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NCBI: db=pubmed; Term=(((((((((echinoderm) AND developmental biology) OR strongylocentrotus purpuratus) OR patiria miniata) OR lytechinus variegatus) OR eucidaris tribuloides) OR parastichopus parvimensis) OR ophiothrix apiculata) OR allocentrotus fragilis) OR strongylocentrotus franciscanus AND ( ( Humans[Mesh] OR Animals[Mesh:noexp] ) ) AND ("last 5 years"[PDat])
Updated: 16 hours 17 min ago

Environmental risk assessment of triclosan and ibuprofen in marine sediments using individual and sub-individual endpoints.

Sat, 01/20/2018 - 13:45
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Environmental risk assessment of triclosan and ibuprofen in marine sediments using individual and sub-individual endpoints.

Environ Pollut. 2018 Jan;232:274-283

Authors: Pusceddu FH, Choueri RB, Pereira CDS, Cortez FS, Santos DRA, Moreno BB, Santos AR, Rogero JR, Cesar A

Abstract
The guidelines for the Environmental Risk Assessment (ERA) of pharmaceuticals and personal care products (PPCP) recommend the use of standard ecotoxicity assays and the assessment of endpoints at the individual level to evaluate potential effects of PPCP on biota. However, effects at the sub-individual level can also affect the ecological fitness of marine organisms chronically exposed to PPCP. The aim of the current study was to evaluate the environmental risk of two PPCP in marine sediments: triclosan (TCS) and ibuprofen (IBU), using sub-individual and developmental endpoints. The environmental levels of TCS and IBU were quantified in marine sediments from the vicinities of the Santos submarine sewage outfall (Santos Bay, São Paulo, Brazil) at 15.14 and 49.0 ng g-1, respectively. A battery (n = 3) of chronic bioassays (embryo-larval development) with a sea urchin (Lytechinus variegatus) and a bivalve (Perna perna) were performed using two exposure conditions: sediment-water interface and elutriates. Moreover, physiological stress through the Neutral Red Retention Time Assay (NRRT) was assessed in the estuarine bivalve Mytella charruana exposed to TCS and IBU spiked sediments. These compounds affected the development of L. variegatus and P. perna (75 ng g-1 for TCS and 15 ng g-1 for IBU), and caused a significant decrease in M. charruana lysosomal membrane stability at environmentally relevant concentrations (0.08 ng g-1 for TCS and 0.15 ng g-1 for IBU). Chemical and ecotoxicological data were integrated and the risk quotient estimated for TCS and IBU were higher than 1.0, indicating a high environmental risk of these compounds in sediments. These are the first data of sediment risk assessment of pharmaceuticals and personal care products of Latin America. In addition, the results suggest that the ERA based only on individual-level and standard toxicity tests may overlook other biological effects that can affect the health of marine organisms exposed to PPCP.

PMID: 28958726 [PubMed - indexed for MEDLINE]

Categories: pubmed

Evolutionary Proteomics Uncovers Ancient Associations of Cilia with Signaling Pathways.

Thu, 01/18/2018 - 13:44
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Evolutionary Proteomics Uncovers Ancient Associations of Cilia with Signaling Pathways.

Dev Cell. 2017 12 18;43(6):744-762.e11

Authors: Sigg MA, Menchen T, Lee C, Johnson J, Jungnickel MK, Choksi SP, Garcia G, Busengdal H, Dougherty GW, Pennekamp P, Werner C, Rentzsch F, Florman HM, Krogan N, Wallingford JB, Omran H, Reiter JF

Abstract
Cilia are organelles specialized for movement and signaling. To infer when during evolution signaling pathways became associated with cilia, we characterized the proteomes of cilia from sea urchins, sea anemones, and choanoflagellates. We identified 437 high-confidence ciliary candidate proteins conserved in mammals and discovered that Hedgehog and G-protein-coupled receptor pathways were linked to cilia before the origin of bilateria and transient receptor potential (TRP) channels before the origin of animals. We demonstrated that candidates not previously implicated in ciliary biology localized to cilia and further investigated ENKUR, a TRP channel-interacting protein identified in the cilia of all three organisms. ENKUR localizes to motile cilia and is required for patterning the left-right axis in vertebrates. Moreover, mutation of ENKUR causes situs inversus in humans. Thus, proteomic profiling of cilia from diverse eukaryotes defines a conserved ciliary proteome, reveals ancient connections to signaling, and uncovers a ciliary protein that underlies development and human disease.

PMID: 29257953 [PubMed - indexed for MEDLINE]

Categories: pubmed

First Morphological and Molecular Evidence of the Negative Impact of Diatom-Derived Hydroxyacids on the Sea Urchin Paracentrotus lividus.

Thu, 01/18/2018 - 13:44
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First Morphological and Molecular Evidence of the Negative Impact of Diatom-Derived Hydroxyacids on the Sea Urchin Paracentrotus lividus.

Toxicol Sci. 2016 Jun;151(2):419-33

Authors: Varrella S, Romano G, Ruocco N, Ianora A, Bentley MG, Costantini M

Abstract
Oxylipins (including polyunsaturated aldehydes [PUAs], hydoxyacids, and epoxyalcohols) are the end-products of a lipoxygenase/hydroperoxide lyase metabolic pathway in diatoms. To date, very little information is available on oxylipins other than PUAs, even though they represent the most common oxylipins produced by diatoms. Here, we report, for the first time, on the effects of 2 hydroxyacids, 5- and 15-HEPE, which have never been tested before, using the sea urchin Paracentrotus lividus as a model organism. We show that HEPEs do induce developmental malformations but at concentrations higher when compared with PUAs. Interestingly, HEPEs also induced a marked developmental delay in sea urchin embryos, which has not hitherto been reported for PUAs. Recovery experiments revealed that embryos do not recover following treatment with HEPEs. Finally, we report the expression levels of 35 genes (involved in stress, development, differentiation, skeletogenesis, and detoxification processes) to identify the molecular targets affected by HEPEs. We show that the 2 HEPEs have very few common molecular targets, specifically affecting different classes of genes and at different times of development. In particular, 15-HEPE switched on fewer genes than 5-HEPE, upregulating mainly stress-related genes at a later pluteus stage of development. 5-HEPE was stronger than 15-HEPE, targeting 24 genes, mainly at the earliest stages of embryo development (at the blastula and swimming blastula stages). These findings highlight the differences between HEPEs and PUAs and also have important ecological implications because many diatom species do not produce PUAs, but rather these other chemicals are derived from the oxidation of fatty acids.

PMID: 26984781 [PubMed - indexed for MEDLINE]

Categories: pubmed

Live Imaging of Centriole Dynamics by Fluorescently Tagged Proteins in Starfish Oocyte Meiosis.

Sat, 01/13/2018 - 13:40
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Live Imaging of Centriole Dynamics by Fluorescently Tagged Proteins in Starfish Oocyte Meiosis.

Methods Mol Biol. 2016;1457:145-66

Authors: Borrego-Pinto J, Somogyi K, Lénárt P

Abstract
High throughput DNA sequencing, the decreasing costs of DNA synthesis, and universal techniques for genetic manipulation have made it much easier and quicker to establish molecular tools for any organism than it has been 5 years ago. This opens a great opportunity for reviving "nonconventional" model organisms, which are particularly suited to study a specific biological process and many of which have already been established before the era of molecular biology. By taking advantage of transcriptomics, in particular, these systems can now be easily turned into full fetched models for molecular cell biology.As an example, here we describe how we established molecular tools in the starfish Patiria miniata, which has been a popular model for cell and developmental biology due to the synchronous and rapid development, transparency, and easy handling of oocytes, eggs, and embryos. Here, we detail how we used a de novo assembled transcriptome to produce molecular markers and established conditions for live imaging to investigate the molecular mechanisms underlying centriole elimination-a poorly understood process essential for sexual reproduction of animal species.

PMID: 27557579 [PubMed - indexed for MEDLINE]

Categories: pubmed

Regeneration in bipinnaria larvae of the bat star Patiria miniata induces rapid and broad new gene expression.

Sat, 01/13/2018 - 13:40
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Regeneration in bipinnaria larvae of the bat star Patiria miniata induces rapid and broad new gene expression.

Mech Dev. 2016 Nov;142:10-21

Authors: Oulhen N, Heyland A, Carrier TJ, Zazueta-Novoa V, Fresques T, Laird J, Onorato TM, Janies D, Wessel G

Abstract
BACKGROUND: Some metazoa have the capacity to regenerate lost body parts. This phenomenon in adults has been classically described in echinoderms, especially in sea stars (Asteroidea). Sea star bipinnaria larvae can also rapidly and effectively regenerate a complete larva after surgical bisection. Understanding the capacity to reverse cell fates in the larva is important from both a developmental and biomedical perspective; yet, the mechanisms underlying regeneration in echinoderms are poorly understood.
RESULTS: Here, we describe the process of bipinnaria regeneration after bisection in the bat star Patiria miniata. We tested transcriptional, translational, and cell proliferation activity after bisection in anterior and posterior bipinnaria halves as well as expression of SRAP, reported as a sea star regeneration associated protease (Vickery et al., 2001b). Moreover, we found several genes whose transcripts increased in abundance following bisection, including: Vasa, dysferlin, vitellogenin 1 and vitellogenin 2.
CONCLUSION: These results show a transformation following bisection, especially in the anterior halves, of cell fate reassignment in all three germ layers, with clear and predictable changes. These results define molecular events that accompany the cell fate changes coincident to the regenerative response in echinoderm larvae.

PMID: 27555501 [PubMed - indexed for MEDLINE]

Categories: pubmed

The Power of Simplicity: Sea Urchin Embryos as in Vivo Developmental Models for Studying Complex Cell-to-cell Signaling Network Interactions.

Wed, 01/10/2018 - 13:33
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The Power of Simplicity: Sea Urchin Embryos as in Vivo Developmental Models for Studying Complex Cell-to-cell Signaling Network Interactions.

J Vis Exp. 2017 Feb 16;(120):

Authors: Range RC, Martinez-Bartolomé M, Burr SD

Abstract
Remarkably few cell-to-cell signal transduction pathways are necessary during embryonic development to generate the large variety of cell types and tissues in the adult body form. Yet, each year more components of individual signaling pathways are discovered, and studies indicate that depending on the context there is significant cross-talk among most of these pathways. This complexity makes studying cell-to-cell signaling in any in vivo developmental model system a difficult task. In addition, efficient functional analyses are required to characterize molecules associated with signaling pathways identified from the large data sets generated by next generation differential screens. Here, we illustrate a straightforward method to efficiently identify components of signal transduction pathways governing cell fate and axis specification in sea urchin embryos. The genomic and morphological simplicity of embryos similar to those of the sea urchin make them powerful in vivo developmental models for understanding complex signaling interactions. The methodology described here can be used as a template for identifying novel signal transduction molecules in individual pathways as well as the interactions among the molecules in the various pathways in many other organisms.

PMID: 28287557 [PubMed - indexed for MEDLINE]

Categories: pubmed

Comparative study of three phenoloxidases in the sea cucumber Apostichopus japonicus.

Tue, 12/19/2017 - 13:00
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Comparative study of three phenoloxidases in the sea cucumber Apostichopus japonicus.

Fish Shellfish Immunol. 2017 Aug;67:11-18

Authors: Jiang J, Zhou Z, Dong Y, Chen Z, Sun H, Yang A, Gao S, Su H

Abstract
In order to preliminarily illustrate the functional differences of phenoloxidases (POs) in Apostichopus japonicus, the full-length cDNAs of two POs (named as AjPOⅡ and AjPOⅢ, respectively) were cloned from the coelomocytes of A. japonicus using 3'- and 5'-rapid amplification of cDNA ends method, and combined with the previously acquired full-length cDNA of a laccase-type PO from A. japonicus (Accession No. KF040052, named as AjPOⅠ), the sequence structure and phylogenic status of POs from A. japonicus (AjPOs) were comparatively analyzed, and the transcriptional expression of AjPOs in different tissues, at different developmental stages and after different bacterial challenges was determined with quantitative real-time PCR method. Sequence analysis indicated AjPOⅡ and AjPOⅢ were both laccase-type POs, coincident to the results of phylogenic analysis. Sequence analysis also showed that AjPOⅠ had a transmembrane domain (J. Jiang et al., 2014), AjPOⅡ contained a signal peptide, and AjPOⅢ possessed a signal peptide and a transmembrane domain, implying that three AjPOs might play different roles in immune and physiological processes. Transcriptional expression analysis showed that AjPOⅡ and AjPOⅢ were most abundant in tube feet, while AjPOⅠhad the highest expression level in coelomocytes (J. Jiang et al., 2014), suggesting that AjPOⅠ may be mainly involved in immune response, while AjPOⅡ and AjPOⅢ are probably responsible for other physiological processes in addition to immune response. Besides, three AjPOs were determined to have different expression patterns during organism development and different spectrums of response against bacteria, which further indicated that there might be immune and physiological functional differentiation among three AjPOs.

PMID: 28554836 [PubMed - indexed for MEDLINE]

Categories: pubmed

A key role for foxQ2 in anterior head and central brain patterning in insects.

Thu, 12/07/2017 - 12:49
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A key role for foxQ2 in anterior head and central brain patterning in insects.

Development. 2017 08 15;144(16):2969-2981

Authors: Kitzmann P, Weißkopf M, Schacht MI, Bucher G

Abstract
Anterior patterning of animals is based on a set of highly conserved transcription factors but the interactions within the protostome anterior gene regulatory network (aGRN) remain enigmatic. Here, we identify the red flour beetle Tribolium castaneum ortholog of foxQ2 (Tc-foxQ2) as a novel upstream component of the aGRN. It is required for the development of the labrum and higher order brain structures, namely the central complex and the mushroom bodies. We reveal Tc-foxQ2 interactions by RNAi and heat shock-mediated misexpression. Surprisingly, Tc-foxQ2 and Tc-six3 mutually activate each other, forming a novel regulatory module at the top of the aGRN. Comparisons of our results with those of sea urchins and cnidarians suggest that foxQ2 has acquired more upstream functions in the aGRN during protostome evolution. Our findings expand the knowledge on foxQ2 gene function to include essential roles in epidermal development and central brain patterning.

PMID: 28811313 [PubMed - indexed for MEDLINE]

Categories: pubmed

Parallel embryonic transcriptional programs evolve under distinct constraints and may enable morphological conservation amidst adaptation.

Thu, 12/07/2017 - 12:49
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Parallel embryonic transcriptional programs evolve under distinct constraints and may enable morphological conservation amidst adaptation.

Dev Biol. 2017 10 01;430(1):202-213

Authors: Malik A, Gildor T, Sher N, Layous M, Ben-Tabou de-Leon S

Abstract
Embryonic development evolves by balancing stringent morphological constraints with genetic and environmental variation. The design principle that allows developmental transcriptional programs to conserve embryonic morphology while adapting to environmental changes is still not fully understood. To address this fundamental challenge, we compare developmental transcriptomes of two sea urchin species, Paracentrotus lividus and Strongylocentrotus purpuratus, that shared a common ancestor about 40 million years ago and are geographically distant yet show similar morphology. We find that both developmental and housekeeping genes show highly dynamic and strongly conserved temporal expression patterns. The expression of other gene sets, including homeostasis and response genes, show divergent expression which could result from either evolutionary drift or adaptation to local environmental conditions. The interspecies correlations of developmental gene expressions are highest between morphologically similar developmental time points whereas the interspecies correlations of housekeeping gene expression are high between all the late zygotic time points. Relatedly, the position of the phylotypic stage varies between these two groups of genes: developmental gene expression shows highest conservation at mid-developmental stage, in agreement with the hourglass model while the conservation of housekeeping genes keeps increasing with developmental time. When all genes are combined, the relationship between conservation of gene expression and morphological similarity is partially masked by housekeeping genes and genes with diverged expression. Our study illustrates various transcriptional programs that coexist in the developing embryo and evolve under different constraints. Apparently, morphological constraints underlie the conservation of developmental gene expression while embryonic fitness requires the conservation of housekeeping gene expression and the species-specific adjustments of homeostasis gene expression. The distinct evolutionary forces acting on these transcriptional programs enable the conservation of similar body plans while allowing adaption.

PMID: 28780048 [PubMed - indexed for MEDLINE]

Categories: pubmed

Asymmetric distribution of hypoxia-inducible factor α regulates dorsoventral axis establishment in the early sea urchin embryo.

Thu, 12/07/2017 - 12:49
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Asymmetric distribution of hypoxia-inducible factor α regulates dorsoventral axis establishment in the early sea urchin embryo.

Development. 2017 08 15;144(16):2940-2950

Authors: Chang WL, Chang YC, Lin KT, Li HR, Pai CY, Chen JH, Su YH

Abstract
Hypoxia signaling is an ancient pathway by which animals can respond to low oxygen. Malfunction of this pathway disturbs hypoxic acclimation and can result in various diseases, including cancers. The role of hypoxia signaling in early embryogenesis remains unclear. Here, we show that in the blastula of the sea urchin Strongylocentrotus purpuratus, hypoxia-inducible factor α (HIFα), the downstream transcription factor of the hypoxia pathway, is localized and transcriptionally active on the future dorsal side. This asymmetric distribution is attributable to its oxygen-sensing ability. Manipulations of the HIFα level entrained the dorsoventral axis, as the side with the higher level of HIFα tends to develop into the dorsal side. Gene expression analyses revealed that HIFα restricts the expression of nodal to the ventral side and activates several genes encoding transcription factors on the dorsal side. We also observed that intrinsic hypoxic signals in the early embryos formed a gradient, which was disrupted under hypoxic conditions. Our results reveal an unprecedented role of the hypoxia pathway in animal development.

PMID: 28705895 [PubMed - indexed for MEDLINE]

Categories: pubmed

Extracellular matrix remodeling and matrix metalloproteinases (ajMMP-2 like and ajMMP-16 like) characterization during intestine regeneration of sea cucumber Apostichopus japonicus.

Thu, 12/07/2017 - 12:49
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Extracellular matrix remodeling and matrix metalloproteinases (ajMMP-2 like and ajMMP-16 like) characterization during intestine regeneration of sea cucumber Apostichopus japonicus.

Comp Biochem Physiol B Biochem Mol Biol. 2017 Oct;212:12-23

Authors: Miao T, Wan Z, Sun L, Li X, Xing L, Bai Y, Wang F, Yang H

Abstract
Remodeling of extracellular matrix (ECM) regulated by matrix metalloproteinases (MMPs) is essential for tissue regeneration. In the present study, we used immunohistochemistry (IHC) techniques against ECM components to reveal changes of ECM during intestine regeneration of Apostichopus japonicus. The expression of collagen I and laminin reduced apparently from the eviscerated intestine, while fibronectin exhibited continuous expression in all regeneration stages observed. Meanwhile, we cloned two MMP genes from A. japonicus by RACE PCR. The full-length cDNA of ajMMP-2 like is 2733bp and contains a predicted open reading frame (ORF) of 1716bp encoding 572 amino acids. The full-length cDNA of ajMMP-16 like is 2705bp and contains an ORF of 1452bp encoding 484 amino acids. The predicted protein sequences of each MMP contain two conserved domains, ZnMc_MMP and HX. Homology and phylogenetic analysis revealed that ajMMP-2 like and ajMMP-16 like share high sequence similarity with MMP-2 and MMP-16 from Strongylocentrotus purpuratus, respectively. Then we investigated spatio-temporal expression of ajMMP-2 like and ajMMP-16 like during different regeneration stages by qRT-PCR and IHC. The expression pattern of them showed a roughly opposite trend from that of ECM components. According to our results, a fibronectin-dominate temporary matrix is created in intestine regeneration, and it might provide structural integrity for matrix and promote cell movement. We also hypothesize that ajMMP-2 like and ajMMP-16 like could accelerate cell migration and regulate interaction between ECM components and growth factors. This work provides new evidence of ECM and MMPs involvement in sea cucumber regeneration.

PMID: 28687360 [PubMed - indexed for MEDLINE]

Categories: pubmed

A Model Sea Urchin Spicule Matrix Protein, rSpSM50, Is a Hydrogelator That Modifies and Organizes the Mineralization Process.

Thu, 12/07/2017 - 12:49
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A Model Sea Urchin Spicule Matrix Protein, rSpSM50, Is a Hydrogelator That Modifies and Organizes the Mineralization Process.

Biochemistry. 2017 05 30;56(21):2663-2675

Authors: Jain G, Pendola M, Huang YC, Gebauer D, Evans JS

Abstract
In the purple sea urchin Strongylocentrotus purpuratus, the formation and mineralization of fracture-resistant skeletal elements such as the embryonic spicule require the combinatorial participation of numerous spicule matrix proteins such as SpSM50. However, because of its limited abundance and solubility issues, it has been difficult to pursue extensive in vitro biochemical studies of SpSM50 protein and deduce its role in spicule formation and mineralization. To circumvent these problems, we expressed a tag-free bacterial model recombinant spicule matrix protein, rSpSM50. Bioinformatics and biophysical experiments confirm that rSpSM50 is an intrinsically disordered, aggregation-prone C-type lectin-like domain-containing protein that forms dimensionally and internally heterogeneous protein hydrogels that control the in vitro mineralization process in three ways. The hydrogels (1) kinetically stabilize the aqueous calcium carbonate system against nucleation and thermodynamically destabilize the initially formed ACC in bulk solution, (2) promote and organize faceted single-crystal calcite and polycrystalline vaterite nanoparticles, and (3) promote surface texturing of calcite crystals and induce subsurface nanoporosities and channels within both calcite and vaterite crystals. Many of these features are also common to mollusk shell nacre proteins and the sea urchin spicule matrix glycoprotein, SpSM30B/C, and we conclude that rSpSM50 is a spiculogenesis hydrogelator protein that exhibits traits found in other calcium carbonate mineral-modification proteins.

PMID: 28478667 [PubMed - indexed for MEDLINE]

Categories: pubmed

Characterization and expression analysis of Galnts in developing Strongylocentrotus purpuratus embryos.

Thu, 12/07/2017 - 12:49
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Characterization and expression analysis of Galnts in developing Strongylocentrotus purpuratus embryos.

PLoS One. 2017;12(4):e0176479

Authors: Famiglietti AL, Wei Z, Beres TM, Milac AL, Tran DT, Patel D, Angerer RC, Angerer LM, Tabak LA

Abstract
Mucin-type O-glycosylation is a ubiquitous posttranslational modification in which N-Acetylgalactosamine (GalNAc) is added to the hydroxyl group of select serine or threonine residues of a protein by the family of UDP-GalNAc:Polypeptide N-Acetylgalactosaminyltransferases (GalNAc-Ts; EC 2.4.1.41). Previous studies demonstrate that O-glycosylation plays essential roles in protein function, cell-cell interactions, cell polarity and differentiation in developing mouse and Drosophila embryos. Although this type of protein modification is highly conserved among higher eukaryotes, little is known about this family of enzymes in echinoderms, basal deuterostome relatives of the chordates. To investigate the potential role of GalNAc-Ts in echinoderms, we have begun the characterization of this enzyme family in the purple sea urchin, S. purpuratus. We have fully or partially cloned a total of 13 genes (SpGalnts) encoding putative sea urchin SpGalNAc-Ts, and have confirmed enzymatic activity of five recombinant proteins. Amino acid alignments revealed high sequence similarity among sea urchin and mammalian glycosyltransferases, suggesting the presence of putative orthologues. Structural models underscored these similarities and helped reconcile some of the substrate preferences observed. Temporal and spatial expression of SpGalnt transcripts, was studied by whole-mount in situ hybridization. We found that many of these genes are transcribed early in developing embryos, often with restricted expression to the endomesodermal region. Multicolor fluorescent in situ hybridization (FISH) demonstrated that transcripts encoding SpGalnt7-2 co-localized with both Endo16 (a gene expressed in the endoderm), and Gcm (a gene expressed in secondary mesenchyme cells) at the early blastula stage, 20 hours post fertilization (hpf). At late blastula stage (28 hpf), SpGalnt7-2 message co-expresses with Gcm, suggesting that it may play a role in secondary mesenchyme development. We also discovered that morpholino-mediated knockdown of SpGalnt13 transcripts, results in a deficiency of embryonic skeleton and neurons, suggesting that mucin-type O-glycans play essential roles during embryonic development in S. purpuratus.

PMID: 28448610 [PubMed - indexed for MEDLINE]

Categories: pubmed

New inter-correlated genes targeted by diatom-derived polyunsaturated aldehydes in the sea urchin Paracentrotus lividus.

Thu, 12/07/2017 - 12:49
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New inter-correlated genes targeted by diatom-derived polyunsaturated aldehydes in the sea urchin Paracentrotus lividus.

Ecotoxicol Environ Saf. 2017 Aug;142:355-362

Authors: Ruocco N, Maria Fedele A, Costantini S, Romano G, Ianora A, Costantini M

Abstract
The marine environment is continually subjected to the action of stressors (including natural toxins), which represent a constant danger for benthic communities. In the present work using network analysis we identified ten genes on the basis of associated functions (FOXA, FoxG, GFI-1, nodal, JNK, OneCut/Hnf6, TAK1, tcf4, TCF7, VEGF) in the sea urchin Paracentrotus lividus, having key roles in different processes, such as embryonic development and asymmetry, cell fate specification, cell differentiation and morphogenesis, and skeletogenesis. These genes are correlated with three HUB genes, Foxo, Jun and HIF1A. Real Time qPCR revealed that during sea urchin embryonic development the expression levels of these genes were modulated by three diatom-derived polyunsaturated aldehydes (PUAs), decadienal, heptadienal and octadienal. Our findings show how changes in gene expression levels may be used as an early indicator of stressful conditions in the marine environment. The identification of key genes and the molecular pathways in which they are involved represents a fundamental tool in understanding how marine organisms try to afford protection against toxicants, to avoid deleterious consequences and irreversible damages. The genes identified in this work as targets for PUAs can be considered as possible biomarkers to detect exposure to different environmental pollutants.

PMID: 28437727 [PubMed - indexed for MEDLINE]

Categories: pubmed

Experimental demonstration of a trophic cascade in the Galápagos rocky subtidal: Effects of consumer identity and behavior.

Thu, 12/07/2017 - 12:49
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Experimental demonstration of a trophic cascade in the Galápagos rocky subtidal: Effects of consumer identity and behavior.

PLoS One. 2017;12(4):e0175705

Authors: Witman JD, Smith F, Novak M

Abstract
In diverse tropical webs, trophic cascades are presumed to be rare, as species interactions may dampen top-down control and reduce their prevalence. To test this hypothesis, we used an open experimental design in the Galápagos rocky subtidal that enabled a diverse guild of fish species, in the presence of each other and top predators (sea lions and sharks), to attack two species of sea urchins grazing on benthic algae. Time-lapse photography of experiments on natural and experimental substrates revealed strong species identity effects: only two predator species-blunthead triggerfish (Pseudobalistes naufragium) and finescale triggerfish (Balistes polylepis)-drove a diurnal trophic cascade extending to algae, and they preferred large pencil urchins (Eucidaris galapagensis) over green urchins (Lytechinus semituberculatus). Triggerfish predation effects were strong, causing a 24-fold reduction of pencil urchin densities during the initial 21 hours of a trophic cascade experiment. A trophic cascade was demonstrated for pencil urchins, but not for green urchins, by significantly higher percent cover of urchin-grazed algae in cages that excluded predatory fish than in predator access (fence) treatments. Pencil urchins were more abundant at night when triggerfish were absent, suggesting that this species persists by exploiting a nocturnal predation refuge. Time-series of pencil urchin survivorship further demonstrated per capita interference effects of hogfish and top predators. These interference effects respectively weakened and extended the trophic cascade to a fourth trophic level through behavioral modifications of the triggerfish-urchin interaction. We conclude that interference behaviors capable of modifying interaction strength warrant greater attention as mechanisms for altering top-down control, particularly in speciose food webs.

PMID: 28430794 [PubMed - indexed for MEDLINE]

Categories: pubmed

Sequential Response to Multiple Developmental Network Circuits Encoded in an Intronic cis-Regulatory Module of Sea Urchin hox11/13b.

Thu, 12/07/2017 - 12:49
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Sequential Response to Multiple Developmental Network Circuits Encoded in an Intronic cis-Regulatory Module of Sea Urchin hox11/13b.

Cell Rep. 2017 Apr 11;19(2):364-374

Authors: Cui M, Vielmas E, Davidson EH, Peter IS

Abstract
Gene expression in different spatial domains is often controlled by separate cis-regulatory modules (CRMs), but regulatory states determining CRM activity are not only distinct in space, they also change continuously during developmental time. Here, we systematically analyzed the regulatory sequences controlling hox11/13b expression and identified a single CRM required throughout embryonic gut development. We show that within this CRM, distinct sets of binding sites recognizing Ets, Tcf, and homeodomain transcription factors control the dynamic spatial expression of hox11/13b in each developmental phase. Several binding sites execute multiple, sometimes contradictory, regulatory functions, depending on the temporal and spatial regulatory context. In addition, we identified a nearby second CRM operating in inter-modular AND logic with the first CRM to control hox11/13b expression in hindgut endoderm. Our results suggest a mechanism for continuous gene expression in response to changing developmental network functions that depends on sequential combinatorial regulation of individual CRMs.

PMID: 28402858 [PubMed - indexed for MEDLINE]

Categories: pubmed

Ocean Acidification Reduces Spine Mechanical Strength in Euechinoid but Not in Cidaroid Sea Urchins.

Thu, 12/07/2017 - 12:49
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Ocean Acidification Reduces Spine Mechanical Strength in Euechinoid but Not in Cidaroid Sea Urchins.

Environ Sci Technol. 2017 Apr 04;51(7):3640-3648

Authors: Dery A, Collard M, Dubois P

Abstract
Echinoderms are considered particularly sensitive to ocean acidification (OA) as their skeleton is made of high-magnesium calcite, one of the most soluble forms of calcium carbonate. Recent studies have investigated effects of OA on the skeleton of "classical" sea urchins (euechinoids), but the impact of etching on skeleton mechanical properties is almost unknown. Furthermore, the integrity of the skeleton of cidaroids has never been assessed, although their extracellular fluid is under-saturated with respect to their skeleton, and the skeleton of their primary spines is in direct contact with seawater. In this study, we compared the dissolution of test plates and spines as well as the spine mechanical properties (two-points bending tests) in a cidaroid (Eucidaris tribuloides) and a euechinoid (Tripneustes ventricosus) submitted to a 5 week acidification experiment (pHT of 8.1, 7.7, and 7.4). Test plates of both species were not affected by dissolution. The spines of E. tribuloides showed no mechanical effects at pHSW-T 7.4 despite having traces of corrosion on secondary spines. On the contrary, spines of the T. ventricosus were significantly etched at both pHSW-T 7.7 and 7.4 and their fracture force reduced by 16 to 35%, respectively. This increased brittleness is probably of little significance with regards to predation protection but has consequences in terms of energy allocation.

PMID: 28267915 [PubMed - indexed for MEDLINE]

Categories: pubmed

Multitasking Immune Sp185/333 Protein, rSpTransformer-E1, and Its Recombinant Fragments Undergo Secondary Structural Transformation upon Binding Targets.

Thu, 12/07/2017 - 12:49
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Multitasking Immune Sp185/333 Protein, rSpTransformer-E1, and Its Recombinant Fragments Undergo Secondary Structural Transformation upon Binding Targets.

J Immunol. 2017 Apr 01;198(7):2957-2966

Authors: Lun CM, Bishop BM, Smith LC

Abstract
The purple sea urchin, Strongylocentrotus purpuratus, expresses a diverse immune response protein family called Sp185/333. A recombinant Sp185/333 protein, previously called rSp0032, shows multitasking antipathogen binding ability, suggesting that the protein family mediates a flexible and effective immune response to multiple foreign cells. Bioinformatic analysis predicts that rSp0032 is intrinsically disordered, and its multiple binding characteristic suggests structural flexibility to adopt different conformations depending on the characteristics of the target. To address the flexibility and structural shifting hypothesis, circular dichroism analysis of rSp0032 suggests that it transforms from disordered (random coil) to α helical structure. This structural transformation may be the basis for the strong affinity between rSp0032 and several pathogen-associated molecular patterns. The N-terminal Gly-rich fragment of rSp0032 and the C-terminal His-rich fragment show unique transformations by either intensifying the α helical structure or changing from α helical to β strand depending on the solvents and molecules added to the buffer. Based on these results, we propose a name change from rSp0032 to rSpTransformer-E1 to represent its flexible structural conformations and its E1 element pattern. Given that rSpTransformer-E1 shifts its conformation in the presence of solvents and binding targets and that all Sp185/333 proteins are predicted to be disordered, many or all of these proteins may undergo structural transformation to enable multitasking binding activity toward a wide range of targets. Consequently, we also propose an overarching name change for the entire family from Sp185/333 proteins to SpTransformer proteins.

PMID: 28242650 [PubMed - indexed for MEDLINE]

Categories: pubmed

Transient translational quiescence in primordial germ cells.

Thu, 12/07/2017 - 12:49
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Transient translational quiescence in primordial germ cells.

Development. 2017 04 01;144(7):1201-1210

Authors: Oulhen N, Swartz SZ, Laird J, Mascaro A, Wessel GM

Abstract
Stem cells in animals often exhibit a slow cell cycle and/or low transcriptional activity referred to as quiescence. Here, we report that the translational activity in the primordial germ cells (PGCs) of the sea urchin embryo (Strongylocentrotus purpuratus) is quiescent. We measured new protein synthesis with O-propargyl-puromycin and L-homopropargylglycine Click-iT technologies, and determined that these cells synthesize protein at only 6% the level of their adjacent somatic cells. Knockdown of translation of the RNA-binding protein Nanos2 by morpholino antisense oligonucleotides, or knockout of the Nanos2 gene by CRISPR/Cas9 resulted in a significant, but partial, increase (47%) in general translation specifically in the PGCs. We found that the mRNA of the translation factor eEF1A is excluded from the PGCs in a Nanos2-dependent manner, a consequence of a Nanos/Pumilio response element (PRE) in its 3'UTR. In addition to eEF1A, the cytoplasmic pH of the PGCs appears to repress translation and simply increasing the pH also significantly restores translation selectively in the PGCs. We conclude that the PGCs of this sea urchin institute parallel pathways to quiesce translation thoroughly but transiently.

PMID: 28235822 [PubMed - indexed for MEDLINE]

Categories: pubmed

Melanotransferrin: New Homolog Genes and Their Differential Expression during Intestinal Regeneration in the Sea Cucumber Holothuria glaberrima.

Thu, 12/07/2017 - 12:49
Related Articles

Melanotransferrin: New Homolog Genes and Their Differential Expression during Intestinal Regeneration in the Sea Cucumber Holothuria glaberrima.

J Exp Zool B Mol Dev Evol. 2017 May;328(3):259-274

Authors: Hernández-Pasos J, Valentín-Tirado G, García-Arrarás JE

Abstract
Melanotransferrin (MTf) is a protein associated with oncogenetic, developmental, and immune processes which function remains unclear. The MTf gene has been reported in numerous vertebrate and invertebrate species, including echinoderms. We now report the finding of four different MTfs in the transcriptome of the sea cucumber Holothuria glaberrima. Sequence studies and phylogenetic analyses were done to ascertain the similarities among the putative proteins and their relationship with other transferrin family members. The genes were shown to be differentially expressed in various holothurian organs and to respond differently when the animals were challenged with the immune system activator lipopolysaccharide (LPS). Moreover, the four genes were found to be highly overexpressed during the early stages of intestinal regeneration. The finding of four different genes in the holothurian is particularly surprising, because only one MTf gene has been reported in all other animal species sequenced to date. This finding, combined with the increase expression during intestinal regeneration, suggests a new possible function of MTf in organ regenerative processes.

PMID: 28229527 [PubMed - indexed for MEDLINE]

Categories: pubmed

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