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1.
Sci Rep ; 10(1): 8184, 2020 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-32424321

RESUMO

The corallivorous Crown-of-Thorns Starfish (CoTS, Acanthaster spp.) has been linked with the widespread loss of scleractinian coral cover on Indo-Pacific reefs during periodic population outbreaks. Here, we re-examine CoTS consumption by coral reef fish species by using new DNA technologies to detect Pacific Crown-of-Thorns Starfish (Acanthaster cf. solaris) in fish faecal and gut content samples. CoTS DNA was detected in samples from 18 different coral reef fish species collected on reefs at various stages of CoTS outbreaks in the Great Barrier Reef Marine Park, nine of which had not been previously reported to feed on CoTS. A comprehensive set of negative and positive control samples confirmed that our collection, processing and analysis procedures were robust, although food web transfer of CoTS DNA cannot be ruled out for some fish species. Our results, combined with the (i) presence of CoTS spines in some samples, (ii) reported predation on CoTS gametes, larvae and settled individuals, and (iii) known diet information for fish species examined, strongly indicate that direct fish predation on CoTS may well be more common than is currently appreciated. We provide recommendations for specific management approaches to enhance predation on CoTS by coral reef fishes, and to support the mitigation of CoTS outbreaks and reverse declines in hard coral cover.


Assuntos
Código de Barras de DNA Taxonômico , Fezes , Intestinos , Estrelas-do-Mar/classificação , Estrelas-do-Mar/genética , Animais , Recifes de Corais , Comportamento Predatório
2.
PLoS One ; 15(1): e0227223, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31910238

RESUMO

Several starfish (Echinodermata, Asteroidea) are keystone species of marine ecosystems, but some of the species are difficult to identify using morphological criteria only. The common sunstar, Crossaster papposus (Linnaeus, 1767), is a conspicuous species with a wide circumboreal distribution. In 1900, a closely similar species, C. squamatus (Döderlein, 1900) was described from the NE Atlantic Ocean, but subsequent authors have differed in their views on whether this is a valid taxon or rather an ecotype associated with temperature variations. We assessed the differentiating morphological characters of specimens from Norwegian and Greenland waters identified as C. papposus and C. squamatus and compared their distributions in the NE Atlantic as inferred from research cruises. The field data show that C. papposus is found mainly in temperate and shallow waters, whereas C. squamatus resides on the shelf-break in colder, mixed water masses. Intraspecific diversity and interspecific genetic differentiation of the two putative species, and their phylogenetic relationships to several Crossaster congeners worldwide, were explored using mitochondrial and nuclear DNA sequences. The molecular evidence suggests that C. papposus is the more diverse and geographically structured taxon, in line with its wide distribution. C. papposus and C. squamatus are closely related, yet clearly distinct taxa, while C. papposus and C. multispinus H.L. Clark, 1916, the latter from the South Pacific Ocean, are closely related, possibly sister taxa.


Assuntos
Distribuição Animal , Estrelas-do-Mar/genética , Animais , Oceano Atlântico , Núcleo Celular/genética , DNA Mitocondrial/genética , DNA Mitocondrial/isolamento & purificação , Groenlândia , Noruega , Oceano Pacífico , Filogenia , Análise de Sequência de DNA , Estrelas-do-Mar/classificação , Temperatura
3.
Sci Rep ; 9(1): 16201, 2019 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-31700051

RESUMO

Understanding how changes in developmental gene expression alter morphogenesis is a fundamental problem in development and evolution. A promising approach to address this problem is to compare the developmental transcriptomes between related species. The echinoderm phylum consists of several model species that have significantly contributed to the understanding of gene regulation and evolution. Particularly, the regulatory networks of the sea star, Patiria miniata (P. miniata), have been extensively studied, however developmental transcriptomes for this species were lacking. Here we generated developmental transcriptomes of P. miniata and compared these with those of two sea urchins species. We demonstrate that the conservation of gene expression depends on gene function, cell type and evolutionary distance. With increasing evolutionary distance the interspecies correlations in gene expression decreases. The reduction is more severe in the correlations between morphologically equivalent stages (diagonal elements) than in the correlation between morphologically distinct stages (off-diagonal elements). This could reflect a decrease in the morphological constraints compared to other constraints that shape gene expression at large evolutionary divergence. Within this trend, the interspecies correlations of developmental control genes maintain their diagonality at large evolutionary distance, and peak at the onset of gastrulation, supporting the hourglass model of phylotypic stage conservation.


Assuntos
Evolução Molecular , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Estrelas-do-Mar/crescimento & desenvolvimento , Estrelas-do-Mar/genética , Animais , Homologia de Sequência do Ácido Nucleico , Estrelas-do-Mar/embriologia
4.
Philos Trans R Soc Lond B Biol Sci ; 374(1784): 20190195, 2019 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-31495313

RESUMO

Sea stars use adhesive secretions to attach their numerous tube feet strongly and temporarily to diverse surfaces. After detachment of the tube feet, the adhesive material stays bound to the substrate as so-called 'footprints'. In the common sea star species Asterias rubens, the adhesive material has been studied extensively and the first sea star footprint protein (Sfp1) has been characterized. We identified Sfp1-like sequences in 17 additional sea star species, representing different taxa and tube foot morphologies, and analysed the evolutionary conservation of this protein. In A. rubens, we confirmed the expression of 34 footprint proteins in the tube foot adhesive epidermis, with 22 being exclusively expressed in secretory cells of the adhesive epidermis and 12 showing an additional expression in the stem epidermis. The sequences were used for BLAST searches in seven asteroid transcriptomes providing a first insight in the conservation of footprint proteins among sea stars. Our results highlighted a high conservation of the large proteins making up the structural core of the footprints, whereas smaller, potential surface-binding proteins might be more variable among sea star species. This article is part of the theme issue 'Transdisciplinary approaches to the study of adhesion and adhesives in biological systems'.


Assuntos
Estrelas-do-Mar/fisiologia , Transcriptoma , Animais , Proteínas/genética , Proteínas/fisiologia , Especificidade da Espécie , Estrelas-do-Mar/genética
5.
Cell Tissue Res ; 377(3): 445-458, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31446445

RESUMO

The emergence of a specialized system for food digestion and nutrient absorption was a crucial innovation for multicellular organisms. Digestive systems with different levels of complexity evolved in different animals, with the endoderm-derived one-way gut of most bilaterians to be the prevailing and more specialized form. While the molecular events regulating the early phases of embryonic tissue specification have been deeply investigated in animals occupying different phylogenetic positions, the mechanisms underlying gut patterning and gut-associated structures differentiation are still mostly obscure. In this review, we describe the main discoveries in gut and gut-associated structures development in echinoderm larvae (mainly for sea urchin and, when available, for sea star) and compare them with existing information in vertebrates. An impressive degree of conservation emerges when comparing the transcription factor toolkits recruited for gut cells and tissue differentiation in animals as diverse as echinoderms and vertebrates, thus suggesting that their function emerged in the deuterostome ancestor.


Assuntos
Trato Gastrointestinal , Ouriços-do-Mar/fisiologia , Estrelas-do-Mar/fisiologia , Vertebrados/fisiologia , Animais , Evolução Biológica , Trato Gastrointestinal/citologia , Trato Gastrointestinal/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Redes Reguladoras de Genes , Larva/fisiologia , Ouriços-do-Mar/genética , Estrelas-do-Mar/genética , Vertebrados/genética
6.
Biol Bull ; 236(3): 174-185, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31167087

RESUMO

Two juvenile specimens of a new species of Oreaster were collected at Parque Nacional Arrecife Alacranes and Triángulos Oeste in the southern Gulf of Mexico. DNA of mitochondrial loci identifies them as members of the same clade as cloning larvae of Oreaster found abundantly in waters of the Florida Current-Gulf Stream system, and distinct from Oreaster clavatus and Oreaster reticulatus, the two known Oreasteridae species in the North Atlantic. Larvae from the new species of Oreaster persist as clones but also metamorphose and settle to the benthos with typical asteroid morphology.


Assuntos
Estrelas-do-Mar/classificação , Estrelas-do-Mar/crescimento & desenvolvimento , Animais , Golfo do México , Larva/classificação , Larva/crescimento & desenvolvimento , Metamorfose Biológica , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Especificidade da Espécie , Estrelas-do-Mar/genética
7.
Gen Comp Endocrinol ; 281: 41-48, 2019 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-31102581

RESUMO

The Acanthaster planci species-complex [Crown-of-Thorns Seastar (COTS)] are highly fecund echinoderms that exhibit population outbreaks on coral reef ecosystems worldwide, including the Australian Great Barrier Reef. A better understanding of the COTS molecular biology is critical towards efforts in controlling outbreaks and assisting reef recovery. In seastars, the heterodimeric relaxin-like gonad stimulating peptide (RGP) is responsible for triggering a neuroendocrine cascade that regulates resumption of oocyte meiosis prior to spawning. Our comparative RNA-seq analysis indicates a general increase in RGP gene expression in the female radial nerve cord during the reproductive season. Also, the sensory tentacles demonstrate a significantly higher expression level than radial nerve cord. A recombinant COTS RGP, generated in a yeast expression system, is highly effective in inducing oocyte germinal vesicle breakdown (GVBD), followed by ovulation from ovarian fragments. The findings of this study provide a foundation for more in-depth molecular analysis of the reproductive neuroendocrine physiology of the COTS and the RGP.


Assuntos
Oócitos/metabolismo , Ovário/metabolismo , Ovulação/fisiologia , Proteínas Recombinantes/farmacologia , Relaxina/farmacologia , Estrelas-do-Mar/fisiologia , Animais , Bioensaio , Feminino , Oócitos/efeitos dos fármacos , Ovário/efeitos dos fármacos , Ovulação/efeitos dos fármacos , Relaxina/genética , Relaxina/metabolismo , Estrelas-do-Mar/efeitos dos fármacos , Estrelas-do-Mar/genética
8.
Heredity (Edinb) ; 123(5): 622-633, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31073238

RESUMO

Poecilogony, or multiple developmental modes in a single species, is exceedingly rare. Several species described as poecilogenous were later demonstrated to be multiple (cryptic) species with a different developmental mode. The Southern Ocean is known to harbor a high proportion of brooders (Thorson's Rule) but with an increasing number of counter examples over recent years. Here we evaluated poecilogony vs. crypticism in the brittle star Astrotoma agassizii across the Southern Ocean. This species was initially described from South America as a brooder before some pelagic stages were identified in Antarctica. Reproductive and mitochondrial data were combined to unravel geographic and genetic variation of developmental modes. Our results indicate that A. agassizii is composed of seven well-supported and deeply divergent clades (I: Antarctica and South Georgia; II: South Georgia and Sub-Antarctic locations including Kerguelen, Patagonian shelf, and New Zealand; III-VI-VII: Patagonian shelf, IV-V: South Georgia). Two of these clades demonstrated strong size dimorphism when in sympatry and can be linked to differing developmental modes (Clade V: dwarf brooder vs. Clade I: giant broadcaster). Based on their restricted geographic distributions and on previous studies, it is likely that Clades III-VI-VII are brooders. Clade II is composed of different morphological species, A. agassizii and A. drachi, the latter originally used as the outgroup. By integrating morphology, reproductive, and molecular data we conclude that the variation identified in A. agassizii is best described as crypticism rather than poecilogony.


Assuntos
DNA Mitocondrial/genética , Evolução Molecular , Filogenia , Estrelas-do-Mar/genética , Animais , Regiões Antárticas , América do Sul
9.
Proc Biol Sci ; 286(1901): 20182701, 2019 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-31014214

RESUMO

Arm loss through a separation at a specialized autotomy plane in echinoderms is inextricably linked to regeneration, but the link between these phenomena is poorly explored. We investigated nervous system regeneration post-autotomy in the asteriid seastar Coscinasterias muricata, focusing on the reorganization of the radial nerve cord (RNC) into the ectoneural neuroepithelium and neuropile, and the hyponeural region, using antibodies to the seastar-specific neuropeptide SALMFamide-1 (S1). Parallel changes in the associated haemal and coelomic vessels were also examined. A new arm bud appeared in 3-5 days with regeneration over three weeks. At the nerve stump and in the RNC immediately behind, the haemal sinus/hyponeural coelomic compartments enlarged into a hypertrophied space filled with migratory cells that appear to be involved in wound healing and regeneration. The haemal and coelomic compartments provided a conduit for these cells to gain rapid access to the regeneration site. An increase in the number of glia-like cells indicates the importance of these cells in regeneration. Proximal to the autotomy plane, the original RNC exhibited Wallerian-type degeneration, as seen in disorganized axons and enlarged S1-positive varicosities. The imperative to regrow lost arms quickly is reflected in the efficiency of regeneration from the autotomy plane facilitated by the rapid appearance of progenitor-like migratory cells. In parallel to its specialization for defensive arm detachment, the autotomy plane appears to be adapted to promote regeneration. This highlights the importance of examining autotomy-induced regeneration in seastars as a model system to study nervous system regeneration in deuterostomes and the mechanisms involved with the massive migration of stem-like cells to facilitate rapid recovery.


Assuntos
Expressão Gênica/fisiologia , Neuropeptídeos/genética , Regeneração/genética , Estrelas-do-Mar/fisiologia , Animais , Neuropeptídeos/metabolismo , Estrelas-do-Mar/genética
10.
Methods Cell Biol ; 150: 189-222, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30777176

RESUMO

We describe methods and techniques for introduction of molecular probes in the form of synthetic mRNA by rapid repetitive microinjection into oocytes or early embryos of echinoderms and various invertebrates. Construct assembly is followed by standard kit-based in vitro mRNA synthesis, with slight modifications to optimize expression and clean-up. Variations of a basic microinjection procedures are detailed for echinoderms: starfish oocytes (Patiria miniata or other species), purple urchin (Strongylocentrotus purpuratus) and sand dollar (Dendraster excentricus) zygotes, with notes included for other invertebrate eggs and embryos as well.


Assuntos
Embrião não Mamífero/citologia , Embrião não Mamífero/fisiologia , Microinjeções/métodos , Sondas Moleculares/administração & dosagem , Oócitos/citologia , RNA Mensageiro/administração & dosagem , Animais , Ouriços-do-Mar/genética , Estrelas-do-Mar/genética
11.
Methods Cell Biol ; 150: 471-483, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30777190

RESUMO

The explosion in the amount of genomic data has changed how we educate future biologists. Students are inundated with information and need to develop skills in how to observe and understand this data. This chapter describes a teaching laboratory for undergraduate Genetics students that uses a combination of bioinformatics and wet lab exercises to teach skills in applying genomic data to a real scientific question. Students identify a target protein and search for the encoding RNA in newly available sea star transcriptome databases. The students design primers against specific regions or domains in their target RNA and amplify these by reverse transcription PCR. The PCR reactions are analyzed by agarose gel electrophoresis. The goal of this laboratory is to provide an example of how bioinformatics can be used to solve a real biological problem.


Assuntos
Expressão Gênica/genética , Estrelas-do-Mar/genética , Animais , Biologia Computacional/métodos , Bases de Dados Genéticas , Genômica/métodos , RNA/genética , Estudantes , Transcriptoma/genética
12.
BMC Genomics ; 19(1): 853, 2018 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-30497381

RESUMO

BACKGROUND: Chemosensation is a critical signalling process for all organisms and is achieved through the interaction between chemosensory receptors and their ligands. The Crown-of-thorns starfish, Acanthaster planci species complex (COTS), is a predator of coral polyps and Acanthaster cf. solaris is currently considered to be one of the main drivers of coral loss on the Great Barrier Reef in Queensland, Australia. RESULTS: This study reveals the presence of putative variant Ionotropic Receptors (IRs) which are differentially expressed in the olfactory organs of COTS. Several other types of G protein-coupled receptors such as adrenergic, metabotropic glutamate, cholecystokinin, trace-amine associated, GRL101 and GPCR52 receptors have also been identified. Several receptors display male-biased expression within the sensory tentacles, indicating possible reproductive significance. CONCLUSIONS: Many of the receptors identified in this study may have a role in reproduction and are therefore key targets for further investigation. Based on their differential expression within the olfactory organs and presence in multiple tissues, it is possible that several of these receptor types have expanded within the Echinoderm lineage. Many are likely to be species-specific with novel ligand-binding affinity and a diverse range of functions. This study is the first to describe the presence of variant Ionotropic Glutamate Receptors in any Echinoderm, and is only the second study to investigate chemosensory receptors in any starfish or marine pest. These results represent a significant step forward in understanding the chemosensory abilities of COTS.


Assuntos
Perfilação da Expressão Gênica , Proteínas de Insetos/genética , Receptores de Superfície Celular/genética , Órgãos dos Sentidos/metabolismo , Estrelas-do-Mar/genética , Animais , Feminino , Proteínas de Insetos/metabolismo , Funções Verossimilhança , Masculino , Filogenia , Receptores de Superfície Celular/metabolismo
13.
BMC Evol Biol ; 18(1): 168, 2018 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-30419810

RESUMO

BACKGROUND: Opsins are G protein-coupled receptors used for both visual and non-visual photoreception, and these proteins evolutionarily date back to the base of the bilaterians. In the current sequencing age, phylogenomic analysis has proven to be a powerful tool, facilitating the increase in knowledge about diversity within the opsin subclasses and, so far, at least nine types of opsins have been identified. Within echinoderms, opsins have been studied in Echinoidea and Ophiuroidea, which do not possess proper image forming eyes, but rather widely dispersed dermal photoreceptors. However, most species of Asteroidea, the starfish, possess true eyes and studying them will shed light on the diversity of opsin usage within echinoderms and help resolve the evolutionary history of opsins. RESULTS: Using high-throughput RNA sequencing, we have sequenced and analyzed the transcriptomes of different Acanthaster planci tissue samples: eyes, radial nerve, tube feet and a mixture of tissues from other organs. At least ten opsins were identified, and eight of them were found significantly differentially expressed in both eyes and radial nerve, with R-opsin being the most highly expressed in the eye. CONCLUSION: This study provides new important insight into the involvement of opsins in visual and nonvisual photoreception. Of relevance, we found the first indication of an r-opsin photopigment expressed in a well-developed visual eye in a deuterostome animal. Additionally, we provided tissue specific A. planci transcriptomes that will aid in future Evo Devo studies.


Assuntos
Olho/metabolismo , Opsinas/metabolismo , Estrelas-do-Mar/metabolismo , Motivos de Aminoácidos , Animais , Sequência de Bases , Teorema de Bayes , Evolução Biológica , Cílios/metabolismo , Regulação da Expressão Gênica , Opsinas/genética , Filogenia , Estrelas-do-Mar/genética
14.
Biochem Biophys Res Commun ; 506(2): 361-371, 2018 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-30297103

RESUMO

Starfish and sea urchin are excellent models to study the mechanisms that regulate oocyte maturation and egg activation. Hormonal stimulation of starfish oocytes and their following interaction with spermatozoa induce rapid changes of F-actin and Ca2+ increases which are prerequisites for normal fertilization and development. Fully grown oocytes isolated from the gonads of starfish contain a large nucleus (∼60-70 µm) (termed germinal vesicle, GV), which is arrested at the first prophase of meiosis. If inseminated, these immature oocytes are penetrated by additional spermatozoa. However, starfish oocytes naturally shed into the sea have already initiated the (meiotic) maturation and are normally fertilized between GV breakdown and the extrusion of the first polar body. This is considered the optimum period to ensure monospermic instead of polyspermic fertilization. By contrast, sea urchin eggs are fertilized only after being fully matured, i.e., at the end of the two meiotic divisions. Here, we provide a comparative review of the role of the actin cytoskeleton in oocyte maturation and fertilization in starfish and sea urchin. It has become increasingly evident that the exquisite regulation of the cortical F-actin is involved in nearly all aspects of the molecular events taking place during the progression of meiotic maturation and fertilization.


Assuntos
Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Cálcio/metabolismo , Oócitos/metabolismo , ATPases Transportadoras de Cálcio da Membrana Plasmática/metabolismo , Ouriços-do-Mar/metabolismo , Estrelas-do-Mar/metabolismo , Citoesqueleto de Actina/genética , Citoesqueleto de Actina/ultraestrutura , Actinas/química , Actinas/genética , Animais , Sinalização do Cálcio , Feminino , Fertilização/genética , Regulação da Expressão Gênica , Cinética , Masculino , Meiose , Oócitos/citologia , ATPases Transportadoras de Cálcio da Membrana Plasmática/genética , Ouriços-do-Mar/citologia , Ouriços-do-Mar/genética , Especificidade da Espécie , Espermatozoides/citologia , Espermatozoides/metabolismo , Estrelas-do-Mar/citologia , Estrelas-do-Mar/genética
15.
Results Probl Cell Differ ; 65: 547-568, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30083935

RESUMO

Acanthaster planci, commonly known as the "crown-of-thorns starfish" (COTS) are famous for decimating coral reefs, yet the unique features of the COTS genome make the starfish a useful system for genomic and evolutionary developmental research. The COTS genome assembly is an order of magnitude more highly contiguous than other recently sequenced echinoderm genome assemblies. The high resolution of the COTS assembly is likely related to low heterozygosity resulting from historical population dynamics and possibly a recent population expansion. The high-resolution genome assembly is biologically meaningful, as confirmed by the discovery of several intact gene clusters. Therefore, the COTS genome is an ideal testing ground for new genomic technologies and bioinformatics tools.


Assuntos
Recifes de Corais , Genoma/genética , Genômica , Estrelas-do-Mar/genética , Estrelas-do-Mar/patogenicidade , Animais
16.
Proc Natl Acad Sci U S A ; 115(27): 7069-7074, 2018 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-29915091

RESUMO

Standing genetic variation enables or restricts a population's capacity to respond to changing conditions, including the extreme disturbances expected to increase in frequency and intensity with continuing anthropogenic climate change. However, we know little about how populations might respond to extreme events with rapid genetic shifts, or how population dynamics may influence and be influenced by population genomic change. We use a range-wide epizootic, sea star wasting disease, that onset in mid-2013 and caused mass mortality in Pisaster ochraceus to explore how a keystone marine species responded to an extreme perturbation. We integrated field surveys with restriction site-associated DNA sequencing data to (i) describe the population dynamics of mortality and recovery, and (ii) compare allele frequencies in mature P. ochraceus before the disease outbreak with allele frequencies in adults and new juveniles after the outbreak, to identify whether selection may have occurred. We found P. ochraceus suffered 81% mortality in the study region between 2012 and 2015, and experienced a concurrent 74-fold increase in recruitment beginning in late 2013. Comparison of pre- and postoutbreak adults revealed significant allele frequency changes at three loci, which showed consistent changes across the large majority of locations. Allele frequency shifts in juvenile P. ochraceus (spawned from premortality adults) were consistent with those seen in adult survivors. Such parallel shifts suggest detectable signals of selection and highlight the potential for persistence of this change in subsequent generations, which may influence the resilience of this keystone species to future outbreaks.


Assuntos
Alelos , Frequência do Gene , Estrelas-do-Mar/genética , Síndrome de Emaciação/genética , Síndrome de Emaciação/veterinária , Animais
17.
Dev Comp Immunol ; 86: 203-213, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29733880

RESUMO

Antimicrobial peptides (AMPs) are components of innate immunity found in many forms of life. However, there have been no reports of AMPs in sea star (Phylum Echinodermata). Here we report the isolation and characterization of a novel antimicrobial peptide from the coelomic epithelium extract of the sea star Patiria pectinifera. The isolated peptide comprises 38 amino acid residues, is cationic (pI 9.2), has four cysteine residues that form two disulfide bonds (C1-C3 and C2-C4), is amidated at the C-terminus, and is designated P. pectinifera cysteine-rich antimicrobial peptide (PpCrAMP). Synthetic PpCrAMP identical to the native peptide exhibited the most potent antimicrobial activity compared to analogs with different disulfide bond configurations. Expression analysis of PpCrAMP precursor transcripts revealed constitutive expression in the coelomic epithelium and tube feet of P. pectinifera. Analysis of genomic DNA and cDNA encoding the PpCrAMP precursor protein revealed that an intron splits the coding region of the mature peptide into a positively charged N-terminal domain and a C-terminal domain harboring four cysteine residues and a glycine for C-terminal amidation. No significant homology with other known AMPs was observed, while orthologs of PpCrAMP were found in other echinoderm species. These findings indicate that PpCrAMP is the prototype of a family a novel cysteine-rich AMPs that participate in mechanisms of innate immunity in echinoderms. Furthermore, the discovery of PpCrAMP may lead to the identification of related AMPs in vertebrates and protostome invertebrates.


Assuntos
Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/metabolismo , Estrelas-do-Mar/genética , Estrelas-do-Mar/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular/métodos , Cisteína/genética , Cisteína/metabolismo , DNA Complementar , Imunidade Inata/genética , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Homologia de Sequência de Aminoácidos
18.
Dev Biol ; 433(2): 297-309, 2018 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-29291979

RESUMO

Regeneration is a post-embryonic developmental process that ensures complete morphological and functional restoration of lost body parts. The repair phase is a key step for the effectiveness of the subsequent regenerative process: in vertebrates, efficient re-epithelialisation, rapid inflammatory/immune response and post-injury tissue remodelling are fundamental aspects for the success of this phase, their impairment leading to an inhibition or total prevention of regeneration. Among deuterostomes, echinoderms display a unique combination of striking regenerative abilities and diversity of useful experimental models, although still largely unexplored. Therefore, the brittle star Amphiura filiformis and the starfish Echinaster sepositus were here used to comparatively investigate the main repair phase events after injury as well as the presence and expression of immune system and extracellular matrix (i.e. collagen) molecules using both microscopy and molecular tools. Our results showed that emergency reaction and re-epithelialisation are similar in both echinoderm models, being faster and more effective than in mammals. Moreover, in comparison to the latter, both echinoderms showed delayed and less abundant collagen deposition at the wound site (absence of fibrosis). The gene expression patterns of molecules related to the immune response, such as Ese-fib-like (starfishes) and Afi-ficolin (brittle stars), were described for the first time during echinoderm regeneration providing promising starting points to investigate the immune system role in these regeneration models. Overall, the similarities in repair events and timing within the echinoderms and the differences with what has been reported in mammals suggest that effective repair processes in echinoderms play an important role for their subsequent ability to regenerate. Targeted molecular and functional analyses will shed light on the evolution of these abilities in the deuterostomian lineage.


Assuntos
Extremidades/fisiologia , Regeneração/fisiologia , Estrelas-do-Mar/fisiologia , Animais , Colágeno/metabolismo , Epiderme/ultraestrutura , Proteínas da Matriz Extracelular/metabolismo , Regulação da Expressão Gênica , Estudos de Associação Genética , Microscopia Eletrônica , Regeneração/genética , Regeneração/imunologia , Especificidade da Espécie , Estrelas-do-Mar/genética , Estrelas-do-Mar/imunologia , Fatores de Transcrição/fisiologia , Cicatrização/fisiologia
19.
Development ; 145(2)2018 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-29358213

RESUMO

Specification of the germ cell lineage is required for sexual reproduction in animals. The mechanism of germ cell specification varies among animals but roughly clusters into either inherited or inductive mechanisms. The inductive mechanism, the use of cell-cell interactions for germ cell specification, appears to be the ancestral mechanism in animal phylogeny, yet the pathways responsible for this process are only recently surfacing. Here, we show that germ cell factors in the sea star initially are present broadly, then become restricted dorsally and then in the left side of the embryo where the germ cells form a posterior enterocoel. We find that Nodal signaling is required for the restriction of two germ cell factors, Nanos and Vasa, during the early development of this animal. We learned that Nodal inhibits germ cell factor accumulation in three ways including: inhibition of specific transcription, degradation of specific mRNAs and inhibition of tissue morphogenesis. These results document a signaling mechanism required for the sequential restriction of germ cell factors, which causes a specific set of embryonic cells to become the primordial germ cells.


Assuntos
Proteína Nodal/metabolismo , Estrelas-do-Mar/embriologia , Animais , Apoptose , Linhagem da Célula , RNA Helicases DEAD-box/metabolismo , Evolução Molecular , Regulação da Expressão Gênica no Desenvolvimento , Células Germinativas/metabolismo , Modelos Biológicos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais , Estrelas-do-Mar/genética , Estrelas-do-Mar/metabolismo
20.
Mar Genomics ; 37: 92-96, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28899644

RESUMO

Starfish (Phylum Echinodermata) are of interest from an evolutionary perspective because as deuterostomian invertebrates they occupy an "intermediate" phylogenetic position with respect to chordates (e.g. vertebrates) and protostomian invertebrates (e.g. Drosophila). Furthermore, starfish are model organisms for research on fertilization, embryonic development, innate immunity and tissue regeneration. However, large-scale molecular data for starfish tissues/organs are limited. To provide a comprehensive genetic resource for the starfish Patiria pectinifera, we report de novo transcriptome assemblies and global gene expression analysis for six P. pectinifera tissues/organs - body wall (BW), coelomic epithelium (CE), tube feet (TF), stomach (SM), pyloric caeca (PC) and gonad (GN). A total of 408 million high-quality reads obtained from six cDNA libraries were assembled de novo using Trinity, resulting in a total of 549,598 contigs with a mean length of 835 nucleotides (nt), an N50 of 1473nt, and GC ratio of 42.5%. A total of 126,136 contigs (22.9%) were obtained as predicted open reading frames (ORFs) by TransDecoder, of which 102,187 were annotated with NCBI non-redundant (NR) hits, and 51,075 and 10,963 were annotated with Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) using the Blast2GO program, respectively. Gene expression analysis revealed that tissues/organs are grouped into three clusters: BW/CE/TF, SM/PC, and GN, which likely reflect functional relationships. 2408, 8560, 2687, 1727, 3321, and 2667 specifically expressed genes were identified for BW, GN, PC, CE, SM and TF, respectively, using the ROKU method. This study provides a valuable transcriptome resource and novel molecular insights into the functional biology of different tissues/organs in starfish as a model organism.


Assuntos
Estrelas-do-Mar/genética , Transcriptoma , Animais , Perfilação da Expressão Gênica
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