lnu.sePublications
Change search
Link to record
Permanent link

Direct link
BETA
Bohman, Björn
Publications (10 of 13) Show all publications
Zhao, T., Ganji, S., Bohman, B., Weinstein, P., Krokene, P., Borg-Karlsson, A.-K. & Unelius, C. R. (2019). Convergent evolution of semiochemicals across Kingdoms: bark beetles and their fungal symbionts. The ISME Journal, 13(6), 5-1545
Open this publication in new window or tab >>Convergent evolution of semiochemicals across Kingdoms: bark beetles and their fungal symbionts
Show others...
2019 (English)In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 13, no 6, p. 5-1545Article in journal (Refereed) Published
Abstract [en]

Convergent evolution of semiochemical use in organisms from different Kingdoms is a rarely described phenomenon. Treekilling 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 13C D-Glucose, the fungus Grosmannia europhioides incorporated 13C 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.

Place, publisher, year, edition, pages
Nature Publishing Group, 2019
National Category
Chemical Sciences Ecology
Research subject
Natural Science, Ecological chemistry
Identifiers
urn:nbn:se:lnu:diva-71867 (URN)10.1038/s41396-019-0370-7 (DOI)000468529400012 ()30770902 (PubMedID)2-s2.0-85061750036 (Scopus ID)
Available from: 2018-03-27 Created: 2018-03-27 Last updated: 2019-08-29Bibliographically approved
Bohman, B., Weinstein, A. M., Unelius, C. R. & Lorenzo, M. G. (2018). Attraction of Rhodnius prolixus males to a synthetic female-pheromone blend. Parasites & Vectors, 11, Article ID 418.
Open this publication in new window or tab >>Attraction of Rhodnius prolixus males to a synthetic female-pheromone blend
2018 (English)In: Parasites & Vectors, ISSN 1756-3305, E-ISSN 1756-3305, Vol. 11, article id 418Article in journal (Refereed) Published
Abstract [en]

Background: The triatomine bug Rhodnius prolixus Stal, 1859 (Heteroptera: Reduviidae) is the primary vector of Chagas disease in Colombia and Venezuela. An important step in controlling Chagas disease is monitoring the growth and spread of bug populations to inform effective management. Such monitoring could be carried out using pheromone traps. To develop effective pheromone traps, it is vital to understand the pheromone chemistry of R. prolixus. Previous studies have found that female R. prolixus metasternal gland secretions induce males to: leave shelters, take off, orientate during walking, aggregate around mating pairs, and mate. This study aims to identify a synthetic blend of female metasternal gland compounds that could be used to attract R. prolixus. Results: We investigated the electrophysiological activity of the ten most abundant compounds in female R. prolixus metasternal glands using single sensillum recordings. In total we obtained 60 recordings from basiconic sensilla in male R. prolixus. In 31 of these recordings, responses to individual compounds were observed. Each of the ten tested compounds elicited neuron responses in a minimum of eight recordings. Having confirmed their electrophysiological activity, we tested these ten compounds by presenting them to male Rhodnius prolixus in a 7 olfactometer. Male bugs showed a significant preference for the blend of metasternal gland compounds compared to the clean air control. Conclusions: A simple blend of ten compounds found in female R. prolixus metasternal glands is attractive to conspecific males. All compounds in the blend are either commercially available at low cost, or easily synthetically prepared from simple precursors. We hope that this blend will be evaluated as a lure for pheromone traps in field bioassays.

Place, publisher, year, edition, pages
BioMed Central, 2018
Keywords
Rhodnius prolixus, Chagas disease, SSR, Olfactometer, Pheromone, Metasternal gland, Trap, Volatiles
National Category
Biological Sciences Chemical Sciences
Research subject
Natural Science, Ecological chemistry
Identifiers
urn:nbn:se:lnu:diva-77398 (URN)10.1186/s13071-018-2997-z (DOI)000438713100001 ()30012183 (PubMedID)2-s2.0-85050075082 (Scopus ID)
Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2019-08-29Bibliographically approved
Unelius, C. R., Bohman, B. & Nordlander, G. (2018). Comparison of Phenylacetates with Benzoates and Phenylpropanoates as Antifeedants for the Pine Weevil, Hylobius abietis. Journal of Agricultural and Food Chemistry, 66(44), 11797-11805
Open this publication in new window or tab >>Comparison of Phenylacetates with Benzoates and Phenylpropanoates as Antifeedants for the Pine Weevil, Hylobius abietis
2018 (English)In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 66, no 44, p. 11797-11805Article in journal (Refereed) Published
Abstract [en]

This study concludes an extensive investigation of antifeedants for the pine weevil, Hylobius abietis (Coleoptera: Curculionidae), an economically important pest of planted conifer seedlings. Building on the previously reported antifeedant effects of benzoates and phenylpropanoids (aromatic compounds with one- or three-carbon-atom substituents on the benzene ring), we here report the antifeedant effects of compounds with two-carbon-atom side chains (i.e., phenylacetates). We also present new results; the best antifeedants from the benzoate class were tested at 10-fold lower concentrations in order to find the optimal antifeedants. Generally, for all three compound classes, efficient antifeedants were found to have one or two methyl, chloro, or methoxy substituents on the aromatic ring. For monosubstituted phenylpropanoids, the substituent preferably should be in the para-position. In the search for synergistic antifeedant effects among the three compound classes, combinations of compounds from the three classes were tested in binary and ternary mixtures.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
pine weevil, Hylobius abietis, synergism, conifer-seedling protection, feeding deterrent, structure activity relationships
National Category
Ecology Chemical Sciences
Research subject
Natural Science, Ecological chemistry
Identifiers
urn:nbn:se:lnu:diva-79004 (URN)10.1021/acs.jafc.8b03830 (DOI)000449888000029 ()30350979 (PubMedID)2-s2.0-85056229450 (Scopus ID)
Available from: 2018-12-06 Created: 2018-12-06 Last updated: 2019-08-29Bibliographically approved
Bohman, B., Flematti, G. R. & Unelius, C. R. (2017). Practical one-pot stereospecific preparation of vicinal and 1,3-diols. Tetrahedron Letters, 58(1), 75-77
Open this publication in new window or tab >>Practical one-pot stereospecific preparation of vicinal and 1,3-diols
2017 (English)In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 58, no 1, p. 75-77Article in journal (Refereed) Published
Abstract [en]

A facile one-pot synthesis providing vicinal diols and 1,3-diols in >95% stereoisomeric purity from commercially available enantiopure hydroxy esters has been developed. The esters were reduced with DIBALH and alkylated in situ with 4-pentenylmagnesium bromide, which after workup generated the title diols as diastereomeric pairs. These pairs were easily separated by preparative chromatography, affording products with retained stereoisomeric purity from the starting materials. This method represents an expedient preparation of many common natural products, such as cerambycid beetle pheromones and intermediates towards bicyclic acetal bark beetle pheromones. (C) 2016 Elsevier Ltd. All rights reserved.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Diols, DIBALH, Grignard, Acetals, Pheromone
National Category
Biological Sciences
Research subject
Natural Science, Ecological chemistry
Identifiers
urn:nbn:se:lnu:diva-60803 (URN)10.1016/j.tetlet.2016.11.101 (DOI)000392038800018 ()2-s2.0-85006288720 (Scopus ID)
Available from: 2017-02-21 Created: 2017-02-21 Last updated: 2019-09-10Bibliographically approved
Unelius, C. R., Schiebe, C., Bohman, B., Andersson, M. N. & Schlyter, F. (2014). Non-Host Volatile Blend Optimization for Forest Protection against the European Spruce Bark Beetle, Ips typographus. PLoS ONE, 9(1), Article ID e85381.
Open this publication in new window or tab >>Non-Host Volatile Blend Optimization for Forest Protection against the European Spruce Bark Beetle, Ips typographus
Show others...
2014 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 1, article id e85381Article in journal (Refereed) Published
Abstract [en]

Conifer feeding bark beetles (Coleoptera, Curculionidae, Scolytinae) pose a serious economic threat to forest production. Volatiles released by non-host angiosperm plants (so called non-host volatiles, NHV) have been shown to reduce the risk of attack by many bark beetle species, including the European spruce bark beetle, Ips typographus. However, the most active blend for I. typographus, containing three green leaf volatiles (GLVs) in addition to the key compounds trans-conophthorin (tC) and verbenone, has been considered too expensive for use in large-scale management. To lower the cost and improve the applicability of NHV, we aim to simplify the blend without compromising its anti-attractant potency. Since the key compound tC is expensive in pure form, we also tested a crude version: technical grade trans-conophthorin (T-tC). In another attempt to find a more cost effective substitute for tC, we evaluated a more readily synthesized analog: dehydroconophthorin (DHC). Our results showed that 1-hexanol alone could replace the three-component GLV blend containing 1-hexanol, (3Z)-hexen-1-ol, and (2E)-hexen-1-ol. Furthermore, the release rate of tC could be reduced from 5 mg/day to 0.5 mg/day in a blend with 1-hexanol and (-)-verbenone without compromising the anti-attractant activity. We further show that T-tC was comparable with tC, whereas DHC was a less effective anti-attractant. DHC also elicited weaker physiological responses in the tC-responding olfactory receptor neuron class, providing a likely mechanistic explanation for its weaker anti-attractive effect. Our results suggest a blend consisting of (-)-verbenone, 1-hexanol and technical trans-conophthorin as a cost-efficient anti-attractant for forest protection against I. typographus.

National Category
Ecology
Research subject
Natural Science, Ecological chemistry
Identifiers
urn:nbn:se:lnu:diva-32448 (URN)10.1371/journal.pone.0085381 (DOI)000329925800043 ()2-s2.0-84897974655 (Scopus ID)
Available from: 2014-02-24 Created: 2014-02-24 Last updated: 2017-12-05Bibliographically approved
Unelius, C. R., Park, K.-C. -., McNeill, M., Wee, S. L., Bohman, B. & Suckling, D. M. (2013). Identification and electrophysiological studies of (4S,5S)-5-hydroxy-4-methyl-3-heptanone and 4-methyl-3,5-heptanedione in male lucerne weevils. Die Naturwissenschaften, 100(2), 135-143
Open this publication in new window or tab >>Identification and electrophysiological studies of (4S,5S)-5-hydroxy-4-methyl-3-heptanone and 4-methyl-3,5-heptanedione in male lucerne weevils
Show others...
2013 (English)In: Die Naturwissenschaften, ISSN 0028-1042, E-ISSN 1432-1904, Vol. 100, no 2, p. 135-143Article in journal (Refereed) Published
Abstract [en]

An investigation to identify a sex or aggregation pheromone of Sitona discoideus GyllenhAyenl (Coleoptera: Curculionidae) is presented. Antenna flicking and attraction behaviors evoked by conspecifics of both sexes were recorded in arena bioassays, where attraction of females to males was observed. Air entrainment of both males and females was conducted in separate chambers. Gas chromatographic-mass spectrometric analysis of headspace volatiles revealed that two male-specific compounds, 4-methyl-3,5-heptanedione (major) and (4S,5S)-5-hydroxy-4-methyl-3-heptanone (minor), were emitted during the autumnal post-aestivatory flight period. The stereoisomers of the minor component were separated by enantioselective gas chromatography and their absolute configurations assigned by NMR (diastereomers) and the known preference of enantioselective transesterification reactions catalyzed by Candida antarctica lipase B. Electroantennogram and single sensillum recording studies indicate that 4-methyl-3,5-heptanedione as well as all individual stereoisomers of 5-hydroxy-4-methyl-3-heptanone are detected by the antennae of male and female S. discoideus. Further, single sensillum recordings suggest that both sexes of S. discoideus have specialized olfactory receptor neurons (ORNs) for detecting 4-methyl-3,5-heptanedione and different populations of stereoselective ORNs for detecting the stereoisomers of 5-hydroxy-4-methyl-3-heptanone. Some of these stereoselective ORNs appear to be sex-specific in S. discoideus.

Keywords
Sitona discoideus, Lucerne weevil, Medicago, Pheromone, 4-Methyl-3, 5-heptanedione, (4S, 5S)-5hydroxy-4-methyl-3-heptanone
National Category
Biochemistry and Molecular Biology
Research subject
Natural Science, Ecological chemistry
Identifiers
urn:nbn:se:lnu:diva-24746 (URN)10.1007/s00114-012-1003-4 (DOI)000314275500003 ()2-s2.0-84875270516 (Scopus ID)
Available from: 2013-03-12 Created: 2013-03-12 Last updated: 2017-12-06Bibliographically approved
Bohman, B., Troger, A., Franke, S., Lorenzo, M. G., Francke, W. & Unelius, C. R. (2011). Structure Elucidation and Synthesis of Dioxolanes Emitted by Two Triatoma Species (Hemiptera Reduviidae). Journal of natural products (Print), 74(4), 690-694
Open this publication in new window or tab >>Structure Elucidation and Synthesis of Dioxolanes Emitted by Two Triatoma Species (Hemiptera Reduviidae)
Show others...
2011 (English)In: Journal of natural products (Print), ISSN 0163-3864, E-ISSN 1520-6025, Vol. 74, no 4, p. 690-694Article in journal (Refereed) Published
Abstract [en]

Volatiles from the metastemal glands of two species Of true bugs of the Triatominae subfamily, Triatoma brasiliensis and Triatoma infestans, Were analyzed by SPME-GC/MS. Two sets of new natural products were found: (4S,5S)- and (4R,SR)-2,2,4-triethyl-5-methyl-1,3-dioxolane (1) (major component) and (45*,5S*)-2,4-diethyl-2,S-dimethyl-1,3-dioxolane (2) (trace component),-,(2R/S,4S,SS)- as well as (2R/S,4R,5R)-4-ethyl-5-methyl-2-(1-methylethyl)-1,3-dioxolane (3) (minor component), (2R/S,4S*,5S*).-4-ethyl-5-methyl-2-(1-methylpropyl)-1,3-dioxolane (4), (trace component), and (2R/S,4S*,5S*)-4-ethyl-5-methyl-2-(2-methylpropyl)-1,3-dioxolane (5) (trace component). Syntheses of optically active 1 and 3 were carried out by reacting pure,enantiomers of 2,3-pentanediol with 3-pentanone or 2-methylpropanal. The preparation of, pure 1 stereoisomers of 2,3-pentanediol involved a novel key step for the synthesis of secondary alcohols: the reduction of a carboxylic ester by means of DIBAH and in situ alkylation of the intermediate by Grignard reaction at low temperature Starting from the pure enantiomers of methyl lactate; all four stereoisoniers of 2,3-pentanediol were synthesized. and transformed, to the corresponding isomers of 1 and 2. Relative configurations of the natural products and enantiomeric compositions of naturally occurring 1 and :2 were determined by comparison of their mass spectra and gas chromatographic retention times (co-injection) I with those of authentic reference samples.

Keywords
chagas-disease, chemical communication, rhodnius-prolixus, esters, rearrangements, derivatives, volatiles, aldehydes, acetals, ketones
National Category
Ecology Chemical Sciences
Research subject
Natural Science, Ecological chemistry
Identifiers
urn:nbn:se:lnu:diva-14872 (URN)10.1021/np100748r (DOI)000289742300023 ()2-s2.0-79955421763 (Scopus ID)
Note

753CL Times Cited:0 Cited References Count:23

Available from: 2011-10-10 Created: 2011-10-10 Last updated: 2017-12-08Bibliographically approved
Unelius, C. R., Bohman, B., Lorenzo, M., Tröger, A., Franke, S. & Francke, W. (2010). (4S,5S)-2,2,4-Triethyl-5-methyl-1,3-dioxolane: A New Volatile Released by a Triatomine Bug. Organic Letters, 12(24), 5601-5603
Open this publication in new window or tab >>(4S,5S)-2,2,4-Triethyl-5-methyl-1,3-dioxolane: A New Volatile Released by a Triatomine Bug
Show others...
2010 (English)In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 12, no 24, p. 5601-5603Article in journal (Refereed) Published
Abstract [en]

Adults of the triatomine bug, Triatoma brasiliensis release 2,2,4-triethyl-5-methyl-1,3-dioxolane (1) as a mixture of the (4S,5S)- and (4R,5R)-enantiomers in a ratio of 4:1. Among the volatile acetals identified from insects so far, this is the first example resulting from an intermolecular condensation of a carbonyl moiety and a diol substructure.

Keywords
chemical ecology, dioxolanes, semiochemicals, Triatomines
National Category
Ecology Organic Chemistry
Research subject
Natural Science, Ecological chemistry
Identifiers
urn:nbn:se:lnu:diva-10126 (URN)10.1021/ol102165q (DOI)000285081300001 ()2-s2.0-78650314356 (Scopus ID)
Available from: 2011-01-17 Created: 2011-01-17 Last updated: 2017-12-11Bibliographically approved
Vitta, A., Bohman, B., Unelius, C. R. & Lorenzo, M. (2009). Behavioral and Electrophysiological Responses of Triatoma brasiliensis Males to Volatiles Produced in the Metasternal Glands of Female. Journal of Chemical Ecology, 35(10), 1212-1221
Open this publication in new window or tab >>Behavioral and Electrophysiological Responses of Triatoma brasiliensis Males to Volatiles Produced in the Metasternal Glands of Female
2009 (English)In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 35, no 10, p. 1212-1221Article in journal (Refereed) Published
Abstract [en]

In many insects, mate finding is mediated by volatile sex pheromones, but evidence for this phenomenon in triatomines (Heteroptera: Reduviidae) is still fragmentary. Recently, it was shown that metasternal glands (MGs) are involved in producing signals related to the sexual communication of Triatoma infestans and Rhodnius prolixus. Based on this, we tested whether MG volatiles could be involved in the sexual communication of Triatoma brasiliensis. Odor-mediated orientation responses were studied by using a T-tube olfactometer. These tests showed that males exhibit positive anemotaxis when confronted with adult odor-laden air currents. Moreover, females that had their metasternal glands occluded did not elicit significant orientation by males. Compounds produced by the MGs of T. brasiliensis females were identified by means of SPME, GC-FID, and GC-MS, with achiral and chiral columns. All substances identified were ketones and alcohols, and similar compound profiles were found in the secretions produced by both sexes. The most abundant compounds identified were 3-pentanone, followed by (4R)-methyl-1-heptanol, 3-pentanol, and (2S)-methyl-1-butanol. In addition, GC-EAD recordings showed that the antennae of males responded to several of the main components of female MG secretions. Our results showed that compounds produced by the MGs of T. brasiliensis females are involved in the sexual communication of this species.

National Category
Organic Chemistry Ecology
Research subject
Natural Science, Ecological chemistry
Identifiers
urn:nbn:se:lnu:diva-2122 (URN)10.1007/s10886-009-9709-2 (DOI)
Available from: 2010-04-06 Created: 2010-04-06 Last updated: 2017-12-12Bibliographically approved
Bohman, B. & Unelius, C. R. (2009). Synthesis of all four stereoisomers of 5-hydroxy-4-methyl-3-heptanone using plants and oyster mushrooms. Tetrahedron, 65(42), 8697-8701
Open this publication in new window or tab >>Synthesis of all four stereoisomers of 5-hydroxy-4-methyl-3-heptanone using plants and oyster mushrooms
2009 (English)In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 65, no 42, p. 8697-8701Article in journal (Refereed) Published
Abstract [en]

All four possible stereoisomers of 5-hydroxy-4-methyl-3-heptanone were synthesized from common achiral reagents using fast, straightforward organic synthesis, including the use of whole tissue of Daucus carota, Solanum melongena, and Pleurotus ostreatus.

National Category
Organic Chemistry Ecology
Research subject
Natural Science, Ecological chemistry
Identifiers
urn:nbn:se:lnu:diva-2038 (URN)10.1016/j.tet.2009.08.049 (DOI)
Available from: 2010-04-06 Created: 2010-04-06 Last updated: 2017-12-12Bibliographically approved
Organisations

Search in DiVA

Show all publications