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Dalibor Kodrik - One of the best experts on this subject based on the ideXlab platform.
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changes in vitellogenin expression caused by nematodal and fungal infections in insects
The Journal of Experimental Biology, 2019Co-Authors: Dalibor Kodrik, Emad Ibrahim, Umesh Kumar Gautam, Radmila Capkova Frydrychova, Andrea Bednařova, Vaclav Kristůfek, Pavel JedlickaAbstract:This study examined the expression and role of vitellogenin (Vg) in the body of the firebug Pyrrhocoris apterus (Heteroptera, Insecta) during infection elicited by two entomopathogenic organisms, the nematode Steinernema carpocapsae and the fungus Isaria fumosorosea Infection by S. carpocapsae significantly upregulated Vg mRNA expression in the male body. The corresponding increase in Vg protein expression was also confirmed by electrophoretic and immunoblotting analyses. Remarkably, in females, the opposite tendency was noted. Nematodal infection significantly reduced both Vg mRNA and Vg protein expression levels in fat body and hemolymph, respectively. We speculate that infection of reproductive females reduces Vg expression to a level that is still sufficient for defense, but is insufficient for reproduction. This circumstance reduces energy expenditure and helps the individual to cope with the infection. Importantly, purified Vg significantly inhibited growth of Xenorhabdus spp., an entomotoxic bacteria isolated from S. carpocapsae. However, the effect of Vg against I. fumosorosea was not so obvious. The fungus significantly stimulated Vg gene expression in males; however, a similar increase was not recapitulated at the protein level. Nevertheless, in females, both mRNA and protein Vg levels were significantly reduced after the fungal infection. The obtained data demonstrate that Vg is probably an important defense protein, possibly with a specific activity. This considerably expands the known spectrum of Vg functions, as its primary role was thought to be limited to regulating egg development in the female body.
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beneficial effect of adipokinetic hormone on neuromuscular paralysis in insect body elicited by braconid wasp venom
Comparative Biochemistry and Physiology C-toxicology & Pharmacology, 2017Co-Authors: Haq Abdul Shaik, Archana Mishra, Dalibor KodrikAbstract:Abstract The effect of Habrobracon hebetor venom and the role of the adipokinetic hormone (AKH) in poisoned adult females of the firebug Pyrrhocoris apterus were studied 24 and 48 h after treatments. Venom application elicited total neuromuscular paralysis in firebugs, but the co-application of venom and Pyrap-AKH significantly reduced paralysis (up to 3.2 times) compared to the application of venom only. Although the mechanisms of their action are unknown, both agents might affect neuromuscular junctions. Venom application significantly increased the expression of both P. apterus Akh genes (Pyrap-Akh 5.4 times and Peram-Cah-II 3.6 times), as well as the level of AKHs in the central nervous system (2.5 times) and haemolymph (3.0 times). In the haemolymph, increased AKH levels might have led to the mobilization of stored lipids, which increased 1.9 times, while the level of free carbohydrates remained unchanged. Total metabolism, monitored by carbon dioxide production, significantly declined in paralysed P. apterus individuals (1.4 times and 1.9 times, 24 and 48 h after the treatment, respectively), probably because of a malfunction of the muscular system. The results suggest an active role of AKH in the defence mechanism against the stress elicited by neuromuscular paralysis, and the possible involvement of this hormone in neuronal/neuromuscular signalling.
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adipokinetic hormone activities in insect body infected by entomopathogenic nematode
Journal of Insect Physiology, 2017Co-Authors: Emad Ibrahim, Marketa Hejnikova, Haq Abdul Shaik, David Doležel, Dalibor KodrikAbstract:Abstract The role of adipokinetic hormone (AKH) in the firebug Pyrrhocoris apterus adults infected by the entomopathogenic nematode (EPN) Steinernema carpocapsae was examined in this study. It was found that co-application of EPN and AKH enhanced firebug mortality about 2.5 times within 24 h (from 20 to 51% in EPN vs. EPN + AKH treatments), and resulted in metabolism intensification, as carbon dioxide production in firebugs increased about 2.1 and 1.6 times compared to control- and EPN-treated insects, respectively. Accordingly, firebugs with reduced expression of AKH receptors showed a significantly lower mortality (by 1.6 to 2.9-folds), and lower general metabolism after EPN + AKH treatments. In addition, EPN application increased Akh gene expression in the corpora cardiaca (1.6 times), AKH level in the corpora cardiaca (1.3 times) and haemolymph (1.7 times), and lipid and carbohydrate amounts in the haemolymph. Thus, the outcomes of the present study demonstrate involvement of AKH into the anti-stress reaction elicited by the nematobacterial infection. The exact mechanism by which AKH acts is unknown, but results suggested that the increase of metabolism and nutrient amounts in haemolymph might play a role.
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role of adipokinetic hormone in stimulation of salivary gland activities the fire bug Pyrrhocoris apterus l heteroptera as a model species
Journal of Insect Physiology, 2014Co-Authors: Konstantin Vinokurov, Ales Tomcala, Natraj Krishnan, Andrea Bednařova, Tereza Staskova, Dalibor KodrikAbstract:Abstract The effect of adipokinetic hormone (Pyrap-AKH) in stimulating the function of insect salivary glands (SGs) in extra-oral digestive processes was studied in the firebug, Pyrrhocoris apterus L. (Heteroptera). The analyses were performed on samples of SGs and extracts of linden seeds, a natural source of the bug’s food. The SGs from 3-day old P. apterus females (when the food ingestion culminates), primarily contained polygalacturonase (PG) enzyme activity, whereas the level of lipase, peptidase, amylase and α-glucosidase was negligible. The transcription of PG mRNA and enzymatic activity were significantly increased in SGs after Pyrap-AKH treatment. The piercing and sucking of linden seeds by the bugs stimulated the intrinsic enzymatic cocktail of seeds (lipase, peptidase, amylase, glucosidase), and moreover the activity of these enzymes was significantly enhanced when the seeds were fed on by the Pyrap-AKH treated bugs. Similarly, a significant increase in PG activity was recorded in linden seeds fed on by hormonally-treated bugs or when injected by SG extract from hormonally treated ones as compared to untreated controls. The mechanism of AKH action in SGs is unknown, but likely involves cAMP (and excludes cGMP) as a second messenger, since the content of this compound doubled in SGs after Pyrap-AKH treatment. This new and as yet undescribed function of AKH in SGs is compared with the effect of this hormone on digestive processes in the midgut elucidated earlier.
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adipokinetic hormone exerts its anti oxidative effects using a conserved signal transduction mechanism involving both pkc and camp by mobilizing extra and intracellular ca2 stores
Comparative Biochemistry and Physiology C-toxicology & Pharmacology, 2013Co-Authors: Andrea Bednařova, Dalibor Kodrik, Natraj KrishnanAbstract:Abstract The involvement of members of the adipokinetic hormone (AKH) family in regulation of response to oxidative stress (OS) has been reported recently. However, despite these neuropeptides being the best studied family of insect hormones, their precise signaling pathways in their OS responsive role remain to be elucidated. In this study, we have used an in vitro assay to determine the importance of extra and intra-cellular Ca2 + stores as well as the involvement of protein kinase C (PKC) and cyclic adenosine 3′,5′-monophosphate (cAMP) pathways by which AKH exerts its anti-oxidative effects. Lipid peroxidation product (4-HNE) was significantly enhanced and membrane fluidity reduced in microsomal fractions of isolated brains (CNS) of Pyrrhocoris apterus when treated with hydrogen peroxide (H2O2), whereas these biomarkers of OS were reduced to control levels when H2O2 was co-treated with Pyrap-AKH. The effects of mitigation of OS in isolated CNS by AKH were negated when these treatments were conducted in the presence of Ca2 + channel inhibitors (CdCl2 and thapsigargin). Presence of either bisindolylmaliemide or chelyrythrine chloride (inhibitors of PKC) in the incubating medium also compromised the anti-oxidative function of AKH. However, supplementing the medium with either phorbol myristate acetate (PMA, an activator of PKC) or forskolin (an activator of cAMP) restored the protective effects of exogenous AKH treatment by reducing 4-HNE levels and increasing membrane fluidity to control levels. Taken together, our results strongly implicate the importance of both PKC and cAMP pathways in AKHs' anti-oxidative action by mobilizing both extra and intra-cellular stores of Ca2 +.
Radomir Socha - One of the best experts on this subject based on the ideXlab platform.
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the effect of adipokinetic hormone on midgut characteristics in Pyrrhocoris apterus l heteroptera
Journal of Insect Physiology, 2012Co-Authors: Dalibor Kodrik, Ales Tomcala, Konstantin Vinokurov, Radomir SochaAbstract:Abstract Digestive processes and the effect of adipokinetic hormone (Pyrap-AKH) on the amount of nutrients (lipids, proteins, and carbohydrates), and on the activity of digestive enzymes (lipases, peptidases, and carbohydrases) were studied in the midgut of the firebug, Pyrrhocoris apterus. The analyses were performed on samples of anterior (AM), middle (MM) and posterior (PM) midgut parts. The results revealed that the digestion of lipids, carbohydrates and proteins take place in the acidic milieu. The Pyrap-AKH treatment increased significantly the level of lipids and proteins in the midgut, and also the level of triacylglycerols (TGs) predominantly in the AM, and the level of diacylglycerols (DGs) in the MM. The increase was not uniform for all present TG and DG species – those containing the linoleic fatty acid were predominant. No hormonal effect on lipase activity was recorded, while peptidase and glucosidase activity was increased in the MM and PM. All these facts indicate that the Pyrap-AKH probably stimulates digestion by more intensive food ingestion or turnover, and perhaps by the stimulation of metabolite absorption; the activation of digestive enzymes seems to be secondary or controlled by other mechanisms.
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oxidative stress elicited by insecticides a role for the adipokinetic hormone
General and Comparative Endocrinology, 2011Co-Authors: Mirna Velki, Josef Veceřa, Dalibor Kodrik, Branimir K Hackenberger, Radomir SochaAbstract:Abstract Adipokinetic hormones (AKHs) are insect neuropetides responding to stress situations including oxidative stress. Two insecticides – endosulfan and malathion – were used to elicit oxidative stress conditions in the firebug Pyrrhocoris apterus , and the physiological functions of AKHs and their ability to activate protective antioxidative reactions were studied . The insecticide treatments elicited only a slight increase of the AKH level in CNS, but more intensive increase in haemolymph, which indicates an immediate involvement of AKH in the stress response. The treatment also resulted in a significant increase of catalase activity in the bug’s body and depletion of the reduced glutathione pool in the haemolymph, however, co-application of the insecticides with the AKH (80 pmol) reduced the effect. It has also been found that co-application of the insecticides with AKH increased significantly the bug mortality compared to that induced by the insecticides alone. This enhanced effect of the insecticides probably resulted from the stimulatory role of AKH on bug metabolism: the carbon dioxide production was increased significantly after the co-treatment by AKH with insecticides compared to insecticide treatment alone. It was hypothesized that the increased metabolic rate could intensify the insecticide action by an accelerated rate of exchange of metabolites accompanied by faster penetration of insecticides into tissues.
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Methoprene modifies adipokinetic hormone characteristics in the firebug Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae)
European Journal of Entomology, 2010Co-Authors: Dalibor Kodrik, Glenda Alquicer, Radomir SochaAbstract:In the present study the hypothesis that there is a feedback between juvenile hormone and adipokinetic hormones (AKHs) was investigated by topical application of the juvenoid methoprene on 9-day-old adult males of the firebug Pyrrhocoris apterus. This juvenoid (2 µg) induced a significant reduction of haemolymph lipids 24 h after treatment; however, it did not significantly reduce the ability of Pyrap-AKH (10 pmol/bug) to mobilize fat body lipids 6-72 h after the methoprene application. The same methoprene treatment elicited a significant increase of AKH content in the CNS (central nervous system: brain + corpora cardiaca + corpora allata) of experimental males 24 and 48 h after the juvenoid application. A significant decrease in the AKH level in the haemolymph was recorded at the same times and under the same experimental conditions. Similar results were observed when production of the AKHs from the CNS of topically treated males was measured under in vitro conditions. It is suggested that methoprene may reduce AKH release from the CNS resulting in an increase in the AKH content of the CNS due to accumulation rather than stimulation of AKH synthesis. Possible consequences of this phenomenon on the physiology of P. apterus are discussed.
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adipokinetic hormone pyrap akh enhances the effect of a pyrethroid insecticide against the firebug Pyrrhocoris apterus
Pest Management Science, 2009Co-Authors: Dalibor Kodrik, Iva Bartů, Radomir SochaAbstract:BACKGROUND: Adipokinetic hormones (AKHs) are insect neuropetides controlling stress situations including those elicited by insecticide treatment. The effect of Pyrap-AKH on the mortality of the firebug Pyrrhocoris apterus (L.) treated with the insecticide permethrin (Ambush 25 EC) was studied. RESULTS: Coinjection of 50 ng permethrin with 80 pmol Pyrap-AKH induced a significant 2.3-fold increase in bug mortality compared with the insecticide alone. The results were confirmed by topical coapplication of both agents (400 ng and 80 pmol respectively). Injections of 50 and 100 ng permethrin elicited a significant increase in the AKH level in CNS and the haemolymph. The results indicate an involvement of AKH in stress response to permethrin. The enhanced effect of insecticide by AKH treatments probably results from the stimulatory role in bug metabolism: carbon dioxide production was increased 3.5- and 2.5-fold respectively 1 and 3 h after permethrin treatment, and 4.3- and 3.4-fold after the permethrin plus AKH cotreatment, compared with the control. CONCLUSION: The elevation of metabolism could intensify the permethrin action by its faster penetration into tissues and by stimulation of biochemically active cells, and could be a reason for enhanced action of permethrin after its cotreatment with Pyrap-AKH.
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stimulatory effects of bioamines norepinephrine and dopamine on locomotion of Pyrrhocoris apterus l is the adipokinetic hormone involved
Comparative Biochemistry and Physiology B, 2008Co-Authors: Radomir Socha, Dalibor Kodrik, Rostislav ZemekAbstract:Abstract In the present paper we studied the effects of five biogenic amines – norepinephrine, dopamine, octopamine, serotonin and histamine – on the locomotory activity and mobilization of lipids in the adult females of the firebug, Pyrrhocoris apterus (L.). We tested the hypothesis (1) whether the stimulation of walking activity in the bugs injected with the bioamines is associated also with their hyperlipaemic effects, like in the case of adipokinetic hormones (AKHs), and (2) whether these effects are direct or mediated through a release of the AKHs into the hemolymph. The results demonstrated that all five tested biogenic amines mobilized the fat body lipids, but only norepinephrine and dopamine were capable to enhance the walking activity simultaneously with an elevation of the lipid level in the hemolymph. Those two amines had no effect on the level of AKHs in CNS, but modulated the AKHs level in hemolymph: norepinephrine increased it, while dopamine decreased it. The results indicate an apparent feedback between AKH characteristics and dopamine and norepinephrine actions occurring in this insect species. While the stimulatory effects of norepinephrine on lipid mobilization and walking activity could involve the release of bug’s own AKHs, dopamine probably employs an independent stimulatory pathway.
Martin Kaltenpoth - One of the best experts on this subject based on the ideXlab platform.
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actinobacteria as essential symbionts in firebugs and cotton stainers hemiptera pyrrhocoridae
Environmental Microbiology, 2013Co-Authors: Hassan Salem, Elisabeth Kreutzer, Sailendharan Sudakaran, Martin KaltenpothAbstract:Summary Actinobacteria engage in defensive symbioses with several insect taxa, but reports of nutritional contributions to their hosts have been exceptionally rare. Cotton stainers (Dysdercus fasciatus) and red firebugs (Pyrrhocoris apterus) (both Hemiptera, Pyrrhocoridae) harbour the actinobacterial symbionts Coriobacterium glomerans and Gordonibacter sp. as well as Firmicutes (Clostridium sp. and Lactococ- cus sp.) and Proteobacteria (Klebsiella sp. and a Rickettsiales bacterium) in the M3 region of their mid- gut. We combined experimental manipulation with community-level analyses to elucidate the function of the gut symbionts in both pyrrhocorid species. Elimination of symbionts by egg-surface sterilization resulted in significantly higher mortality and reduced growth rates, indicating that the microbial community plays an important role for host nutrition. Fitness of symbiont-deprived bugs could be completely restored by re-infection with the original microbiota, while reciprocal cross-infections of microbial com- munities across both pyrrhocorid species only par- tially rescued fitness, demonstrating a high degree of host-symbiont specificity. Community-level analyses by quantitative PCRs targeting the dominant bacterial strains allowed us to link the observed fitness effects to the abundance of the two actinobacterial symbi- onts. The nutritional mutualism with Actinobacteria may have enabled pyrrhocorid bugs to exploit Malva- les seeds as a food source and thereby possibly allowed them to occupy and diversify in this ecologi- cal niche.
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actinobacteria as essential symbionts in firebugs and cotton stainers hemiptera pyrrhocoridae
Environmental Microbiology, 2013Co-Authors: Hassan Salem, Elisabeth Kreutzer, Sailendharan Sudakaran, Martin KaltenpothAbstract:Summary Actinobacteria engage in defensive symbioses with several insect taxa, but reports of nutritional contributions to their hosts have been exceptionally rare. Cotton stainers (Dysdercus fasciatus) and red firebugs (Pyrrhocoris apterus) (both Hemiptera, Pyrrhocoridae) harbour the actinobacterial symbionts Coriobacterium glomerans and Gordonibacter sp. as well as Firmicutes (Clostridium sp. and Lactococ- cus sp.) and Proteobacteria (Klebsiella sp. and a Rickettsiales bacterium) in the M3 region of their mid- gut. We combined experimental manipulation with community-level analyses to elucidate the function of the gut symbionts in both pyrrhocorid species. Elimination of symbionts by egg-surface sterilization resulted in significantly higher mortality and reduced growth rates, indicating that the microbial community plays an important role for host nutrition. Fitness of symbiont-deprived bugs could be completely restored by re-infection with the original microbiota, while reciprocal cross-infections of microbial com- munities across both pyrrhocorid species only par- tially rescued fitness, demonstrating a high degree of host-symbiont specificity. Community-level analyses by quantitative PCRs targeting the dominant bacterial strains allowed us to link the observed fitness effects to the abundance of the two actinobacterial symbi- onts. The nutritional mutualism with Actinobacteria may have enabled pyrrhocorid bugs to exploit Malva- les seeds as a food source and thereby possibly allowed them to occupy and diversify in this ecologi- cal niche.
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geographical and ecological stability of the symbiotic mid gut microbiota in european firebugs Pyrrhocoris apterus hemiptera pyrrhocoridae
Molecular Ecology, 2012Co-Authors: Sailendharan Sudakaran, Hassan Salem, Christian Kost, Martin KaltenpothAbstract:Symbiotic bacteria often play an essential nutritional role for insects, thereby allowing them to exploit novel food sources and expand into otherwise inaccessible ecological niches. Although many insects are inhabited by complex microbial communities, most studies on insect mutualists so far have focused on single endosymbionts and their interactions with the host. Here, we provide a comprehensive characterization of the gut microbiota of the red firebug (Pyrrhocoris apterus, Hemiptera, Pyrrhocoridae), a model organism for physiological and endocrinological research. A combination of several culture-independent techniques (454 pyrosequencing, quantitative PCR and cloning/sequencing) revealed a diverse community of likely transient bacterial taxa in the mid-gut regions M1, M2 and M4. However, the completely anoxic M3 region harboured a distinct microbiota consisting of facultative and obligate anaerobes including Actinobacteria (Coriobacterium glomerans and Gordonibacter sp.), Firmicutes (Clostri-dium sp. and Lactococcus lactis) and Proteobacteria (Klebsiella sp. and a previously undescribed Rickettsiales bacterium). Characterization of the M3 microbiota in different life stages of P. apterus indicated that the symbiotic bacterial community is vertically transmitted and becomes well defined between the second and third nymphal instar, which coincides with the initiation of feeding. Comparing the mid-gut M3 microbial communities of P. apterus individuals from five different populations and after feeding on three different diets revealed that the community composition is qualitatively and quantitatively very stable, with the six predominant taxa being consistently abundant. Our findings suggest that the firebug mid-gut microbiota constitutes a functionally important and possibly coevolved symbiotic community.
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localization and transmission route of coriobacterium glomerans the endosymbiont of pyrrhocorid bugs
FEMS Microbiology Ecology, 2009Co-Authors: Martin Kaltenpoth, Sigrid A Winter, Aljoscha KleinhammerAbstract:Endosymbiotic gut bacteria play an essential role in the nutrition of many insects. Most of the nutritional interactions investigated so far involve gammaproteobacterial symbionts, whereas other groups have received comparatively little attention. Here, we report on the localization and the transmission route of the specific actinobacterial symbiont Coriobacterium glomerans from the gut of the red firebug, Pyrrhocoris apterus (Hemiptera: Pyrrhocoridae). The symbionts were detected by diagnostic PCRs and FISH in the midgut section M3, in the rectum and in feces of the bugs as well as in the hemolymph of some females. Furthermore, adult female bugs apply the symbionts to the surface of the eggs during oviposition, from where they are later taken up by the hatchlings. Surface sterilization of egg clutches generated aposymbiotic insects and thereby confirmed the vertical transmission route via the egg surface. However, symbionts were readily acquired horizontally when the nymphs were reared in the presence of symbiont-containing eggshells, feces, or adult bugs. Using diagnostic PCRs and partial sequencing of the 16S rRNA gene, closely related bacterial symbionts were detected in the cotton stainer bug Dysdercus fasciatus (Hemiptera: Pyrrhocoridae), suggesting that the symbiosis with Actinobacteria may be widespread among pyrrhocorid bugs.
Magdalena Hodkova - One of the best experts on this subject based on the ideXlab platform.
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endocrine regulation of non circadian behavior of circadian genes in insect gut
Journal of Insect Physiology, 2013Co-Authors: Adam Bajgar, David Doležel, Magdalena HodkovaAbstract:The linden bug Pyrrhocoris apterus exhibits a robust diapause response to photoperiod. Photoperiod strongly affected basal levels of circadian gene transcripts in the gut, via the neuroendocrine system. Cryptochrome 2 (cry2) mRNA level was much higher in diapause promoting short days (SD) than in reproduction promoting long days (LD), while Par Domain Protein 1 (Pdp1) mRNA level was higher in LD than in SD. The effect of photoperiod on gene expression was mediated by the neurosecretory cells of the pars intercerebralis (PI) and the juvenile hormone (JH) producing corpus allatum (CA). In LD-females, CA ablation resulted in SD-like levels of gene transcripts, while PI ablation had little effect. Conversely, in SD-females, CA ablation had only a little effect, while PI ablation resulted in LD-like levels of gene transcripts. Thus, the CA is responsible for LD-like characteristics of gene expression in reproducing females and the PI is responsible for SD-like characteristics of gene expression in diapausing females. A simultaneous ablation of both PI and CA revealed two roles of PI in SD-females: (1) inhibition of CA, and (2) weak CA-independent stimulation of cry2 mRNA. Overall, our results indicate that peripheral circadian gene expression in the gut reflects the physiological state of females (with respect to diapause or reproduction) rather than the external light-dark cycle.
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novel roles for the corpus allatum hormone in the cost of sexual interactions in the linden bug Pyrrhocoris apterus
Journal of Insect Physiology, 2011Co-Authors: Hana Blazkova, Jan Provaznik, Magdalena HodkovaAbstract:The cost of sexual interactions, usually expressed as a reduction of life-span, is a fundamental but poorly understood aspect of life. According to a widely accepted view, a rise in the "pro-aging" juvenile hormone (JH) might contribute to the decrease of life span caused by sexual interactions. We tested this hypothesis using the linden bug Pyrrhocoris apterus by removing the corpus allatum (CA), the source of JH. If JH is causally involved in the cost of sexual interactions, then the absence of CA (JH) should decrease the negative effect of sexual interactions on survival. As expected, ablating the CA significantly prolonged life-span of both virgin females and virgin males. Mated insects of both sexes lived significantly shorter than virgins. However, contrary to prediction, the decrease of life span by sexual interactions was similar in control and CA-ablated males, and was even enhanced in CA-ablated females. Another unexpected finding was that males paired with CA-ablated females lived almost as long as virgin males and significantly longer than did males paired with control females, although ablating the female CA did not cause any decrease in mating activity. On the other hand, females paired with CA-ablated males lived only slightly longer than did females paired with control males. These results highlight several important points. (1) In both genders, the negative effect of sexual interactions on insect's survival is not mediated by the insect's own CA. (2) The male CA has only minor effect on female survival, while (3) the female CA (JH) is principally responsible for the sex-induced reduction in the male survival.
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photoperiodic regulation of the phospholipid molecular species composition in thoracic muscles and fat body of Pyrrhocoris apterus heteroptera via an endocrine gland corpus allatum
Journal of Insect Physiology, 2002Co-Authors: Magdalena Hodkova, Petra Berkova, Helena ZahradnickovaAbstract:In the conventional view, the winter adaptation of membrane lipids is induced by temperature decrease. We propose that winter remodelling of membranes in Pyrrhocoris apterus is triggered by short-day photoperiod before the temperature decrease and changes caused by cold temperature represent the later phase of adaptation. The induction of diapause by short-day photoperiod results in an accumulation of phosphatidylethanolamine (PE) molecular species with C16:0/C18:2 acyl chains esterified to sn-1/sn-2 positions of glycerol at the expense of C18:0/C18:2. Proportions of C16:0/C18:2-PE are enhanced in short-day compared to long-day insects in both thoracic muscles (TM, 15.0 vs. 8.2%) and fat bodies (FB, 24.9 vs. 13.6 %). Proportions of C16:0/C18:2-PE are further enhanced during cold acclimation (to 26.5% in TM, 33.6 % in FB) at the expense of a more saturated species, C18:0/C18:1-PE. These changes are less prominent in phosphatidylcholines (PC). The effect of photoperiod seems to be mediated via the corpus allatum. Long-day non-diapause females deprived of their corpus allatum have the phospholipid molecular species profile similar to that found in short-day diapausing females. While the acyl chain remodelling is regulated by both photoperiod and temperature, the head group composition is regulated by temperature only. Similar to most other organisms, the level of PE is higher (50.3 vs. 43.5% in TM, 44.3 vs. 37.8% in FB) and that of PC is lower (35.9 vs. 40.2% in TM, 41.6 vs. 46.1 % in FB) at cold temperatures (≤1°C) compared to warm temperatures (≥16°C). In contrast to a general rule, the PE is less unsaturated than PC. In both TM and FB, proportions of unsaturated/unsaturated molecular species are consistently high in PC (56.3–67.5% in TM, 59.2–66.6% in FB), while they are consistently low in PE (19.1–26.7% in TM, 12.1–15.1% in FB). An adaptive significance of changes in the phospholipid composition for the low temperature and/or dehydration stress is discussed in relation to known physical properties of phospholipids.
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photoperiodic regulation of mating behaviour in the linden bug Pyrrhocoris apterus is mediated by a brain inhibitory factor
Cellular and Molecular Life Sciences, 1994Co-Authors: Magdalena HodkovaAbstract: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.
Alexei Yu Kostygov - One of the best experts on this subject based on the ideXlab platform.
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obligate development of blastocrithidia papi trypanosomatidae in the malpighian tubules of Pyrrhocoris apterus hemiptera and coordination of host parasite life cycles
PLOS ONE, 2018Co-Authors: Alexander O Frolov, Marina N Malysheva, Anna I Ganyukova, Vyacheslav Yurchenko, Alexei Yu KostygovAbstract:Blastocrithidia papi is a unique trypanosomatid in that its life cycle is synchronized with that of its host, and includes an obligate stage of development in Malpighian tubules (MTs). This occurs in firebugs, which exited the winter diapause. In the short period, preceding the mating of overwintered insects, the flagellates penetrate MTs of the host, multiply attached to the epithelial surface with their flagella, and start forming cyst-like amastigotes (CLAs) in large agglomerates. By the moment of oviposition, a large number of CLAs are already available in the rectum. They are discharged on the eggs' surface with feces, used for transmission of bugs' symbiotic bacteria, which are compulsorily engulfed by the newly hatched nymphs along with the CLAs. The obligate development of B. papi in MTs is definitely linked to the life cycle synchronization. The absence of peristalsis allow the trypanosomatids to accumulate and form dense CLA-forming subpopulations, whereas the lack of peritrophic structures facilitates the extensive discharge of CLAs directly into the hindgut lumen. The massive release of CLAs associated with oviposition is indispensable for maximization of the infection efficiency at the most favorable time point.
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life cycle of blastocrithidia papi sp n kinetoplastea trypanosomatidae in Pyrrhocoris apterus hemiptera pyrrhocoridae
European Journal of Protistology, 2017Co-Authors: Alexander O Frolov, Marina N Malysheva, Anna I Ganyukova, Vyacheslav Yurchenko, Alexei Yu KostygovAbstract:Blastocrithidia papi sp. n. is a cyst-forming trypanosomatid parasitizing firebugs (Pyrrhocoris apterus). It is a member of the Blastocrithidia clade and a very close relative of B. largi, to which it is almost identical through its SSU rRNA gene sequence. However, considering the SL RNA gene these two species represent quite distinct, not even related typing units. Morphological analysis of the new species revealed peculiar or even unique features, which may be useful for future taxonomic revision of the genus Blastocrithidia. These include a breach in the microtubular corset of rostrum at the site of contact with the flagellum, absence of desmosomes between flagellum and rostrum, large transparent vacuole near the flagellar pocket, and multiple vacuoles with fibrous content in the posterior portion of the cell. The study of the flagellates' behavior in the host intestine revealed that they may attach both to microvilli of enterocytes using swollen flagellar tip and to extracellular membranes layers using hemidesmosomes of flagellum. Laboratory experiments on B. papi transmission in P. apterus demonstrated that the parasite may be transmitted vertically (via contaminated surface of eggs) and horizontally (via contaminated substrate and/or necrophagy). We argue that the parasite exploits transmission mechanisms intended for obligate bacterial symbionts of P. apterus.
