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- Dircksen, Heinrich, 1954-, et al.
(author)
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Genomics, transcriptomics and peptidomics of Daphnia pulex neuropeptides and protein hormones
- 2011
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In: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 10:10, s. 4478-4504
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Journal article (peer-reviewed)abstract
- We report 43 novel genes in the water flea Daphnia pulex encoding 73 predicted neuropeptide and protein hormones as partly confirmed by RT-PCR. MALDI-TOF mass spectrometry identified 40 neuropeptides by mass matches and 30 neuropeptides by fragmentation sequencing. Single genes encode adipokinetic hormone, allatostatin-A, allatostatin-B, a first crustacean allatotropin, Ala7-CCAP, one CCHamide, Arg7-corazonin, CRF-like (DH52) and calcitonin-like (DH31) diuretic hormones, two ecdysis-triggering hormones, two FIRFamides, one insulin- and one each of three IGF-related peptides, two alternative splice forms of short and long ion transport peptide (ITP), one each of two N-terminally elongated ITPs, myosuppressin, neuroparsin, two neuropeptide-F splice forms, three periviscerokinins (but no pyrokinins), pigment dispersing hormone, proctolin, Met4-proctolin, one novel short neuropeptide-F, three RYamides, SIFamide, two sulfakinins, three tachykinins. Two genes encode orcokinins, three genes different allatostatins-C. Paired gene clusters occur for two novel eclosion hormones; bursicons alpha, beta; glycoproteins GPA2, GPB5; and two of the allatostatin-C genes. Detailed comparisons of genes or their products with those from insects and decapod crustaceans revealed that the D. pulex peptides are often closer to their insect than to their decapod crustacean homologues, confirming that branchiopods, to which Daphnia belongs, are the ancestor group of insects.
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| 2. |
- Strauss, Johannes, et al.
(author)
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Pigment-dispersing hormone in Daphnia interneurons, one type homologous to insect clock neurons displaying circadian rhythmicity
- 2011
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In: Cellular and Molecular Life Sciences (CMLS). - : Springer Science and Business Media LLC. - 1420-682X .- 1420-9071. ; 68:20, s. 3403-3423
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Journal article (peer-reviewed)abstract
- We report identification of a beta-type pig-ment-dispersing hormone (PDH) identical in two water fleaspecies, Daphnia magna and Daphnia pulex. It has been identified by cloning of precursors, chromatographic iso-lation from tissue extracts followed by immunoassays and de novo-mass spectrometric sequencing. The peptide is restricted to a complex system of distinct interneurons in the brain and visual ganglia, but does not occur in neurosecretory cells projecting to neurohemal organs as in decapod crustaceans. Thirteen neuron types individually identified and reconstructed by immunohistochemistry were almost identical in terms of positions and projection patterns in both species. Several neurons invade and form plexuses in visual ganglia and major brain neuropils including the central body. Five neuron types show con-tralateral pathways and form plexuses in the lateral, dorsal,or postlateral brain neuropils. Others are local interneurons,and a tritocerebral neuron connects the protocerebrum with the neuropil of the locomotory second antenna. Two visual ganglia neuron types lateral to the medulla closely resemble insect medulla lateral circadian clock neurons containing pigment-dispersing factor based upon positional and projectional criteria. Experiments under 12:12 h light/dark cycles and constant light or darkness conditions showed significant circadian changes in numbers and activities of one type of medulla lateral PDH neuron with an acrophase in the evening. This simple PDH system shows striking homologies to PDH systems in decapod crustaceans and well-known clock neurons in several insects, which suggests evolutionary conservation of an ancient peptidergic interneuronal system that is part of biological clocks.
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