Prevalence and photobiology of photosynthetic endosymbionts of Exaiptasia diaphana in Berghia stephanieae

Detalhes bibliográficos
Autor(a) principal: Silva, Ruben Xavier Grave da
Data de Publicação: 2021
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10773/30750
Resumo: Nudibranchs are soft bodied, shell-less marine gastropod molluscs. They are widespread over a wide variety of environments. Some of these species are known due to their stenophagous dietary habits and their ability to retain photosynthetic endosymbionts from their preys. One of such nudibranchs is the aelolid Berghia stephanieae, a stenophagous nudibranch that retains both the photosynthetic endosymbionts and the nematocysts of its prey, the glass anemone Exaiptasia diaphana. Berghia stephanieae is known to be one of the best models for ecological studies addressing the mollusc-photosynthetic dinoflagellate endosymbiosis. However, these studies are often made with the use of invasive techniques, that commonly harm the study subject, and may even lead to their sacrifice. The glass anemone, E. diaphana, is seen as a model species to the study of cnidarian-microbiome symbiosis. As this species establishes a symbiosis with photosynthetic dinoflagellates, it has been used to study bleaching, the phenomenon that results from the loss of photosynthetic endosymbionts or pigments from the animal host. The present work addresses the maintenance of the symbiosis between B. stephanieae and its photosynthetic dinoflagellate endosymbionts acquired through the predation of E. diaphana using a non-invasive methodology, the measurement of pulse amplitude modulated chlorophyll fluorescence. While this methodology is commonly employed on plants and algae, it has already been successfully used to study kleptoplasty in sacoglossan sea slugs, as well as the maintenance of photosynthetic efficiency of photosynthetic dinoflagellate endosymbionts in some nudibranchs. Our experimental trials made possible to detect a positive correlation between the abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and the minimum fluorescence of dark-adapted animals (F₀). The abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and their photosynthetic efficiency were studied in sea slugs reared under different light intensities (high light, 80 µmol m- ² s - ¹; low light, 10 µmol m- ² s - ¹) and access to food. Exposure to different light intensities had no significant impact in the maintenance of B. stephanieae’s photosynthetic dinoflagellate endosymbionts, nor on their photosynthetic efficiency. However, starvation was shown to have a significant impact by decreasing both the abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and their photosynthetic efficiency. The effect of different trophic regimes in the abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and their photosynthetic efficiency was also tested. It was possible to show that sea slugs fed with bleached anemones (anemones lacking photosynthetic dinoflagellate endosymbionts) were impacted in a similar way to starved sea slugs, as they both exhibited a decrease in the abundance of photosynthetic dinoflagellate endosymbionts and a lower photosynthetic efficiency. This finding shows that the photosynthetic dinoflagellate endosymbionts present within B. stephanieae need to be replenished regularly by these nudibranchs by preying on symbiotic glass anemones (anemones that have photosynthetic dinoflagellate endosymbionts). Overall, the present study is the starting point to future works on which chlorophyll fluorescence parameter F₀ may be used to infer the abundance, maintenance and photosynthetic efficiency of endosymbionts in nudibranchs. This methodology may be a powerful tool to study the consequences of bleaching of marine organisms on their stenophagous predators, as these are widely unknown and need to be further investigated.
id RCAP_1bcf2bca7926aa45c025ff23deea6aec
oai_identifier_str oai:ria.ua.pt:10773/30750
network_acronym_str RCAP
network_name_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository_id_str 7160
spelling Prevalence and photobiology of photosynthetic endosymbionts of Exaiptasia diaphana in Berghia stephanieaeEndosymbiotic photosynthetic dynoflagellatesStenophagous speciesPhotobiologyBleachingNudibranchs are soft bodied, shell-less marine gastropod molluscs. They are widespread over a wide variety of environments. Some of these species are known due to their stenophagous dietary habits and their ability to retain photosynthetic endosymbionts from their preys. One of such nudibranchs is the aelolid Berghia stephanieae, a stenophagous nudibranch that retains both the photosynthetic endosymbionts and the nematocysts of its prey, the glass anemone Exaiptasia diaphana. Berghia stephanieae is known to be one of the best models for ecological studies addressing the mollusc-photosynthetic dinoflagellate endosymbiosis. However, these studies are often made with the use of invasive techniques, that commonly harm the study subject, and may even lead to their sacrifice. The glass anemone, E. diaphana, is seen as a model species to the study of cnidarian-microbiome symbiosis. As this species establishes a symbiosis with photosynthetic dinoflagellates, it has been used to study bleaching, the phenomenon that results from the loss of photosynthetic endosymbionts or pigments from the animal host. The present work addresses the maintenance of the symbiosis between B. stephanieae and its photosynthetic dinoflagellate endosymbionts acquired through the predation of E. diaphana using a non-invasive methodology, the measurement of pulse amplitude modulated chlorophyll fluorescence. While this methodology is commonly employed on plants and algae, it has already been successfully used to study kleptoplasty in sacoglossan sea slugs, as well as the maintenance of photosynthetic efficiency of photosynthetic dinoflagellate endosymbionts in some nudibranchs. Our experimental trials made possible to detect a positive correlation between the abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and the minimum fluorescence of dark-adapted animals (F₀). The abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and their photosynthetic efficiency were studied in sea slugs reared under different light intensities (high light, 80 µmol m- ² s - ¹; low light, 10 µmol m- ² s - ¹) and access to food. Exposure to different light intensities had no significant impact in the maintenance of B. stephanieae’s photosynthetic dinoflagellate endosymbionts, nor on their photosynthetic efficiency. However, starvation was shown to have a significant impact by decreasing both the abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and their photosynthetic efficiency. The effect of different trophic regimes in the abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and their photosynthetic efficiency was also tested. It was possible to show that sea slugs fed with bleached anemones (anemones lacking photosynthetic dinoflagellate endosymbionts) were impacted in a similar way to starved sea slugs, as they both exhibited a decrease in the abundance of photosynthetic dinoflagellate endosymbionts and a lower photosynthetic efficiency. This finding shows that the photosynthetic dinoflagellate endosymbionts present within B. stephanieae need to be replenished regularly by these nudibranchs by preying on symbiotic glass anemones (anemones that have photosynthetic dinoflagellate endosymbionts). Overall, the present study is the starting point to future works on which chlorophyll fluorescence parameter F₀ may be used to infer the abundance, maintenance and photosynthetic efficiency of endosymbionts in nudibranchs. This methodology may be a powerful tool to study the consequences of bleaching of marine organisms on their stenophagous predators, as these are widely unknown and need to be further investigated.Os nudibrânquios são moluscos gastrópodes marinhos de corpo mole, sem concha, que ocorrem numa grande variedade de ambientes. Algumas destas espécies são conhecidas pelos seus hábitos alimentares estenófagos e por reterem endossimbiontes fotossintéticos presentes nas presas das quais se alimentam. Uma dessas espécies é o aeolídeo Berghia stephanieae, um nudibrânquio estenófago que retém os dinoflagelados endossimbiontes fotossintéticos e os nematocistos da sua presa, a anémona de vidro Exaiptasia diaphana. Berghia stephanieae é considerada uma espécie modelo para estudos ecológicos referentes à endossimbiose entre moluscos e dinoflagelados fotossintéticos. No entanto, estes estudos são frequentemente realizados com recurso a metodologias invasivas, que invariavelmente causam danos físicos aos organismos em estudo, ou podem mesmo levar ao seu sacrifício. A anémona de vidro, E. diaphana, é considerada uma espécie modelo para o estudo da simbiose entre os cnidários e os seus microbiomas. Devido à sua simbiose com dinoflagelados fotossintéticos, esta espécie tem sido utilizada para estudar o fenómeno de branqueamento, fenómeno resultante da perda de simbiontes ou pigmentos fotossintéticos presentes num animal hospedeiro. O presente trabalho estuda a prevalência da associação entre B. stephanieae e os dinoflagelados endossimbiontes fotossintéticos obtidos troficamente pela ingestão de E. diaphana através da utilização de uma metodologia não invasiva, a medição da fluorescência de pulso modelado da clorofila. Esta metodologia é utilizada de forma rotineira em plantas e algas, tendo, no entanto, já sido utilizada com sucesso para o estudo da cleptoplastia em lesmas marinhas da superordem Sacoglossa. Esta metodologia foi também já utilizada para estudar a manutenção da eficiência fotossintética de dinoflagelados endossimbiontes fotossintéticos presentes nalgumas espécies de nudibrânquios. Através da sua utilização foi possível identificar uma correlação positiva entre a abundância de dinoflagelados endossimbiontes fotossintéticos presentes em B. stephanieae e a fluorescência mínima de animais adaptados ao escuro (F₀). A abundância de dinoflagelados endossimbiontes fotossintéticos presentes em B. stephanieae e a sua eficiência fotossintética foram estudadas em lesmas marinhas com e sem acesso a fonte de alimento e criadas a diferentes intensidades de luz (luz alta, 80 µmol m- ² s - ¹; luz baixa, 10 µmol m- ² s - ¹). A exposição a diferentes intensidades de luz não teve efeitos na manutenção da eficiência fotossintética ou na abundância dos endossimbiontes fotossintéticos presentes em B. stephanieae. No entanto, a exposição à inanição teve um impacto significativo, fazendo decrescer tanto a abundância dos dinoflagelados endossimbiontes fotossintéticos presentes em B. stephanieae, tal como a sua eficiência fotossintética. Foi também testado o efeito de diferentes regimes tróficos na abundância de dinoflagelados endossimbiontes fotossintéticos presentes em B. stephanieae e a sua eficiência fotossintética. Este estudo permitiu evidenciar que indivíduos alimentados com anémonas branqueadas (anémonas sem dinoflagelados endossimbiontes fotossintéticos) apresentavam um impacto semelhante ao verificado em conspecíficos sujeitos a inanição, ou seja, um decréscimo na abundância de endossimbiontes fotossintéticos, assim como da sua eficiência fotossintética. Estes resultados mostram que os dinoflagelados endossimbiontes fotossintéticos presentes em B. stephanieae necessitam de ser repostos regularmente por estes nudibrânquios através da predação de anémonas vidro que apresentem estes endossimbiontes fotossintéticos. Este estudo serve de ponto de partida para trabalhos futuros nos quais o parâmetro de fluorescência da clorofila F₀ poderá ser usado para inferir a abundância, manutenção e eficiência fotossintética de endossimbiontes fotossintéticos em nudibrânquios, assim como a manutenção da sua simbiose. Esta metodologia pode ser uma ferramenta valiosa para o estudo das consequências do branqueamento de organismos marinhos nos seus predadores estenófagos, consequências essas que são pouco conhecidas e, como tal, carecem de investigação.2022-02-19T00:00:00Z2021-02-08T00:00:00Z2021-02-08info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10773/30750engSilva, Ruben Xavier Grave dainfo:eu-repo/semantics/embargoedAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-02-22T11:59:23Zoai:ria.ua.pt:10773/30750Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:02:45.654485Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Prevalence and photobiology of photosynthetic endosymbionts of Exaiptasia diaphana in Berghia stephanieae
title Prevalence and photobiology of photosynthetic endosymbionts of Exaiptasia diaphana in Berghia stephanieae
spellingShingle Prevalence and photobiology of photosynthetic endosymbionts of Exaiptasia diaphana in Berghia stephanieae
Silva, Ruben Xavier Grave da
Endosymbiotic photosynthetic dynoflagellates
Stenophagous species
Photobiology
Bleaching
title_short Prevalence and photobiology of photosynthetic endosymbionts of Exaiptasia diaphana in Berghia stephanieae
title_full Prevalence and photobiology of photosynthetic endosymbionts of Exaiptasia diaphana in Berghia stephanieae
title_fullStr Prevalence and photobiology of photosynthetic endosymbionts of Exaiptasia diaphana in Berghia stephanieae
title_full_unstemmed Prevalence and photobiology of photosynthetic endosymbionts of Exaiptasia diaphana in Berghia stephanieae
title_sort Prevalence and photobiology of photosynthetic endosymbionts of Exaiptasia diaphana in Berghia stephanieae
author Silva, Ruben Xavier Grave da
author_facet Silva, Ruben Xavier Grave da
author_role author
dc.contributor.author.fl_str_mv Silva, Ruben Xavier Grave da
dc.subject.por.fl_str_mv Endosymbiotic photosynthetic dynoflagellates
Stenophagous species
Photobiology
Bleaching
topic Endosymbiotic photosynthetic dynoflagellates
Stenophagous species
Photobiology
Bleaching
description Nudibranchs are soft bodied, shell-less marine gastropod molluscs. They are widespread over a wide variety of environments. Some of these species are known due to their stenophagous dietary habits and their ability to retain photosynthetic endosymbionts from their preys. One of such nudibranchs is the aelolid Berghia stephanieae, a stenophagous nudibranch that retains both the photosynthetic endosymbionts and the nematocysts of its prey, the glass anemone Exaiptasia diaphana. Berghia stephanieae is known to be one of the best models for ecological studies addressing the mollusc-photosynthetic dinoflagellate endosymbiosis. However, these studies are often made with the use of invasive techniques, that commonly harm the study subject, and may even lead to their sacrifice. The glass anemone, E. diaphana, is seen as a model species to the study of cnidarian-microbiome symbiosis. As this species establishes a symbiosis with photosynthetic dinoflagellates, it has been used to study bleaching, the phenomenon that results from the loss of photosynthetic endosymbionts or pigments from the animal host. The present work addresses the maintenance of the symbiosis between B. stephanieae and its photosynthetic dinoflagellate endosymbionts acquired through the predation of E. diaphana using a non-invasive methodology, the measurement of pulse amplitude modulated chlorophyll fluorescence. While this methodology is commonly employed on plants and algae, it has already been successfully used to study kleptoplasty in sacoglossan sea slugs, as well as the maintenance of photosynthetic efficiency of photosynthetic dinoflagellate endosymbionts in some nudibranchs. Our experimental trials made possible to detect a positive correlation between the abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and the minimum fluorescence of dark-adapted animals (F₀). The abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and their photosynthetic efficiency were studied in sea slugs reared under different light intensities (high light, 80 µmol m- ² s - ¹; low light, 10 µmol m- ² s - ¹) and access to food. Exposure to different light intensities had no significant impact in the maintenance of B. stephanieae’s photosynthetic dinoflagellate endosymbionts, nor on their photosynthetic efficiency. However, starvation was shown to have a significant impact by decreasing both the abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and their photosynthetic efficiency. The effect of different trophic regimes in the abundance of photosynthetic dinoflagellate endosymbionts within B. stephanieae and their photosynthetic efficiency was also tested. It was possible to show that sea slugs fed with bleached anemones (anemones lacking photosynthetic dinoflagellate endosymbionts) were impacted in a similar way to starved sea slugs, as they both exhibited a decrease in the abundance of photosynthetic dinoflagellate endosymbionts and a lower photosynthetic efficiency. This finding shows that the photosynthetic dinoflagellate endosymbionts present within B. stephanieae need to be replenished regularly by these nudibranchs by preying on symbiotic glass anemones (anemones that have photosynthetic dinoflagellate endosymbionts). Overall, the present study is the starting point to future works on which chlorophyll fluorescence parameter F₀ may be used to infer the abundance, maintenance and photosynthetic efficiency of endosymbionts in nudibranchs. This methodology may be a powerful tool to study the consequences of bleaching of marine organisms on their stenophagous predators, as these are widely unknown and need to be further investigated.
publishDate 2021
dc.date.none.fl_str_mv 2021-02-08T00:00:00Z
2021-02-08
2022-02-19T00:00:00Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10773/30750
url http://hdl.handle.net/10773/30750
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/embargoedAccess
eu_rights_str_mv embargoedAccess
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron:RCAAP
instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
institution RCAAP
reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
collection Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
repository.mail.fl_str_mv
_version_ 1799137683069468672