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  • 1. Altstein, Miriam
    et al.
    Nässel, Dick R
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Neuropeptide signaling in insects.2010Inngår i: Neuropeptide systems as targets for parasite and pest control / [ed] Timothy G. Geary and Aaron G. Maule, New York: Springer Science+Business Media , 2010, Vol. 692, s. 155-65Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Neuropeptides represent the largest single class of signal compounds and are involved in regulation of development, growth, reproduction, metabolism and behavior of insects. Over the last few years there has been a tremendous increase in our knowledge of neuropeptide signaling due to genome sequencing, peptidomics, gene micro arrays, receptor characterization and targeted gene interference combined with physiological and behavior analysis. In this chapter we review the current knowledge of structure and distribution of insect neuropeptides and their receptors, as well as their diverse functions. We also discuss peptide biosynthesis, processing and expression, as well as classification of insect neuropeptides. Special attention is paid to the role insect neuropeptides play as potential targets for pest management and as a basis for development of insect control agents employing the rational/structural design approaches.

  • 2.
    Antonopoulou, Efthimia
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Feedback control of reproduction in Atlantic salmon, Salmo salar, male parr1998Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In fish, as in other vertebrates, the gonads are stimulated by two pituitary gonadotropic hormones, follicle stimulating hormone (FSH) and luteinizing hormone (LH). LH and FSH secretion are regulated by the gonadal steroids acting either directly on the pituitary or indirectly via the hypothalamus. Both positive and negative gonadal feedback mechanisms are present in fishes. Plasma and pituitary LH and FSH levels are higher in Atlantic salmon parr males that have been sham-operated in spring than in castrated fish, when sampled in the periods of gonadal growth and breeding, indicated the existence of a physiological positive feedback involved in the control of LH and FSH secretion. However, for FSH also a physiological negative feedback controlling FSH secretion was found in the early phase of sexual maturation in early summer.

    The involvement of different steroids and the role of aromatization in feedback systems controlling reproduction has also been studied by administration of different androgens and aromatase inhibitors in vivo. Testosterone (T) stimulates LH by an aromatase-dependent positive feedback. Also 11-androgens exert a positive effect on LH, though weaker than T. FSH appears to be controlled both by a negative aromatase dependent feedback and a negative non-aromatase dependent T effect, as well as possibly a positive aromatase-dependent feedback. FSH is also controlled by both a negative and a positive feedback of 11-androgens. In addition, treatment with different aromatase inhibitors increased the proportion of fish maturing.

    Positive gonadal feedback eventually separate gonadotropic functions between rematuring high level and non-rematuring low level fish. However, FSH secretion appears not to be the only responsible factor for the onset of maturation in Atlantic salmon male parr, since immunoassayable plasma FSH levels are equally high in non-rematuring and rematuring fish during the onset of gonadal growth in early summer.

    The decline of androgens at the beginning of breeding season is not due to a suppressive action of elevated 17,20P at either the pituitary or testicular level in salmon.

    Moreover, administration of T at the end of spawning season diminished the postbreeding decline of 17,20P, testes weights, milt production and sperm motility, possibly via a positive feedback on LH secretion.

  • 3.
    Birse, Ryan T.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Söderberg, Jeannette A. E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Luo, Jiangnan
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Winther, Åsa M. E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Nässel, Dick R.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Regulation of insulin-producing cells in the adult Drosophila brain via the tachykinin peptide receptor DTKR2011Inngår i: Journal of Experimental Biology, ISSN 0022-0949, E-ISSN 1477-9145, Vol. 214, s. 4201-4208Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Drosophila insulin-like peptides (DILPs) play important hormonal roles in the regulation of metabolic carbohydrates and lipids, but also in reproduction, growth, stress resistance and aging. In spite of intense studies of insulin signaling in Drosophilag the regulation of DILP production and release in adult fruit flies is poorly understood. Here we investigated the role of Drosophila tachykinin-related peptides (DTKs) and their receptors, DTKR and NKD, in the regulation of brain insulin-producing cells (IPCs) and aspects of DILP signaling. First, we show DTK-immunoreactive axon terminations close to the presumed dendrites of the IPCs, and DTKR immunolabeling in these cells. Second, we utilized targeted RNA interference to knock down expression of the DTK receptor, DTKR, in IPCs and monitored the effects on Dilp transcript levels in the brains of fed and starved flies. Dilp2 and Dilp3, but not Dilp5, transcripts were significantly affected by DTKR knockdown in IPCs, both in fed and starved flies. Both Dilp2 and Dilp3 transcripts increased in fed flies with DTKR diminished in IPCs whereas at starvation the Dilp3 transcript plummeted and Dilp2 increased. We also measured trehalose and lipid levels as well as survival in transgene flies at starvation. Knockdown of DTKR in IPCs leads to increased lifespan and a faster decrease of trehalose at starvation but has no significant effect on lipid levels. Finally, we targeted the IPCs with RNAi or ectopic expression of the other DTK receptor, NKD, but found no effect on survival at starvation. Our results suggest that DTK signaling, via DTKR, regulates the brain IPCs.

  • 4.
    Borg, Bertil
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Photoperiodism in Fishes2010Inngår i: Photoperiodism: the Biological Calender / [ed] Randy J. Nelson, David L. Denlinger and David E. Somers, New York, New York, USA: Oxford University Press , 2010, 1, s. 371-398Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 5.
    Breidbach, Olaf
    et al.
    Institute of Applied Zoology, University of Bonn, Germany.
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Proctolin-immunoreactive neurons persist during metamorphosis of an insect: A developmental study of the ventral nerve cord of Tenebrio molitor(Coleoptera)1989Inngår i: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 257, nr 1, s. 217-225Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Proctolin-immunoreactive neurons in all neuromers of the ventral nerve cord of Tenebrio molitor L. have been quantitatively demonstrated and mapped throughout metamorphosis. Each neuromer contains an anterior and a posterior group of neurons with light and dark staining properties as revealed by peroxidase-antiperoxidase labeling. Serial homologous subsets of dark staining neurons with central and peripheral projections have been identified and found to persist during morphogenetic changes from the larva to the adult. Most neurons maintain their topological and structural characteristics throughout metamorphosis. The identified proctolin-immunoreactive neurons exhibit structures similar to those described in other insect species; some may correspond known motoneurons.

  • 6. Campos, Bruno
    et al.
    Rivetti, Claudia
    Kress, Timm
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Barata, Carlos
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Depressing antidepressant: Fluoxetine affects serotonin neurons causing adverse reproductive responses in Daphnia magna2016Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, nr 11, s. 6000-6007Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Selective serotonin reuptake inhibitors (SSRIs) are widely used antidepressants. As endocrine disruptive contaminants in the environment, SSRIs affect reproduction in aquatic organisms. In the water flea Daphnia magna, SSRIs increase offspring production in a food ration-dependent manner. At limiting food conditions, females exposed to SSRIs produce more but smaller offspring, which is a maladaptive life-history strategy. We asked whether increased serotonin levels in newly identified serotonin-neurons in the Daphnia brain mediate these effects. We provide strong evidence that exogenous SSRI fluoxetine selectively increases serotonin-immunoreactivity in identified brain neurons under limiting food conditions thereby leading to maladaptive offspring production. Fluoxetine increases serotonin-immunoreactivity at low food conditions to similar maximal levels as observed under high food conditions and concomitantly enhances offspring production. Sublethal amounts of the neurotoxin 5,7-dihydroxytryptamine known to specifically ablate serotonin-neurons markedly decrease serotonin-immunoreactivity and offspring production, strongly supporting the effect to be serotonin-specific by reversing the reproductive phenotype attained under fluoxetine. Thus, SSRIs impair serotonin-regulation of reproductive investment in a planktonic key organism causing inappropriately increased reproduction with potentially severe ecological impact.

  • 7.
    Carlsson, Mikael A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Diesner, Max
    Philipps University, Marburg.
    Schachtner, Joachim
    Philipps University, Marburg.
    Nässel, Dick R.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Multiple neuropeptides in the Drosophila antennal lobe suggest complex modulatory circuits2010Inngår i: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 518, nr 16, s. 3359-3380Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The fruitfly, Drosophila, is dependent on its olfactory sense in food search and reproduction. Processing of odorant information takes place in the antennal lobes, the primary olfactory center in the insect brain. Besides classical neurotransmitters, earlier studies have indicated the presence of a few neuropeptides in the olfactory system. In the present study we made an extensive analysis of the expression of neuropeptides in the Drosophila antennal lobes by direct profiling using matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry and immunocytochemistry. Neuropeptides from seven different precursor genes were unambiguously identified and their localization in neurons was subsequently revealed by immunocytochemistry. These were short neuropeptide F, tachykinin related peptide, allatostatin A, myoinhibitory peptide, SIFamide, IPNamide, and myosuppressin. The neuropeptides were expressed in subsets of olfactory sensory cells and different populations of local interneurons and extrinsic (centrifugal) neurons. In some neuron types neuropeptides were colocalized with classical neurotransmitters. Our findings suggest a huge complexity in peptidergic signaling in different circuits of the antennal lobe.

  • 8. Chung, J. Sook
    et al.
    Katayama, Hidekazu
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    New Functions of Arthropod Bursicon: Inducing Deposition and Thickening of New Cuticle and Hemocyte Granulation in the Blue Crab, Callinectes sapidus2012Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, nr 9, s. e46299-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Arthropod growth requires molt-associated changes in softness and stiffness of the cuticle that protects from desiccation, infection and injury. Cuticle hardening in insects depends on the blood-borne hormone, bursicon (Burs), although it has never been determined in hemolymph. Whilst also having Burs, decapod crustaceans reiterate molting many more times during their longer life span and are encased in a calcified exoskeleton, which after molting undergoes similar initial cuticle hardening processes as in insects. We investigated the role of homologous crustacean Burs in cuticular changes and growth in the blue crab, Callinectes sapidus. We found dramatic increases in size and number of Burs cells during development in paired thoracic ganglion complex (TGC) neurons with pericardial organs (POs) as neurohemal release sites. A skewed expression of Burs β/Burs α mRNA in TGC corresponds to protein contents of identified Burs β homodimer and Burs heterodimer in POs. In hemolymph, Burs is consistently present at ~21 pM throughout the molt cycle, showing a peak of ~89 pM at ecdysis. Since initial cuticle hardness determines the degree of molt-associated somatic increment (MSI), we applied recombinant Burs in vitro to cuticle explants of late premolt or early ecdysis. Burs stimulates cuticle thickening and granulation of hemocytes. These findings demonstrate novel cuticle-associated functions of Burs during molting, while the unambiguous and constant presence of Burs in cells and hemolymph throughout the molt cycle and life stages may implicate further functions of its homo- and heterodimer hormone isoforms in immunoprotective defense systems of arthropods.

  • 9. Derst, Christian
    et al.
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Meusemann, Karen
    Zhou, Xin
    Liu, Shanlin
    Predel, Reinhard
    Evolution of neuropeptides in non-pterygote hexapods2016Inngår i: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 16, artikkel-id 51Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background

    Neuropeptides are key players in information transfer and act as important regulators of development, growth, metabolism, and reproduction within multi-cellular animal organisms (Metazoa). These short protein-like substances show a high degree of structural variability and are recognized as the most diverse group of messenger molecules. We used transcriptome sequences from the 1KITE (1K Insect Transcriptome Evolution) project to search for neuropeptide coding sequences in 24 species from the non-pterygote hexapod lineages Protura (coneheads), Collembola (springtails), Diplura (two-pronged bristletails), Archaeognatha (jumping bristletails), and Zygentoma (silverfish and firebrats), which are often referred to as “basal” hexapods. Phylogenetically, Protura, Collembola, Diplura, and Archaeognatha are currently placed between Remipedia and Pterygota (winged insects); Zygentoma is the sistergroup of Pterygota. The Remipedia are assumed to be among the closest relatives of all hexapods and belong to the crustaceans.

    Results

    We identified neuropeptide precursor sequences within whole-body transcriptome data from these five hexapod groups and complemented this dataset with homologous sequences from three crustaceans (including Daphnia pulex), three myriapods, and the fruit fly Drosophila melanogaster. Our results indicate that the reported loss of several neuropeptide genes in a number of winged insects, particularly holometabolous insects, is a trend that has occurred within Pterygota. The neuropeptide precursor sequences of the non-pterygote hexapods show numerous amino acid substitutions, gene duplications, variants following alternative splicing, and numbers of paracopies. Nevertheless, most of these features fall within the range of variation known from pterygote insects. However, the capa/pyrokinin genes of non-pterygote hexapods provide an interesting example of rapid evolution, including duplication of a neuropeptide gene encoding different ligands.

    Conclusions

    Our findings delineate a basic pattern of neuropeptide sequences that existed before lineage-specific developments occurred during the evolution of pterygote insects.

  • 10.
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Conserved crustacean cardioactive peptide neural networks and functions in arthropod evolution1998Inngår i: Recent Advances in Arthropod Endocrinology / [ed] Geoffrey M. Coast, Simon G. Webster, Cambridge: Cambridge University Press, 1998, 65, s. 302-333Kapittel i bok, del av antologi (Fagfellevurdert)
  • 11.
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Crustacean bioactive peptides2013Inngår i: Handbook of Biologically Active Peptides / [ed] Abba J. Kastin, New York: Academic Press Elsevier , 2013, 2, s. 209-221Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Research on crustacean peptides has concentrated mainly on decapods and isopods, and a growing number of >200 peptides have been sequenced from these two groups, the majority from decapods, but recently, the annotation of the Daphnia pulexgenome has contributed many more novel peptides many of which were also sequenced de novo. Identified and bioactive crustacean peptides — the only ones reported here — regulate a large range of physiological functions, including color change, activities of heart, exoskeletal and visceral muscles, metabolic function, development, metamorphosis, and reproduction.

  • 12.
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Insect ion transport peptides are derived from alternatively spliced genes and differentially expressed in the central and peripheral nervous system.2009Inngår i: Journal of Experimental Biology, ISSN 0022-0949, E-ISSN 1477-9145, Vol. 212, nr Pt 3, s. 401-12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Insect ionic and fluid homeostasis relies upon the Malpighian tubules (MT) and different hindgut compartments. Primary urine formed in MTs is finally modified by ion, solute and water reabsorptive processes primarily in the hindgut under the control of several large peptide hormones. One of these, the ion transport peptide (ITP), is a chloride transport-stimulating and acid secretion-inhibiting hormone similar to crustacean hyperglycaemic hormones (CHHs). In locusts, moths and fruit flies, ITP together with the slightly longer ITPL isoforms, inactive in hindgut bioassays, arise by alternative splicing from very similar itp genes. ITP and ITPL are differentially distributed in (1) pars lateralis/retrocerebral complex neurosecretory cells (NSCs) containing both splice forms, (2) interneurons with either one of the splice forms, (3) hindgut-innervating abdominal ITP neurons (in Drosophila only), and (4) intrinsic, putative sensory NSCs in peripheral neurohaemal perisympathetic/perivisceral organs or transverse nerves (usually containing ITPL). Both splice forms occur as hormones released into the haemolymph in response to feeding or stress stimuli. ITPL mainly released from the peripheral NSCs is discussed as a competitive inhibitor (as established in vitro) of ITP action on yet to be identified hindgut ITP receptors. Furthermore, some evidence has been provided for possible ecdysis-related functions of ITP and/or ITPL in moths. The comparative data on the highly similar gene, precursor and primary structures and similar differential distributions in insect and crustacean NSCs suggest that CHH/ITP and ITPL neuropeptide-producing cells and their gene products share common phylogenetic ancestry.

  • 13.
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Neurosecretory endings in the pericardial organs of the shore crab Carcinus maenas L., and their identification by neuropeptide immunocytochemistry1991Inngår i: Comparative aspects of neuropeptide function. / [ed] Ernst Florey, George B. Stefano, Manchester, New York: Manchester University Press, 1991, s. 198-200Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 14.
    Dircksen, Heinrich
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Mandali, Aditya
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Yoshii, Taishi
    Strauss, Johannes
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Helfrich-Foerster, Charlotte
    Nässel, Dick R
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Differential neuronal expression of three Drosophila ion transport peptide splice forms indicate multiple functions of peptidergic neurons2009Inngår i: Comparative Biochemistry and Physiology A, ISSN 1095-6433, E-ISSN 1531-4332, Vol. 153A, nr 2, suppl. 1, s. S79-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We identified previously two long (DrmITPL1 and -L2) and one amidated short isoform (DrmITP) of insect ion transport peptides (ITPs) as products derived by alternatively splicing from the Drosophila itp-gene (CG13586). The peptides are members of a large family of arthropod neuropeptides incl. crustacean hyperglycemic hormones (CHH/ITP-family), but similar ITPs are only known in locusts to have antidiuretic bioactivity on the hindgut. We localised the peptides by in situ hybridisation and immunocytochemistry with isoform-specific antibodies in the nervous system of larval (L3) and adult Drosophila melanogaster and screened Gal4-lines specific for peptidergic cells. Four neurosecretory cells in brain-corpora cardiaca/allata putatively release DrmITP as a hormone in all stages. DrmITP also occurs in interneurons in the brain/ventral ganglia and in neurons efferent towards the hindgut. Some interneurons are identical to well-known circadian clock neurons for which the effector molecules were elusive but are responsible for the evening bouts of locomotor activity in flies. DrmITPL1 and -L2 were found only in peripheral lateral bipolar and putative sensory neurons which are likely to play a role in the control of growth, hindgut ion transport and heart beat. With DrmITP identified in brain neurosecretory cells, hindgut-innervating neurons in the abdominal ganglia and one pair in the abdomen close to the larval anal organ or innervating the adult rectal pads, both chloride-transporting organs, we are facing an enormous complexity in multiple functions of differentially expressed ITP/Ls derived from a single gene. Preliminary results using Gal4-driven RNAi in distinct peptidergic neurons look promising to find deficiency phenotypes.

  • 15.
    Dircksen, Heinrich
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Müller, Arno
    Keller, Rainer
    Crustacean cardioactive peptide in the nervous system of the locust, Locusta migratoria: an immunocytochemical study on the ventral nerve cord and peripheral innervation1991Inngår i: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 263, s. 439-457Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Crustacean cardioactive peptide-immunoreactive neurons occur in the entire central nervous system of Locusta migratoria. The present paper focuses on mapping studies in the ventral nerve cord and on peripheral projection sites. Two types of contralaterally projecting neurons occur in all neuromers from the subesophageal to the seventh abdominal ganglia. One type forms terminals at the surface of the thoracic nerves 6 and 1, the distal perisympathetic organs, the lateral heart nerves, and on ventral and dorsal diaphragm muscles. Two large neurons in the anterior part and several neurons of a different type in the posterior part of the terminal ganglion project into the last tergal nerves. In the abdominal neuromers 1–7, two types of ipsilaterally projecting neurons occur, one of which gives rise to neurosecretory terminals in the distal perisympathetic organs, in peripheral areas of the transverse, stigmata and lateral heart nerves. Four subesophageal neurons have putative terminals in the neurilemma of the nervus corporis allati II, and in the corpora allata and cardiaca. In addition, several immunoreactive putative interneurons and other neurons were mapped in the ventral nerve cord. A new in situ whole-mount technique was essential for elucidation of the peripheral pathways and targets of the identified neurons, which suggest a role of the peptide in the control of heartbeat, abdominal ventilatory and visceral muscle activity.

  • 16.
    Dircksen, Heinrich
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Neupert, Susanne
    Predel, Reinhard
    Verleyen, Peter
    Huybrechts, Jurgen
    Strauss, Johannes
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Hauser, Frank
    Stafflinger, Elisabeth
    Schneider, Martina
    Pauwels, Kevin
    Schoofs, Liliane
    Grimmelikhuijzen, Cornelis J. P.
    Genomics, transcriptomics and peptidomics of Daphnia pulex neuropeptides and protein hormones2011Inngår i: Journal of Proteome Research, ISSN 1535-3893, E-ISSN 1535-3907, Vol. 10, nr 10, s. 4478-4504Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 17.
    Dircksen, Heinrich
    et al.
    Institute of Zoophysiology, University of Bonn, Germany.
    Skiebe, Petra
    Freie Universität Berlin.
    Abel, Britta
    University of Bonn.
    Agricola, Hans
    University of Jena.
    Buchner, Klaus
    Freie Universität Berlin.
    Muren, J. Eric
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Nässel, Dick
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Structure, distribution, and biological activity of novel members of the allatostatin family in the crayfish Orconectes limosus.1999Inngår i: Peptides, ISSN 0196-9781, E-ISSN 1873-5169, Vol. 20, nr 6, s. 695-712Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the central and peripheral nervous system of the crayfish, Orconectes limosus, neuropeptides immunoreactive to an antiserum against allatostatin I (= Dipstatin 7) of the cockroach Diploptera punctata have been detected by immunocytochemistry and a sensitive enzyme immunoassay. Abundant immunoreactivity occurs throughout the central nervous system in distinct interneurons and neurosecretory cells. The latter have terminals in well-known neurohemal organs, such as the sinus gland, the pericardial organs, and the perineural sheath of the ventral nerve cord. Nervous tissue extracts were separated by reverse-phase high-performance liquid chromatography and fractions were monitored in the enzyme immunoassay. Three of several immunopositive fractions have been purified and identified by mass spectroscopy and microsequencing as AGPYAFGL-NH2, SAGPYAFGL-NH2, and PRVYGFGL-NH2. The first peptide is identical to carcinustatin 8 previously identified in the crab Carcinus maenas. The others are novel and are designated orcostatin I and orcostatin II, respectively. All three peptides exert dramatic inhibitory effects on contractions of the crayfish hindgut. Carcinustatin 8 also inhibits induced contractions of the cockroach hindgut. Furthermore, this peptide reduces the cycle frequency of the pyloric rhythms generated by the stomatogastric nervous system of two decapod species in vitro. These crayfish allatostatin-like peptides are the first native crustacean peptides with demonstrated inhibitory actions on hindgut muscles and the pyloric rhythm of the stomatogastric ganglion.

  • 18.
    Dircksen, Heinrich
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Tesfai, Lily Kahsai
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Albus, Christina
    Nässel, Dick R
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Ion transport peptide splice forms in central and peripheral neurons throughout postembryogenesis of Drosophila melanogaster.2008Inngår i: The Journal of comparative neurology, ISSN 1096-9861, Vol. 509, nr 1, s. 23-41Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ion transport peptides (ITPs) belong to a large arthropod neuropeptide family including crustacean hyperglycaemic hormones and are antidiuretic hormones in locusts. Because long and short ITP isoforms are generated by alternative splicing from a single gene in locusts and moths, we investigated whether similarly spliced gene products occur in the nervous system of Drosophila melanogaster throughout postembryogenesis. The itp gene CG13586 was reanalyzed, and we found three instead of the two previously annotated alternatively spliced mRNAs. These give rise to three different neuropeptides, two long C-terminally carboxylated isoforms (DrmITPL1 and DrmITPL2, both 87 amino acids) and one short amidated DrmITP (73 amino acids), which were partially identified biochemically. Immunocytochemistry and in situ hybridization reveal nine larval and 14 adult identified neurons: four pars lateralis neurosecretory neurons, three hindgut-innervating neurons in abdominal ganglia, and a stage-specific number of interneurons and peripheral bipolar neurons. The neurosecretory neurons persist throughout postembryogenesis, form release sites in corpora cardiaca, and invade corpora allata. One type of ITP-expressing interneuron exists only in the larval and prepupal subesophageal ganglia, whereas three types of interneurons in the adult brain arise in late pupae and invade circumscribed neuropils in superior median and lateral brain areas. One peripheral bipolar and putative sensory neuron type occurs in the larval, pupal, and adult preterminal abdominal segments. Although the neurosecretory neurons may release DrmITP and DrmITPL2 into the haemolymph, possible physiological roles of the hindgut-innervating and peripheral neurons as well as the interneurons are yet to be identified.

  • 19.
    Dircksen, Heinrich
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi. Rheinische Friedrich-Wilhelms Universität, Germany.
    Webster, Simon G.
    School of Biological Sciences University of Wales, Bangor, UK.
    Keller, Rainer
    Immunocytochemical demonstration of the neurosecretory systems containing putative moult-inhibiting hormone and hyperglycemic hormone in the eyestalk of brachyuran crustaceans1988Inngår i: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 251, s. 3-12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    By use of antisera raised against purified moultinhibiting (MIH) and crustacean hyperglycemic hormone (CHH) from Carcinus maenas, complete and distinct neurosecretory pathways for both hormones were demonstrated with the PAP and immunofluorescence technique. By double staining, employing a combination of silver-enhanced immunogold labelling and PAP, both antigens could be visualized in the same section. Immunoreactive structures were studied in Carcinus maenas, Liocarcinus puber, Cancer pagurus, Uca pugilator and Maja squinado. They were only observed in the X-organ sinus gland (SG) system of the eyestalks and consisted of MIH-positive perikarya, which were dispersed among the more numerous CHH-positive perikarya of the medulla terminalis X-organ (XO). The MIH-positive neurons form branching collateral plexuses adjacent to the XO and axons that are arranged around the CHH-positive central axon bundle of the principal XO-SG tract. In the SG, MIH-positive axon profiles and terminals, clustered around hemolymph lacunae, are distributed between the more abundant CHH-positive axon profiles and terminals. Colocalisation of MIH and CHH was never observed. The gross morphology of both neurosecretory systems was similar in all species examined, however, in U. pugilator and M. squinado immunostaining for MIH was relatively faint unless higher concentrations of antiserum were used. Possible reasons for this phenomenon as well as observed moult cycle-related differences in immunostaining are discussed.

  • 20.
    Dircksen, Heinrich
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Wilcockson, Dave C
    Webster, Simon G
    Neuropeptides in a forgotten crustacean neurohaemal organ classic, the postcomissural organs of the shrimp Palaemon serratus2005Inngår i: Comparative Biochemistry and Physiology A, ISSN 1095-6433, E-ISSN 1531-4332, Vol. 141, nr 3, s. S156-S157Artikkel i tidsskrift (Fagfellevurdert)
  • 21.
    Enell, Lina E.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Kapan, Neval
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Söderberg, Jeannette A.E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Kahsai, Lily
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Nässel, Dick R.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Insulin Signaling, Lifespan and Stress Resistance Are Modulated by Metabotropic GABA Receptors on Insulin Producing Cells in the Brain of Drosophila2010Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 5, nr 12, s. e15780-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Insulin-like peptides (ILPs) regulate growth, reproduction, metabolic homeostasis, life span and stress resistance in worms, flies and mammals. A set of insulin producing cells (IPCs) in the Drosophila brain that express three ILPs (DILP2, 3 and 5) have been the main focus of interest in hormonal DILP signaling. Little is, however, known about factors that regulate DILP production and release by these IPCs. Here we show that the IPCs express the metabotropic GABA(B) receptor (GBR), but not the ionotropic GABA(A) receptor subunit RDL. Diminishing the GBR expression on these cells by targeted RNA interference abbreviates life span, decreases metabolic stress resistance and alters carbohydrate and lipid metabolism at stress, but not growth in Drosophila. A direct effect of diminishing GBR on IPCs is an increase in DILP immunofluorescence in these cells, an effect that is accentuated at starvation. Knockdown of irk3, possibly part of a G protein-activated inwardly rectifying K(+) channel that may link to GBRs, phenocopies GBR knockdown in starvation experiments. Our experiments suggest that the GBR is involved in inhibitory control of DILP production and release in adult flies at metabolic stress and that this receptor mediates a GABA signal from brain interneurons that may convey nutritional signals. This is the first demonstration of a neurotransmitter that inhibits insulin signaling in its regulation of metabolism, stress and life span in an invertebrate brain.

  • 22.
    Enell, Lina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Hamasaka, Yasutaka
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Kolodziejczyk, Agata
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Nässel, Dick R
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    gamma-Aminobutyric acid (GABA) signaling components in Drosophila: immunocytochemical localization of GABA(B) receptors in relation to the GABA(A) receptor subunit RDL and a vesicular GABA transporter.2007Inngår i: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 505, nr 1, s. 18-31Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter in insects and is widely distributed in the central nervous system (CNS). GABA acts on ion channel receptors (GABAAR) for fast inhibitory transmission and on G-protein-coupled ones (GABABR) for slow and modulatory action. We used immunocytochemistry to map GABABR sites in the Drosophila CNS and compared the distribution with that of the GABAAR subunit RDL. To identify GABAergic synapses, we raised an antiserum to the vesicular GABA transporter (vGAT). For general GABA distribution, we utilized an antiserum to glutamic acid decarboxylase (GAD1) and a gad1-GAL4 to drive green fluorescent protein. GABABR-immunoreactive (IR) punctates were seen in specific patterns in all major neuropils of the brain. Most abundant labeling was seen in the mushroom body calyces, ellipsoid body, optic lobe neuropils, and antennal lobes. The RDL distribution is very similar to that of GABABR-IR punctates. However, the mushroom body lobes displayed RDL-IR but not GABABR-IR material, and there were subtle differences in other areas. The vGAT antiserum labeled punctates in the same areas as the GABABR and appeared to display presynaptic sites of GABAergic neurons. Various GAL4 drivers were used to analyze the relation between GABABR distribution and identified neurons in adults and larvae. Our findings suggest that slow GABA transmission is very widespread in the Drosophila CNS and that fast RDL-mediated transmission generally occurs at the same sites. J. Comp. Neurol. 505:18–31, 2007.

  • 23.
    Gáliková, Martina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Nässel, Dick R.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    The thirsty fly: Ion transport peptide (ITP) is a novel endocrine regulator of water homeostasis in Drosophila2018Inngår i: PLOS Genetics, ISSN 1553-7390, E-ISSN 1553-7404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Animals need to continuously adjust their water metabolism to the internal and external conditions. Homeostasis of body fluids thus requires tight regulation of water intake and excretion, and a balance between ingestion of water and solid food. Here, we investigated how these processes are coordinated in Drosophila melanogaster. We identified the first thirst-promoting and anti-diuretic hormone of Drosophila, encoded by the gene Ion transport peptide (ITP). This endocrine regulator belongs to the CHH (crustacean hyperglycemic hormone) family of peptide hormones. Using genetic gain- and loss-of-function experiments, we show that ITP signaling acts analogous to the human vasopressin and renin-angiotensin systems; expression of ITP is elevated by dehydration of the fly, and the peptide increases thirst while repressing excretion, promoting thus conservation of water resources. ITP responds to both osmotic and desiccation stress, and dysregulation of ITP signaling compromises the fly’s ability to cope with these stressors. In addition to the regulation of thirst and excretion, ITP also suppresses food intake. Altogether, our work identifies ITP as an important endocrine regulator of thirst and excretion, which integrates water homeostasis with feeding of Drosophila.

  • 24.
    Helle, Johannes
    et al.
    Universität Göttingen.
    Dircksen, Heinrich
    Institute of Zoophysiology, University of Bonn, Germany.
    Eckert, Manfred
    Friedrich-Schiller-Universität, Jena.
    Nässel, Dick
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Spörhase-Eichmann, Ulrike
    Universität Göttingen.
    Schürmann, Friedrich-Wilhelm
    Putative neurohemal areas in the peripheral nervous system of an insect, Gryllus bimaculatus, revealed by immunocytochemistry.1995Inngår i: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 281, nr 1, s. 43-61Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The morphology and position of putative neurohemal areas in the peripheral nervous system (ventral nerve cord and retrocerebral complex) of the cricket Gryllus bimaculatus are described. By using antisera to the amines dopamine, histamine, octopamine, and serotonin, and the neuropeptides crustacean cardioactive peptide, FMRFamide, leucokinin 1, and proctolin, an extensive system of varicose fibers has been detected throughout the nerves of all neuromeres, except for nerve 2 of the prothoracic ganglion. Immunoreactive varicose fibers occur mainly in a superficial position at the neurilemma, indicating neurosecretory storage and release of neuroactive compounds. The varicose fibers are projections from central or peripheral neurons that may extend over more than one segment. The peripheral fiber varicosities show segment-specific arrangements for each of the substances investigated. Immunoreactivity to histamine and octopamine is mainly found in the nerves of abdominal segments, whereas serotonin immunoreactivity is concentrated in subesophageal and terminal ganglion nerves. Immunoreactivity to FMRFamide and crustacean cardioactive peptide is widespread throughout all segments. Structures immunoreactive to leucokinin 1 are present in abdominal nerves, and proctolin immunostaining is found in the terminal ganglion and thoracic nerves. Codistribution of peripheral varicose fiber plexuses is regularly seen for amines and peptides, whereas the colocalization of substances in neurons has not been detected for any of the neuroactive compounds investigated. The varicose fiber system is regarded as complementary to the classical neurohemal organs.

  • 25. Hermann, Christiane
    et al.
    Saccon, Rachele
    Senthilan, Pingkalai R.
    Domnik, Lilith
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Yoshii, Taishi
    Helfrich-Foerster, Charlotte
    The circadian clock network in the brain of different Drosophila species2013Inngår i: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 521, nr 2, s. 367-388Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Comparative studies on cellular and molecular clock mechanisms have revealed striking similarities in the organization of the clocks among different animal groups. To gain evolutionary insight into the properties of the clock network within the Drosophila genus, we analyzed sequence identities and similarities of clock protein homologues and immunostained brains of 10 different Drosophila species using antibodies against vrille (VRI), PAR-protein domain1 (PDP1), and cryptochrome (CRY). We found that the clock network of both subgenera Sophophora and Drosophila consists of all lateral and dorsal clock neuron clusters that were previously described in Drosophila melanogaster. Immunostaining against CRY and the neuropeptide pigment-dispersing factor (PDF), however, revealed species-specific differences. All species of the Drosophila subgenus and D. pseudoobscura of the Sophophora subgenus completely lacked CRY in the large ventrolateral clock neurons (lLNvs) and showed reduced PDF immunostaining in the small ventrolateral clock neurons (sLNvs). In contrast, we found the expression of the ion transport peptide (ITP) to be consistent within the fifth sLNv and one dorsolateral clock neuron (LNd) in all investigated species, suggesting a conserved putative function of this neuropeptide in the clock. We conclude that the general anatomy of the clock network is highly conserved throughout the Drosophila genus, although there is variation in PDF and CRY expression. Our comparative study is a first step toward understanding the organization of the circadian clock in Drosophila species adapted to different habitats.

  • 26.
    Hofer, Sabine
    et al.
    Department of Biology, University of Marburg, D-35032 Marburg, Germany.
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Tollbäck, Petter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för analytisk kemi.
    Homberg, Uwe
    Department of Biology, University of Marburg, D-35032 Marburg, Germany.
    Novel insect orcokinins: characterization and neuronal distribution in the brains of selected dicondylian insects.2005Inngår i: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 490, nr 1, s. 57-71Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Orcokinins are a family of myotropic neuropeptides identified in various decapod crustaceans and recently in a cockroach. Their presence in the crustacean nervous system and hemolymph suggests that they act as hormones and as locally acting neuromodulators. To provide further evidence for the existence of orcokinins in insects, we identified a novel orcokinin-related peptide in the locust Schistocerca gregaria and used an antiserum against Asn13-orcokinin for immunostaining in the brains of selected dicondylian insects, including a silverfish, three polyneopteran species (a cockroach and two locusts), and three endopterygote species (a moth, a bee, and a fly). As analyzed by MALDI-TOF spectrometry and nanoelectrospray Q-TOF, the locust orcokinin is a novel tetradecapeptide with striking sequence similarity to crustacean orcokinins. Orcokinin immunostaining was widespread and occurred in similar patterns in the brain of the silverfish and the polyneopteran species. Prominent immunostaining was detected in the optic lobe, especially in the medulla and in the accessory medulla, in local interneurons of the antennal lobe, and in extrinsic and intrinsic mushroom-body neurons. All parts of the central complex and many other areas of the brains were densely stained. In the silverfish, the cockroach, and the locusts, processes in the corpora cardiaca showed orcokinin immunoreactivity, suggesting that orcokinins also serve a hormonal role. In contrast to the case in polyneopteran species, immunostaining was completely lacking in the brains of the honeybee, fruitfly, and sphinx moth. This indicates that orcokinins either are modified considerably or may be completely absent in the brains of endopterygote insects.

  • 27. Ignell, Rickard
    et al.
    Root, Cory M
    Birse, Ryan T
    Wang, Jing W
    Nässel, Dick R
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Winther, Åsa M E
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Presynaptic peptidergic modulation of olfactory receptor neurons in Drosophila.2009Inngår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 106, nr 31, s. 13070-13075Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The role of classical neurotransmitters in the transfer and processing of olfactory information is well established in many organisms. Neuropeptide action, however, is largely unexplored in any peripheral olfactory system. A subpopulation of local interneurons (LNs) in the Drosophila antannal lobe is peptidergic, expressing Drosophila tachykinins (DTKs). We show here that olfactory receptor neurons (ORNs) express the DTK receptor (DTKR). Using two-photon microscopy, we found that DTK applied to the antennal lobe suppresses presynaptic calcium and synaptic transmission in the ORNs. Furthermore, reduction of DTKR expression in ORNs by targeted RNA interference eliminates presynaptic suppression and alters olfactory behaviors. We detect opposite behavioral phenotypes after reduction and over expression of DTKR in ORNs. Our findings suggest a presynaptic inhibitory feedback to ORNs from peptidergic LNs in the antennal lobe.

  • 28. Jansen, Anna M
    et al.
    Nässel, Dick R
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Madsen, Kenneth L
    Jung, Anita G
    Gether, Ulrik
    Kjaerulff, Ole
    PICK1 expression in the Drosophila central nervous system primarily occurs in the neuroendocrine system.2009Inngår i: The Journal of comparative neurology, ISSN 1096-9861, Vol. 517, nr 3, s. 313-32Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The protein interacting with C kinase 1 (PICK1) protein was first identified as a novel binding partner for protein kinase C. PICK1 contains a membrane-binding BAR domain and a PDZ domain interacting with many synaptic proteins, including the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor subunit GluR2 and the dopamine transporter. PICK1 is strongly implicated in GluR2 trafficking and synaptic plasticity. In mammals, PICK1 has been characterized extensively in cell culture studies. To study PICK1 in an intact system, we characterized PICK1 expression immunohistochemically in the adult and larval Drosophila central nervous system. PICK1 was found in cell bodies in the subesophageal ganglion, the antennal lobe, the protocerebrum, and the neuroendocrine center pars intercerebralis. The cell types that express PICK1 were identified using GAL4 enhancer trap lines. The PICK1-expressing cells form a subpopulation of neurons. PICK1 immunoreactivity was neither detected in glutamatergic nor in dopaminergic neurons. Also, we observed PICK1 expression in only a few GABAergic neurons, located in the antennal lobe. In contrast, we detected robust PICK1 immunolabeling of peptidergic neurons in the neuroendocrine system, which express the transcription factor DIMM and the amidating enzyme peptidylglycine-alpha-hydroxylating monooxygenase (PHM). The PICK1-positive cells include neurosecretory cells that produce the insulin-like peptide dILP2. PICK1 expression in insulin-producing cells also occurs in mammals, as it was also observed in a rat insulinoma cell line derived from pancreatic beta-cells. At the subcellular level, PICK1 was found in the perinuclear zone but surprisingly not in synaptic domains. We conclude that PICK1 may serve an important role in the neuroendocrine system both in insects and vertebrates.

  • 29.
    Johard, Helena A D
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Yoishii, Taishi
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Cusumano, Paola
    Rouyer, Francois
    Helfrich-Förster, Charlotte
    Nässel, Dick R
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Peptidergic clock neurons in Drosophila: ion transport peptide and short neuropeptide F in subsets of dorsal and ventral lateral neurons2009Inngår i: The Journal of comparative neurology, ISSN 1096-9861, Vol. 516, nr 1, s. 59-73Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    About 150 clock neurons are clustered in different groups in the brain of Drosophila. Among these clock neurons, some pigment-dispersing factor (PDF)-positive and PDF-negative lateral neurons (LNs) are principal oscillators responsible for bouts of activity in the morning and evening, respectively. The full complement of neurotransmitters in these morning and evening oscillators is not known. By using a screen for candidate neuromediators in clock neurons, we discovered ion transport peptide (ITP) and short neuropeptide F (sNPF) as novel neuropeptides in subpopulations of dorsal (LN(d)s) and ventral (s-LN(v)s) LNs. Among the six LN(d)s, ITP was found in one that coexpresses long neuropeptide F (NPF) and cryptochrome. We detected sNPF in two LN(d)s that also express cryptochrome; these cells are distinct from three LN(d)s expressing NPF. Thus, we have identified neuropeptides in five of the six LN(d)s. The three LN(d)s expressing cryptochrome, with either ITP or sNPF, are the only ones with additional projections to the accessory medulla. Among the five s-LN(v)s in the adult brain, ITP was detected in the fifth neuron that is devoid of PDF and sNPF in the four neurons that also express PDF. By using a choline acetyltransferase (Cha) Gal4, we detected Cha expression in the two sNPF producing LN(d)s and in the fifth s-LN(v). In the larval brain, two of the four PDF-producing s-LN(v)s coexpress sNPF. Our findings emphasize that the LN(d)s are heterogeneous both anatomically and with respect to content of neuropeptides, cryptochrome, and other markers and suggest diverse functions of these neurons.

  • 30.
    Kahsai, Lily
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Kapan, Neval
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Winther, Åsa ME
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Nässel, Dick R
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Metabolic stress responses in Drosophila are modulated by brain neurosecretory cells that produce multiple neuropeptides2010Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 5, nr 7, s. e11480-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In Drosophila, neurosecretory cells that release peptide hormones play a prominent role in the regulation of development, growth, metabolism, and reproduction. Several types of peptidergic neurosecretory cells have been identified in the brain of Drosophila with release sites in the corpora cardiaca and anterior aorta. We show here that in adult flies the products of three neuropeptide precursors are colocalized in five pairs of large protocerebral neurosecretory cells in two clusters (designated ipc-1 and ipc-2a): Drosophila tachykinin (DTK), short neuropeptide F (sNPF) and ion transport peptide (ITP). These peptides were detected by immunocytochemistry in combination with GFP expression driven by the enhancer trap Gal4 lines c929 and Kurs-6, both of which are expressed in ipc-1 and 2a cells. This mix of colocalized peptides with seemingly unrelated functions is intriguing and prompted us to initiate analysis of the function of the ten neurosecretory cells. We investigated the role of peptide signaling from large ipc-1 and 2a cells in stress responses by monitoring the effect of starvation and desiccation in flies with levels of DTK or sNPF diminished by RNA interference. Using the Gal4-UAS system we targeted the peptide knockdown specifically to ipc-1 and 2a cells with the c929 and Kurs-6 drivers. Flies with reduced DTK or sNPF levels in these cells displayed decreased survival time at desiccation and starvation, as well as increased water loss at desiccation. Our data suggest that homeostasis during metabolic stress requires intact peptide signaling by ipc-1 and 2a neurosecretory cells.

  • 31.
    Kahsai Tesfai, Lily
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Nässel, Dick
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Winther, Åsa ME
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Distribution of metabotropic receptors of serotonin, dopamine, GABA andglutamate in the central complex of DrosophilaManuskript (preprint) (Annet vitenskapelig)
  • 32.
    Kapan, Neval
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    A search for reciprocal signaling between insulin and adipokinetic hormone producing cells in DrosophilaManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Insulin signaling in Drosophila regulates major physiological processes such as stress resistance, growth, carbohydrate and lipid metabolism, aging, reproduction and possibly diapause. Adipokinetic hormone (AKH) signaling originating from the corpora cardiaca (CC) cells, is another crucial regulator of hemolymph carbohydrate levels in Drosophila. These two systems are suggested to have opposing effects on lipid and sugar metabolism in Drosophila, reminiscent of the mammalian insulin and glucagon hormones. We studied the possible functional relationship between the insulin producing cells (IPCs) and the CC cells by interfering with insulin receptor (InR) and AKH receptor (AKH-R) expression on these cells. Our experiments revealed increased carbohydrate and lipid levels after knocking down InR in the CC cells. We also showed that diminished InR levels on the IPCs lead to increased starvation resistance, however we did not observe any changes in carbohydrate or lipid levels. So far we can only suggest action of insulins via its receptor on the IPCs and the CC cells, but we do not have conclusive data for AKH action on IPCs or CC cells.

  • 33.
    Kapan, Neval
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Lushchak, Oleh V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Luo, Jiangnan
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Nässel, Dick R.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Identified peptidergic neurons in the Drosophila brain regulate insulin-producing cells, stress responses and metabolism by coexpressed short neuropeptide F and corazonin2012Inngår i: Cellular and Molecular Life Sciences (CMLS), ISSN 1420-682X, E-ISSN 1420-9071, Vol. 69, nr 23, s. 4051-4066Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Insulin/IGF-like signaling regulates the development, growth, fecundity, metabolic homeostasis, stress resistance and lifespan in worms, flies and mammals. Eight insulin-like peptides (DILP1-8) are found in Drosophila. Three of these (DILP2, 3 and 5) are produced by a set of median neurosecretory cells (insulin-producing cells, IPCs) in the brain. Activity in the IPCs of adult flies is regulated by glucose and several neurotransmitters and neuropeptides. One of these, short neuropeptide F (sNPF), regulates food intake, growth and Dilp transcript levels in IPCs via the sNPF receptor (sNPFR1) expressed on IPCs. Here we identify a set of brain neurons that utilizes sNPF to activate the IPCs. These sNPF-expressing neurons (dorsal lateral peptidergic neurons, DLPs) also produce the neuropeptide corazonin (CRZ) and have axon terminations impinging on IPCs. Knockdown of either sNPF or CRZ in DLPs extends survival in flies exposed to starvation and alters carbohydrate and lipid metabolism. Expression of sNPF in DLPs in the sNPF mutant background is sufficient to rescue wild-type metabolism and response to starvation. Since CRZ receptor RNAi in IPCs affects starvation resistance and metabolism, similar to peptide knockdown in DLPs, it is likely that also CRZ targets the IPCs. Knockdown of sNPF, but not CRZ in DLPs decreases transcription of Dilp2 and 5 in the brain, suggesting different mechanisms of action on IPCs of the two co-released peptides. Our findings indicate that sNPF and CRZ co-released from a small set of neurons regulate IPCs, stress resistance and metabolism in adult Drosophila.

  • 34.
    Kress, Timm
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Harzsch, Steffen
    University of Greifswald, Germany.
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Neuroanatomy of the optic ganglia and central brain of the water flea Daphnia magna (Crustacea, Cladocera)2016Inngår i: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 363, nr 3, s. 649-677Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We reveal the neuroanatomy of the optic ganglia and central brain in the water flea Daphnia magna by use of classical neuroanatomical techniques such as semi-thin sectioning and neuronal backfilling, as well as immunohistochemical markers for synapsins, various neuropeptides and the neurotransmitter histamine. We provide structural details of distinct neuropiles, tracts and commissures, many of which were previously undescribed. We analyse morphological details of most neuron types, which allow for unravelling the connectivities between various substructural parts of the optic ganglia and the central brain and of ascending and descending connections with the ventral nerve cord. We identify 5 allatostatin-A-like, 13 FMRFamide-like and 5 tachykinin-like neuropeptidergic neuron types and 6 histamine-immunoreactive neuron types. In addition, novel aspects of several known pigment-dispersing hormone-immunoreactive neurons are re-examined. We analyse primary and putative secondary olfactory pathways and neuronal elements of the water flea central complex, which displays both insect- and decapod crustacean-like features, such as the protocerebral bridge, central body and lateral accessory lobes. Phylogenetic aspects based upon structural comparisons are discussed as well as functional implications envisaging more specific future analyses of ecotoxicological and endocrine disrupting environmental chemicals.

  • 35.
    Kubrak, Olga I.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Atamaniuk, Tetiana M.
    Husak, Viktor V.
    Lushchak, Volodymyr I.
    Transient effects of 2,4-dichlorophenoxyacetic acid (2,4-D) exposure on some metabolic and free radical processes in goldfish white muscle2013Inngår i: Food and Chemical Toxicology, ISSN 0278-6915, E-ISSN 1873-6351, Vol. 59, s. 356-361Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study aims to assess effects of 96 h goldfish exposure to 1, 10 and 100 mg/L of the herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), on metabolic indices and free radical process markers in white muscle of a commercial fish, the goldfish Carassius auratus L. Most oxidative stress markers and antioxidant enzymes were not affected at 2,4-D fish treatment. 2,4-D fish exposure induced the elevated levels of total (by 46% and 40%) and reduced (by 77% and 73%) glutathione in muscles of goldfish of 10 mg/L 2,4-D and recovery (after 100 mg/L of 2,4-D exposure) groups, respectively. However, in muscles of 100 mg/L 2,4-D exposed goldfish these parameters were depleted (by 47% and 64%). None of investigated parameters of protein and carbohydrate metabolisms changed in white muscles of 2,4-D exposed fish, with exception of lactate dehydrogenase activity, which was slightly (by 11-15%) elevated in muscles of goldfish exposed to 10-100 mg/L of 2,4-D, but also recovered. Thus, the short term exposure of goldfish to the selected concentrations of 2,4-D does not substantially affect their white muscle, suggesting the absence of any effect under the environmentally relevant concentrations. .

  • 36. Lebreton, Sébastien
    et al.
    Carlsson, Mikael A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Witzgall, Peter
    Insulin Signaling in the Peripheral and Central Nervous System Regulates Female Sexual Receptivity during Starvation in Drosophila2017Inngår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 8, s. 1-9, artikkel-id 685Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many animals adjust their reproductive behaviour according to nutritional state and food availability. Drosophila females for instance decrease their sexual receptivity following starvation. Insulin signalling, which regulates many aspects of insect physiology and behaviour, also affects reproduction in females. We show that insulin signalling is involved in the starvation-induced reduction in female receptivity. More specifically, females mutant for the insulin-like peptide 5 (dilp5) were less affected by starvation compared to the other dilp mutants and wild-type flies. Knocking-down the insulin receptor, either in all fruitless-positive neurons or a subset of these neurons dedicated to the perception of a male aphrodisiac pheromone, decreased the effect of starvation on female receptivity. Disrupting insulin signalling in some parts of the brain, including the mushroom bodies even abolished the effect of starvation. In addition, we identified fruitless-positive neurons in the dorso-lateral protocerebrum and in the mushroom bodies co-expressing the insulin receptor. Together, our results suggest that the interaction of insulin peptides determines the tuning of female sexual behaviour, either by acting on pheromone perception or directly in the central nervous system.

  • 37.
    Luo, Jiangnan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Becnel, Jaime
    Nichols, Charles D
    Nässel, Dick R
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Insulin-producing cells in the brain of adult Drosophila are regulated by the serotonin 5-HT(1A) receptor.2011Inngår i: Cellular and Molecular Life Sciences (CMLS), ISSN 1420-682X, E-ISSN 1420-9071, Vol. 69, nr 3, s. 471-484Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Insulin signaling regulates lifespan, reproduction, metabolic homeostasis, and resistance to stress in the adult organism. In Drosophila, there are seven insulin-like peptides (DILP1-7). Three of these (DILP2, 3 and 5) are produced in median neurosecretory cells of the brain, designated IPCs. Previous work has suggested that production or release of DILPs in IPCs can be regulated by a factor secreted from the fat body as well as by neuronal GABA or short neuropeptide F. There is also evidence that serotonergic neurons may regulate IPCs. Here, we investigated mechanisms by which serotonin may regulate the IPCs. We show that the IPCs in adult flies express the 5-HT(1A), but not the 5-HT(1B) or 5-HT(7) receptors, and that processes of serotonergic neurons impinge on the IPC branches. Knockdown of 5-HT(1A) in IPCs by targeted RNA interference (RNAi) leads to increased sensitivity to heat, prolonged recovery after cold knockdown and decreased resistance to starvation. Lipid metabolism is also affected, but no effect on growth was seen. Furthermore, we show that DILP2-immunolevels in IPCs increase after 5-HT(1A) knockdown; this is accentuated by starvation. Heterozygous 5-HT(1A) mutant flies display the same phenotype in all assays, as seen after targeted 5-HT(1A) RNAi, and flies fed the 5-HT(1A) antagonist WAY100635 display reduced lifespan at starvation. Our findings suggest that serotonin acts on brain IPCs via the 5-HT(1A) receptor, thereby affecting their activity and probably insulin signaling. Thus, we have identified a second inhibitory pathway regulating IPC activity in the Drosophila brain.

  • 38. Mangerich, Sigrid
    et al.
    Keller, Rainer
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Rao, K. Ranga
    Riehm, John P.
    Immunocytochemical localization of pigment-dispersing hormone (PDH) and its coexistence with FMRFamide-immunoreactive material in the eyestalks of the decapod crustaceans Carcinus maenas and Orconectes limosus1987Inngår i: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 250, s. 365-375Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    By use of a new antiserum, raised against synthetic pigment-dispersing hormone (PDH) from Uca pugilator, immunoreactive structures were studied at the light-microscopic level in the eyestalk ganglia of Carcinus maenas and Orconectes limosus. PDH-reactivity was mainly found in two types of neurons that were located between the medulla interna (MI) and the medulla terminalis (MT) in both species. Several additional perikarya were located in the distal part of the MI in O. limosus. In C. maenas, two to three PDH-positive perikarya were found in the region of the X-organ (XO) in the MT. Processes from single and clustered cells could be traced into all medullae of the eyestalk. Axons from the immunoreactive perikarya running between MI and MT form a larger tract that traverses the MT. Fibers from this tract give rise to extensive arborizations and plexuses throughout the proximal MT. A plexus containing very fine fibers is located at the surface of the MT in a position distal to the XO-area of C. maenas only. The proximal plexus also receives PDH-positive fibers through the optic nerve. PDH-perikarya in the cerebral ganglion may also project into the more distal regions of the eyestalk. Distal projections of the perikarya between the MI and MT consist of several branches. Most of these are directed toward the MI and ME (medulla externa) wherein they form highly organized, layered plexuses. One branch was traced into the principal neurohemal organ, the sinus gland (SG). In the SG, the tract gives off arborizations and neurosecretory terminals. It then proceeds in a proximal direction out of the SG, adjacent to the MT. Its further course could not be elucidated. The lamina ganglionaris (LG) receives PDH-fibers from the ME and fine processes from small perikarya located in close association with the LG in the distal part of the first optic chiasma. The architecture of PDH-positive elements was similar in both C. maenas and O. limosus. The distribution of these structures suggests that PDH is not only a neurohormone but may, in addition, have a role as a neurotransmitter or modulator. Immunostaining of successive sections with an FMRF-amide antiserum revealed co-localization of FMRFamideand PDH-immunoreactivities in most, but not all PDH-containing perikarya and fibers. The axonal branch leading to the SG and the SG proper were devoid of FMRFamide immunoreactivity.

  • 39. Mayer, Georg
    et al.
    Hering, Lars
    Stosch, Juliane M.
    Stevenson, Paul A.
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Evolution of pigment-dispersing factor neuropeptides in panarthropoda: Insights from onychophora (Velvet Worms) and tardigrada (Water Bears)2015Inngår i: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 523, nr 13, s. 1865-1885Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pigment-dispersing factor (PDF) denotes a conserved family of homologous neuropeptides present in several invertebrate groups, including mollusks, nematodes, insects and crustaceans (referred to here as pigment-dispersing hormone, PDH). Regarding their encoding genes (pdf, pdh), insects possess only one, nematodes two, and decapod crustaceans up to three, but their phylogenetic relationship is unknown. To shed light on the origin and diversification of pdf/pdh homologs in Panarthropoda (Onychophora + Tardigrada + Arthropoda) and other molting animals (Ecdysozoa), we analyzed the transcriptomes of five distantly related onychophorans and a representative tardigrade and searched for putative pdf homologs in publically available genomes of other protostomes. This revealed only one pdf homolog in several mollusk and annelid species, two in Onychophora, Priapulida and Nematoda, and three in Tardigrada. Phylogenetic analyses suggest that the last common ancestor of Panarthropoda possessed two pdf homologs, one of which was lost in the arthropod or arthropod/tardigrade lineage, followed by subsequent duplications of the remaining homolog in some taxa. Immunolocalization of PDF-like peptides in six onychophoran species, using a broadly reactive antibody that recognizes PDF/PDH peptides in numerous species, revealed an elaborate system of neurons and fibers in their central and peripheral nervous systems. Large varicose projections in the heart suggest that the PDF neuropeptides functioned as both circulating hormones and locally released transmitters in the last common ancestor of Onychophora and Arthropoda. The lack of PDF-like immunoreactive somata associated with the onychophoran optic ganglion conforms to the hypothesis that onychophoran eyes are homologous to the arthropod median ocelli.

  • 40. Nachman, Ronald J.
    et al.
    Mahdian, Kamran
    Nässel, Dick R.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Isaac, R. Elwyn
    Pryor, Nan
    Smagghe, Guy
    Biostable multi-Aib analogs of tachykinin-related peptides demonstrate potent oral aphicidal activity in the pea aphid Acyrthosiphon pisum (Hemiptera : Aphidae)2011Inngår i: Peptides, ISSN 0196-9781, E-ISSN 1873-5169, Vol. 32, nr 3, s. 587-594Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The tachykinin-related peptides (TRPs) are multifunctional neuropeptides found in a variety of arthropod species, including the pea aphid Acyrthosiphon pisum (Hemiptera: Aphidae). Two new biostable TRP analogs containing multiple, sterically hindered Aib residues were synthesized and found to exhibit significantly enhanced resistance to hydrolysis by angiotensin converting enzyme and neprilysin, membrane-bound enzymes that degrade and inactivate natural TRPs. The two biostable analogs were also found to retain significant myostimulatory activity in an isolated cockroach hindgut preparation, the bioassay used to isolate and identify the first members of the TRP family. Indeed one of the analogs (Leuma-TRP-Aib-1) matched the potency and efficacy of the natural, parent TRP peptide in this myotropic bioassay. The two biostable TRP analogs were further fed in solutions of artificial diet to the pea aphid over a period of 3 days and evaluated for antifeedant and aphicidal activity and compared with the effect of treatment with three natural, unmodified TRPs. The two biostable multi-Aib TRP analogs were observed to elicit aphicidal effects within the first 24h. In contrast natural, unmodified TRPs, including two that are native to the pea aphid, demonstrated little or no activity. The most active analog, double-Aib analog Leuma-TRP-Aib-1 (pEA[Aib]SGFL[Aib]VR-NH(2)), featured aphicidal activity calculated at an LC(50) of 0.0083nmol/μl (0.0087μg/μl) and an LT(50) of 1.4 days, matching or exceeding the potency of commercially available aphicides. The mechanism of this activity has yet to be established. The aphicidal activity of the biostable TRP analogs may result from disruption of digestive processes by interfering with gut motility patterns and/or with fluid cycling in the gut; processes shown to be regulated by the TRPs in other insects. These active TRP analogs and/or second generation analogs offer potential as environmentally friendly pest aphid control agents.

  • 41.
    Nässel, Dick
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Neuropeptide signaling near and far: how localized and timed is the action of neuropeptides in brain circuits?2009Inngår i: Invertebrate neuroscience, ISSN 1439-1104, Vol. 9, s. 57-75Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Neuropeptide signaling is functionally very diverse and one and the same neuropeptide may act as a circulating neurohormone, as a locally released neuromodulator or even as a cotransmitter of classical fast-acting neurotransmitters. Thus, neuropeptides are produced by a huge variety of neuron types in different parts of the nervous system. Within the central nervous system (CNS) there are numerous types of peptidergic interneurons, some with strictly localized and patterned branching morphologies, others with widespread and diffuse arborizations. From morphology alone it is often difficult to predict the sphere of influence of a peptidergic interneuron, especially since it has been shown that neuropeptides can diffuse over tens of micrometers within neuropils, and that peptides probably are released exclusively in perisynaptic (or non-synaptic) regions. This review addresses some questions related to peptidergic signaling in the insect CNS. How diverse are the spatial relations between peptidergic neurons and their target neurons and what determines the sphere of functional influence? At one extreme there is volume transmission and at the other targeted cotransmission at synapses. Also temporal aspects of peptidergic signaling are of interest: how transient are peptidergic messages? Factors important for these spatial and temporal aspects of peptidergic signaling are proximity between release sites and cognate receptors, distribution of peptidase activity that can terminate peptide action and colocalization of other neuroactive compounds in the presynaptic peptidergic neuron (and corresponding receptors in target neurons). Other factors such as expression of different channel types, receptor inactivation mechanisms and second messenger systems probably also contribute to the diversity in temporal properties of peptide signaling.

  • 42.
    Nässel, Dick
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Passier, Paul CCM
    Utrecht University.
    Elekes, Karoly
    Balaton Limnological Research Institute of the Hungarian Academy of Sciences,Tihany.
    Dircksen, Heinrich
    Institute of Zoophysiology, University of Bonn, Germany.
    Vullings, Henk G.B.
    Utrecht University.
    Cantera, Rafael
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Evidence that locustatachykinin I is involved in release of adipokinetic hormone from locust corpora cardiaca1995Inngår i: Regulatory Peptides, ISSN 0167-0115, E-ISSN 1873-1686, Vol. 57, nr 3, s. 297-310Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The glandular cells of the corpus cardiacum of the locust Locusta migratoria, known to synthesize and release adipokinetic hormones (AKH), are contacted by axons immunoreactive to an antiserum raised against the locust neuropeptide locustatachykinin I (LomTK I). Electron-microscopical immunocytochemistry reveals LomTK immunoreactive axon terminals, containing granular vesicles, in close contact with the glandular cells cells. Release of AKH I from isolated corpora cardiaca of the locust has been monitored in an in vitro system where the amount of AKH I released into the incubation saline is determined by reversed phase high performance liquid chromatography with fluorometric detection. We could show that LomTK I induces release of AKH from corpora cardiaca in a dose-dependent manner when tested in a range of 10-200 microM. This is thus the first clear demonstration of a substance inducing release of AKH, correlated with the presence of the substance in fibers innervating the AKH-synthesizing glandular cells, in the insect corpora cardiaca.

  • 43.
    Nässel, Dick R.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Bayraktaroglou, Emine
    Dircksen, Heinrich
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Neuropeptides in neurosecretory and efferent neural systems of insect thoracic and abdominal ganglia1994Inngår i: Zoological Science, ISSN 0289-0003, E-ISSN 2212-3830, Vol. 11, s. 15-31Artikkel i tidsskrift (Fagfellevurdert)
  • 44.
    Persson, Magnus G
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Eklund, Malin B
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Dircksen, Heinrich
    Institute of Zoophysiology, University of Bonn, Germany.
    Muren, J Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Nässel, Dick
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Pigment-dispersing factor in the locust abdominal ganglia may have roles as circulating neurohormone and central neuromodulator2001Inngår i: Journal of Neurobiology, ISSN 0022-3034, E-ISSN 1097-4695, Vol. 48, nr 1, s. 19-41Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pigment-dispersing factor (PDF) is a neuropeptide that has been indicated as a likely output signal from the circadian clock neurons in the brain of Drosophila. In addition to these brain neurons, there are PDF-immunoreactive (PDFI) neurons in the abdominal ganglia of Drosophila and other insects; the function of these neurons is not known. We have analyzed PDFI neurons in the abdominal ganglia of the locust Locusta migratoria. These PDFI neurons can first be detected at about 45% embryonic development and have an adult appearance at about 80%. In each of the abdominal ganglia (A3-A7) there is one pair of lateral PDFI neurons and in each of the A5-A7 ganglia there is additionally a pair of median neurons. The lateral neurons supply varicose branches to neurohemal areas of the lateral heart nerves and perisympathetic organs, whereas the median cells form processes in the terminal abdominal ganglion and supply terminals on the hindgut. Because PDF does not influence hindgut contractility, it is possible that also these median neurons release PDF into the circulation. Release from one or both the PDFI neuron types was confirmed by measurements of PDF-immunoreactivity in hemolymph by enzyme immunoassay. PDF applied to the terminal abdominal ganglion triggers firing of action potentials in motoneurons with axons in the genital nerves of males and the 8th ventral nerve of females. Because this action is blocked in calcium-free saline, it is likely that PDF acts via interneurons. Thus, PDF seems to have a modulatory role in central neuronal circuits of the terminal abdominal ganglion that control muscles of genital organs.

  • 45. Poels, Jeroen
    et al.
    Birse, Ryan T
    Nachman, Ronald J
    Fichna, Jakub
    Janecka, Anna
    Vanden Broeck, Jozef
    Nässel, Dick R
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Characterization and distribution of NKD, a receptor for Drosophila tachykinin-related peptide 6.2009Inngår i: Peptides, ISSN 0196-9781, E-ISSN 1873-5169, Vol. 30, nr 3, s. 545-56Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Neuropeptides related to vertebrate tachykinins have been identified in Drosophila and are referred to as drosotachykinins, or DTKs. Two Drosophila G protein-coupled receptors, designated NKD (neurokinin receptor from Drosophila; CG6515) and DTKR (Drosophila tachykinin receptor; CG7887), display sequence similarities to mammalian tachykinin receptors. Whereas DTKR was shown to be activated by DTKs [Birse RT, Johnson EC, Taghert PH, Nässel DR. Widely distributed Drosophila G-protein-coupled receptor (CG7887) is activated by endogenous tachykinin-related peptides. J Neurobiol 2006;66:33-46; Poels J, Verlinden H, Fichna J, Van Loy T, Franssens V, Studzian K, et al. Functional comparison of two evolutionary conserved insect neurokinin-like receptors. Peptides 2007;28:103-8] and was localized by immunocytochemistry in Drosophila central nervous system (CNS), agonist-dependent activation and distribution of NKD have not yet been investigated in depth. In the present study, we have challenged NKD-expressing mammalian and insect cells with a library of Drosophila neuropeptides and discovered DTK-6 as a specific agonist that can induce a calcium response in these cells. In addition, we have produced antisera to sequences from NKD protein to analyze receptor distribution. We found that NKD is less abundantly distributed in the central nervous system than DTKR, and only NKD was found in the intestine. In fact, the two receptors are distributed in mutually exclusive patterns in the CNS. The combined distribution of the receptors in brain neuropils corresponds well with the distribution of DTKs. Most interestingly, NKD appears to be activated only by DTK-6, known to possess an Ala-substitution in an otherwise conserved C-terminal core motif. Our findings suggest that NKD and DTKR provide substrates for two functionally and spatially separated peptide signaling systems.

  • 46. Santos, Jonathan G
    et al.
    Vömel, Matthias
    Struck, Rafael
    Homberg, Uwe
    Nässel, Dick R
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell morfologi.
    Wegener, Christian
    Neuroarchitecture of peptidergic systems in the larval ventral ganglion of Drosophila melanogaster.2007Inngår i: PLoS ONE, ISSN 1932-6203, Vol. 2, nr 1, s. e695-Artikkel i tidsskrift (Fagfellevurdert)
  • 47.
    Schäpers, Alexander
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Carlsson, Mikael A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Gamberale Stille, Gabriella
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Janz, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    The Role of Olfactory Cues for the Search Behavior of a Specialist and Generalist Butterfly2015Inngår i: Journal of insect behavior, ISSN 0892-7553, E-ISSN 1572-8889, Vol. 28, nr 1, s. 77-87Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Searching for resources is often a challenging task, especially for small organisms such as insects. Complex stimuli have to be extracted from the environment and translated into a relevant behavioral output. A first step in this process is to investigate the relative roles of the different senses during search for various resources. While the role of olfaction is well documented in nocturnal moths, the olfactory abilities of the closely related diurnal butterflies are poorly explored. Here we investigated how olfactory information is used in the search for host plants and asked if these abilities varied with levels of stimulus complexity. Thus, we tested two nymphalid butterfly species with divergent host plant range in a two-choice olfactometer testing different combinations of host and non-host plants. The experiments show both the monophagous Aglais urticae and the polyphagous Polygonia c-album could navigate towards an odor source, but this ability varied with context. While mated females exhibited a preference for their host plant, unmated females of both species did not show a preference for host plant cues. Furthermore, both species showed inabilities to make fine-tuned decisions between hosts. We conclude that olfactory cues are important for butterflies to navigate towards targets. We argue that there are limitations on how much information can be extracted from host volatiles. These results are discussed in the light of neural processing limitations and degree of host plant specialization, suggesting the necessity of other sensory modalities to sharpen the decision process and facilitate the final oviposition event.

  • 48.
    Schäpers, Alexander
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Nylin, Sören
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Carlsson, Mikael A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Janz, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Specialist and generalist oviposition strategies in butterflies: maternal care or precocious young?2016Inngår i: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 180, nr 2, s. 335-343Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herbivorous insects specialized on a narrow set of plants are believed to be better adapted to their specific hosts. This hypothesis is supported by observations of herbivorous insect species with a broader diet breadth which seemingly pay a cost through decreased oviposition accuracy. Despite many studies investigating female oviposition behavior, there is a lack of knowledge on how larvae cope behaviorally with their mothers' egg-laying strategies. We have examined a unique system of five nymphalid butterfly species with different host plant ranges that all feed on the same host plant. The study of this system allowed us to compare at the species level how oviposition preference is related to neonate larval responses in several disadvantageous situations. We found a general co-adaptation between female and larval abilities, where species with more discriminating females had larvae that were less able to deal with a suboptimal initial feeding site. Conversely, relatively indiscriminate females had more precocious larvae with better abilities to cope with suboptimal sites. Despite similarities between the tested species with similar host ranges, there were also striking differences. Generalist and specialist species can be found side by side in many clades, with each clade having a specific evolutionary history. Such clade-specific, phylogenetically determined preconditions apparently have affected how precisely a broad or narrow diet breadth can be realized.

  • 49.
    Shao, Yi Ta
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    GnRH mRNA levels in the brain of male three-spined stickleback, Gasterosteus aculeatus;effects of photoperiod, gonadectomy and breeding-postbreeding conditionArtikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    In vertebrates, reproduction is regulated by the brain-pituitary-gonad (BPG) axis where thegonadotropin- releasing hormone (GnRH) is one of the components. However, very little isknown about the possible role of GnRHs in environmental and feedback control of fishreproduction. To investigate this, GnRH2 (chicken II GnRH) and GnRH3 (salmon GnRH) mRNAlevels in male three-spined stickleback (Gasterosteus aculeatus), where GnRH1 is absent,were measured in different reproductive conditions; breeding or post-breeding, treated withlong (LD: 16:8) or short (LD: 8:16) photoperiod and castrated or sham-operated in thebreeding season. Using in situ hybridization, specific GnRH3 RNA probe labeled cells wereobserved in hypothalamus and pituitary and ventral telecephalon, but barely in other brainareas. GnRH2 expressing cells were mainly located in the mesencephalon and thalamus, butwere found in hypothalamus and pituitary as well. The GnRH3 mRNA levels were always farhigher than GnRH2. Breeding male brains had considerably higher levels of both GnRH2 andGnRH3 mRNA than post-breeding male brains. This suggests that both forms havereproductive functions. Fish kept under long photoperiod, which stimulated breeding, hadhigher mRNA levels of GnRH2, but not of GnRH3 which is probably the hypophysiotropicform, than fish kept under non-stimulatory short photoperiod. Thus, the higher expressionsof gonadotropins under long than under short photoperiod are not likely to be regulated viaGnRHs. Furthermore, castrated males’ brains showed lower GnRH2 and GnRH3 mRNA levelsthan sham-operated ones. This is consistent with that the positive feedback known toregulate lh-β in this phase could be exerted via GnRHs.

  • 50.
    Shao, Yi Ta
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Schulz, Rüdiger
    Borg, Bertil
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Homeostasis of circulating androgens levels in the male three-spined stickleback (Gasterosteus aculeatus)2012Inngår i: Zoological Studies, ISSN 1021-5506, E-ISSN 1810-522X, Vol. 51, nr 8, s. 1282-1289Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In mammals, plasma androgen levels are regulated by homeostatic feedbackmechanisms operating in the brain-pituitary-gonadal axis. However, some earlierstudies suggest that this may not be the case in all teleosts. This study aims atinvestigating to what extent androgens levels are homeostatically regulated in malethree-spined stickleback (Gasterosteus aculeatus), and whether aromatisation ofandrogens plays a role in this. To that end, breeding male sticklebacks were eithercompletely castrated or hemi-castrated or sham-operated, and implanted with differentdoses of 11- ketoandrostenedione (11KA) and testosterone (T) or with the aromataseinhibitor (AI) fadrozole. Hemi-castration alone diminished androgen levels andcomplete castration almost removed them. Low doses of 11KA and T increasedplasma androgen levels in castrated but not in sham-operated fish. Both low and highdoses of 11KA increased plasma 11-ketotestosterone (11KT) in hemi-castrated fish,whereas only the high dose of 11KA did so in sham-operated fish. If aromatizationplays a role in homeostatic mechanisms, androgen levels would be expected to rise insham-operated fish treated with AI. However, this was not the case. The reduction ofplasma androgen levels in fully mature hemi-castrated fish may suggest that theremaining testis is not able to increase its steroidogenesis further. However, both311KA and T treatments increased plasma levels much less in sham-operated fish thanin castrated ones, indicating that homeostatic mechanisms are nevertheless present.

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