45 research outputs found
Gonadotropin-Releasing Hormone and Adipokinetic Hormone Signaling Systems Share a Common Evolutionary Origin
Get PDFGonadotropin-releasing hormone (GnRH) is a critical and central hormone that regulates vertebrate reproduction. The high conservation of GnRH signaling within the chordates (deuterostomians) raises the important question as to whether its appearance might date back prior to the divergence of protostomian and deuterostomian lineages, about 700 million years ago. This leads to several important questions regarding the evolution of the GnRH family. Has GnRH been retained in most protostomian lineages? And was regulation of reproduction already a function of ancestral GnRH? The first question can undoubtedly be answered affirmatively since several GnRH-like sequences have been found in wide variety of protostomian and deuterostomian phyla. However, based on their different primary functions in different phyla â which implies a less unanimous answer on the second question â consistency in the nomenclature of this peptide family has been lost. A comparative and phylogenetic approach shows that the ecdysozoan adipokinetic hormones (AKHs), lophotrochozoan GnRHs and chordate GnRHs are structurally related and suggests that they all originate from a common ancestor. This review supports the view that the AKHâGnRH signaling system probably arose very early in metazoan evolution, prior to the divergence of protostomians and deuterostomians
Potential conservation of circadian clock proteins in the phylum Nematoda as revealed by bioinformatic searches
Get PDFAlthough several circadian rhythms have been described in C. elegans, its molecular clock remains elusive. In this work we employed a novel bioinformatic approach, applying probabilistic methodologies, to search for circadian clock proteins of several of the best studied circadian model organisms of different taxa (Mus musculus, Drosophila melanogaster, Neurospora crassa, Arabidopsis thaliana and Synechoccocus elongatus) in the proteomes of C. elegans and other members of the phylum Nematoda. With this approach we found that the Nematoda contain proteins most related to the core and accessory proteins of the insect and mammalian clocks, which provide new insights into the nematode clock and the evolution of the circadian system.Fil: Romanowski, AndrĂ©s. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Instituto de Investigaciones BioquĂmicas de Buenos Aires. FundaciĂłn Instituto Leloir. Instituto de Investigaciones BioquĂmicas de Buenos Aires; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa. Laboratorio de CronobiologĂa; ArgentinaFil: Garavaglia, MatĂas Javier. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa. Laboratorio de Ing.genĂ©tica y Biolog.molecular y Celular. Area Virus de Insectos; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Goya, MarĂa Eugenia. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa. Laboratorio de CronobiologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Ghiringhelli, Pablo Daniel. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa. Laboratorio de Ing.genĂ©tica y Biolog.molecular y Celular. Area Virus de Insectos; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Golombek, Diego Andres. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa. Laboratorio de CronobiologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
Neural Architecture of Hunger-Dependent Multisensory Decision Making in C. elegans
Get PDFLittle is known about how animals integrate multiple sensory inputs in natural environments to balance avoidance of danger with approach to things of value. Furthermore, the mechanistic link between internal physiological state and threat-reward decision making remains poorly understood. Here we confronted C. elegans worms with the decision whether to cross a hyperosmotic barrier presenting the threat of desiccation to reach a source of food odor. We identified a specific interneuron that controls this decision via top-down extrasynaptic aminergic potentiation of the primary osmosensory neurons to increase their sensitivity to the barrier. We also establish that food deprivation increases the worm's willingness to cross the dangerous barrier by suppressing this pathway. These studies reveal a potentially general neural circuit architecture for internal state control of threat-reward decision making
Nematode and Arthropod Genomes Provide New Insights into the Evolution of Class 2 B1 GPCRs
Get PDFNematodes and arthropods are the most speciose animal groups and possess Class 2 B1 G-protein coupled receptors
(GPCRs). Existing models of invertebrate Class 2 B1 GPCR evolution are mainly centered on Caenorhabditis elegans and
Drosophila melanogaster and a few other nematode and arthropod representatives. The present study reevaluates the
evolution of metazoan Class 2 B1 GPCRs and orthologues by exploring the receptors in several nematode and arthropod
genomes and comparing them to the human receptors. Three novel receptor phylogenetic clusters were identified and
designated cluster A, cluster B and PDF-R-related cluster. Clusters A and B were identified in several nematode and
arthropod genomes but were absent from D. melanogaster and Culicidae genomes, whereas the majority of the members of
the PDF-R-related cluster were from nematodes. Cluster A receptors were nematode and arthropod-specific but shared a
conserved gene environment with human receptor loci. Cluster B members were orthologous to human GCGR, PTHR and
Secretin members with which they probably shared a common origin. PDF-R and PDF-R related clusters were present in
representatives of both nematodes and arthropods. The results of comparative analysis of GPCR evolution and diversity in
protostomes confirm previous notions that C. elegans and D. melanogaster genomes are not good representatives of
nematode and arthropod phyla. We hypothesize that at least four ancestral Class 2 B1 genes emerged early in the metazoan
radiation, which after the protostome-deuterostome split underwent distinct selective pressures that resulted in duplication
and deletion events that originated the current Class 2 B1 GPCRs in nematode and arthropod genomes.This work was supported by the Portuguese Foundation for Science and Technology (FCT) project PTDC/BIA-BCM/114395/2009, by the European
Regional Development Fund through COMPETE and FCT under the project ââPEst-C/MAR/LA0015/2011.ââ RCF is in receipt of an FCT grant (SFRH/BPD/89811/2012)
and JCRC is supported by auxiliary research contract FCT Pluriannual funds attributed to CCMAR. The funders had no role in study design, data collection and
analysis, decision to publish, or preparation of the manuscript
Background matching in the brown shrimp Crangon crangon : adaptive camouflage and behavioural-plasticity
Get PDFA combination of burrowing behaviour and very efficient background matching makes the brown shrimp Crangon crangon almost invisible to potential predators and preys. This raises questions on how shrimp succeed in concealing themselves in the heterogeneous and dynamic estuarine habitats they inhabit and what type of environmental variables and behavioural factors affect their colour change abilities. Using a series of behavioural experiments, we show that the brown shrimp is capable of repeated fast colour adaptations (20% change in dark pigment cover within one hour) and that its background matching ability is mainly influenced by illumination and sediment colour. Novel insights are provided on the occurrence of non-adaptive (possibly stress) responses to background changes after long-time exposure to a constant background colour or during unfavourable conditions for burying. Shrimp showed high levels of intra- and inter-individual variation, demonstrating a complex balance between behavioural-plasticity and environmental adaptation. As such, the study of crustacean colour changes represents a valuable opportunity to investigate colour adaptations in dynamic habitats and can help us to identify the mayor environmental and behavioural factors influencing the evolution of animal background matching
The functional characterization of the pigment dispersing factor (PDF) pathway in the nematode Caenorhabditis elegans.
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In this study, C. elegans was used to uncover the functions of three related neuropeptidesof the pigment dispersing hormone (PDH) family and of their receptors. The first members of the PDH neuropeptidefamily were discovered in crustaceans where they are exclusively called PDHs. The subsequently discovered homologues in insectsand nematodes are called pigment dispersing factors (PDFs). The neuropeptides PDF-1a, PDF-1b (encoded bythe pdf-1 gene) and PDF-2 (encoded bythe pdf-2 gene) and their receptorsPDFR-1a, b and c (isoforms encoded by the pdfr-1gene) are part of the PDF signaling pathway in C. elegans. Whereas PDH incrustaceans and PDF in insects are respectively engaged in pigment dispersionand circadian rhythms, C. elegans doesnot display pigment dispersion and until recently, was believed not to displaycircadian rhythms either. This projectaimed to characterize the PDF signaling pathway in C. elegans by 1) comparing the PDF neuropeptides, precursorproteins and receptors to crustacean PDH proteins and receptors at the level ofamino acid sequence as well as assessing the pigment dispersing ability of the C. elegans peptides in a crustaceanmodel, the shrimp Palaemon pacificus,2) studying behavioral traits of mutants wherein the pdf genes are compromised and 3) studying expression of the pdf genes in a site and time specificmanner.Althoughoverall precursor- and receptor structures are well conserved, it is clear fromthe comparison of amino acid sequences and length of the C. elegans PDF peptides that they deviate considerably from crustaceanPDH peptides. Although, PDF-1a and bboth are able to cause pigment dispersion in the shrimp P. pacificus, PDF-2 is not. This characteristic can be attributed to the N-terminal N-ELIN sequencewhich is generally conserved in crustacean PDH peptides and partially missingin PDF-2. Priorto the start of the present study, it was already known that pdf-1 is involved in the regulation oflocomotion sinceabsence of pdf-1 resultsin a reduction of speed and increase of reversals in crawling animals. In this study, a pdfr-1 mutant was generated and additionally, pdf-2 mutants became available for research. We here demonstrate that apart from pdf-1, also pdf-2 and pdfr-1 areinvolved in the regulation of locomotion as pdfr-1mutants display a similar but stronger crawling phenotype as pdf-1 animals. pdf-2 onthe other hand, is specifically involved in inducing reversals rather thanlocomotion speed. Moreover, PDFsignaling regulates another locomotion gait, namely swimming, as both pdf-1 and pdfr-1 mutants display reduced swimming activity. Although pdf-1expression levels do not vary during the course of the day, there are strongpresumptions that pdf-1 is alsoengaged in the regulation of circadian activity rhythms based on circadianactivity levels. The reintroduction of the different PDFreceptor isoforms in pdfr-1 mutants showsthat PDFR-1a, b and c are all involved in the regulation of locomotion. Transgenic C. elegans expressing fluorescent reporter proteins reveal that pdfr-1 is expressed in both neurons andbody wall muscles, two different tissues that are generally known for theirinvolvement in locomotion. Althoughmuscle specific expression of any of the three receptor isoforms was notsufficient to restore the diminished swimming activity in pdfr-1 mutants, pan-neuronal expression did restore activitylevels, suggesting that locomotion is mainly under neuronal control. Moreover, by studying body wall musclestructure, we show that the overall muscle structure is intact in pdfr-1 mutants. Forthe first time, we provide evidence that PDF signaling regulates reproductiveprocesses in both self-fertilizing hermaphrodites and in males. Although the brood sizes of hermaphroditesremain unchanged in pdf-1, pdf-2 and pdfr-1 mutants, the overall timing of egg-laying in pdf-1, pdf-2 and pdf-1/pdf-2 doublemutantsis delayed. pdfr-1 mutants seem superficially unaffected but in fact retainmore eggs in their uterus compared to wild type worms. A model including stimulation of egg-layingthrough the PDF peptides, PDFR-1a and b and the G-protein Gαs, andinhibition of egg-laying through the constitutively active PDFR-1c and Gαi/ois proposed based on these results. Alsomales are dependent on proper PDF signaling: matings with pdf-1, pdf-2 and pdfr-1 males show a reduced success rate. Overall,the PDF signaling system in C. elegansis similar to and shares functions with the corresponding systems incrustaceans and insects. In addition,new kinds of behavior such as male mating behavior could be functionally linkedto the PDF pathway. The extensivegenetic toolkit available for C. elegansallows further dissection of these in the future.nrpages: 173status: publishe
Implementatie vastgoedbeleid woningcorporaties; een voorbeeld van gedegen vastgoedbeleid
No full textSignalling through pigment dispersing hormone-like peptides in invertebrates
No full textDuring recent decades, several research teams engaged in unraveling the molecular structure and the physiological significance of pigment dispersing hormone-like peptides, particularly with respect to colour change and biological rhythms. In this review, we first summarise the entire history of pigment dispersing hormone-like peptide research, thus providing a steppingstone for those who are curious about this growing area of interest. Next, we try to bring order in the plethora of experimental data on the molecular structure of the various peptides and receptors and also discuss immunolocalisation, time-related expression and suggested functions in crustaceans, insects and nematodes. In addition, a brief comparison with the vertebrate system is made
