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Isolation and structure of a novel charged member of the red-pigment-concentrating hormone-adipokinetic hormone family of peptides isolated from the corpora cardiaca of the blowfly Phormia terraenovae (Diptera).
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A hypertrehalosaemic neuropeptide from the corpora cardiaca of the blowfly Phormia terraenovae has been isolated by reversed-phase h.p.l.c., and 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 octapeptide has the sequence pGlu-Leu-Thr-Phe-Ser-Pro-Asp-Trp-NH2 and is clearly defined as a novel member of the RPCH/AKH (red-pigment-concentrating hormone/adipokinetic hormone) family of peptides. It is the first charged member of this family to be found. The synthetic peptide causes an increase in the haemolymph carbohydrate concentration in a dose-dependent fashion in blowflies and therefore is named 'Phormia terraenovae hypertrehalosaemic hormone' (Pht-HrTH). In addition, receptors in the fat-body of the American cockroach (Periplaneta americana) recognize the peptide, resulting in carbohydrate elevation in the blood. However, fat-body receptors of the migratory locust (Locusta migratoria) do not recognize this charged molecule, and thus no lipid mobilization is observed in this species. 相似文献
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Wilps H. Zebe E. 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1976,107(3):263-274
1. | Auditory stimuli consisting of tape-recorded natural sounds were used in a study of 129 neurons in Field L of the caudal neostriatum in the forebrain of curarized starlings (Sturnus vulgaris). |
2. | An extensive program of stimuli comprising many different signals (109 sound elements) was devised in order to permit identification of even very highly specialized neurons. |
3. | As a rule, the time courses of the neuronal responses parallel those of certain parameters or parameter combinations of the sound stimuli. The responses of a few very specialized neurons, however, did not reflect any distinguishable temporal substructure within the effective sounds. |
4. | 64 neuons were examined with respect to the number of stimuli, out of a sample of 80 sound elements, eliciting a response. 24 of these neurons responded to less than 10 of the 80 natural sounds. These include neurons responding only to a single sound or to sounds of a single type. |
5. | 30 of the 64 neurons responded most strongly, or exclusively, to sounds of a single type. |
6. | The criterion determining whether a neuron responds to a given sound may be a single parameter, a combination of parameters, or the entire complex of parameters describing the sound. |
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Density-dependent aposematism in the desert locust 总被引:1,自引:0,他引:1
Sword GA Simpson SJ El Hadi OT Wilps H 《Proceedings. Biological sciences / The Royal Society》2000,267(1438):63-68
The ecological processes underlying locust swarm formation are poorly understood. Locust species exhibit phenotypic plasticity in numerous morphological, physiological and behavioural traits as their population density increases. These density-dependent changes are commonly assumed to be adaptations for migration under heterogeneous environmental conditions. Here we demonstrate that density-dependent nymphal colour change in the desert locust Schistocerca gregaria (Orthoptera: Acrididae) results in warning coloration (aposematism) when the population density increases and locusts consume native, toxic host plants. Fringe-toed lizards (Acanthodactylus dumerili (Lacertidae)) developed aversions to high-density-reared (gregarious-phase) locusts fed Hyoscyamus muticus (Solanaceae). Lizards associated both olfactory and visual cues with locust unpalatability, but only gregarious-phase coloration was an effective visual warning signal. The lizards did not associate low rearing density coloration (solitarious phase) with locust toxicity. Predator learning of density-dependent warning coloration results in a marked decrease in predation on locusts and may directly contribute to outbreaks of this notorious pest. 相似文献
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Abstract: The Italian locust Calliptamus italicus is the most common and dangerous pest species of nearly the whole of Kazakhstan and neighbouring countries. This univoltine locust can aggregate and its hopper bands and adult swarms invade agricultural areas regularly and frequently cause significant damage to wheat, sunflowers, beans, etc. In the trials presented, two different Confidor formulations, namely Confidor 200 SL and 010 UL were tested on C. italicus hopper bands in Kazakhstan. The former formulation was tested twice – the mortality rates reached nearly 90% at the remarkably low dosage of 7.5 g a.i./ha. The ULV formulation 010 UL sprayed with 10 g a.i./ha caused about 75% mortality in 2 to 3 days. Preliminary observations did not show any impact on the non‐target organisms but further ecotoxicological field data are required. 相似文献
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