1
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Semkiv I. War: Mentalization and Totalitarian State of Mind. J Anal Psychol 2024; 69:281-297. [PMID: 38500376 DOI: 10.1111/1468-5922.12987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 01/28/2024] [Indexed: 03/20/2024]
Abstract
For most residents of Europe, war is a new experience in which they find themselves both as witnesses and participants. In this paper the war in Ukraine serves as an illustration and case example. Like any unfamiliar experience, war elicits profound emotional responses which can be so overwhelming that an individual may be unable to fully process them and to create mental representations of the reality of war. When the psyche becomes entrapped in an unprocessed state, without the capacity to derive meaning from it, this results in the "fossilization" of the psyche akin to what McGinley and Segal describes as a totalitarian state of mind. Subjectivity and individual differences come under collective or personal attack, or both. This state of being prioritizes the needs of the collective psyche over the individual psyche. The image of Gorgon Medusa, who transformed living people into "fossilized" ones, is presented as a metaphor of total identification with the collective dimension. In contrast, the psyche can reveal a creative approach to resolving war-induced trauma. This is depicted in the concept of the Alchemical Stone and its creation, which symbolizes a harmonious connection between the external and internal realms, the subjective and objective experiences, and the real and the imaginal dimension.
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2
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Sokol BJ. Freud's interpretation in " Medusa's Head" and some alternative psychoanalytic implications of Ovid's Medusa. Int J Psychoanal 2024; 105:192-209. [PMID: 38655646 DOI: 10.1080/00207578.2023.2255888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2023] [Indexed: 04/26/2024]
Abstract
Freud's very brief 1922 paper on the beheading of Medusa by Perseus wisely concludes with a call for a further examination of the sources of the legend. A now widespread interpretation of this legend is based (often without acknowledgement) on an addition to traditions concerning Medusa made in Ovid's Metamorphoses. It is argued here that this Ovidian innovation has often been misinterpreted, and that a more careful reading of Metamorphoses supports neither a widely alleged exclusively vengeful portrayal of Medusa, nor Freud's portrayal of Medusa's decapitation as solely a pitiable and terrible symbol of castration. Instead, Ovid's complex treatments of myths involving Medusa, Minerva and Perseus present parallels with Kleinian insights into phantasy attacks on fecundity, and into imagined revivals of dead or damaged inside babies. Thus the "displacement upwards" of the fearful castrated maternal genital envisioned in Freud's "Medusa's Head" must stand beside a quite different "displacement upwards" of the life-giving maternal genital. Indeed, tradition holds that Medusa's beheading gives rise to the birth of vigorous twins. Together with allied details, this aligns Ovid's masterwork with theories that modify or displace the so-called "sexual phallic monism" that some believe taints Freud's theories of gender development.
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Affiliation(s)
- B J Sokol
- Professor Emeritus, The University of London, London, UK
- Honorary Senior Research Fellow, University College London, London, UK
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3
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Ge J, Li B, Liao M, Zhang Z, Chen S, Xia B, Wang Y. Ingestion, egestion and physiological effects of polystyrene microplastics on the marine jellyfish Rhopilema esculentum. Mar Pollut Bull 2023; 187:114609. [PMID: 36652861 DOI: 10.1016/j.marpolbul.2023.114609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
Jellyfish are planktonic predators that may be susceptible to ingesting microplastics. However, the effects of MP exposure on jellyfish are poorly understood. In this study, the ingestion and egestion of polystyrene microbeads, and its chronic physiological effects on Rhopilema esculentum at an environmental concentration (100 items/L) and a predicted concentration (1000 items/L) were evaluated. The results showed that the ingestion amount of juvenile medusae was relatively low. The MP egestion rates reached 100 % within 9 h of clearance. Chronic exposure (15 days) to MPs at environmental concentrations led to no adverse impacts. Nevertheless, the predicted concentration of MP exposure induced growth inhibition, a reduction in assimilation efficiency, oxygen consumption increase, and lipase enzyme activity reduction in the jellyfish, indicating that MPs can cause adverse effects on the energy budget of jellyfish in the near future. Our study provides new insights into the potential risk of MPs in marine environments.
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Affiliation(s)
- Jianlong Ge
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Bin Li
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Meijie Liao
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Zheng Zhang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Siqing Chen
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Bin Xia
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China.
| | - Yingeng Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China.
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4
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Calland R. Facilitating the emergence of hidden dissociative identity disorder: finding the lost maiden Medusa. J Anal Psychol 2022; 67:73-87. [PMID: 35417571 DOI: 10.1111/1468-5922.12750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This paper uses the myth of Medusa as a containing narrative to explore the aetiology, recognition and treatment of emergent dissociative identity disorder or DID, in apparently high-functioning people. Both the 'hiding' nature of DID, and disbelief in therapists are identified as impediments to recognition of the disorder, despite the high prevalence of DID. The paper describes the impact on psycho-neurobiological development of both disorganized attachment and group sexual abuse at a young age, both typically present for DID survivors, leading to multiple ego centres in the psyche. DID is perceived as a creative protective mechanism against knowing, that also seals the abuse survivor into a lifetime of fractured self-experience, and exile from relational depth with others. Two case studies illuminate a key feature of DID, the existence of lost but ever-present child selves/alters, and how these may present within the therapeutic relationship. The author supports the facilitation by the analyst of self-diagnosis and describes how careful attunement to inner turmoil and confusion, can act as a containing mirror within which to discern the individual needs of a multiplicity of selves/alters, leading to increased self-agency, internal co-consciousness and the ability to function more authentically with others.
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Houliston E, Leclère L, Munro C, Copley RR, Momose T. Past, present and future of Clytia hemisphaerica as a laboratory jellyfish. Curr Top Dev Biol 2022; 147:121-151. [PMID: 35337447 DOI: 10.1016/bs.ctdb.2021.12.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The hydrozoan species Clytia hemisphaerica was selected in the mid-2000s to address the cellular and molecular basis of body axis specification in a cnidarian, providing a reliable daily source of gametes and building on a rich foundation of experimental embryology. The many practical advantages of this species include genetic uniformity of laboratory jellyfish, derived clonally from easily-propagated polyp colonies. Phylogenetic distance from other laboratory models adds value in providing an evolutionary perspective on many biological questions. Here we outline the current state of the art regarding available experimental approaches and in silico resources, and illustrate the contributions of Clytia to understanding embryo patterning mechanisms, oogenesis and regeneration. Looking forward, the recent establishment of transgenesis methods is now allowing gene function and imaging studies at adult stages, making Clytia particularly attractive for whole organism biology studies across fields and extending its scientific impact far beyond the original question of interest.
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Affiliation(s)
- Evelyn Houliston
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), France.
| | - Lucas Leclère
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), France
| | - Catriona Munro
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), France; Center for Interdisciplinary Research in Biology, Collège de France, PSL Research University, Paris, France
| | - Richard R Copley
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), France
| | - Tsuyoshi Momose
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), France
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6
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Lawley JW, Gamero-Mora E, Maronna MM, Chiaverano LM, Stampar SN, Hopcroft RR, Collins AG, Morandini AC. The importance of molecular characters when morphological variability hinders diagnosability: systematics of the moon jellyfish genus Aurelia (Cnidaria: Scyphozoa). PeerJ 2021; 9:e11954. [PMID: 34589293 PMCID: PMC8435205 DOI: 10.7717/peerj.11954] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 07/21/2021] [Indexed: 11/20/2022] Open
Abstract
Cryptic species have been detected across Metazoa, and while no apparent morphological features distinguish them, it should not impede taxonomists from formal descriptions. We accepted this challenge for the jellyfish genus Aurelia, which has a long and confusing taxonomic history. We demonstrate that morphological variability in Aurelia medusae overlaps across very distant geographic localities. Even though some morphological features seem responsible for most of the variation, regional geographic patterns of dissimilarities are lacking. This is further emphasized by morphological differences found when comparing lab-cultured Aurelia coerulea medusae with the diagnostic features in its recent redescription. Previous studies have also highlighted the difficulties in distinguishing Aurelia polyps and ephyrae, and their morphological plasticity. Therefore, mostly based on genetic data, we recognize 28 species of Aurelia, of which seven were already described, 10 are formally described herein, four are resurrected and seven remain undescribed. We present diagnostic genetic characters for all species and designate type materials for newly described and some resurrected species. Recognizing moon jellyfish diversity with formal names is vital for conservation efforts and other studies. This work clarifies the practical implications of molecular genetic data as diagnostic characters, and sheds light on the patterns and processes that generate crypsis.
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Affiliation(s)
- Jonathan W. Lawley
- Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
- School of Environment and Science, Coastal and Marine Research Centre, Australian Rivers Institute, Griffith University, Gold Coast, Queensland, Australia
| | - Edgar Gamero-Mora
- Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Maximiliano M. Maronna
- Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Luciano M. Chiaverano
- Instituto Nacional de Investigación y Desarrollo Pesquero, Mar del Plata, Buenos Aires, Argentina
| | - Sérgio N. Stampar
- Departamento de Ciências Biológicas, Faculdade de Ciências e Letras, Universidade Estadual Paulista, Assis, São Paulo, Brazil
| | - Russell R. Hopcroft
- College of Fisheries and Ocean Sciences, University of Alaska—Fairbanks, Fairbanks, Alaska, United States
| | - Allen G. Collins
- National Systematics Laboratory of the National Oceanic and Atmospheric Administration Fisheries Service, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, United States
| | - André C. Morandini
- Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
- Centro de Biologia Marinha, Universidade de São Paulo, São Sebastião, São Paulo, Brazil
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7
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Loveridge A, Pitt KA, Lucas CH, Warnken J. Extreme changes in salinity drive population dynamics of Catostylus mosaicus medusae in a modified estuary. Mar Environ Res 2021; 168:105306. [PMID: 33839400 DOI: 10.1016/j.marenvres.2021.105306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/02/2021] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
Modifications to estuaries through the construction of barrages alter the natural dynamics of inhabitant species by controlling freshwater inputs into those systems. To understand the effects of modified freshwater flows on a native scyphozoan jellyfish, Catostylus mosaicus, and to identify the environmental drivers of medusa occurrence, we analysed a 20-year observational dataset composed of 11 environmental variables and medusa presence/absence from 15 sampling stations located below the Fitzroy Barrage, in the Fitzroy River, Queensland. Major decreases in salinity (minimum salinity 0) occurred approximately 16 times during the 20-year period and medusae disappeared from the estuary following every major freshwater flow event. Salinity was identified as the most influential variable contributing to variation in the number of upper estuary sites reporting jellyfish. We then ran two laboratory experiments to test the following hypotheses: (i) prolonged decreases in salinity impair survival, pulsation, and respiration rates of C. mosaicus medusae; and (ii) transient decreases temporarily impair pulsation and respiration but medusae recover when salinity returns to normal levels. Medusae were unable to survive extended periods at extreme low salinities, such that they would experience when a barrage opens fully, but had significantly higher survival and recovery rates following smaller, transient changes to salinity that might occur following a moderate rainfall event. This demonstrates for the first time that modification of freshwater flow by a barrage regulates the population dynamics of an estuarine jellyfish, and highlights the need for robust, long term datasets, and to firmly embed experimental approaches in realistic ecological contexts.
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Affiliation(s)
- Alexandra Loveridge
- Ocean and Earth Science, University of Southampton, Southampton, United Kingdom.
| | - Kylie A Pitt
- Australian Rivers Institute - Coasts and Estuaries, Griffith School of Environment and Science, Griffith University, Gold Coast, QLD, Australia
| | - Cathy H Lucas
- Ocean and Earth Science, University of Southampton, Southampton, United Kingdom
| | - Jan Warnken
- Australian Rivers Institute - Coasts and Estuaries, Griffith School of Environment and Science, Griffith University, Gold Coast, QLD, Australia
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8
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Muffett K, Miglietta MP. Planktonic associations between medusae (classes Scyphozoa and Hydrozoa) and epifaunal crustaceans. PeerJ 2021; 9:e11281. [PMID: 33981503 PMCID: PMC8074843 DOI: 10.7717/peerj.11281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/24/2021] [Indexed: 12/31/2022] Open
Abstract
Jellyfish are known to carry various epibionts, including many of the subphylum Crustacea. However, the associations between gelatinous zooplankton and other invertebrates have been chronically overlooked. Crustacea, a massive clade of economically, ecologically, and culturally important species, includes many taxa that utilize gelatinous zooplankton for food, transport, and protection as both adults and juveniles. Here we compile 211 instances of epifaunal crustaceans recorded on Hydromedusae and Scyphomedusae from a century of literature. These include 78 identified crustacean species in 65 genera across nine orders found upon 37 Hydromedusa species and 48 Scyphomedusae. The crustacean life stage, location, nature of the association with the medusa, years, months, and depths are compiled to form a comprehensive view of the current state of the literature. Additionally, this review highlights areas where the current literature is lacking, particularly noting our poor understanding of the relationships between juvenile crabs of commercially valuable species and medusae.
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Affiliation(s)
- Kaden Muffett
- Department of Marine Biology, Texas A&M University - Galveston, Galveston, Texas, United States
| | - Maria Pia Miglietta
- Department of Marine Biology, Texas A&M University - Galveston, Galveston, Texas, United States
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9
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Rosell J, Montero E, Candelas M, Crespo-Picazo JL, García-Párraga D, LaDouceur EEB, Corpa JM, Ortega J. Pathological findings and husbandry management in captive Chrysaora spp. medusae affected by umbrellar ulcerative lesions. J Invertebr Pathol 2021; 183:107599. [PMID: 33957130 DOI: 10.1016/j.jip.2021.107599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/20/2021] [Accepted: 04/26/2021] [Indexed: 11/22/2022]
Abstract
During a 12 month period, a group of 14 medusa-stage jellies of the genus Chrysaora, including Pacific sea nettle (Chrysaora fuscescens, n = 11) and Japanese sea nettle (Chrysaora pacifica, n = 3), that were maintained in a public aquarium developed progressive ulcerative umbrellar lesions. In 6 cases (42.9%), ulceration was deep, transmural, and perforated through the mesoglea and subumbrella. In 6 cases (42.9%), ciliated protozoa histomorphologically consistent with scuticociliates were observed in the mesoglea and gastrovascular cavity. In 2 cases (14.3%), commensal dinoflagellates (zooxanthellae) were in the mesoglea and in the cytoplasm of the scuticociliates. During this period, water quality parameters including temperature [°C], pH, oxidation-reduction potential (ORP) [mV], salinity [psu], dissolved oxygen [%], ammonia (NH3), and nitrite(NO2) levels were monitored daily or weekly. The main water quality abnormalities were increased NO2 and pH levels above recommended reference ranges for C. fuscescens and elevated temperature above recommended reference ranges for C. pacifica tank. After correction of water quality parameters, apparent improvement of jellies was observed. In this case, environmental factors were considered the most likely predisposing factors for the development of ulcerative lesions, and ciliated protozoa were considered secondary rather than primary pathogens.
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10
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Gamero-Mora E, Halbauer R, Bartsch V, Stampar SN, Morandini AC. Regenerative Capacity of the Upside-down Jellyfish Cassiopea xamachana. Zool Stud 2019; 58:e37. [PMID: 31966338 PMCID: PMC6971530 DOI: 10.6620/zs.2019.58-37] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/30/2019] [Indexed: 12/28/2022]
Abstract
This study provides the first observation that umbrellar tissue can lead to the formation of virtually all body structures in jellyfish of the order Rhizostomeae. The regeneration process was observed in two specimens of the upside-down jellyfish Cassiopea xamachana Bigelow, 1892, one housed at the Vienna Zoo, Austria and the other in a laboratory at the University of São Paulo, Brazil. The process was triggered by an injury and ended with the formation of two new sets of body structures. Our observation offers evidence that C. xamachana has a hidden regenerative capacity exceeding that previously recorded.
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Affiliation(s)
- Edgar Gamero-Mora
- Departamento de Zoologia, Instituto Biociências,
Universidade de São Paulo, Rua do Matão, travessa 14, n. 101, Cidade Universitária,
São Paulo, SP, 05508-090, Brazil.
| | - Roland Halbauer
- Vienna Zoo, Maxingstraße 13b, 1130, Vienna, Austria.
E-mail: (Halbauer),
(Bartsch)
| | - Vanessa Bartsch
- Vienna Zoo, Maxingstraße 13b, 1130, Vienna, Austria.
E-mail: (Halbauer),
(Bartsch)
| | - Sérgio N. Stampar
- Departamento de Ciências Biológicas, Laboratório de
Evolução e Diversidade Aquática – LEDA, Universidade Estadual Paulista “Julio de
Mesquita Filho” (UNESP), FCL/Assis, Assis, SP, 19806-900, Brazil. E-mail:
| | - André C. Morandini
- Departamento de Zoologia, Instituto Biociências,
Universidade de São Paulo, Rua do Matão, travessa 14, n. 101, Cidade Universitária,
São Paulo, SP, 05508-090, Brazil.
- Centro de Biologia Marinha, Universidade de São Paulo,
Rod. Manuel Hypólito do Rego, km 131.5, São Sebastião, SP, 11600-000, Brazil. E-mail:
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11
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Pruski S, Miglietta MP. Fluctuation and diversity of Hydro medusae (Hydrozoa, Cnidaria) in a highly productive region of the Gulf of Mexico inferred from high frequency plankton sampling. PeerJ 2019; 7:e7848. [PMID: 31608180 PMCID: PMC6788443 DOI: 10.7717/peerj.7848] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 09/08/2019] [Indexed: 11/20/2022] Open
Abstract
Hydrozoa medusae undergo blooms and seasonal fluctuations; however the drivers of such fluctuations are unknown. To understand how medusa populations fluctuate in response to seasonal factors such as temperature, salinity, dissolved oxygen, and chlorophyll a, and to enhance our taxonomic knowledge of Hydrozoa in Galveston Bay (TX), we performed frequent plankton sampling from September 2015 to September 2016. We collected 1,321 medusae in 190 sampling days. Using molecular barcoding and morphological analyses we identified 25 species, of which 21 are a first record for Galveston Bay and eight for the Gulf of Mexico. Daily medusa abundance is non-linearly related to temperature, with peak abundance estimated with multivariate regression analysis at approximately 21C. The role that temperature plays in driving medusa abundance has implications for future climate change scenarios, given that temperature in the Gulf of Mexico is expected to rise 4 °C by the end of the century. We also show that the biodiversity of the Galveston Bay and the Gulf of Mexico is underestimated and that molecular barcoding is an important and efficient tool to identify large number of medusae. We conclude that dense plankton sampling is necessary to capture both diversity and abundance of planktonic medusae.
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Affiliation(s)
- Sarah Pruski
- Department of Marine Biology, Texas A&M University-Galveston, Galveston, TX, United States of America
| | - Maria Pia Miglietta
- Department of Marine Biology, Texas A&M University-Galveston, Galveston, TX, United States of America
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12
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Condamine T, Jager M, Leclère L, Blugeon C, Lemoine S, Copley RR, Manuel M. Molecular characterisation of a cellular conveyor belt in Clytia medusae. Dev Biol 2019; 456:212-225. [PMID: 31509769 DOI: 10.1016/j.ydbio.2019.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/29/2019] [Accepted: 09/07/2019] [Indexed: 11/25/2022]
Abstract
The tentacular system of Clytia hemisphaerica medusa (Cnidaria, Hydrozoa) has recently emerged as a promising experimental model to tackle the developmental mechanisms that regulate cell lineage progression in an early-diverging animal phylum. From a population of proximal stem cells, the successive steps of tentacle stinging cell (nematocyte) elaboration, are spatially ordered along a "cellular conveyor belt". Furthermore, the C. hemisphaerica tentacular system exhibits bilateral organisation, with two perpendicular polarity axes (proximo-distal and oral-aboral). We aimed to improve our knowledge of this cellular system by combining RNAseq-based differential gene expression analyses and expression studies of Wnt signalling genes. RNAseq comparisons of gene expression levels were performed (i) between the tentacular system and a control medusa deprived of all tentacles, nematogenic sites and gonads, and (ii) between three samples staggered along the cellular conveyor belt. The behaviour in these differential expression analyses of two reference gene sets (stem cell genes; nematocyte genes), as well as the relative representations of selected gene ontology categories, support the validity of the cellular conveyor belt model. Expression patterns obtained by in situ hybridisation for selected highly differentially expressed genes and for Wnt signalling genes are largely consistent with the results from RNAseq. Wnt signalling genes exhibit complex spatial deployment along both polarity axes of the tentacular system, with the Wnt/β-catenin pathway probably acting along the oral-aboral axis rather than the proximo-distal axis. These findings reinforce the idea that, despite overall radial symmetry, cnidarians have a full potential for elaboration of bilateral structures based on finely orchestrated deployment of an ancient developmental gene toolkit.
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Affiliation(s)
- Thomas Condamine
- Sorbonne Université, MNHN, CNRS, EPHE, Institut de Systématique, Evolution, Biodiversité (ISYEB UMR 7205), Paris, France
| | - Muriel Jager
- Sorbonne Université, MNHN, CNRS, EPHE, Institut de Systématique, Evolution, Biodiversité (ISYEB UMR 7205), Paris, France
| | - Lucas Leclère
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, 181 chemin du Lazaret, 06230, Villefranche-sur-mer, France
| | - Corinne Blugeon
- Genomic Paris Centre, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Sophie Lemoine
- Genomic Paris Centre, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Richard R Copley
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, 181 chemin du Lazaret, 06230, Villefranche-sur-mer, France
| | - Michaël Manuel
- Sorbonne Université, MNHN, CNRS, EPHE, Institut de Systématique, Evolution, Biodiversité (ISYEB UMR 7205), Paris, France.
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13
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Neil TR, Askew GN. Jet-paddling jellies: swimming performance in the Rhizostomeae jellyfish Catostylus mosaicus. ACTA ACUST UNITED AC 2018; 221:jeb.191148. [PMID: 30348647 DOI: 10.1242/jeb.191148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 10/14/2018] [Indexed: 11/20/2022]
Abstract
Jellyfish are a successful and diverse class of animals that swim via jet propulsion, with swimming performance and propulsive efficiency being related to the animal's feeding ecology and body morphology. The Rhizostomeae jellyfish lack tentacles but possess four oral lobes and eight trailing arms at the centre of their bell, giving them a body morphology quite unlike that of other free-swimming medusae. The implications of this body morphology on the mechanisms by which thrust is produced are unknown. Here, we determined the wake structure and propulsive efficiency in the blue-blubber jellyfish Catostylus mosaicus (order: Rhizostomeae). The animal is propelled during both bell contraction and bell relaxation by different thrust-generating mechanisms. During bell contraction, a jet of fluid is expelled from the subumbrellar cavity, which results from the interaction between the counter-rotating stopping (from the preceding contraction cycle) and starting vortices, creating a vortex superstructure and propulsion. This species is also able to utilise passive energy recapture, which increases the animal's swimming velocity towards the end of the bell expansion phase when the bell diameter is constant. The thrust produced during this phase is the result of the flexible bell margin manoeuvring the stopping vortex into the subumbrellar cavity during bell relaxation, enhancing its circulation, and creating a region of high pressure on the inner surface of the bell and, consequently, thrust. These mechanisms of thrust generation result in C. mosaicus having a relatively high propulsive efficiency compared with other swimmers, indicating that economical locomotion could be a contributing factor in the ecological success of these medusan swimmers.
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Affiliation(s)
- Thomas R Neil
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Graham N Askew
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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Li JY, Guo DH, Wu PC, He LS. Ontogeny reversal and phylogenetic analysis of Turritopsis sp.5 (Cnidaria, Hydrozoa, Oceaniidae), a possible new species endemic to Xiamen, China. PeerJ 2018; 6:e4225. [PMID: 29333345 PMCID: PMC5764029 DOI: 10.7717/peerj.4225] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 12/13/2017] [Indexed: 11/20/2022] Open
Abstract
Ontogeny reversal, as seen in some cnidarians, is an unprecedented phenomenon in the animal kingdom involving reversal of the ordinary life cycle. Three species of Turritopsis have been shown to be capable of inverted metamorphosis, a process in which the pelagic medusa transforms back into a juvenile benthic polyp stage when faced with adverse conditions. Turritopsis sp.5 is a species of Turritopsis collected from Xiamen, China which presents a similar ability, being able to reverse its life cycle if injured by mechanical stress. Phylogenetic analysis based on both 16S rDNA and cytochrome c oxidase subunit I (COI) genetic barcodes shows that Turritopsis sp.5 is phylogenetically clustered in a clade separate from other species of Turritopsis. The genetic distance between T. sp.5 and the Japanese species T. sp.2 is the shortest, when measured by the Kimura 2-Parameter metric, and the distance to the New Zealand species T. rubra is the largest. An experimental assay on the induction of reverse development in this species was initiated by cutting medusae into upper and lower parts. We show, for the first time, that the two dissected parts have significantly different potentials to transform into polyps. Also, a series of morphological changes of the reversed life cycle can be recognised, including medusa stage, contraction stage I, contraction stage II, cyst, cyst with stolons, and polyp. The discovery of species capable of reverse ontogeny caused by unfavorable conditions adds to the available systems with which to study the cell types that contribute to the developmental reversal and the molecular mechanisms of the directional determination of ontogeny.
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Affiliation(s)
- Jun-Yuan Li
- Department of Life Sciences, Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, China.,College of Earth Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Dong-Hui Guo
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian, China
| | - Peng-Cheng Wu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian, China
| | - Li-Sheng He
- Department of Life Sciences, Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, China
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