48 research outputs found
The Satiety Signaling Neuropeptide Perisulfakinin Inhibits the Activity of Central Neurons Promoting General Activity
The metabolic state is one of the determinants of the general activity level. Satiety is related to resting or sleep whereas hunger correlates to wakefulness and activity. The counterpart to the mammalian satiety signal cholecystokinin (CCK) in insects are the sulfakinins. The aim of this study was to resolve the mechanism by which the antifeedant activity of perisulfakinin (PSK) in Periplaneta americana is mediated. We identified the sources of PSK which is used both as hormone and as paracrine messenger. PSK is found in the neurohemal organ of the brain and in nerve endings throughout the central nervous system. To correlate the distributions of PSK and its receptor (PSKR), we cloned the gene coding for PSKR and provide evidence for its expression within the nervous system. It occurs only in a few neurons, among them are the dorsal unpaired median (DUM) neurons which release octopamine thereby regulating the general level of activity. Application of PSK to DUM neurons attenuated the spiking frequency (EC50=11pM) due to reduction of a pacemaker Ca2+ current through cAMP-inhibited pTRPγ channels. PSK increased the intracellular cAMP level while decreasing the intracellular Ca2+ concentration in DUM neurons. Thus, the satiety signal conferred by PSK acts antagonistically to the hunger signal, provided by the adipokinetic hormone (AKH): PSK depresses the electrical activity of DUM neurons by inhibiting the pTRPγ channel that is activated by AKH under conditions of food shortage
A Novel Giant Non-Cholinergic Striatal Interneuron Restricted to the Ventrolateral Striatum Coexpresses Kv3.3 Potassium Channel, Parvalbumin, and the Vesicular GABA Transporter
Cellular localization of the potassium channel Kir7.1 in guinea pig and human kidney
Cellular localization of the potassium channel Kir7.1 in guinea pig and human kidney.BackgroundK+ channels have important functions in the kidney, such as maintenance of the membrane potential, volume regulation, recirculation, and secretion of potassium ions. The aim of this study was to obtain more information on the localization and possible functional role of the inwardly rectifying K+ channel, Kir7.1.MethodsKir7.1 cDNA (1114 bp) was isolated from guinea pig kidney (gpKir7.1), and its tissue distribution was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR). In addition, a genomic DNA fragment (6153 bp) was isolated from a genomic library. cRNA was expressed in Xenopus laevis oocytes for functional studies. Immunohistochemistry and RT-PCR were used to localize Kir7.1 in guinea pig and human kidney.ResultsThe expression of gpKir7.1 in Xenopus laevis oocytes revealed inwardly rectifying K+ currents. The reversal potential was strongly dependent on the extracellular K+ concentration, shifting from -14 mV at 96 mmol/L K+ to -90 mV at 1 mmol/L K+. gpKir7.1 showed a low affinity for Ba2+. Significant expression of gpKir7.1 was found in brain, kidney, and lung, but not in heart, skeletal muscle, liver, or spleen. Immunocytochemical detection in guinea pig identified the gpKir7.1 protein in the basolateral membrane of epithelial cells of the proximal tubule. RT-PCR analysis identified strong gpKir7.1 expression in the proximal tubule and weak expression in glomeruli and thick ascending limb. In isolated human tubule fragments, RT-PCR showed expression in proximal tubule and thick ascending limb.ConclusionOur results suggest that Kir7.1 may contribute to basolateral K+ recycling in the proximal tubule and in the thick ascending limb
Unique Features of a Global Human Ectoparasite Identified Through Sequencing of the Bed Bug Genome
The bed bug, Cimex lectularius, has re-established itself as a ubiquitous human ectoparasite throughout much of the world during the past two decades. This global resurgence is likely linked to increased international travel and commerce in addition to widespread insecticide resistance. Analyses of the C. lectularius sequenced genome (650 Mb) and 14,220 predicted protein-coding genes provide a comprehensive representation of genes that are linked to traumatic insemination, a reduced chemosensory repertoire of genes related to obligate hematophagy, host-symbiont interactions, and several mechanisms of insecticide resistance. In addition, we document the presence of multiple putative lateral gene transfer events. Genome sequencing and annotation establish a solid foundation for future research on mechanisms of insecticide resistance, human-bed bug and symbiont-bed bug associations, and unique features of bed bug biology that contribute to the unprecedented success of C. lectularius as a human ectoparasite
Unique features of a global human ectoparasite identified through sequencing of the bed bug genome
The bed bug, Cimex lectularius, has re-established itself as a ubiquitous
human ectoparasite throughout much of the world during the past two decades.
This global resurgence is likely linked to increased international travel and
commerce in addition to widespread insecticide resistance. Analyses of the C.
lectularius sequenced genome (650 Mb) and 14,220 predicted protein-coding
genes provide a comprehensive representation of genes that are linked to
traumatic insemination, a reduced chemosensory repertoire of genes related to
obligate hematophagy, host–symbiont interactions, and several mechanisms of
insecticide resistance. In addition, we document the presence of multiple
putative lateral gene transfer events. Genome sequencing and annotation
establish a solid foundation for future research on mechanisms of insecticide
resistance, human–bed bug and symbiont–bed bug associations, and unique
features of bed bug biology that contribute to the unprecedented success of C.
lectularius as a human ectoparasite
Sequence and expression of per, tim1, and cry2 genes in the Madeira Cockroach Rhyparobia maderae
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich. - This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively
Neuropeptidomics of the Bed Bug Cimex lectularius
The bed bug Cimex lectularius is a globally distributed human ectoparasite with fascinating biology. It has recently acquired resistance against a broad range of insecticides, causing a worldwide increase in bed bug infestations. The recent annotation of the bed bug genome revealed a full complement of neuropeptide and neuropeptide receptor genes in this species. With regard to the biology of C. lectularius, neuropeptide signaling is especially interesting because it regulates feeding, diuresis, digestion, as well as reproduction and also provides potential new targets for chemical control. To identify which neuropeptides are translated from the genome-predicted genes, we performed a comprehensive peptidomic analysis of the central nervous system of the bed bug. We identified in total 144 different peptides from 29 precursors, of which at least 67 likely present bioactive mature neuropeptides. C. lectularius corazonin and myosuppressin are unique and deviate considerably from the canonical insect consensus sequences. Several identified neuropeptides likely act as hormones, as evidenced by the occurrence of respective mass signals and immunoreactivity in neurohemal structures. Our data provide the most comprehensive peptidome of a Heteropteran species so far and in comparison suggest that a hematophageous life style does not require qualitative adaptations of the insect peptidome
Identification of two capa cDNA transcripts and detailed peptidomic characterization of their peptide products in Periplaneta americana
The first CAPA peptides of insects were identified from Periplaneta americana using extracts of 8000 abdominal perisympathetic organs. The corresponding gene of cockroaches and other basal insects, however, remained undiscovered. Here we identified two capa cDNA transcripts of P. americana. Single cell mass spectrometry of capa neurons in abdominal ganglia yielded a complete coverage of the precursor sequences of both transcripts; with intermediates of precursor processing more prominent in somata than in perisympathetic organs. The processing of the CAPA precursor in P. americana is compared with that in the beetle Tribolium castaneum which was re-evaluated in this study
Voltage‐gated proton channels in polyneopteran insects
Voltage‐gated proton channels (H(V)1) are expressed in eukaryotes, including basal hexapods and polyneopteran insects. However, currently, there is little known about H(V)1 channels in insects. A characteristic aspartate (Asp) that functions as the proton selectivity filter (SF) and the RxWRxxR voltage‐sensor motif are conserved structural elements in H(V)1 channels. By analysing Transcriptome Shotgun Assembly (TSA) databases, we found 33 polyneopteran species meeting these structural requirements. Unexpectedly, an unusual natural variation Asp to glutamate (Glu) at SF was found in Phasmatodea and Mantophasmatodea. Additionally, we analysed the expression and function of H(V)1 in the phasmatodean stick insect Extatosoma tiaratum (Et). EtH(V)1 is strongly expressed in nervous tissue and shows pronounced inward proton conduction. This is the first study of a natural occurring Glu within the SF of a functional H(V)1 and might be instrumental in uncovering the physiological function of H(V)1 in insects
Neuropeptidomics of the Bed Bug <i>Cimex lectularius</i>
The bed bug <i>Cimex lectularius</i> is a globally distributed
human ectoparasite with fascinating biology. It has recently acquired
resistance against a broad range of insecticides, causing a worldwide
increase in bed bug infestations. The recent annotation of the bed
bug genome revealed a full complement of neuropeptide and neuropeptide
receptor genes in this species. With regard to the biology of <i>C. lectularius</i>, neuropeptide signaling is especially interesting
because it regulates feeding, diuresis, digestion, as well as reproduction
and also provides potential new targets for chemical control. To identify
which neuropeptides are translated from the genome-predicted genes,
we performed a comprehensive peptidomic analysis of the central nervous
system of the bed bug. We identified in total 144 different peptides
from 29 precursors, of which at least 67 likely present bioactive
mature neuropeptides. <i>C. lectularius</i> corazonin and
myosuppressin are unique and deviate considerably from the canonical
insect consensus sequences. Several identified neuropeptides likely
act as hormones, as evidenced by the occurrence of respective mass
signals and immunoreactivity in neurohemal structures. Our data provide
the most comprehensive peptidome of a Heteropteran species so far
and in comparison suggest that a hematophageous life style does not
require qualitative adaptations of the insect peptidome