Synthetic compounds that mimic the action of juvenile hormones (JHs) are founding members of a class of insecticides called insect growth regulators (IGRs). Like JHs, these juvenoids block metamorphosis of insect larvae to reproductive adults. Many biologically active juvenoids deviate in their chemical structure considerably from the sesquiterpenoid JHs, raising questions about the mode of action of such JH mimics. Despite the early deployment of juvenoid IGRs in the mid-1970s, their molecular effect could not be understood until recent discoveries of JH signaling through an intracellular JH receptor, namely the ligand-binding transcription factor Methoprene-tolerant (Met). Here, we briefly overview evidence defining three widely employed and chemically distinct juvenoid IGRs (methoprene, pyriproxyfen, and fenoxycarb), as agonist ligands of the JH receptor. We stress that knowledge of the target molecule is critical for using these compounds both as insecticides and as research tools.
- MeSH
- biologická proměna účinky léků MeSH
- fenylkarbamáty metabolismus farmakologie MeSH
- insekticidy chemie metabolismus farmakologie MeSH
- juvenilní hormony agonisté chemie farmakologie MeSH
- ligandy MeSH
- methopren metabolismus farmakologie MeSH
- pyridiny metabolismus farmakologie MeSH
- rezistence k insekticidům MeSH
- vývojová regulace genové exprese účinky léků MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy 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
This study examined the effect of two natural toxins (a venom from the parasitic wasp Habrobracon hebetor and destruxin A from the entomopathogenic fungus Metarhizium anisopliae), and one pathogen (the entomopathogenic fungus Isaria fumosorosea) on the activity of basic digestive enzymes in the midgut of the cockroach Periplaneta americana. Simultaneously, the role of adipokinetic hormones (AKH) in the digestive processes was evaluated. The results showed that all tested toxins/pathogens elicited stress responses when applied into the cockroach body, as documented by an increase of AKH level in the central nervous system. The venom from H. hebetor showed no effect on digestive enzyme activities in the ceca and midgut in vitro. In addition, infection by I. fumosorosea caused a decrease in activity of all enzymes in the midgut and a variable decrease in activity in the ceca; application of AKHs did not reverse the inhibition. Destruxin A inhibited the activity of all enzymes in the midgut but none in the ceca in vitro; application of AKHs did reverse this inhibition, and no differences between both cockroach AKHs were found. Overall, the results demonstrated the variable effect of the tested toxins/pathogens on the digestive processes of cockroaches as well as the variable ability of AKH to counteract these effects.
- MeSH
- aktivace enzymů MeSH
- depsipeptidy toxicita MeSH
- gastrointestinální trakt enzymologie MeSH
- hmyzí hormony farmakologie MeSH
- kyselina pyrrolidonkarboxylová analogy a deriváty farmakologie MeSH
- oligopeptidy farmakologie MeSH
- Periplaneta účinky léků enzymologie MeSH
- vosí jedy toxicita MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Despite a high toxicity, paraquat is one of the most widely used herbicides in the world. Our study evaluated the effect of paraquat exposure on antioxidant response and locomotion activity in Drosophila melanogaster. We examined the enzymatic activity of superoxide dismutase (SOD) and catalase, and the transcript levels of both enzymes. Flies were exposed to a wide range of paraquat concentrations (0.25 μM to 25 mM) for 12 h. SOD, at both transcript and enzymatic levels, revealed a biphasic dose-response curve with the peak at 2.5 μM paraquat. A similar dose-response curve was observed at transcript levels of catalase. Males revealed higher susceptibility to paraquat exposure, displaying higher lethality, increased levels of SOD activity, and increased peroxide levels than in females. We found that the exposure of females to 2.5 μM paraquat leads to an increase in locomotion activity. Because susceptibility to paraquat was enhanced by mating, the study supports the hypothesis of elevation of stress sensitivity as a physiological cost of reproduction.
- MeSH
- antioxidancia metabolismus MeSH
- chování zvířat účinky léků MeSH
- Drosophila melanogaster účinky léků metabolismus MeSH
- herbicidy toxicita MeSH
- katalasa metabolismus MeSH
- oxidace-redukce MeSH
- paraquat toxicita MeSH
- peroxidy metabolismus MeSH
- rozmnožování účinky léků MeSH
- sexuální faktory MeSH
- superoxiddismutasa metabolismus MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A serine protease was isolated from midguts of the bumblebee male Bombus terrestris by a combination of precipitation procedures with column chromatography. The purified enzyme exhibited two bands with molecular masses of 25 and 26 kDa as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. These bands showed a proteolytic activity in zymography assay. Midgut enzymes showed optimum proteolytic activity at pH 9 and 35°C using N-succinyl-L-alanyl-L-alanyl-L-prolyl-L-phenyl-alanine 4-nitroanilide as a substrate. The Michaelis constant (Km) and maximum reaction rate (Vmax) were 0.55±0.042 mM and 0.714±0.056 μmol p-nitroalanine produced min(-1) mg protein(-1) , respectively. Inhibition was affected by trypsin inhibitor, but not by phenylmethylsulfonyl fluoride and N-tosyl-L-phenylalanine chloromethyl ketone, which indicated the trypsin-like but not chymotrypsin-like specificity. The identity of the serine protease was confirmed by nanoliquid-tandem mass spectrometry. Eleven unique peptides of the B. terrestris serine protease were found. It shows high homology to a previously reported B. ignitus serine protease covering more than 65% of the protein amino acid sequence.
- MeSH
- gastrointestinální trakt enzymologie MeSH
- molekulární sekvence - údaje MeSH
- sekvence aminokyselin MeSH
- serinové proteasy izolace a purifikace metabolismus MeSH
- včely enzymologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The ingestion of chromogenic or fluorescent substrates for protease detection enables the visualization of digestive processes in mites in vivo due to their transparent bodies. The substrates for protease detection were offered to Lepidoglyphus destructor, and the resulting signals were observed in specimens under a compound microscope. The protease activity was successfully localized using chromogenic substrates (azoalbumin, AAPpNA, SAAPFpNA, elastin-orcein, SA(3) pNA, ZRRpNA, ArgpNA, and MAAPMpNA) and fluorescent substrates (casein-fluorescein, albumin-fluorescein, AAPAMC, BAAMC, ZRRAMC, ArgAMC, and AGPPPAMC). No activity was detected using the keratin azure and BApNA substrates. In the mesodeum, trypsin-like activity generated by hydrolysis of the BApNA substrate was not observed, but the BAAMC substrate allowed the visualization of trypsin-like activity in food boli in the posterior mesodeum. The results indicate that cathepsins B, D, and G and cathepsin H or aminopeptidase-like activities are present in the midgut of L. destructor. Among these activities, cathepsin D-like activity was identified for the first time in the gut of L. destructor. All proteases mentioned are produced in the mesodeal lumen and form the food bolus together with ingested food, afterward passing through the gut to be defecated. The method used enables the visualization of protease activities in the gut of transparent animals.
Ips typographus (L.), the eight-spined spruce bark beetle, causes severe damage throughout Eurasian spruce forests and suitable nuclear markers are needed in order to study its population structure on a genetic level. Two closely related genes encoding α-amylase in I. typographus were characterized and named AmyA and AmyB. Both α-amylase paralogs consisted of six exons and five introns. AmyA encodes a polypeptide of 483 amino acids, whereas AmyB has two alternative transcripts encoding polypeptides of 483 and 370 amino acids. The expression levels of both genes were high during larval stage and adulthood. The AmyB transcripts were absent in the pupal stage. A modification of the allozyme staining method allowed us to detect two clusters of bands on the electrophoretic gel that may correspond to the two α-amylase genes. There was a correlation between the lack of AmyB expression in pupa and the absence of the fast migrating isozyme cluster at this stage, suggesting that the faster migrating isoforms are products of the AmyB gene, whereas the slowly migrating bands are derived from the AmyA.
- MeSH
- alfa-amylasy genetika metabolismus MeSH
- brouci enzymologie genetika MeSH
- ektroforéza na škrobovém gelu MeSH
- elektroforéza v polyakrylamidovém gelu MeSH
- fylogeneze MeSH
- hmyzí proteiny genetika metabolismus MeSH
- izoenzymy genetika metabolismus MeSH
- klonování DNA MeSH
- messenger RNA metabolismus MeSH
- molekulární sekvence - údaje MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- sekvenční homologie aminokyselin MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Microplate assays with 96 wells were optimized to screen proteolytic activities in mite homogenates. Whole-mite extracts of Acarus siro, Aleuroglyphus ovatus, Tyrophagus putrescentiae, Tyroborus lini, Carpoglyphus lactis, Lepidoglyphus destructor, and Dermatophagoides farinae exhibited non-specific proteolytic activity in buffers from pH 2 to 12, and three peaks of highest activity at pH 3, 5-6, and 10 were distinguished. The reducing agent Tris(2-carboxyethyl)phosphine hydrochloride decreased general proteolytic activity on azocasein at pH 5 and 6. The results obtained on two non-specific substrates, azocasein and azoalbumin, showed highly different ranks of the species at pH 5 and 6. Proteolytic activities toward N(α)-Benzoyl-D,L-arginine 4-nitroanilide hydrochloride, N-Succinyl-L-alanyl-L-alanyl-L-prolyl-L-phenylalanine 4-nitroanilide, N-Succinyl-L-alanyl-L-alanyl-L-alanine 4-nitroanilide, Benzyloxycarbonyl-L-arginine-L-arginyl 4-nitroanilide, and N-Methoxysuccinyl-L-alanyl-L-alanyl-L-prolyl-L-methionine 4-nitroanilide (MAAPMpNA) were highest at alkaline pH, but the activity toward MAAPMpNA was also high at pH 5 and 6. In contrast, N-Succinyl-L-alanyl-L-alanyl-L-phenylalanine 4-nitroanilide (AAPpNA) and L-arginyl 4-nitroanilide (ArgpNA) had the highest activity recorded at pH 6. The high activities observed on AAPpNA, ArgpNA, and MAAPMpNA at digestive pH suggest that enzymes present in these extracts could have the majority of proteolysis in the mite gut. Evidence of the presence of proteolytic activities on all tested substrates and in all the tested mite homogenates suggests that the proteolytic activities may contribute to allergenicity. Poor or undetected hydrolytic activities of mite extracts toward substrates for keratin and collagen at digestive pH underline the importance of ecological interactions between mites and microorganisms in the utilization of such substrates.
- MeSH
- Acaridae enzymologie MeSH
- albuminy metabolismus MeSH
- druhová specificita MeSH
- fosfiny MeSH
- kaseiny metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- oligopeptidy metabolismus MeSH
- proteasy metabolismus MeSH
- substrátová specifita MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- MeSH
- dopamin fyziologie MeSH
- Drosophilidae růst a vývoj MeSH
- serotonin fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
