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  • 1. Albabtain, Reham
    et al.
    Azeem, Muhammad
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. Karolinska Institutet, Sweden.
    Wondimu, Zenebech
    Lindberg, Tulay
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Gustafsson, Anders
    Investigations of a Possible Chemical Effect of Salvadora persica Chewing Sticks2017In: Evidence-based Complementary and Alternative Medicine, ISSN 1741-427X, E-ISSN 1741-4288, article id 2576548Article in journal (Refereed)
    Abstract [en]

    Salvadora persica is commonly used chewing sticks in many parts of the world as an oral hygiene tool. This study measured the amount of benzyl isothiocyanate (BITC) released into the mouth and assessed its retention time in saliva. The study also tested if the released amount of BITC could potentially be antibacterial or cytotoxic. Twelve subjects brushed their teeth with fresh Miswak once, twice, and four times. The amount of BITC in the saliva and in the used brushes was quantified using gas chromatography-mass spectrometry. The antibacterial effect of BITC and Miswak essential oil (MEO) was tested against Haemophilus influenzae, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis. The cytotoxic effect on gingival fibroblasts and keratinocytes was tested using MTT. The highest amount of the active compounds was detected in saliva after using the Miswak tip for once and immediately. It significantly decreased when the Miswak tip was used more than once and thus after 10 min. The growth of the tested bacteria was inhibited by MEO and BITC in a dose dependent manner, P. gingivalis being the most sensitive. MTT assay showed that BITC and MEO were cytotoxic towards gingival fibroblasts while oral keratinocytes showed resistance. This study suggests that the Miswak tip should be cut before each use to ensure the maximum effect.

  • 2.
    Axelsson, Karolin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Biotechnology (BIO).
    Konstanzer, Vera
    KTH.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Terenius, Olle
    Seriot, Lisa
    KTH, School of Biotechnology (BIO).
    Nordenhem, Henrik
    Nordlander, Goran
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Tartu University, Estonia.
    Antifeedants Produced by Bacteria Associated with the Gut of the Pine Weevil Hylobius abietis2017In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 74, no 1, p. 177-184Article in journal (Refereed)
    Abstract [en]

    The pine weevil, Hylobius abietis, is a severe forest pest insect as it feeds on newly planted conifer seedlings. To identify and develop an antifeedant could be one step towards the protection of seedlings from feeding damage by the pine weevil. With the aim to trace the origin of the antifeedants previously found in feces of the pine weevil, we investigated the culturable bacteria associated with the gut and identified the volatiles they produced. Bacterial isolates were identified by 16S ribosomal RNA gene analysis. The volatile emissions of selected bacteria, cultivated on NB media or on the grated phloem of Scots pine twigs dispersed in water, were collected and analyzed by solid-phase microextraction gas chromatography-mass spectrometry. The bacterial isolates released a variety of compounds, among others 2-methoxyphenol, 2-phenylethanol, 3-methyl-1-butanol, 1-octen-3-ol, 3-octanone, dimethyl disulfide, and dimethyl trisulfide. A strong antifeedant effect was observed by 2-phenylethanol, which could thus be a good candidate for use to protect planted conifer seedlings against feeding damage caused by H. abietis.

  • 3.
    Azeem, Muhammad
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry. Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, Abbottabad 22060, Pakistan.
    Barba Aliaga, Marina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Borg-Karlson, Anna-Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. Division of Organic Chemistry, Institute of Technology, Tartu University, Tartu 50411, Estonia.
    Terenius, O.
    Broberg, A.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Heterobasidion-growth inhibiting Bacillus subtilis A18 exhibits medium- and age-dependent production of lipopeptides2019In: Microbiology Research, ISSN 0944-5013, E-ISSN 1618-0623, Vol. 223-225, p. 129-136Article in journal (Refereed)
    Abstract [en]

    Heterobasidion annosum s.s. and H. parviporum are severe pathogens of conifers causing butt rot and root rot thus reducing the economic value of timber. Here, the antifungal activity of Bacillus subtilis isolate A18 against these two Heterobasidion species was investigated. Five different culture media with different culture age were investigated to study the effect of substrate composition and culture age for metabolite production. Bacterial cultures and cell-free culture filtrates were tested for antifungal activity. Inhibition of fungal growth was analysed using the agar disc-diffusion method. MALDI-TOF and LC-HRMS analyses were used to identify the antifungal metabolites. Substrate composition and age of culture were found to be active variables with direct effect on the antifungal activity of bacterial culture extracts. High anti-fungal activity was observed when B. subtilis was cultured in PDB, SGB and LB media for four days. Mass-spectrometry analysis showed the presence of lipopeptides in culture filtrates identified as members of the surfactins, polymixins, kurstakins and fengycins. A culture filtrate containing fengycin-type lipopeptides showed the highest bioactivity against Heterobasidion species. Bacterial cultures had higher bioactivity compared to their respective cell free culture filtrates. The results of the present study suggest that B. subtilis A18 is a powerful biocontrol agent against Heterobasidion infections of tree wounds and stumps.

  • 4.
    Danielsson, Marie
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Zhao, Tao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. Department of Science and Technology, Örebro University, Örebro, Sweden.
    Borg-Karlson, Anna-Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Arthropod infestation sites and induced defence can be traced by emission from single spruce needles2019In: Arthropod-Plant Interactions, ISSN 1872-8855, E-ISSN 1872-8847, Vol. 13, no 2, p. 253-259Article in journal (Refereed)
    Abstract [en]

    Emissions of defence chemicals from Norway spruce seedlings can be induced by feeding arthropods or by exogenous hormonal application. Some defence chemicals may attract or repel associated arthropods. The aim of this study was to show that it is possible to detect and collect stress-induced volatiles from micro sites, such as at the scale of a single needle, in vivo by using SPME. Methyl jasmonate application on the stem of Norway spruce seedlings induced emission of (E)-beta-farnesene only from the needles closest to the application site. Emissions of (E)-beta-farnesene, (E,E)-alpha-farnesene and (E)-alpha-bisabolene were only detected from needles infested by the spider mite Oligonychus ununguis. The total volatile amount detected by SPME-GC-MS reached a considerable mass of 14 ng/needle/24 h, suggesting that emission from damaged and stressed conifers might have a larger impact on the macro climate than previously estimated.

  • 5. Elmhalli, Fawzeia
    et al.
    Garboui, Samira S.
    Borg-Karlson, Anna-Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Mozuraitis, Raimondas
    Baldauf, Sandra L.
    Grandi, Giulio
    The repellency and toxicity effects of essential oils from the Libyan plants Salvadora persica and Rosmarinus officinalis against nymphs of Ixodes ricinus2019In: Experimental & applied acarology, ISSN 0168-8162, E-ISSN 1572-9702, Vol. 77, no 4, p. 585-599Article in journal (Refereed)
    Abstract [en]

    Essential oils extracted from the leaves of Libyan Rosemary (Rosmarinus officinalis L.), and Miswak (Salvadora persica L.) were evaluated for their acaricidal and repellent effects on Ixodes ricinus L. nymphs (Acari: Ixodidae) using a bioassay based on an open filter paper method'. Rosmarinus officinalis leaf essential oil diluted to 0.5 and 1 mu l/cm(2) in acetone exhibited, respectively, 20 and 100% tick mortality after about 5h of exposure. A total of 50 and 95% of I. ricinus nymphs were killed by direct contact with the oil when exposed to lethal concentrations (LC)of 0.7 mu l/cm(2) (LC50) and 0.95 mu l/cm(2) (LC95), respectively. The LC50 (0.5 mu l/cm(2)) was reached before the end of the first 24h of exposure time (ET), as tick mortality at 24h was 60%. Salvadora persica leaf essential oil at 1 mu l/cm(2) showed a significant repellency effect against I. ricinus nymphs at 1.5h ET. A 95% repellency was observed at a repellent concentration (RC95) of 1 mu l/cm(2) of S. persica, but no significant mortality was recorded at this dose of S. persica oil. Gas chromatography-mass spectrometry analyses showed that the main monoterpenes in both oils were 1,8-cineol, -pinene, and -pinene, although in markedly different proportions. These results suggest that essential oils have substantial potential as alternative approaches for I. ricinus tick control.

  • 6.
    Eneh, Lynda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Fillinger, U.
    Human Hlth Theme, Int Ctr Insect Physiol & Ecol, Thomas Odhiambo Campus, Mbita, Kenya..
    Borg-Karlson, Anna-Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Rajarao, Gunaratna Kuttuva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Lindh, Jenny
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Anopheles arabiensis oviposition site selection in response to habitat persistence and associated physicochemical parameters, bacteria and volatile profiles2019In: Medical and Veterinary Entomology, ISSN 0269-283X, E-ISSN 1365-2915, Vol. 33, no 1, p. 56-67Article in journal (Refereed)
    Abstract [en]

    A better understanding of the oviposition behaviour of malaria vectors might facilitate the development of new vector control tools. However, the factors that guide the aquatic habitat selection of gravid females are poorly understood. The present study explored the relative attractiveness of similar artificial ponds (0.8 m(2)) aged at varying lengths prior to opening in such a way that wild Anopheles arabiensis could choose between ponds that were freshly set up, or were aged 4 or 17 days old, to lay eggs. Physicochemical parameters, bacterial profile and volatile organic compounds emitted from ponds were investigated over three experimental rounds. Fresh ponds contained on average twice as many An. arabiensis instar larvae (mean 50, 95% confidence interval (CI) = 29-85) as the ponds that had aged 4 days (mean = 24, 95% CI = 14-42) and 17 days (mean = 20, 95% CI: 12-34). Fresh ponds were associated with a significantly higher turbidity combined with higher water temperature, higher nitrite levels and a lower pH and chlorophyll level than the older ponds. Round by round analyses suggested that bacteria communities differed between age groups and also that 4-heptanone, 2-ethylhexanal and an isomer of octenal were exclusively detected from the fresh ponds. These characteristics may be useful with respect to developing attract and kill strategies for malaria vector control.

  • 7.
    Lopez-Goldar, Xose
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH). CSIC, Mision Biol Galicia, Pontevedra, Spain.;Ohio State Univ, Dept Plant Pathol, Columbus, OH 43210 USA.;INIA, Forest Res Ctr, Dept Forest Ecol & Genet, Madrid, Spain..
    Villari, Caterina
    Ohio State Univ, Dept Plant Pathol, Columbus, OH 43210 USA.;Univ Georgia, Daniel B Warnell Sch Forestry & Nat Resources, Athens, GA 30602 USA..
    Bonello, Pierluigi
    Ohio State Univ, Dept Plant Pathol, Columbus, OH 43210 USA..
    Borg-Karlson, Anna-Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Grivet, Delphine
    INIA, Forest Res Ctr, Dept Forest Ecol & Genet, Madrid, Spain.;Univ Valladolid, INIA, Sustainable Forest Management Res Inst, Palencia, Spain..
    Zas, Rafael
    CSIC, Mision Biol Galicia, Pontevedra, Spain..
    Sampedro, Luis
    CSIC, Mision Biol Galicia, Pontevedra, Spain..
    Inducibility of Plant Secondary Metabolites in the Stem Predicts Genetic Variation in Resistance Against a Key Insect Herbivore in Maritime Pine2018In: Frontiers in Plant Science, ISSN 1664-462X, E-ISSN 1664-462X, Vol. 9, article id 1651Article in journal (Refereed)
    Abstract [en]

    Resistance to herbivores and pathogens is considered a key plant trait with strong adaptive value in trees, usually involving high concentrations of a diverse array of plant secondary metabolites (PSM). Intraspecific genetic variation and plasticity of PSM are widely known. However, their ecology and evolution are unclear, and even the implication of PSM as traits that provide direct effective resistance against herbivores is currently questioned. We used control and methyl jasmonate (MJ) induced clonal copies of genotypes within families from ten populations of the main distribution range of maritime pine to exhaustively characterize the constitutive and induced profile and concentration of PSM in the stem phloem, and to measure insect herbivory damage as a proxy of resistance. Then, we explored whether genetic variation in resistance to herbivory may be predicted by the constitutive concentration of PSM, and the role of its inducibility to predict the increase in resistance once the plant is induced. We found large and structured genetic variation among populations but not between families within populations in resistance to herbivory. The MJ-induction treatment strongly increased resistance to the weevil in the species, and the genetic variation in the inducibility of resistance was significantly structured among populations, with greater inducibility in the Atlantic populations. Genetic variation in resistance was largely explained by the multivariate concentration and profile of PSM at the genotypic level, rather than by bivariate correlations with individual PSM, after accounting for genetic relatedness among genotypes. While the constitutive concentration of the PSM blend did not show a clear pattern of resistance to herbivory, specific changes in the chemical profile and the increase in concentration of the PSM blend after MJ induction were related to increased resistance. To date, this is the first example of a comprehensive and rigorous approach in which inducibility of PSM in trees and its implication in resistance was analyzed excluding spurious associations due to genetic relatedness, often overlooked in intraspecific studies. Here we provide evidences that multivariate analyses of PSM, rather than bivariate correlations, provide more realistic information about the potentially causal relationships between PSM and resistance to herbivory in pine trees.

  • 8.
    Lundborg, Lina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Nordlander, Goran
    Bjorklund, Niklas
    Nordenhem, Henrik
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Methyl Jasmonate-Induced Monoterpenes in Scots Pine and Norway Spruce Tissues Affect Pine Weevil Orientation2016In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 42, no 12, p. 1237-1246Article in journal (Refereed)
    Abstract [en]

    In large parts of Europe, insecticide-free measures for protecting conifer plants are desired to suppress damage by the pine weevil Hylobius abietis (L.). Treatment with methyl jasmonate (MeJA), a chemical elicitor already used in crop production, may enhance expression of chemical defenses in seedlings in conifer regenerations. However, in a previous experiment, MeJA treatment resulted in substantially better field protection for Scots pine (Pinus sylvestris L.) than for Norway spruce (Picea abies (L.) Karst.). Hypothesizing that the variations may be at least due partly to volatiles released by MeJA-treated seedlings and their effects on pine weevil orientation, we examined tissue extracts of seedlings (from the same batches as previously used) by two-dimensional GC-MS. We found that the MeJA treatment increased contents of the monoterpene (-)-beta-pinene in phloem (the weevil's main target tissue) of both tree species, however, the (-)-beta-pinene/(-)-alpha-pinene ratio increased more in the phloem of P. sylvestris. We also tested the attractiveness of individual monoterpenes found in conifer tissues (needles and phloem) for pine weevils using an arena with traps baited with single-substance dispensers and pine twigs. Trap catches were reduced when the pine material was combined with a dispenser releasing (-)-beta-pinene, (+)-3-carene, (-)-bornyl acetate or 1,8-cineole. However, (-)-alpha-pinene did not have this effect. Thus, the greater field protection of MeJA-treated P. sylvestris seedlings may be due to the selective induction of increases in contents of the deterrent (-)-beta-pinene, in contrast to strong increases in both non-deterrent (-)-alpha-pinene and the deterrent (-)-beta-pinene in P. abies seedlings.

  • 9.
    Lundborg, Lina
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH). CDEng Aquaculture.
    Sampedro, Luis
    Borg-Karlson, Anna-Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Zas, Rafael
    Effects of methyl jasmonate on the concentration of volatile terpenes in tissues of Maritime pine and Monterey pine and its relation to pine weevil feeding2018In: Trees, ISSN 0931-1890, E-ISSN 1432-2285Article in journal (Refereed)
  • 10. López-Goldar, X.
    et al.
    Villari, C.
    Bonello, P.
    Borg-Karlson, Anna-Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Grivet, D.
    Sampedro, L.
    Zas, R.
    Genetic variation in the constitutive defensive metabolome and its inducibility are geographically structured and largely determined by demographic processes in maritime pine2019In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745Article in journal (Refereed)
    Abstract [en]

    Interspecific phenotypic variation in plant secondary metabolites (PSM) is often explained by biotic and abiotic factors. However, patterns of variation within species do not clearly fit the theoretical predictions. Exploring how genetics, environment and demographic processes shape such variation among and within populations is crucial for understanding evolution of PSM, particularly in long-lived plants such as forest trees. Here, we quantified genetic variation in PSM among and within populations, and explored drivers of local adaptation by studying the role of climate as a source of population differentiation in PSM of maritime pine. Constitutive profile and concentrations of 63 PSM and their herbivory-associated inducibility were determined in the bark of 130 clonally replicated genotypes with known familial structure from 10 populations covering the distribution range of the species. We compared neutral and quantitative population genetic differentiation of PSM (F ST and Q ST ). Also, we accounted for population genetic structure and kinship among individuals when exploring climate–trait relationships. We found large population differentiation and additive genetic variation in constitutive PSM. Many PSM were inducible, although very low genetic variation was observed with respect to their inducibility. Q ST –F ST comparisons suggest that differentiation of most diterpenes, monoterpenes, and phenolics can be explained by neutral demographic processes. Spatially heterogeneous selection across populations leading to local adaptation was only found for total constitutive sesquiterpenes and a few individual PSM. After accounting for population genetic structure, only the constitutive concentration of two sesquiterpenes showing signs of diversifying selection was predicted by climate, with decreasing concentrations along a growth-prone climatic gradient. Synthesis. Evolutionary patterns of plant secondary metabolites depended on their chemical nature, with neutral differentiation governing most plant secondary metabolites. Evidence of local adaptation was only found for total constitutive sesquiterpenes and a few individual plant secondary metabolites. The low genetic variation in the inducibility of plant secondary metabolites suggests a conserved model of defensive induction in this species. Since population differentiation linked to past demographic history could lead to false positives of adaptive differentiation signals, accounting for the genetic relatedness among populations is required to infer the environmental determinants of intraspecific genetic variation in putatively adaptive traits such as plant defences.

  • 11. Mozuraitis, R.
    et al.
    Kutra, J.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Buda, V.
    Dynamics of putative sex pheromone components during heat periods in estrus-induced cows2017In: Journal of Dairy Science, ISSN 0022-0302, E-ISSN 1525-3198, Vol. 100, no 9, p. 7686-7695Article in journal (Refereed)
    Abstract [en]

    Determination of the optimal insemination time in dairy cows is vital for fertilization success and is a challenging task due to silent or weak signs of estrus shown by some cows. This can be overcome by combining several estrus detection methods, leading to higher detection rates. However, an efficient, noninvasive method for detecting estrus in cows is still needed. Chemical cues released by the cow during estrus have been proposed to have pheromonal properties and signal readiness to mate to the bull. Such cues could be used in an industrial setting to detect cows in estrus. However, no conclusive published data show temporal changes in putative sex pheromone levels during estrus. The goal of this study was to determine the temporal pattern of putative sex pheromone components during estrus and to assess the reproducibility of changes in pheromone concentration with respect to ovulation time. Two injections of the hormone PGF(2 alpha) were administered over a 2-wk interval to induce and synchronize the estrous cycles of 6 Holstein cows. The precise time of ovulation was determined by means of an ultrasound technique, and estrus was determined by visual observation. Using solid-phase microextraction gas chromatography-mass spectrometry techniques, we showed that acetic and propionic acids, which have been proposed to be putative sex pheromone components in cows, were present in the headspaces of all estrous and diestrous fecal samples, whereas 1-iodoundecane was not detected by solid-phase microextraction or by solvent extraction with diethyl ether. Low levels of acids were observed until 1 d before ovulation, at which point their concentrations increased, peaking around 0.5 d before ovulation. The application of labeled synthetic standards revealed that during the peak of release, 36 +/- 8 ng (average +/- SD) of acetic acid and 10 +/- 3 ng of propionic acid were present in 0.5-g samples of estrous-phase fecal matter compared with 19 +/- 5 and 2.3 +/- 1 ng of acetic and propionic acids, respectively, in the control diestrous samples. After the peak, the amounts of the compounds decreased sharply to match those of the control samples and afterward returned to the baseline readings. This decrease in the amounts of putative pheromone components was registered about 12 h before ovulation, indicating that acetic and propionic acids could be used as biomarkers for the electronic detection of ovulation.

  • 12.
    Zhao, Tao
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Ganji, Suresh
    Schiebe, Christian
    Bohman, Bjorn
    Weinstein, Philip
    Krokene, Paal
    Borg-Karlson, Anna-Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Unelius, C. Rikard
    Convergent evolution of semiochemicals across Kingdoms: bark beetles and their fungal symbionts2019In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 13, no 6, p. 1535-1545Article in journal (Refereed)
    Abstract [en]

    Convergent evolution of semiochemical use in organisms from different Kingdoms is a rarely described phenomenon. Tree-killing bark beetles vector numerous symbiotic blue-stain fungi that help the beetles colonize healthy trees. Here we show for the first time that some of these fungi are able to biosynthesize bicyclic ketals that are pheromones and other semiochemicals of bark beetles. Volatile emissions of five common bark beetle symbionts were investigated by gas chromatography-mass spectrometry. When grown on fresh Norway spruce bark the fungi emitted three well-known bark beetle aggregation pheromones and semiochemicals (exo-brevicomin, endo-brevicomin and trans-conophthorin) and two structurally related semiochemical candidates (exo-1,3-dimethyl-2,9-dioxabicyclo[3.3.1]nonane and endo-1,3-dimethyl-2,9-dioxabicyclo[3.3.1]nonane) that elicited electroantennogram responses in the spruce bark beetle Ips typographus. When grown on malt agar with C-13 D-Glucose, the fungus Grosmannia europhioides incorporated C-13 into exo-brevicomin and trans-conophthorin. The enantiomeric compositions of the fungus-produced ketals closely matched those previously reported from bark beetles. The production of structurally complex bark beetle pheromones by symbiotic fungi indicates cross-kingdom convergent evolution of signal use in this system. This signaling is susceptible to disruption, providing potential new targets for pest control in conifer forests and plantations.

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