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PubMed1995

A highly conserved red pigment-concentrating hormone precursor in the blue crab Callinectes sapidus.

A cDNA library was established from the eyestalk ganglia of the blue crab Callinectes sapidus. One clone was isolated (644 bp excluding the poly(A) tail) which encodes the red pigment-concentrating hormone (RPCH)-precursor, consisting of the 25 amino acid residue signal peptide, the RPCH, and a 73 amino acid residue RPCH-precursor related peptide. This clone displays high sequence similarity with a clone isolated from an eyestalk cDNA library of the shore crab Carcinus maenas, in accordance with the close phylogenetic relationship between these species. Northern blot experiments indicated the presence of two different mRNA transcripts which hybridized with a specific RPCH-cDNA probe pointing to the possibility of multiple RPCH isoforms in the blue crab. Although crustacean RPCH and the insect adipokinetic hormones (AKH) are structurally related, their precursors show little similarity.

Amino Acid Sequence↗
PubMed1986

Isolation and primary structure of a peptide from the corpora cardiaca of Heliothis zea with adipokinetic activity.

An adipokinetic hormone was isolated from the corpora cardiaca of the corn ear worm moth, Heliothis zea, and purified by reversed phase high performance liquid chromatography. The primary structure, pGlu-Leu-Thr-Phe-Thr-Ser-Ser-Trp-Gly-NH2, was determined by automated gas-phase Edman degradation of the peptide deblocked with pyroglutamic aminopeptidase, and by fast atom bombardment mass spectrometry. The hormone was synthesized and the natural and synthetic material had identical chromatographic, spectroscopic, and biological properties. The peptide was found to have lipid mobilizing activity in H. zea adults.

Amino Acid Sequence↗
PubMed1989

Developmental changes in phosphodiesterase activity and hormonal response in the prothoracic glands of Manduca sexta.

Prothoracicotropic hormone (PTTH) stimulates ecdysteroid secretion by the prothoracic glands of Manduca sexta in a cAMP-dependent manner. However, larval and pupal glands differ markedly in the degree to which PTTH stimulates cAMP accumulation, suggesting a stage-specific difference in phosphodiesterase activity. The present study was designed to determine if and when such a difference arose during development, and its effect on PTTH-stimulated ecdysteroid secretion. The results reveal that soluble phosphodiesterase activity in the prothoracic glands changes significantly during the course of the fifth (last) larval instar, with a marked increase in activity occurring at the onset of prepupal development. Phosphodiesterase activity, particularly in the soluble cell fraction, is inversely correlated with PTTH-stimulated cAMP accumulation. Hormone-stimulated ecdysteroid secretion does not require cAMP accumulation, but does appear to require detectable cAMP synthesis as measured in the presence of phosphodiesterase inhibitors. The amount of ecdysteroid secreted, however, is not proportional to the amount of cAMP synthesized but rather is more closely correlated with developmental changes in glandular protein content.

Animals↗
PubMed1994

Ca2+ currents in cockroach neurones: properties and modulation by neurohormone D.

In dorsal unpaired median (DUM) neurones isolated from the terminal ganglion of the cockroach Periplaneta americana two types of Ca2+ currents were found: a transient one activated by lower depolarizations (LVA) and a sustained one activated by higher voltage jumps (HVA). Both currents were strongly reduced by 100 microM Cd2+; Ni2+ was less effective. The HVA currents were insensitive to dihydropyridines, but sensitive to phenylalkylamines. The LVA component was sensitive to omega-conotoxin GVIA and SK&F96365 whereas the HVA component was insensitive to both blockers. The octapeptide neurohormone D (NHD), a member of the family of adipokinetic hormones (AKH-peptides), is known to increase the spiking frequence in these DUM cells. We demonstrate that NHD increases the LVA current component and decreases the HVA current component. These effects of NHD can explain the previously found NHD-induced stimulation of Ca2+ dependent K+ currents.

Animals↗
PubMed1996

Molecular sequencing and modeling of Neobellieria bullata trypsin. Evidence for translational control by Neobellieria trypsin-modulating oostatic factor.

Trypsin mRNA from the grey fleshfly (Neobellieria bullata) was reversed transcribed and amplified by means of PCR. Two cDNA species of 600 bp and 800 bp were cloned and sequenced. The 3' end of the gene (300 bp) was amplified by means of the rapid-amplification-of-cDNA-ends method, cloned and sequenced. The deduced protein sequence of 254 amino acids exhibited 46% identity to Drosophila trypsin and 32% identity to Anophiline trypsin and Aedes trypsin. Three-dimensional models of Neobellieria trypsin and Drosophilia trypsin were built and compared. Both models contain two domains of beta-barrel sheets as was shown by means of X-ray crystallography of mammalian trypsin. The catalytic active site is composed of the canonical triad of His42, Asp87 and Ser182 whereas Asp176 sits as the bottom of the specificity pocket. Southern blot analysis suggested that Neobellieria trypsin is encoded by one gene. Northern blot analysis showed that an early trypsin transcript is found in the midgut of sugar-fed females. This message disappeared after a liver meal, and was replaced by a late transcript. Injection of trypsin-modulating oostatic factor (TMOF) at 10(-9) M prevented the disappearance and the translation of the early transcript. TMOF did not prevent the appearance of the late transcript. However, in the presence of the hormone the late transcript was not translated. Thus, TMOF is the biological signal that terminates the translation of trypsin mRNA in the fleshfly gut and probably in the mosquito gut.

Amino Acid Sequence↗
PubMedDate not supplied

Partial purification of a receptor for the adipokinetic hormones from Musca autumnalis face flies.

Partial purification of the receptors for the neurohormones, diptera corpora cardiaca factors 1 and 2 (DCC1 and DCC2) was achieved. Receptor proteins were obtained from the abdomens of face fly, Musca autumnalis De Geer. Purification methods included detergent solubilization, affinity chromatography, and polyacrylamide gel electrophoresis. Analysis by gel electrophoresis has identified two proteins from this partial purification with relative molecular weights of 45 and 90 kD. A crude receptor preparation was used to develop a ligand binding assay with radiolabeled (tritiated and iodinated) DCC1. Ligand binding was inhibited by 90% when excess unlabeled DCC1 was added to the assay mixture. Ligand binding was optimum at pH 7.5. Binding saturation occurred at approximately 12 picomole radiolabeled ligand concentration. Because DCC1 and DCC2 have been shown to effect the lipid and trehalose levels in the insect an understanding of the neuropeptide-receptor interaction is important for the development of new methods of control of dairy and poultry muscoid flies.

Animals↗
PubMed2004

Comparative larvicidal toxicities of three ecdysone agonists on the mosquitoes Aedes aegypti, Culex quinquefasciatus, and Anopheles gambiae.

Ecdysone agonists are hormonally active insect growth regulators that disrupt development of pest insects and have potential for development as insecticides. Their effects have been particularly well-studied in Lepidoptera and Coleoptera, but significantly less is known about their effects on dipterans, particularly aquatic species. The potency of three ecdysone agonists on larvae of 3 mosquito species, Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus, was examined. Anopheles gambiae was the most susceptible species and Ae. aegypti was the most resistant species to the effects of the three compounds tested. Potency, in descending order, was RH-2485 > RH-5992 > RH-5849. Dose-response relationships were determined for the three agonists; RH-2485 was found to be the most effective endocrine disruptor against all three species. The observed biological effects of these compounds were similar to those reported for other insects, and mosquitoes initiated molting and apolysis but did not complete a molt. In some cases, mosquito larvae synthesized a new cuticle that appeared to be normally sclerotized but the larvae failed to ecdyse and shed the exuvium. These compounds may prove to be valuable insect growth regulators for control of mosquitoes to decrease the frequency of pathogen transmission to humans. Prospects for using these compounds to control mosquitoes in the field are discussed, along with possible impacts on non-target arthropods in mosquito habitats.

Animals↗
PubMed1996

Cell cycle parameters in Aedes albopictus mosquito cells.

We have analyzed cell cycle parameters for the Aedes albopictus C7-10 mosquito cell line, which has been systematically developed for somatic cell genetics, expression of transfected genes, and synthesis of hormone-inducible proteins. In rapidly cycling cells, we measured a generation time of 10-12 h. The duration of mitosis (M) was < or = 1 h, and the DNA synthesis phase (S) required 6 h. Unlike Drosophila melanogaster Kc cells, in which the G2 gap is substantially longer than G1, in C7-10 cells G1 and G2 each lasted approximately 2 h. In these cells, the duration of both S and G2 was independent of the population doubling time, and the increase in population doubling time as cells approached confluency was due to prolongation of G1. When treated with the insect steroid hormone, 20-hydroxyecdysone, C7-10 mosquito cells complete the cycle in progress before undergoing a reversible arrest.

Aedes↗
PubMed1986

Identification and initial characterization of adipokinetic hormone-like immunoreactive peptides of rat origin.

An antiserum was raised to adipokinetic hormone (AKH), a 10-amino-acid-residue peptide found in the arthropod Locusta migratoria. The antiserum demonstrated not only immunocytochemical reaction with some other arthropod species, but also stained many areas of the rat CNS, certain islet cells of the pancreas, and some anterior pituitary cells. The pattern of staining was unlike that for any known rat neuropeptide or hormone. With the antiserum used as the detection system, HPLC and high-voltage electrophoresis yielded two peptides that were purified to homogeneity from rat hypothalamic median eminence. These peptides have unique amino acid compositions, indicating they may be heretofore unknown rat neuropeptides.

Animals↗
PubMed2004

Effects of an herbal medication containing bee products on menopausal symptoms and cardiovascular risk markers: results of a pilot open-uncontrolled trial.

OBJECTIVES: Fifty-five postmenopausal women with menopausal complaints were treated with the food supplement Melbrosia for 3 months. Menopausal symptom evaluation scales and psychological questionnaires were administered, and cardiovascular disease markers in blood were analyzed at the beginning and the end of the trial. SETTING: The perimenopausal care unit of Second Obstetrics and Gynecology Hospital, Sofia, Bulgaria. DESIGN: The study was an open, multicenter, uncontrolled, prospective observation study. The subjective symptoms questionnaires administered before Melbrosia treatment and after 3 months of treatment were Kupperman Score, Zerssen Symptom List, Zung Depression Score, and Frankfurt Self-concept Scale (self-assessment test, problem-solving test, self-esteem test, and irritability test). The blood levels of high-density lipoproteins (HDL), low-density lipoproteins (LDL), triglycerides (TG), total cholesterol (TC), vascular cell adhesion molecule-1 (VCAM-1), and C-reactive protein (CRP) levels were measured in a subgroup of patients. RESULTS: Treatment of postmenopausal women with Melbrosia led to a statistically significant reduction in the Kupperman score, Zerssen's Symptoms List, and Zung Depression Score. The Frankfurt Self-concept Scale revealed significant improvement in problem-solving, no change in self-assessment and self-esteem, and worsening of irritability. Treatment with Melbrosia significantly reduced TC and LDL and significantly elevated HDL and TG. There were nonsignificant changes of serum VCAM-1 and CRP levels in patients treated with Melbrosia. CONCLUSIONS: The presented data suggest that Melbrosia may offer a potential alternative to hormone therapy for the treatment of menopausal symptoms. However, because of this study's uncontrolled, open- label methodology, no cause-and-effect inferences can be drawn until a larger, longer-term, blinded, placebo-controlled, randomized clinical trial is performed.

Adult↗
PubMed1988

The EGPs: the eclosion hormone and cyclic GMP-regulated phosphoproteins. I. Appearance and partial characterization in the CNS of Manduca sexta.

The present study describes 2 phosphoproteins, both with an apparent molecular weight of 54 kDa, in the CNS of the tobacco hornworm, Manduca sexta. Their phosphorylation is regulated by a neuropeptide, eclosion hormone (EH), and the second messenger cGMP, which thus have been named the EGPs (eclosion hormone- and cGMP-regulated phosphoproteins). Although cAMP was more effective than cGMP at stimulating the phosphorylation of the EGPs in CNS homogenates, in the intact CNS cGMP was more effective. Since cGMP mediates the action of EH, this strongly suggests that cGMP is the second messenger that stimulates the phosphorylation of the EGPs in vivo. The EGPs can only be phosphorylated in vitro during discrete time periods during the life of Manduca. During the larval and pupal molts, the EGPs can first be phosphorylated just prior to ecdysis. Their ability to be phosphorylated is correlated with the time when the insect is sensitive to EH. This close temporal correlation suggests that the ability to phosphorylate the EGPs determines when the insect can first respond to EH. During adult development, the EGPs first appeared on fluorograms 6 d before sensitivity to EH, suggesting that at this stage other factors may also be involved in the regulation of sensitivity. For the ecdyses of all 3 stages, EH appeared to stimulate the phosphorylation of the EGPs at ecdysis. The EGPs were found in all regions of the prepupal nervous system that were investigated, but only in the abdominal and pterothoracic ganglia of the developing adult. Fractionation of nervous system homogenates by ultracentrifugation revealed that one of the EGPs was present only in the pellet fraction, whereas the other was approximately equally distributed between pellet and supernatant. Furthermore, the EGPs in the pellet fraction could be partially solubilized with detergents and high salt concentrations.

Animals↗
PubMed1987

Identification of an arginine vasopressin-like diuretic hormone from Locusta migratoria.

We have identified two neuropeptides (F1 and F2) from suboesophageal and thoracic ganglia of Locusta migratoria, which we isolated earlier based on their immunological similarity to arginine vasopressin. The more abundant and hydrophilic factor, F1, has sequence Cys-Leu-Ile-Thr-Asn-Cys-Pro-Arg-Gly-NH2, but its biological role is unknown. The less abundant factor, F2, is an antiparallel dimer of F1, and functions as a diuretic hormone of this species. It appears to act through the intermediacy of cyclic AMP. The properties of the native neuropeptides were identical with those of samples synthesized from appropriately protected L-amino acids.

Amino Acid Sequence↗
PubMed2002

Restriction of nutrient intake results in the increase of a specific Manduca sexta allatotropin (Manse-AT) mRNA in the larval nerve cord.

The Manduca allatotropin (Manse-AT) gene is expressed as three mRNAs that differ from each other by alternative splicing. The level of one of these mRNAs (RNA-3) is specifically increased in the nerve cord of last instar larvae that were starved, parasitized, or fed the ecdysteroid agonist RH-5992. Each of these treatments results in reduction of feeding and increased levels of juvenile hormone (JH). The normal decline in JH biosynthesis by the corpora allata does not occur in starved or RH-5992-fed larvae. The increase in RNA-3 levels has the capacity to increase the production of Manse-AT and two related peptides that may be part of the complex response of larvae to nutrient deprivation.

Alternative Splicing↗
PubMed1986

CL-proteins and the regulation of lipoprotein lipase activity in locust flight muscle.

Lipoprotein lipases in the flight muscles of Locusta migratoria show a marked substrate specificity: diacylglycerols associated with the adipokinetic hormone (AKH)-induced lipoprotein, A+, are hydrolysed at 4 to 5 times the rate of those associated with the lipoprotein in resting (non-hormone-stimulated) locusts, Ayellow. To determine the basis for this discrimination, the effect on the activity of flight muscle lipoprotein lipase of CL-proteins, a major constituent of lipoprotein A+, but not of Ayellow, has been investigated; they inhibit the flight muscle enzyme in a competitive manner whether activity is measured with a natural lipoprotein substrate, a lipid emulsion or a water soluble substrate. Experiments in vivo suggest that the flight muscle enzyme is normally inhibited in resting (non-AKH-stimulated) locusts but, interestingly, injection of synthetic AKH-I relieves the inhibition and increases the activity by 30 to 40%. This is not a direct effect of the hormone on the enzyme, but appears to be related to the hormone-induced formation of lipoprotein A+, so that the majority of CL-proteins in the haemolymph become bound to this lipoprotein and the concentration of free CL-proteins is markedly reduced. We suggest that CL-proteins play a major role in the regulation of lipoprotein lipase in locust flight muscle.

Animals↗
PubMed1992

Characterization of the precursor for Manduca sexta diuretic hormone Mas-DH.

We have isolated a cDNA clone encoding a precursor form of the diuretic hormone from the tobacco hornworm Manduca sexta (Mas-DH). Translation of the cDNA revealed a 138-amino acid precursor consisting of the Mas-DH amino acid sequence bounded by dibasic amino acid processing sites, a putative signal sequence, and additional peptide sequence on either side of the Mas-DH coding sequence. The region of the precursor upstream of the mature Mas-DH sequence shows limited (28%) homology to the cryptic region of the ovine corticotropin-releasing factor precursor. The Mas-DH RNA is 1.5-1.6 kilobases long; it is present in both the heads and bodies of adult and larval insects. In prewandering fifth stadium larvae, Mas-DH mRNA is expressed in brain, nerve cord, gut, and Malpighian tubules, but not in the fat body. There is a single genomic copy of the Mas-DH gene; the message is multiply spliced.

Amino Acid Sequence↗
PubMed1994

Protein synthesis and ecdysteroidogenesis in prothoracic glands of the tobacco hornworm (Manduca sexta): stimulation by big prothoracicotropic hormone.

The 28-kDa size variant of prothoracicotropic hormone (big PTTH) stimulates ecdysteroidogenesis by prothoracic glands of Manduca sexta. In the present studies, big PTTH stimulated in vitro incorporation of [35S]methionine into proteins of prothoracic glands from Day 7 last instar larvae. In 2-hr incubations, big PTTH elicited an approximately 2-fold increase in total protein-specific activity. The effect appeared to be tissue specific, as big PTTH had no effect on incorporation of label into proteins of control tissue (fat body). Electrophoretic separation of tissue homogenates, followed by autoradiography and densitometric analysis, revealed increased incorporation of radiolabel into numerous glandular proteins. The result suggested that the effect of big PTTH was a general stimulation of protein synthesis, not specific stimulation of a subset of glandular proteins. Big PTTH-stimulated ecdysteroidogenesis was inhibited by cycloheximide, indicating that the increase in protein synthesis is a requisite for enhanced hormone production. Analysis of gland incubation media revealed numerous radiolabeled proteins. The effect of big PTTH on incorporation of [35S]methionine into media proteins was considerably more variable than the effect of big PTTH on tissue incorporation. The result is consistent with the hypothesis that prothoracic glands may release proteins in addition to ecdysteroids.

Animals↗
PubMed1991

A unique charged tyrosine-containing member of the adipokinetic hormone/red-pigment-concentrating hormone peptide family isolated and sequenced from two beetle species.

An identical neuropeptide was isolated from the corpora cardiaca of two beetle species, Melolontha melolontha and Geotrupes stercorosus. Its primary structure was determined by pulsed-liquid-phase sequencing employing Edman chemistry after enzymically deblocking the N-terminal pyroglutamate residue. The C-terminus was also blocked, as indicated by the lack of digestion when the peptide was incubated with carboxypeptidase A. The sequence of this peptide, which is designated Mem-CC, is pGlu-Leu-Asn-Tyr-Ser-Pro-Asp-Trp-NH2. It is a new member of the adipokinetic hormone/red-pigment-concentrating hormone (AKH/RPCH) family of peptides with two unusual structural features: it is charged and contains a tyrosine residue at position 4, where all other family members have a phenylalanine residue. Structure-activity studies in the migratory locust (Locusta migratoria) and the American cockroach (Periplaneta americana) revealed that the peptide was poorly active, owing to its structural uniqueness.

Amino Acid Sequence↗