Ips typographus Dotaz Zobrazit nápovědu
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
The enzyme glucose-6-phosphate dehydrogenase (G6PD) of the bark beetle Ips typographus is derived from a gene that includes eight exons and spans over 7100 nucleotides (nt). By means of two transcription starts, the gene generates two mRNA isoforms that are present in similar amounts in the larvae, pupae and adults. The A isoform includes exon IA of 115 nt, which is followed by intron 1a extending to position 3457 of the gene. The B mRNA isoform begins with exon IB (100 nt) that occupies positions 3291-3390 within the 1a intron. Exons II to VII are included in both mRNA isoforms. The gene contains 31.6% (36.5% in the translated region) of the GC nucleotides. Two transcription starts and the exon/intron organization distinguish bark beetle G6PD from the homologous genes known in other insects. Two enzyme variants were detected in the protein extracts of individual bark beetles but their relationship to the A and B mRNA isoforms is uncertain.
- MeSH
- brouci enzymologie genetika MeSH
- financování organizované MeSH
- genom hmyzu MeSH
- glukosa-6-fosfátdehydrogenasa genetika MeSH
- hmyzí geny MeSH
- komplementární DNA MeSH
- konzervovaná sekvence MeSH
- messenger RNA MeSH
- molekulární evoluce MeSH
- molekulární sekvence - údaje MeSH
- počátek transkripce MeSH
- regulace genové exprese enzymů MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA MeSH
- Southernův blotting MeSH
- vývojová regulace genové exprese MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
Bark beetles vector symbiotic fungal species into their host trees during mass attacks. The symbiotic relationship with blue stain fungi of the Ascomycetes, including genera of Endoconidiophora (syn. = Ceratocystis), promotes successful establishment whereby the microbes help to overcome the host trees' defence and degrade toxic resins. This is the first study to evaluate both the volatile emissions from an insect-associated blue stain fungus over time and the insect response in a field trapping experiment. Volatile emissions from isolates of Endoconidiophora rufipennis (ER) were collected by solid-phase microextraction (SPME) and analysed by gas chromatography-mass spectroscopy (GC-MS) over a period of 30 days. This virulent North American fungus is closely related to E. polonica, a symbiotic fungus known from Eurasian spruce bark beetle Ips typographus.Nine volatiles were emitted by ER in substantial amounts: isoamyl acetate, sulcatone, 2-phenethyl acetate, geranyl acetone, geranyl acetate, citronellyl acetate, (R)- and (S)-sulcatol, and (R)-sulcatol acetate. A late peaking compound was geranyl acetone. In the field trapping experiment, three of the fungal volatiles (geranyl acetone, 2-phenethyl acetate and sulcatone) were tested in combination with a synthetic aggregation pheromone for I. typographus. Traps with geranyl acetone attracted lower numbers of I. typographus compared to traps with 2-phenethyl acetate, sulcatone or the pheromone alone as a control. The results showed that geranyl acetone acts as an anti-attractant and may act naturally on I. typographus as a cue from an associated fungus to signal an overexploited host.
- MeSH
- Ascomycota * fyziologie MeSH
- brouci * fyziologie MeSH
- feromony metabolismus MeSH
- kůra rostlin metabolismus MeSH
- nosatcovití * mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Overwintering success is one of the key aspects affecting the development and outbreaks of the spruce bark beetle, Ips typographus (L.) populations. This paper brings detailed analysis of cold tolerance, and its influence on overwintering success, in two Central European populations of I. typographus during two cold seasons. Evidence for a supercooling strategy in overwintering adults is provided. The lower lethal temperature corresponds well to the supercooling point that ranges between -20 and -22°C during winter months. The supercooled state is stabilized by the absence of internal ice nucleators and by seasonal accumulation of a mixture of sugars and polyols up to the sum concentration of 900 mM. The cryoprotective function of accumulated metabolites is probably based on increasing the osmolality and viscosity of supercooled body fluids and decreasing the relative proportion of water molecules available for lethal formation of ice nuclei. No activity of thermal hysteresis factors (stabilizers of supercooled state) was detected in hemolymph. Lethal times for 50% mortality (Lts50) in the supercooled state at -5, -10 or -15°C are weeks (autumn, spring) or even months (winter), suggesting relatively little mortality caused by chill injury. Lts50 at -15°C are significantly shorter in moist (6.9 days) than in dry (>42 days) microenvironment because there is higher probability of external ice nucleation and occurrence of lethal freezing in the moist situation.
- MeSH
- aklimatizace MeSH
- brouci fyziologie MeSH
- cukerné alkoholy metabolismus MeSH
- ekosystém MeSH
- hemolymfa metabolismus MeSH
- metabolismus sacharidů MeSH
- nízká teplota MeSH
- osmolární koncentrace MeSH
- voda fyziologie MeSH
- výběrové chování MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Geografické názvy
- Česká republika MeSH
- MeSH
- brouci mikrobiologie MeSH
- houby klasifikace MeSH
- Publikační typ
- přehledy MeSH
The spectrum of Mesostigmata mite species that are phoretic on the bark beetle Ips typographus has been well described. However, phoretic mite abundance has mostly been quantified by researchers who used only a single method for capturing bark beetles: pheromone traps. We therefore compared mite abundance using two beetle-capture methods. At a single location with high numbers of I. typographus in the eastern Czech Republic in 2013, beetles were collected with pheromone traps and from infested logs placed in emergence traps. In total 29,589 I. typographus beetles were captured using the two methods. Mite abundance was assessed on 2400 beetles from pheromone traps and on 955 beetles from emergence traps; in total 5805 phoretic mesostigmatid mites were detected. Six species of phoretic mites were captured using pheromone traps and four species using emergence traps. The number of phoretic mites per beetle was higher for beetles captured in emergence traps than for beetles captured in pheromone traps. The most abundant mite species overall were Dendrolaelaps quadrisetus, Uroobovella ipidis, and Trichouropoda polytricha. The seasonal dynamics of phoretic mites paralleled the seasonal dynamics of their hosts.
- MeSH
- feromony MeSH
- kůra rostlin MeSH
- nosatcovití * MeSH
- roční období * MeSH
- roztoči * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Bark beetles kill apparently vigorous conifers during epidemics by means of pheromone-mediated aggregation. During non-endemic conditions the beetles are limited to use trees with poor defense, like wind-thrown. To find olfactory cues that help beetles to distinguish between trees with strong or weak defense, we collected volatiles from the bark surface of healthy felled or standing Picea abies trees. Furthermore, living trees were treated with methyl jasmonate in order to induce defense responses. Volatiles were analyzed by combined gas chromatography and electroantennographic detection (GC-EAD) on Ips typographus antennae. Compounds eliciting antennal responses were characterized by single sensillum recording for identification of specific olfactory sensory neurons (OSN). Release of monoterpene hydrocarbons decreased, while oxygenated compounds increased, from spring to early summer in felled trees. In both beetle sexes particular strong EAD activity was elicited by trace amounts of terpene alcohols and ketones. 4-Thujanol gave a very strong response and the absolute configuration of the tested natural product was assigned to be (+)-trans-(1R,4S,5S)-thujanol by stereoselective synthesis and enantioselective gas chromatography. One type of OSN responded to all ketones and five other OSN were characterized by the type of compounds that elicited responses. Three new OSN classes were found. Of the eight EAD-active compounds found in methyl jasmonate-treated bark, the known anti-attractant 1,8-cineole was the one most strongly induced. Our data support the hypothesis that highly active oxygenated host volatiles could serve as positive or negative cues for host selection in I. typographus and in other bark beetles.
- MeSH
- acetáty farmakologie MeSH
- brouci fyziologie MeSH
- cyklopentany farmakologie MeSH
- elektrofyziologické jevy účinky léků MeSH
- kůra rostlin chemie účinky léků metabolismus MeSH
- monoterpeny chemická syntéza chemie farmakologie MeSH
- oxylipiny farmakologie MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
- smrk chemie metabolismus MeSH
- stereoizomerie MeSH
- styren chemie farmakologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Chytridiopsis typographi Weiser, 1954, the microsporidian pathogen of the spruce bark beetle, Ips typographus L. (Coleoptera: Scolytidae), has an early developmental period with plurinucleate mother cells, each of which produces a single bud. The globular bud is connected with the mother cell by a collar and the cellular constituents are pushed to the distant end of the bud. Both the mother cell and the bud continue to develop; the bud then separates from the mother cell and grows to produce a cell of the same type. Both cells then continue sporogonial development and produce sporophorous vesicles with 16-32 spores. The process of a single mother cell producing a single bud that grows to an identical stage is new in the development of C. typographi and has no analogy in other Microsporidia.
BACKGROUND: Bark beetles are major pests of conifer forests, and their behavior is primarily mediated via olfaction. Targeting the odorant receptors (ORs) may thus provide avenues towards improved pest control. Such an approach requires information on the function of ORs and their interactions with ligands, which is also essential for understanding the functional evolution of these receptors. Hence, we aimed to identify a high-quality complement of ORs from the destructive spruce bark beetle Ips typographus (Coleoptera, Curculionidae, Scolytinae) and analyze their antennal expression and phylogenetic relationships with ORs from other beetles. Using 68 biologically relevant test compounds, we next aimed to functionally characterize ecologically important ORs, using two systems for heterologous expression. Our final aim was to gain insight into the ligand-OR interaction of the functionally characterized ORs, using a combination of computational and experimental methods. RESULTS: We annotated 73 ORs from an antennal transcriptome of I. typographus and report the functional characterization of two ORs (ItypOR46 and ItypOR49), which are responsive to single enantiomers of the common bark beetle pheromone compounds ipsenol and ipsdienol, respectively. Their responses and antennal expression correlate with the specificities, localizations, and/or abundances of olfactory sensory neurons detecting these enantiomers. We use homology modeling and molecular docking to predict their binding sites. Our models reveal a likely binding cleft lined with residues that previously have been shown to affect the responses of insect ORs. Within this cleft, the active ligands are predicted to specifically interact with residues Tyr84 and Thr205 in ItypOR46. The suggested importance of these residues in the activation by ipsenol is experimentally supported through site-directed mutagenesis and functional testing, and hydrogen bonding appears key in pheromone binding. CONCLUSIONS: The emerging insight into ligand binding in the two characterized ItypORs has a general importance for our understanding of the molecular and functional evolution of the insect OR gene family. Due to the ecological importance of the characterized receptors and widespread use of ipsenol and ipsdienol in bark beetle chemical communication, these ORs should be evaluated for their potential use in pest control and biosensors to detect bark beetle infestations.
