomena, our findings provide perspective for future management of ecosystem health.

Visualization of Rotational Swimming Patterns in Oblate Jellyfish

Kim, S.; Pyeon, Y.; Lee, K.; Kim, P.; Oh, W., and Choi, J.H., 2020. Visualization of rotational swimming patterns in oblate jellyfish. Journal of Coastal Research, 36(2), 289–294. Coconut Creek (Florida), ISSN 0749-0208.To identify the swimming mechanism of jellyfish, the present study conducted observational experiments using particle image velocimetry in a relatively flat and oblate-shaped jellyfish, the moon jellyfish (Aurelia aurita). The formation of vortices around the left and right edges of the jellyfish's bell and the associated vorticity structures that formed during rotational swimming were analyzed. The effects of variation in the width-to-height ratio of the jellyfish during rotational swimming were also investigated. Moon jellyfish generated locomotor structures with velocities faster than their neighboring flow velocities by producing paddling motions at the left and right edges of the bell at width-to-height ratios more than 0.531. Faster locomotor structures were not observed at width-to-height ratios less than 0.496. Moreover, jellyfish tended to rotate in a counterclockwise direction from the central axis of the body. With respect to paddling speed, and according to changes in the width-to-height ratio, the left edge was, on average, 25% faster than the right edge. The left edge, where the central axis of rotation is located, exhibited a 40% reduction in its rotational angle when paddling speed was decreased by 87%. This study lays the methodological foundation for further studies to investigate how variation in environmental conditions affect jellyfish locomotion and how locomotion varies among species.

Cryptic diets of forage fish: jellyfish consumption observed in the Celtic Sea and western English Channel.

To establish if fishes’ consumption of jellyfish changes through the year, we conducted a molecular gut‐content assessment on opportunistically sampled species from the Celtic Sea in October and compared these with samples previously collected in February and March from the Irish Sea. Mackerel Scomber scombrus were found to feed on hydrozoan jellyfish relatively frequently in autumn, with rare consumption also detected in sardine Sardina pilchardus and sprat Sprattus sprattus. By October, moon jellyfish Aurelia aurita appeared to have escaped predation, potentially through somatic growth and the development of stinging tentacles. This is in contrast with sampling in February and March where A. aurita ephyrae were heavily preyed upon. No significant change in predation rate was observed in S. sprattus, but jellyfish predation by S. scombrus feeding in autumn was significantly higher than that seen during winter. This increase in consumption appears to be driven by the consumption of different, smaller jellyfish species than were targeted during the winter.

Potential role of host-derived quorum quenching in modulating bacterial colonization in the moon jellyfish Aurelia aurita

Multicellular organisms can be regarded as metaorganisms, comprising of a macroscopic host interacting with associated microorganisms. Within this alliance, the host has to ensure attracting beneficial bacteria and defending against pathogens to establish and maintain a healthy homeostasis. Here, we obtained several lines of evidence arguing that Aurelia aurita uses interference with bacterial quorum sensing (QS) - quorum quenching (QQ) - as one host defense mechanism. Three A. aurita-derived proteins interfering with bacterial QS were identified by functionally screening a metagenomic library constructed from medusa-derived mucus. Native expression patterns of these host open reading frames (ORFs) differed in the diverse life stages (associated with different microbiota) pointing to a specific role in establishing the developmental stage-specific microbiota. Highly increased expression of all QQ-ORFs in germ-free animals further indicates their impact on the microbiota. Moreover, incubation of native animals with pathogenic bacteria induced expression of the identified QQ-ORFs arguing for a host defense strategy against confronting bacteria by interference with bacterial QS. In agreement, immobilized recombinant QQ proteins induced restructuring of polyp-associated microbiota through changing abundance and operational taxonomic unit composition. Thus, we hypothesize that additional to the immune system host-derived QQ-activities potentially control bacterial colonization.

Mechanisms underlying heterogeneous distribution of moon jellyfish Aurelia aurita s.l. across a sharp pycnocline

Mechanisms underlying heterogeneous distribution of moon jellyfish Aurelia aurita s.l. across a sharp pycnocline

Behavior and Frequency Analysis of Aurelia aurita by Using in situ Target Strength at a Port in Southwestern Korea

This study was carried out to determine the in situ target strength and behavioral characteristics of moon jellyfish (Aurelia aurita) using two frequencies (38 and 120 kHz) that present a 2- frequency-difference method for distinguishing A. aurita from other marine planktonic organisms. The average TS was shown as -71.9~ -67.9 dB at 38 kHz and -75.5~-66.0 dB at 120 kHz and the average ΔMVBS120-38 kHz was similar at -1.5~3.5 dB. The TS values varied in a range of about 14 dB from -83.3 and -69.0 dB depending on the pulsation of A. aurita. The species moved in a range of -0.1~1.0 m and they mostly moved horizontally with moving speeds of 0.3~0.6 m·s-1. The TS and behavioral characteristics of A. aurita can distinguish the species from others. The acoustic technology can also contribute to understanding the distribution and abundance of the species.

Indoles induce metamorphosis in a broad diversity of jellyfish, but not in a crown jelly (Coronatae).

Many animals go through one or more metamorphoses during their lives, however, the molecular underpinnings of metamorphosis across diverse species are not well understood. Medusozoa (Cnidaria) is a clade of animals with complex life cycles, these life cycles can include a polyp stage that metamorphoses into a medusa (jellyfish). Medusae are produced through a variety of different developmental mechanisms—in some species polyps bud medusae (Hydrozoa), in others medusae are formed through polyp fission (Scyphozoa), while in others medusae are formed through direct transformation of the polyp (Cubozoa). To better understand the molecular mechanisms that may coordinate these different forms of metamorphosis, we tested two compounds first identified to induce metamorphosis in the moon jellyfish Aurelia aurita (indomethacin and 5-methoxy-2-methylindole) on a broad diversity of medusozoan polyps. We discovered that indole-containing compounds trigger metamorphosis across a broad diversity of species. All tested discomedusan polyps metamorphosed in the presence of both compounds, including species representatives of several major lineages within the clade (Pelagiidae, Cyaneidae, both clades of Rhizostomeae). In a cubozoan, low levels of 5-methoxy-2-methylindole reliably induced complete and healthy metamorphosis. In contrast, neither compound induced medusa metamorphosis in a coronate scyphozoan, or medusa production in either hydrozoan tested. Our results support the hypothesis that metamorphosis is mediated by a conserved induction pathway within discomedusan scyphozoans, and possibly cubozoans. However, failure of these compounds to induce metamorphosis in a coronate suggests this induction mechanism may have been lost in this clade, or is convergent between Scyphozoa and Cubozoa.

Incidental consumption of ephyrae of moon jellyfish Aurelia aurita s.l. by three filter-feeding sessile organisms: laboratory experiments

Moon jellyfish Aurelia aurita s.l. has been suggested to have high mortality during the ephyra stage, which potentially affects the population size of the later medusa stage. However, the mechanism behind the high mortality rate has still not been clarified. Ephyrae of A. aurita are liberated from the sessile strobila, which are usually surrounded by filter-feeding sessile organisms. In the present study, we carried out a series of feeding trials at 10 °C, offering A. aurita ephyrae to three potential predatory filter-feeding sessile organisms: the mussel Mytilus galloprovincialis, the ascidian Styela plicata, and the barnacle Amphibalanus eburneus. From the experiments, the mussel was estimated to have the highest ability to consume ephyrae among the sessile organisms. Size-selective filtration experiments showed that the mussel consumed newly liberated ephyrae [3 mm total body diameter (TBD)] at a significantly higher efficiency than larger (5 and 7 mm TBD) ephyrae. Our results demonstrate that filter-feeding sessile organisms, especially the mussel, are potential consumers of the early ephyra stage.

Withstanding multiple stressors: ephyrae of the moon jellyfish (Aurelia aurita, Scyphozoa) in a high-temperature, high-CO2 and low-oxygen environment

Global change is affecting marine ecosystems through a combination of different stressors such as warming, ocean acidification and oxygen depletion. Very little is known about the interactions among these factors, especially with respect to gelatinous zooplankton. Therefore, in this study we investigated the direct effects of pH, temperature and oxygen availability on the moon jellyfish Aurelia aurita, concentrating on the ephyral life stage. Starved one-day-old ephyrae were exposed to a range of pCO2 (400–4000 ppm) and three different dissolved oxygen levels (from saturated to hypoxic conditions), in two different temperatures (5 and 15 °C) for 7 days. Carbon content and swimming activity were analysed at the end of the incubation period, and mortality noted. General linearized models were fitted through the data, with the best fitting models including two- and three-way interactions between pCO2, temperature and oxygen concentration. The combined effect of the stressors was small but significant, with the clearest negative effect on growth caused by the combination of all three stressors present (high temperature, high CO2, low oxygen). We conclude that A. aurita ephyrae are robust and that they are not likely to suffer from these environmental stressors in a near future.

Reduced pH affects pulsing behaviour and body size in ephyrae of the moon jellyfish, Aurelia aurita

Our understanding of how reduced seawater pH affects the behaviour and growth of scyphozoan jellyfish is poor. Here, we investigated the effects of simulated Ocean Acidification (OA) (pH=7.6 for 7d) on pulsing behaviour (as an index of swimming behaviour) and aspects of the morphology of ephyrae of the moon jellyfish Aurelia aurita. Ephyrae exposed to reduced pH had a significantly smaller surface area, central disc area, and lappet length and width than controls. Pulsation rate was significantly lower, and the mean pulse-to-pulse period shorter, in the reduced pH treatment. There was, however, no significant treatment effect on either the maximum or minimum pulse-to-pulse period, suggesting that the ability for rapid pulsations was maintained. Ephyrae from the reduced pH treatment displayed a more variable pulsation behaviour, with an elevated standard deviation and root mean square of successive difference (RMSSD) in pulse-to-pulse period. In summary, reduced pH simulating future predicted Ocean Acidification conditions, had important effects on aspects of swimming behaviour and size of A. aurita ephyra, which may have consequences for survival and the population dynamics of field populations.

Herbivorous fishes Siganus rivulatus (Siganidae) and Zebrasoma desjardinii (Acanthuridae) feed on Ctenophora and Scyphozoa in the Red Sea

Individuals of the rabbitfish Siganus rivulatus (Siganidae) and surgeonfish Zebrasoma desjardinii (Acanthuridae) were observed feeding on ctenophores and scyphozoans in the northern Red Sea during late spring and early summer seasons between 2010 and 2015. Siganus rivulatus and Z. desjardinii, considered nominally herbivorous, preyed on relatively large ctenophores until disintegration, and on the moon jellyfish Aurelia aurita (Scyphozoa) until they sank to the bottom. Siganus rivulatus was the most dominant predatory fish feeding on gelatinous zooplankton (37 % of attacks on ctenophores and 51 % of attacks on A. aurita). Furthermore, prey individuals were usually approached by two or more fish simultaneously. Eleven additional fish species fed on gelatinous zooplankton, with Chaetodon fasciatus (Chaetodontidae) accounting for 27 and 12 % of the attacks on ctenophores and A. aurita, respectively, and Z. desjardinii for 17 and 24 % of the attacks. Other fishes attacked gelatinous zooplankton in ≤6 % of the observations. This study constitutes the first record of S. rivulatus and Z. desjardinii preying on ctenophores and also confirms preliminary observations of S. rivulatus feeding on scyphozoans. Although herbivorous fishes may accidentally ingest small invertebrates while feeding on algae, the deliberate feeding on gelatinous zooplankton observed for S. rivulatus and Z. desjardinii suggests that their trophic role should be reevaluated.

Does temperature and salinity limit asexual reproduction of Aurelia aurita polyps (Cnidaria: Scyphozoa) in the Gulf of Gdańsk (southern Baltic Sea)? An experimental study

Outbreaks of the moon jellyfish Aurelia aurita occur seasonally in the Gulf of Gdansk (southern Baltic Sea), but field observations of sedentary polyps are scarce suggesting that asexual reproduction of scyphistomae is restricted in this water basin. This study has been set up to investigate the effects of temperature (3, 5, 10, 15, 20 and 25°C) and salinity (2, 4, 7, 12 and 18 PSU) on polyp strobilation and budding under gradually changing exposure conditions. Duration and intensity of strobilation increased in low temperatures, while higher temperatures reduced (20°C) and ceased (25°C) production of ephyrae and enhanced budding activity. The asexual reproduction is therefore synchronized well with environmental conditions with strobilation occurring in spring and autumn/winter and growth of colonies (budding) taking place in summer. This provides a potential of scyphistomae to develop benthic colonies and support population size of medusae in the gulf. Salinity of 4 PSU caused absorption of tentacles and in 2 PSU, 100% mortality of polyps was observed indicating high sensitivity of scyphistomae to low salinity. An increase in water salinity induced more numerous strobilation as well as enhanced and longer budding suggesting that scyphopolyps can be more abundant in the more saline western Baltic.

New marine ornamental species: the potential of Moon jellyfish Aurelia aurita

New marine ornamental species: the potential of Moon jellyfish Aurelia aurita

Symmetrization in jellyfish: reorganization to regain function, and not lost parts

We recently reported a previously unidentified strategy of self-repair in the moon jellyfish Aurelia aurita. Rather than regenerating lost parts, juvenile Aurelia reorganize remaining parts to regain essential body symmetry. This process that we called symmetrization is rapid and frequent, and is not driven by cell proliferation or cell death. Instead, the swimming machinery generates mechanical forces that drive symmetrization. We found evidence for symmetrization across three other species of jellyfish (Chrysaora pacifica, Mastigias sp., and Cotylorhiza tuberculata). We propose reorganization to regain function without recovery of initial morphology as a potentially broad class of self-repair strategy beyond radially symmetrical animals, and discuss the implications of this finding on the evolution of self-repair strategies in animals.