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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: 15 hours 9 min ago

Terminal alpha-d-mannosides are critical during sea urchin gastrulation.

Sat, 06/10/2017 - 22:08
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Terminal alpha-d-mannosides are critical during sea urchin gastrulation.

Zygote. 2016 Oct;24(5):775-82

Authors: Aleksanyan H, Liang J, Metzenberg S, Oppenheimer SB

Abstract
The sea urchin embryo is a United States National Institutes of Health (NIH) designated model system to study mechanisms that may be involved in human health and disease. In order to examine the importance of high-mannose glycans and polysaccharides in gastrulation, Lytechinus pictus embryos were incubated with Jack bean α-mannosidase (EC 3.2.1.24), an enzyme that cleaves terminal mannose residues that have α1-2-, α1-3-, or α1-6-glycosidic linkages. The enzyme treatment caused a variety of morphological deformations in living embryos, even with α-mannosidase activities as low as 0.06 U/ml. Additionally, formaldehyde-fixed, 48-hour-old L. pictus embryos were microdissected and it was demonstrated that the adhesion of the tip of the archenteron to the roof of the blastocoel in vitro is abrogated by treatment with α-mannosidase. These results suggest that terminal mannose residues are involved in the adhesion between the archenteron and blastocoel roof, perhaps through a lectin-like activity that is not sensitive to fixation.

PMID: 27189235 [PubMed - indexed for MEDLINE]

Categories: pubmed

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

Fri, 06/09/2017 - 22:08
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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

TGF-β sensu stricto signaling regulates skeletal morphogenesis in the sea urchin embryo.

Wed, 06/07/2017 - 22:06
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TGF-β sensu stricto signaling regulates skeletal morphogenesis in the sea urchin embryo.

Dev Biol. 2017 Jan 15;421(2):149-160

Authors: Sun Z, Ettensohn CA

Abstract
Cell-cell signaling plays a prominent role in the formation of the embryonic skeleton of sea urchins, but the mechanisms are poorly understood. In the present study, we uncover an essential role for TGF-β sensu stricto signaling in this process. We show that TgfbrtII, a type II receptor dedicated to signaling through TGF-β sensu stricto, is expressed selectively in skeletogenic primary mesenchyme cells (PMCs) during skeleton formation. Morpholino (MO) knockdowns and studies with a specific TgfbrtII inhibitor (ITD-1) in both S. purpuratus and Lytechinus variegatus embryos show that this receptor is required for biomineral deposition. We provide pharmacological evidence that Alk4/5/7 is the cognate TGF-β type I receptor that pairs with TgfbrtII and show by inhibitor treatments of isolated micromeres cultured in vitro that both Alk4/5/7 and TgfbrtII function cell-autonomously in PMCs. Gene expression and gene knockdown studies suggest that TGF-β sensu stricto may be the ligand that interacts with TgfbrtII and support the view that this TGF-β superfamily ligand provides an essential, permissive cue for skeletogenesis, although it is unlikely to provide spatial patterning information. Taken together, our findings reveal that this model morphogenetic process involves an even more diverse suite of cell signaling pathways than previously appreciated and show that PMCs integrate a complex set of both generalized and spatially localized cues in assembling the endoskeleton.

PMID: 27955944 [PubMed - indexed for MEDLINE]

Categories: pubmed

MAPK/ERK activity is required for the successful progression of mitosis in sea urchin embryos.

Wed, 06/07/2017 - 22:06
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MAPK/ERK activity is required for the successful progression of mitosis in sea urchin embryos.

Dev Biol. 2017 Jan 15;421(2):194-203

Authors: Mulner-Lorillon O, Chassé H, Morales J, Bellé R, Cormier P

Abstract
Using sea urchin embryos, we demonstrate that the MEK/MAPK/ERK cascade is essential for the proper progression of the cell cycle. Activation of a limited fraction of MAPK/ERK is required between S-phase and M-phase. Neither DNA replication nor CDK1 activation are impacted by the inhibition of this small active MAPK/ERK fraction. Nonetheless, the chromatin and spindle organisations are profoundly altered. Early morphological disorders induced by the absence of MAPK/ERK activation are correlated with an important inhibition of global protein synthesis and modification in the cyclin B accumulation profile. After appearance of morphological disorders, there is an increase in the level of the inhibitor of protein synthesis, 4E-BP, and, ultimately, an activation of the spindle checkpoint. Altogether, our results suggest that MAPK/ERK activity is required for the synthesis of (a) protein(s) implicated in an early step of chromatin /microtubule attachment. If this MAPK/ERK-dependent step is not achieved, the cell activates a new checkpoint mechanism, involving the reappearance of 4E-BP that maintains a low level of protein translation, thus saving cellular energy.

PMID: 27913220 [PubMed - indexed for MEDLINE]

Categories: pubmed

KirrelL, a member of the Ig-domain superfamily of adhesion proteins, is essential for fusion of primary mesenchyme cells in the sea urchin embryo.

Wed, 06/07/2017 - 22:06
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KirrelL, a member of the Ig-domain superfamily of adhesion proteins, is essential for fusion of primary mesenchyme cells in the sea urchin embryo.

Dev Biol. 2017 Jan 15;421(2):258-270

Authors: Ettensohn CA, Dey D

Abstract
In the sea urchin embryo, primary mesenchyme cells (PMCs) adhere to one another and fuse via filopodia, forming cable-like structures within which skeletal rods are deposited. Although this process was first described more than a century ago, molecules that participate in PMC adhesion and fusion have not been identified. Here we show that KirrelL, a PMC-specific, Ig domain-containing transmembrane protein, is essential for PMC fusion, probably by mediating filopodial adhesions that are a pre-requisite for subsequent membrane fusion. We show that KirrelL is not required for PMC specification, migration, or for direct filopodial contacts between PMCs. In the absence of KirrelL, however, filopodial contacts do not result in fusion. kirrelL is a member of a family of closely related, intronless genes that likely arose through an echinoid-specific gene expansion, possibly via retrotransposition. Our findings are significant in that they establish a direct linkage between the transcriptional network deployed in the PMC lineage and an effector molecule required for a critically important PMC morphogenetic process. In addition, our results point to a conserved role for Ig domain-containing adhesion proteins in facilitating cell fusion in both muscle and non-muscle cell lineages during animal development.

PMID: 27866905 [PubMed - indexed for MEDLINE]

Categories: pubmed

Efficient Synthesis of Glaziovianin A Isoflavone Series from Dill and Parsley Extracts and Their in Vitro/in Vivo Antimitotic Activity.

Tue, 06/06/2017 - 22:01
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Efficient Synthesis of Glaziovianin A Isoflavone Series from Dill and Parsley Extracts and Their in Vitro/in Vivo Antimitotic Activity.

J Nat Prod. 2016 May 27;79(5):1429-38

Authors: Semenov VV, Tsyganov DV, Semenova MN, Chuprov-Netochin RN, Raihstat MM, Konyushkin LD, Volynchuk PB, Marusich EI, Nazarenko VV, Leonov SV, Kiselyov AS

Abstract
A concise six-step protocol for the synthesis of isoflavone glaziovianin A (GVA) and its alkoxyphenyl derivatives 9 starting with readily available plant metabolites from dill and parsley seeds was developed. The reaction sequence involved an efficient conversion of the key intermediate epoxides 7 into the respective β-ketoaldehydes 8 followed by their Cu(I)-mediated cyclization into the target series 9. The biological activity of GVA and its derivatives was evaluated using a panel of seven human cancer cell lines and an in vivo sea urchin embryo assay. Both screening platforms confirmed the antimitotic effect of the parent GVA (9cg) and its alkoxy derivatives. Structure-activity relationship studies suggested that compounds 9cd and 9cf substituted with trimethoxy- and dillapiol-derived B-rings, respectively, were less active than the parent 9cg. Of the evaluated human cancer cell lines, the A375 melanoma cell line was the most sensitive to the tested molecules. Notably, the target compounds were not cytotoxic against human peripheral blood mononuclear cells up to 10 μM concentration. Phenotypic readouts from the sea urchin assay unequivocally suggest a direct microtubule-destabilizing effect of isoflavones 9cg, 9cd, and 9cf.

PMID: 27100701 [PubMed - indexed for MEDLINE]

Categories: pubmed

Maintenance of somatic tissue regeneration with age in short- and long-lived species of sea urchins.

Tue, 06/06/2017 - 22:01
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Maintenance of somatic tissue regeneration with age in short- and long-lived species of sea urchins.

Aging Cell. 2016 Aug;15(4):778-87

Authors: Bodnar AG, Coffman JA

Abstract
Aging in many animals is characterized by a failure to maintain tissue homeostasis and the loss of regenerative capacity. In this study, the ability to maintain tissue homeostasis and regenerative potential was investigated in sea urchins, a novel model to study longevity and negligible senescence. Sea urchins grow indeterminately, regenerate damaged appendages and reproduce throughout their lifespan and yet different species are reported to have very different life expectancies (ranging from 4 to more than 100 years). Quantitative analyses of cell proliferation and apoptosis indicated a low level of cell turnover in tissues of young and old sea urchins of species with different lifespans (Lytechinus variegatus, Strongylocentrotus purpuratus and Mesocentrotus franciscanus). The ability to regenerate damaged tissue was maintained with age as assessed by the regrowth of amputated spines and tube feet (motor and sensory appendages). Expression of genes involved in cell proliferation (pcna), telomere maintenance (tert) and multipotency (seawi and vasa) was maintained with age in somatic tissues. Immunolocalization of the Vasa protein to areas of the tube feet, spines, radial nerve, esophagus and a sub-population of circulating coelomocytes suggests the presence of multipotent cells that may play a role in normal tissue homeostasis and the regenerative potential of external appendages. The results indicate that regenerative potential was maintained with age regardless of lifespan, contrary to the expectation that shorter lived species would invest less in maintenance and repair.

PMID: 27095483 [PubMed - indexed for MEDLINE]

Categories: pubmed

Single embryo-resolution quantitative analysis of reporters permits multiplex spatial cis-regulatory analysis.

Thu, 06/01/2017 - 21:53
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Single embryo-resolution quantitative analysis of reporters permits multiplex spatial cis-regulatory analysis.

Dev Biol. 2017 Feb 15;422(2):92-104

Authors: Guay CL, McQuade ST, Nam J

Abstract
Cis-regulatory modules (CRMs) control spatiotemporal gene expression patterns in embryos. While measurement of quantitative CRM activities has become efficient, measurement of spatial CRM activities still relies on slow, one-by-one methods. To overcome this bottleneck, we have developed a high-throughput method that can simultaneously measure quantitative and spatial CRM activities. The new method builds profiles of quantitative CRM activities measured at single-embryo resolution in many mosaic embryos and uses these profiles as a 'fingerprint' of spatial patterns. We show in sea urchin embryos that the new method, Multiplex and Mosaic Observation of Spatial Information encoded in Cis-regulatory modules (MMOSAIC), can efficiently predict spatial activities of new CRMs and can detect spatial responses of CRMs to gene perturbations. We anticipate that MMOSAIC will facilitate systems-wide functional analyses of CRMs in embryos.

PMID: 28099870 [PubMed - indexed for MEDLINE]

Categories: pubmed

Individual female differences in chemoattractant production change the scale of sea urchin gamete interactions.

Thu, 06/01/2017 - 21:53
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Individual female differences in chemoattractant production change the scale of sea urchin gamete interactions.

Dev Biol. 2017 Feb 15;422(2):186-197

Authors: Hussain YH, Sadilek M, Salad S, Zimmer RK, Riffell JA

Abstract
Sperm selection by females is an important process influencing fertilization and, particularly in broadcast-spawning organisms, often occurs before sperm reach the egg. Waterborne sperm chemoattractants are one mechanism by which eggs selectively influence conspecific sperm behavior, but it remains an open question whether the eggs from different females produce different amounts of sperm chemoattractant, and how that might influence sperm behavior. Here, we quantify the differences in attractant production between females of the sea urchin species Lytechinus pictus and use computational models and microfluidic sperm chemotaxis assays to determine how differences in chemoattractant production between females affects their ability to attract sperm. Our study demonstrates that there is significant individual female variation in egg chemoattractant production, and that this variation changes the scope and strength of sperm attraction. These results provide evidence for the importance of individual female variability in differential sperm attraction and fertilization success.

PMID: 28088316 [PubMed - indexed for MEDLINE]

Categories: pubmed

Differential Nanos 2 protein stability results in selective germ cell accumulation in the sea urchin.

Thu, 06/01/2017 - 21:53
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Differential Nanos 2 protein stability results in selective germ cell accumulation in the sea urchin.

Dev Biol. 2016 Oct 01;418(1):146-56

Authors: Oulhen N, Wessel GM

Abstract
Nanos is a translational regulator required for the survival and maintenance of primordial germ cells. In the sea urchin, Strongylocentrotus purpuratus (Sp), Nanos 2 mRNA is broadly transcribed but accumulates specifically in the small micromere (sMic) lineage, in part because of the 3'UTR element GNARLE leads to turnover in somatic cells but retention in the sMics. Here we found that the Nanos 2 protein is also selectively stabilized; it is initially translated throughout the embryo but turned over in the future somatic cells and retained only in the sMics, the future germ line in this animal. This differential stability of Nanos protein is dependent on the open reading frame (ORF), and is independent of the sumoylation and ubiquitylation pathways. Manipulation of the ORF indicates that 68 amino acids in the N terminus of the Nanos protein are essential for its stability in the sMics whereas a 45 amino acid element adjacent to the zinc fingers targets its degradation. Further, this regulation of Nanos protein is cell autonomous, following formation of the germ line. These results are paradigmatic for the unique presence of Nanos in the germ line by a combination of selective RNA retention, distinctive translational control mechanisms (Oulhen et al., 2013), and now also by defined Nanos protein stability.

PMID: 27424271 [PubMed - indexed for MEDLINE]

Categories: pubmed

A Proteoglycan-Like Molecule Offers Insights Into Ground Substance Changes During Holothurian Intestinal Regeneration.

Wed, 05/31/2017 - 21:50
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A Proteoglycan-Like Molecule Offers Insights Into Ground Substance Changes During Holothurian Intestinal Regeneration.

J Histochem Cytochem. 2016 Jun;64(6):381-93

Authors: Vázquez-Vélez GE, Rodríguez-Molina JF, Quiñones-Frías MC, Pagán M, García-Arrarás JE

Abstract
Extracellular matrix remodeling is an essential component of regenerative processes in metazoans. Among these animals, holothurians (sea cucumbers) are distinguished by their great regenerative capacities. We have previously shown that fibrous collagen as well as other fibrous components disappear from the connective tissue (CT) early during intestinal regeneration, and later return as the organ primordia form. We now report on changes of the nonfibrous component of the CT. We have used Alcian Blue staining and an antibody, Proteoglycan Like-1 (PGL-1), that recognizes a proteoglycan-like antigen to identify the presence of proteoglycans in normal and regenerating intestines. Our results show that early in regeneration, the ground substance resembles that of the mesentery, the structure from where the new intestine originates. As regeneration proceeds, Alcian Blue staining and PGL-1 labeling reorganize, so that by 4 weeks the normal intestinal CT pattern is achieved. Together with our previous findings, the data suggest that CT components that might be detrimental to regeneration disappear early on, while those that might be beneficial to regeneration, such as proteoglycans, are present throughout the regenerative process.

PMID: 27126824 [PubMed - indexed for MEDLINE]

Categories: pubmed

Wnt, Frizzled, and sFRP gene expression patterns during gastrulation in the starfish Patiria (Asterina) pectinifera.

Fri, 05/26/2017 - 21:35
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Wnt, Frizzled, and sFRP gene expression patterns during gastrulation in the starfish Patiria (Asterina) pectinifera.

Gene Expr Patterns. 2016 May;21(1):19-27

Authors: Kawai N, Kuraishi R, Kaneko H

Abstract
By the initial phase of gastrulation, Wnt pathway regulation mediates endomesoderm specification and establishes the animal-vegetal axis, thereby leading to proper gastrulation in starfish. To provide insight into the ancestral mechanism regulating deuterostome gastrulation, we identified the gene expression patterns of Wnt, Frizzled (Fz), and secreted frizzled-related protein (sFRP) family genes, which play a role in the initial stage of the Wnt pathway, in starfish Patiria (Asterina) pectinifera embryos using whole mount in situ hybridization. We identified ten Wnt, four Fz, and two sFRP paralogues. From the hatching blastula to the late gastrula stage, the majority of the Wnt genes and both Fz5/8 and sFRP1/5 were expressed in the posterior and anterior half of the embryo, respectively. Wnt8, Fz1, and Fz4 showed restricted expression in the lateral ectoderm. On the other hand, several genes were expressed de novo in the restricted domain of the archenteron at the late gastrula stage. These results suggest that the canonical and/or non-canonical Wnt pathway might implicate endomesoderm specification, anterior-posterior axis establishment, anterior-posterior patterning, and archenteron morphogenesis in the developmental context of starfish embryos. From comparison with the expression patterns observed in Patria miniata, we consider that the Wnt pathway is conserved among starfishes.

PMID: 27346542 [PubMed - indexed for MEDLINE]

Categories: pubmed

A conserved alternative form of the purple sea urchin HEB/E2-2/E2A transcription factor mediates a switch in E-protein regulatory state in differentiating immune cells.

Fri, 05/26/2017 - 21:35
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A conserved alternative form of the purple sea urchin HEB/E2-2/E2A transcription factor mediates a switch in E-protein regulatory state in differentiating immune cells.

Dev Biol. 2016 Aug 01;416(1):149-61

Authors: Schrankel CS, Solek CM, Buckley KM, Anderson MK, Rast JP

Abstract
E-proteins are basic helix-loop-helix (bHLH) transcription factors with essential roles in animal development. In mammals, these are encoded by three loci: E2-2 (ITF-2/ME2/SEF2/TCF4), E2A (TCF3), and HEB (ME1/REB/TCF12). The HEB and E2-2 paralogs are expressed as alternative (Alt) isoforms with distinct N-terminal sequences encoded by unique exons under separate regulatory control. Expression of these alternative transcripts is restricted relative to the longer (Can) forms, suggesting distinct regulatory roles, although the functions of the Alt proteins remain poorly understood. Here, we characterize the single sea urchin E-protein ortholog (SpE-protein). The organization of the SpE-protein gene closely resembles that of the extended HEB/E2-2 vertebrate loci, including a transcript that initiates at a homologous alternative transcription start site (SpE-Alt). The existence of an Alt form in the sea urchin indicates that this feature predates the emergence of the vertebrates. We present additional evidence indicating that this transcript was present in the common bilaterian ancestor. In contrast to the widely expressed canonical form (SpE-Can), SpE-Alt expression is tightly restricted. SpE-Alt is expressed in two phases: first in aboral non-skeletogenic mesenchyme (NSM) cells and then in oral NSM cells preceding their differentiation and ingression into the blastocoel. Derivatives of these cells mediate immune response in the larval stage. Inhibition of SpE-Alt activity interferes with these events. Notably, although the two isoforms are initially co-expressed, as these cells differentiate, SpE-Can is excluded from the SpE-Alt(+) cell population. This mutually exclusive expression is dependent on SpE-Alt function, which reveals a previously undescribed negative regulatory linkage between the two E-protein forms. Collectively, these findings reorient our understanding of the evolution of this transcription factor family and highlight fundamental properties of E-protein biology.

PMID: 27265865 [PubMed - indexed for MEDLINE]

Categories: pubmed

An Elk transcription factor is required for Runx-dependent survival signaling in the sea urchin embryo.

Fri, 05/26/2017 - 21:35
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An Elk transcription factor is required for Runx-dependent survival signaling in the sea urchin embryo.

Dev Biol. 2016 Aug 01;416(1):173-86

Authors: Rizzo F, Coffman JA, Arnone MI

Abstract
Elk proteins are Ets family transcription factors that regulate cell proliferation, survival, and differentiation in response to ERK (extracellular-signal regulated kinase)-mediated phosphorylation. Here we report the embryonic expression and function of Sp-Elk, the single Elk gene of the sea urchin Strongylocentrotus purpuratus. Sp-Elk is zygotically expressed throughout the embryo beginning at late cleavage stage, with peak expression occurring at blastula stage. Morpholino antisense-mediated knockdown of Sp-Elk causes blastula-stage developmental arrest and embryo disintegration due to apoptosis, a phenotype that is rescued by wild-type Elk mRNA. Development is also rescued by Elk mRNA encoding a serine to aspartic acid substitution (S402D) that mimics ERK-mediated phosphorylation of a conserved site that enhances DNA binding, but not by Elk mRNA encoding an alanine substitution at the same site (S402A). This demonstrates both that the apoptotic phenotype of the morphants is specifically caused by Elk depletion, and that phosphorylation of serine 402 of Sp-Elk is critical for its anti-apoptotic function. Knockdown of Sp-Elk results in under-expression of several regulatory genes involved in cell fate specification, cell cycle control, and survival signaling, including the transcriptional regulator Sp-Runt-1 and its target Sp-PKC1, both of which were shown previously to be required for cell survival during embryogenesis. Both Sp-Runt-1 and Sp-PKC1 have sequences upstream of their transcription start sites that specifically bind Sp-Elk. These results indicate that Sp-Elk is the signal-dependent activator of a feed-forward gene regulatory circuit, consisting also of Sp-Runt-1 and Sp-PKC1, which actively suppresses apoptosis in the early embryo.

PMID: 27235147 [PubMed - indexed for MEDLINE]

Categories: pubmed

Heavy rare earth elements affect early life stages in Paracentrotus lividus and Arbacia lixula sea urchins.

Wed, 05/10/2017 - 21:00
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Heavy rare earth elements affect early life stages in Paracentrotus lividus and Arbacia lixula sea urchins.

Environ Res. 2017 Apr;154:240-246

Authors: Oral R, Pagano G, Siciliano A, Gravina M, Palumbo A, Castellano I, Migliaccio O, Thomas PJ, Guida M, Tommasi F, Trifuoggi M

Abstract
BACKGROUND: Heavy rare earth elements (HREEs) have been scarcely studied for their toxicity, in spite of their applications in several technologies. Thus HREEs require timely investigations for their adverse health effects.
METHODS: Paracentrotus lividus and Arbacia lixula embryos and sperm were exposed to trichloride salts of five HREEs (Dy, Ho, Er, Yb and Lu) and to Ce(III) as a light REE (LREE) reference to evaluate: 1) developmental defects (% DD) in HREE-exposed larvae or in the offspring of HREE-exposed sperm; 2) mitotic anomalies; 3) fertilization success; and 4) reactive oxygen species (ROS) formation, and nitric oxide (NO) and malondialdehyde (MDA) levels. Nominal HREE concentrations were confirmed by inductively coupled plasma mass spectrometry (ICP-MS).
RESULTS: HREEs induced concentration-related DD increases in P. lividus and A. lixula larvae, ranging from no significant DD increase at 10(-7)M HREEs up to ≅100% DD at 10(-5)M HREE. Larvae exposed to 10(-5)M Ce(III) resulted in less severe DD rates compared to HREEs. Decreased mitotic activity and increased aberration rates were found in HREE-exposed P. lividus embryos. Significant increases in ROS formation and NO levels were found both in HREE-exposed and in Ce(III) embryos, whereas only Ce(III), but not HREEs resulted in significant increase in MDA levels. Sperm exposure to HREEs (10(-5)-10(-4)M) resulted in a concentration-related decrease in fertilization success along with increase in offspring damage. These effects were significantly enhanced for Dy(III), Ho(III), Er(III) and Yb(III), compared to Lu(III) and to Ce(III).
CONCLUSION: HREE-associated toxicity affected embryogenesis, fertilization, cytogenetic and redox endpoints showing different toxicities of tested HREEs.

PMID: 28107742 [PubMed - indexed for MEDLINE]

Categories: pubmed

A Model Sea Urchin Spicule Matrix Protein Self-Associates To Form Mineral-Modifying Protein Hydrogels.

Wed, 05/10/2017 - 21:00
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A Model Sea Urchin Spicule Matrix Protein Self-Associates To Form Mineral-Modifying Protein Hydrogels.

Biochemistry. 2016 Aug 09;55(31):4410-21

Authors: Jain G, Pendola M, Rao A, Cölfen H, 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 the SpSM30A-F isoforms. However, because of limited abundance, it has been difficult to pursue extensive biochemical studies of the SpSM30 proteins and deduce their role in spicule formation and mineralization. To circumvent these problems, we expressed a model recombinant spicule matrix protein, rSpSM30B/C, which possesses the key sequence attributes of isoforms "B" and "C". Our findings indicate that rSpSM30B/C is expressed in insect cells as a single polypeptide containing variations in glycosylation that create microheterogeneity in rSpSM30B/C molecular masses. These post-translational modifications incorporate O- and N-glycans and anionic mono- and bisialylated and mono- and bisulfated monosaccharides on the protein molecules and enhance its aggregation propensity. Bioinformatics and biophysical experiments confirm that rSpSM30B/C is an intrinsically disordered, aggregation-prone protein that forms porous protein hydrogels that control the in vitro mineralization process in three ways: (1) increase the time interval for prenucleation cluster formation and transiently stabilize an ACC polymorph, (2) promote and organize single-crystal calcite nanoparticles, and (3) promote faceted growth and create surface texturing of calcite crystals. These features are also common to mollusk shell nacre proteins, and we conclude that rSpSM30B/C is a spiculogenesis protein that exhibits traits found in other calcium carbonate mineral modification proteins.

PMID: 27426695 [PubMed - indexed for MEDLINE]

Categories: pubmed

Transcriptomic responses to seawater acidification among sea urchin populations inhabiting a natural pH mosaic.

Thu, 05/04/2017 - 20:52
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Transcriptomic responses to seawater acidification among sea urchin populations inhabiting a natural pH mosaic.

Mol Ecol. 2017 Apr;26(8):2257-2275

Authors: Evans TG, Pespeni MH, Hofmann GE, Palumbi SR, Sanford E

Abstract
Increasing awareness of spatial and temporal variation in ocean pH suggests some marine populations may be adapted to local pH regimes and will therefore respond differently to present-day pH variation and to long-term ocean acidification. In the Northeast Pacific Ocean, differences in the strength of coastal upwelling cause latitudinal variation in prevailing pH regimes that are hypothesized to promote local adaptation and unequal pH tolerance among resident populations. In this study, responses to experimental seawater acidification were compared among embryos and larvae from six populations of purple sea urchins (Strongylocentrotus purpuratus) inhabiting areas that differ in their frequency of low pH exposure and that prior research suggests are locally adapted to seawater pH. Transcriptomic analyses demonstrate urchin populations most frequently exposed to low pH seawater responded to experimental acidification by expressing genes within major ATP-producing pathways at greater levels than populations encountering low pH less often. Multiple genes within the tricarboxylic acid cycle, electron transport chain and fatty acid beta oxidation pathways were upregulated in urchin populations experiencing low pH conditions most frequently. These same metabolic pathways were significantly over-represented among genes both expressed in a population-specific manner and putatively under selection to enhance low pH tolerance. Collectively, these data suggest natural selection is acting on metabolic gene networks to redirect ATP toward maintaining acid-base homeostasis and enhance tolerance of seawater acidification. As a trade-off, marine populations more tolerant of low pH may have less energy to put towards other aspects of fitness and to respond to additional ocean change.

PMID: 28141889 [PubMed - indexed for MEDLINE]

Categories: pubmed

Genomic Characterization of the Evolutionary Potential of the Sea Urchin Strongylocentrotus droebachiensis Facing Ocean Acidification.

Thu, 05/04/2017 - 20:52
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Genomic Characterization of the Evolutionary Potential of the Sea Urchin Strongylocentrotus droebachiensis Facing Ocean Acidification.

Genome Biol Evol. 2016 Dec 01;8(12):3672-3684

Authors: Runcie DE, Dorey N, Garfield DA, Stumpp M, Dupont S, Wray GA

Abstract
Ocean acidification (OA) is increasing due to anthropogenic CO2 emissions and poses a threat to marine species and communities worldwide. To better project the effects of acidification on organisms' health and persistence, an understanding is needed of the 1) mechanisms underlying developmental and physiological tolerance and 2) potential populations have for rapid evolutionary adaptation. This is especially challenging in nonmodel species where targeted assays of metabolism and stress physiology may not be available or economical for large-scale assessments of genetic constraints. We used mRNA sequencing and a quantitative genetics breeding design to study mechanisms underlying genetic variability and tolerance to decreased seawater pH (-0.4 pH units) in larvae of the sea urchin Strongylocentrotus droebachiensis. We used a gene ontology-based approach to integrate expression profiles into indirect measures of cellular and biochemical traits underlying variation in larval performance (i.e., growth rates). Molecular responses to OA were complex, involving changes to several functions such as growth rates, cell division, metabolism, and immune activities. Surprisingly, the magnitude of pH effects on molecular traits tended to be small relative to variation attributable to segregating functional genetic variation in this species. We discuss how the application of transcriptomics and quantitative genetics approaches across diverse species can enrich our understanding of the biological impacts of climate change.

PMID: 28082601 [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.

Tue, 05/02/2017 - 20:44
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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