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John E Parkinson, Trevor R Tivey, Paige E Mandelare, Donovon A Adpressa, Sandra Loesgen, Virginia M Weis
Mutualisms between cnidarian hosts and dinoflagellate endosymbionts are foundational to coral reef ecosystems. These symbioses are often re-established every generation with high specificity, but gaps remain in our understanding of the cellular mechanisms that control symbiont recognition and uptake dynamics. Here, we tested whether differences in glycan profiles among different symbiont species account for the different rates at which they initially colonize aposymbiotic polyps of the model sea anemone Aiptasia ( Exaiptasia pallida )...
2018: Frontiers in Microbiology
Michal Sorek, Yisrael Schnytzer, Hiba Waldman Ben-Asher, Vered Chalifa Caspi, Chii-Shiarng Chen, David J Miller, Oren Levy
BACKGROUND: All organisms employ biological clocks to anticipate physical changes in the environment; however, the integration of biological clocks in symbiotic systems has received limited attention. In corals, the interpretation of rhythmic behaviours is complicated by the daily oscillations in tissue oxygen tension resulting from the photosynthetic and respiratory activities of the associated algal endosymbiont Symbiodinium. In order to better understand the integration of biological clocks in cnidarian hosts of Symbiodinium, daily rhythms of behaviour and gene expression were studied in symbiotic and aposymbiotic morphs of the sea-anemone Aiptasia diaphana...
May 9, 2018: Microbiome
Maren Ziegler, Elizabeth Stone, Daniel Colman, Cristina Takacs-Vesbach, Ursula Shepherd
Large-scale environmental disturbances may impact both partners in coral host-Symbiodinium systems. Elucidation of the assembly patterns in such complex and interdependent communities may enable better prediction of environmental impacts across coral reef ecosystems. In this study, we investigated how the community composition and diversity of dinoflagellate symbionts in the genus Symbiodinium were distributed among 12 host species from six taxonomic orders (Actinaria, Alcyonacea, Miliolida, Porifera, Rhizostoma, Scleractinia) and in the reef water and sediments at Lizard Island, Great Barrier Reef before the 3rd Global Coral Bleaching Event...
April 26, 2018: Journal of Phycology
Yasmin Gabay, Virginia M Weis, Simon K Davy
The genus Symbiodinium is physiologically diverse and so may differentially influence symbiosis establishment and function. To explore this, we inoculated aposymbiotic individuals of the sea anemone Exaiptasia pallida (commonly referred to as "Aiptasia"), a model for coral symbiosis, with one of five Symbiodinium species or types (S. microadriaticum, S. minutum, phylotype C3, S. trenchii, or S. voratum). The spatial pattern of colonization was monitored over time via confocal microscopy, and various physiological parameters were measured to assess symbiosis functionality...
February 2018: Biological Bulletin
Anne Wietheger, Dorota E Starzak, Kevin S Gould, Simon K Davy
Oxidative stress inside cells occurs when the production of reactive oxygen species (ROS) is no longer efficiently counterbalanced by the generation of antioxidants. In this study, we measured the intracellular production of ROS, including hydrogen peroxide (H2 O2 ), superoxide (O2 - ), and singlet oxygen (1 O2 ), in cultured dinoflagellates of the genus Symbiodinium under thermal and oxidative stress. ROS tagged with fluorescent probes were measured by flow cytometry. Dissimilar Symbiodinium internal transcribed spacer 2 (ITS2) clades or phylotypes (A1, B2, E, F1) produced ROS in different quantities in response to stress...
February 2018: Biological Bulletin
Daniel G Merselis, Diego Lirman, Mauricio Rodriguez-Lanetty
Accelerating anthropogenic climate change threatens to destroy coral reefs worldwide through the processes of bleaching and disease. These major contributors to coral mortality are both closely linked with thermal stress intensified by anthropogenic climate change. Disease outbreaks typically follow bleaching events, but a direct positive linkage between bleaching and disease has been debated. By tracking 152 individual coral ramets through the 2014 mass bleaching in a South Florida coral restoration nursery, we revealed a highly significant negative correlation between bleaching and disease in the Caribbean staghorn coral, Acropora cervicornis ...
2018: PeerJ
Maha J Cziesielski, Yi Jin Liew, Guoxin Cui, Sebastian Schmidt-Roach, Sara Campana, Claudius Marondedze, Manuel Aranda
Corals and their endosymbiotic dinoflagellates of the genus Symbiodinium have a fragile relationship that breaks down under heat stress, an event known as bleaching. However, many coral species have adapted to high temperature environments such as the Red Sea (RS). To investigate mechanisms underlying temperature adaptation in zooxanthellate cnidarians we compared transcriptome- and proteome-wide heat stress response (24 h at 32°C) of three strains of the model organism Aiptasia pallida from regions with differing temperature profiles; North Carolina (CC7), Hawaii (H2) and the RS...
April 25, 2018: Proceedings. Biological Sciences
Nils Rädecker, Jean-Baptiste Raina, Mathieu Pernice, Gabriela Perna, Paul Guagliardo, Matt R Kilburn, Manuel Aranda, Christian R Voolstra
The symbiosis between cnidarian hosts and microalgae of the genus Symbiodinium provides the foundation of coral reefs in oligotrophic waters. Understanding the nutrient-exchange between these partners is key to identifying the fundamental mechanisms behind this symbiosis, yet has proven difficult given the endosymbiotic nature of this relationship. In this study, we investigated the respective contribution of host and symbiont to carbon and nitrogen assimilation in the coral model anemone Aiptaisa. For this, we combined traditional measurements with nanoscale secondary ion mass spectrometry (NanoSIMS) and stable isotope labeling to investigate patterns of nutrient uptake and translocation both at the organismal scale and at the cellular scale...
2018: Frontiers in Physiology
Jeroen A J M van de Water, Denis Allemand, Christine Ferrier-Pagès
Octocorals are one of the most ubiquitous benthic organisms in marine ecosystems from the shallow tropics to the Antarctic deep sea, providing habitat for numerous organisms as well as ecosystem services for humans. In contrast to the holobionts of reef-building scleractinian corals, the holobionts of octocorals have received relatively little attention, despite the devastating effects of disease outbreaks on many populations. Recent advances have shown that octocorals possess remarkably stable bacterial communities on geographical and temporal scales as well as under environmental stress...
April 2, 2018: Microbiome
Gretchen Goodbody-Gringley, Justin Waletich
Scleractinian corals have global ecological, structural, social, and economic importance that is disproportionately large relative to their areal extent. These reef building corals form the architectural framework for shallow water tropical reef systems, supporting the most productive and biologically diverse marine ecosystems on Earth (Veron, 1995). Reef-building scleractinian species are dependent on photosynthetic products supplied by symbiotic zooxanthellae of the genus Symbiodinium, restricting their distribution to the photic zone (Stambler, 2011)...
April 2, 2018: Ecology
Christine Guzman, Xue Han, Eiichi Shoguchi, Sile Nic Chormaic
The partnership between coral and its algal symbionts, Symbiodinium, is crucial to the global environment. Yet, the regulatory process within the photosynthetic machinery of Symbiodinium is still not clearly understood. Here, we studied the influence of light stress from focused red and blue lasers on single Symbiodinium cells. Fluorescence signals were measured to show cell response. Increasing the incident laser power or the exposure time resulted in an increase followed by a decline in fluorescence intensity...
March 29, 2018: Methods and Applications in Fluorescence
James K H Fang, Christine H L Schönberg, Matheus A Mello-Athayde, Michelle Achlatis, Ove Hoegh-Guldberg, Sophie Dove
The bioeroding sponge Cliona orientalis is photosymbiotic with dinoflagellates of the genus Symbiodinium and is pervasive on the Great Barrier Reef. We investigated how C. orientalis responded to past and future ocean conditions in a simulated community setting. The experiment lasted over an Austral summer under four carbon dioxide emission scenarios: a pre-industrial scenario (PI), a present-day scenario (PD; control), and two future scenarios of combined ocean acidification and ocean warming, i.e., B1 (intermediate) and A1FI (extreme)...
March 24, 2018: Oecologia
Wirulda Pootakham, Wuttichai Mhuantong, Lalita Putchim, Thippawan Yoocha, Chutima Sonthirod, Wasitthee Kongkachana, Duangjai Sangsrakru, Chaiwat Naktang, Nukoon Jomchai, Nalinee Thongtham, Sithichoke Tangphatsornruang
Coral-associated microorganisms play an important role in their host fitness and survival. A number of studies have demonstrated connections between thermal tolerance in corals and the type/relative abundance of Symbiodinium they harbor. More recently, the shifts in coral-associated bacterial profiles were also shown to be linked to the patterns of coral heat tolerance. Here, we investigated the dynamics of Porites lutea-associated bacterial and algal communities throughout a natural bleaching event, using full-length 16S rRNA and internal transcribed spacer sequences (ITS) obtained from PacBio circular consensus sequencing...
March 23, 2018: MicrobiologyOpen
Philip Mercurio, Geoff Eaglesham, Stephen Parks, Matt Kenway, Victor Beltran, Florita Flores, Jochen F Mueller, Andrew P Negri
The toxicity of herbicide degradation (transformation) products is rarely taken into account, even though these are commonly detected in the marine environment, sometimes at concentrations higher than the parent compounds. Here we assessed the potential contribution of toxicity by transformation products of five photosystem II herbicides to coral symbionts (Symbiodinium sp.), the green algae Dunaliella sp., and prawn (Penaeus monodon) larvae. Concentration-dependent inhibition of photosynthetic efficiency (∆F/Fm ') was observed for all herbicides in both microalgal species...
March 19, 2018: Scientific Reports
Sheila A Kitchen, Angela Z Poole, Virginia M Weis
In host-microbe interactions, signaling lipids function in interpartner communication during both the establishment and maintenance of associations. Previous evidence suggests that sphingolipids play a role in the mutualistic cnidarian-Symbiodinium symbiosis. Exogenously applied sphingolipids have been shown to alter this partnership, though endogenous host regulation of sphingolipids by the sphingosine rheostat under different symbiotic conditions has not been characterized. The rheostat regulates levels of pro-survival sphingosine-1-phosphate (S1P) and pro-apoptotic sphingosine (Sph) through catalytic activities of sphingosine kinase (SPHK) and S1P phosphatase (SGPP)...
December 2017: Biological Bulletin
Christabel Y L Chan, Kum C Hiong, Mel V Boo, Celine Y L Choo, Wai P Wong, Shit F Chew, Yuen K Ip
Giant clams live in nutrient-poor reef waters of the Indo-Pacific and rely on symbiotic dinoflagellates ( Symbiodinium spp., also known as zooxanthellae) for nutrients. As the symbionts are nitrogen deficient, the host clam has to absorb exogenous nitrogen and supply it to them. This study aimed to demonstrate light-enhanced urea absorption in the fluted giant clam, Tridacna squamosa , and to clone and characterize the urea active transporter, DUR3-like, from its ctenidium (gill). Results indicate that T. squamosa could absorb exogenous urea, and the rate of urea uptake in light was significantly higher than that in darkness...
March 14, 2018: Journal of Experimental Biology
Jan D Brüwer, Christian R Voolstra
Current research posits that all multicellular organisms live in symbioses with associated microorganisms and form so-called metaorganisms or holobionts. Cnidarian metaorganisms are of specific interest given that stony corals provide the foundation of the globally threatened coral reef ecosystems. To gain first insight into viruses associated with the coral model system Aiptasia ( sensu Exaiptasia pallida ), we analyzed an existing RNA-Seq dataset of aposymbiotic, partially populated, and fully symbiotic Aiptasia CC7 anemones with Symbiodinium ...
2018: PeerJ
Rachel R S Fam, Kum C Hiong, Celine Y L Choo, Wai P Wong, Shit F Chew, Yuen K Ip
Giant clams harbor symbiotic zooxanthellae (Symbiodinium), which are nitrogen-deficient, mainly in the fleshy and colorful outer mantle. This study aimed to sequence and characterize the algal Glutamine Synthetase (GS) and Glutamate Synthase (GLT), which constitute the glutamate synthase cycle (or GS-GOGAT cycle, whereby GOGAT is the protein acronym of GLT) of nitrogen assimilation, from the outer mantle of the fluted giant clam, Tridacna squamosa. We had identified a novel GS-like cDNA coding sequence of 2325 bp, and named it as T...
May 20, 2018: Gene
Blake D Ramsby, Mia O Hoogenboom, Steve Whalan, Nicole S Webster
Bioeroding sponges break down calcium carbonate substratum, including coral skeleton, and their capacity for reef erosion is expected to increase in warmer and more acidic oceans. However, elevated temperature can disrupt the functionally important microbial symbionts of some sponge species, often with adverse consequences for host health. Here, we provide the first detailed description of the microbial community of the bioeroding sponge Cliona orientalis and assess how the community responds to seawater temperatures incrementally increasing from 23°C to 32°C...
April 2018: Molecular Ecology
Claudia Pogoreutz, Nils Rädecker, Anny Cárdenas, Astrid Gärdes, Christian Wild, Christian R Voolstra
The importance of Symbiodinium algal endosymbionts and a diverse suite of bacteria for coral holobiont health and functioning are widely acknowledged. Yet, we know surprisingly little about microbial community dynamics and the stability of host-microbe associations under adverse environmental conditions. To gain insight into the stability of coral host-microbe associations and holobiont structure, we assessed changes in the community structure of Symbiodinium and bacteria associated with the coral Pocillopora verrucosa under excess organic nutrient conditions...
February 2018: Ecology and Evolution
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