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Maria Byrne - One of the best experts on this subject based on the ideXlab platform.
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embryo microinjection of the lecithotrophic sea urchin Heliocidaris erythrogramma
Journal of Biological Methods, 2019Co-Authors: Allison Edgar, Maria Byrne, Gregory A WrayAbstract:Microinjection is a common embryological technique used for many types of experiments, including lineage tracing, manipulating gene expression, or genome editing. Injectable reagents include mRNA overexpression, mis-expression, or dominant-negative experiments to examine a gene of interest, a morpholino antisense oligo to prevent translation of an mRNA or spliceoform of interest and CRISPR-Cas9 reagents. Thus, the technique is broadly useful for basic embryological studies, constructing gene regulatory networks, and directly testing hypotheses about cis-regulatory and coding sequence changes underlying the evolution of development. However, the methods for microinjection in typical planktotrophic marine invertebrates may not work well in the highly modified eggs and embryos of lecithotrophic species. This protocol is optimized for the lecithotrophic sea urchin Heliocidaris erythrogramma.
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a comparative analysis of egg provisioning using mass spectrometry during rapid life history evolution in sea urchins
Evolution & Development, 2019Co-Authors: Phillip L Davidson, Maria Byrne, Will J Thompson, Matthew W Foster, Arthur M Moseley, Gregory A WrayAbstract:A dramatic life history switch that has evolved numerous times in marine invertebrates is the transition from planktotrophic (feeding) to lecithotrophic (nonfeeding) larval development-an evolutionary tradeoff with many important developmental and ecological consequences. To attain a more comprehensive understanding of the molecular basis for this switch, we performed untargeted lipidomic and proteomic liquid chromatography-tandem mass spectrometry on eggs and larvae from three sea urchin species: the lecithotroph Heliocidaris erythrogramma, the closely related planktotroph Heliocidaris tuberculata, and the distantly related planktotroph Lytechinus variegatus. We identify numerous molecular-level changes possibly associated with the evolution of lecithotrophy in H. erythrogramma. We find the massive lipid stores of H. erythrogramma eggs are largely composed of low-density, diacylglycerol ether lipids that, contrary to expectations, appear to support postmetamorphic development and survivorship. Rapid premetamorphic development in this species may instead be powered by upregulated carbohydrate metabolism or triacylglycerol metabolism. We also find proteins involved in oxidative stress regulation are upregulated in H. erythrogramma eggs, and apoB-like lipid transfer proteins may be important for echinoid oogenic nutrient provisioning. These results demonstrate how mass spectrometry can enrich our understanding of life history evolution and organismal diversity by identifying specific molecules associated with distinct life history strategies and prompt new hypotheses about how and why these adaptations evolve.
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Early development of the feeding larva of the sea urchin Heliocidaris tuberculata: role of the small micromeres
Development Genes and Evolution, 2019Co-Authors: Valerie B Morris, Paula Cisternas, Demian Koop, Eleanor Kable, Maria ByrneAbstract:The two modes of development in sea urchins are direct development, in which the adult develops directly from the gastrula to the adult and does not feed, and indirect development, in which the adult develops indirectly through a feeding larva. In this account of the indirect, feeding larva of Heliocidaris tuberculata , the question raised is whether an evolutionary difference of unequal cell divisions contributes to the development of feeding structures in the indirect larva. In indirect development, the cell divisions at the fourth and fifth cell cycles of the zygote are unequal, with four small micromeres formed at the vegetal pole at the fifth cell division. In direct development, these cell divisions are not unequal. From their position at the head of the archenteron, the small micromeres are strategically located to contribute to the feeding tissues of the larva and the adult of H. tuberculata .
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the effect of warming on mortality metabolic rate heat shock protein response and gonad growth in thermally acclimated sea urchins Heliocidaris erythrogramma
Marine Biology, 2018Co-Authors: Januar Harianto, Hong D Nguyen, Sebastian P Holmes, Maria ByrneAbstract:Environmental temperature affects the physiology and fitness of ectotherms, an important consideration in a warming ocean. We investigated the effects of acclimation to increased temperature in the Australian sea urchin, Heliocidaris erythrogramma. After a gradual introduction to increasing temperature (1 °C 6 day−1), sea urchins were held for ~ 3 months in four treatments at three elevated temperatures (22, 24 and 26 °C) and the median annual temperature, 20 °C. The effect of elevated temperature on survival, metabolic rate, Q10, heat-shock protein (HSP70) expression, gonad index and gonad histology were examined. There was no detectable effect of temperature on metabolic rate for the 22 and 24 °C treatments, although survival decreased by 23% in the 24 °C treatment and there was an increase in mean HSP70 expression. At 26 °C, metabolic rate was lower than at 22 and 24 °C, but was similar to controls, indicating that metabolic depression may have occurred, whereas survival decreased by 31% and HSP70 expression increased threefold. It is clear that there is an active physiological response in urchins held at the highest temperatures. The deleterious effect of living at temperatures projected for the future indicates that the persistence of future populations of H. erythrogramma will depend on acclimation as habitat warming continues.
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expression of genes and proteins of the pax six eya dach network in the metamorphic sea urchin insights into development of the enigmatic echinoderm body plan and sensory structures
Developmental Dynamics, 2018Co-Authors: Maria Byrne, Valerie B Morris, Demian Koop, Juanita Chui, Gregory A Wray, Paula CisternasAbstract:Background: Photoreception-associated genes of the Pax-Six-Eya-Dach network (PSEDN) are deployed for many roles in addition to photoreception development. In this first study of PSEDN genes during development of the pentameral body in sea urchins, we investigated their spatial expression in Heliocidaris erythrogramma. Results: Expression of PSEDN genes in the hydrocoele of early (Dach, Eya, Six1/2) and/or late (Pax6, Six3/6) larvae, and the five hydrocoele lobes, the first morphological expression of pentamery, supports a role in body plan development. Pax6, Six1/2 and Six3/6 were localized to the primary and/or secondary podia and putative sensory/neuronal cells. Six1/2 and Six3/6 were expressed in the neuropil region in the terminal disc of the podia. Dach was localized to spines. Sequential up regulation of gene expression as new podia and spines formed was evident. Rhabdomeric opsin and pax6 protein were localized to cells in the primary podia and spines. Conclusion: Our results support roles for PSEDN genes in development of the pentameral body plan, contributing to our understanding of how the most unusual body plan in the Bilateria may have evolved. Development of sensory cells within the Pax-Six expression field is consistent with the role of these genes in sensory cell development in diverse species. This article is protected by copyright. All rights reserved.
Rudolf A Raff - One of the best experts on this subject based on the ideXlab platform.
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Gene expression during sea urchin development reflects known phylogenetic relationships between species.
2016Co-Authors: Jennifer W. Israel, Rudolf A Raff, Maria Byrne, Megan L. Martik, Elizabeth C. Raff, David R. Mcclay, Gregory A WrayAbstract:(A) Our study includes three sea urchin species: the sister species H. tuberculata (planktotroph) and H. erythrogramma (lecithotroph), which diverged approximately 5 Myr, and an outgroup species L. variegatus (planktotroph), which diverged approximately 35–45 Myr ago [44, 50]. (B) Our developmental time course includes seven stages across each species, from unfertilized eggs to early larvae. (C) Principal component (PC) analysis of gene expression (S1 Data). PC1 explains 36% of the overall variation and clearly separated early (egg through 32-cell stage) from later developmental stages (blastula through early larva), whereas PC2 separated L. variegatus from the two Heliocidaris species, corresponding to their phylogenetic relationships.
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Comparative Developmental Transcriptomics Reveals Rewiring of a Highly Conserved Gene Regulatory Network during a Major Life History Switch in the Sea Urchin Genus Heliocidaris.
Public Library of Science (PLoS), 2016Co-Authors: Jennifer W. Israel, Rudolf A Raff, Maria Byrne, Megan L. Martik, Elizabeth C. Raff, David R. Mcclay, Gregory A WrayAbstract:The ecologically significant shift in developmental strategy from planktotrophic (feeding) to lecithotrophic (nonfeeding) development in the sea urchin genus Heliocidaris is one of the most comprehensively studied life history transitions in any animal. Although the evolution of lecithotrophy involved substantial changes to larval development and morphology, it is not known to what extent changes in gene expression underlie the developmental differences between species, nor do we understand how these changes evolved within the context of the well-defined gene regulatory network (GRN) underlying sea urchin development. To address these questions, we used RNA-seq to measure expression dynamics across development in three species: the lecithotroph Heliocidaris erythrogramma, the closely related planktotroph H. tuberculata, and an outgroup planktotroph Lytechinus variegatus. Using well-established statistical methods, we developed a novel framework for identifying, quantifying, and polarizing evolutionary changes in gene expression profiles across the transcriptome and within the GRN. We found that major changes in gene expression profiles were more numerous during the evolution of lecithotrophy than during the persistence of planktotrophy, and that genes with derived expression profiles in the lecithotroph displayed specific characteristics as a group that are consistent with the dramatically altered developmental program in this species. Compared to the transcriptome, changes in gene expression profiles within the GRN were even more pronounced in the lecithotroph. We found evidence for conservation and likely divergence of particular GRN regulatory interactions in the lecithotroph, as well as significant changes in the expression of genes with known roles in larval skeletogenesis. We further use coexpression analysis to identify genes of unknown function that may contribute to both conserved and derived developmental traits between species. Collectively, our results indicate that distinct evolutionary processes operate on gene expression during periods of life history conservation and periods of life history divergence, and that this contrast is even more pronounced within the GRN than across the transcriptome as a whole
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Comparative clustering strategy reveals cases of expression profile conservation and change within a phylogenetic framework.
2016Co-Authors: Jennifer W. Israel, Rudolf A Raff, Maria Byrne, Megan L. Martik, Elizabeth C. Raff, David R. Mcclay, Gregory A WrayAbstract:(A) Cluster centroids identified in the outgroup L. variegatus are shown (S2 Data), along with the number of genes in each species that were assigned to a given cluster. Green = L. variegatus, blue = H. tuberculata, and purple = H. erythrogramma. The x-axis represents developmental time, and the y-axis represents expression change. (B) Comparative clustering strategy identifies genes that exhibit the same expression profile among all three species (conservation), differ among all three species (divergence), differ between L. variegatus and the Heliocidaris species (genus-level change), or change specifically along a particular branch of the phylogeny (cluster jump in H. tuberculata or H. erythrogramma). (C) Using a comparative clustering strategy (see 2B and Methods), we characterized expression profile divergence (white, 29.8%), conservation (dark grey, 19.1%), and genus-level change (light grey, 19.8%) across the transcriptome. We also detected branch-specific change in H. tuberculata (blue, 13.5%) and H. erythrogramma (purple, 17.8%) (S1 Table).
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Axial patterning of the pentaradial adult echinoderm body plan
Development Genes and Evolution, 2009Co-Authors: Sharon B. Minsuk, Mary E. Andrews, F. Rudolf Turner, Rudolf A RaffAbstract:Adult echinoderms possess a highly diverged, pentaradial body plan. Developmental mechanisms underlying this body plan are completely unknown, but are critical in understanding how echinoderm pentamery evolved from bilateral ancestors. These mechanisms are difficult to study in indirect-developing species; in this study, we use the direct-developing sea urchin Heliocidaris erythrogramma , whose accelerated adult development can be perturbed by NiCl_2. We introduce a new nomenclature for the adult echinoderm axes to facilitate discussion of the radially symmetric body plan and the events required to pattern it. In sea urchins, the adult oral–aboral axis is often conflated with the long axes of the five rays; we identify these as distinct body axes, the proximodistal (PD). In addition, we define a circular axis, the circumoral (CO), along which the division into five sectors occurs. In NiCl_2-treated larvae, aspects of normal PD pattern were retained, but CO pattern was abolished. Milder treatments resulted in relatively normal juveniles ranging from biradial to decaradial. NiCl_2 treatment had no effect either on mesodermal morphology or on the ectodermal gene expression response to an inductive mesodermal signal. This suggests that the mesoderm does not mediate the disruption of CO patterning by NiCl_2. In contrast, mesodermal signaling may explain the presence of PD pattern in treated larvae. However, variations in appendage pattern suggest that ectodermal signals are also required. We conclude that CO patterning in both germ layers is dependent on ectodermal events and PD patterning is controlled by mutual ectoderm–mesoderm signaling.
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Morphogenetic mechanisms of coelom formation in the direct-developing sea urchin Heliocidaris erythrogramma
Development Genes and Evolution, 2009Co-Authors: Margaret S. Smith, Steve Collins, Rudolf A RaffAbstract:Indirect development via a feeding pluteus larva represents the ancestral mode of sea urchin development. However, some sea urchin species exhibit a derived form of development, called direct development, in which features of the feeding larva are replaced by accelerated development of the adult. A major difference between these two developmental modes is the timing of the formation of the left coelom and initiation of adult development. These processes occur much earlier in developmental and absolute time in direct developers and may be underlain by changes in morphogenetic processes. In this study, we explore whether differences in the cellular mechanisms responsible for the development of the left coelom and adult structures are associated with the change in the timing of their formation in the direct-developing sea urchin Heliocidaris erythrogramma . We present evidence that left coelom formation in H. erythrogramma , which differs in major aspects of coelom formation in indirect developers, is not a result of cell division. Further, we demonstrate that subsequent development of adult structures requires cell division.
Byrne Maria - One of the best experts on this subject based on the ideXlab platform.
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Effects of marine heatwave conditions across the metamorphic transition to the juvenile sea urchin (Heliocidaris erythrogramma)
'Elsevier BV', 2021Co-Authors: Gall, Mailie L., Holmes, Sebastian P., Campbell Hamish, Byrne MariaAbstract:For short development species, like the sea urchin Heliocidaris erythrogramma, the entire planktonic duration can be impacted by marine heatwaves (MHW). Developmental thermal tolerance of this species through metamorphosis was investigated over a broad range (7.6–28.0 ◦C), including temperatures across its distribution and MHW conditions. In controls (19.5–21.0 ◦C), 80% of individuals developed to metamorphosis at day 5, doubling to 10 days at 14.0 ◦C. The thermal range (14.4–21.2 ◦C) of metamorphosis on day 7 reflected the realised thermal niche with 25.9 ◦C the upper temperature for success (T40). By day 10, juvenile tolerance narrowed to the local range (16.2–19.0 ◦C), similar to levels tolerated by adults, indicating negative carryover effects across the metamorphic transition. Without phenotypic adjustment or adaptation, regional warming will be detrimental, although populations may be sustained by thermotolerant offspring. Our results show the importance of the metamorphic transition in understanding the cumulative sensitivity of species to MHW
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Microbiome reduction and endosymbiont gain from a switch in sea urchin life history
'Proceedings of the National Academy of Sciences', 2021Co-Authors: Carrier, Tyler J., Byrne Maria, Wray, Gregory A., Leigh, Brittany A., Deaker, Dione J., Devens, Hannah R., Bordenstein, Seth R., Reitzel, Adam M.Abstract:Animal gastrointestinal tracts harbor a microbiome that is integral to host function, yet species from diverse phyla have evolved a reduced digestive system or lost it completely. Whether such changes are associated with alterations in the diversity and/or abundance of the microbiome remains an untested hypothesis in evolutionary symbiosis. Here, using the life history transition from planktotrophy (feeding) to lecithotrophy (nonfeeding) in the sea urchin Heliocidaris, we demonstrate that the lack of a functional gut corresponds with a reduction in microbial community diversity and abundance as well as the association with a diet-specific microbiome. We also determine that the lecithotroph vertically transmits a Rickettsiales that may complement host nutrition through amino acid biosynthesis and influence host reproduction. Our results indicate that the evolutionary loss of a functional gut correlates with a reduction in the microbiome and the association with an endosymbiont. Symbiotic transitions can therefore accompany life history transitions in the evolution of developmental strategies
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Seawater carbonate chemistry and sea urchin reproductive performance
PANGAEA, 2020Co-Authors: Smith, Kathryn E, Byrne Maria, Deaker Dione, Hird, Cameron M, Nielson Clara, Wilson-mcneal Alice, Lewis, Ceri NAbstract:Ocean acidification (OA) is predicted to be a major driver of ocean biodiversity change. At projected rates of change, sensitive marine taxa may not have time to adapt. Their persistence may depend on pre-existing inter-individual variability. We investigated individual male reproductive performance under present-day and OA conditions using two representative broadcast spawners, the sea urchins Lytechinus pictus and Heliocidaris erythrogramma. Under the non-competitive individual ejaculate scenario, we examined sperm functional parameters (e.g. swimming speed, motility) and their relationship with fertilization success under current and near-future OA conditions. Significant inter-individual differences in almost every parameter measured were identified. Importantly, we observed strong inverse relationships between individual fertilization success rate under current conditions and change in fertilization success under OA. Individuals with a high fertilization success under current conditions had reduced fertilization under OA, while individuals with a low fertilization success under current conditions improved. Change in fertilization success ranged from −67% to +114% across individuals. Our results demonstrate that while average population fertilization rates remain similar under OA and present-day conditions, the contribution by different males to the population significantly shifts, with implications for how selection will operate in a future ocean
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Gadolinium toxicity perturbs expression of skeletogenic genes, calcium uptake and larval development in phylogenetically distant sea urchin species
'Elsevier BV', 2018Co-Authors: Martino Chiara, Costa Caterina, Carmela Roccheri Maria, Koop Demian, Scudiero Rosaria, Byrne MariaAbstract:Chelates of Gadolinium (Gd), a lanthanide metal, are employed as contrast agents for magnetic resonance imaging and are released into the aquatic environment where they are an emerging contaminant. We studied the effects of environmentally relevant Gd concentrations on the development of two phylogenetically and geographically distant sea urchin species: the Mediterranean Paracentrotus lividus and the Australian Heliocidaris tuberculata. We found a general delay of embryo development at 24 h post-fertilization, and a strong inhibition of skeleton growth at 48 h. Total Gd and Ca content in the larvae showed a time- and concentration-dependent increase in Gd, in parallel with a reduction in Ca. To investigate the impact of Gd on the expression of genes involved in the regulation of skeletogenesis, we performed comparative RT-PCR analysis and found a misregulation of several genes involved in the skeletogenic and left-right axis specification gene regulatory networks. Species-specific differences in the biomineralization response were evident, likely due to differences in the skeletal framework of the larvae and the amount of biomineral produced. Our results highlight the hazard of Gd for marine organisms
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Raw Data
2016Co-Authors: Brothers, Cecilia J., Harianto Januar, Mcclintock, James B., Byrne MariaAbstract:Raw data set for coelomocyte counts and concentrations, phagocytic activity, and bacterial survival indices after sea urchins (Heliocidaris erythrogramma) were exposed to temperature and pH conditions for 1, 15, and 30 days
Gregory A Wray - One of the best experts on this subject based on the ideXlab platform.
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embryo microinjection of the lecithotrophic sea urchin Heliocidaris erythrogramma
Journal of Biological Methods, 2019Co-Authors: Allison Edgar, Maria Byrne, Gregory A WrayAbstract:Microinjection is a common embryological technique used for many types of experiments, including lineage tracing, manipulating gene expression, or genome editing. Injectable reagents include mRNA overexpression, mis-expression, or dominant-negative experiments to examine a gene of interest, a morpholino antisense oligo to prevent translation of an mRNA or spliceoform of interest and CRISPR-Cas9 reagents. Thus, the technique is broadly useful for basic embryological studies, constructing gene regulatory networks, and directly testing hypotheses about cis-regulatory and coding sequence changes underlying the evolution of development. However, the methods for microinjection in typical planktotrophic marine invertebrates may not work well in the highly modified eggs and embryos of lecithotrophic species. This protocol is optimized for the lecithotrophic sea urchin Heliocidaris erythrogramma.
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a comparative analysis of egg provisioning using mass spectrometry during rapid life history evolution in sea urchins
Evolution & Development, 2019Co-Authors: Phillip L Davidson, Maria Byrne, Will J Thompson, Matthew W Foster, Arthur M Moseley, Gregory A WrayAbstract:A dramatic life history switch that has evolved numerous times in marine invertebrates is the transition from planktotrophic (feeding) to lecithotrophic (nonfeeding) larval development-an evolutionary tradeoff with many important developmental and ecological consequences. To attain a more comprehensive understanding of the molecular basis for this switch, we performed untargeted lipidomic and proteomic liquid chromatography-tandem mass spectrometry on eggs and larvae from three sea urchin species: the lecithotroph Heliocidaris erythrogramma, the closely related planktotroph Heliocidaris tuberculata, and the distantly related planktotroph Lytechinus variegatus. We identify numerous molecular-level changes possibly associated with the evolution of lecithotrophy in H. erythrogramma. We find the massive lipid stores of H. erythrogramma eggs are largely composed of low-density, diacylglycerol ether lipids that, contrary to expectations, appear to support postmetamorphic development and survivorship. Rapid premetamorphic development in this species may instead be powered by upregulated carbohydrate metabolism or triacylglycerol metabolism. We also find proteins involved in oxidative stress regulation are upregulated in H. erythrogramma eggs, and apoB-like lipid transfer proteins may be important for echinoid oogenic nutrient provisioning. These results demonstrate how mass spectrometry can enrich our understanding of life history evolution and organismal diversity by identifying specific molecules associated with distinct life history strategies and prompt new hypotheses about how and why these adaptations evolve.
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expression of genes and proteins of the pax six eya dach network in the metamorphic sea urchin insights into development of the enigmatic echinoderm body plan and sensory structures
Developmental Dynamics, 2018Co-Authors: Maria Byrne, Valerie B Morris, Demian Koop, Juanita Chui, Gregory A Wray, Paula CisternasAbstract:Background: Photoreception-associated genes of the Pax-Six-Eya-Dach network (PSEDN) are deployed for many roles in addition to photoreception development. In this first study of PSEDN genes during development of the pentameral body in sea urchins, we investigated their spatial expression in Heliocidaris erythrogramma. Results: Expression of PSEDN genes in the hydrocoele of early (Dach, Eya, Six1/2) and/or late (Pax6, Six3/6) larvae, and the five hydrocoele lobes, the first morphological expression of pentamery, supports a role in body plan development. Pax6, Six1/2 and Six3/6 were localized to the primary and/or secondary podia and putative sensory/neuronal cells. Six1/2 and Six3/6 were expressed in the neuropil region in the terminal disc of the podia. Dach was localized to spines. Sequential up regulation of gene expression as new podia and spines formed was evident. Rhabdomeric opsin and pax6 protein were localized to cells in the primary podia and spines. Conclusion: Our results support roles for PSEDN genes in development of the pentameral body plan, contributing to our understanding of how the most unusual body plan in the Bilateria may have evolved. Development of sensory cells within the Pax-Six expression field is consistent with the role of these genes in sensory cell development in diverse species. This article is protected by copyright. All rights reserved.
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nodal and bmp expression during the transition to pentamery in the sea urchin Heliocidaris erythrogramma insights into patterning the enigmatic echinoderm body plan
BMC Developmental Biology, 2017Co-Authors: Demian Koop, Valerie B Morris, Paula Cisternas, Gregory A Wray, Dario Strbenac, Jean Yee Hwa Yang, Maria ByrneAbstract:The molecular mechanisms underlying the development of the unusual echinoderm pentameral body plan and their likeness to mechanisms underlying the development of the bilateral plans of other deuterostomes are of interest in tracing body plan evolution. In this first study of the spatial expression of genes associated with Nodal and BMP2/4 signalling during the transition to pentamery in sea urchins, we investigate Heliocidaris erythrogramma, a species that provides access to the developing adult rudiment within days of fertilization. BMP2/4, and the putative downstream genes, Six1/2, Eya, Tbx2/3 and Msx were expressed in the earliest morphological manifestation of pentamery during development, the five hydrocoele lobes. The formation of the vestibular ectoderm, the specialized region overlying the left coelom that forms adult ectoderm, involved the expression of putative Nodal target genes Chordin, Gsc and BMP2/4 and putative BMP2/4 target genes Dlx, Msx and Tbx. The expression of Nodal, Lefty and Pitx2 in the right ectoderm, and Pitx2 in the right coelom, was as previously observed in other sea urchins. That genes associated with Nodal and BMP2/4 signalling are expressed in the hydrocoele lobes, indicates that they have a role in the developmental transition to pentamery, contributing to our understanding of how the most unusual body plan in the Bilateria may have evolved. We suggest that the Nodal and BMP2/4 signalling cascades might have been duplicated or split during the evolution to pentamery.
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Gene expression during sea urchin development reflects known phylogenetic relationships between species.
2016Co-Authors: Jennifer W. Israel, Rudolf A Raff, Maria Byrne, Megan L. Martik, Elizabeth C. Raff, David R. Mcclay, Gregory A WrayAbstract:(A) Our study includes three sea urchin species: the sister species H. tuberculata (planktotroph) and H. erythrogramma (lecithotroph), which diverged approximately 5 Myr, and an outgroup species L. variegatus (planktotroph), which diverged approximately 35–45 Myr ago [44, 50]. (B) Our developmental time course includes seven stages across each species, from unfertilized eggs to early larvae. (C) Principal component (PC) analysis of gene expression (S1 Data). PC1 explains 36% of the overall variation and clearly separated early (egg through 32-cell stage) from later developmental stages (blastula through early larva), whereas PC2 separated L. variegatus from the two Heliocidaris species, corresponding to their phylogenetic relationships.
Andrew R Davis - One of the best experts on this subject based on the ideXlab platform.
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unshelled abalone and corrupted urchins development of marine calcifiers in a changing ocean
Proceedings of The Royal Society B: Biological Sciences, 2011Co-Authors: Maria Byrne, Symon A Dworjanyn, Melanie Ho, Eunice Wong, Natalie A Soars, Paulina Selvakumaraswamy, Hannah Shepardbrennand, Andrew R DavisAbstract:The most fragile skeletons produced by benthic marine calcifiers are those that larvae and juveniles make to support their bodies. Ocean warming, acidification, decreased carbonate saturation and their interactive effects are likely to impair skeletogenesis. Failure to produce skeleton in a changing ocean has negative implications for a diversity of marine species. We examined the interactive effects of warming and acidification on an abalone (Haliotis coccoradiata) and a sea urchin (Heliocidaris erythrogramma) reared from fertilization in temperature and pH/pCO2 treatments in a climatically and regionally relevant setting. Exposureofectodermal(abalone)andmesodermal(echinoid)calcifyingsystemstowarming(þ28Cto 48C) and acidification (pH 7.6‐7.8) resulted in unshelled larvae and abnormal juveniles. Haliotis development was most sensitive with no interaction between stressors. For Heliocidaris, the percentage of normal juveniles decreased in response to both stressors, although a þ28C warming diminished the negative effect of low pH. The number of spines produced decreased with increasing acidification/pCO2, and the interactive effect between stressors indicated that a þ28C warming reduced the negative effects of low pH. At þ48C, the developmental thermal tolerance was breached. Our results show that projected near-future climate change will have deleterious effects on development with differences in vulnerability in the two species.
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temperature but not ph compromises sea urchin fertilization and early development under near future climate change scenarios
Proceedings of The Royal Society B: Biological Sciences, 2009Co-Authors: Maria Byrne, Symon A Dworjanyn, Melanie Ho, Paulina Selvakumaraswamy, Hong D Nguyen, Andrew R DavisAbstract:Global warming is causing ocean warming and acidification. The distribution of Heliocidaris erythrogramma coincides with the eastern Australia climate change hot spot, where disproportionate warming makes marine biota particularly vulnerable to climate change. In keeping with near-future climate change scenarios, we determined the interactive effects of warming and acidification on fertilization and development of this echinoid. Experimental treatments (20–26°C, pH 7.6–8.2) were tested in all combinations for the ‘business-as-usual’ scenario, with 20°C/pH 8.2 being ambient. Percentage of fertilization was high (>89%) across all treatments. There was no difference in percentage of normal development in any pH treatment. In elevated temperature conditions, +4°C reduced cleavage by 40 per cent and +6°C by a further 20 per cent. Normal gastrulation fell below 4 per cent at +6°C. At 26°C, development was impaired. As the first study of interactive effects of temperature and pH on sea urchin development, we confirm the thermotolerance and pH resilience of fertilization and embryogenesis within predicted climate change scenarios, with negative effects at upper limits of ocean warming. Our findings place single stressor studies in context and emphasize the need for experiments that address ocean warming and acidification concurrently. Although ocean acidification research has focused on impaired calcification, embryos may not reach the skeletogenic stage in a warm ocean.