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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Studies on bile and brain specializations in uranoscopid fish (Perciformes: Uranoscopidae)

Hsu, Jumg-chen 20 August 2010 (has links)
Stargazers (Uranoscopidae) have two specialized characters- large volume of bile and a small-size brain. To explain why stargazers need large volume of bile, two hypotheses were proposed: (1) a function of the bile of stargazers is acting as the sex pheromone, and (2) bile enhances calcium uptake efficiency. The brain volume was measured, and the volumes of each part of the brain were also measured. The elementary investigations indicate that the stargazers have larger bile volume ratio and smaller brain weight ratio than other fishes reported in the present studies. The bile volumes are no significant difference between the female stargazers and the male stargazers, the bile volumes showed no monthly difference. Besides, the number of olfactory epithelium and the neuron density of the telencephalon in stargazers were not more than other fishes, the function of sex pheromone of bile can not be confirmed. The cranium hardness, bone density, and calcium content in stargazers are significantly more than other fishes. Most fish uptake calcium by the gill and the intestine from seawater or food. However, stargazers often hide in the sand and wait for the prey for most of the time, less water flow through the gills are expected. Therefore stargazers possibly uptake calcium through the intestine. Efficiency of the bile to aid calcium uptake has to be examined by experiments. The paraffin histology has been taken in various parts of the brain. Crista cerebelli is the center for sensing mechanical vibration; the volume of stargazer¡¦s crista cerebelli is higher than other fishes. Stargazers have large saccular otolith compare to the whole brain. Studies on the lateral line and acoustic sense of stargazers are new research topics. Furthermore, decrease in brain size in stargazers is for the purpose of reducing the oxygen consumption, so as to hiding in the sand. Stargazers are one of the fisheries species on western Taiwan coast. However there are very few studies on the stargazers in Taiwan; we should understand more about them in order to protect and consume the stargazers in a better way.
2

Ecological and behavioral factors associated with monitoring and managing pink hibiscus mealybug (Hemiptera: Pseudococcidae) in the southern US

Vitullo, Justin Matthew 21 July 2009 (has links)
The pink hibiscus mealybug (PHM), Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae) was investigated with regard to damage caused to hibiscus by feeding, dispersal of nymphs, evaluation of management tactics, and the use of sex pheromone based monitoring in southern Florida from 2005 to 2008. Understanding the ability of PHM to locate and colonize new hosts, and the response of hosts is essential to optimized monitoring and management strategies. Investigation of the onset and severity of PHM feeding symptoms by Hibiscus rosa-sinensis L. showed that severity of symptoms differed among cultivars and that PHM were found on plants that did not exhibit feeding symptoms. Aerially dispersing PHM were predominantly first instars. Dispersal occurred with a diel periodicity that peaked between 14:00 and 18:00 h and was significantly influenced by mean wind speed. Initial infestation with 5, 10, or 20 PHM adult females had no significant affect on the number of dispersing individuals captured from hibiscus plants and PHM were captured at 50 m from infested source plants. The effects of mating disruption, the insecticide (dinotefuran), the parasitoid, Anagyrus kamali (Moursi), and the predator, Cryptolaemus montrouzieri (Mulsant) on PHM on hibiscus plants in screened field cages were evaluated. The total number of mealybugs captured in sticky band and pheromone traps during the study was reduced by dinotefuran and the predator. At the end of the study, the number of nymphs recovered from hibiscus terminals was reduced by the dinotefuran, predator and parasitoid treatments. Field experiments showed that the time of day during which male PHM were captured in pheromone traps in May and September was crepuscular, with most captures occurring from 18:00 to 21:00 h. Significantly more males were captured in traps placed in non-host trees at an elevation of 2 m above the ground than 6 m, and more males were captured in traps placed within host plants than in those 3 m upwind. Pheromone traps placed in hibiscus treated with soil applied dinotefuran or left untreated captured equal numbers of males during the 3 wk prior to treatment and during the 12 wk after treatment. Release of parasitoids at residential sites did not have a significant effect on the total number of males captured in sex pheromone traps over 18 mo. The number of mealybugs found at both parasitoid release and untreated sites were highly variable and corresponded with males captured in sex pheromone traps, as high and low levels of mealybugs corresponded with high and low levels of males captured. The number of males captured in pheromone traps during a two week survey at residential sites in May were a strong predictor of subsequent captures in 2006 (r2 = 0. 712), but not 2007 (r2 = 0.019). The relationship between PHM populations and males captured in sex pheromone traps was influenced by a multitude of factors that can impact the ability of traps to accurately reflect populations at a given location. Pheromone traps have the potential to provide meaningful information towards monitoring and mitigating risk from PHM. The contributions of this dissertation towards optimizing PHM sex pheromone monitoring, as well as facets of PHM monitoring that have yet to be resolved are discussed. / Ph. D.
3

Surveillance of grape berry moth, Paralobesia viteana Clemens (Lepidoptera: Tortricidae), in Virginia vineyards

Jordan, Timothy Augustus 04 April 2014 (has links)
My research addressed pheromone lure design and the activity of the grape berry moth, Paralobesia viteana, flight and infestation across three years of study. In my lure evaluations, I found all commercial lures contained impurities and inconsistencies that have implications for management. First, sex pheromone concentration in lures affected both target and non-target attraction to traps, while the blend of sex pheromones impacted attraction to P. viteana. Second, over the duration of study, 54 vineyard blocks were sampled for the pest in and around cultivated wine grape in Virginia. The trapping studies indicated earliest and sustained emergence of the spring generation in sex pheromone traps placed in a wooded periphery. Later, moths were detected most often in the vineyard, which indicated that P. viteana emerged and aggregated in woods prior to flying and egg-laying in vineyards. My research supports use of woods and vineyard trap monitoring at both the height of 2 meters and in the periphery of respective environments. These conditions should improve grower efficiency when using trapping as a tool. Cluster infestation was assessed relative to vineyard growth stage and location in the vineyard. My results are in agreement with historical studies that suggest infestation is highest in the periphery of vineyards. However, I found that infestation peaked at veraison before falling somewhat around pre-harvest. This indicated that growers should manage this pest prior to veraison, perhaps as early as budbreak, to prevent the insect from reaching damaging levels when the crop is more susceptible to loss. Lastly, by combining field-based data collection with remote climate and landscape monitoring, growers can achieve a greater level of surveillance of P. viteana. A mash up of remote and vineyard-based data can provide substantive pertinent information for management at both local and regional scales. If one grower identifies moth emergence, then growers nearby potentially can use that same information to initiate models to monitor development of the moth population in their own vineyard. This research complements the notion that the more a community shares information, the broader its applicability becomes to neighbors. / Ph. D.
4

Purification, Stereoisomeric Analysis and Quantification of Biologically Active Compounds in Extracts from Pine Sawflies, African Butterflies and Orchid Bees

Bång, Joakim January 2011 (has links)
Stereochemistry plays an important role in nature because biologically important molecules such as amino acids, nucleotides and sugars, only exist in enantiomerically pure forms. Semiochemicals carry messages, between the same species (pheromones) and between different species (allelochemicals). Both pheromones and allelochemicals can be used as environmentally friendly pest management. Many semiochemicals, i.e. behaviour modifying chemicals, consist of pure or well-defined mixtures of stereoisomers, where some of the other stereoisomers can be repellent. It is therefore important to be able to separate them to produce a synthetic pheromone in a mixture that is attractive. Pine sawflies are a family of insects that in some cases can be severe defoliators of conifer trees. Diprion pini, Diprion similis and Neodiprion sertifer are severe pests for these trees and have got the most attention in pine sawfly pheromone studies. The pheromone precursors are stored in the female body as long-chain secondary alcohols, which, when released, are esterified to acetates or propionates. The alcohols are chiral, and normally one of the stereoisomer is the main pheromone component, sometimes possible together with other stereoisomers as essential minor components. Bicyclus is a genus of African butterflies, and especially Bicyclus anynana has become a popular model for the study of life history evolution, morphology, mating choice and genetics. The wing pattern of Bicyclus differs depending on the season, with large eyespots during the rain-season and small or absent spots during the dry season.  Euglossa is one of the genera among the orchid bees in the Neotropics that does not produce its own pheromone. Instead, the males collect fragrances from orchids and other sources and store them in a pocket in their hind legs. Both Bicyclus and Euglossa use semiochemicals similar to pine sawflies, and thus can be analysed by the same methods. Pheromones and other semiochemicals in insects are often present in low amounts in a complex matrix, and purification of the sample before chemical analysis is often required. A common method is gradient elution on a solid phase silica column. Separation of stereoisomers can be achieved either by using a column with a chiral stationary phase (CSP) or with pre-column derivatisation using a column with an achiral stationary phase (ASP) or a combination of both, with mass detection as the dominant detection method. The purpose of this work has been to improve the purification method, find suitable methods to separate the stereoisomers of secondary alcohols, and to apply this on extracts of insects. By selecting the right fractions to collect during gradient elution the purification method was optimised. To reduce plasticizer contamination from ordinary columns, solid phase columns of Teflon or glass were used. For pre-column derivatisation of different chiral alcohols various acid chlorides were tested. For the pine sawfly pheromone precursors enantiopure (2S)-2-acetoxypropionyl chloride was the best choice. To separate some of the stereoisomers achiral 2-naphthoyl chloride was used. For derivatisation of 6,10,14-trimethylpentadecan-2-ol (R)-trans-chrysanthemoyl chloride was the best choice. The derivatised alcohols were separated on different columns, both chiral and non-chiral. Varian FactorFour VF-23ms was chosen as a general-purpose column, the Agilent HP-88 column was the best column with an ASP of those tested, and the Chiraldex B-PA column (CSP) was the only one that could separate all eight stereoisomers of derivatised 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol, and 3,7-dimethyltridecan-2-ol. To determine the stereoisomeric purity of standard solutions used in field experiments and extracts of different species of insects the optimised methods were applied. For extracts from B. anynana, Euglossa and Neodiprion lecontei this work describe the first determination of the stereochemistry of some of their semiochemicals. For the determination of the stereochemistry of chiral semiochemicals the methods for purification and separation presented herein have shown to be of great value. The results will hopefully contribute to a better understanding of the communication among insects, and ultimately to a more environmentally friendly pest control. / Många naturligt förekommande kemiska ämnen finns som två spegelbilder av varandra, ungefär som höger och vänster hand. Dessa kan ha helt olika egenskaper och det är därför viktigt att kunna separera dem. Insekter och andra djur använder olika doftämnen för att kommunicera med varandra, om det är inom samma art kallas de för feromoner. De kan bestå av ett ämne eller en blandning av flera. Dessa doftämnen kan man även använda för att på ett miljövänligt sätt bekämpa skadeinsekter. En fälla med syntetiskt feromon för en viss insekt lockar endast till sig den arten, medan alla andra är opåverkade. Eftersom dessa ämnen ofta finns som spegelbilder där kanske bara den ena är aktiv och den andra rent av frånstötande, måste man kunna separera dem för att framställa ett syntetiskt feromon som är attraktivt. Målet med detta arbete har varit att bestämma feromonet hos olika arter av tallsteklar som kan vara svåra skadedjur på tallskog. De metoder som tagits fram har även tillämpats på några arter av afrikanska fjärilar samt orkidébin från Centralamerika eftersom de använder snarlika doftämnen. Att få fram feromonet från en insekt är lite som att leta efter in nål i en höstack eftersom de ofta bara innehåller några miljarddels gram per individ. Provet behöver först renas, och en del av arbetet i det här projektet har gått ut på att ta fram en lämplig reningsmetod. Huvudfokus har dock varit på att ta fram metoder som kan separera och identifiera det eller de ämnen, och spegelbilder av dessa, som doftämnena består av. När lämpliga metoder tagits fram har extrakt av olika insektsarter analyserats. I några fall är det första gången som deras feromon bestämts i detalj. Resultaten kan förhoppningsvis bidra till en ökad kunskap om insekters sätt att kommunicera, och i slutändan till miljövänligare bekämpning av skadeinsekter.
5

Using sex pheromone and a multi-scale approach to predict the distribution of a rare saproxylic beetle

Musa, Najihah January 2012 (has links)
The European red click beetle, Elater ferrugineus L., is associated with wood mould in old hollow deciduous tree. As a result of severe habitat fragmentation caused by human disturbance, it is threatened throughout its distribution range. A new odour-based trapping method, which is very efficient in attracting males, was used in the present study to relate the occurrence of E. ferrugineus to the density of deciduous trees using a recently completed regional survey recording >120, 000 deciduous trees. Results showed that the occurrence of E. ferrugineus increased with increasing amount of large hollow and large non-hollow trees in the surrounding landscape. Quercus robur was found as an important substrate for E. ferrugineus and two groups of tree species (Carpinus betulus, Fagus sylvatica, Ulmus glabra, vs. Acer platanoides, Aesculus hippocastanum, Fraxinus excelsior and Tilia cordata) could be a complement to the existence of Quercus in sustaining the beetle’s population. E. ferrugineus responded to the density of Quercus at two different spatial scales, 327 m and 4658 m, suggesting that a multi-scale approach is important for studying the species. In conclusion, for conservation management, priority should be given to Quercus, and also to all deciduous trees in the genera listed above, regardless of the tree quality. The response showed by E. ferrugineus on the amount of substrate at two different scales indicates that using multi-scale approach in studying this particular species is the better option as single-scale approach may result in poor decision support.
6

The Scents of Nature : Identification and Synthesis of Bioactive Compounds Used in Insect Communication

Wallin, Erika January 2014 (has links)
Pest insects cause great financial losses in the forest and food industry every year. To fight these pests industries have used insecticides, which are sometimes harmful to nature and humans. One potential way of avoiding insecticides is the use of integrated pest management based on insect communication, which would offer species-specific methods for protecting forest and food resources. Insects use chemicals known as semiochemicals for both intra- and interspecies communication. By learning how insects use these semio-chemicals to talk to each other we can eavesdrop and mimic their communication for our benefit. One research area dealing with these questions is chemical ecology, which is an interdisciplinary area as knowledge in chemistry and biology is required. Collaborations between groups within and outside of Sweden are essential in order to make progress in this field of research. This thesis presents the identification and synthesis of semiochemicals from several insect species, most of which are considered to be pests. Synthesised compounds have been sent to collaboration partners around Sweden and Europe for biological evaluations. Studies of the African butterfly, Bicyclus anynana, have unravelled particular biological phenomena that may aid in the understanding of the Bicyclus genus, though recognizing individual species variation is crucial. In 2008 the putative male sex pheromone of B. anynana was determined to consist of three compounds: hexadecanal, (Z)-9-tetradecenol and 6,10,14-trimethylpentadecan-2-ol, and the specific stereoisomer for 6,10,14-trimethylpentadecan-2-ol has been determined in this thesis. The ratio of 6,10,14-trimethylpentadecan-2-ol and the corresponding ketone were investigated for seventeen Bicyclus species (including B. anynana) that live in overlapping regions in Africa. The stereochemistry was determined for most of the species and may provide a way to chemically distinguish them. The orchid bees, Euglossa spp, are important pollinators of many orchids in Central America. Insight about pollination and conservation of endangered orchid species may be possible by gathering more information about the Euglossa genus. Males of the Euglossa genus have pouch-like structures on their hind legs where they store compounds collected from their surroundings. 6,10,14-Trimethyl-pentadecan-2-one is a common component of leg extracts from Euglossa imperialis, E. crassipunctata and E. allosticta, the specific stereochemistry of which has been determined in this thesis. Another, different compound was found in high amounts in E. viridissima and its structure has been elucidated; several synthetic pathways are under investigation to obtain the target compound. Bed bugs (Cimex lectularius and C. hemipterus) are an ectoparasite that feed on human blood, and the number of reported infestations of these parasites has increased considerably during the last decade. Two 5th instar nymph-specific compounds, 4-oxo-hexenal and 4-oxo-octenal, were identified and synthesised. Utilizing domestic dogs (Canis lupus familiaris) in the identification of bed bug infestations has become popular during recent years. Their training is usually conducted using live bed bugs, however this thesis describes an alternative method of teaching dogs to find infestations. This alternative method is based on synthetic compounds and dogs trained in this manner have achieved a high positive indication rate. Two species of the tiny, Acacia leaf-eating insect pests in Australia known as thrips, Kladothrips nicolsoni and K. rugosus, have been investigated by means of larval extracts and have been shown to contain large amount of (Z)-3-dodecenoic acid which was synthesised and tested in bioassays. Fruit flies are common pests on fruit in almost every private household. Even though fruit flies has been investigated extensively, their chemical communication has not been completely elucidated. (Z)-4-undecenal was identified as a compound emitted by females, it was synthesised in high stereoisomeric purity and evaluated in biological assays. / FORE
7

Survey of different mealybug species and attending ants and their management in Virginia vineyards

Chalise, Pragya 01 November 2023 (has links)
Mealybugs (Order Hemiptera: Superfamily Coccoidea) represent a persistent problem in grape-growing regions globally, with a notable increase in infestations in recent times. The current study investigates the species composition and seasonal dynamics of mealybugs in vineyards. Pseudococcus maritimus and Ferissia gilli remain the dominant species, while Pseudococcus viburni was also spotted during two separate instances and Planococcus ficus remained absent. Commercially available pheromone delta traps and adhesive bands were deployed to capture the male mealybugs, while numerically higher efficacy was observed in the adhesive band trap. Notably, the placement of adhesive band traps on the cordon and trunk revealed differential male mealybug captures, probably indicating their movement within the vines. The research also divulges into the life cycle of mealybugs and their population densities during the sampling season. The main highlight has been the lower population density of earlier nymphal stages of the first generation of mealybugs followed by the colonization of grapevines by the second-generation crawlers. Adults of second generations give rise to the overwintering stages of mealybugs. Traditionally the research also explores the species and seasonal population dynamics of ants along with mealybugs and their management in Virginia vineyards. The activity of fifteen genera of ants in the vineyard was recorded, with some of the dominant ant genera like Tetramorium, Crematogaster, and Lasius were recorded in the vineyard actively tending and defending the mealybugs and moving them around. Fruit cluster infestation was also higher in the control treatment in comparison to sugar dispenser and ant bait dispenser treatments. This comprehensive assessment of ant diversity further deepens our understanding of the intricate ecosystem within vineyards. A spray trial using three different insecticides with distinct modes of action (Buprofezin, Bifenthrin, and Spirotetramat) in two of the commercial vineyards. Preliminary results indicate that on some days after treatment, insecticides effectively controlled mealybug populations, offering a glimmer of hope to vineyard owners grappling with infestations. Mealybugs pose a significant threat to grape cultivation, and this research provides valuable insights that can help vineyard owners and grape growers develop more targeted and effective control strategies. Species identification, understanding their behavior, and exploring potential allies in the fight against mealybugs are all crucial steps toward maintaining the health and productivity of vineyards in Virginia. While challenges remain in the battle against mealybugs, this research marks a significant step forward in safeguarding grape cultivation in Virginia and potentially reshaping strategies for controlling these persistent pests in vineyards. Growers and researchers alike eagerly await further developments and the practical application of these findings to protect the flourishing vineyards of the region. / Doctor of Philosophy / Mealybugs are common grapevine pests, recently causing a nuisance in vineyards across the United States and Canada. Some of the previously documented species of mealybugs common in the eastern part of the States include grape mealybug, obscure mealybug, Gill's mealybug, and long-tailed mealybugs. The research has mainly addressed the mealybugs and their tending ant species and their management in vineyards in Virginia. The study identifies grape mealybug and Gill's mealybug as the dominant species with occasional sightings of obscure mealybug and a lack of vine mealybug throughout the sampled vineyard sites. The male mealybugs were monitored using commercially available pheromone delta traps and adhesive band traps. Placement of adhesive band traps in the cordon and trunk of grapevines revealed different male mealybug capture data suggesting their movement within the grapevines. Two generations of mealybugs including the first generation with lower population density emerging out from the overwintering life-stage and the subsequent second generation responsible for colonizing different parts of the grapevines and producing overwintering life-stages were observed. Fifteen genera of ants were sampled from the vineyard via pitfall trap with some ants like pavement ants, acrobat ants, and medium garden ants actively tending and protecting the mealybugs. The use of sugar dispensers in the vineyards also led to lower fruit cluster infestations with mealybugs in comparison to the area without dispensers. The insecticidal spray trial using three different insecticides was also effective in controlling populations of mealybugs on some of the dates after treatment. The research offers valuable insights for grape growers, aiding in the development of effective control strategies for mealybug control. It emphasizes the importance of identifying the species present, understanding their behavior, and exploring potential allies and insecticide options in pest management.
8

Chiral building blocks for synthesis of pine sawfly sex pheromones Enantioselective Lipase Catalysed Acylations and Esterifications of Primary Alcohols and Acids and Synthesis of the Sex Pheromone of the Pine Sawfly Microdiprion pallipes

Nguyen, Ba-Vu January 2000 (has links)
This thesis describes the development of new methods for thepreparation of enantiomerically pure methyl branched alkylcompounds and their use as building blocks in the synthesis ofstereoisomerically pure pheromones of pine sawflies. The high regioselectivity, enantioselectivity and activityof lipases in organic solvent in conjunction withenvironmentally compatible reaction conditions have madelipase-catalysed synthesis an attractive alternative toconventional synthetic methods in organic chemistry. The lipasefromPseudomonas cepacia(PCL) was used in kineticresolutions of primary 2- methylalcohols by acylation of thealcohols with vinyl acetate/vinyl butyrate. For alcoholsstudied, PCL showed moderate enantioselectivity(E= 10-20) towards 3-alkyl- or 3- cycloalkylsubstitutedprimary 2-methylpropanols, whereas 3-aryl-2-methyl-1-propanolswere accepted with high E-values(E&gt;100). Esterification of substituted methylcarboxylic acids withprimary alcohols catalysed byCandida rugosalipase (CRL) was found to be anenantioselective reaction. In general, CRL showed highselectivity towards(S)-2-methylcarboxylic acids(E= 15-70) and also towards(R)-3-methylcarboxylic acids(E= 15-40). For substrates having a double bond located5-6 bonds from the carbonyl moiety a two-fold enhancement ofenantioselectivity value(E-value) was obtained compared to their saturatedanalogues,E≈ 15-25. Furthermore, the enantioselectivity of CRL towards a seriesof 3- to 8-methyldecanoic acids were studied. CRL surprisinglyshowed enantiorecognition for all of these acids within theE-value range of 2.3-68. Interestingly, whereas the lipaseshowed S-preference when the methyl group was situated ateven-numbered carbons, R-preference was observed for thesubstrates with the methyl group at odd-numbered carbons. In order to establish the stereoisomeric composition of thenatural sex pheromone of the pine sawflyMicrodiprion pallipes, all sixteen individual isomers of3,7,11-trimethyl-2-tridecanol (and their propionate esters)found in this species were synthesised in highdiastereoisomeric purities, 95.3-97.6%. The syntheses werebased on six enantiomerically pure building blocks, the fourstereoisomers of 1-lithio-2,6-dimethyloctane and the twoenantiomers ofcis-3,4- dimethyl-g-butyrolactone. <b>Keywords:</b>lipase,Pseudomonas cepacia,Candida rugosa, enantioselective, enantiomeric ratio,primary 2-methylalcohol, substituted-methylcarboxylic acid,pine sawfly,Microdiprion pallipes, sex pheromone,3,7,11-trimethyl-2-tridecanol, stereoisomer.
9

Chiral building blocks for synthesis of pine sawfly sex pheromones Enantioselective Lipase Catalysed Acylations and Esterifications of Primary Alcohols and Acids and Synthesis of the Sex Pheromone of the Pine Sawfly Microdiprion pallipes

Nguyen, Ba-Vu January 2000 (has links)
<p>This thesis describes the development of new methods for thepreparation of enantiomerically pure methyl branched alkylcompounds and their use as building blocks in the synthesis ofstereoisomerically pure pheromones of pine sawflies.</p><p>The high regioselectivity, enantioselectivity and activityof lipases in organic solvent in conjunction withenvironmentally compatible reaction conditions have madelipase-catalysed synthesis an attractive alternative toconventional synthetic methods in organic chemistry. The lipasefrom<i>Pseudomonas cepacia</i>(PCL) was used in kineticresolutions of primary 2- methylalcohols by acylation of thealcohols with vinyl acetate/vinyl butyrate. For alcoholsstudied, PCL showed moderate enantioselectivity<i>(E</i>= 10-20) towards 3-alkyl- or 3- cycloalkylsubstitutedprimary 2-methylpropanols, whereas 3-aryl-2-methyl-1-propanolswere accepted with high E-values<i>(E</i>>100).</p><p>Esterification of substituted methylcarboxylic acids withprimary alcohols catalysed by<i>Candida rugosa</i>lipase (CRL) was found to be anenantioselective reaction. In general, CRL showed highselectivity towards<i>(</i>S)-2-methylcarboxylic acids<i>(E</i>= 15-70) and also towards<i>(</i>R)-3-methylcarboxylic acids<i>(E</i>= 15-40). For substrates having a double bond located5-6 bonds from the carbonyl moiety a two-fold enhancement ofenantioselectivity value<i>(</i>E-value) was obtained compared to their saturatedanalogues,<i>E</i>≈ 15-25.</p><p>Furthermore, the enantioselectivity of CRL towards a seriesof 3- to 8-methyldecanoic acids were studied. CRL surprisinglyshowed enantiorecognition for all of these acids within theE-value range of 2.3-68. Interestingly, whereas the lipaseshowed S-preference when the methyl group was situated ateven-numbered carbons, R-preference was observed for thesubstrates with the methyl group at odd-numbered carbons.</p><p>In order to establish the stereoisomeric composition of thenatural sex pheromone of the pine sawfly<i>Microdiprion pallipe</i>s, all sixteen individual isomers of3,7,11-trimethyl-2-tridecanol (and their propionate esters)found in this species were synthesised in highdiastereoisomeric purities, 95.3-97.6%. The syntheses werebased on six enantiomerically pure building blocks, the fourstereoisomers of 1-lithio-2,6-dimethyloctane and the twoenantiomers of<i>ci</i>s-3,4- dimethyl-g-butyrolactone.</p><p><b>Keywords:</b>lipase,<i>Pseudomonas cepaci</i>a,<i>Candida rugos</i>a, enantioselective, enantiomeric ratio,primary 2-methylalcohol, substituted-methylcarboxylic acid,pine sawfly,<i>Microdiprion pallipe</i>s, sex pheromone,3,7,11-trimethyl-2-tridecanol, stereoisomer.</p>
10

CHEMICAL ECOLOGY OF BLUEBERRY SPANWORM, ITAME ARGILLACEARIA (PACKARD) (LEPIDOPTERA: GEOMETRIDAE)

De Silva, Amal E.C. 27 November 2012 (has links)
Blueberry spanworm, Itame argillacearia (Packard), is an important defoliator of wild (syn. ‘lowbush’) blueberry in north-eastern North America. Identification of I. argillacearia sex pheromone(s) could be useful for monitoring, mating disruption or mass trapping, as a way to improve integrated pest management programs for this pest. Thus, the main goal of this study was to identify sex pheromone(s) of I. argillacearia. The courtship, mating and oviposition patterns of I. argillaceara, was studied in the laboratory. GC/MS, GC/EAD and EAG analysis of pheromone gland extracts, in combination with y-tube experiments and two field trapping studies confirmed the chiral-alkenyl-epoxide, (3R,4S)-epoxy-(Z,Z)-6,9-17:H and tri-ene, (Z,Z,Z)-3,6,9-17:H as the major female-produced sex pheromone components. Contech Wing traps® placed at canopy level were effective for capturing male I. argillacearia moths.

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