Biology subjects

Da-Anoy, J.

Publications and source records attributed to Da-Anoy, J..

6 recordsLinked to original sources

bioRxiv2026

Heat and Nitrate Drive Metabolic and Immune Reprogramming Leading to the Collapse of Symbiosis in the Model Sea Anemone Aiptasia

The maintenance of endosymbiosis in cnidarians depends on the tight regulation of host immunity, cell cycle, and nutrient exchange, yet how these processes are impacted by interacting environmental stressors remains largely unknown. To address this, we employed physiological metrics, gene expression analysis, microbiome characterization, imaging (NF-{kappa}B localization, endoplasmic reticulum ultrastructure, EdU labeling), and stable isotope tracing in the model sea anemone Exaiptasia diaphana to examine the effects of heat and nitrate on these regulatory processes, individually and in combination. Heat treatment led to NF-{kappa}B activation, proteostatic stress, suppression of nutrient exchange, decreased cell-cycle progression, and microbiome restructuring, with all effects more pronounced in symbiotic than aposymbiotic anemones. In symbiotic anemones, nitrate partially offset these heat-induced responses through sustained carbon translocation, suggesting that the presence of symbionts, in conjunction with elevated nitrate, can temporarily buffer host thermal stress. However, prolonged combined exposure resulted in holobiont failure. These findings reveal that while nitrate enrichment can transiently delay the onset of bleaching, it does not preserve the regulatory networks required for symbiotic stability -- underscoring the vulnerability of cnidarian holobionts to the compounding effects of warming and nitrate pollution.

molecular biology↗

bioRxiv2025

Algae-specific Immune Modulation Influences Responses to Heat and Pathogen Challenge in a Symbiotic Coral

The role of symbiotic algae in coral life history and host health is well documented, but the immune and physiological trade-offs of hosting these symbionts remain less explored. While association with the algal symbionts of the genus Durusdinium is known to confer thermotolerance, it has also been linked to coral tissue loss under stress. We investigated whether algal type influences host immunity and stress responses in the tropical coral Pocillopora acuta. Durusdinium-hosting (D-hosting) P. acuta have distinct transcriptomic profiles, higher immune-related gene expression, and elevated baseline levels of immunity transcription factor NF-{kappa}B as compared to corals hosting Cladocopium (C-hosting). Under heat challenge, D-hosting P. acuta exhibited tissue loss, oxidative stress, immune and microbial dysregulation, whereas C-hosting P. acuta were more susceptible to bleaching, metabolic dysregulation, and decline in nitrogen-fixing and antioxidant-producing bacteria. Finally, infection with the the bacterium Vibrio coralliilyticus caused high tissue loss in D-hosting corals, but not in C-hosting corals. Our results suggest a mechanism for how Durusdinium association enhances thermotolerance yet predisposes corals to tissue damage under stress, suggesting immune trade-offs that can compromise host survival under multiple stressors.

genomics↗

bioRxiv2024

Antibiotic treatment and microbiome depletion slow cnidarian regeneration

Cnidarian microbiomes play an essential role in physiology and development, but how these communities influence tissue regeneration is poorly understood. Here, we examined the effects of antibiotic exposure on regeneration and microbial communities in two cnidarian models, the sea anemones Nematostella vectensis (non-symbiotic, hereafter, Nematostella) and Exaiptasia pallida (symbiotic, hereafter, Aiptasia). Bisected animals were incubated in either sterile or antibiotic-containing artificial seawater for seven days and regeneration was monitored daily. After seven days, tentacle number and length were measured, and microbial communities were profiled using metabarcoding of the V4 region of the 16S rRNA. Microbiome disruption was observed under antibiotic treatment in both species, resulting in decreased microbial load and shifts in relative abundances of some microbial taxa. However, Nematostella exhibited a greater reduction in microbial diversity and community shifts under antibiotic exposure, whereas Aiptasia showed only moderate changes in diversity. In both species, microbiome disruption was associated with slower regeneration rates and reduced tentacle number and length, suggesting a functional role for the microbiome in cnidarian regeneration. Our findings suggest that host-microbiome interactions in both symbiotic and aposymbiotic anemones are important for the maintenance of regenerative processes. These findings provide insight into how cnidarians and their microbiomes respond to environmental stressors, with implications for predicting cnidarian resilience in the context of emerging threats to the marine environment.

developmental biology↗

bioRxiv2024

Ex situ spawning, larval development, and settlement in the massive reef-building coral Porites lobata in Palau

Reproduction, embryological development, and settlement of corals are critical for survival of coral reefs through larval propagation. Yet, for many species of corals, a basic understanding of the early life-history stages is lacking. In this study, we report our observations for ex situ reproduction in the massive reef-building coral Porites lobata across two years. Spawning occurred in April and May, on the first day after the full moon with at least two hours of darkness between sunset and moonrise, on a rising tide. Only a small proportion of corals observed had mature gametes or spawned (17 - 35%). Eggs were 185 - 311 m in diameter, spherical, homogenous, and provisioned with 95 - 155 Symbiodiniaceae algae. Males spawned before females, and ex situ fertilization rates were high for the first 2 hours after egg release. P. lobata larvae were elliptical, approximately 300 m long, and symbiotic. Just two days after fertilization, many larvae swam near the bottom of culture dishes and were competent to settle. Settlers began calcification two days after metamorphosis, and tentacles were developed 10 days after attachment. Our observations contrast with previous studies by suggesting an abbreviated pelagic larval period in P. lobata, which could lead to the isolation of some populations. The high thermal tolerance and a broad geographic range of P. lobata suggest this species could locally adapt to a wide range of environmental conditions, especially if larvae are locally retained. The results of this study can inform future work on reproduction, larval biology, dispersal, and recruitment of P. lobata, which could have an ecological advantage over less resilient coral species under future climate change.

ecology↗

bioRxiv2024

Interspecies differences in the transcriptome response of corals to acute heat stress

Rising sea surface temperatures threaten the survival of corals worldwide, with coral bleaching events becoming more commonplace. However, different coral species are known to exhibit variable levels of susceptibility to thermal stress events. To elucidate genetic mechanisms that may underlie these differences, we compared the gene complement of four coral species, Favites colemani, Montipora digitata, Acropora digitifera, and Seriatopora caliendrum, that were previously demonstrated to have differing responses to acute thermal stress. We found that more tolerant species, like F. colemani and M. digitata, possess a greater abundance of antioxidant protein families and chaperones. Under acute thermal stress conditions, only S. caliendrum showed a significant bleaching response, which was accompanied by activation of DNA damage response network and drastic upregulation of stress response genes (SRGs). This suggests that differences in SRG complement, as well as the mechanisms that control SRG expression response, contribute to the ability of corals to maintain stable physiological functions that is required to survive shifts in seawater temperature.

genomics↗

bioRxiv2024

Single-cell RNA-sequencing reveals immune system compartmentalization under symbiosis in the stony coral Oculina arbuscula

Many cnidarians host single-celled algae within gastrodermal cells, yielding a mutually beneficial exchange of nutrients between host and symbiont, and dysbiosis can lead to host mortality. Previous research has uncovered symbiosis tradeoffs, including suppression of immune pathways in cnidarians hosting intracellular algae and correlations between symbiotic state and pathogen susceptibility. Here, we used a multiomic approach to characterize symbiotic states of the facultatively symbiotic coral Oculina arbuscula by generating genotype-controlled fragments of symbiotic and aposymbiotic tissue. 16S metabarcoding showed no difference in bacterial communities between symbiotic states. Whole-organism proteomics revealed differential abundance of proteins related to immunity, confirming immune suppression during symbiosis. Finally, single-cell RNAseq identified diverse cell clusters within seven cell types across symbiotic states. Specifically, the gastrodermal cell clusters containing algal-hosting cells from symbiotic tissue had higher expression of nitrogen cycling and sugar transport genes than aposymbiotic gastrodermal cells. Furthermore, differential enrichment of immune system gene pathways and lower expression of genes involved in immune regulation were observed in these gastrodermal cells from symbiotic tissue. However, no differences in immune gene expression in the immune cell cluster were observed between symbiotic states. This work reveals a compartmentalization of immune system regulation in specific gastrodermal cells in symbiosis, which may limit symbiosis tradeoffs by simultaneously dampening immunity in algal-hosting cells while maintaining general organismal immunity.

genomics↗