Dopamine and octopamine in whole body extracts of the bulb mite

Summary Using high performance liquid chromatography with electrochemical detection, whole body extracts of the bulb mite,Rhizoglyphus echinopus (Fumouze and Robin), were found to contain the biogenic amines dopamine and octopamine at concentrations of 4.3±0.6 and 2.3±1.4 ng g^–1 wet weight, respectively. Adrenaline, noradrenaline, tyramine,N-methyldopamine,N-acetyldopamine, and 5-hydroxytryptamine, if present, were below the limits of detectability. This is the initial demonstration of the presence of octopamine in a mite species.     

Effects of serotonin and ketanserin on the functional morphology of chick down feather bulbi in vitro

Summary Chick feather bulbi cultured in vitro showed an increased DNA synthesis and a delayed keratinization after treatment with ketanserin, a serotonin₂ antagonist with wound-healing properties. In contrast, serotonin stimulates keratinization of the keratinocytes in the bulbus.     

A pivotal role for serotonin (5HT) in the regulation of beta adrenoceptors by antidepressants: reversibility of the action of parachlorophenylalanine by 5-hydroxytroptophan

Summary An acute reduction in the synaptic availability of serotonin (5HT) by p-chlorophenlalanine (PCPA) nullifies the decrease in the density of cortical beta adrenoceptors caused by desipramine (DMI) but does not appreciably alter the attenuation of the norepinephrine (NE) sensitive adenylate cyclase. The analysis of competition-binding curves of [³H]-dihydroalprenolol shows that the affinity of the agonist (–)-isoproterenol for cortical beta adrenoceptors is profoundly reduced following PCPA. This reduction in agonist affinity is enhanced by DMI. Resupplying 5HT by by-passing trptophan hydroxylase inhibition, by administering 5-hydroxytryptophan, converts a DMI non-responsive to a DMI responsive beta adrenoceptor population and shifts the markedly decreased agonist affinity towards the affinity values found in control preparations. The results demonstrate the pivotal role of 5HT in the regulation of the density and agonist affinity characteristics of cortical beta adrenoceptors and contribute to the scientific basis of the serotonin-norepinephrine link hypothesis of affective disorders.Acknowledgments. This work was supported by USPHS grant MH-29228 and the Tennessee Department of Mental Health and Mental Retardation. Present address of L. R. Sterank: NOVA Pharmaceutical Corporation, Baltimore (MD 21228, USA).     

A comparison of the activity of flight interneurones in locusts,crickets, dragonflies and mayflies

Summary The activity patterns of interneurones in the flight systems of dragonflies and mayflies were investigated using standard intracellular recording and staining techniques, and were compared with those of crickets and locusts. The results show several basic similarities in the operation of a central motor pattern generator for flight in all four groups of insects. These similarities can be explained as resulting from conservative evolution of flight pattern generating circuitry within the central nervous system.     

Photoperiodic regulation of mating behaviour in the linden bug,Pyrrhocoris apterus,is mediated by a brain inhibitory factor

Active inhibition of mating behaviour in a male insect is reported here for the first time. InPyrrhocoris apterus L. (Heteroptera), the most important inhibitory pathway runs from the pars intercerebralis (PI) of the brain and does not pass through the corpora allata. The inhibitory activity of the PI is promoted by short day conditions and suppressed by long days. As the effect of photoperiod is delayed, transfer procedures enabled us to record daily rhythms in mating behaviour during short days. While the extirpation of the PI results in a discrete phase shift of the long day rhythm, there is a much less significant phase shift after this operation during short days. Thus the PI has been shown to mediate the effect of photoperiod on both the inhibition and the rhythm of mating behaviour.     

Makisterone A and 24-methylenecholesterol from the ovaries of the honey bee,Apis mellifera L

Summary Makisterone A, a 28-carbon ecdysteroid (molting hormone) has been isolated from the ovaries of queen bees. Analysis by reversed-phase and silica high performance liquid chromatography (HPLC) in conjunction with a radioimmune assay (RIA) revealed about 11 ng of makisterone A present per gram of ovaries on a fresh weight basis. No C₂₇ ecdysteroids were detected. The predominant neutral sterol present was 24-methylenecholesterol.     

Increased vascular permeability induced in synovialis of the rat by histamine,serotonin and bradykinin

Résumé La perméabilité vasculaire de la membrane synoviale du rat est augmentée par l'histamine, la sérotonine et la bradykinine. Dans cette réaction la sérotonine est plus active que l'histamine et la bradykinine.

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L.P.B. is supported by a Medical Postgraduate Research Scholarship from the National Health and Medical Research Council of Australia.

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We are indebted to Associate ProfessorJ. Garcia-Lémé, University of São Paulo, Brazil, for advice.     

Heat production by balling in the Japanese honeybee,Apis cerana japonica as a defensive behavior against the hornet,Vespa simillima xanthoptera (Hymenoptera: Vespidae)

Summary As an effective counterattack strategy against predacious hornets, especiallyVespa simillima xanthoptera, workers ofApis cerana japonica showed a distinct balling reaction, usually involving 180–300 bees. This produced heat for as long as 20 min, giving rise to temperatures inside the ball higher than 46°C, which is lethal to the hornet but not to the bees.     

Time courses and refractoriness of enhanced vascular permeability induced by histamine,serotonin and bradykinin in synovialis of the rat

Summary Enhanced vascular permeability induced in synovialis of the rat by histamine and serotonin lasts 5–15 min and that induced by bradykinin less than 5 min. Synovialis of the rat becomes refractory to the permeability effects of repeated doses of each of these substances in the hour following initial application.This work was carried out while L.P.B. was supported by a Medical Postgraduate Scholarship from the National Health and Medical Research Council of Australia.     

Serotonin is localized in endothelial cells of coronary arteries and released during hypoxia: A possible new mechanism for hypoxia-induced vasodilatation of the rat heart

Summary In this report we demonstrate the immunocytochemical localization of serotonin in endothelial cells of rat coronary vessels and a significant increase in the release of serotonin into the perfusate of Langendorff rat heart preparations during hypoxia. It is suggested that serotonin, localized in endothelial cells, is released during hypoxia and could provide part of a pathophysiological mechanism for vasodilatation to protect the heart from damage due to hypoxia.This research was supported by the British Heart Foundation and the excellent technical assistance of Jon Bokor is gratefully acknowledged.     

Idealisation,genetic explanations and political behaviours: Notes on the anti-reductionist critique of genopolitics

The rapid development of genetic research, determined, among others, by the requirements of The Human Genome Project, and a gradual reorientation in the perception of the role of nature and culture in the process of shaping complex networks of human relations by some political scientists, result in the increasing application of genetic data and methods in research regarding political behaviours. One of the key philosophical objections against the studies of the genetic foundations of political behaviours is that of excessive reductionism. This is supposed to manifest itself in the inadequate selection of the level of analysis for the explained phenomenon, the incompleteness of explanations and their low utility. My findings show that this objection is not sufficiently supported by contemporary science. Both studies using classical behavioural genetic methodologies and studies using DNA-based methods show that genes most likely play a role in political behaviours. Emphasising the significance of genetic influences in the midst of multiple extra-genetic interactions generates highly idealised explanations. Using the conceptual apparatus of the deformational concept of culture, I have demonstrated that the omission of a number of important extra-genetic influences by researchers is a consequence of focusing on specific causal patterns. This omission, however, does not entail negating the influence of non-genetic factors and, importantly, it may not have to be permanent. Following this approach, if correct, the reductionism of research into the genetic foundations of political behaviours is a standard cognitive procedure applied in science.     

Increase in the total reducing substances in the hemolymph of the freshwater crab,Barytelphusa guerini,produced by a pesticide (DDT) and an indolealkylamine (serotonin)

Summary DDT and serotonin produced significant increases in the total reducing substances in the hemolymph of intact crabs,Barytelphusa guerini, apparently by triggering release of the hyperglycemic hormone.     

Inhibition and sex specific induction of spawning by serotonergic ligands in the zebra musselDreissena polymorpha (Pallas)

Serotonin (5-hydroxytryptamine, 5-HT) stimulates spawning in the zebra mussel (Dressena polymorpha), a macrofouling European bivalve that has recently invaded North America. To develop methods of controlling zebra mussel spawning, two vertebrate serotonin antagonists, methiothepin and metergoline, known to bind with high affinity to snail 5-HT receptors, were tested for their ability to block 5-HT-induced spawning in zebra mussels. Methiothepin inhibited 5-HT-induced spawning at concentrations as low as 10^–6 M. Metergoline (10^–4 M) inhibited 5-HT-induced spawning; however, at lower concentrations (10^–8 to 10^–5 M), metergoline by itself significantly induced spawning in male, but not female zebra mussels. Metergoline (10^–5 M)-induced male spawning was inhibited by 10^–5 M methiothepin. Thus, methiothepin is the most effective inhibitor and metergoline the most powerful inducer of spawning yet tested in zebra mussels.     

Bacterial serine proteases secreted by the autotransporter pathway: classification,specificity, and role in virulence

Serine proteases exist in eukaryotic and prokaryotic organisms and have emerged during evolution as the most abundant and functionally diverse group. In Gram-negative bacteria, there is a growing family of high molecular weight serine proteases secreted to the external milieu by a fascinating and widely employed bacterial secretion mechanism, known as the autotransporter pathway. They were initially found in Neisseria, Shigella, and pathogenic Escherichia coli, but have now also been identified in Citrobacter rodentium, Salmonella, and Edwardsiella species. Here, we focus on proteins belonging to the serine protease autotransporter of Enterobacteriaceae (SPATEs) family. Recent findings regarding the predilection of serine proteases to host intracellular or extracellular protein-substrates involved in numerous biological functions, such as those implicated in cytoskeleton stability, autophagy or innate and adaptive immunity, have helped provide a better understanding of SPATEs’ contributions in pathogenesis. Here, we discuss their classification, substrate specificity, and potential roles in pathogenesis.     

Y chromosome in the sibling speciesAnopheles atroparvus (van Thiel, 1927) andA. labranchiae (Falleroni, 1926) (Diptera: Culicidae): Differential behaviour of the short arm after acid-alkaline treatment and Coriphosphine-O staining

Summary An acid-alkaline treatment followed by Coriphosphine-O staining was used for detecting chromosomal differences between the 2 sibling speciesAnopheles atroparvus (van Thiel) andA. labranchiae (Falleroni) (Diptera: Culicidae). The short arm of the Y chromosome was found to stain differently in the 2 species.The authors wish to thank the entomologist C. Contini for collecting and classifyingA. labranchiae larvae and Prof. U. Bianchi and Prof. U. Laudani for helpful discussions and suggestions on the subject.     

Distribution of the blood flow supplied by the vertebral artery in rats: Anatomical,functional and pharmacological aspects

In rats, the vertebral artery makes only a minor contribution to the blood perfusion of the ponto-medullary area. This was measured with radioactive microspheres and was confirmed by methylmetacrylate casts and local injection of a centrally acting hypotensive drug.     

Inhibition of the reinitiation of meiosis in Xenopus laevis oocytes by three natural antiproteases: antipain, chymostatin, and leupeptin]

Oocytes incubated for 1 hr. in saline containing 1 mg/ml of antipain, leupeptin or chymostatin do not reinstate meiosis when progesterone or ionophore A 23187 are added. On the contrary such oocytes remain able to undergo meiosis when injected with cytoplasm of maturing oocytes (MPF), with Rabbit phosphorylase kinase or with Beef protein kinase. These results demonstrate that the loss of responsiveness to progesterone or ionophore is not due to toxic effects but rather to some interference with a key event which occurs prior to MPF action.     

Distribution of the blood flow supplied by the vertebral artery in rats: anatomical, functional and pharmacological aspects.

In rats, the vertebral artery make only a minor contribution to the blood perfusion of the ponto-medullary area. This was measured with radioactive microspheres and was confirmed by methylmetacrylate casts and local injection of a centrally acting hypotensive drug.