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Elise Biquand, Nami Okubo, Yusuke Aihara, Vivien Rolland, David C Hayward, Masayuki Hatta, Jun Minagawa, Tadashi Maruyama, Shunichi Takahashi
Reef-building corals form symbiotic relationships with dinoflagellates of the genus Symbiodinium. Symbiodinium are genetically and physiologically diverse, and corals may be able to adapt to different environments by altering their dominant Symbiodinium phylotype. Notably, each coral species associates only with specific Symbiodinium phylotypes, and consequently the diversity of symbionts available to the host is limited by the species specificity. Currently, it is widely presumed that species specificity is determined by the combination of cell-surface molecules on the host and symbiont...
March 21, 2017: ISME Journal
Katie E Hillyer, Daniel A Dias, Adrian Lutz, Ute Roessner, Simon K Davy
Coral bleaching is a major threat to the persistence of coral reefs. Yet we lack detailed knowledge of the metabolic interactions that determine symbiosis function and bleaching-induced change. We mapped autotrophic carbon fate within the free metabolite pools of both partners of a model cnidarian-dinoflagellate symbiosis (Aiptasia-Symbiodinium) during exposure to thermal stress via the stable isotope tracer ((13) C bicarbonate), coupled to GC-MS. Symbiont photodamage and pronounced bleaching coincided with substantial increases in the turnover of non(13) C-labelled pools in the dinoflagellate (lipid and starch store catabolism)...
March 8, 2017: New Phytologist
Sheila A Kitchen, Virginia M Weis
Sphingolipids play important roles in mitigating cellular heat and oxidative stress by altering membrane fluidity, receptor clustering and gene expression. Accumulation of signaling sphingolipids that comprise the sphingosine rheostat, pro-apoptotic sphingosine (Sph) and pro-survival sphingosine-1-phosphate (S1P), is key to determining cell fate. Reef-building corals and other symbiotic cnidarians living in shallow tropical waters can experience elevated seawater temperature and high UV irradiance, two stressors that are increasing in frequency and severity with climate change...
February 22, 2017: Journal of Experimental Biology
Judith F Carlisle, Grant K Murphy, Alison M Roark
Pale anemones (Aiptasia pallida) coexist with dinoflagellates (primarily Symbiodinium minutum) in a mutualistic relationship. The purpose of this study was to investigate the role of these symbionts in gonad development of anemone hosts. Symbiotic and aposymbiotic anemones were subjected to light cycles that induced gametogenesis. These anemones were then sampled weekly for nine weeks, and gonad development was analyzed histologically. Anemone size was measured as mean body column diameter, and oocytes or sperm follicles were counted for each anemone...
2017: Symbiosis
Emilie F Neubauer, Angela Z Poole, Virginia M Weis, Simon K Davy
Many cnidarians engage in a mutualism with endosymbiotic photosynthetic dinoflagellates that forms the basis of the coral reef ecosystem. Interpartner interaction and regulation includes involvement of the host innate immune system. Basal metazoans, including cnidarians have diverse and complex innate immune repertoires that are just beginning to be described. Scavenger receptors (SR) are a diverse superfamily of innate immunity genes that recognize a broad array of microbial ligands and participate in phagocytosis of invading microbes...
2016: PeerJ
Iliona Wolfowicz, Sebastian Baumgarten, Philipp A Voss, Elizabeth A Hambleton, Christian R Voolstra, Masayuki Hatta, Annika Guse
Symbiosis, defined as the persistent association between two distinct species, is an evolutionary and ecologically critical phenomenon facilitating survival of both partners in diverse habitats. The biodiversity of coral reef ecosystems depends on a functional symbiosis with photosynthetic dinoflagellates of the highly diverse genus Symbiodinium, which reside in coral host cells and continuously support their nutrition. The mechanisms underlying symbiont selection to establish a stable endosymbiosis in non-symbiotic juvenile corals are unclear...
2016: Scientific Reports
Angela Z Poole, Sheila A Kitchen, Virginia M Weis
The complement system is an innate immune pathway that in vertebrates, is responsible for initial recognition and ultimately phagocytosis and destruction of microbes. Several complement molecules including C3, Factor B, and mannose binding lectin associated serine proteases (MASP) have been characterized in invertebrates and while most studies have focused on their conserved role in defense against pathogens, little is known about their role in managing beneficial microbes. The purpose of this study was to (1) characterize complement pathway genes in the symbiotic sea anemone Aiptasia pallida, (2) investigate the evolution of complement genes in invertebrates, and (3) examine the potential dual role of complement genes Factor B and MASP in the onset and maintenance of cnidarian-dinoflagellate symbiosis and immune challenge using qPCR based studies...
2016: Frontiers in Microbiology
Tamaki Bieri, Masayuki Onishi, Tingting Xiang, Arthur R Grossman, John R Pringle
When exposed to stress such as high seawater temperature, corals and other cnidarians can bleach due to loss of symbiotic algae from the host tissue and/or loss of pigments from the algae. Although the environmental conditions that trigger bleaching are reasonably well known, its cellular and molecular mechanisms are not well understood. Previous studies have reported the occurrence of at least four different cellular mechanisms for the loss of symbiotic algae from the host tissue: in situ degradation of algae, exocytic release of algae from the host, detachment of host cells containing algae, and death of host cells containing algae...
2016: PloS One
Emily S Bellis, Dana K Howe, Dee R Denver
BACKGROUND: Coral reef ecosystems are declining in response to global climate change and anthropogenic impacts. Yet patterns of standing genetic variation within cnidarian species, a major determinant of adaptive potential, are virtually unknown at genome-scale resolution. We explore patterns of genome-wide polymorphism and identify candidate loci under selection in the sea anemone Aiptasia, an important laboratory model system for studying the symbiosis between corals and dinoflagellate algae of the genus Symbiodinium...
2016: BMC Genomics
Madeline Bucher, Iliona Wolfowicz, Philipp A Voss, Elizabeth A Hambleton, Annika Guse
Symbiosis between photosynthetic algae and heterotrophic organisms is widespread. One prominent example of high ecological relevance is the endosymbiosis between dinoflagellate algae of the genus Symbiodinium and reef-building corals, which typically acquire symbionts anew each generation during larval stages. The tropical sea anemone Aiptasia sp. is a laboratory model system for this endosymbiosis and, similar to corals, produces non-symbiotic larvae that establish symbiosis by phagocytosing Symbiodinium from the environment into the endoderm...
January 25, 2016: Scientific Reports
Clinton A Oakley, Michael F Ameismeier, Lifeng Peng, Virginia M Weis, Arthur R Grossman, Simon K Davy
Coral reef ecosystems are metabolically founded on the mutualism between corals and photosynthetic dinoflagellates of the genus Symbiodinium. The glass anemone Aiptasia sp. has become a tractable model for this symbiosis, and recent advances in genetic information have enabled the use of mass spectrometry-based proteomics in this model. We utilized label-free liquid chromatography electrospray-ionization tandem mass spectrometry to analyze the effects of symbiosis on the proteomes of symbiotic and aposymbiotic Aiptasia...
2016: Cellular Microbiology
Katie E Hillyer, Sergey Tumanov, Silas Villas-Bôas, Simon K Davy
Bleaching (dinoflagellate symbiont loss) is one of the greatest threats facing coral reefs. The functional cnidarian-dinoflagellate symbiosis, which forms coral reefs, is based on the bi-directional exchange of nutrients. During thermal stress this exchange breaks down; however, major gaps remain in our understanding of the roles of free metabolite pools in symbiosis and homeostasis. In this study we applied gas chromatography-mass spectrometry (GC-MS) to explore thermally induced changes in intracellular pools of amino and non-amino organic acids in each partner of the model sea anemone Aiptasia sp...
February 2016: Journal of Experimental Biology
Jennifer L Matthews, Ashley E Sproles, Clinton A Oakley, Arthur R Grossman, Virginia M Weis, Simon K Davy
Experimental manipulation of the symbiosis between cnidarians and photosynthetic dinoflagellates (Symbiodinium spp.) is crucial to advancing the understanding of the cellular mechanisms involved in host-symbiont interactions, and overall coral reef ecology. The anemone Aiptasia sp. is a model for cnidarian-dinoflagellate symbiosis, and notably it can be rendered aposymbiotic (i.e. dinoflagellate-free) and re-infected with a range of Symbiodinium types. Various methods exist for generating aposymbiotic hosts; however, they can be hugely time consuming and not wholly effective...
February 2016: Journal of Experimental Biology
Liping Wang, Xiaoyi Li, Dong Hu, Qiliang Lai, Zongze Shao
A novel bacterial strain, designated S2-2T, was isolated from the intestine of a sea cucumber Apostichopus japonicus in Xiapu, Fujian province, China. Strain S2-2T was found to be aerobic, Gram-stain-negative, pale yellow, rod-shaped, oxidase- and catalase-positive. Growth occurred at 15-36 °C (optimum, 25-32 °C), in the presence of 2-7% sea salt (w/v, optimum, 3-5%) and at pH 6-9 (optimum, pH 7.0). The isolate was able to hydrolyse gelatin, casein and DNA, but unable to degrade Tween 20, 40 and 80, starch and cellulose...
December 2015: International Journal of Systematic and Evolutionary Microbiology
Sebastian Baumgarten, Oleg Simakov, Lisl Y Esherick, Yi Jin Liew, Erik M Lehnert, Craig T Michell, Yong Li, Elizabeth A Hambleton, Annika Guse, Matt E Oates, Julian Gough, Virginia M Weis, Manuel Aranda, John R Pringle, Christian R Voolstra
The most diverse marine ecosystems, coral reefs, depend upon a functional symbiosis between a cnidarian animal host (the coral) and intracellular photosynthetic dinoflagellate algae. The molecular and cellular mechanisms underlying this endosymbiosis are not well understood, in part because of the difficulties of experimental work with corals. The small sea anemone Aiptasia provides a tractable laboratory model for investigating these mechanisms. Here we report on the assembly and analysis of the Aiptasia genome, which will provide a foundation for future studies and has revealed several features that may be key to understanding the evolution and function of the endosymbiosis...
September 22, 2015: Proceedings of the National Academy of Sciences of the United States of America
Po-Ching Song, Tsung-Meng Wu, Ming-Chang Hong, Ming-Chyuan Chen
Coral bleaching is the consequence of disruption of the mutualistic Cnidaria-dinoflagellate association. Elevated seawater temperatures have been proposed as the most likely cause of coral bleaching whose severity is enhanced by a limitation in the bioavailability of iron. Iron is required by numerous organisms including the zooxanthellae residing inside the symbiosome of cnidarian cells. However, the knowledge of how symbiotic zooxanthellae obtain iron from the host cells and how elevated water temperature affects the association is very limited...
October 2015: Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology
P L Howe, A J Reichelt-Brushett, R Krassoi, T Micevska
The sea anemone Exaiptasia pallida (formally Aiptasia pulchella) has been identified as a valuable test species for tropical marine ecotoxicology. Here, the sensitivities of newly developed endpoints for E. pallida to two unidentified whole effluents were compared to a standard suite of temperate toxicity test species and endpoints that are commonly used in toxicological risk assessments for tropical marine environments. For whole effluent 1 (WE1), a 96-h lethal concentration 50 % (LC50) of 40 (95 % confidence intervals, 30-54) % v/v and a 12-day LC50 of 12 (9-15) % v/v were estimated for E...
September 2015: Environmental Science and Pollution Research International
Miguel C Leal, Kenneth Hoadley, D Tye Pettay, Alejandro Grajales, Ricardo Calado, Mark E Warner
The association between cnidarians and photosynthetic dinoflagellates within the genus Symbiodinium is a prevalent relationship in tropical and subtropical marine environments. Although the diversity of Symbiodinium provides a possible axis for niche diversification, increased functional range and resilience to physical stressors such as elevated temperature, how such diversity relates to the physiological balance between autotrophy and heterotrophy of the host animal remains unknown. Here, we experimentally show interspecific and intraspecific variability of photosynthetic carbon fixation and subsequent translocation by Symbiodinium to the model cnidarian host Aiptasia pallida...
March 2015: Journal of Experimental Biology
Jörg Frommlet, Bárbara Guimarães, Lígia Sousa, João Serôdio, Artur Alves
A Gram-stain-negative, facultatively anaerobic, oxidase- and catalase-positive, rod-shaped bacterium, strain SYM1(T), was isolated from a culture of Symbiodinium sp., an algal symbiont of the sea anemone Aiptasia tagetes collected in Puerto Rico. Growth was observed at 4-40 °C (optimum 30 °C), at pH 5.0-11.0 (optimum pH 8.0) and with 0.5-8 % (optimum 2 %) (w/v) NaCl. Phylogenetic analyses of 16S rRNA gene sequences showed that strain SYM1(T) was a member of the genus Neptunomonas with the type strain of Neptunomonas naphthovorans as the closest phylogenetic relative with a pairwise sequence similarity of 98...
March 2015: International Journal of Systematic and Evolutionary Microbiology
Pelli L Howe, Amanda J Reichelt-Brushett, Malcolm W Clark
Currently few studies present sub-lethal toxicity data for tropical marine species, and there are no routine toxicity tests using marine cnidarians. The symbiotic sea anemone Aiptasia pulchella has been identified as a useful species for ecotoxicological risk assessment, and would provide a tropical marine cnidarian representative. Chronic sub-lethal toxicity tests assessing the effects of 28-day trace metal exposure on asexual reproduction in A. pulchella were investigated, and concentration-dependant reductions in the number of offspring that were produced were evident for all metal exposures...
November 2014: Ecotoxicology
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