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- Lyytikäinen-Saarenmaa, Päivi, et al.
(författare)
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Predicting pine sawfly population densities and subsequent defoliation with pheromone traps
- 2001
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Ingår i: INTEGRATED MANAGEMENT AND DYNAMICS OF FOREST DEFOILIATING INSECTS, PROCEEDINGS. ; 277, s. 108-116
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Field in Finland to develop a monitoring and prediction trials were conducted from 1989 to 1993 method using pheromone traps for European pine sawfly (Neadiprion sertifer Geoffr.) population densities and needle defoliation. Three traps per site were baited with 100 mug of(2S,3S,7S) - 3,7 - dimethyl - 2 - pentadecyl acetate (diprionyl) at sites representing advanced pine stands. The number of overwintering eggs per sample branch was used to evaluate the effectiveness of using pheromone traps to estimate sawfly populations. The relationships between the number of males in traps, the number of eggs per branch in the subsequent generation, and the number of needle-year classes after the subsequent growing season were highly correlated. The risk threshold for moderate to heavy defoliation was around 1,000 males/trap. Our results suggest that after some minor improvements, a pheromone-based monitoring system for the European pine sawfly would provide an effective tool for integrated pest management programs and successful forest management in coniferous pine-dominated forests.
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- Berglund, Per, et al.
(författare)
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Enantiorecognition of Chiral Acids by Candida rugosa Lipase : Two Substrate Binding Modes Evidenced in an Organic Medium
- 2001
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Ingår i: Applied Biocatalysis in Speciality Chemicals and Pharmaceuticals. - : American Chemical Society (ACS). - 0841236798 ; 776, s. 263-273
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Konferensbidrag (refereegranskat)abstract
- We have identified the existence of different modes of binding the enantiomers of 2-methyl-branched carboxylic acids to a lipase active site by rational substrate engineering. Similar to hydrolysis, previously investigated, we have now evidence for differential binding modes in the Candida rugosa lipase-catalyzed esterifications in cyclohexane. The relevance of considering two different binding modes to understand lipase enantiorecognition is demonstrated by introducing bulky substituents on a chiral carboxylic acid which impose a different orientation of the substrate acyl chain in the active site of Candida rugosa lipase. With this substrate engineering approach based on molecular modeling it is thus possible to markedly alter the enantioselectivity of the lipase. Examples from hydrolysis and new results from esterifications in an organic solvent are presented and discussed.
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- Hedenström, Erik, et al.
(författare)
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Synthesis and lipase catalysed stereoselective acylation of some 3-methyl-2-alkanols, identified as sex pheromone precursors in females of pine sawfly species
- 2002
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Ingår i: Journal of The Chemical Society, Perkin Transactions 1. - : Royal Society of Chemistry (RSC). - 1472-7781. ; 2002:15, s. 1810-1817
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Tidskriftsartikel (refereegranskat)abstract
- Several 3-methylalkan-2-ols precursors to sex pheromones of Diprion pini, Gilpinia pallida, Gilpinia frutetorum, Diprion nipponica, Macrodiprion nemoralis and Microdiprion pallipes were synthesised as stereoisomeric mixtures in moderate to good yields. The key reaction sequence in the syntheses was the ring opening of either cis- or racemic trans-epoxybutane using a higher order cyanocuprate as nucleophile followed by a highly efficient lipase catalysed stereoselective acylation of the obtained 3-methylalkan-2-ol. The biologically active species specific stereoisomer was synthesised as a single stereoisomer in high stereoisomeric purity, as one in a mixture of two or as one of four stereoisomers when the appropriate 3-methylalkan-2-ol was stereoselectively acylated using a Pseudomonas sp. lipase as catalyst.
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