Molecular cloning and function of ecdysis-triggering hormones in the silkwormBombyx mori

2002 ◽  
Vol 205 (22) ◽  
pp. 3459-3473 ◽  
Author(s):  
Dušan Žitňan ◽  
Laura Hollar ◽  
Ivana Spalovská ◽  
Peter Takáč ◽  
Inka Žitňanová ◽  
...  
Keyword(s):  
Direct Action ◽  
Endocrine System ◽  
Cell Extract ◽  
Guanosine Monophosphate ◽  
Inka Cells ◽  
And Function ◽  
Ecdysis Triggering Hormone ◽  
Strong Immunoreactivity ◽  
Behavioural Sequence

SUMMARYInka cells of the epitracheal endocrine system produce peptide hormones involved in the regulation of insect ecdysis. In the silkworm Bombyx mori, injection of Inka cell extract into pharate larvae, pupae or adults activates the ecdysis behavioural sequence. In the present study, we report the identification of three peptides in these extracts, pre-ecdysis-triggering hormone (PETH), ecdysis-triggering hormone (ETH) and ETH-associated peptide(ETH-AP), which are encoded by the same cDNA precursor. Strong immunoreactivity associated with each peptide in Inka cells prior to ecdysis disappears during each ecdysis, indicating complete release of these peptides. Injection of either PETH or ETH alone is sufficient to elicit the entire ecdysis behavioural sequence through the direct action on abdominal ganglia;cephalic and thoracic ganglia are not required for the transition from pre-ecdysis to ecdysis behaviour. Our in vitro data provide evidence that these peptides control the entire ecdysis behavioural sequence through activation of specific circuits in the nervous system. Ecdysis of intact larvae is associated with the central release of eclosion hormone (EH) and elevation of cyclic 3′,5′-guanosine monophosphate (cGMP) in the ventral nerve cord. However, injection of ETH into isolated abdomens induces cGMP elevation and ecdysis behaviour without a detectable release of EH,suggesting that an additional central factor(s) may be involved in the activation of this process. Our findings provide the first detailed account of the natural and hormonally induced behavioural sequence preceding larval,pupal and adult ecdyses of B. mori and highlight significant differences in the neuro-endocrine activation of pre-ecdysis and ecdysis behaviours compared with the related moth, Manduca sexta.

Ecdysteroids regulate secretory competence in Inka cells

2000 ◽  
Vol 203 (19) ◽  
pp. 3011-3018 ◽  
Author(s):  
T.G. Kingan ◽  
M.E. Adams
Keyword(s):  
Cyclic Gmp ◽  
Actinomycin D ◽  
Receptor Activation ◽  
Inhibitory Effects ◽  
Late Event ◽  
Nuclear Events ◽  
Inka Cells ◽  
Ecdysis Triggering Hormone ◽  
Overnight Culture

Ecdysis, or molting behavior, in insects requires the sequential action of high levels of ecdysteroids, which induce accumulation of ecdysis-triggering hormone (ETH) in Inka cells, followed by low levels of ecdysteroids, permissive for the onset of the behavior. Here, we show that high ecdysteroid levels suppress the onset of the behavioral sequence by inhibiting the development of competence to secrete ETH. In pharate pupae of Manduca sexta, Inka cells in the epitracheal glands normally develop competence to secrete ETH in response to eclosion hormone (EH) 8 h before pupation. Injection of 20-hydroxyecdysone (20E) into precompetent insects prevents this acquisition of competence, but does not affect EH-evoked accumulation of the second messenger cyclic GMP. Precompetent glands acquire competence in vitro after overnight culture, and this can be prevented by the inclusion of 20E at concentrations greater than 0.1 microg ml(−1)in the culture medium. Actinomycin D completely inhibits the acquisition of competence, demonstrating that it is dependent on transcriptional events. Cultured epitracheal glands become refractory to the inhibitory effects of 20E in the acquisition of competence at least 3 h earlier than for Actinomycin D, indicating that 20E acts on an early step in a sequence of nuclear events leading to transcription of a structural gene. Our findings suggest that declining ecdysteroid levels permit a late event in transcription, the product of which is downstream of EH receptor activation and cyclic GMP accumulation in the cascade leading to ETH secretion.

Regulation of ecdysis-triggering hormone release by eclosion hormone.

1997 ◽  
Vol 200 (24) ◽  
pp. 3245-3256 ◽  
Author(s):  
T G Kingan ◽  
W Gray ◽  
D Zitnan ◽  
M E Adams
Keyword(s):  
Endocrine System ◽  
Threshold Concentration ◽  
Hormone Release ◽  
Initial Portion ◽  
Eclosion Hormone ◽  
Direct Exposure ◽  
Secretory Action ◽  
The Central Nervous System ◽  
Ecdysis Triggering Hormone

Ecdysis behavior in the tobacco hornworm Manduca sexta (Lepidoptera: Sphingidae) is triggered through reciprocal peptide signaling between the central nervous system and the epitracheal endocrine system. Recent evidence indicates that eclosion hormone may initiate endocrine events leading to ecdysis through its action on epitracheal glands to cause the release of ecdysis-triggering hormone (ETH). Here, we report that direct exposure of epitracheal glands to eclosion hormone in vitro leads to secretion of ETH. The threshold concentration of eclosion hormone needed to evoke release of ETH is approximately 3 pmol l-1. Eclosion hormone also induces elevation of cyclic GMP, but not cAMP, concentration in epitracheal glands at concentrations similar to those causing release of ETH. Both cGMP and 8-Br-cGMP mimic the secretory action of eclosion hormone. The sensitivity of the secretory response to eclosion hormone occurs during a narrow window of development, beginning approximately 8 h prior to pupal ecdysis. However, eclosion hormone can cause elevation of cGMP levels in epitracheal glands long before they acquire competence to release ETH, showing that the initial portion of the signal transduction cascade is in place early in development, but that the absence of a downstream step in the cascade prevents secretion. Measurements of cGMP levels in epitracheal glands during the ecdysis sequence show a sudden elevation some 30 min after the onset of pre-ecdysis, well after ETH secretion has been initiated. ETH secretion can therefore be viewed as a two-step process, beginning at pre-ecdysis when cGMP levels are relatively low, followed by a massive release resulting from a logarithmic elevation of cGMP levels.

scholarly journals Fever and immunoregulation. III. Hyperthermia augments the primary in vitro humoral immune response.

1983 ◽  
Vol 157 (4) ◽  
pp. 1229-1238 ◽  
Author(s):  
H D Jampel ◽  
G W Duff ◽  
R K Gershon ◽  
E Atkins ◽  
S K Durum
Keyword(s):  
Immune Response ◽  
Cell Response ◽  
Direct Action ◽  
Interleukin 1 ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Humoral Immune ◽  
Fever Response ◽  
And Function

We have examined the possibility that hyperthermia, such as that occurring during fever, may benefit the immune response. The effect of temperature on the in vitro immune response of unprimed murine spleen cells against the antigen sheep erythrocytes was tested. Hyperthermia potently augmented the plaque-forming cell response. Temperature-sensitive events occurred early in the culture period. Subsets of lymphocytes were independently assessed for effects of temperature on their activation and function. We showed that the beneficial effect of elevated temperature on the plaque-forming cell response probably occurs during the priming stage of T helper cells, and neither improves the delivery of help or the activation of B cells, nor impairs suppressor T cell generation or function. We propose that this powerful immunopotentiating effect of hyperthermia may account for the selective value of the fever response. This suggests taht the monokine interleukin 1, which is the endogenous mediator of fever, may promote immune responses both through a direct action on lymphocytes, and indirectly by an action on the central nervous system resulting in fever.

scholarly journals Deficiency of bone morphogenetic protein-3b induces metabolic syndrome and increases adipogenesis

2020 ◽  
Vol 319 (2) ◽  
pp. E363-E375
Author(s):  
Íngrid Martí-Pàmies ◽  
Robrecht Thoonen ◽  
Patrick Seale ◽  
Alexia Vite ◽  
Alex Caplan ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Bone Morphogenetic Protein ◽  
Endocrine System ◽  
Left Ventricular ◽  
Glucose And Lipid Metabolism ◽  
Age Related ◽  
Morphogenetic Protein ◽  
Lv Remodeling ◽  
And Function

Bone morphogenetic protein (BMP) receptor signaling is critical for the regulation of the endocrine system and cardiovascular structure and function. The objective of this study was to investigate whether Bmp3b, a glycoprotein synthetized and secreted by adipose tissue, is necessary to regulate glucose and lipid metabolism, adipogenesis, and cardiovascular remodeling. Over the course of 4 mo, Bmp3b-knockout ( Bmp3b−/−) mice gained more weight than wild-type (WT) mice. The plasma levels of cholesterol and triglycerides were higher in Bmp3b−/− mice than in WT mice. Bmp3b−/− mice developed insulin resistance and glucose intolerance. The basal heart rate was higher in Bmp3b−/− mice than in WT mice, and echocardiography revealed eccentric remodeling in Bmp3b−/− mice. The expression of adipogenesis-related genes in white adipose tissue was higher in Bmp3b−/− mice than in WT control mice. In vitro studies showed that Bmp3b modulates the activity of the C/ebpα promoter, an effect mediated by Smad2/3. The results of this study suggest that Bmp3b is necessary for the maintenance of homeostasis in terms of age-related weight gain, glucose metabolism, and left ventricular (LV) remodeling and function. Interventions that increase the level or function of BMP3b may decrease cardiovascular risk and pathological cardiac remodeling.

scholarly journals Identification and Function of ETH Receptor Networks in The Silkworm Bombyx Mori

2021 ◽  
Author(s):  
Ivana Daubnerová ◽  
Ladislav Roller ◽  
Honoo Satake ◽  
Chen Zhang ◽  
Young-Joon Kim ◽  
...  
Keyword(s):  
Bombyx Mori ◽  
Expression Patterns ◽  
Temporal Distribution ◽  
Malpighian Tubules ◽  
Corpora Allata ◽  
Careful Examination ◽  
Peripheral Organs ◽  
Inka Cells ◽  
And Function

Abstract Insect ecdysis triggering hormones (ETHs) released from endocrine Inka cells act on specific neurons in the central nervous system (CNS) to activate the ecdysis sequence. These primary target neurons express distinct splicing variants of ETH receptor (ETHR-A or ETHR-B). Here, we characterized both ETHR subtypes in the moth Bombyx mori in vitro and mapped spatial and temporal distribution of their expression within the CNS and peripheral organs. In the CNS, we detected non-overlapping expression patterns of each receptor isoform which showed dramatic changes during metamorphosis. Most ETHR-A and a few ETHR-B neurons produce multiple neuropeptides which are downstream signals for the initiation or termination of various phases during the ecdysis sequence. We also described novel roles of different neuropeptides during these processes. Careful examination of peripheral organs revealed ETHRs expression in specific cells of the frontal ganglion (FG), corpora allata (CA), H-organ and Malpighian tubules prior to each ecdysis. These data indicate that PETH and ETH are multifunctional hormones that act via ETHR-A and ETHR-B to control various functions during the entire development - the ecdysis sequence and associated behaviors by the CNS and FG, JH synthesis by the CA, and possible activity of the H-organ and Malpighian tubules.

scholarly journals Control of insect ecdysis by a positive-feedback endocrine system: roles of eclosion hormone and ecdysis triggering hormone.

1997 ◽  
Vol 200 (5) ◽  
pp. 869-881 ◽  
Author(s):  
J Ewer ◽  
S C Gammie ◽  
J W Truman
Keyword(s):  
Positive Feedback ◽  
Endocrine Cells ◽  
Endocrine System ◽  
Eclosion Hormone ◽  
The Central Nervous System ◽  
Inka Cells ◽  
Ecdysis Triggering Hormone ◽  
Relationship Of ◽  
The Relationship ◽  
Motor Programme

A successful ecdysis in insects requires the precise coordination of behaviour with the developmental changes that occur late in a moult. This coordination involves two sets of endocrine cells: the peripherally located Inka cells, which release ecdysis triggering hormone (ETH), and the centrally located neurosecretory neurones, the VM neurones, which release eclosion hormone (EH). These two sets of endocrine cells mutually excite one another: EH acts on the Inka cells to cause the release of ETH. ETH, in turn, acts on the VM neurones to cause the release of EH. This positive-feedback relationship allows the Inka cells and the VM neurones to be the peripheral and central halves, respectively, of a decision-making circuit. Once conditions for both halves have been satisfied, their reciprocal excitation results in a massive EH/ETH surge in the blood as well as a release of EH within the central nervous system. This phasic signal then causes the tonic activation of a distributed network of peptidergic neurones that contain crustacean cardioactive peptide. The relationship of the latter cells to the subsequent maintenance of the ecdysis motor programme is discussed.

Dual ecdysteroid action on the epitracheal glands and central nervous system preceding ecdysis of Manduca sexta

2001 ◽  
Vol 204 (20) ◽  
pp. 3483-3495 ◽  
Author(s):  
Inka Žitňanová ◽  
Michael E. Adams ◽  
Dušan Žitňan
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Manduca Sexta ◽  
Transcriptional Activity ◽  
Subsequent Treatment ◽  
Dual Action ◽  
The Central Nervous System ◽  
Inka Cells ◽  
Ecdysis Triggering Hormone ◽  
Behavioural Sequence

SUMMARY Initiation of the ecdysis behavioural sequence in insects requires activation of the central nervous system (CNS) by pre-ecdysis-triggering hormone (PETH) and ecdysis-triggering hormone (ETH), which are released from the Inka cells of the epitracheal glands. Here, we show that the developmental events preceding larval and pupal ecdysis of Manduca sexta involve a dual action of ecdysteroids on the epitracheal glands and CNS. The low steroid levels in freshly ecdysed and feeding larvae are associated with small-sized epitracheal glands, reduced peptide production in Inka cells and insensitivity of the CNS to ETH. The elevated ecdysteroid levels before each ecdysis lead to a dramatic enlargement of Inka cells and increased production of peptide hormones and their precursors. As blood ecdysteroids reach peak levels, the CNS becomes responsive to Inka cell peptides. These effects of natural ecdysteroid pulses can be experimentally induced by injection of 20-hydroxyecdysone or the ecdysteroid agonist tebufenozide (RH-5992) into ecdysed larvae, thus stimulating peptide production in Inka cells and inducing CNS sensitivity to ETH. A direct steroid action on the CNS is demonstrated by subsequent treatment of isolated nerve cords from ecdysed larvae with 20-hydroxyecdysone and ETH, which results in pre-ecdysis or ecdysis bursts. Our data show that ecdysteroid-induced transcriptional activity in both the epitracheal glands and the CNS are necessary events for the initiation of the ecdysis behavioural sequence.

scholarly journals Pus3p- and Pus1p-Dependent Pseudouridylation of Steroid Receptor RNA Activator Controls a Functional Switch that Regulates Nuclear Receptor Signaling

2007 ◽  
Vol 21 (3) ◽  
pp. 686-699 ◽  
Author(s):  
Xiansi Zhao ◽  
Jeffrey R. Patton ◽  
Sajal K. Ghosh ◽  
Nathan Fischel-Ghodsian ◽  
Ling Shen ◽  
...  
Keyword(s):  
Steroid Receptor ◽  
Cell Extract ◽  
Dominant Negative ◽  
Transfer Rnas ◽  
Pseudouridine Synthase ◽  
Dominant Negative Activity ◽  
And Function ◽  
Common Target

Abstract It was previously shown that mouse Pus1p (mPus1p), a pseudouridine synthase (PUS) known to modify certain transfer RNAs (tRNAs), can also bind with nuclear receptors (NRs) and function as a coactivator through pseudouridylation and likely activation of an RNA coactivator called steroid receptor RNA activator (SRA). Use of cell extract devoid of human Pus1p activity derived from patients with mitochondrial myopathy and sideroblastic anemia, however, still showed SRA-modifying activity suggesting that other PUS(s) can also target this coactivator. Here, we show that related mPus3p, which has a different tRNA specificity than mPus1p, also serves as a NR coactivator. However, in contrast to mPus1p, it does not stimulate sex steroid receptor activity, which is likely due to lack of binding to this class of NRs. As expected from their tRNA activities, in vitro pseudouridylation assays show that mPus3p and mPus1p modify different positions in SRA, although some may be commonly targeted. Interestingly, the order in which these enzymes modify SRA determines the total number of pseudouridines. mPus3p and SRA are mainly cytoplasmic; however, mPus3p and SRA are also localized in distinct nuclear subcompartments. Finally, we identified an in vivo modified position in SRA, U206, which is likely a common target for both mPus1p and mPus3p. When U206 is mutated to A, SRA becomes hyperpseudouridylated in vitro, and it acquires dominant-negative activity in vivo. Thus, Pus1p- and Pus3p-dependent pseudouridylation of SRA is a highly complex posttranscriptional mechanism that controls a coactivator-corepressor switch in SRA with major consequences for NR signaling.

scholarly journals Identification and function of ETH receptor networks in the silkworm Bombyx mori

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ivana Daubnerová ◽  
Ladislav Roller ◽  
Honoo Satake ◽  
Chen Zhang ◽  
Young-Joon Kim ◽  
...  
Keyword(s):  
Bombyx Mori ◽  
Expression Patterns ◽  
Temporal Distribution ◽  
Malpighian Tubules ◽  
Corpora Allata ◽  
Careful Examination ◽  
Peripheral Organs ◽  
Inka Cells ◽  
And Function

AbstractInsect ecdysis triggering hormones (ETHs) released from endocrine Inka cells act on specific neurons in the central nervous system (CNS) to activate the ecdysis sequence. These primary target neurons express distinct splicing variants of ETH receptor (ETHR-A or ETHR-B). Here, we characterized both ETHR subtypes in the moth Bombyx mori in vitro and mapped spatial and temporal distribution of their expression within the CNS and peripheral organs. In the CNS, we detected non-overlapping expression patterns of each receptor isoform which showed dramatic changes during metamorphosis. Most ETHR-A and a few ETHR-B neurons produce multiple neuropeptides which are downstream signals for the initiation or termination of various phases during the ecdysis sequence. We also described novel roles of different neuropeptides during these processes. Careful examination of peripheral organs revealed ETHRs expression in specific cells of the frontal ganglion (FG), corpora allata (CA), H-organ and Malpighian tubules prior to each ecdysis. These data indicate that PETH and ETH are multifunctional hormones that act via ETHR-A and ETHR-B to control various functions during the entire development—the ecdysis sequence and associated behaviors by the CNS and FG, JH synthesis by the CA, and possible activity of the H-organ and Malpighian tubules.

Molecular architecture and functions of the neuronal cytoskeleton

1990 ◽  
Vol 48 (3) ◽  
pp. 2-3
Author(s):  
Nobutaka Hirokawa
Keyword(s):  
Major Elements ◽  
Molecular Structures ◽  
Organelle Transport ◽  
Molecular Architecture ◽  
Neuronal Morphogenesis ◽  
Microtubule Associated Proteins ◽  
Associated Proteins ◽  
And Function ◽  
Small Clusters

In this symposium I will present our studies about the molecular architecture and function of the cytomatrix of the nerve cells. The nerve cell is a highly polarized cell composed of highly branched dendrites, cell body, and a single long axon along the direction of the impulse propagation. Each part of the neuron takes characteristic shapes for which the cytoskeleton provides the framework. The neuronal cytoskeletons play important roles on neuronal morphogenesis, organelle transport and the synaptic transmission. In the axon neurofilaments (NF) form dense arrays, while microtubules (MT) are arranged as small clusters among the NFs. On the other hand, MTs are distributed uniformly, whereas NFs tend to run solitarily or form small fascicles in the dendrites Quick freeze deep etch electron microscopy revealed various kinds of strands among MTs, NFs and membranous organelles (MO). These structures form major elements of the cytomatrix in the neuron. To investigate molecular nature and function of these filaments first we studied molecular structures of microtubule associated proteins (MAP1A, MAP1B, MAP2, MAP2C and tau), and microtubules reconstituted from MAPs and tubulin in vitro. These MAPs were all fibrous molecules with different length and formed arm like projections from the microtubule surface.

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