Identification of novel neuropeptides in the ventral nerve cord ganglia and their targets in an annelid worm, Eisenia fetida

Division of Neurobiology Department of Biology II and Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universitat Munich, D-82152 Martinsried, Germany.
The Journal of Comparative Neurology (Impact Factor: 3.23). 06/2009; 514(6):spc1. DOI: 10.1002/cne.22071
Source: PubMed


Periviscerokinins (PVKs) and pyrokinins (PKs) are neuropeptides known in several arthropod species. Sequence homology of these peptides with the molluscan small cardioactive peptides reveals that the occurrence of PVKs and PKs is not restricted to arthropods. Our study focuses on the biochemical and immunocytochemical identification of neuropeptides with sequence homology to PVKs and PKs in the central and peripheral nervous system of the earthworm Eisenia fetida. By means of affinity chromatography, nanoflow liquid chromatography, and high accuracy mass spectrometry, six peptides, SPFPR(L/I)amide, APFPR( L/I)amide, SPLPR( L/I)amide, SFVR( L/I)amide, AFVR( L/I)amide, and SPAFVR( L/I)amide, were identified in the central nervous system with the common-XR( L/I)amide C-terminal sequence. The exact anatomical position of 13 labeled XR( I/L)amide expressing neuron groups and numerous peptide-containing fibers were determined by means of immunocytochemistry and confocal laser scanning microscopy in whole-mount preparations of ventral nerve cord ganglia. The majority of the stained neurons were interneurons with processes joining the distinct fine-fibered polysegmental tracts in the central neuropil. Some stained fibers were seen running in each segmental nerve that innervated metanephridia and body wall. Distinct groups of neurosecretory cells characterized by small round soma and short processes were also identified. Based on immunoelectron microscopy six different types of labeled cells were described showing morphological heterogeneity of earthworm peptides containing elements. Our findings confirm that the sequence of the identified earthworm neuropeptides homologous to the insect PVKs and PKs suggesting that these peptides are phylogenetically conservative molecules and are expressed in sister-groups of animals such as annelids, mollusks, and insects. J. Comp. Neurol. 514:415-432, 2009. (c) 2009 Wiley-Liss, Inc.

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    • "Most of the neuropeptides, like proctolin, FMRFamide-like peptides, neuropeptide Y (Lengvari et al., 2001), substance P and ACTH-like peptide (Aros et al., 1980), believed to be regulator molecules in earthworms had only been identified by immunocytochemical stainings. There are only a few neuropeptides, e.g., CAPA-peptides (Herbert et al., 2009) and pituitary adenylate cyclase activating polypeptide (PACAP)-like peptides (Somogyvári- Vígh et al., 2000) which expression, pattern and function have investigated by various experimental protocols in details. PACAP is a highly conserved member of the VIP/secretin/glucagon peptide family found in neuronal elements of both the CNS and several peripheral tissues of vertebrates. "

    Invertebrate Survival Journal 01/2015; 12:173-175. · 0.93 Impact Factor
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    • "The unpurified antiserum recognizes peptides with the C-terminal sequence PRXamide and is known to react with periviscerokinins and with pyrokinins (Eckert et al., 2002). It has been used to specifically label these substances in a variety of insect species (D. melanogaster: Wegener et al., 2004; Nezara viridula: Predel et al., 2006; Manduca sexta: Neupert et al., 2009); Schistocerca gregaria: Herbert et al., 2010; Acyrthosiphon pisum: Kollmann et al., 2011a), in the chelicerate Ixodes ricinus (Neupert et al., 2005), and in the clitellate annelid Eisenia fetida (Herbert et al., 2009). "
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    ABSTRACT: Neuropeptides are a highly diverse group of signaling molecules that affect a broad range of biological processes in insects, including development, metabolism, behavior, and reproduction. In the central nervous system, neuropeptides are usually considered to act as neuromodulators and co-transmitters that modify the effect of 'classical' transmitters at the synapse. The present study analyzes the neuropeptide repertoire of higher cerebral neuropils in the brain of the red flour beetle Tribolium castaneum. We focus on two integrative neuropils of the olfactory pathway, the antennal lobes and the mushroom bodies. Using the technique of direct peptide profiling by MALDI-TOF mass spectrometry, we demonstrate that these neuropils can be characterized by their specific neuropeptide expression profiles. Complementary immunohistological analyses of selected neuropeptides revealed neuropeptide distribution patterns within the antennal lobes and the mushroom bodies. Both approaches revealed consistent differences between the neuropils, underlining that direct peptide profiling by mass spectrometry is a fast and reliable method to identify neuropeptide content. J. Comp. Neurol., 2013. © 2013 Wiley Periodicals, Inc.
    The Journal of Comparative Neurology 02/2014; 522(2). DOI:10.1002/cne.23399 · 3.23 Impact Factor
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    • "Annelids represent a diverse and species-rich phylum and have long been used in neuroendocrinological and behavioral studies [39]. Comparative genomic approaches [19,20,40] and other studies identified multiple annelid pNPs and neuropeptides, including RFa [13,41-47], FVRIa [48-50], excitatory peptide (EP) [51-53], egg-laying hormone (ELH) [54], myomodulin [55-57], RGWa [13], L11 or elevenin [28], vasopressin [39,58,59], gonadotropin releasing hormone (GnRH) [60,61], insulin-related peptides [62], neuropeptide Y (NPY) [63,64] and myoinhibitory peptide (MIP) [65]. Despite these advances, a complete picture of annelid neuropeptide diversity is still missing. "
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