Mode of Action of the Hypertrehalosaemic Peptides from the American Cockroach

1985 ◽  
Vol 40 (9-10) ◽  
pp. 670-676 ◽  
Author(s):  
Gerd Gäde
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Mode Of Action ◽  
Glycogen Phosphorylase ◽  
Fat Body ◽  
American Cockroach ◽  
Dependent Manner ◽  
Low Concentrations ◽  
First Time ◽  
Dose Dependent

Abstract Although crude extracts of cockroach (Periplaneta amencana) corpora cardiaca have been shown previously to affect the activity of adenylate cyclase and phosphorylase, we demonstrate in the present study for the first time that low concentrations (0.5 to 5 pmol) of the synthetic myoactive peptides. M I and M II, also affect these systems; these myoactive peptides are identical to the hypertrehalosaemic hormones I and II, and cause an increase in the concentration of the second messenger cyclic AMP in the fat body.In addition, both octapeptides activate fat body glycogen phosphorylase and promote breakdown of fat body glycogen. Both peptides increase the levels to haemolymph carbohydrate in a dose-dependent manner.

scholarly journals Changes in adenosine receptors during differentiation of 3T3-F442A cells to adipocytes

1988 ◽  
Vol 249 (2) ◽  
pp. 377-381 ◽  
Author(s):  
K Ravid ◽  
J M Lowenstein
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Adenosine Receptors ◽  
Positive Response ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Similar Extent ◽  
Phenylisopropyl Adenosine ◽  
Dose Dependent ◽  
Basal Concentration

Incubation of undifferentiated 3T3-F442A cells (preadipocytes) with 5′-N-ethylcarboxamidoadenosine (NECA) increases intracellular cyclic AMP in a dose-dependent manner. The effect of NECA is antagonized by 8-phenyltheophylline, but potentiated by 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidine, an inhibitor of cyclic AMP phosphodiesterase. Incubation of preadipocytes with (-)-N6-(R-phenylisopropyl)adenosine (PIA) has no inhibitory effect on the basal concentration of cyclic AMP or on the stimulation of adenylate cyclase by isoprenaline or forskolin. Micromolar concentrations of PIA increase intracellular cyclic AMP, but with a lower potency than NECA. Similar findings are obtained with the non-differentiating cell line 3T3-C2. Thus preadipocyte 3T3-F442A cells and 3T3-C2 cells appear to express only stimulatory adenosine receptors. For some time after 3T3-F442A cells have differentiated to adipocytes, micromolar concentrations of NECA and PIA continue to increase cyclic AMP to a similar extent to that in preadipocytes, whereas nanomolar concentrations of PIA decrease the stimulatory effects of isoprenaline and forskolin on adenylate cyclase by 50%. However, several days after differentiation, the adipocytes gradually lose the major part of their positive response to NECA and reach a steady response to NECA 10 days after differentiation. The inhibition of adenylate cyclase caused by PIA remains constant for at least 2 weeks after differentiation. With membranes derived from the cells, the effects of NECA and PIA depend on GTP. These results indicate that, during the differentiation of 3T3-F442A cells to adipocytes, new inhibitory adenosine receptors are expressed, whereas the stimulatory receptors become attenuated.

Octopamine-mediated elevation of cyclic AMP in haemocytes of the American cockroach, Periplaneta americana L.

1987 ◽  
Vol 65 (6) ◽  
pp. 1509-1514 ◽  
Author(s):  
J. W. D. Gole ◽  
G. L. Orr ◽  
R. G. H. Downer
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Adult Male ◽  
Periplaneta Americana ◽  
American Cockroach ◽  
Time Dependent ◽  
Blocking Agents ◽  
Adrenergic Blocking ◽  
Camp Levels ◽  
Dose Dependent

The injection of 10 μL of 5 × 10−3 M octopamine into the haemocoel of adult male Periplaneta americana results in a 20 × increase in haemolymph cyclic AMP (cAMP) levels within 3 min. Synephrine also causes a marked increase in haemolymph cAMP, and less pronounced elevations were obtained following the injection of tyramine, dopamine, norepinephrine, 5-hydroxytryptamine, phenylethanolamine, β-phenylethylamine, and L-phenylephrine. The octopamine effect is time dependent for at least 10 min and dose dependent with the EC50 for the injected dose calculated to be about 2.5 × 10−3 M. These results indicate that the octopamine response is receptor mediated and studies on isolated haemocytes suggest that the octopamine-sensitive receptors are located on haemocytes. Incubation of whole haemocytes in medium containing octopamine results in a dose-dependent elevation of cAMP with the EC50 calculated at about 7.5 × 10−6 M. Synephrine, tyramine, and dopamine also elevate cAMP levels in incubated haemocytes, and the activator of adenylate cyclase, forskolin, causes a marked increase in cAMP. The octopamine-mediated response is blocked by mianserin, phentolamine, and cyproheptadine but not by the β-adrenergic blocking agents propranolol and dichloroisoproterenol.

On the release and action of the hypertrehalosaemic hormone from the cockroach nauphoeta cinerea

1988 ◽  
Vol 43 (1-2) ◽  
pp. 108-116 ◽  
Author(s):  
Gerd Gäde
Keyword(s):  
Glycogen Phosphorylase ◽  
Periplaneta Americana ◽  
Fat Body ◽  
Neurosecretory Cells ◽  
American Cockroach ◽  
Corpora Cardiaca ◽  
Nauphoeta Cinerea ◽  
Dose Dependent Fashion ◽  
Dose Dependent

The corpora cardiaca of the cockroach Nauphoeta cinerea contain a hypertrehalosaemic hormone (HTH) which is chemically characterized as a blocked decapeptide. The synthetic HTH shows the same chromatographic behaviour as the material isolated from corpora cardiaca. The synthetic peptide causes hypertrehalosaemia and fat body glycogen phosphorylase-activation in N. cinerea as well as in the American cockroach, Periplaneta americana in a dose-dependent fashion. It is calculated that one gland from N. cinerea stores about 50 pmol of HTH. Roughly 10% of the total available hormone in the gland is released in vitro during exposure to an elevated potassium saline which causes depolarization of the neurosecretory cells

Effects of ethanol on gastric epithelial cell phospholipid dynamics and cellular function

1987 ◽  
Vol 252 (2) ◽  
pp. G237-G243
Author(s):  
R. E. Bailey ◽  
R. A. Levine ◽  
J. Nandi ◽  
E. H. Schwartzel ◽  
D. H. Beach ◽  
...  
Keyword(s):  
Membrane Structure ◽  
Lipid Membrane ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Dependent Manner ◽  
Chloride Uptake ◽  
Peak Intensity ◽  
Low Concentrations ◽  
Resonance Band ◽  
Dose Dependent

The lipid profile of isolated gastric superficial epithelial cells (SEC) was evaluated by proton nuclear magnetic resonance spectroscopy (1H-NMR). The most conspicuous resonance band in SEC spectra was due to the protons of +N(CH3)3 groups of phosphatidylcholine and, to a lesser degree, other phospholipid derivatives, on the basis of their chemical shift and addition of purified phospholipids. NMR of cell lysates and phospholipid extracts of SEC in deutero-chloroform provided further spectral resolution of these components. Phospholipase or ethanol treatments of SEC produced membrane disorganization reflected as increased peak intensity of the phospholipid signals. In addition, ethanol, in a dose-dependent manner, attenuated paranitrophenyl phosphatase activity, which correlated with inhibition of total and ouabain-sensitive 86Rubidium chloride uptake by SEC. This study suggests that NMR used in conjunction with other biochemical techniques can monitor SEC membrane structure-function relationships. NMR is a potentially powerful noninvasive probe to show changes in lipid membrane organization induced by low concentrations of ethanol (1%) and may indicate an early sign of "cytotoxicity" in intact SEC.

Mutant analysis suggests that cyclic GMP mediates the cyclic AMP-induced Ca2+ uptake in Dictyostelium

1991 ◽  
Vol 99 (1) ◽  
pp. 187-191
Author(s):  
S. Menz ◽  
J. Bumann ◽  
E. Jaworski ◽  
D. Malchow
Keyword(s):  
Cyclic Amp ◽  
Mutant Strain ◽  
Cyclic Gmp ◽  
Parental Strain ◽  
Dependent Manner ◽  
Heavy Chains ◽  
Signal Relay ◽  
Sensitive Electrode ◽  
Dose Dependent ◽  
Cyclic Amp Synthesis

Previous work has shown that streamer F (stmF) mutants of Dictyostelium discoideum exhibit prolonged chemotactic elongation in aggregation fields. The mutants carry an altered structural gene for cyclic GMP phosphodiesterase resulting in low activities of this enzyme. Chemotactic stimulation by cyclic AMP causes a rapid transient increase in the cyclic GMP concentration followed by association of myosin heavy chains with the cytoskeleton. Both events persist several times longer in stmF mutants than in the parental strain, indicating that the change in association of myosin with the cytoskeleton is transmitted directly or indirectly by cyclic GMP. We measured the cyclic AMP-induced Ca2+ uptake with a Ca(2+)-sensitive electrode and found that Ca2+ uptake was prolonged in stmF mutants but not in the parental strain. The G alpha 2 mutant strain HC33 (fgdA), devoid of InsP3 release and receptor/guanylate cyclase coupling, lacked Ca2+ uptake. However, the latter response and cyclic GMP formation were normal in the signal-relay mutant strain agip 53 where cyclic AMP-stimulated cyclic AMP synthesis is absent. LiCl, which inhibits InsP3 formation in Dictyostelium, blocked Ca2+ uptake in a dose-dependent manner. The data indicate that the receptor-mediated Ca2+ uptake depends on the InsP3 pathway and is regulated by cyclic GMP. The rate of Ca2+ uptake was correlated in time with the association of myosin with the cytoskeleton, suggesting that Ca2+ uptake is involved in the motility response of the cells.

scholarly journals Cannabidiol Modulates Mitochondrial Redox and Dynamics in MCF7 Cancer Cells: A Study Using Fluorescence Lifetime Imaging Microscopy of NAD(P)H

2021 ◽  
Vol 8 ◽  
Author(s):  
Rhys Richard Mould ◽  
Stanley W. Botchway ◽  
James R. C. Parkinson ◽  
Elizabeth Louise Thomas ◽  
Geoffrey W Guy ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Fluorescence Lifetime ◽  
Mitochondrial Function ◽  
Mode Of Action ◽  
Fluorescence Lifetime Imaging Microscopy ◽  
Mitochondrial Morphology ◽  
Fluorescence Lifetime Imaging ◽  
Dependent Manner ◽  
Lifetime Imaging ◽  
Dose Dependent

The cannabinoid, cannabidiol (CBD), is part of the plant's natural defense system that when given to animals has many useful medicinal properties, including activity against cancer cells, modulation of the immune system, and efficacy in epilepsy. Although there is no consensus on its precise mode of action as it affects many cellular targets, CBD does appear to influence mitochondrial function. This would suggest that there is a cross-kingdom ability to modulate stress resistance systems that enhance homeostasis. As NAD(P)H autofluorescence can be used as both a metabolic sensor and mitochondrial imaging modality, we assessed the potential of this technique to study the in vitro effects of CBD using 2-photon excitation and fluorescence lifetime imaging microscopy (2P-FLIM) of NAD(P)H against more traditional markers of mitochondrial morphology and cellular stress in MCF7 breast cancer cells. 2P-FLIM analysis revealed that the addition of CBD induced a dose-dependent decrease in bound NAD(P)H, with 20 µM treatments significantly decreased the contribution of bound NAD(P)H by 14.6% relative to the control (p < 0.001). CBD also increased mitochondrial concentrations of reactive oxygen species (ROS) (160 ± 53 vs. 97.6 ± 4.8%, 20 µM CBD vs. control, respectively, p < 0.001) and Ca2+ (187 ± 78 vs. 105 ± 10%, 20 µM CBD vs. the control, respectively, p < 0.001); this was associated with a significantly decreased mitochondrial branch length and increased fission. These are all suggestive of mitochondrial stress. Our results support the use of NAD(P)H autofluorescence as an investigative tool and provide further evidence that CBD can modulate mitochondrial function and morphology in a dose-dependent manner, with clear evidence of it inducing oxidative stress at higher concentrations. This continues to support emerging data in the literature and may provide further insight into its overall mode of action, not only in cancer, but potentially its function in the plant and why it can act as a medicine.

scholarly journals Adrenaline Stimulation of Phospholipid Metabolism in Adipocyte Ghosts

1987 ◽  
Vol 40 (4) ◽  
pp. 405
Author(s):  
David Mann ◽  
Audrey M Bersten
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Linoleic Acid ◽  
Adenylate Cyclase ◽  
Phospholipid Metabolism ◽  
Dependent Manner ◽  
Long Chain Fatty Acids ◽  
Membrane Phospholipids ◽  
Dose Dependent ◽  
Stimulation Of

The incorporation of long-chain fatty acids into phospholipids has been detected in adipocyte ghosts that were incubated with [1_14 C] stearic, [1_14 C] linoleic or [l_14C] arachidonic acid. Adrenaline and adenosine activated this incorporation within 15 s of exposure of the ghosts to the hormones and the response was dose dependent. Maximum incorporation of labelled linoleic acid occurred at 10-5 M adrenaline and 10-7 M adenosine. The a-agonist phenylephrine and the ~-agonist isoproterenol were also shown to stimulate the incorporation of fatty acid in a dose dependent manner. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol were each labelled preferentially with linoleic or arachidonic acid. p-Bromophenacylbromide, quinacrine and centrophenoxine inhibited the adrenaline-stimulated incorporation of fatty acids into ghost membrane phospholipids, and p-bromophenacylbromide also reduced the activation of adenylate cyclase by adrenaline. NaF, an activator of adenylate cyclase, like adrenaline, stimulated the incorporation of linoleic acid into ghost membrane phospholipids.

scholarly journals The Influence of Bee Venom Melittin on the Functioning of the Immune System and the Contractile Activity of the Insect Heart—A Preliminary Study

Toxins ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 494 ◽  
Author(s):  
Jan Lubawy ◽  
Arkadiusz Urbański ◽  
Lucyna Mrówczyńska ◽  
Eliza Matuszewska ◽  
Agata Światły-Błaszkiewicz ◽  
...  
Keyword(s):  
Immune System ◽  
Contractile Activity ◽  
Model Organism ◽  
Dependent Manner ◽  
Physiological Studies ◽  
Almost All ◽  
First Time ◽  
Dose Dependent ◽  
Positive Effect

Melittin (MEL) is a basic polypeptide originally purified from honeybee venom. MEL exhibits a broad spectrum of biological activity. However, almost all studies on MEL activity have been carried out on vertebrate models or cell lines. Recently, due to cheap breeding and the possibility of extrapolating the results of the research to vertebrates, insects have been used for various bioassays and comparative physiological studies. For these reasons, it is valuable to examine the influence of melittin on insect physiology. Here, for the first time, we report the immunotropic and cardiotropic effects of melittin on the beetle Tenebrio molitor as a model insect. After melittin injection at 10−7 M and 10−3 M, the number of apoptotic cells in the haemolymph increased in a dose-dependent manner. The pro-apoptotic action of MEL was likely compensated by increasing the total number of haemocytes. However, the injection of MEL did not cause any changes in the percent of phagocytic haemocytes or in the phenoloxidase activity. In an in vitro bioassay with a semi-isolated Tenebrio heart, MEL induced a slight chronotropic-positive effect only at a higher concentration (10−4 M). Preliminary results indicated that melittin exerts pleiotropic effects on the functioning of the immune system and the endogenous contractile activity of the heart. Some of the induced responses in T. molitor resemble the reactions observed in vertebrate models. Therefore, the T. molitor beetle may be a convenient invertebrate model organism for comparative physiological studies and for the identification of new properties and mechanisms of action of melittin and related compounds.

Biochemical parameters regulating forward motility initiation in vitro in goat immature epididymal spermatozoa

1998 ◽  
Vol 10 (4) ◽  
pp. 299 ◽  
Author(s):  
Bijay S. Jaiswal ◽  
Gopal C. Majumder
Keyword(s):  
Cyclic Amp ◽  
Sperm Motility ◽  
Biochemical Parameters ◽  
Vital Role ◽  
Dependent Manner ◽  
Alkaline Ph ◽  
Heat Stable ◽  
Heat Stable Protein ◽  
Dose Dependent

An investigation was carried out to analyse the biochemical parameters influencing forward motility (FM) initiation in vitro in the goat caput-epididymal immature spermatozoa. Forward motility was induced in approximately 55% of caput-sperm upon incubation in an alkaline (pH 8.0) modified Ringer’s solution containing theophylline (30 mM) (an inhibitor of cyclic AMP phosphodiesterase), dialysed epi-didymal plasma (EP) and bicarbonate. Both EP and bicarbonate induced sperm motility in a dose-dependent manner, and at saturating doses EP (0.6 mg protein mL–1) and bicarbonate (25 mM) induced FM in approx-imately 38% and 44% of the cells, respectively. The motility-promoting efficacy of EP was attributed to a heat-stable protein termed ‘forward motility protein’ (FMP). Bicarbonate served as an initiator as well as a stabilizer of FM and its action was not dependent on FMP. FMP can induce FM in the caput-sperm, but it is not essential for sperm motility initiation. Alteration of the medium pH from 6.60 to 8.00 caused a marked increase in the EP or bicarbonate-dependent sperm FM initiation, as well as intrasperm pH. At the physio-logical pH, bicarbonate served as a much more potent motility activator than FMP, although both the motility promoters showed maximal efficacy at alkaline pH (~7.8). EP as well as bicarbonate elevated the intrasperm cyclic AMP level. Unlike EP, bicarbonate is capable of increasing intrasperm pH. The intrasperm pH increased from 6.54 0.02 to 6.77 0.03 during sperm transit from caput to cauda. The data are con-sistent with the view that FMP activates sperm forward motility by enhancing the intrasperm cyclic AMP level and that extracellular bicarbonate and pH play a vital role in the initiation of sperm FM during the epi-didymal transit.

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