| 1. |
- Azeem, Muhammad
(författare)
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Microbes Associated with Hylobius abietis : A Chemical and Behavioral Study
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is based on three inter-related studies: the first part deals with the microbial consortium, the identification of microbes and their volatiles, the second part deals with the study of bio-chemical control methods of two conifer pests; the pine weevil Hylobius abietis (L.) and the root rot fungi Heterobasidion spp., and the third part describes the production of styrene by a fungus using forest waste.The large pine weevil (Hylobius abietis L.) is an economically important pest insect of conifers in reforestation areas of Europe and Asia. The female weevils protect their eggs from feeding conspecifics by adding frass (mixture of weevil feces and chewed bark) along with the eggs. In order to understand the mechanism behind frass deposition at the egg laying site and to find repellents/antifeedants for pine weevils, microbes were isolated from the aseptically collected pine weevil frass. Microbial produced volatile organic compounds (VOCs) were collected by solid phase micro extraction and analyzed by GC-MS after cultivating them on weevil frass broth. The major VOCs were tested against pine weevils using a multi-choice olfactometer. Ewingella sp., Mucor racemosus, Penicillium solitum, P. expansum, Ophiostoma piceae, O. pluriannulatum, Debaryomyces hansenii and Candida sequanensis were identified as abundant microbes. Styrene, 6-protoilludene, 1-octene-3-ol, 3-methylanisole, methyl salicylate, 2-methoxyphenol and 2-methoxy-4-vinylphenol were the VOCs of persistently isolated microbes. In behavioral bioassay, methyl salicylate, 3-methylanisole and styrene significantly reduced the attraction of pine weevils to their host plant volatiles. Heterobasidion spp. are severe pathogenic fungi of conifers that cause root and butt rot in plants. Bacterial isolates were tested for the antagonistic activity against fungi on potato dextrose agar. Bacillus subtilis strains significantly inhibited the growth of H. annosum and H. parviporum. Styrene is an industrial chemical used for making polymeric products, currently produced from fossil fuel. A strain of Penicillium expansum isolated from pine weevil frass was investigated for the production of styrene using forest waste. Grated pine stem bark and mature oak bark supplemented with yeast extract produced greater amounts of styrene compared to potato dextrose broth.
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| 2. |
- Ghisbain, Guillaume, et al.
(författare)
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A worthy conservation target? Revising the status of the rarest bumblebee of Europe
- 2021
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 14:5, s. 661-674
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Tidskriftsartikel (refereegranskat)abstract
- Against the context of global wildlife declines, targeted mitigation strategies have become critical to preserve what remains of biodiversity. However, the effective development of conservation tools in order to counteract these changes relies on unambiguous taxonomic determination and delineation.In this study, we focus on an endemic bumblebee species recorded only from the highest altitudes of the Sierra Nevada (Spain), Bombus reinigiellus (Rasmont, 1983). The species has the smallest range of any European bumblebee, along with a restricted diet and an inability to disperse because of its isolated montane distribution, making it an appropriate conservation target. However, through an integrative taxonomic approach including genetics, morphometrics and semio-chemistry, we demonstrate the conspecificity of this taxon with one of the most common and widespread bumblebee species of Europe, Bombus hortorum (L. 1761). We assign a subspecies status to this endemic taxon (Bombus hortorum reinigiellus comb. nov.) shown to be different in colour and morphology but also in wing shape and relative wing size compared to the other conspecific subspecies.Following our taxonomic revision, we reassessed the IUCN conservation status of Bombus hortorum both at the continental and Spanish scale. We then propose how historic climatic oscillations of the last Ice age could explain such a phenotypic divergence in a post-glacial refugium and highlight the critical role of establishing unambiguous taxonomic revision prior to any conservation assessment.
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| 3. |
- Lindmark-Henriksson, Marica, et al.
(författare)
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Transformation of alpha-pinene using Picea abies suspension culture
- 2003
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 66:3, s. 337-343
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Tidskriftsartikel (refereegranskat)abstract
- alpha-Pinene, both as the pure enantiomers and as the racemate, was transformed mainly to trans-verbenol by treatment with a Picea abies suspension cell culture. These reactions were followed by a slow transformation of the verbenol to verbenone, which was not transformed further. trans-Pinocarveol, myrtenol, cis-verbenol, and alpha-terpineol were byproducts of intermediate abundance. When subjected to the action of the suspension culture, cis-verbenol was not only transformed to verbenone but also isomerized to trans-verbenol. The transformation of alpha-pinene was fast, and the products were detected within one minute. The absolute configuration of the major products corresponded to that of the starting alpha-pinene enantiomer
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| 4. |
- Lindmark Henriksson, Marica, et al.
(författare)
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Transformation of terpenes using a Picea abies suspension culture
- 2004
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 0168-1656 .- 1873-4863. ; 107:2, s. 173-184
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Tidskriftsartikel (refereegranskat)abstract
- When subjected to a Picea abies suspension cell culture, beta-pinene, either one of the pure enantiomers or the racemate, was transformed mainly to trans-pinocarveol along with the minor products myrtenol, alpha-terpineol, pinocarvone, myrtenal and cis-pinocarveol. The absolute configuration of the major products corresponded to that of the starting beta-pinene enantiomer. Some of the primary transformation products, i.e. (1S)-cis- and (1S)-trans-pinocarveol, (1R)-myrtenol and (4S)-alpha-terpineol, were also tested as substrates of the P. abies suspension culture. They reacted more slowly than beta-pinene but, except for (4S)-alpha-terpineol, they were all transformed. Thus, (1R)-myrtenol was converted into both (1R)-myrtenal and (1R)-myrtanol, whereas (1S)-trans-pinocarveol was converted into (1S)-pinocarvone. (4R)-Limonene was slowly transformed by the suspension culture into limonene-(1,2)-epoxide as the major product, with carveol, perillyl alcohol and 1,8-cineole as minor products. Autoxidation of terpenes in cell-free nutrient medium was investigated in detail. alpha-Pinene and beta-pinene were both autoxidized to a certain extent, while limonene remained unaffected. The rate of the autoxidation was more than one order of magnitude slower than that of the biotransformation. Moreover, different products were formed by autoxidation than by biotransformation.
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| 5. |
- Lundborg, Lina, 1986-
(författare)
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Effects of methyl jasmonate on chemical defenses of conifer seedlings in relation to feeding by Hylobius abietis
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The chemical elicitor methyl jasmonate (MeJA) could replace insecticides in Europe and Asia for protection of young conifers against the pine weevil (Hylobius abietis). This thesis mainly focuses on the effects of MeJA treatment on chemical defenses of conifers from seedling batches with documented field resistance. Tissues of three pine species and one spruce species, with various treatments, were here extracted in hexane, whereafter volatile contents of tissues were separated and analyzed by 2D GC-MS.Induced responses of seedlings of Maritime pine (Pinus pinaster) and Monterey pine (Pinus radiata) to the folivore pine processionary (Thaumetopoea pityocampa), and the phloem-feeder H. abietis, have been studied. Amounts of mono- and sesqui-terpenes (and also non-volatile resin) in conifer tissues (needles and phloem) were less induced by T. pityocampa than by H. abietis.The MeJA-treated seedlings of Scots pine (Pinus sylvestris) changed their composition of phloem monoterpenes (induction of (-)-β-pinene), and were better protected in field than the seedlings of Norway spruce (Picea abies), which increased their total amounts of monoterpenes. Orientation bioassays with H. abietis showed deterrent effects of (-)-β-pinene, (+)-3-carene, (-)-bornyl acetate and 1,8-cineole. Conversely, (-)-α-pinene (induced in P. abies but not in P. sylvestris) was non-deterrent.MeJA-treated seedlings fed on by H. abietis contained higher amounts of the H. abietis antifeedant 2-phenylethanol, in tissues and emissions. Phloem of control seedlings instead induced the (+)-α-pinene, which is one of the enantiomers of the H. abietis attractant α-pinene.In response to MeJA treatment, the relative amounts of the (+)-α-pinene increased in the phloem of P. radiata, while it decreased in P. pinaster phloem. The preference of H. abietis in the field for P. radiata before P. pinaster may be explained by these changes in enantiomers of the H. abietis attractant α-pinene.
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| 6. |
- Valterova, Irena, et al.
(författare)
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Male bumble bee pheromonal components in the scent of deceit pollinated orchids; unrecognized pollinator cues?
- 2007
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Ingår i: Arthropod-Plant Interactions. - : Springer Science and Business Media LLC. - 1872-8855 .- 1872-8847. ; 1:3, s. 137-145
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Tidskriftsartikel (refereegranskat)abstract
- The pollination of the non-rewarding Orchis pauciflora was studied. The most abundant visitors of O. pauciflora were B. terrestris queens. The fragrance of O. pauciflora inflorescence was dominated by a sesquiterpene (E)-beta-farnesene. (E,E)-alpha-Farnesene, (E)-2,3-dihydrofarnesol, geranylcitronellol, and the monoterpenes limonene and 1,8-cineol were found among less abundant constituents. The sesqui- and diterpenes detected in O. pauciflora fragrance are frequent constituents of male marking pheromones of many bumble bee species. Enantioselective analysis of O. pauciflora scent and B. terrestris male marking pheromone revealed the presence of the (S)-isomer of (E)-2,3-dihydrofarnesol in both samples, and electrophysiological experiments showed that mainly the (S)-isomer activated the antennal receptors. In field experiments, O. pauciflora inflorescences were enriched with the main compound (E)-beta-farnesene resulting in significantly increased pollinia export. We here discuss the chemical similarities between orchid and bumble bees and whether the presence of bumble bee male pheromone components in O. pauciflora fragrance increases its fitness.
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| 7. |
- Wallin, Erika A., 1985-, et al.
(författare)
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Stereochemistry of two pheromonal components of the bumblebee wax moth, Aphomia sociella
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- The bumblebee wax moth, Aphomia sociella, is a parasite of bumblebees. In this species, males produce sexual pheromone to attract females, while females produce an aphrodisiac pheromone that initiates male courtship. Both pheromones contain 6,10,14-trimethylpentadecan-2-one (TMPD-one) and the corresponding alcohol, 6,10,14-trimethylpentadecan-2-ol (TMPD-ol) in sex specific quantities. Male sex pheromone consists of 7 components with TMPD-one as a minor one and traces of TMPD-ol. In female aphrodisiac pheromone, TMPD-ol is the major component, while TMPD-one is present in traces. Here we report on the absolute configuration of TMPD-one in male sex pheromone and TMPD-ol in female aphrodisiac pheromone of A. sociella. The configuration was determined from GC/MS of prepared (S)-acetoxypropionyl esters of TMPD-ol. TMPD-one was first reduced to the alcohol that was then derivatized with (S)-acetoxypropionyl chloride. The GC/MS data of obtained diastereoisomers were compared with synthetic standards. The absolute configuration of TMPD-one in the male pheromone was (6R,10R). The configuration of TMPD-ol in the female pheromone was (2R,6R,10R). Electrophysiological experiments showed that TMPD-one and TMPD-ol are perceived by both sexes. The synthetic standards of naturally produced stereoisomers elicited higher responses than mixtures of all stereoisomers.
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| 8. |
- Zhao, Tao
(författare)
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Conifer chemical defense : Rugulation of bark beetle colonization and pheromone emission
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Terpenes and phenols are of importance in conifer defense against insects and pathogens. Knowledge about tree chemical defense is vital for developing practical methods to maintain healthy forests. With the aims of characterizing the defensive chemical induction in Norway spruce Picea abies and demonstrating its ecological function to spruce bark beetle Ips typographus, we measured the terpenoid and phenolic content in the bark of mature Norway spruce trees suffering windstorm, inoculated with Ceratocystis polonica, or treated with methyl jasmonate (MeJA), and investigated the colonization and pheromone emission of I. typographus. All three stressors altered the chemical profile in the bark of Norway spruce. Trees damaged by windstorm had lower proportions of (+)-3-carene and two unidentified stilbenes, and a higher taxifolin glycoside content than trees without apparent windstorm damage; C. polonica inoculation induced extremely strong quantitative terpene accumulation in the wound reaction zone, but only increased the levels of (+)-3-carene, sabinene and terpinolene in the bark near the reaction zone; MeJA treatment generally elicited quantitative terpene accumulation, but the induction differed extensively between individual trees. In addition, logs from MeJA-treated tree showed much stronger wounding response compared to control logs. The chemical profile of Norway spruce affected the colonization and pheromone emission of I. typographus. In response to fungal inoculation, terpene present in the reaction zone inhibited the colonization of I. typographus in a dose-dependent manner. Host defense elicited by MeJA treatment reduced emissions of 2-methyl-3-buten-2-ol and (S)-cis-verbenol, the two key aggregation pheromone components of I. typographus, and altered the ratio between the two components.
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