The corpora allata-corpora cardiaca (CA-CC) is an endocrine gland complex that regulates mosquito development and reproduction through the synthesis of juvenile hormone (JH). Epoxidase (Epox) is a key enzyme in the production of JH. We recently utilized CRISPR/Cas9 to establish an epoxidase-deficient (epox-/-) Aedes aegypti line. The CA from epox-/- mutants do not synthesize epoxidated JH III but methyl farneosate (MF), a weak agonist of the JH receptor, and therefore have reduced JH signalling. Illumina sequencing was used to examine the differences in gene expression between the CA-CC from wild type (WT) and epox-/- adult female mosquitoes. From 18,034 identified genes, 317 were significantly differentially expressed. These genes are involved in many biological processes, including the regulation of cell proliferation and apoptosis, energy metabolism, and nutritional uptake. In addition, the same CA-CC samples were also used to examine the microRNA (miRNA) profiles of epox-/- and WT mosquitoes. A total of 197 miRNAs were detected, 24 of which were differentially regulated in epox-/- mutants. miRNA binding sites for these particular miRNAs were identified using an in silico approach; they target a total of 101 differentially expressed genes. Our results suggest that a lack of epoxidase, besides affecting JH synthesis, results in the diminishing of JH signalling that have significant effects on Ae. aegypti CA-CC transcriptome profiles, as well as its miRNA repertoire.
- MeSH
- Aedes * genetika metabolismus MeSH
- corpora allata metabolismus MeSH
- exprese genu MeSH
- juvenilní hormony metabolismus MeSH
- mikro RNA * genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Juvenile hormones (JHs) are sesquiterpenoids synthesized by the corpora allata (CA). They play critical roles during insect development and reproduction. The first JH was described in 1934 as a "metamorphosis inhibitory hormone" in Rhodnius prolixus by Sir Vincent B. Wigglesworth. Remarkably, in spite of the importance of R. prolixus as vectors of Chagas disease and model organisms in insect physiology, the original JH that Wigglesworth described for the kissing-bug R. prolixus remained unidentified. We employed liquid chromatography mass spectrometry to search for the JH homologs present in the hemolymph of fourth instar nymphs of R. prolixus. Wigglesworth's original JH is the JH III skipped bisepoxide (JHSB3), a homolog identified in other heteropteran species. Changes in the titer of JHSB3 were studied during the 10-day long molting cycle of 4th instar nymph, between a blood meal and the ecdysis to 5th instar. In addition we measured the changes of mRNA levels in the CA for the 13 enzymes of the JH biosynthetic pathway during the molting cycle of 4th instar. Almost 90 years after the first descriptions of the role of JH in insects, this study finally reveals that the specific JH homolog responsible for Wigglesworth's original observations is JHSB3.
- MeSH
- biologická proměna * MeSH
- corpora allata chemie MeSH
- epoxidové sloučeniny chemie MeSH
- hemolymfa chemie MeSH
- kukla chemie fyziologie MeSH
- nymfa chemie fyziologie MeSH
- Rhodnius chemie fyziologie MeSH
- seskviterpeny chemie MeSH
- shazování tělního pokryvu fyziologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Seventeen species of the coleopteran series Cucujiformia are investigated for the presence and sequence of putative adipokinetic hormones (AKHs). Cucujiformia includes species from the major superfamilies, that is, Chrysomeloidea, Curculionoidea, Cucujoidea, and Tenebrionoidea. The clade Phytophaga in which the Chrysomeloidea and Curculionoidea reside, harbor very detrimental species for agriculture and forestry. Thus, this study aims not only to demonstrate the structural biodiversity of AKHs in these beetle species and possible evolutionary trends but also to determine whether the AKHs from harmful pest species can be used as lead substances for a future putative insecticide that is harmless to beneficial insects. Sequence analysis of AKHs is achieved by liquid chromatography coupled to mass spectrometry. Most of the investigated species contain AKH octapeptides in their corpora cardiaca, although previously published work also found a few decapeptides, which we comment on. The signature and sole AKH in cerambycidae Chrysomeloidea and Curculionoidea is Peram-CAH-I (pEVNFSPNW amide), which is also found in the majority of chrysomelidae Chrysomeloidea and in the one investigated species of Cucujoidea albeit in a few cases associated with a second AKH which can be either Peram-CAH-II (pELTFTPNW amide), Emppe-AKH (pEVNFTPNW amide), or Micvi-CC (pEINFTPNW amide). The most often encountered AKH in Tenebrionoidea, family Meloidae as well as family Tenebrionidae, is Tenmo-HrTH (pELNFSPNW amide) followed by Pyrap-AKH (pELNFTPNW amide) and a Tenmo-HrTH extended decapeptide (in Meloidae). Finally, we examine AKH sequences from 43 species of cucujiform beetles, including the superfamily Coccinelloidea for a possible lead compound for producing a cucujiform-specific pesticide.
- MeSH
- brouci chemie MeSH
- chromatografie kapalinová MeSH
- corpora allata chemie MeSH
- hmotnostní spektrometrie MeSH
- hmyzí hormony analýza chemie MeSH
- kyselina pyrrolidonkarboxylová analogy a deriváty analýza chemie MeSH
- oligopeptidy analýza chemie MeSH
- peptidy analýza chemie MeSH
- sekvence aminokyselin MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Anophelinae mosquitoes are vectors of human malaria, a disease that infects hundreds of millions of people and causes almost 600,000 fatalities annually. Despite their medical importance, laboratory studies on key aspects of Anophelinae reproductive biology have been limited, and in particular, relatively little is known about the role of juvenile hormone (JH) in the control of female reproduction. The study presented here attempts to fill a gap of knowledge in our understanding of the JH control of ovarian development in female Anophelinae mosquitoes, using Anopheles albimanus as a model. Our studies revealed that JH controls the tempo of maturation of primary follicles in An. albimanus in a similar manner to that previously described in Aedes aegypti. At adult eclosion JH hemolymph titer was low, increased in 1-day old sugar-fed insects, and decreased in blood fed individuals. JH titers decreased if An. albimanus females were starved, and were reduced if insects emerged with low teneral reserves, precluding previtellogenic ovarian development. However, absolute hemolymph titers were lower than Ae. aegypti. Decapitation experiments suggested that if teneral reserves are sufficient, factors from the head activate JH synthesis by the corpora allata (CA) during the first 9-12 h after adult emergence. In conclusion, our studies support the hypothesis that JH controls previtellogenic ovarian development in female An. albimanus mosquitoes, in a similar manner that have been described in Culicinae.
- MeSH
- Anopheles účinky léků růst a vývoj MeSH
- corpora allata cytologie účinky léků MeSH
- hemolymfa účinky léků MeSH
- juvenilní hormony farmakologie MeSH
- ovariální folikul cytologie účinky léků MeSH
- rozmnožování MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Three types of regulation of the corpus allatum (CA) activity were defined in females of the linden bug Pyrrhocoris apterus. First, short-term inhibition of the CA activity was found in starved or fed long-day females, or in short-day females. Inhibitory factor(s) are transmitted to the CA via nerves, but in vitro they might reach the CA via the incubation medium. Origin of the inhibition is the pars intercerebralis (PI). The inhibitory effect is reversible during short-term incubation in vitro. This short-term inhibition can be quickly restored by the presence of the brain-suboesophageal ganglion (BR-SG) with the PI or removed, by the presence of the BR-SG without the PI or by the absence of the BR-SG. Short-term inhibition is sufficient to inhibit the CA of starved long-day females, but it is not strong enough to inhibit the CA of diapausing bugs. Second, developmental stimulation of the CA activity by feeding in long-day females is associated with growth in size of the CA. Stimulation proceeds slowly (days) in vivo and reaches the CA from the PI via nerves. Activity of the CA is irreversible in vitro; it is maintained without any further stimulation by the PI, i.e. in the presence of the BR-SG without PI or in the absence of the BR-SG. In the intact BR-SG-CC-CA the developmental stimulation of the CA is compensated by short-term inhibition of similar strength. Therefore, the activity of large CA within the intact BR-SG-CC-CA (stimulated + inhibited) is similar to the activity of the small denervated CA (no stimulation + no inhibition). Third, long-term inhibition of the CA activity in short-day females, produced by the diapause inducing photoperiod in the PI, reaches the CA via nerves. However, in contrast to the short-term inhibition of the CA, it is irreversible during short-term incubation in vitro. The long-term inhibition can only be removed several days after disconnection of the CA from the brain in vivo.
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 24h (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 1.6times 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 (1.6times), AKH level in the corpora cardiaca (1.3times) and haemolymph (1.7times), 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.
- MeSH
- corpora allata metabolismus MeSH
- hemolymfa metabolismus MeSH
- Heteroptera metabolismus parazitologie MeSH
- hmyzí hormony metabolismus MeSH
- kyselina pyrrolidonkarboxylová analogy a deriváty metabolismus MeSH
- oligopeptidy metabolismus MeSH
- orgánová specificita MeSH
- Rhabditida fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Juvenile hormone (JH) produced by the corpus allatum (CA) stimulates vitellogenesis and reduces the synthesis of hexamerin proteins in adult females of Pyrrhocoris apterus. At present it is unknown whether the signaling pathway involving the JH receptor gene Methoprene tolerant (Met) and its binding partner Taiman (Tai), regulates the synthesis of accessory gland proteins (ACPs) and hexamerin proteins or effects male survival. Knockdown of genes by injecting Met dsRNA or Tai dsRNA, reduced the amount of ACPs whilst enhancing the amount of hexamerin mRNA in the fat body and the release of hexamerin proteins into haemolymph, as occurs after the ablation of CA. Lifespan was enhanced by injecting Met but not Tai dsRNA. Diapause associated with the natural absence of JH had a stronger effect on all these parameters than the ablation of CA or the knockdown of genes. This indicates there is an additional regulating agent. Both Met and Tai dsRNA induced a several fold increase in JH (JH III skiped bisepoxide) but a concurrent loss of Met or Tai disabled its function. This supports the view that the Met/Tai complex functions as a JH receptor in the regulation of ACPs and hexamerins.
- MeSH
- corpora allata fyziologie chirurgie MeSH
- genový knockdown MeSH
- hemolymfa chemie MeSH
- Heteroptera genetika fyziologie MeSH
- juvenilní hormony krev genetika metabolismus MeSH
- RNA interference MeSH
- rozmnožování MeSH
- signální transdukce * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články 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
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.
- MeSH
- cirkadiánní rytmus MeSH
- corpora allata fyziologie MeSH
- gastrointestinální trakt metabolismus MeSH
- Heteroptera metabolismus MeSH
- hmyzí geny MeSH
- hmyzí proteiny genetika metabolismus MeSH
- kryptochromy genetika metabolismus MeSH
- ovarium fyziologie MeSH
- regulace genové exprese * MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
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.
- MeSH
- corpora allata metabolismus MeSH
- Heteroptera fyziologie MeSH
- juvenilní hormony metabolismus MeSH
- rozmnožování MeSH
- sexuální chování zvířat MeSH
- Tilia parazitologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
