Outcomes of Infections of Sea Anemone Aiptasia pallida with Vibrio spp. Pathogenic to Corals

Zaragoza, William J.; Krediet, Cory J.; Meyer, Julie; Canas, Gabriela; Ritchie, Kim B.; Teplitski, Max

doi:10.1007/s00248-014-0397-2

Cited by 28 publications

(38 citation statements)

References 32 publications

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“…Maximum lifespans were calculated using Kaplan-Meier survival curves (Kaplan & Meier 1958, Zaragoza et al 2014. Population turnover time was calculated as the time required for the complete replacement of individuals, which was the reciprocal of the turnover rate (Hughes 1984, Hughes & Jackson 1985, according to the turnover (T ) formula:…”

Section: Discussionmentioning

confidence: 99%

Population dynamics of corkscrew sea anemones Bartholomea annulata in the Florida Keys

O’Reilly¹,

Chadwick²

2017

Mar. Ecol. Prog. Ser.

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Corkscrew sea anemones Bartholomea annulata are important ecologically as hubs of a mutualistic network involving cleaner shrimps and client fishes on Caribbean reefs. They also are collected for the ornamental aquarium trade, but little is known about their population dynamics to support conservation management. We quantified variation in population structure among regions of the Florida Keys and levels of human impact within region. The Upper Keys and lowimpact sites supported higher population abundance and proportions of small anemones than the Lower Keys and high-impact sites. At 2 sites where we monitored anemone dynamics every 2 mo for 1 yr, individuals recruited frequently and grew rapidly to maximum body size and then remained static or shrank. Fewer than half the individuals survived all year, indicating rapid population turnover, with mortality occurring mostly among small individuals or large ones that appeared to senesce beforehand. Stasis of large individuals (or lack thereof) exerted the most influence on population size. We conclude that in Florida, corkscrew anemones experience relatively high recruitment and survival at sites with low human impact and in the Upper Keys, where summer water temperatures are cooler than in the Lower Keys. Populations are highly dynamic and appear to rely on frequent recruitment, potentially linked to the presence of resident adults at high enough abundances for fertilization of broadcast propagules. The ephemeral nature of these anemones has important implications for the dynamics of their anemoneshrimp symbionts, for reef fishes that utilize them as parasite cleaning stations, and for the conservation management of their populations.

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Section: Discussionmentioning

confidence: 99%

Population dynamics of corkscrew sea anemones Bartholomea annulata in the Florida Keys

O’Reilly¹,

Chadwick²

2017

Mar. Ecol. Prog. Ser.

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“…Although not pathogenic at water temperatures below 24°C, V. coralliilyticus photoinactivates coral symbionts between temperatures 24°C and 26.5°C (27,29). Above 27°C, V. coralliilyticus is highly pathogenic due to its ability to lyse coral and anemone tissues (27,28,30). As global ocean temperatures rise, the temperature-dependent pathogenicity of V. coralliilyticus threatens many coral species.…”

mentioning

confidence: 99%

Sea anemone model has a single Toll-like receptor that can function in pathogen detection, NF-κB signal transduction, and development

Brennan

Messerschmidt

Williams

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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In organisms from insects to vertebrates, Toll-like receptors (TLRs) are primary pathogen detectors that activate downstream pathways, specifically those that direct expression of innate immune effector genes. TLRs also have roles in development in many species. The sea anemone is a useful cnidarian model to study the origins of TLR signaling because its genome encodes a single TLR and homologs of many downstream signaling components, including the NF-κB pathway. We have characterized the single TLR (Nv-TLR) and demonstrated that it can activate canonical NF-κB signaling in human cells. Furthermore, we show that the intracellular Toll/IL-1 receptor (TIR) domain of Nv-TLR can interact with the human TLR adapter proteins MAL and MYD88. We demonstrate that the coral pathogen causes a rapidly lethal disease in and that heat-inactivated and bacterial flagellin can activate a reconstituted Nv-TLR-to-NF-κB pathway in human cells. By immunostaining of anemones, we show that Nv-TLR is expressed in a subset of cnidocytes and that many of these Nv-TLR-expressing cells also express Nv-NF-κB. Additionally, the nematosome, which is a-specific multicellular structure, expresses Nv-TLR and many innate immune pathway homologs and can engulf Morpholino knockdown indicates that Nv-TLR also has an essential role during early embryonic development. Our characterization of this primitive TLR and identification of a bacterial pathogen for reveal ancient TLR functions and provide a model for studying the molecular basis of cnidarian disease and immunity.

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“…The rapid onset of bleaching in the heat-treated anemones may have been linked to lack of food. Starvation has been practiced in previous E. diaphana experiments [21,23,[30][31][32] despite observed reductions in Symbiodiniaceae cell density following food deprivation [67][68][69], but the possible impact of this on experimental outcomes has rarely been acknowledged [70]. Our data suggest that, in future work, continued feeding is advisable, but at levels that maintain normal thermal tolerance rather than enhance it as seen in some coral species under heterotrophic conditions [71][72][73].…”

Section: Factors Underpinning Bleachingmentioning

confidence: 74%

“…Line plots of the six most abundant bacterial classes for the control and heat-treated anemones were generated to assess changes in community composition across the study period at a high taxonomic level. Bacteria of the genus Vibrio frequently cause disease in corals and E. diaphana at temperatures above 27 • C due to the upregulation of virulence factors [32,60]. Therefore, changes in the relative abundance of Vibrio ASVs were investigated to assess their prevalence, and hence disease-causing potential in GBR E. diaphana at elevated temperature.…”

Section: Analysis Of Changes In Abundance Of Selected Bacterial Taxamentioning

confidence: 99%

“…The anemones were not fed after acclimation to minimize the introduction of bacteria that could have contributed to their bacterial compositions. Starvation was considered reasonable as it is a common practice in E. diaphana studies [21,23,[30][31][32]. On sampling days, the anemones were removed from the incubators 30-60 min after the daylight cycle and dark-adapted for 10 min before maximum quantum yield (F v /F m ) was measured with an imaging pulse amplitude modulation (iPAM) fluorometer (IMAGING-PAM M-Series, Heinz Walz, Effeltrich, Germany).…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Thermal Stress on the Bacterial Microbiome of Exaiptasia diaphana

2019

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Coral bleaching linked to climate change has generated interest in the response of coral's bacterial microbiome to thermal stress. The sea anemone, Exaiptasia diaphana, is a popular coral model, but the response of its bacteria to thermal stress has been barely explored. To address this, we compared the bacterial communities of Great Barrier Reef (GBR) E. diaphana maintained at 26 • C or exposed to increasing temperature (26-33 • C) over two weeks. Communities were analyzed by metabarcoding of the bacterial 16S rRNA gene. Bleaching and Symbiodiniaceae health were assessed by Symbiodiniaceae cell density and dark-adapted quantum yield (F v /F m ), respectively. Significant bleaching and reductions in F v /F m occurred in the heat-treated anemones above 29 • C. Overall declines in bacterial alpha diversity in all anemones were also observed. Signs of bacterial change emerged above 31 • C. Some initial outcomes may have been influenced by relocation or starvation, but collectively, the bacterial community and taxa-level data suggested that heat was the primary driver of change above 32 • C. Six bacterial indicator species were identified as potential biomarkers for thermal stress. We conclude that the bacterial microbiome of GBR E. diaphana is generally stable until a thermal threshold is surpassed, after which significant changes occur. resistance or susceptibility during thermal stress have been observed [12][13][14]. This highlights the need for controlled, laboratory-based experiments to clarify the relationship between temperature-related bacterial community shifts and bleaching in cnidarians [15][16][17].The sea anemone, Exaiptasia diaphana, is a much-used model for coral symbiosis studies [18,19]. Its ability to propagate asexually for rapid growth of clonal populations, basic maintenance requirements and coral-like bleaching response to environmental stressors have seen it widely adopted by the research community and several clonal lines of different geographic origin and algal symbiont type have been established. However, studies using E. diaphana to explore cnidarian responses to heat stress have focused largely on aspects of the host-Symbiodiniaceae relationship [20][21][22][23][24][25], whilst its bacterial microbiome has been almost wholly neglected and data from only two studies are available.In a 2010 Master's thesis, E. diaphana of unspecified origin were exposed to temperature ramped from 26 • C to 31 • C over ten days, then held at 31 • C for four days [26]. No significant differences between the associated bacterial communities of control and treated anemones were detected across the study period. However, poor resolution of chosen molecular biology methods negatively impacted the findings. In addition, exposing the anemones to a maximum of 31 • C meant the anemones may not have been thermally stressed, and no measurements of algal cell density or photosynthetic performance were taken to assess their condition. Although the study revealed few insights, it is acknowledged as the first investigation...

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Outcomes of Infections of Sea Anemone Aiptasia pallida with Vibrio spp. Pathogenic to Corals

Cited by 28 publications

References 32 publications

Population dynamics of corkscrew sea anemones Bartholomea annulata in the Florida Keys

Population dynamics of corkscrew sea anemones Bartholomea annulata in the Florida Keys

Sea anemone model has a single Toll-like receptor that can function in pathogen detection, NF-κB signal transduction, and development

The Effect of Thermal Stress on the Bacterial Microbiome of Exaiptasia diaphana

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