Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 123
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-36379379

RESUMO

Transbranchial transport processes are responsible for the homeostatic regulation of most essential physiological functions in aquatic crustaceans. Due to their widespread use as laboratory models, brachyuran crabs are commonly used to predict how other decapod crustaceans respond to environmental stressors including ocean acidification and warming waters. Non-brachyuran species such as the economically-valuable American lobster, Homarus americanus, possess trichobranchiate gills and epipodites that are known to be anatomically distinct from the phyllobranchiate gills of brachyurans; however, studies have yet to define their potential physiological differences. Our results indicate that the pleuro-, arthro-, and podobranch gills of the lobster are functionally homogenous and similar to the respiratory gills of brachyurans as indicated by equivalent rates of H+Eq., CO2, HCO3-, and ammonia transport and mRNA expression of related transporters and enzymes. The epipodites were found to be functionally distinct, being capable of greater individual rates of H+Eq., CO2, and ammonia transport despite mRNA transcript levels of related transporters and enzymes being only a fraction found in the gills. Collectively, mathematical estimates infer that the gills are responsible for 91% of the lobster's branchial HCO3- accumulation whereas the epipodites are responsible for 66% of branchial ammonia excretion suggesting different mechanisms exist in these tissues. Furthermore, the greater metabolic rate and amino acid catabolism in the epipodites suggest that the tissue much of the CO2 and ammonia excreted by this tissue originates intracellularly rather than systemically. These results provide evidence that non-brachyuran species must be carefully compared to brachyuran models.


Assuntos
Braquiúros , Nephropidae , Animais , Nephropidae/genética , Concentração de Íons de Hidrogênio , Brânquias/metabolismo , Amônia/metabolismo , Dióxido de Carbono/metabolismo , Água do Mar/química , Proteínas de Membrana Transportadoras/metabolismo , Braquiúros/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
2.
BMC Genomics ; 23(1): 750, 2022 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-36368918

RESUMO

BACKGROUND: Evolutionary divergence and speciation often occur at a slower rate in the marine realm due to the higher potential for long-distance reproductive interaction through larval dispersal. One common evolutionary pattern in the Indo-Pacific, is divergence of populations and species at the peripheries of widely-distributed organisms. However, the evolutionary and demographic histories of such divergence are yet to be well understood. Here we address these issues by coupling genome-wide SNP data with mitochondrial DNA sequences to test the patterns of genetic divergence and possible secondary contact among geographically distant populations of the highly valuable spiny lobster Panulirus homarus species complex, distributed widely through the Indo-Pacific, from South Africa to the Marquesas Islands. RESULT: After stringent filtering, 2020 SNPs were used for population genetic and demographic analyses, revealing strong regional structure (FST = 0.148, P < 0001), superficially in accordance with previous analyses. However, detailed demographic analyses supported a much more complex evolutionary history of these populations, including a hybrid origin of a North-West Indian Ocean (NWIO) population, which has previously been discriminated morphologically, but not genetically. The best-supported demographic models suggested that the current genetic relationships among populations were due to a complex series of past divergences followed by asymmetric migration in more recent times. CONCLUSION: Overall, this study suggests that alternating periods of marine divergence and gene flow have driven the current genetic patterns observed in this lobster and may help explain the observed wider patterns of marine species diversity in the Indo-Pacific.


Assuntos
Palinuridae , Animais , Palinuridae/genética , Nephropidae/genética , Polimorfismo de Nucleotídeo Único , Genoma , Fluxo Gênico , DNA Mitocondrial/genética , Filogenia , Variação Genética
3.
Mol Ecol ; 31(20): 5182-5200, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35960266

RESUMO

In marine species experiencing intense fishing pressures, knowledge of genetic structure and local adaptation represent a critical information to assist sustainable management. In this study, we performed a landscape genomics analysis in the American lobster to investigate the issues pertaining to the consequences of making use of putative adaptive loci to reliably infer population structure and thus more rigorously delineating biological management units in marine exploited species. Toward this end, we genotyped 14,893 single nucleotide polymorphism (SNPs) in 4190 lobsters sampled across 96 sampling sites distributed along 1000 km in the northwest Atlantic in both Canada and the USA. As typical for most marine species, we observed a weak, albeit highly significant genetic structure. We also found that adaptive genetic variation allows detecting fine-scale population structure not resolved by neutral genetic variation alone. Using the recent genome assembly of the American lobster, we were able to map and annotate several SNPs located in functional genes potentially implicated in adaptive processes such as thermal stress response, salinity tolerance and growth metabolism pathways. Taken together, our study indicates that weak population structure in high gene flow systems can be resolved at various spatial scales, and that putatively adaptive genetic variation can substantially enhance the delineation of biological management units of marine exploited species.


Assuntos
Genômica , Nephropidae , Animais , Fluxo Gênico , Genótipo , Nephropidae/genética , Polimorfismo de Nucleotídeo Único/genética
4.
PeerJ ; 10: e12744, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35047236

RESUMO

To date, 19 species of spiny lobsters from the genus Panulirus have been discovered, of which only P. japonicus, P. penicilatus, P. stimpsoni, and P. versicolor have been documented in South Korean waters. In this study, we aimed to identify and update the current list of spiny lobster species that inhabit South Korean waters based on the morphological features and the phylogenetic profile of cytochrome oxidase I (COI) of mitochondrial DNA (mtDNA). Spiny lobsters were collected from the southern and eastern coasts of Jeju Island, South Korea. Phylogenetic analyses were performed using neighbor-joining (NJ), maximum likelihood (ML), and Bayesian inference (BI) methods. The ML tree was used to determine the spiny lobster lineages, thereby clustering the 17 specimens collected in this study into clades A, B, C, and D, which were reciprocally monophyletic with P. japonicus, P. homarus homarus, P. longipes, and P. stimpsoni, respectively. These clades were also supported by morphological examinations. Interestingly, morphological variations, including the connected pleural and transverse groove at the third abdominal somite, were observed in four specimens that were genetically confirmed as P. japonicus. This finding is novel within the P. japonicus taxonomical reports. Additionally, this study updates the documentation of spiny lobsters inhabiting South Korean waters as P. longipes and P. homarus homarus were recorded for the first time in this region.


Assuntos
Palinuridae , Animais , Palinuridae/genética , Filogenia , Nephropidae/genética , Teorema de Bayes , Código de Barras de DNA Taxonômico , DNA Mitocondrial/genética
5.
Artigo em Inglês | MEDLINE | ID: mdl-34688176

RESUMO

Chlorpyrifos is an organophosphate that is currently used to reduce arthropod pests for the protection of agricultural crops. Coastal marine ecosystems may be exposed to agricultural pesticides via runoff and pesticide exposure can impact the health and survival of non-target species such as the American lobster (Homarus americanus). In the current study, the gene expression changes of H. americanus stage IV larvae were evaluated to understand the physiological mechanisms affected by exposure to sublethal concentrations of chlorpyrifos. After 48 h chlorpyrifos exposure, surviving lobsters were processed for Illumina RNA sequencing (RNA-seq). Genes of interest that showed significant changes using RNA-seq were verified using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). Analysis of RNA-seq and the confirmation of gene expression patterns via RT-qPCR found altered expression in genes related to stress response (glutathione peroxidase 3 and heat shock protein 60), hypoxia response (hairy, astakine 2, hemocyanin), moulting (cytochrome P450 307a1 and chitinase), and immunity (astakine 2) pathways. Changes to gene expression were most notable in lobsters exposed to 0.57 µg/L chlorpyrifos.


Assuntos
Clorpirifos , Praguicidas , Animais , Clorpirifos/toxicidade , Ecossistema , Nephropidae/genética , Praguicidas/toxicidade , Transcriptoma
6.
Int J Mol Sci ; 22(16)2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34445418

RESUMO

Central pattern generators produce rhythmic behaviors independently of sensory input; however, their outputs can be modulated by neuropeptides, thereby allowing for functional flexibility. We investigated the effects of C-type allatostatins (AST-C) on the cardiac ganglion (CG), which is the central pattern generator that controls the heart of the American lobster, Homarus americanus, to identify the biological mechanism underlying the significant variability in individual responses to AST-C. We proposed that the presence of multiple receptors, and thus differential receptor distribution, was at least partly responsible for this observed variability. Using transcriptome mining and PCR-based cloning, we identified four AST-C receptors (ASTCRs) in the CG; we then characterized their cellular localization, binding potential, and functional activation. Only two of the four receptors, ASTCR1 and ASTCR2, were fully functional GPCRs that targeted to the cell surface and were activated by AST-C peptides in our insect cell expression system. All four, however, were amplified from CG cDNAs. Following the confirmation of ASTCR expression, we used physiological and bioinformatic techniques to correlate receptor expression with cardiac responses to AST-C across individuals. Expression of ASTCR1 in the CG showed a negative correlation with increasing contraction amplitude in response to AST-C perfusion through the lobster heart, suggesting that the differential expression of ASTCRs within the CG is partly responsible for the specific physiological response to AST-C exhibited by a given individual lobster.


Assuntos
Perfilação da Expressão Gênica/métodos , Nephropidae/genética , Neuropeptídeos/farmacologia , Receptores de Neuropeptídeos/genética , Receptores de Neuropeptídeos/metabolismo , Animais , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/metabolismo , Sistema Cardiovascular/metabolismo , Membrana Celular/metabolismo , Clonagem Molecular , Mineração de Dados , Bases de Dados Genéticas , Regulação da Expressão Gênica/efeitos dos fármacos , Miocárdio/metabolismo , Nephropidae/efeitos dos fármacos , Nephropidae/metabolismo , Análise de Sequência de RNA , Células Sf9 , Distribuição Tecidual
7.
Sci Adv ; 7(26)2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34162536

RESUMO

The American lobster, Homarus americanus, is integral to marine ecosystems and supports an important commercial fishery. This iconic species also serves as a valuable model for deciphering neural networks controlling rhythmic motor patterns and olfaction. Here, we report a high-quality draft assembly of the H. americanus genome with 25,284 predicted gene models. Analysis of the neural gene complement revealed extraordinary development of the chemosensory machinery, including a profound diversification of ligand-gated ion channels and secretory molecules. The discovery of a novel class of chimeric receptors coupling pattern recognition and neurotransmitter binding suggests a deep integration between the neural and immune systems. A robust repertoire of genes involved in innate immunity, genome stability, cell survival, chemical defense, and cuticle formation represents a diversity of defense mechanisms essential to thrive in the benthic marine environment. Together, these unique evolutionary adaptations contribute to the longevity and ecological success of this long-lived benthic predator.


Assuntos
Longevidade , Nephropidae , Animais , Ecossistema , Longevidade/genética , Nephropidae/genética , Nephropidae/metabolismo , Sistema Nervoso
8.
Invert Neurosci ; 20(4): 24, 2020 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-33244646

RESUMO

Over the past decade, many new peptide families have been identified via in silico analyses of genomic and transcriptomic datasets. While various molecular and biochemical methods have confirmed the existence of some of these new groups, others remain in silico discoveries of computationally assembled sequences only. An example of the latter are the CCRFamides, named for the predicted presence of two pairs of disulfide bonded cysteine residues and an amidated arginine-phenylalanine carboxyl-terminus in family members, which have been identified from annelid, molluscan, and arthropod genomes/transcriptomes, but for which no precursor protein-encoding cDNAs have been cloned. Using routine transcriptome mining methods, we identified four Homarus americanus (American lobster) CCRFamide transcripts that share high sequence identity across the predicted open reading frames but more limited conservation in their 5' terminal ends, suggesting the Homarus gene undergoes alternative splicing. RT-PCR profiling using primers designed to amplify an internal fragment common to all of the transcripts revealed expression in the supraoesophageal ganglion (brain), eyestalk ganglia, and cardiac ganglion. Variant specific profiling revealed a similar profile for variant 1, eyestalk ganglia specific expression of variant 2, and an absence of variant 3 expression in the cDNAs examined. The broad distribution of CCRFamide transcript expression in the H. americanus nervous system suggests a potential role as a locally released and/or circulating neuropeptide. This is the first report of the cloning of a CCRFamide-encoding cDNA from any species, and as such, provides the first non-in silico support for the existence of this invertebrate peptide family.


Assuntos
Proteínas de Artrópodes/genética , Nephropidae/genética , Neuropeptídeos/genética , Animais , Encéfalo , Clonagem Molecular , Olho , Gânglios dos Invertebrados , Coração , Transcriptoma
9.
Artigo em Inglês | MEDLINE | ID: mdl-32777773

RESUMO

The American lobster (Homarus americanus) is one of the most iconic and economically valuable fishery species in the Northwestern Atlantic. Surface ocean temperatures are rapidly increasing across much of the species' range, raising concern about resiliency in the face of environmental change. Warmer temperatures accelerate rates of larval development and enhance survival to the postlarval stage, but the potential costs at the molecular level have rarely been addressed. We explored how exposure to current summer temperatures (16 °C) or temperature regimes mimicking projected moderate or extreme warming scenarios (18 °C and 22 °C, respectively) for the Gulf of Maine during development influences the postlarval lobster transcriptome. After de novo assembling the transcriptome, we identified 2542 differentially expressed (DE; adjusted p < 0.05) transcripts in postlarvae exposed to 16 °C vs. 22 °C, and 422 DE transcripts in postlarvae reared at 16 °C vs. 18 °C. Lobsters reared at 16 °C significantly over-expressed transcripts related to cuticle formation and the immune response up to 14.4- and 8.5-fold respectively, relative to those reared at both 18 °C and 22 °C. In contrast, the expression of transcripts affiliated with metabolism increased up to 7.1-fold as treatment temperature increased. These results suggest that lobsters exposed to projected warming scenarios during development experience a shift in the transcriptome that reflects a potential trade-off between maintaining immune defenses and sustaining increased physiological rates under a warming environment. This could have major implications for post-settlement survival through increased risk of mortality due to disease and/or starvation if energetic demands cannot be met.


Assuntos
Metabolismo Energético , Regulação da Expressão Gênica , Larva/genética , Nephropidae/genética , Estações do Ano , Temperatura , Transcriptoma , Animais , Larva/crescimento & desenvolvimento , Nephropidae/crescimento & desenvolvimento , Oceanos e Mares
10.
Food Chem ; 332: 127389, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32645674

RESUMO

Food allergens that cause anaphylactic reactions have become an important health problem worldwide. Among them, shrimp is a popular seafood in many cuisines. The best way to avoid allergic reactions is to mitigate the intake of food allergens. In this study, a loop-mediated isothermal amplification (LAMP) assay was developed for the detection of shrimp DNA. Using LAMP primers, the identification of shrimp DNA by the LAMP assay was specific and rapid (within 30 min). It exhibited no cross-reaction with the DNA of other Crustacea, including crabs and lobster, and at least 0.01% shrimp DNA existed in the test sample. Additionally, the sensitivity of LAMP for detecting shrimp DNA was 100-fold greater than that of conventional PCR. LAMP for the detection of shrimp DNA was reproducible regardless of whether the genomic DNA was extracted from boiled, steamed or roasted shrimp samples. In summary, the LAMP assay established herein not only could be potentially used for diagnosing shrimp DNA but could also be applicable for identifying shrimp allergens in commercial food products in marketplaces.


Assuntos
Alérgenos/análise , Técnicas de Amplificação de Ácido Nucleico/métodos , Penaeidae/genética , Alimentos Marinhos/análise , Alérgenos/genética , Animais , Sequência de Bases , Braquiúros/genética , Primers do DNA/metabolismo , Nephropidae/genética , RNA Ribossômico 16S/química , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Alinhamento de Sequência
11.
Sci Rep ; 10(1): 7781, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385382

RESUMO

American lobsters (Homarus americanus) imported live into Europe as a seafood commodity have occasionally been released or escaped into the wild, within the range of an allopatric congener, the European lobster (H. gammarus). In addition to disease and competition, introduced lobsters threaten native populations through hybridisation, but morphological discriminants used for species identification are unable to discern hybrids, so molecular methods are required. We tested an array of 79 single nucleotide polymorphisms (SNPs) for their utility to distinguish 1,308 H. gammarus from 38 H. americanus and 30 hybrid offspring from an American female captured in Sweden. These loci provide powerful species assignment in Homarus, enabling the robust identification of hybrid and American individuals among a survey of European stock. Moreover, a subset panel of the 12 most powerful SNPs is sufficient to separate the two pure species, even when tissues have been cooked, and can detect the introduced component of hybrids. We conclude that these SNP loci can unambiguously identify hybrid lobsters that may be undetectable via basic morphology, and offer a valuable tool to investigate the prevalence of cryptic hybridisation in the wild. Such investigations are required to properly evaluate the potential for introgression of alien genes into European lobster populations.


Assuntos
Cruzamentos Genéticos , Hibridização Genética , Nephropidae/genética , Alelos , Animais , Cruzamento , Europa (Continente) , Genótipo , Nephropidae/classificação , Polimorfismo de Nucleotídeo Único
12.
Sci Rep ; 10(1): 3574, 2020 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-32107415

RESUMO

Crustacean eggs are rare in the fossil record. Here we report the exquisite preservation of a fossil polychelidan embedded within an unbroken nodule from the Middle Jurassic La Voulte-sur-Rhône Lagerstätte (France) and found with hundreds of eggs attached to the pleon. This specimen belongs to a new species, Palaeopolycheles nantosueltae sp. nov. and offers unique clues to discuss the evolution of brooding behaviour in polychelidan lobsters. In contrast to their development, which now relies on a long-lived planktic larval stage that probably did not exist in the early evolutionary steps of the group, the brood size of polychelidan lobsters seems to have remained unchanged and comparatively small since the Jurassic. This finding is at odds with reproductive strategies in other lobster groups, in which a long-lived planktic larval stage is associated with a large brood size.


Assuntos
Nephropidae/classificação , Óvulo/química , Animais , Evolução Biológica , Fósseis/anatomia & histologia , Fósseis/história , França , História Antiga , Nephropidae/anatomia & histologia , Nephropidae/genética , Nephropidae/crescimento & desenvolvimento , Óvulo/classificação , Óvulo/crescimento & desenvolvimento , Paleontologia
13.
PLoS One ; 15(1): e0225807, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31999723

RESUMO

DNA from formalin-preserved tissue could unlock a vast repository of genetic information stored in museums worldwide. However, formaldehyde crosslinks proteins and DNA, and prevents ready amplification and DNA sequencing. Formaldehyde acylation also fragments the DNA. Treatment with proteinase K proteolyzes crosslinked proteins to rescue the DNA, though the process is quite slow. To reduce processing time and improve rescue efficiency, we applied the mechanical energy of a vortex fluidic device (VFD) to drive the catalytic activity of proteinase K and recover DNA from American lobster tissue (Homarus americanus) fixed in 3.7% formalin for >1-year. A scan of VFD rotational speeds identified the optimal rotational speed for recovery of PCR-amplifiable DNA and while 500+ base pairs were sequenced, shorter read lengths were more consistently obtained. This VFD-based method also effectively recovered DNA from formalin-preserved samples. The results provide a roadmap for exploring DNA from millions of historical and even extinct species.


Assuntos
DNA/isolamento & purificação , Formaldeído , Hidrodinâmica , Museus , Fixação de Tecidos , Animais , Sequência de Bases , DNA/genética , Nephropidae/genética , Reação em Cadeia da Polimerase
14.
BMC Genomics ; 20(1): 335, 2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-31053062

RESUMO

BACKGROUND: The recently published complete mitogenome of the European lobster (Homarus gammarus) that was generated using long-range PCR exhibits unusual gene composition (missing nad2) and gene rearrangements among decapod crustaceans with strong implications in crustacean phylogenetics. Such atypical mitochondrial features will benefit greatly from validation with emerging long read sequencing technologies such as Oxford Nanopore that can more accurately identify structural variation. RESULTS: We re-sequenced the H. gammarus mitogenome on an Oxford Nanopore Minion flowcell and performed a long-read only assembly, generating a complete mitogenome assembly for H. gammarus. In contrast to previous reporting, we found an intact mitochondrial nad2 gene in the H. gammarus mitogenome and showed that its gene organization is broadly similar to that of the American lobster (H. americanus) except for the presence of a large tandemly duplicated region with evidence of pseudogenization in one of each duplicated protein-coding genes. CONCLUSIONS: Using the European lobster as an example, we demonstrate the value of Oxford Nanopore long read technology in resolving problematic mitogenome assemblies. The increasing accessibility of Oxford Nanopore technology will make it an attractive and useful tool for evolutionary biologists to verify new and existing unusual mitochondrial gene rearrangements recovered using first and second generation sequencing technologies, particularly those used to make phylogenetic inferences of evolutionary scenarios.


Assuntos
Evolução Biológica , Biologia Computacional/métodos , Duplicação Gênica , Genoma Mitocondrial , Proteínas Mitocondriais/genética , Nanoporos , Nephropidae/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Sequenciamento de Nucleotídeos em Larga Escala , Família Multigênica , Nephropidae/metabolismo , Filogenia , Análise de Sequência de DNA , Homologia de Sequência
15.
PLoS One ; 14(1): e0210492, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30677051

RESUMO

Full-length mitochondrial cytochrome c oxidase I (COI) sequence information from lobster phyllosoma larvae can be difficult to obtain when DNA is degraded or fragmented. Primers that amplify smaller fragments are also more useful in metabarcoding studies. In this study, we developed and tested a method to design a taxon-specific mini-barcode primer set for marine lobsters. The shortest, most informative portion of the COI gene region was identified in silico, and a DNA barcode gap analysis was performed to assess its reliability as species diagnostic marker. Primers were designed, and cross-species amplification success was tested on DNA extracted from a taxonomic range of spiny-, clawed-, slipper- and blind lobsters. The mini-barcode primers successfully amplified both adult and phyllosoma COI fragments, and were able to successfully delimit all species analyzed. Previously published universal primer sets were also tested and sometimes failed to amplify COI from phyllosoma samples. The newly designed taxon-specific mini-barcode primers will increase the success rate of species identification in bulk environmental samples and add to the growing DNA metabarcoding toolkit.


Assuntos
Biomarcadores/análise , Código de Barras de DNA Taxonômico/métodos , Complexo IV da Cadeia de Transporte de Elétrons/genética , Proteínas Mitocondriais/genética , Nephropidae/genética , Animais , Primers do DNA/genética , Nephropidae/classificação , Subunidades Proteicas , Reprodutibilidade dos Testes , Alimentos Marinhos , Especificidade da Espécie
16.
J Exp Biol ; 222(Pt 2)2019 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-30464043

RESUMO

Recent genomic/transcriptomic studies have identified a novel peptide family whose members share the carboxyl terminal sequence -GSEFLamide. However, the presence/identity of the predicted isoforms of this peptide group have yet to be confirmed biochemically, and no physiological function has yet been ascribed to any member of this peptide family. To determine the extent to which GSEFLamides are conserved within the Arthropoda, we searched publicly accessible databases for genomic/transcriptomic evidence of their presence. GSEFLamides appear to be highly conserved within the Arthropoda, with the possible exception of the Insecta, in which sequence evidence was limited to the more basal orders. One crustacean in which GSEFLamides have been predicted using transcriptomics is the lobster, Homarus americanus Expression of the previously published transcriptome-derived sequences was confirmed by reverse transcription (RT)-PCR of brain and eyestalk ganglia cDNAs; mass spectral analyses confirmed the presence of all six of the predicted GSEFLamide isoforms - IGSEFLamide, MGSEFLamide, AMGSEFLamide, VMGSEFLamide, ALGSEFLamide and AVGSEFLamide - in H. americanus brain extracts. AMGSEFLamide, of which there are multiple copies in the cloned transcripts, was the most abundant isoform detected in the brain. Because the GSEFLamides are present in the lobster nervous system, we hypothesized that they might function as neuromodulators, as is common for neuropeptides. We thus asked whether AMGSEFLamide modulates the rhythmic outputs of the cardiac ganglion and the stomatogastric ganglion. Physiological recordings showed that AMGSEFLamide potently modulates the motor patterns produced by both ganglia, suggesting that the GSEFLamides may serve as important and conserved modulators of rhythmic motor activity in arthropods.


Assuntos
Amidas/química , Nephropidae/fisiologia , Rede Nervosa/fisiologia , Neuropeptídeos/genética , Transcriptoma , Sequência de Aminoácidos , Animais , Proteínas de Artrópodes/química , Proteínas de Artrópodes/genética , Nephropidae/genética , Neuropeptídeos/química , Neurotransmissores/química , Neurotransmissores/genética , Alinhamento de Sequência
17.
Mar Genomics ; 41: 19-30, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30031746

RESUMO

Whether cardiac output in decapod crustaceans is under circadian control has long been debated, with mixed evidence for and against the hypothesis. Moreover, the locus of the clock system controlling cardiac activity, if it is under circadian control, is unknown. However, a report that the crayfish heart in organ culture maintains a circadian oscillation in heartbeat frequency suggests the presence of a peripheral pacemaker within the cardiac neuromuscular system itself. Because the decapod heart is neurogenic, with contractions controlled by the five motor and four premotor neurons that make up the cardiac ganglion (CG), a likely locus for a circadian clock is the CG itself. Here, a CG-specific transcriptome was generated for the lobster, Homarus americanus, and was used to assess the presence/absence of transcripts encoding putative clock-related proteins in the ganglion. Using known Homarus brain/eyestalk ganglia clock-related proteins as queries, BLAST searches of the CG transcriptome were conducted for the five proteins that form the core clock, i.e., clock, cryptochrome 2, cycle, period and timeless, as well as for a variety of clock-associated, clock input pathway and clock output pathway proteins. With the exception of pigment dispersing hormone receptor [PDHR], a putative clock output pathway protein, one or more transcripts encoding each of the proteins searched for were identified from the CG assembly; no PDHR-encoding transcripts were found. RT-PCR confirmed the expression of all core clock transcripts in multiple independent CG cDNAs; RNA-Seq data suggest that both the motor and premotor neurons could contribute to the cellular locus of a pacemaker. These data provide support for the possible existence of an intrinsic circadian clock in the H. americanus CG, and form a foundation for guiding future anatomical, molecular and physiological investigations of circadian signaling in the lobster cardiac neuromuscular system.


Assuntos
Relógios Circadianos/genética , Nephropidae/genética , Animais , Proteínas CLOCK/genética , Gânglios/fisiologia , Nephropidae/fisiologia , Transcriptoma
18.
BMC Genomics ; 18(1): 622, 2017 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-28814267

RESUMO

BACKGROUND: The Norway lobster, Nephrops norvegicus, is economically important in European fisheries and is a key organism in local marine ecosystems. Despite multi-faceted scientific interest in this species, our current knowledge of genetic resources in this species remains very limited. Here, we generated a reference de novo transcriptome for N. norvegicus from multiple tissues in both sexes. Bioinformatic analyses were conducted to detect transcripts that were expressed exclusively in either males or females. Patterns were validated via RT-PCR. RESULTS: Sixteen N. norvegicus libraries were sequenced from immature and mature ovary, testis and vas deferens (including the masculinizing androgenic gland). In addition, eyestalk, brain, thoracic ganglia and hepatopancreas tissues were screened in males and both immature and mature females. RNA-Sequencing resulted in >600 million reads. De novo assembly that combined the current dataset with two previously published libraries from eyestalk tissue, yielded a reference transcriptome of 333,225 transcripts with an average size of 708 base pairs (bp), with an N50 of 1272 bp. Sex-specific transcripts were detected primarily in gonads followed by hepatopancreas, brain, thoracic ganglia, and eyestalk, respectively. Candidate transcripts that were expressed exclusively either in males or females were highlighted and the 10 most abundant ones were validated via RT-PCR. Among the most highly expressed genes were Serine threonine protein kinase in testis and Vitellogenin in female hepatopancreas. These results align closely with gene annotation results. Moreover, a differential expression heatmap showed that the majority of differentially expressed transcripts were identified in gonad and eyestalk tissues. Results indicate that sex-specific gene expression patterns in Norway lobster are controlled by differences in gene regulation pattern between males and females in somatic tissues. CONCLUSIONS: The current study presents the first multi-tissue reference transcriptome for the Norway lobster that can be applied to future biological, wild restocking and fisheries studies. Sex-specific markers were mainly expressed in males implying that males may experience stronger selection than females. It is apparent that differential expression is due to sex-specific gene regulatory pathways that are present in somatic tissues and not from effects of genes located on heterogametic sex chromosomes. The N. norvegicus data provide a foundation for future gene-based reproductive studies.


Assuntos
Perfilação da Expressão Gênica , Nephropidae/genética , Caracteres Sexuais , Animais , Feminino , Marcadores Genéticos/genética , Genômica , Masculino , Especificidade de Órgãos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
19.
Mol Ecol ; 26(24): 6767-6783, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28658525

RESUMO

Using massively parallel sequencing data from two species with different life history traits, American lobster (Homarus americanus) and Arctic Char (Salvelinus alpinus), we highlight how an unbalanced sex ratio in the samples and a few sex-linked markers may lead to false interpretations of population structure and thus to potentially erroneous management recommendations. Here, multivariate analyses revealed two genetic clusters separating samples by sex instead of by expected spatial variation: inshore and offshore locations in lobster, or east and west locations in Arctic Char. To further investigate this, we created several subsamples artificially varying the sex ratio in the inshore/offshore and east/west groups and then demonstrated that significant genetic differentiation could be observed despite panmixia in lobster, and that FST values were overestimated in Arctic Char. This pattern was due to 12 and 94 sex-linked markers driving differentiation for lobster and Arctic Char, respectively. Removing sex-linked markers led to nonsignificant genetic structure in lobster and a more accurate estimation of FST in Arctic Char. The locations of these markers and putative identities of genes containing or nearby the markers were determined using available transcriptomic and genomic data, and this provided new information related to sex determination in both species. Given that only 9.6% of all marine/diadromous population genomic studies to date have reported sex information, we urge researchers to collect and consider individual sex information. Sex information is therefore relevant for avoiding unexpected biases due to sex-linked markers as well as for improving our knowledge of sex determination systems in nonmodel species.


Assuntos
Genética Populacional , Sequenciamento de Nucleotídeos em Larga Escala , Nephropidae/genética , Razão de Masculinidade , Truta/genética , Animais , Feminino , Marcadores Genéticos , Masculino , Análise Multivariada , Polimorfismo de Nucleotídeo Único , Viés de Seleção
20.
Gen Comp Endocrinol ; 243: 96-119, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-27823957

RESUMO

In silico transcriptome mining is a powerful tool for crustacean peptidome prediction. Using homology-based BLAST searches and a simple bioinformatics workflow, large peptidomes have recently been predicted for a variety of crustaceans, including the lobster, Homarus americanus. Interestingly, no in silico studies have been conducted on the eyestalk ganglia (lamina ganglionaris, medulla externa, medulla interna and medulla terminalis) of the lobster, although the eyestalk is the location of a major neuroendocrine complex, i.e., the X-organ-sinus gland system. Here, an H. americanus eyestalk ganglia-specific transcriptome was produced using the de novo assembler Trinity. This transcriptome was generated from 130,973,220 Illumina reads and consists of 147,542 unique contigs. Eighty-nine neuropeptide-encoding transcripts were identified from this dataset, allowing for the deduction of 62 distinct pre/preprohormones. Two hundred sixty-two neuropeptides were predicted from this set of precursors; the peptides include members of the adipokinetic hormone-corazonin-like peptide, allatostatin A, allatostatin B, allatostatin C, bursicon α, CCHamide, corazonin, crustacean cardioactive peptide, crustacean hyperglycemic hormone (CHH), CHH precursor-related peptide, diuretic hormone 31, diuretic hormone 44, eclosion hormone, elevenin, FMRFamide-like peptide, glycoprotein hormone α2, glycoprotein hormone ß5, GSEFLamide, intocin, leucokinin, molt-inhibiting hormone, myosuppressin, neuroparsin, neuropeptide F, orcokinin, orcomyotropin, pigment dispersing hormone, proctolin, pyrokinin, red pigment concentrating hormone, RYamide, short neuropeptide F, SIFamide, sulfakinin, tachykinin-related peptide and trissin families. The predicted peptides expand the H. americanus eyestalk ganglia neuropeptidome approximately 7-fold, and include 78 peptides new to the lobster. The transcriptome and predicted neuropeptidome described here provide new resources for investigating peptidergic signaling within/from the lobster eyestalk ganglia.


Assuntos
Biologia Computacional/métodos , Olho/metabolismo , Gânglios/metabolismo , Nephropidae/genética , Proteínas do Tecido Nervoso/genética , Neuropeptídeos/análise , Transcriptoma , Sequência de Aminoácidos , Animais , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/metabolismo , Olho/crescimento & desenvolvimento , Gânglios/crescimento & desenvolvimento , Nephropidae/crescimento & desenvolvimento , Nephropidae/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Proteoma/análise , Homologia de Sequência de Aminoácidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA