The novel guanylyl cyclase MsGC-I is strongly expressed in higher-order neuropils in the brain of Manduca sexta

2001 ◽  
Vol 204 (2) ◽  
pp. 305-314 ◽  
Author(s):  
A. Nighorn ◽  
P.J. Simpson ◽  
D.B. Morton
Keyword(s):  
Nervous System ◽  
Manduca Sexta ◽  
Guanylyl Cyclase ◽  
Higher Order ◽  
Adult Brain ◽  
Central Complex ◽  
Amino Acid Residues ◽  
Order Processing ◽  
Guanylyl Cyclases ◽  
The Brain

Guanylyl cyclases are usually characterized as being either soluble (sGCs) or receptor (rGCs). We have recently cloned a novel guanylyl cyclase, MsGC-I, from the developing nervous system of the hawkmoth Manduca sexta that cannot be classified as either an sGC or an rGC. MsGC-I shows highest sequence identity with receptor guanylyl cyclases throughout its catalytic and dimerization domains, but does not contain the ligand-binding, transmembrane or kinase-like domains characteristic of receptor guanylyl cyclases. In addition, MsGC-I contains a C-terminal extension of 149 amino acid residues. In this paper, we report the expression of MsGC-I in the adult. Northern blots show that it is expressed preferentially in the nervous system, with high levels in the pharate adult brain and antennae. In the antennae, immunohistochemical analyses show that it is expressed in the cell bodies and dendrites, but not axons, of olfactory receptor neurons. In the brain, it is expressed in a variety of sensory neuropils including the antennal and optic lobes. It is also expressed in structures involved in higher-order processing including the mushroom bodies and central complex. This complicated expression pattern suggests that this novel guanylyl cyclase plays an important role in mediating cyclic GMP levels in the nervous system of Manduca sexta.

The Larval Eclosion Hormone Neurones in Manduca Sexta: Identification of the Brain-Proctodeal Neurosecretory System

1989 ◽  
Vol 147 (1) ◽  
pp. 457-470 ◽  
Author(s):  
JAMES W. TRUMAN ◽  
PHILIP F. COPENHAVER
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Manduca Sexta ◽  
Nerve Cord ◽  
Release Site ◽  
Neurosecretory System ◽  
Nerve Activity ◽  
Eclosion Hormone ◽  
The Central Nervous System ◽  
The Brain

Larval and pupal ecdyses of the moth Manduca sexta are triggered by eclosion hormone (EH) released from the ventral nervous system. The major store of EH activity in the latter resides in the proctodeal nerves that extend along the larval hindgut. At pupal ecdysis, the proctodeal nerves show a 90% depletion of stored activity, suggesting that they are the major release site for the circulating EH that causes ecdysis. Surgical experiments involving the transection of the nerve cord or removal of parts of the brain showed that the proctodeal nerve activity originates from the brain. Retrograde and anterograde cobalt fills and immunocytochemistry using antibodies against EH revealed two pairs of neurons that reside in the ventromedial region of the brain and whose axons travel ipsilaterally along the length of the central nervous system (CNS) and project into the proctodeal nerve, where they show varicose release sites. These neurons constitute a novel neuroendocrine pathway in insects which appears to be dedicated solely to the release of EH.

Neurodevelopment

2020 ◽  
pp. 91-100
Author(s):  
Karl Zilles ◽  
Nicola Palomero-Gallagher
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Neural Tube ◽  
Neural Plate ◽  
Adult Brain ◽  
The Central Nervous System ◽  
Specialized Region ◽  
The Brain ◽  
Rostral Part ◽  
Human Nervous System

The pre- and post-natal development of the human nervous system is briefly described, with special emphasis on the brain, particularly the cerebral and cerebellar cortices. The central nervous system originates from a specialized region of the ectoderm—the neural plate—which develops into the neural tube. The rostral part of the neural tube forms the adult brain, whereas the caudal part (behind the fifth somite) differentiates into the spinal cord. The embryonic brain has three vesicular enlargements: the forebrain, the midbrain, and the hindbrain. The histogenesis of the spinal cord, hindbrain, cerebellum, and cerebral cortex, including myelination, is discussed. The chapter closes with a description of the development of the hemispheric shape and the formation of gyri.

scholarly journals Functional analysis of enhancer elements regulating the expression of the Drosophila homeodomain transcription factor DRx by gene targeting

Hereditas ◽  
2021 ◽  
Vol 158 (1) ◽  
Author(s):  
Christine Klöppel ◽  
Kirsten Hildebrandt ◽  
Dieter Kolb ◽  
Nora Fürst ◽  
Isabelle Bley ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Brain Development ◽  
Gene Targeting ◽  
Developmental Stages ◽  
Expression Patterns ◽  
Adult Brain ◽  
Central Complex ◽  
Larval Brain ◽  
Endogenous Expression ◽  
The Brain

Abstract Background The Drosophila brain is an ideal model system to study stem cells, here called neuroblasts, and the generation of neural lineages. Many transcriptional activators are involved in formation of the brain during the development of Drosophila melanogaster. The transcription factor Drosophila Retinal homeobox (DRx), a member of the 57B homeobox gene cluster, is also one of these factors for brain development. Results In this study a detailed expression analysis of DRx in different developmental stages was conducted. We show that DRx is expressed in the embryonic brain in the protocerebrum, in the larval brain in the DM and DL lineages, the medulla and the lobula complex and in the central complex of the adult brain. We generated a DRx enhancer trap strain by gene targeting and reintegration of Gal4, which mimics the endogenous expression of DRx. With the help of eight existing enhancer-Gal4 strains and one made by our group, we mapped various enhancers necessary for the expression of DRx during all stages of brain development from the embryo to the adult. We made an analysis of some larger enhancer regions by gene targeting. Deletion of three of these enhancers showing the most prominent expression patterns in the brain resulted in specific temporal and spatial loss of DRx expression in defined brain structures. Conclusion Our data show that DRx is expressed in specific neuroblasts and defined neural lineages and suggest that DRx is another important factor for Drosophila brain development.

Physiology of Insect Ecdysis

1973 ◽  
Vol 58 (3) ◽  
pp. 821-829
Author(s):  
JAMES W. TRUMAN
Keyword(s):  
Nervous System ◽  
Manduca Sexta ◽  
Hormone Activity ◽  
Hormonal Factors ◽  
Corpora Cardiaca ◽  
Eclosion Hormone ◽  
Neural Input ◽  
The Brain ◽  
Pupal Cuticle

1. In pharate Manduca sexta moths eclosion hormone activity was present in the brain and corpora cardiaca. Bursicon activity was confined to the abdominal nervous system, and was most concentrated in the abdominal perivisceral organs (PVOs). 2. When newly emerged moths were given access to suitable wing-spreading sites, bursicon activity was depleted from the PVOs and appeared in the blood within 15 min after eclosion. This hormone was responsible for the tanning and hardening of the wings. 3. Bursicon release could be delayed for at least 24 h by forcing the newly emerged moth to dig. Secretion then occurred swiftly upon giving the moth a suitable wing-spreading site. 4. The pupal cuticle was removed from pharate Manduca approximately 7 h before their normal eclosion gate, and the peeled moths were provided with a wing-spreading site. These moths did not then secrete bursicon until after their normal time of eclosion. 5. Injection of the eclosion hormone into pharate moths caused early eclosion followed by precocious bursicon secretion. 6. It was concluded that bursicon release is regulated by both neural and hormonal factors. The eclosion hormone triggers a program of neural output which includes the secretion of bursicon. This release, however, can be delayed by neural input which is associated with the digging behaviour of the moth.

scholarly journals Evidence for the cholinergic markers ChAT and vAChT in sensory cells of the developing antennal nervous system of the desert locust Schistocerca gregaria

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Erica Ehrhardt ◽  
George Boyan
Keyword(s):  
Nervous System ◽  
Schistocerca Gregaria ◽  
Central Complex ◽  
Sensory Cells ◽  
Desert Locust ◽  
Cholinergic Transmission ◽  
Sensory Axons ◽  
First Instar ◽  
The Brain ◽  
Antennal Nerve

AbstractSensory and motor systems in insects with hemimetabolous development must be ready to mediate adaptive behavior directly on hatching from the egg. For the desert locust S. gregaria, cholinergic transmission from antennal sensillae to olfactory or mechanosensory centers in the brain requires that choline acetyltransferase (ChAT) and the vesicular acetylcholine transporter (vAChT) already be present in sensory cells in the first instar. In this study, we used immunolabeling to demonstrate that ChAT and vAChT are both expressed in sensory cells from identifiable sensilla types in the immature antennal nervous system. We observed ChAT expression in dendrites, neurites and somata of putative basiconic-type sensillae at the first instar stage. We also detected vAChT in the sensory axons of these sensillae in a major antennal nerve tract. We then examined whether evidence for cholinergic transmission is present during embryogenesis. Immunolabeling confirms that vAChT is expressed in somata typical of campaniform sensillae, as well as in small sensory cell clusters typically associated with either a large basiconic or coeloconic sensilla, at 99% of embryogenesis. The vAChT is also expressed in the somata of these sensilla types in multiple antennal regions at 90% of embryogenesis, but not at earlier (70%) embryonic stages. Neuromodulators are known to appear late in embryogenesis in neurons of the locust central complex, and the cholinergic system of the antenna may also only reach maturity shortly before hatching.

scholarly journals Type 3 Deiodinase Deficiency Causes Spatial and Temporal Alterations in Brain T3 Signaling that Are Dissociated from Serum Thyroid Hormone Levels

Endocrinology ◽  
2010 ◽  
Vol 151 (11) ◽  
pp. 5550-5558 ◽  
Author(s):  
Arturo Hernandez ◽  
Laure Quignodon ◽  
M. Elena Martinez ◽  
Frederic Flamant ◽  
Donald L. St. Germain
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Elevated Serum ◽  
Adult Brain ◽  
Neural Function ◽  
Peripheral Tissues ◽  
Show Evidence ◽  
The Central Nervous System ◽  
Type 3 ◽  
The Brain

The type 3 deiodinase (D3) is an enzyme that inactivates thyroid hormones (TH) and is highly expressed during development and in the central nervous system. D3-deficient (D3KO) mice develop markedly elevated serum T3 level in the perinatal period. In adulthood, circulating T4 and T3 levels are reduced due to functional deficits in the thyroid axis and peripheral tissues (i.e. liver) show evidence of decreased TH action. Given the importance of TH for brain development, we aimed to assess TH action in the brain of D3KO mice at different developmental stages and determine to what extent it correlates with serum TH parameters. We used a transgenic mouse model (FINDT3) that expresses the reporter gene β-galactosidase (β-gal) in the central nervous system as a readout of local TH availability. Together with experiments determining expression levels of TH-regulated genes, our results show that after a state of thyrotoxicosis in early development, most regions of the D3KO brain show evidence of decreased TH action at weaning age. However, later in adulthood and in old age, the brain again manifests a thyrotoxic state, despite reduced serum TH levels. These region-specific changes in brain TH status during the life span of the animal provide novel insight into the important role of the D3 in the developing and adult brain. Our results suggest that, even if serum concentrations of TH are normal or low, impaired D3 activity may result in excessive TH action in multiple brain regions, with potential consequences of altered neural function that may be of clinical relevance to neurological and neuroendocrine disorders.

scholarly journals The initiation of pre-ecdysis and ecdysis behaviors in larval Manduca sexta: the roles of the brain, terminal ganglion and eclosion hormone.

1996 ◽  
Vol 199 (8) ◽  
pp. 1757-1769 ◽  
Author(s):  
A Novicki ◽  
J C Weeks
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Manduca Sexta ◽  
Brain Neurons ◽  
Eclosion Hormone ◽  
Terminal Ganglion ◽  
The Central Nervous System ◽  
Time Required ◽  
The Brain ◽  
Larval Molt

Each larval molt of Manduca sexta culminates in the sequential performance of pre-ecdysis (cuticle loosening) and ecdysis (cuticle shedding) behaviors. Both behaviors are thought to be triggered by the release of a peptide, eclosion hormone (EH), from brain neurons whose axons extend the length of the nervous system. EH bioactivity appears in the hemolymph at the onset of pre-ecdysis behavior, and EH injection can trigger pre-ecdysis and ecdysis behaviors prematurely. The present study examined the effects of removing or disconnecting portions of the central nervous system prior to the time of EH release on the initiation of pre-ecdysis and ecdysis behaviors at the final larval molt. We found that the initiation of pre-ecdysis abdominal compressions at the appropriate time required the terminal abdominal ganglion (AT) but not the brain; the initiation of pre-ecdysis proleg retractions at the appropriate time required neither the AT nor the brain; the initiation of ecdysis at the appropriate time usually required the brain but did not require the AT; and premature pre-ecdysis (but not ecdysis) could be elicited in isolated abdomens by injection of EH. Finally, pre-ecdysis behavior performed by brainless larvae was not associated with the normal elevation of EH bioactivity in the hemolymph or the normal loss of EH immunoreactivity from peripheral neurohemal release sites.

Expression of the Drosophila optomotor-blind gene transcript in neuronal and glial cells of the developing nervous system

Development ◽  
1993 ◽  
Vol 117 (3) ◽  
pp. 1017-1029 ◽  
Author(s):  
B. Poeck ◽  
A. Hofbauer ◽  
G.O. Pflugfelder
Keyword(s):  
Nervous System ◽  
Embryonic Development ◽  
Optic Lobe ◽  
Adult Brain ◽  
Gene Transcript ◽  
Larval Brain ◽  
Ventral Ganglion ◽  
Optic Lobes ◽  
Central Brain ◽  
The Brain

Mutations in the complex gene locus optomotor-blind (omb) can lead to defects in the development of both the optic lobes and external features of the adult fly. We describe here the expression of omb in the developing and adult nervous system using in situ hybridization. During embryogenesis, omb expression is first observed in the optic lobe anlagen. It later expands to a larger part of the developing larval brain and to the gnathal lobes. Cells in the ventral and peripheral nervous systems begin to express omb after completion of germ band extension. Later in embryonic development, expression declines and only persists in the antennomaxillary complex and in part of the brain hemispheres. During the larval and pupal stages, omb expression in the brain is confined to the developing optic lobes and contiguous regions of the central brain. At these stages, only a few cells show expression in the ventral ganglion. In the eye imaginal disc, transcript accumulation is most conspicuous in a group of presumptive glia precursor cells posterior to the morphogenetic furrow and in the optic stalk. In the adult brain, expression is prominent in several regions of the optic lobe cortex and along the border between central brain and optic lobes. In the mutation In(1)ombH31, 40 kb of regulatory DNA, downstream from the transcription unit, are removed from the omb gene. In(1)ombH31 is characterized by the lack of a set of giant interneurons from the lobula plate of the adult optic lobes. We find that, already during embryogenesis, there is a drastic difference between wild type and In(1)ombH31 in the level of the omb transcript in the optic lobe primordia. The adult mutant phenotype may thus be caused by omb misexpression during embryonic development.

scholarly journals The physiology of wandering behaviour in Manduca sexta. IV. Hormonal induction of wandering behaviour from the isolated nervous system

1986 ◽  
Vol 121 (1) ◽  
pp. 133-151 ◽  
Author(s):  
O. S. Dominick ◽  
J. W. Truman
Keyword(s):  
Nervous System ◽  
Manduca Sexta ◽  
Extracellular Recording ◽  
Behavioural Effects ◽  
Average Latency ◽  
Motor Nerves ◽  
Spontaneous Bursts ◽  
Necessary And Sufficient ◽  
Manduca Sexta Larvae ◽  
The Brain

Prior to exposure to ecdysteroids, the isolated central nervous system (CNS) of the fifth instar Manduca sexta larvae exhibited infrequent motor bursts over a 24-h period of extracellular recording from segmental motor nerves. In contrast, the CNS isolated from wandering larvae was characterized by persistent, frequent spontaneous motor bursts throughout the 24-h incubation. The motor bursts generated by the isolated CNS of wandering larvae were similar to those observed in deafferented segments of partially dissected wandering larvae during locomotion. In both cases bursts in the deafferented ganglia were synchronous and had a lower frequency than in intact animals. Removal of the brain from a CNS isolated prior to ecdysteroid exposure resulted in the appearance of spontaneous bursts, which were abolished by removing the suboesophageal ganglion (SEG). By contrast, when the brain was removed from the isolated CNS of wandering larvae, spontaneous bursts ceased. These results parallel the behavioural effects of the same lesions in intact larvae of the respective stages. The CNS isolated from larvae prior to ecdysteroid exposure initiated sustained frequent bursting after an average latency of 15 h following incubation in haemolymph taken from larvae during the interval of ecdysteroid secretion. Incubations of the CNS with 1 microgram ml-1 20-hydroxyecdysone (20-HE) resulted in the onset of the same pattern of sustained motor activity. In a CNS isolated prior to ecdysone release, it was necessary and sufficient to expose the brain to 20-HE in order to induce the state of persistent motor bursts characteristic of wandering. We conclude that the spontaneous persistent motor bursts observed in the isolated CNS of wandering larvae are directly related to the sustained locomotion seen during the wandering behaviour. 20-HE acts directly on the CNS, specifically the brain, to induce this state of neural activity.

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