Cold exposure depolarizes cells in insects due to a reduced electrogenic ion transport and a gradual increase in extracellular K+ concentration ([K+]). Cold-induced depolarization is linked to cold injury in chill-susceptible insects, and the locust, Locusta migratoria, has been shown to improve cold tolerance following cold acclimation through depolarization resistance. Here we investigate how cold acclimation influences depolarization resistance and how this resistance relates to improved cold tolerance. To address this question, we investigated if cold acclimation affects the electrogenic transport capacity and/or the relative K+ permeability during cold exposure by measuring membrane potentials of warm- and cold-acclimated locusts in the presence and absence of ouabain (Na+-K+ pump blocker) or 4-aminopyridine (4-AP; voltage-gated K+ channel blocker). In addition, we compared the membrane lipid composition of muscle tissue from warm- and cold-acclimated locust and the abundance of a range transcripts related to ion transport and cell injury accumulation. We found that cold-acclimated locusts are depolarization resistant due to an elevated K+ permeability, facilitated by opening of 4-AP-sensitive K+ channels. In accordance, cold acclimation was associated with an increased abundance of Shaker transcripts (gene encoding 4-AP-sensitive voltage-gated K+ channels). Furthermore, we found that cold acclimation improved muscle cell viability following exposure to cold and hyperkalemia even when muscles were depolarized substantially. Thus cold acclimation confers resistance to depolarization by altering the relative ion permeability, but cold-acclimated locusts are also more tolerant to depolarization.
- MeSH
- 4-aminopyridin farmakologie MeSH
- aklimatizace účinky léků fyziologie MeSH
- kosterní svalová vlákna účinky léků fyziologie MeSH
- Locusta migratoria fyziologie MeSH
- membránové potenciály účinky léků fyziologie MeSH
- nízká teplota * MeSH
- ouabain farmakologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Climate warming is expected to significantly affect plant-herbivore interactions. Even though direct effects of temperature on herbivores were extensively studied, indirect effects of temperature (acting via changes in host plant quality) on herbivore performance have rarely been addressed. We conducted multiple-choice feeding experiments with generalist herbivore Schistocerca gregaria feeding on six species of genus Impatiens cultivated at three different temperatures in growth chambers and a common garden. We also studied changes in leaf morphology and chemistry. We tested effects of temperature on plant palatability and assessed whether the effects could be explained by changes in the leaf traits. The leaves of most Impatiens species experienced the highest herbivory when cultivated at the warmest temperature. Traits related to leaf morphology (specific leaf area, leaf dry matter content and leaf area), but not to leaf chemistry, partly mediated the effects of temperature on plant palatability. Herbivores preferred smaller leaves with lower specific leaf area and higher leaf dry matter content. Our study suggests that elevated temperature will lead to changes in leaf traits and increase their palatability. This might further enhance the levels of herbivory under the increased herbivore pressure, which is forecasted as a consequence of climate warming.
- MeSH
- býložravci fyziologie MeSH
- fenotyp * MeSH
- Impatiens fyziologie MeSH
- klimatické změny * MeSH
- kobylky fyziologie MeSH
- listy rostlin fyziologie MeSH
- teplota MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In this paper, we propose an integrated biologically inspired visual collision avoidance approach that is deployed on a real hexapod walking robot. The proposed approach is based on the Lobula giant movement detector (LGMD), a neural network for looming stimuli detection that can be found in visual pathways of insects, such as locusts. Although a superior performance of the LGMD in the detection of intercepting objects has been shown in many collision avoiding scenarios, its direct integration with motion control is an unexplored topic. In our work, we propose to utilize the LGMD neural network for visual interception detection with a central pattern generator (CPG) for locomotion control of a hexapod walking robot that are combined in the controller based on the long short-term memory (LSTM) recurrent neural network. Moreover, we propose self-supervised learning of the integrated controller to autonomously find a suitable setting of the system using a realistic robotic simulator. Thus, individual neural networks are trained in a simulation to enhance the performance of the controller that is then experimentally verified with a real hexapod walking robot in both collision and interception avoidance scenario and navigation in a cluttered environment.
- MeSH
- chování zvířat fyziologie MeSH
- chůze fyziologie MeSH
- kobylky fyziologie MeSH
- neuronové sítě MeSH
- řízené strojové učení MeSH
- robotika přístrojové vybavení MeSH
- učení vyhýbat se fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The historic genus Pleistophora (Plistophora) is a highly polyphyletic clade with invertebrate Microsporidia reassigned to several new genera since the 1980s. Two genera, Endoreticulatus and Cystosporogenes, clearly separate into distinct but closely related clades based on small subunit ribosomal RNA analysis but are included in different families that are each polyphyletic. A microsporidium with morphology resembling the Endoreticulatus/Cystosporogenes clade was isolated from the grasshopper Poecilimon thoracicus from a site in Northwest Bulgaria. It produced intense infections in the digestive tract of the host but no behavioral changes were noted in infected individuals. Prevalence of the microsporidium increased over the active feeding season yearly. Mature spores were oval and measured 2.58±0.21 μm×1.34±0.24 μm, with 16 to approximately 32 spores in a parasitophorous vacuole. The spores were uninucleate and polar filament coils numbered 8-9 situated in a single row. The spore polaroplast consisted of an anterior lamellar section and a posterior vesicular section, and the posterior vacuole was reduced. Analyses of a 1221 bp partial SSU-rRNA sequence indicated that the isolate is more closely related to the Endoreticulatus clade than to Cystosporogenes, but shows earlier phylogenetic separation from species infecting Lepidoptera and represents a new species, Endoreticulatus poecilimonae. To compare sequences of Endoreticulatus spp. from Lepidoptera to those infecting other insect orders, an isolate, Microsporidium itiitiMalone (1985), described from the Argentine stem weevil, Listronotus bonariensis, was sequenced. Like the grasshopper isolate, the weevil isolate is closely related but basal to the lepidopteran Endoreticulatus clade. The original description combined with the new sequence data confirms species status and permits transfer of the isolate from Microsporidium, a genus erected for microsporidian species of uncertain taxonomic status, to Endoreticulatus.
- MeSH
- druhová specificita MeSH
- fylogeneze * MeSH
- kobylky mikrobiologie MeSH
- mikrosporidia neklasifikovaná klasifikace cytologie genetika MeSH
- molekulární sekvence - údaje MeSH
- sekvence nukleotidů MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The basal caeliferan family Tetrigidae is investigated to identify neuropeptides belonging to the adipokinetic hormone (AKH) family. The pygmy grasshopper Tetrix subulata contains in its corpus cardiacum two octapeptides as revealed by liquid chromatography coupled to electrospray ionization mass spectrometry. The less abundant peptide is the well-known Schgr-AKH-II (pELNFSTGW amide) which is suggested to be the ancestral AKH of Caelifera and Ensifera. The second peptide, Tetsu-AKH (pEFNFTPGW amide), is novel and quite unusual with its third aromatic residue at position 2. It is thought to be autapomorphic for Caelifera. Tetsu-AKH has hyperlipemic activity in T. subulata and in Schistocerca gregaria.
- MeSH
- adipokiny chemie izolace a purifikace farmakologie MeSH
- corpora allata metabolismus MeSH
- hmyzí proteiny chemie izolace a purifikace farmakologie MeSH
- kobylky chemie MeSH
- metabolismus lipidů účinky léků MeSH
- molekulová hmotnost MeSH
- sekvence aminokyselin MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Peptides of the adipokinetic hormone (AKH)/red pigment-concentrating hormone (RPCH) family were isolated and sequenced from the retrocerebral corpora cardiaca of four kissing bugs which are all vectors of the protozoan Trypanosoma cruzi responsible for Chagas' disease. The sequence of three novel AKHs were deduced from the multiple MS(N) electrospray mass data: the octapeptide pGlu-Leu-Thr-Phe-Ser-Thr-Asp-Trp amide (denoted Rhopr-AKH) in Rhodnius prolixus and Panstrongylus megistus, the nonapeptide pGlu-Leu-Thr-Phe-Thr-Pro-Asn-Trp-Gly amide (denoted Triin-AKH) in Triatoma infestans and the decapeptide pGlu-Leu-Thr-Phe-Ser-Asp-Gly-Trp-Gly-Asn amide (denoted Dipma-AKH) in Dipetalogaster maxima. The sequences were confirmed by identical behavior of natural and synthetic forms in reversed-phase HPLC and by CID-MS mass spectra. Conspecific injections of a dose of 10 pmol of the respective synthetic peptides resulted in a small but significant increase of the lipid concentration in the hemolymph. These experiments suggest that AKHs in kissing bugs act to regulate lipid metabolism, possibly during dispersal flights which is one of the mechanisms whereby the insects reach new outbreak areas. Copyright © 2012 Elsevier Inc. All rights reserved.
- MeSH
- hemolymfa metabolismus MeSH
- hmyzí hormony MeSH
- kobylky metabolismus účinky léků MeSH
- kyselina pyrrolidonkarboxylová * MeSH
- metabolismus lipidů MeSH
- oligopeptidy MeSH
- Panstrongylus * metabolismus MeSH
- Rhodnius * metabolismus MeSH
- sekvence aminokyselin MeSH
- sekvenční analýza proteinů MeSH
- Triatoma * metabolismus MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
A checklist is presented of the Orthoptera of the Czech Republic. Based on the critical revision of published data and previous lists of species, which often contained only general or questionable data and which often inaccurately cited each other, we found 96 species of Orthoptera belonging to the fauna of the Czech Republic. We emphasize those changes that are based on comparison with previous checklists. We provide information on missing, unclear, and extinct species and on newly detected species, and we confirm the status of species that have been missing for a long time (Leptophyes boscii, Polysarcus denticauda, Ruspolia nitidula, Eumodicogryllus bordigalensis, Tetrix bolivari, Mecostethus parapleurus). We also note those species for which only several individuals have been detected (Pteronemobius heydenii) or those survived only at a single locality (Platycleis montana, Aiolopus thalassinus, Dociostaurus brevicollis, Omocestus petraeus) or at two localities (Poecilimon intermedius, Platycleis veyseli, Pseudopodisma nagyi). Phaneroptera nana is recorded as new for Bohemia.
- MeSH
- Gryllidae klasifikace MeSH
- kobylky klasifikace MeSH
- kontrolní seznam MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
The diacylglycerols (DG) molecular species and their fatty acid (FA) composition were investigated by electrospray mass spectrometry (ESI-MS) and by gas chromatography with flame ionisation detection (GC-FID) in haemolymph of Locusta migratoria after application of adipokinetic hormones Locmi-AKH-I, -II and -III. The analyses showed (1) a heterogeneous distribution of individual DGs in haemolymph after the hormone application. The results revealed that mobilization of the DGs is molecular species-specific with the highest proportion of 34:1 DG (16:0/18:1 - mw 594Da) for all Locmi-AKHs bearing palmitic acid (C16:0) and oleic acid (C18:1) residues, and forming about 20% of the total mobilized DG content. (2) Analysis of fat body triacylglycerols revealed that all Locmi-AKHs mobilize the DGs selectively with the preference of those possessing the C18 and C16 FAs. The fat body FAs with carbon chain longer than 18 did not participate in the mobilization. (3) A distribution of FAs in the DG structures obtained by LC/ESI-MS, and FA analysis by GC-FID after transmethylation indicated a certain degree of Locmi-AKH selectivity toward the mobilized DGs and hence the FAs. The Locmi-AKH-I significantly prefers mobilization of DGs containing unsaturated FAs, while Locmi-AKH-II and -III prefer mobilization of saturated FAs.
- MeSH
- diglyceridy metabolismus MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
- hmyzí hormony metabolismus MeSH
- hmyzí proteiny metabolismus MeSH
- kyselina pyrrolidonkarboxylová analogy a deriváty metabolismus MeSH
- Locusta migratoria metabolismus MeSH
- oligopeptidy metabolismus MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
