Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Development of a multiplex DNA-based traceability tool for crop plant materials
    Voorhuijzen, M.M. ; Dijk, J.P. van; Prins, T.W. ; Hoef, A.M.A. van; Seyfarth, R. ; Kok, E.J. - \ 2012
    Analytical and Bioanalytical Chemistry 402 (2012)2. - ISSN 1618-2642 - p. 693 - 701.
    rice oryza-sativa - basmati rice - wheat - fragrance - gene - pcr - adulteration - bread
    The authenticity of food is of increasing importance for producers, retailers and consumers. All groups benefit from the correct labelling of the contents of food products. Producers and retailers want to guarantee the origin of their products and check for adulteration with cheaper or inferior ingredients. Consumers are also more demanding about the origin of their food for various socioeconomic reasons. In contrast to this increasing demand, correct labelling has become much more complex because of global transportation networks of raw materials and processed food products. Within the European integrated research project ‘Tracing the origin of food’ (TRACE), a DNA-based multiplex detection tool was developed—the padlock probe ligation and microarray detection (PPLMD) tool. In this paper, this method is extended to a 15-plex traceability tool with a focus on products of commercial importance such as the emmer wheat Farro della Garfagnana (FdG) and Basmati rice. The specificity of 14 plant-related padlock probes was determined and initially validated in mixtures comprising seven or nine plant species/varieties. One nucleotide difference in target sequence was sufficient for the distinction between the presence or absence of a specific target. At least 5% FdG or Basmati rice was detected in mixtures with cheaper bread wheat or non-fragrant rice, respectively. The results suggested that even lower levels of (un-)intentional adulteration could be detected. PPLMD has been shown to be a useful tool for the detection of fraudulent/intentional admixtures in premium foods and is ready for the monitoring of correct labelling of premium foods worldwide.
    Geurende gewassen
    Hoffman, M.H.A. - \ 2011
    ornamental plants - woody plants - ornamental herbaceous plants - ornamental bulbs - fragrance - organoleptic traits - organolepsis - experiential value - emotions - well-being
    Use of new generation single nucleotide polymorphism genotyping for rapid development of near-isogenic lines in rice
    Boualaphanh, C. ; Daygon, V.D. ; Calingacion, M.N. ; Sanitchon, J. ; Jothityangkoon, D. ; Mumm, R. ; Hall, R.D. ; Fitgerald, M.A. - \ 2011
    Crop Science 51 (2011)5. - ISSN 0011-183X - p. 2067 - 2073.
    oryza-sativa l. - fragrance - metabolomics - populations - phenotypes - varieties - tomato - marker - grain - gene
    Studies aimed at determining gene function or identity are greatly facilitated by introgression lines and phenotyping tools. However, developing introgression lines can take six to eight generations to reach the desired level of background purity and homozygosity. The objective of this study was to use new generation genome-wide single nucleotide polymorphism (SNP) genotyping, along with a molecular marker for the allele of interest, and a relevant phenotyping tool, to develop research populations with just four generations of backcrossing. Two populations were created for future research on aroma in rice (Oryza sativa L.): one derived from two indica parents and the other from one indica and one tropical japonica parent. The same recurrent parent was used for both populations. Single nucleotide polymorphism genotyping of BC4F2 progeny selected previously on the basis of either a marker for fragrance or the presence of the fragrant compound and on the basis of morphological similarity to the recurrent parent showed that donor introgression ranged from
    PPO gaat leliegeur wetenschappelijk bekijken (interview met Hans Kok)
    Dwarswaard, A. ; Kok, B.J. - \ 2010
    BloembollenVisie 2010 (2010)190. - ISSN 1571-5558 - p. 68 - 68.
    lilium - lelies - rassen (planten) - cultivars - plantenveredeling - rassenproeven - welriekendheid - organoleptische kenmerken - geurstoffen - verzwakking - lilium - lilies - varieties - cultivars - plant breeding - variety trials - fragrance - organoleptic traits - odours - attenuation
    De geur van met name Oriëntale lelies en OT-hybriden is voor menigeen reden deze lelies niet te kopen. Japans onderzoek zette PPO-onderzoeker Hans Kok op het spoor van een stof die mogelijk kan helpen om de geursterkte substantieel te verminderen. Kok zou het fantastisch vinden als het werkt. "Dat zal de marktkansen flink vergroten."
    Snijbloemen versterken positieve gevoelens en stemmingen : wetenschappelijk onderzoek naar het effect van snijbloemen op de gemoedstoestand van de mens
    Vermeer, F. ; Mojet, J. ; Veggel, R.J.F.M. van; Koster, A.C. - \ 2009
    Zoetermeer : Produktschap Tuinbouw, afdeling Markt & Innovatie
    snijbloemen - visuele prikkels - stimulatie - emoties - plezier - kleur - welriekendheid - verkoopbevordering - consumentengedrag - marketing - belevingswaarde - gevoeligheid - cut flowers - visual stimuli - stimulation - emotions - enjoyment - colour - fragrance - sales promotion - consumer behaviour - marketing - experiential value - sensitivity
    Onderzoek van Wageningen UR naar de invloed van snijbloemen op gevoelens en stemmingen toont postieve resultaten. Dit biedt veel kansen voor reclame- en voorlichtingscampagnes, maar ook voor verkoopgesprekken en toepassingsmogelijkheden in bijvoorbeeld restaurants
    Relaties tussen planteigenschappen en welbevinden van mensen : literatuuronderzoek
    Hoffman, M.H.A. - \ 2007
    Wageningen : Wageningen UR (Rapport / Plant Research International 146) - 33
    bloemen - sierplanten - welriekendheid - zintuiglijke waarneming - informatieverwerking - literatuuroverzichten - publicaties - databanken - informatiesystemen - invloeden - wetenschappelijk onderzoek - flowers - ornamental plants - fragrance - organolepsis - information processing - literature reviews - publications - databases - information systems - influences - scientific research
    Aangetoond is dat een groene omgeving (natuur, stedelijk groen, tuinen, kamerplanten, etc.) positief werken op het welbevinden van mensen. Minder bekend is welke specifieke relaties hieraan ten grondslag liggen; welke kleuren, geuren, vormen, geluiden, specifieke plantensoorten, etc.? Resultaat van een zoektocht in verschillende databases en internet naar specifieke relaties tussen planteigenschappen en welbevinden van mensen. Hierbij is gezocht naar wetenschappelijke publicaties in het groene, medische en cosmetische circuit
    Geurend sortiment verkoopt : maak de juiste keuze
    Hoffman, M.H.A. - \ 2007
    De Boomkwekerij 2007 (2007)14. - ISSN 0923-2443 - p. 10 - 11.
    plantenkwekerijen - sierplanten - overblijvende planten - welriekendheid - aroma - reuk - cultivars - rassen (planten) - nurseries - ornamental plants - perennials - fragrance - aroma - smell - cultivars - varieties
    De laatste jaren komt er meer erkenning voor de eigenschap 'geur' in sierplanten, die eigenschap is jarenlang miskend en verwaarloosd bij het selecteren van nieuwe cultivars. Planten die lekker ruiken hebben zonder twijfel een streepje voor op planten die niet geuren. Steeds vaker komen geuraanduidingen in catalogi en labels te staan. Met lijst van Top 10 geurende gewassen
    Geurende houtige gewassen en vaste planten
    Hoffman, M.H.A. - \ 2005
    Dendroflora 42 (2005). - ISSN 0374-7247 - p. 26 - 87.
    houtachtige planten als sierplanten - tuinplanten - organoleptische kenmerken - welriekendheid - zintuiglijke waarneming - taxa - soortenkeuze - rassen (planten) - beschrijvingen - geurstoffen - ornamental woody plants - bedding plants - organoleptic traits - fragrance - organolepsis - taxa - choice of species - odours - varieties - descriptions
    Plantengeuren spelen een belangrijke rol in ons leven. Desondanks is de eigenschap geur jarenlang miskend en verwaarloosd bij de selectie van nieuwe cultivars. PPO Bomen deed onderzoek naar geur bij een groot aantal boomkwekerij-gewassen. In dit artikel een overzicht van geurige gewassen voor de tuin
    (+)-Aromadendrene as chiral starting material for the synthesis of fragrances and pheromones
    Lamers, Y.M.A.W. - \ 2003
    Wageningen University. Promotor(en): Aede de Groot, co-promotor(en): J.B.P.A. Wijnberg. - [S.I.] : S.n. - ISBN 9789058088338 - 110
    synthese - welriekendheid - feromonen - stereochemie - enantiomeren - synthesis - fragrance - pheromones - stereochemistry - enantiomers

    (+)-Aromadendrene ( 1 ) is a sesquiterpene present in the distillation tail of the oil of Eucalyptus globulus . This distillation tail is commercially available in large quantities at low price and is an interesting starting material for the synthesis of other chiral products. A fair amount of research has already been carried out on aromadendrene (Chapter 1). This research was mainly focussed on transformation and isomerization of the double bond, opening of the cyclopropane ring, oxidations of derivatives of aromadendrene, and rearrangement of the aromadendrene skeleton.

    In this thesis, the possibilities to use aromadendrene for other synthetic strategies were explored and the first interest was the development of an economically feasible route toward the fragrance compound 167 (Chapter 2). Ledene epoxide ( 154 ), easily available from aromadendrene, was selected as the starting material for this route, and rearrangements of thisb-epoxide were investigated. The formation of products with the cubebane ( 159 ) and cadinane skeleton ( 160 ) indicates that bridgehead carbocations are the prefered intermediates in these rearrangements. From these experiments it was concluded that the synthetic route toward 167 as published by Gijsen is the most efficient route known so far.

    Scheme 1

    Synthesis of guaiane-type compounds by opening the cyclopropane ring in aromadendrene has proven to be difficult. In Chapter 3 it was shown that the conversion of isoledene ( 107 ), a double bond isomer of aromadendrene, to compounds with the guaiane skeleton can be performed in a fairly easy way. The synthesis of the blue colorant guaiazulene ( 35 ) in 22% isolated yield over two steps from isoledene is an improvement of the existing methods for the dehydrogenation with sulfur of aromadendrane or guaiane type sesquiterpenes.

    Figure 1

    A number of guaianes, for example the cyclic ethers 198 and 200 , were synthesized from isoledene epoxide ( 193 ). Isoledene epoxide can be converted by (Lewis) acid to a stabilized cyclopropylcarbinyl cation, which undergoes opening of the cyclopropane ring to a guaiane skeleton. When no water is present during the reaction, ether 198 is obtained and the presence of water leads to formation of ether 200 . Several functionalized derivatives of 198 have been prepared. These compounds were tested for their use as fragrances, but unfortunately they were not suitable as such.

    Scheme 2

    A relatively new method for crop protection is the use of pheromone traps for monitoring or mass trapping of insects. By using these pheromone traps, the amount of insecticides often can be reduced considerably, which is more environmentally friendly and more selective. In Chapter 4 a method is described for the conversion of aromadendrene to methyl-branched linear pheromones. These pheromones ( R )-224 , ( S )-298 , and meso -306 were all synthesized from the common linear intermediate 290 . One of the key steps in the synthesis of 290 is the Baeyer-Villiger reaction of bromide 284 , and opening of the lactone ring in a one-pot reaction to give the hydroxy ester 286 . Via a Grob fragmentation using NaOEt in the presence of NaBH 4 and catalytic hydrogenation, 286 was then converted to compound 290 .

    In Chapter 5 investigations towards the synthesis of dimethyl-branched linear pheromones have been described. It was shown that it is possible to convert aromadendrene to the dimethyl-branched linear intermediate 308 , following a route similar to the one described in Chapter 4.

    Scheme 3

    Molecular regulation of plant monoterpene biosynthesis in relation to fragrance
    Tamer, M.K. El - \ 2002
    Wageningen University. Promotor(en): A.G.J. Voragen; H.J. Bouwmeester; J.P. Roozen. - S.l. : S.n. - ISBN 9789058087522 - 151
    citrus limon - citrus sinensis - monoterpenen - welriekendheid - biosynthese - regulatie - moleculaire biologie - plantensamenstelling - genetische modificatie - citrus limon - citrus sinensis - monoterpenes - fragrance - biosynthesis - regulation - genetic engineering - molecular biology - plant composition

    Citrus belongs to an important economical group of crops. Fruits have a distinguished and pleasant taste partly due to the presence of terpenes. Furthermore, these terpenes potentially play a role in the resistance against pathogens such as insects and fungi. The aim of this thesis was therefore to study the regulation of terpene biosynthesis in Citrus limon L. Burm. Therefore, monoterpene synthase cDNAs from Citrus limon L. Burm. peel were isolated by a cDNA library-screening approach and to identify specific domains, and possibly amino acids, involved in product specificity within the active site of these enzymes. In addition, we aimed at investigating factors that might positively contribute to the regeneration of transgenic Citrus sinensis (L.) Osbeck cv. Valencia Late plants. Because transforming Citrus was not practical, we aimed at studying the odor effects of transforming a model plant, Nicotiana tabacum , with the isolated Citrus limon monoterpene synthases.

    In chapter 2, the isolation, expression and characterization of four new cDNAs belonging to the terpene synthase b sub-family ( tpsb ) family (Bohlmann et al., 1998) and coding for monoterpene synthases in Citrus limon L. Burm . has been described in detail. A random sequencing approach was applied to a cDNA library from mRNA isolated from the peel of a young developing fruit. These monoterpene synthase cDNAs were isolated and all four cDNAs could be functionally expressed in E. coli after removal of their plastid targeting signals. The main products of the enzymes in assays with geranyl diphosphate (GDP) as substrate were (+)-limonene (two cDNAs), (-)-β-pinene andγ-terpinene and these enzymes were named Cl(+)LIMS1, Cl(+)LIMS2, Cl(-)βPINS and ClγTS, respectively.

    In chapter 3, the functional differences which were present within the domains of the monoterpene synthases and leading to product specificity in the enzymatic catalysis, have been studied. Domain swapping experiments were conducted as well between Cl(-)βPINS and ClγTS as between Cl(+)LIMS2 and ClγTS . We showed that within the same putative C-terminal structural domain of monoterpene synthases, a region comprising 200 amino acids, of which 41 are different between Cl(-)βPINS and ClγTS, determines the specificity for the formation ofβ-pinene orγ- terpinene, respectively, while another region localized further downstream is required for a chimeric enzyme to yield products with the same ratio as in the wild type ClγTS. For Cl(+)LIMS2, both domains together appear to be sufficient for its enzyme specificity, but probably due to the low homology with ClγTS, many chimeric enzymes were inactive.

    In order to find factors that might improve the transformation efficiency of Citrus sinensis (L.) Osbeck cv. Valencia Late, the interactive effects within the regeneration of Citrus sinensis have been studied (Chapter 4). The latter was focused on the influence of the initial germination medium, of the explant type (source) and of the regeneration medium on shoot regeneration. Results show that the germination on MS30 (Murashige & Skoog, 1962) and the regeneration on NNIII (Nitsch & Nitsch, 1969) containing a 20:1 cytokinin: auxin ratio supplied with the riboside form of the benzyl amino purine cytokinin, are essential for an efficient induction of shoot regeneration. In addition, hypocotyl-derived shoot regenerants incubated on NNRtVIII (Nitsch & Nitsch based medium) showed better rooting than epicotyl-derived shoot regenerants and incubation on other media tested.

    Finally, with the help of a human panel, the floral fragrance effect of transforming Nicotiana tabacum either together with the Cl(+)LIMS1, Cl(-)βPINS and ClγTS genes, or singly with the Cl(-)βPINS gene has been investigated (Chapter 5). In a triangle experimental design, the panel was able to discriminate significantly between the smell of a transgenic plant and a wild type plant. However, a descriptive panel had difficulties to generate accurate sensory descriptors for smells, and to reach consensus on the precise meaning of chosen attributes in a predetermined small number of panel sessions.

    Nevertheless, this thesis illustrates an example where the combination of molecular biology, cell biology and biochemistry, and sensory analysis offers an integrated approach as a first step in trying to unravel the world of plant fragrance emission and perception.

    Ambergris fragrance compounds from labdanolic acid and larixol
    Bolster, M.G. - \ 2002
    Wageningen University. Promotor(en): Æ. de Groot; B.J.M. Jansen. - S.l. : S.n. - ISBN 9789058086662 - 214
    diterpenen - welriekendheid - aromatische verbindingen - biosynthese - chemische eigenschappen - oxidatie - biologische eigenschappen - diterpenes - fragrance - aromatic compounds - biosynthesis - chemical properties - oxidation - biological properties

    Since ancient times, ambergris has been one of the most highly valued perfumery materials. Ambergris is a metabolic product of the spermwhale ( Physeter macrocephalus L.), which accumulates as concretions in the gut. (-)-AmbroxÒ, the commercially most important constituent of natural ambergris, is recognized as the prototype of all ambergris odorants. For this reason, various synthetic routes to (-)-AmbroxÒand its racemate have been developed, preferrably starting from cheap, abundantly available natural labdanes. Sclareol is nowadays the industrially used starting material for the preparation of (-)-AmbroxÒ. Labdanolic acid and larixol are both easily and abundantly available from labdanum gum of Cistus ladaniferus L. ("Rock-rose") and turpentine of the Larix decidua , respectively, but have found little use as starting material in syntheses of Ambergris odour compounds. In this thesis new chemistry in that field is described.

    From the acetate of labdanolic acid short procedures are developed for the synthesis of AmbroxÒ. Also a standard method has been developed for the oxidation of the side chain of several labdanes. Generally good to high yields of single products can be obtained using anhydrous potassium permanganate in the presence of a phase-transfer catalyst. In this way larixol can be converted into suitable synthons for the synthesis of several Ambrox-like compounds. 6a-hydroxy Ambrox can be considered to be a key intermediate in such syntheses and conversions of larixol into this intermediate are described. From 6a-hydroxy Ambrox a number of simple Ambrox derivatives have been synthesized. By heating with acid a mixture was formed consisting ofD5- andD6-Ambroxene, which both are pleasant smelling.D5-Ambroxene was produced in a more selective way by elimination of methanesulfonic acid from the corresponding mesylate of 6a-hydroxy Ambrox. A selective synthesis ofD6-Ambroxene proved to be more difficult and laborious. Several approaches were investigated, and ultimately the one via ringclosure of an allylic alcohol proved to give good results. It turned out that this new approach could not be extended to the selective synthesis of six-membered cyclic ethers, e.g.D6-Ambra oxides. In the latter case, elimination of the 6b-hydroxyl group to the correspondingD6,8-dienes was observed as the major reaction.

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