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Dissertations / Theses on the topic 'Curculio'

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Published: 4 June 2021
Last updated: 10 March 2023

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1

Oberli, Frantz. "Influence de l'hôte végétal et de l'hétérogénéité spatiale et temporelle de l'environnement sur l'évolution des traits d'histoire de vie chez les insectes phytophages : exemple du balanin de la châtaigne, Curculio elephas Gyll. (coléoptère, Curculionidae)." Lyon 1, 2001. http://www.theses.fr/2001LYO10080.

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Notre travail s'intègre dans le cadre théorique de l'évolution des traits d'histoire de vie en environnement hétérogène à la fois dans l'espace et le temps. Il a pour but général de comprendre comment le type et la structure de l'habitat, ainsi que sa variabilité temporelle, influencent les comportements et les traits d'histoire de vie des insectes. L'objectif de notre étude est triple : 1) tester l'hypothèse des trade-offs (compromis évolutifs) générés par l'exploitation de différentes espèces végétales hôtes par les insectes oligophages, 2) tester l'influence de l'hôte végétal et de la structure d'habitat sur l'évolution des populations naturelles d'insectes en nous replaçant dans le cadre théorique des métapopulations et 3) comprendre comment la variabilité temporelle de l'habitat a pu sélectionner des stratégies mixtes de diapause (bet-hedging). Pour cela, nous avons choisi comme modèle biologique le balanin de la châtaigne qui se développe à la fois dans les châtaignes et les glands et peut vivre dans des habitats plus ou moins fragmentés. Nous avons montré que les forces sélectives liées à la plante hôte et à l'intervention de l'homme (via le ramassage des châtaignes) génèrent un trade-off entre la survie et la fécondité de l'insecte et que ce trade-off détermine en grande partie la fitness globale du balanin. Notre travail a également montré comment l'homme a influencé la structure et l'évolution des métapopulations de balanins dans différents types d'habitat. Enfin, l'ensemble de nos résultats démontre l'importance d'une variabilité de la durée de la diapause (bet-hedging) en réponse à la stochasticité environnementale dans l'évolution de Curculio elephas.
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2

Soula, Bertrand. "Evolution des caractères discrets en environnement variable : exemple de la durée du cycle de vie chez les insectes : application au balanin de la châtaigne Curculio elephas." Lyon 1, 2002. http://www.theses.fr/2002LYO10041.

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Notre travail s'inscrit dans le cadre théorique de l'évolution des traits d'histoire de vie en environnement variable. Son but est de préciser le déterminisme de la variabilité intra-populationnelle de la durée du cycle de vie incluant une diapause prolongée chez un insecte. Cette variabilité phénotypique peut théoriquement résulter, soit d'un polymorphisme génétique de stratégies pures, soit du bet-hedging diversifié (plasticité non-prédictive), c'est-à-dire une adaptation à la stochasticité environnementale (Seger & Brockmann, 1987). Nous avons démontré l'existence du bet-hedging diversifié chez le balanin de la châtaigne Curculio elephas. Pour cela, nous avons montré que la variabilité de la durée du cycle de vie ne pouvait pas être maintenue chez cette espèce par un polymorphisme génétique de stratégies pures. Nous avons en revanche montré que cette variabilité résultait d'une plasticité phénotypique non-prédictive en réponse aux conditions de nutrition pré-diapause des larves. Cependant, une variabilité génétique n'est pas absente d'un tel système, ce qui suggère l'existence d'un polymorphisme de différentes stratégies de bet-hedging. Par une approche éco-physiologique, nous avons précisé les mécanismes proximaux sous-jacents à la stratégie de bet-hedging. D'une part, nous avons mis en évidence un type de cycle long différent de celui supposé chez les espèces à diapause prolongée. D'autre part, nous avons montré que les individus à cycle long compensaient le coût métabolique dû à une vie plus longue avant la reproduction par des réserves lipidiques initialement plus élevées que chez les individus à cycle court. Enfin, nous avons proposé un mécanisme adaptatif permettant d'expliquer le cycle exprimé par les génotypes bet-hedgers.
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3

Hoffmann, Eric James. "Identification & characterization of key insecticide performance mechanisms for the control of plum curculio (Conotrachelus nenuphar) in Michigan tart cherries." Diss., Connect to online resource - MSU authorized users, 2008.

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4

Desouhant, Emmanuel. "Stratégies de ponte et traits d'histoire de vie chez les insectes : exemple du balanin de la châtaigne, Curculio elephas (coléoptère, curculionidae), en conditions naturelles." Lyon 1, 1997. http://www.theses.fr/1997LYO10338.

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Ce travail s'integre dans le cadre de l'evolution des traits d'histoire de vie chez les insectes. Il a pour but d'estimer les principaux parametres demographiques chez le balanin de la chataigne, curculio elephas, afin de predire quelle est la meilleure strategie de ponte en terme de compromis evolutif. Face un site de ponte, un insecte doit faire face a une sequence decisionnelle qui resume la strategie de ponte : 1) ou pondre ses ufs, 2) quand les pondre et 3) combien en pondre dans chaque site (charnov & skinner, 1985). Les strategies de ponte chez les insectes conditionnent la qualite des individus et le taux d'accroissement des populations. Nous avons montre a partir d'une etude du comportement de ponte qu'une femelle curculio elephas ne semble pas limitee par le temps pour realiser sa fecondite. En conditions naturelles, une femelle depose un ou deux ufs par chataigne dans 77% des fruits ; elle selectionne ses sites de ponte, evite ceux contenant du carpocapse, cydia splendana, mais pas ceux ayant deja recu une ponte de balanin. Nos resultats suggerent un comportement aleatoire de ponte mais uniquement sur une fraction des chataignes, l'autre partie etant evitee. Nous avons mis en evidence des correlations phenotypiques negatives entre la taille de ponte et d'une part, la survie larvaire et d'autre part la fecondite potentielle des femelles. D'un point de vue evolutif, nous avons montre, a partir des estimations des principaux traits d'histoire de vie, que la valeur selective d'une strategie (ou genotype) conduisant a la ponte d'ufs en paquets est inferieure a celle de la strategie actuellement observee, qui consiste a disperser les descendants dans de nombreux fruits. Dans la discussion nous nous interrogerons en particulier sur l'existence d'une taille optimale de ponte et sur l'influence d'un changement ancien de plante-hote sur la strategie actuelle de ponte chez le balanin.
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5

Cappiello, Luigia. "Un Commento al Curculio di Plauto (vv.1-370)." Doctoral thesis, Universita degli studi di Salerno, 2015. http://hdl.handle.net/10556/2129.

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2012 - 2013
This work is a partial commentary on Plautus’ Curculio. It comes from the lack of Curculio scientific commentaries and from the need of gathering and developing the starting points of the Plautine research. Unfortunately, the Plautine studies tradition is very ungenerous toward the Curculio. The scholars have usually dealt with the Curculio in generic works. They have sometimes studied specific features of this comedy. Before my commentary notes, there is an introduction where the whole play is examined. In my opinion, one can hardly deal with dating, model, set and so on without a look at all parts of the text. At the same time, the whole plot is considered in order to give possibility of impartial judgment on the comedy events. I have examined the first six scenes of the play (vv. 1-370). There is a short introduction to each one. The reference text is S. Lanciotti’s critical edition that was published by Quattroventi of Urbino in 2008. The few points where I don’t agree with professor Lanciotti are pointed out in the commentary notes. The history of Curculio text is discussed in the light of the choices of the most important Plautine publishers. Importance is attached with the Plautine use of the examined headwords in his whole corpus in order to notice possible trends. Puns and double meanings are discussed. Hints at the Historic, Legal and Customs substratum of the comedy age aren’t neglected. Words that allude to the stage arrangement and to the players’ movements are treated. [edited by author]
XII n.s.
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6

Manel, Stéphanie. "Modélisation de la durée de développement pré-imaginal chez les poïkilothermes sous régime de températures variables." Lyon 1, 1995. http://www.theses.fr/1995LYO10277.

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Nous proposons des methodes integrant les temperatures variables ainsi que la variabilite individuelle, permettant de predire la duree mediane de plusieurs stades de developpement d'insectes. Cette etude sera appliquee plus particulierement au balanin de la chataigne (curculio elephas). Une etude au laboratoire montre que les vitesses des developpements embryonnaire et larvaire du balanin sont lineaires en fonction de la temperature. Le logit de la proportion d'ufs ou de larves du balanin se developpant en conditions naturelles est modelise en fonction d'une echelle physiologique, lineaire. Deux methodes differentes d'estimation des parametres sont proposees: une indirecte (faisant appel a la methode de la vraisemblance profilee) et l'autre directe (estimant tous les parametres au maximum de vraisemblance). Elles conduisent a des resultats proches: par exemple le developpement embryonnaire necessiterait 109 dj, base 6,5c, soit huit jours a la temperature constante de 20c. Une distribution logistique est ajustee a la proportion des sorties larvaires observees a une date t par rapport au nombre total de larves sorties. Par exemple un uf eclos le 14 septembre donnera naissance a une larve qui quittera la chataigne le 24 octobre. Nous discutons egalement de la sensibilite des modeles a la temperature. Nous etudions la variabilite individuelle du developpement a partir des durees du premier et du dernier deciles des distributions. Des simulations ont montre que le nombre de dates d'observation de la population et la taille de l'echantillon, issu d'une population caracterisee par les frequences d'individus dans les divers stades de developpement, ont peu d'influence sur la precision des estimations des modeles. Nous avons egalement mis en evidence la difficulte a predire simultanement la duree des differents stades de developpement quand l'echelle physiologique n'est pas commune aux stades
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7

Hughes, Joseph. "Evolution and ecology of seed predation in weevils (genus Curculio)." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408848.

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8

Zhang, Xing. "Biogeography and biosystematics of plum curculio, Conotrachelus nenuphar (Herbst)/Wolbachia interactions." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/25948.

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This research focused on the reproductive incompatibility and genetic differences between the two strains of plum curculio, Conotrachelus nenuphar (Herbst). Two molecular markers served as the basis for the strain distribution analysis of plum curculio and Wolbachia symbiont. One marker is the partial mitochondrial cytochrome oxidase gene subunit I (mtCOI) of plum curculio. Another marker is the Wolbachia Surface Protein (wsp) gene of Wolbachia associated with plum curculio. First, the reproductive compatibility of cross-populations mating in plum curculio was studied during the summers of 2004 and 2006. The results confirmed the reproductive incompatibility among plum curculio geographic populations. A unidirectional incompatibility was revealed in an approximate north and south transect of the range of plum curculio (4 x 4 two factorial design: NY, VA, FL, and WV): there was a significant low fertility in WV males mated with NY (40%) and VA (29%) females. The Florida population showed a different pattern: FL males have a significantly lower fertility with VA (46%) and WV (37%) females while FL females were compatible with all males from the four populations. The results of experiment 2 indicated that within the northern geographic area populations (3 x 3 two factorial design: NY, MA, and NJ) were compatible with each other. An opposite unidirectional reproductive incompatibility was revealed in the combination of NJ males with FL females, which showed a significant low fertility (47%). A bi-directional incompatibility occurred between FL and WV reciprocal cross mating. FL males mated with WV females (26%) and WV males mated with FL females (21%) both have the significant low fertility compared to fertility of within their population matings. The genetic diversity among plum curculio populations from different geographic locations was investigated using the partial mtCOI gene. A total of 50 samples from 10 populations were sequenced. PCR products were 863 bp in length. A total of 23 unique sequence haplotypes were found in the 50 samples tested. Haplotype G (n = 5), L (n = 12) and T (n = 13) comprised 60% of 50 samples. The nucleotide distances between those haplotypes ranged from 0.12% to 4.87%. Genetic distances between northern and southern group plum curculios range from 4.17% to 4.87%. Two distinct major clades were found, using three different phylogenetic analyses: 1) neighbor joining (NJ), 2) maximum-parsimony (MP), and 3) maximum-likelihood (ML). 100% bootstraps support the northern clade and the southern clade was strongly supported (100/100/86, NJ/MP/ML) as well. The mid-southern subclade within the southern clade was also strongly supported (70/82/71, NJ/MP/ML) and the far-southern subclade was supported in NJ tree (81%) but was not resovled in MP and ML trees. The mid-southern subclade included haplotypes from two NJ, Washington, VA (Ra), Blacksburg, VA (BL) and 50% of WV populations and the far-southern subclade included haplotypes from FL, GA, Whitethorne, VA (Ke), Troutville, VA (Bo) and another 50% of WV populations. The results suggested that the northern and the southern clade could correspond with the northern and southern strains, respectively, of plum curculio. In this study, the mtCOI sequence was highly informative as a molecular marker in that it was useful to distinguish C. nenuphar from northern and from southern geographic locations in the eastern United States. However, the number of generations per year of several geographic populations within the southern clade still needs to be determined. The distribution of Wolbachia infection associated with plum curculio strains was investigated. 91 of 93 samples were infected by Wolbachia. Three unique Wolbachia strains were identified. The strains wCne1 and wCne2 (593 bp) were 97% identical, and their sequences were both 84% identical with wCne3 (590 bp). The wsp sequence of wCne1 was 99% identical to Wolbachia sequenced from the neotropical beetle, Chelymorpha alternans Boheman (Keller et al. 2004). The wCne2 sequence was 98.5% identical to the flower bug, Orius nagaii Yasunaga (Miura and Tagami, unpublished). The wCne3 sequence was 100% identical to Wolbachia sequenced from the tephritid fruit fly, Dacus destillatoria (Jamnongluk et al. 2000) and the ant, Formica exsecta (Reuter and Keller 2003). PCR - Restriction Fragment Length Polymorphism (RFLP) was used for superinfection detection. Of 93 samples, 15 (16.1%), 21 (22.6%), 19 (20.4%), 36 (38.7%) samples were infected by wCne1, wCne2, wCne1 plus wCne2, and wCne3, respectively. Only two (2.2%) samples had no infection. The wCne3 strain was always present as a single infection. Therefore, current results suggest that Wolbachia strains approximate the distribution of plum curculio strains: the northern strain is infected with wCne1 and wCne2 strains in supergroup B, the southern strain is infected with wCne3 strain in supergroup A and the mid-Atlantic region is the convergence area. Compared with the haplotype distribution of plum curculio mtCOI gene, there was a closer relation of the mid-southern PC clade to the far-southern clade than to the northern clade. However, Wolbachia symbionts in mid-southern PC are more closely related to those in northern PC than to those in far-southern PC. The relationship of Wolabchia infection with reproductive incompatibility between plum curculio populations is also discussed.
Ph. D.
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9

Racette, Gaétan. "Daily activity of plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), and implications for control." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63903.

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10

Price, Steven J. "Understanding the Biology of Clover Root Curculio and Improving Their Management Using Biofumigation in Alfalfa." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/6537.

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Clover root curculio (CRC) is a pest of alfalfa where larvae feed belowground damaging alfalfa roots. Regional knowledge of CRC activity and biology is limited making the development of pest management strategies difficult. One potential management technique for soil-dwelling pests is the use of biofumigant containing cover crops. Biofumigation can affect the survival and behavior of pest insects. However, biofumigant crops have not been evaluated against CRC or as a rotational crop compatible with alfalfa. The goals of this research were to determine 1) phenology, population sizes, and root damage severity of CRC occurring in the Intermountain region and 2) the direct and indirect suppressive effects of biofumigant cover crop incorporations on CRC and its agronomic compatibility in rotation with alfalfa. First, I observed that larval activity occurred from mid-spring to mid-summer and local larval densities were generally lower than those reported in the eastern U.S. Adult CRC began emerging from the soil in mid-summer having two population peaks. After the second fall peak of adults was when most eggs were deposited which continued through early winter. CRC damage to taproots was cumulative, increasing as stands age, with most damage occurring in the first few years of stand life and mostly occurring in the top 20 cm of roots. While the incorporation of biofumigant crops appeared to be compatible with alfalfa and did not negatively affect yield, in field trials, biofumigation did not suppress CRC, disrupt egg laying, or decrease feeding damage. In one greenhouse trial, biofumigants significantly suppressed adult feeding rates more than non-biofumigant plants but the effect was not consistent. Biofumigant incorporation timing, for field trials in particular, may have contributed to the lack of CRC suppression. Overall, my research provides a better understanding of CRC phenology and activity in northern Utah and will assist in improving the timing of management approaches in alfalfa.
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11

Riccardi, Cynthia L. "The effect of prescribed fire on fuel loads, seed germination, and acorn weevils (Coleoptera: Curculionidae) in mixed-oak forests of central Appalachia /." View abstract, 2005. http://wwwlib.umi.com/dissertations/fullcit/3191715.

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12

Pettini, Corinne. "Stratégies d'échantillonnage prenant en compte différents niveaux de structuration spatiale : application à deux insectes ravageurs de la châtaigne (Curculio elephas et Cydia splendana) et à une graminée, l'alfa (Stipa tenacissima)." Lyon 1, 1992. http://www.theses.fr/1992LYO10288.

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L'echantillonnage est une phase importante en ecologie et de la representativite des donnees depend fortement l'analyse et l'interpretation biologique. Dans cette etude, nous avons recherche un plan d'echantillonnage optimal pour deux modeles biologiques: les ravageurs de la chataigne, le balanin balaninus elephas et le carpocapse, cydia splendana, une graminee peuplant les hautes plaines steppiques d'afrique du nord, l'alfa stipa tenacissima. La demarche a consiste a definir les principales echelles de structuration spatiale au sein de la zone d'etude, de sorte a augmenter l'intensite d'echantillonnage aux niveaux de variabilite les plus forts et vice-versa. La description des structures a ete realisee par l'utilisation de tests statistiques non parametriques (indice de geary, indice de contagion vraie), par representation graphique des donnees et par l'analyse structurale du variogramme (theorie des variables regionalisees). Les differents niveaux d'heterogeneites mis en evidence sont integres dans le protocole d'echantillonnage par combinaison de plans elementaires (echantillonnage systematique, echantillonnage par degres, echantillonnage stratifie). La precision des differentes strategies a ete approchee a partir de simulations sur l'echantillon initial (technique du bootstrap)
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13

Mynhardt, Glene. "Population genetics of the pecan weevil, Curculio caryae Horn (Coleoptera: Curculionidae), inferred from mitochondrial nucleotide data." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4388.

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The pecan weevil, Curculio caryae Horn, is an obligate nut feeder of all North American hickory (Carya) and a key pest of the pecan, C. illinoinensis Koch. This study investigated population structure of the pecan weevil. Gene flow and genetic variation was estimated for 90 pecan weevil specimens sampled from the entire Carya range. Cladistic and nested clade analyses, as well as an analysis of molecular variance (AMOVA) of mitochondrial DNA cytochrome oxidase I (mtDNA COI) were performed. The data indicate C. caryae diverged from its sister species, C. nasicus approximately 4.3 million years before present (mybp). Six-hundred and forty equally parsimonious trees of 31 haplotypes demonstrated high genetic diversity across all pecan weevil samples, and significant regional subdivision. Three clades recovered in the parsimony and nested clade analyses were strongly associated with western, eastern and central localities sampled within C. caryae's range. The current distribution of C. caryae and population structure were explained by past glaciation events. Lineage divergence between the western and eastern populations occurred during the Pleistocene (approx. 1.1 million years ago), and a more recent divergence occurred between C. caryae populations east and west of the Appalachian mountain range (870,000 yrs. ago). Haplotypes were segregated by region, but further sampling is necessary to test for gene flow among these regions.
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14

Perrin, Hélène. "Biosystématique et écologie évolutive des Curculio (Coleoptera : Curculionidae) : Double radiation sur Ficus (Moraceae) et sur Fagales." Paris 7, 1991. http://www.theses.fr/1991PA066278.

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Le travail presente les resultats d'une etude menee en cote d'ivoire sur les curculionidae des ficus. Il met en evidence que le genre curculio (coleoptera, curculionidae), connu en milieu tempere sur fagales, est en milieu tropical (afrique-asie) infeode aux ficus. Cette double radiation amene une discussion sur l'evolution du genre curculio. A lamto, cote d'ivoire, deux especes de curculio coexistent sur deux especes de ficus (f. Sur et f. Vallis-choudae). Les individus de la plus grande espece, c. Congoanus, ont ete suivis par capture-marquage-lacher-recapture, ce qui a permis d'etudier la strategie d'exploitation de la ressource-figue par cette espece, et de comparer son comportement a celui de c. Lachaisei. Les males et les femelles de curculio congoanus different par la longueur du rostre, beaucoup plus long chez la femelle. Cette espece se prete a une recherche sur la selection sexuelle. Y-a-t-il un choix selectif d'un sexe par l'autre? l'analyse des caracteres (longueur du rostre, du thorax, de la suture elytrale) dans l'ensemble de la population (males et femelles) et chez les individus accouples a permis de tester cette hypothese. Il n'y a pas de selection sexuelle a l'interieur de cette espece
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15

Keesey, Ian W. "The seasonal occurrence, soil distribution and flight characteristics of Curculio sayi (Coleoptera: Curculionidae) in mid-Missouri." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5028.

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Thesis (M.S.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 11, 2008) Includes bibliographical references.
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16

Merville, Adrien. "Caractérisation de la symbiose bactérienne intracellulaire chez les charançons du genre Curculio et exploration de son rôle dans la coexistence d'espèces d'insectes en compétition." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10130.

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Parmi les théories explicatives de la biodiversité, la théorie des niches propose que des espèces en compétition puissent coexister durablement à la condition qu'elles expriment des différences de caractères phénotypiques conduisant à un partitionnement de leurs niches écologiques. Par ailleurs, l'acquisition de bactéries endosymbiotiques peut être assimilée à une extension du phénotype de l'hôte, susceptible de modifier sa niche écologique. Cependant, l'implication de ces micro-organismes endosymbiotiques dans la structure des communautés d'espèces d'insectes en compétition n'a encore jamais été envisagée. Mon hypothèse est que les communautés de bactéries endosymbiotiques hébergées par différentes espèces-hôtes en compétition pourraient impacter la dynamique des communautés d'hôtes en facilitant la différentiation de leurs traits et ainsi stabiliser leur coexistence. Réciproquement, les interactions de nature compétitive entre espèces-hôtes pourraient influencer la dynamique évolutive des cortèges endosymbiotiques de chacune de ces espèces en favorisant notamment les occasions de transfert horizontal de bactéries endosymbiotiques. Durant ma thèse, j'ai étudié les relations endosymbiotiques au sein des communautés composées de quatre espèces d'insectes phytophages spécialistes du chêne (Curculio spp., Coléoptères Curculionidés), qui sont en compétition pour les glands qui représentent le siège du développement larvaire. Afin d'envisager l'implication des endosymbiotes dans le partitionnement des niches écologiques de ces espèces, j'ai développé ma thèse autour de deux objectifs principaux visant à (i) décrire et comparer les cortèges de bactéries endosymbiotiques hébergés par les quatre espèces, par une caractérisation moléculaire des souches bactériennes et une mesure de leur prévalence dans les populations d'hôtes et (ii) identifier les cas de transferts horizontaux interspécifiques d'endosymbiotes à l'aide d'une approche multi-gènes couplée à l'estimation du taux de multi-infestation plurispécifique à l'échelle du gland. J'ai pu montrer que ces espèces d'insectes hébergent des cortèges endosymbiotiques distincts, trois des quatre espèces hébergeant leur propre endosymbiote secondaire majoritaire. Une telle différentiation pourrait contribuer au partitionnement de niches écologiques de ces quatre espèces, notamment au vu des différences, mises en évidence au cours de ma thèse, dans la période d'exploitation des glands au cours de la saison de reproduction. Par ailleurs, le fait que chaque espèce-hôte possède, en prévalence résiduelle, la plupart des symbiotes majoritaires chez d'autres espèces laisse suspecter des transferts horizontaux au sein de cette communauté. Cette hypothèse semble confirmée par la comparaison approfondie des souches de Wolbachia présentes dans ces communautés d'hôtes et par la proportion non négligeable de glands infestés simultanément par plusieurs espèces d'insectes. Les résultats obtenus au cours de ma thèse corroborent l'hypothèse d'un impact possible des communautés endosymbiotiques sur la dynamique des communautés d'hôtes en compétition et soulignent l'importance de prendre en compte l'échelle des communautés d'hôtes pour comprendre la dynamique des communautés bactériennes au sein des populations de l'espèce-hôte
Among biodiversity theories, the niche theory states that competing species can durably coexist whenever they exhibit differences in their traits leading to partitioning of their ecological niches. Moreover, housing symbiotic bacteria is now recognized as expanding the host phenotype and is thus likely to interfere with its ecological niche. Intriguingly, the question of whether endosymbionts are likely to shape communities of competing insect species has not yet been addressed in natural systems. My hypothesis is that endosymbiosis can be determinant in driving the dynamics of communities composed of competing host species by amplifying differences in theirs traits and thus, stabilizing their coexistence. Reciprocally, ecological interactions among these host species could have a decisive role in the evolutionary dynamic of endosymbiotic cortege of each species by providing opportunities of horizontal transfer of bacterial endosymbionts. During my PhD, I studied endosymbiotic relationships among communities consisting of four species of specialist oak weevil insects (Curculio spp., Coleoptera, Curculionidae) that are competing for egg-laying into acorns where the larva grow. The two main objectives of my thesis were (i) to describe and compare the endosymbiotic corteges housed by the four species, by means of molecular screening of the bacterial diversity in female ovaries and measuring their prevalence in males and females of host populations, and (ii) to check the existence horizontal transfers of endosymbionts between host species with a multigenic approach combined to estimating the probability for one acorn to be infested by larva belonging to distinct Curculio species. I found that the four weevil species overall harboured distinct endosymbiotic communities, and notably that three of the four species had their own major secondary symbiont. Additionally, I found that the four species had a clearly distinct period of larval development during the reproductive season. Such diversification of endosymbionts across species competing with each other might contribute to their temporal partitioning in the acorn use. Otherwise, the fact that each host species also hosts, with residual prevalence, most of endosymbionts found in the other species, argues for the existence of horizontal transfer among this community. This hypothesis seems to be confirmed by a fine-tuned comparison of the Wolbachia strains detected in these host communities and by the non negligible proportion of acorns which are simultaneously infested by two or more weevil species. These results support the hypothesis of an impact of endosymbiotic communities on the dynamics of competing host communities and point out the need to consider the host community scale in order to understand the dynamics of bacterial communities within host species populations
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17

Pelisson, Pierre-François. "Ressources pulsées et coexistence d’espèces en compétition : le cas d’insectes phytophages." Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10250.

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Les théories relatives à la biodiversité contrastent fortement quant au rôle qu’elles accordent aux différences de traits écologiques entre espèces (théorie des niches) ou à la stochasticité démographique (théorie neutre de la biodiversité) pour expliquer l’organisation des communautés d’espèces compétitrices. Les espèces en compétition pour une ressource pulsée permettent de tester à relativement court terme ces théories : dans le cadre de la théorie des niches, les espèces en compétition devraient présenter de fortes différences de traits les conduisant à exploiter différemment la ressource pulsée; elles devraient alors répondre démographiquement de manière différente aux fortes fluctuations en ressources et leurs dynamiques populationnelles devraient être asynchrones. Au contraire, dans le cadre de la théorie neutre, les espèces ne devraient pas présenter de différences majeures dans leurs caractères associés à l’exploitation de la ressource variable; elles devraient alors répondre de la même manière aux pulses et leurs dynamiques populationnelles devraient être synchronisées. Nos travaux, centrés sur quatre espèces du genre Curculio en compétition pour l’exploitation des glands de chêne, permettent de mettre en évidence (i) qu’un fort partitionnement global de leurs niches est assorti de dynamiques populationnelles asynchrones. (ii) Cependant, ils montrent également que deux des quatre espèces compétitrices apparaissent très similaires quant aux caractères étudiés et présentent des dynamiques de population synchronisées. Les résultats, dans leur ensemble, fournissent donc l’un des premiers arguments empiriques en faveur d'une théorie unifiée de la biodiversité
Understanding the organization of communities composed of competing species, and notably their biodiversity, has led to two theories that sharply contrast with each other about the role primarily assigned either to the differences in ecological traits among the species (niche theory) or to the demographic stochasticity (neutral theory of biodiversity). Species competing for a pulsed resource allow testing the two theories in short-term studies: the niche theory predicts that differences should exist in the traits of such species, which should allow them taking advantage of the resource in various ways; the species should thus respond differently to the fluctuations in the availability of the resource, resulting in asynchronous population dynamics. In contrast, the neutral theory predicts that the trait differences possibly existing between the species should not impact the way they use the variable resource; the species should then respond similarly to the pulses and their population dynamics should be synchronized. Our work, focusing on four phytophagous insect species (Curculio spp.) that compete for oak acorns (Quercus spp.), (i) show evidence of a clear, global niche partitioning combined with asynchronous population dynamics (ii) but points out that two of these species show similar ecological traits and display synchronized population dynamics. Overall, these results therefore provide one of the first empirical arguments in favor of a unified theory of biodiversity
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18

McClanan, Michelle Erin Garlic. "Biochemical Separation of Geographical Strains of Plum Curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), and Evaluation of Olfactory Attractants in Virginia Orchards." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/42434.

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Plum curculio, Conotrachelus nenuphar (Herbst), is an endemic pest of stone and pome crops of the eastern United States. Two morphologically identical strains of plum curculio have been described and documented in Virgina: a univoltine strain and a multivoltine strain. Because of the cryptic coloring and behaviours of the plum curculio adults, monitoring in orchards is difficult and often ineffective. RAPD-PCR assay was an effective method for separation of the geographical strains. Of the tested primers four, OPE 01, OPE 03, OPE 04, and OPE 07, gave 21 amplimers that are useful for distinguishing individuals from the univoltine and multivoltine populations. Gene targeted PCR revealed the presence of Wolbachia in both populations. Analysis of the wsp gene sequence showed the univoltine population of plum curculio is associated with a strain of Wolbachia in supergroup B, most closely related to a strain identified from Perithemis tenera (Say) (Odonata). The multivoltine populations of plum curculio are associated with strains of Wolbachia which are in supergroup A, and most closely related to Wolbachia strains associated with Dacus destillatoria, Bactrocera sp., and Callosobruchus chinensis Linn. Three different trap designs baited with grandisoic acid, plant volatiles, and a combination of pheromone and plant volatiles were tested. In 1999, significantly more plum curculios were captured with Tedders traps baited with grandisoic acid and unbaited control in traps baited with limonene, plum essence or ethyl isovalerate. In 2000, Circle traps baited with plum essence, sour cherry essence and grandisoic acid yielded no results. In 2001, branch mimic traps yielded no significant differences among three release rates of a blend of benzaldehyde, ethyl isovalerate, trans-2-hexenal, and limonene; although, there was a significant interaction between the pheromone and the host plant volatiles. Overall however, all three of the traps were not effective.
Master of Science
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19

Batalla, Carrera Laia. "Control biològic del diabló de l’avellaner Curculio nucum, L. (Coleoptera: Curculionidae), mitjançant nematodes entomopatògens (Rhabditida: Steinernematidae i Heterorhabditidae)." Doctoral thesis, Universitat Autònoma de Barcelona, 2013. http://hdl.handle.net/10803/120173.

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El diabló de l’avellana, Curculio nucum (L.) (Coleoptera: Curculionidae) és una plaga clau de l’avellaner, responsable de pèrdues important en la collita. Aquest treball pretén estudiar l’efectivitat dels nematodes entomopatògens per controlar C. nucum. Els nematodes entomopatògens pertanyen a les famílies Steinernematidae i Heterorhabditidae. Són paràsits d’insectes que porten associat un bacteri simbiòtic. D’un total de 295 mostres agafades en sòl d’avellaners al NE de la Península Ibérica, en 11 (3,73%) es van aïllar nematodes. Deu steinernemàtids i un heterorhabdítid van ser molecularment identificats com dos S. affine, cinc S. feltiae, dos S. intermedium, un Steinernema sp. i un H. bacteriophora. També es van aïllar fongs entomopatògens en 133 (45,08%) de les mostres, apareixent Metarhizium anisopliae (36,09%) i Beauveria bassiana (42,8%) com les espècies més freqüents. La virulència de vuit d’aquestes espècies de nematodes juntament amb una S. carpocapsae, aïllada en un jardí urbà de Barcelona, contra larves de C. nucum va ser avaluada. La mortalitat de larves deguda als nematodes varià del 10% causat per S. affine i el 78,75% per Steinernema sp. amb diferències significatives. La virulència del bacteri simbiont fou del 100% de mortalitat de larves a excepció de X. bovienii bacteri simbiont de S. affine (93,3%) i X. bovienii de S. feltiae (46,7%). La susceptibilitat de l’adult a quatre espècies de nematodes: S. feltiae, Steinernema sp., S. carpocapsae i H. bacteriophora també va ser avaluada. Els percentatges de mortalitat observats per Steinernema sp., S. feltiae i H. bacteriophora foren 1,7%, 16,7% i 8,3% respectivament, mentre que S. carpocapsae va demostrar ser el nematode més virulent, causant el 100% de mortalitat en l’adult. L’exposició d’adults a S. carpocapsae durant diferents períodes de temps va revelar que 15 minuts són suficients per matar 6,6-17% dels diablons i que el 100% de mortalitat es dóna a partir dels 120-240 minuts d’exposició. Per tal d’estudiar les diferències de susceptibilitat observades entre la larva i l’adult de C. nucum i les diferents espècies de nematodes entomopatògens utilitzats, s’avaluaren la penetració, les vies d’entrada i la resposta immunològica en la larva i l’adult de C. nucum. Els resultats indicaren que la larva és més susceptible a S. feltiae que a S. carpocapsae mentre que els adults foren molt susceptibles a S. carpocapsae. Es va determinar l’anus com a via preferent d’entrada en la larva i l’adult, tant per S. feltiae com per S. carpocapsae. La capacitat de penetració s’observà estar en relació amb la virulència del nematode. Basat en les nostres observacions la resposta immunològica queda descartada com a causa principal per explicar les diferències observades en la susceptibilitat als nematodes entomopatògens de larva i adult. La virulència de sis fongs entomopatògens contra la larva de C. nucum també fou testada. La major mortalitat de larves (80%) fou causada per M. anisopliae. Quan es van aplicar fongs i nematodes entomopatògens de manera combinada no s’observaren efectes antagònics o sinèrgics. Finalment, la persistència i la distribució vertical van ser avaluades en assajos de camp, mostrant que els nematodes foren capaços de persistir un mínim de 9 setmanes després de l’aplicació i que assoliren profunditats de fins a 40 cm. Els nematodes entomopatògens pogueren reduir de forma efectiva la població de C. nucum al camp. Un control eficaç requereix la combinació de diverses estratègies. Una aplicació d’estiu, utilitzant S. feltiae, Steinernema sp. o H. bacteriophora per controlar les larves quan s’enterrin al sòl, i una aplicació de primavera amb les mateixes espècies de nematodes per reduir la població d’insectes hivernants. Una aplicació addicional de primavera amb S. carpocapsae actuarà controlant de manera efectiva tant els adults hivernants com els que emergeixin del terra.
The Hazelnut weevil, Curculio nucum (L.) (Coleoptera: Curculionidae), is a key pest of hazelnuts causing an important economical impact on crop yield. This report summarizes the studies developed to prove the efficacy of entomopathogenic nematodes to control C. nucum. Entomopathogenic nematodes in the Steinernematidae and Heterorhabditidae families are insect lethal parasites with an endosymbiotic bacteria associated. From a total of 295 soil samples taken from hazelnut areas in the NE of the Iberian Peninsula, 11 (3.73%) were positive to entomopathogenic nematodes. Ten steinernematids and one heterorhabditid were molecular identified as two S. affine, five S. feltiae, two S. intermedium, one Steinernema sp. and one H. bacteriophora. Also, entomopathogenic fungi were recovered in 133 (45.08%) of the total samples, being Metarhizium anisopliae (36.09%) and Beauveria bassiana (42.8%) the most frequently isolated. The virulence of eight of these nematode species and strains, together with a S. carpocapsae isolated from an urban garden in Barcelona, was tested against larvae of C. nucum. Larval exposure to entomopathogenic nematodes resulted in mortality between 10% caused by S. affine and 78.75% by Steinernema sp. with significant differences. The virulence of the endosymbiotic bacteria was 100% mortality of larvae except for the X. bovienii belonging to S. affine (93.3%) and X. bovienii belonging to S. feltiae (46.7%). The susceptibility of the adult weevils to four nematodes species: S. feltiae, Steinernema sp., S. carpocapsae and one H. bacteriophora was tested. The mean mortality percentages caused by Steinernema sp., S. feltiae and H. bacteriophora were 1.7%, 16.7% and 8.3% respectively, while S. carpocapsae proved to be the most virulent nematode, causing 100% insect mortality. The adult exposure to S. carpocapsae over different periods of time revealed that 15 minutes were long enough to infect 6.6-17% of the weevils, and adult mortality reached 100% in 120 to 240 minutes of exposure. To assess the observed differences in susceptibility in relation to the insect stage of development and the nematode species used, penetration into the larva and adult of C. nucum, routes of entrance to the insect and insect immune response were evaluated. Results revealed larvae to be more susceptible to S. feltiae than to S. carpocapsae and adults were highly susceptible to S. carpocapsae. The anus was determined as the main entry route of S. carpocapsae and S. feltiae in adult insects and larvae. The penetration rate was found to be related to the nematode virulence. Our findings suggest rejecting the immune system as being responsible for the different susceptibility between larvae and adults. The virulence of six entomopathogenic fungi against larvae of C. nucum was also tested. The highest larvae mortality (reaching 80%) was due to M. anisopliae. When entomopathogenic fungi were applied in combination with entomopathogenic nematodes no antagonistic or synergistic effects were observed. Finally, short-term field persistence and the vertical distribution were assessed showing that nematodes can persist nine weeks after application and that nematodes can reach depths of 40 cm. The entomopathogenic nematodes can effectively reduce C. nucum populations in field. Efficient biocontrol requires a combined strategy. A summer application using S. feltiae, Steinernema sp. or H. bacteriophora to control the larvae when they are burying into the ground and a spring application with same nematodes species to reduce the overwintering larvae population. An additional spring application with S. carpocapsae would effectively control the overwintering and the emerging adults.
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20

Arias-LeClaire, Harold. "Pre-dispersal seed predation by weevils (Curculio spp.): The role of host-specificity, resource availability and environmental factors." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/665549.

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Pre-dispersal seed predation (PDSP, hereafter) significantly reduces plant reproductive output. The negative effects on plant fitness have triggered the development of different strategies to protect the seeds and/or reduce the impact of PDSP. These strategies, in turn, have promoted insect trophic specialization by means of morphological, physiological and behavioral adaptations. The close relationship between specialist insects and their host plants conditions insect community assemblage and population dynamics. Specialization would favour multi-species co-occurrence according to the Competitive Exclusion Principle, as different species cannot use the same limited resources. At the same time, specificity makes these species strongly dependent on a particular trophic resource, so that host plant population dynamics may lead to bottom-up forces influencing insect numbers. In this Thesis, I have studied the consequences of trophic specialization on species assemblage and demography in the most prevalent pre-dispersal predators of oak Quercus spp., chestnuts Castanea sativa and hazelnut Corylus avellana seeds, namely the weevils of the genus Curculio (Coleoptera: Curculionidae). Using DNA barcoding I could identify larvae infesting the seeds to the species level and hence assess resource partitioning among Curculio spp. in oak-hazelnut mixed forests. These forests were distributed along a latitudinal gradient in which the degree of overlap in the timing of seeding between the two species differed. The results showed that there was a strict host-based segregation, as the species found in hazelnuts was never recorded on oak acorns and vice versa. Contrary to other studies, segregation of seed parasites was not driven by seed size, as the seeds of both plants were large enough to host the larvae of any species. Rather, co-existence was more likely modulated by the combination of time partitioning, and probably by dissimilarities in dispersal-dormancy strategies among weevils. The timing of oogenesis differs among Curculio spp. and does the timing of seeding between oaks and hazelnuts. Early maturing hazelnuts are thus exploited only by Curculio nucum, as its eggs mature earlier too. Such specialization on a patchily distributed host plant conditioned its population genetics, as gene-flow between populations showed restrictions undetected in the other Curculio spp. that fed on the widespread oaks. Regarding the bottom-up effects of food availability on insect numbers we assessed that, as expected, irregular seed crops (masting) conditions weevil population dynamics and certainly help reducing acorn predation in Mediterranean oaks. However, we found that the effects of rainfall stochasticity on the success of weevil emergence from the soil (i.e. rain is needed to soften the soil) contributed to decrease seed predation in a similar magnitude to masting. The present Thesis stresses the need of introducing the time/phenology component (i. e. egg maturation, timing of seeding) to assess the mechanisms underlying host plant-specialist insect associations. Also, it shows that, despite their specificity, other environmental variables apart from food availability condition weevil numbers. This result must be considered in further studies on the significance of oak masting as a strategy to reduce pre-dispersal seed predation. Lastly, the results provide an insight into the potential consequences of Global Change on the communities of these specialist insects linked to oaks. The populations of a narrow specialist like the hazelnut feeding C. nucum will be very vulnerable to forest fragmentation, which will reduce more severely inter-population gene-flow and lead to population bottlenecks. In turn, climate change (e.g. temperature rising, rainfall decrease) could disrupt the matching phenologies of insects and their host plants and reduce insect population size.
La depredación de semillas predispersión (PDSP, de aquí en adelante) reduce significativamente el desempeño reproductivo de las plantas. Los efectos negativos han desencadenado el desarrollo de diferentes estrategias para proteger las semillas y/o reducir el impacto de PDSP. Estas estrategias, han promovido la especialización trófica de insectos a través de adaptaciones morfológicas, fisiológicas y de comportamiento. La estrecha relación entre los insectos especialistas y sus plantas hospedantes condiciona el ensamblaje de las comunidades de insectos y la dinámica poblacional. La especialización favorecería la coexistencia de múltiples especies de acuerdo con el Principio de Exclusión Competitiva, ya que estas no pueden usar los mismos recursos limitados. Al mismo tiempo, la especificidad hace que estas especies dependan fuertemente de un recurso trófico particular, de modo que la dinámica poblacional de plantas hospedadoras puede conllevar a que las fuerzas “bottom-up” influyan en el número de insectos. En esta Tesis, he estudiado las consecuencias de la especialización trófica en el ensamblaje de especies y la demografía en los depredadores pre-dispersión más prevalentes de Quercus spp., castañas Castanea sativa y avellanas Corylus avellana, principalmente los gorgojos del género Curculio (Coleoptera: Curculionidae). Usando técnicas de secuenciación de ADN pude identificar las larvas que parasitan las semillas a nivel de especie y, por lo tanto, evaluar la segregación de recursos entre especies de Curculio spp. en bosques mixtos de roble y avellana. Estos bosques se distribuyeron a lo largo de un gradiente latitudinal en el cual el grado de superposición de su distribución espacial difería entre las dos especies hospederas. Los resultados mostraron que hubo una estricta segregación basada en el hospedador, ya que la especie encontrada en avellanas nunca se registró en bellotas de roble y viceversa. Contrariamente a otros estudios, la segregación de los parásitos de las semillas no se debió al tamaño de la semilla, ya que las semillas de ambas plantas eran lo suficientemente grandes como para albergar las larvas de cualquier especie. Por el contrario, la coexistencia fue modulado con mayor probabilidad por la combinación de la partición de tiempo, y las diferencias en las estrategias de latencia y dispersión entre los gorgojos. El periodo de oogénesis de Curculio spp difiere con el periodo producción de semillas en robles y avellanas. Las avellanas de maduración temprana son explotadas solo por Curculio nucum, ya que sus huevos también maduran antes. Dicha especialización en una planta hospedera distribuida en forma dispersa condicionó su genética poblacional, ya que el flujo genético entre poblaciones mostró restricciones no detectadas en las otras especies de Curculio spp. que se alimentaban de los robles con distribución continua. Con respecto a los efectos “bottom-up” de la disponibilidad de alimentos sobre el número de insectos, evaluamos que, como era de esperar, la producción irregular de semillas (masting) condicionan la dinámica poblacional de los gorgojos y ciertamente contribuyen a reducir la depredación de las bellotas en los robles del Mediterráneo. Sin embargo, encontramos que los efectos de la estocasticidad de las lluvias sobre el éxito de la emergencia del gorgojo desde el suelo (la lluvia es necesaria para ablandar el suelo) contribuyeron a disminuir la depredación de semillas en una magnitud similar a la del masting. La presente Tesis enfatiza la necesidad de introducir el componente tiempo/fenología (es decir, la maduración del óvulo, el momento producción de semillas) para evaluar los mecanismos que subyacen a las asociaciones de insectos especialistas en plantas hospederas. Además, muestra que, a pesar de su especificidad, otras variables ambientales aparte de la disponibilidad de alimentos condicionan el número de gorgojos. Este resultado debe considerarse en estudios posteriores sobre la importancia de la producción irregular de semillas de roble como una estrategia para reducir la depredación de semillas pre-dispersión. Por último, los resultados proporcionan una idea de las posibles consecuencias del cambio global en las comunidades de estos insectos especializados vinculados a los robles. Las poblaciones de un especialista, como C. nucum que se alimenta de la avellana, será muy vulnerables a la fragmentación de los bosques, lo que reducirá el flujo genético entre las poblaciones y provocará cuellos de botella en la población. A su vez, el cambio climático (por ejemplo, aumento de la temperatura, disminución de las precipitaciones) podría alterar las coincidentes fenologías de los insectos y sus plantas hospederas y reducir el tamaño de la población de insectos.
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Pallen, Catherine. "Approche structurale et fonctionnelle en biologie de populations d'insectes : application à deux insectes de la châtaigne Laspeyresia splendana et Curculio elephas." Lyon 1, 1989. http://www.theses.fr/1989LYO10142.

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Le modele biologique choisi est celui de deux ravageurs de la chataigne: le carpocapse laspeyresia splendana et le balanin curculio elephas. Le site d'etude, environ 1 ha, est localise a st just chaleyssin (isere) pres de lyon et comprend plusieurs chataigniers isoles ou groupes. Les donnees analysees ont ete recueillies selon divers protocoles experimentaux dont l'echantillonnage systematique a maille carree. Elles s'etalent sur 4 annees d'etude, de 1982 a 1985. On demontre, en relation avec les caracteristiques de l'hote vegetal, l'existence de structures spatiales et spatio-temporelles tres marquees liees a l'infestation par les deux insectes. La repartition du balanin en est principalement a l'origine. Les structures temporelles se caracterisent par un fort echelonnement des emergences, et par suite celui du developpement larvaire. La maturite des chataigniers (precoce ou tardive) ne modifie pas la date moyenne des emergences, ni la vitesse du developpement larvaire. A l'echelle du fruit, la distribution gregaire des balanins peut etre interpretee en terme de strategies de ponte; par opposition, le carpocapse evolue plutot en solitaire. Les deux insectes montrent un comportement d'evitement au niveau de l'amande. Les resultats permettent de definir une population de balanins a l'echelle de l'arbre et de souligner l'existence d'echelles de structuration emboitees qui contribuent a determiner fortement les populations d'insectes
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Menu, Frédéric. "Diapause prolongée et variabilité des émergences chez les insectes : exemple du balanin de la châtaigne Curculio elephas Gyll. (coléoptère, Curculionidae)." Lyon 1, 1992. http://www.theses.fr/1992LYO10116.

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Malgre une litterature tres abondante sur la diapause celle qui se prolonge sur plusieurs annees a ete negligee. Notre objectif est d'etudier la dynamique des emergences du balanin de la chataigne curculio elephas et plus particulierement la diapause prolongee. Nos travaux ont notamment permis de preciser la periode et les mecanismes de levee de diapause chez le balanin. Les larves s'enterrent dans le sol entre octobre et novembre; la diapause est levee au cours du mois de decembre sans que les basses temperatures hivernales soient necessaires. Elle est suivie par une quiescence post-diapause qui se prolonge jusqu'en mars. Diapause et quiescence assurent la synchronisation du debut de la morphogenese dans la population. L'etalement des sorties de mi-aout a mi-septembre s'expliquerait essentiellement par des facteurs genetiques et par les conditions hydriques lors du developpement post-diapause et durant les emergences. En moyenne 40 a 50% des larves prolongent leur diapause sur plus d'une annee. Le choix de la duree de la diapause a lieu precocement: avant le mois de decembre; il dependrait notamment des conditions hydriques dans le sol en automne. Chez les insectes qui emergent apres un ou deux ans de vie souterraine, la fecondite et la longevite des femelles ne varient pas selon la duree de la diapause des larves. La variabilite pluriannuelle des emergences pourrait s'expliquer par une plasticite adaptative de type pile ou face (cooper et kaplan, 1982). Nos resultats empiriques et theoriques suggerent que la diapause prolongee est une reponse a l'imprevisibilite de plusieurs facteurs comme la secheresse estivale, la production en fruits et le ramassage des chataignes par l'homme. Une des consequences demographiques de la diapause prolongee est une relative stabilisation de l'effectif des populations de balanin. Ce resultat est a opposer a ceux obtenus par d'autres auteurs chez des especes dont la duree de la diapause est plus ou moins controlee par des facteurs predictifs (lies aux futures conditions de developpement et de reproduction). Nos travaux et plusieurs etudes recentes indiquent que la diapause prolongee n'est ni rare ni singuliere et que son interet evolutif ne peut plus etre sous-estime
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Rajon, Étienne. "Adaptation locale et optimalité des stratégies de dormance en environnement imprévisible : développements théoriques et validation expérimentale chez le balanin de la châtaigne, Curculio elephas." Lyon 1, 2008. http://www.theses.fr/2008LYO10322.

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Des variations temporelles imprévisibles de l'environnement, en modifiant les conditions de survie et/ou de reproduction des individus qui les subissent, affectent la capacité des gènes portés par ces individus à être transmis à long terme. Dans ce contexte, on s'attend à ce qu'une stratégie évolutive consistant à réduire l'effet de ces variations présente un avantage sélectif important. Les stratégies de dormance, qui consistent à ce qu'une partie d'une descendance retarde son développement par une dormance facultative ou additionnelle, peuvent par exemple évoluer dans ce contexte. En effet, les individus effectuant un développement plus long constituent une réserve de gènes, réduisant l'impact négatif de mauvaises conditions de survie et/ou de reproduction affectant les individus ayant effectué un développement "court". Ces stratégies de dormance sont retrouvées dans de nombreux taxa tels que les plantes, les insectes, et certains crustacés. Une première partie de cette thèse est consacrée à des développements théoriques concernant l'évolution des stratégies de dormance dans un environnement imprévisible. En effet, si on comprend bien l'évolution de ces stratégies dans une population isolée, peu de travaux se sont intéressés à leur évolution lorsqu'une structure spatiale existe. En particulier, l'évolution des stratégies de dormance dans deux populations échangeant des individus par la dispersion, et subissant des niveaux de variabilité environnementale différents, n'avait jamais été envisagée avant cette thèse. J'ai modélisé l'évolution des stratégies de dormance dans ce contexte, en envisageant une compétition locale générée par de la densité-dépendance. Dans un premier temps, j'ai considéré des conditions dans lesquelles le taux de dispersion spatiale entre populations était constant (i. E. Ce taux ne pouvait pas évoluer). En utilisant les outils de la dynamique adaptative, j'ai montré que des différences du niveau de variabilité environnementale entre les patches, ainsi qu'une faible dispersion spatiale, favorise une diversification adaptative des stratégies de dormance. Ainsi, dans un tel contexte, les stratégies de dormance observées dans chaque population devraient être adaptées aux niveaux de variabilité rencontrés. J'ai ensuite abandonné l'hypothèse d'un taux de dispersion spatiale fixe, et j'ai étudié la coévolution entre stratégies de dormance et stratégies de dispersion, dans le contexte décrit plus haut. Là encore, une diversification des stratégies de dormance intervient lorsque la différence de niveau de variabilité entre les patches est importante, et cette diversification s'accompagne d'une forte réduction du taux de dispersion spatiale. La seconde partie de cette thèse a consisté à tester l'hypothèse selon laquelle des différences importantes de fréquence de dormance prolongée observées entre deux populations naturelles du balanin de la châtaigne, Curculio elephas, peuvent être expliquées par des adaptations au milieu de vie. Les conditions nécessaires à une diversification des stratégies de dormance semblent rencontrées dans ces deux populations. Par une étude de données antérieure et de nouvelles expérimentations, j'ai montré qu'il existe (i) des différences de niveaux de variabilité environnementale dans ces populations et (ii) que la fécondité dans ces populations est régulée localement par la densité. Afin de déterminer si les différences observées entre les deux populations ont une origine adaptative, j'ai mené des expériences de transfert entre localités. Ensuite, j'ai testé l'hypothèse selon laquelle les stratégies observées dans ces populations correspondent bien au résultat attendu après l'action de la sélection naturelle, en confrontant les stratégies de dormance observées aux prédictions d'un modèle réaliste tenant compte de notre connaissance de ces populations. Les résultats obtenus suggèrent qu’une partie des différences observées entre les deux populations est adaptative
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Guidone, Loredana <1978&gt. "Indagini sull'artropodofauna del nocciolo con particolare riguardo a eterotteri coreidi e pentatomidi e Curculio nucum Linnaeus, responsabili di decrementi quali-quantitativi delle produzioni corilicole." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/185/1/TesiGuidone.pdf.

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Guidone, Loredana <1978&gt. "Indagini sull'artropodofauna del nocciolo con particolare riguardo a eterotteri coreidi e pentatomidi e Curculio nucum Linnaeus, responsabili di decrementi quali-quantitativi delle produzioni corilicole." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/185/.

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Ooko, Edna [Verfasser]. "Molecular mechanism of action and pharmacogenomics of curcumin, curcumin synthetic derivatives and combinations with curcumin in cancer therapy / Edna Ooko." Mainz : Universitätsbibliothek Mainz, 2017. http://d-nb.info/1128922738/34.

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Zetterström, Susanna. "Isolation and synthesis of curcumin." Thesis, Linköpings universitet, Organisk Kemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-84509.

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The aim of this thesis was to evaluate pre-existing methods for isolation and synthesis of curcumin. Two different isolation methods were used, where only the extraction step differs from each other. To obtain pure curcumin, column chromatography was needed to separate the compound from its analogues. As for the isolation the synthesis was also carried out by two different methods, the first in a conventional way and the second one by using irradiation of microwaves. The result of the experiments shows that by comparing the effectiveness and expense of the methods, the synthesis would probably be the easiest way of obtaining pure compound. Because of the more straightforward method, without cumbersome separation steps from the curcumin analogues, the synthesis was a faster way of obtaining the compound and gave more pure curcumin than the isolation procedures from turmeric.
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Henriques, Magda Alexandra Carvalho. "Curcumin and a new Rutheno(II)curcumin Complex : caracterização e avaliação das suas potencialidades biológicas." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/21219.

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Mestrado em Bioquímica - Métodos Biomoleculares
A curcumina é um pigmento de cor amarela, da família dos polifenóis, obtido a partir dos rizomas da planta Curcuma longa. É dotada de diversas propriedades biológicas que se relacionam com a vasta gama de alvos moleculares que possui, sendo de destacar a sua atividade anticancerígena já provada em diversas linhas celulares cancerígenas. No entanto, a atividade biológica da curcumina é limitada pela sua baixa biodisponibilidade que se deve principalmente à sua fraca solubilidade e rápida degradação em condições fisiológicas. Uma estratégia para contornar as limitações terapêuticas da curcumina é a sua complexação com iões metálicos, nomeadamente com complexos de ruténio(II). Neste trabalho foi preparado um novo complexo de curcumina com ruténio(II) e tritiaciclononano [9anoS3] com o objetivo de aumentar a solubilidade da curcumina em meio fisiológico. A curcumina foi extraída e purificada a partir de rizomas secos e pulverizados de Curcuma longa sendo depois desprotonada e coordenada com o precursor [Ru(II)(9anoS3)(DMSO)Cl2] (DMSO=dimetilsulfóxido). A estrutura e pureza do complexo formado, [Ru(II)(9aneS3)(curcumina)(S-DMSO)]Cl foi avaliada por Ressonância Magnética Nuclear de 1H e 13C, espectrometria de massa e análise elementar. A afinidade do novo complexo para ligação ao ácido desoxirribonucleico (ADN) foi estudada por ensaios de titulação e por determinação da variação na temperatura de desnaturação do ADN de esperma de salmão. Este estudo permitiu determinar que o complexo tem a capacidade de intercalar com o ADN com uma constante de ligação comparável aos intercaladores de ADN já conhecidos (4.00x105 M-1). A atividade citotóxica deste complexo contra o cancro de próstata foi estudada in vitro, usando como controlo positivo a curcumina. Mais ainda, aproveitando o potencial fotossensibilizador da curcumina, os ensaios foram feitos na presença e na ausência de luz. Para isso, usaram-se culturas celulares humanas isoladas de carcinoma de próstata (PC-3) e a toxicidade foi avaliada em linhas celulares prostáticas não tumorais (PNT-2). Com estes ensaios verificou-se que o complexo preparado não tem efeito citotóxico nem fototóxico nas concentrações usadas para as linhas celulares estudas. Mais, observou-se que a curcumina apresenta, no escuro, efeito citotóxico nas concentrações usadas e ainda, que este efeito é fortemente potenciado na presença de luz, sendo um potencial agente para terapia fotodinâmica em cancro de próstata.
Curcumin is a yellow pigment, of the family of polyphenols, obtained from the rhizomes of the Curcuma longa. It is provided with several biological properties which relate with the wide range of molecular targets that possesses, especially the anticancer activity already proven in various cell lines. However, the biological activity of curcumin is limited by their low bioavailability which is mainly because their poor solubility and rapid degradation in physiological conditions. One promising strategy to circumvent the therapeutic limitations of curcumin is the binding with metal ions, namely with ruthenium(II) complexes. In this work, was prepared a new complex of curcumin with ruthenium(II) and trithiacyclononane (9aneS3) with the aim of increasing the solubility of curcumin in physiological medium. The curcumina was extracted and purified from the powder rhizomes of Curcuma longa being after deprotonated and coordinated with the precursor [Ru(II)(9aneS3)(DMSO)Cl2] (DMSO=dimethylsulfoxide). The structure and purity of the prepared complex, [Ru(II)(9aneS3)(curcumina)(S-DMSO)]Cl was evaluated by 1H and 13C Nuclear Magnetic Resonance spectroscopies, mass spectrometry and elemental analysis. The affinity of the new complex to bind to deoxyribonucleic acid (DNA) was studied by titration assays and determination of the variation on sperm salmon DNA melting temperature. This study allowed to determine that the complex has ability to intercalate with DNA with a binding constant comparable with classical intercalators. The cytotoxic activity of this complex against prostate cancer was studied in vitro, using curcumin as a positive control. Moreover, taking advantage of the photosensitizer potential of curcumin, the assays were made under dark and light conditions. For this, human cell cultures were used isolated from prostate carcinoma (PC-3) and the toxicity was evaluated in non-tumour prostate cells (PNT-2). With these tests, it was found that the new complex do not have any cytotoxic or phototoxic effect in the same concentrations range tested for cell lines studied. Further, was observed that the curcumin presents, in dark, cytotoxic effect and, that this effect is strongly potentiated by light presence, with a potential for photodynamic therapy in prostate cancer.
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29

Bilmen, Jonathan Gavin. "The effects of pharmacological agents on intracellular Ca2+ pumps and channels." Thesis, University of Birmingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252549.

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Liu, Qing. "Curcumin induces cell inhibition in breast cancer cells." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38688608.

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Makhoul, Georges. "Nano-encapsulated curcumin in a chinchilla ear model." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95197.

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Cisplatin is an extensively used chemotherapeutic agent in the treatment of a broad spectrum of tumors. Ototoxicity is currently the most frequent dose limiting side-effect of cisplatinum chemotherapy. Ototoxicity has been shown to be the result of two mechanisms: oxidation, and more recently: inflammation. Various agents have been studied to prevent cisplatin ototoxicity. None has been proven effective in clinical trials to this date. Curcumin, a spice derived from a plant called Curcuma longa, possesses antioxidant activity and inhibits mediators of inflammation. However, curcumin low solubility in water and its low bioavailability limit its use. These issues can be solved using a novel technique called nano-encapsulation. In this research project, we wanted to find out whether curcumin could be nano-encapsulated, and, if so, whether the nano-encapsulated curcumin applied transtympanically is ototoxic, and whether it could be detected in the cochlear fluid and the blood. To answer these questions, a polymer of N-isopropylacrylamide (NIPAM), N-vinyl-2-pyrrolidone (VP), Poly(ethyleneglycol) monoacrylate (PEG-A) was formed. Curcumin was then mounted in this polymer. Different measurements were performed to characterize the created molecule such as the fourier transform infrared (FTIR) spectroscopy, the ultraviolet visible (UV-Vis) spectroscopy, and the atomic force microscopy (AFM). Results showed that curcumin was indeed nano-encapsulated. To test the safety of the nano-encapsulated curcumin, it was applied transtympanically to the ears of 5 chinchillas. The hearing was recorded using the auditory brainstem response (ABR) and the distortion product otoacoustic emission (DPOAE). Results of this pilot study showed that the nano-encapsulated curcumin is not ototoxic. To detect the presence of the nano-encapsulated curcumin in the cochlear fluid and the blood, it was applied transtympanically to chinchillas. The cochlear fluids and the blood samples were withdrawn
La cisplatine est un agent chimiothérapeutique largement utilisé dans le traitement d'un vaste éventail de tumeurs. L'ototoxicité est actuellement l'effet secondaire le plus important limitant l'utilisation de la cisplatine. L'ototoxicité résulte de deux mécanismes connus soit : l'oxidation, et plus récemment: l'inflammation. Plusieurs agents ont été étudiés pour éviter l'ototoxicité de la cisplatine. Jusqu'à ce jour, aucun n'a été prouvé efficace en clinique. La curcumine, une épice tirée d'une plante appelée Curcuma longa, possède une activité anti-oxidante et inhibe les médiateurs de l'inflammation. Toutefois, la faible solubilité de la curcumine dans l'eau et sa faible biodisponibilité limite son utilisation. Ces deux problèmes peuvent être résolus en utilisant une nouvelle technique appelée la nano-encapsulation. Dans ce projet de recherche, nous voulions déterminer si la curcumine pourrait être nano-encapsulée, et, si oui, si la curcumine nano-encapsulée appliquée à travers le tympan serait ototoxique, et si elle pourrait être décelée dans le liquide cochléaire et le sang. Pour répondre à ces questions, un polymère de N-isopropylacrylamide (NIPAM), N-vinyl-2-pyrrolidone (VP), et de poly (éthylène glycol) monoacrylate (PEG-A) a été formé. La curcumine a été ensuite incorporée dans ce polymère. Différentes mesures ont été réalisées pour caractériser la molécule créée comme la spectroscopie infrarouge à transformée de fourier (IRTF), la spectroscopie ultraviolet visible (UV-Vis) et la microscopie à force atomique (AFM). Les résultats ont montré que la curcumine a été effectivement nano-encapsulée. Pour tester la sécurité de la curcumine nano-encapsulée, une application transtympanique a été délivrée aux oreilles moyennes de 5 chinchillas. L'audition a été mesurée en utilisant la réponse auditive du tronc cérébral (RAT) et les émissions oto-acoustiques évoquées par produit$
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32

Liu, Qing, and 劉晴. "Curcumin induces cell inhibition in breast cancer cells." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38688608.

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33

Salehi, Dermanaki Pezhman. "Prevention of cisplatin ototoxicity by curcumin loaded nanoparticles." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121427.

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Cisplatin is an effective chemotherapeutic agent which causes oxidative and inflammatory damages to the cochlea, the hearing organ of the auditory system. The degenerative changes of the cochlea as a result of cisplatin chemotherapy lead to permanent hearing loss in patients, especially in younger children. Curcumin is a phytochemical compound known to exert various biological properties including acting as an effective antioxidant agent. In this study, curcumin was encapsulated by NIPAAM/VP/PEG-A nanoparticles to increase the bioavailability of the drug. Our hypothesis is that a combination therapy of curcumin loaded nanoparticles and dexamethasone can reduce the cisplatin-induced oxidative and inflammatory stress to the hearing organ. In a first step, characterization of the curcumin nanoparticles showed moderate stability in aqueous matrix, and temperature related slight release pattern of the curcumin from the nanoparticles. In the next phase, the protective effect of curcumin nanoparticles and dexamethasone against cisplatin damage were tested on auditory cells and in a guinea pig model. The in vivo experiments included the auditory brainstem response, antioxidant enzyme assays and morphological assessment of the cochlea. The results of our experiments showed that a combination treatment of curcumin loaded nanoparticles and dexamethasone reduced cisplatin-induced degenerative changes both in vitro and in vivo.
Le cisplatin est un agent chimiothérapeutique efficace qui cause des effets néfastes oxydatifs et inflammatoires à la cochlée, l'organe jouant un rôle primordial dans l'audition. Les changements dégénératifs de la cochlée suite au traitement avec le cisplatin entrainent une perte auditive permanente chez les patients, particulièrement chez les jeunes enfants. Le curcumin est un composant phytochimique qui peut exercer diverses propriétés biologiques, particulièrement comme agent antioxydant efficace. Dans cette étude, le curcumin a été encapsulé par des nanoparticules NIPAAM/VP/PEG-A afin d'augmenter la biodisponibilité du médicament. Notre hypothèse est qu'un traitement avec du curcumin encapsulé en nanoparticules en combinaison avec la dexaméthasone peut réduire le stress oxydatif et l'inflammation induite par le cisplatin à l'organe auditif. Dans une première étape, la caractérisation des nanoparticules de curcumine a montré une stabilité dans la matrice aqueuse, ainsi qu'une légère libération du curcumin des nanoparticules. Dans la phase suivante, l'effet protecteur des nanoparticules de curcumin combiné avec de la dexaméthasone contre les effets néfastes du cisplatin ont été testés sur des cellules auditives et un modèle de cochon d'inde. Les expériences in vivo comprenaient des réponses auditives cérébrales, des tests d'enzymes anti-oxydantes et des évaluations morphologiques de la cochlée. Les résultats in vitro et in vivo ont affirmé qu'un traitement de curcumin encapsulé en nanoparticules en combinaison avec la dexaméthasone réduit les changements dégénératifs induits par le cisplatin.
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Yan, Dejun. "THE EFFECT OF CURCUMIN ON LEWIS LUNG CARCINOMA." Bowling Green State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1308588440.

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Li, Huamin. "Synthesis of Curcumin-based Ligands for Molecular Knots." Ohio University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1219086414.

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36

Daniel, Sheril. "An investigation into the neuroprotective properties of curcumin." Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1003231.

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An increasing number of studies show that nutritional antioxidants such as vitamin E and polyphenols are capable of blocking neuronal death in vitro and may have therapeutic properties in animal models of neurodegenerative diseases including Alzheimer’s and Parkinson’s diseases. In the present study, the neuroprotective ability of one such polyphenolic antioxidant, curcumin, was investigated. Curcumin is the yellow curry spice derived from turmeric, and is widely used as a dietary component and herbal medicine in India. Most neurological disorders are postulated to have an oxidative or excitototoxic basis. Thus the effects of curcumin on oxidative stress in the rat brain were investigated. Curcumin, administered to the rat in vivo and in vitro, was able to exert protective effects on oxidative damage in the brain, induced by cyanide, a mitochondrial inhibitor. Curcumin also offered protection against quinolinic acid induced lipid peroxidation, and this protection was extended to lipid peroxidation induced by metals such as lead and cadmium in the rat brain. Experiments conducted on the pineal gland revealed an increased production of the neuroprotective hormone melatonin in presence of curcumin in vivo. The hippocampus is functionally related to vital behaviour and intellectual activities and is known to be a primary target for neuronal degeneration in the brains of patients with Alzheimer’s disease. Histological studies were undertaken to assess the effects of curcumin on lead induced toxicity on the rat hippocampus, the results of which show that curcumin affords significant protection to the hippocampus of the lead treated rats. This study also sought to elucidate possible mechanisms by which curcumin exerts its neuroprotective capabilities. Curcumin was found to inhibit the action of cyanide on the mitochondrial electron transport chain, one of the most common sources of free radicals. Electrochemical, UV/VIS and Infrared spectroscopy were used to characterise interactions between curcumin and the metals lead, cadmium, iron (II) and iron (III). Curcumin was shown to directly chelate these metals with the formation and isolation of two new curcumin complexes with lead, and one complex each with cadmium and iron (III). These results suggest chelation of toxic metals as a mechanism of neuroprotection afforded by curcumin. The need for neuroprotective agents is urgent considering the rapid rise in the elderly population and the proportionate increase in neurological disorders. The findings of this study indicate that curcumin, a well-established dietary antioxidant, is capable of playing a bigger role in neuroprotection, which needs to be further explored and exploited.
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Fujiwara, Hideya. "Curcumin inhibits glucose production in isolated mice hepatocytes." Kyoto University, 2008. http://hdl.handle.net/2433/124224.

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Lence, Nicole Louise. "IMPACT OF GINGER-RELATED COMPOUNDS, ZINGERONE AND CURCUMIN, ON PPARγ ACTIVATION, LIPID ACCUMULATION, AND CELL VIABILITY IN 3T3-L1 FIBROBLASTS." OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1227.

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The prevalence over overweight and obesity has risen dramatically during the past few decades corresponding with a clustering of metabolic pathologies including cardiovascular disease, type 2 diabetes, endometrial, breast, and colon cancers. Obesity is not only implicated as one of the primary causes of these degenerative diseases but also represents a major component of the metabolic syndrome. In obesity, the primary defect leading to these metabolic pathologies appears to be an impairment of adipogenesis resulting in adipocyte hypertrophy and dysfunction. Current pharmacological therapies prescribed for T2DM, such as thiazolidinones (TZDs), improve insulin sensitivity through regulation of adipogenesis. However, utilization of these drugs is often associated with several side effects, including weight gain, liver disease, and bone loss. Thus, there is an important need to identify alternative therapies that can modify these adipogenic regulators without adverse complications. Ginger (Zingiber officinale Roscoe), a member of the Zingiberaceae family, has a long history of use in traditional medicine and as been used for a wide array of ailments such as arthritis, diabetes, nausea, and stroke. Several studies have demonstrated anti-emetic, anti-inflammatory, and anti-carcinogenic properties of ginger. When used at high concentrations (μM), two phytochemcials derived from ginger root curcumin and zingerone, have been shown to promote weight loss and modify adipogenic signaling. However, due to the low bioavailability of curcumin the physiological relevance of these findings remains to be determined. The purpose of this study was to determine the extent to which curcumin and zingerone modify adipogenesis in 3T3-L1 fibroblasts. To determine the effects of the bioactive components in varying concentrations, 3T3-L1 preadipocytes were exposed to either 100pM, 100nM, or 100μM of curcumin or zingerone and tested for cell viability, lipid accumulation, and PPARγ activation. The results of this study suggest that high concentrations of curcumin (100 μM) may be toxic to 3T3-L1 fibroblasts in vitro and significantly inhibit both cell viability and lipid accumulation. The resultant low PPARγ activity may be attributable to cell necrosis rather than dose-dependent inhibition, suggesting need for further research into extreme curcumin supplementation. While results for zingerone did not differ significantly from vehicle, the results of this study provide evidence that further research is needed to ascertain to what extent curcumin and zingerone dose-dependently modify PPARγ and TCF/LEF in 3T3-L1 fibroblasts using lower physiologically relevant doses.
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39

Kwon, Youngjoo. "Effect of aging on colonic chemoprevention by dietary curcumin." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3543.

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Thesis (Ph. D.) -- University of Maryland, College Park, 2006.
Thesis research directed by: Food Science. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Schmitt, Bonell. "Curcumin analogues as ligands for Re (I) and (V)." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1020975.

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Coordination properties of 4-bromo-N-(diethylcarbamothioyl)benzamide (Hbeb) and 4-bromo-N-(diphenylcarbamothioyl)benzamide (Hbpb) with oxorhenium(V) and rhenium(I) are reported and discussed. Transition metal complexes of these ligands were studied due to the wide range of applications of thiourea derivatives in biological fields. N-[Di(alkyl/aryl)carbamothioyl]benzamide derivatives readily coordinate to metal ions as O,S-donors and the catalytic property of the complexes can be altered by these ligands, due to steric and electronic properties provided by various substituents. The coordination possibilities of curcumin with rhenium(V) are discussed, as well as the difficulties encountered. Analogues of curcumin have been made, which also contains a seven-spacer unit between the phenyl rings, which would be more reactive and more effective in bonding to rhenium and which have greater or a similar biological activity to curcumin. This was done by assessing the coordination properties of 1,5-bis(salicylidene)thiocarbohydrazide (H4salt) and 2,4-bis(vanilidene)thiocarbohydrazide (H4vant) with oxorhenium(V) and rhenium(I) starting materials. Two rhenium(V) complex salts of the core [ReX(PPh3)2]4+ (X = Br, I), containing a coordinated imido nitrogen, are reported. One is a ‘2+1’ complex, coordinating bi- and monodentately, with the other a similar ‘3+0’ complex containing a tridentate imido-coordinated Schiff base. Selected compounds were tested against oesophageal cancer cell lines in order to evaluate and compare their effectiveness in eliminating or reducing the cancer cells in the test medium during biological testing.
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41

Thiel, Stefanie [Verfasser]. "Farbverhalten von Curcumin in sauren wässrigen Systemen / Stefanie Thiel." Aachen : Shaker, 2004. http://d-nb.info/1170530184/34.

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42

Saathoff, John. "Curcumin/Melatonin Hybrids as Neuroprotective Agents for Alzheimer's disease." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4586.

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Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the leading cause of dementia, affecting ~5.2 million Americans. Current FDA approved medications provide mainly symptomatic relief and there are no agents available to delay or cure this disease. Multiple factors such as amyloid-β aggregates, dyshomeostasis of biometals, oxidative stress, and neuroinflammation have been implicated in the development of AD. Even though significant advances have been made in understanding the mechanisms leading to AD, the exact etiology still remains elusive. Given AD’s multifactorial nature, a multifunctional strategy of small molecule design would help to identify novel chemical templates. Recently our lab has developed hybrid molecules of curcumin and melatonin that exhibited potent neuroprotective ability in various AD models. Further modifications identified a lead compound with potent neuroprotective and antioxidative activity in MC65 cells, while also establishing the hybrid strategy as a viable approach in providing unique chemotypes with novel pharmacology. Further preliminary biological studies suggest that the lead is orally available and exhibits multifunctional properties both in vitro and in vivo on AD pathologies, thus strongly encouraging further structural examination. Herein, we report the structural exploration of this chemical template through structure-activity relationship studies at three domains: the phenyl domain, α,β-unsaturated β-ketone amide domain, and the indole domain. Collectively, the results show that the chemical space around the curcumin portion doesn’t favor electronic or steric/hydrophobic interactions, but might favor pi-pi (π-π) and hydrogen-bond interactions. Additionally, the α,β-unsaturated β-ketone amide domain is not as important as the linearity of the β-ketone acetamide. Moreover, the results indicate that a free rotatable β-OH might be the actual moiety that is important for the observed biological activity through favorable hydrogen bonds. Finally, steric interactions are not favored in the chemical space surrounding the indole nitrogen, suggesting that hydrogen bond interactions are required for the observed neuroprotective activity. Conversely, a hydrogen bond acceptor is necessary at the 5-position of the indole ring and bulky substitutions can be accommodated, with restrictions, suggesting steric tolerance and hydrophobic interactions at this position. These modifications have yielded a series of novel compounds that are capable of modifying AD pathology while shedding further light onto the chemical scaffold thus warranting future investigations into the development, optimization, and characterization of these curcumin/melatonin hybrids as potential treatments for AD.
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43

James, Mark Ian. "Treatment of metastatic colorectal cancer : a role for curcumin?" Thesis, University of Leicester, 2015. http://hdl.handle.net/2381/32351.

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Colorectal cancer remains the third largest cause of mortality from cancer related death, with approximately 90% of these deaths attributed to metastatic spread of the disease. There is a need to improve chemotherapy, with the dietary polyphenol curcumin, derived from turmeric, representing a potential candidate as it possess very few side effects and it has shown efficacy in mouse models. Recent advances in our understanding of tumour development have highlighted the existence of tumour initiating cells (TIC), which possess clonogenic potential, are essential for tumour growth, and represent an important therapeutic target. This study sought to determine whether curcumin in combination with oxaliplatin+5-Fluorouracil (OX+5-FU) represented a better combination for targeting TICs, using a variety of models consisting of cells derived directly from colorectal liver metastasis (CRLM). ALDHHigh activity, CD133 and CD26 were all found to mark a spheroid forming population, a method that tests for clonogenicity and selects for TICs. Curcumin significantly reduced the number of spheroids compared to DMSO, and enhanced efficacy of OX+5-FU. The only marker to decrease after treatment was ALDHHigh activity, which was also positively associated with spheroid growth. CD26 expressing cells were identified as a possible chemo-resistant population, however, this population remained unaffected by curcumin. Ex vivo analysis using explant cultures demonstrated that curcumin could significantly decrease ki67 and increase cleaved capase-3 expression, notably enhancing the effects of oxaliplatin in a proportion of patients. A pilot study was undertaken using non-obese diabetic/severe combined immunodeficient (NOD-SCID) mice to reflect a clinical regimen, and assess in vivo whether curcumin could enhance efficacy of OX+5-FU, but the results advocate the use of higher doses as little effect was seen. Overall this body of work contributes to knowledge on propagating CRLM TICs, their expression of known TIC markers, and response to curcumin.
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44

Butkewich, Susan L. "Short and long-range host finding in plum curculio (Coleoptera: Curculionidae)." 1991. https://scholarworks.umass.edu/theses/3058.

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45

"Evolutionary Biomechanics of the Rostrum of Curculio Linnaeus, 1758 (Coleoptera: Curculionidae)." Doctoral diss., 2009. http://hdl.handle.net/2286/R.I.53836.

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abstract: Weevils are among the most diverse and evolutionarily successful animal lineages on Earth. Their success is driven in part by a structure called the rostrum, which gives weevil heads a characteristic "snout-like" appearance. Nut weevils in the genus Curculio use the rostrum to drill holes into developing fruits and nuts, wherein they deposit their eggs. During oviposition this exceedingly slender structure is bent into a straightened configuration - in some species up to 90° - but does not suffer any damage during this process. The performance of the snout is explained in terms of cuticle biomechanics and rostral curvature, as presented in a series of four interconnected studies. First, a micromechanical constitutive model of the cuticle is defined to predict and reconstruct the mechanical behavior of each region in the exoskeleton. Second, the effect of increased endocuticle thickness on the stiffness and fracture strength of the rostrum is assessed using force-controlled tensile testing. In the third chapter, these studies are integrated into finite element models of the snout, demonstrating that the Curculio rostrum is only able to withstand repeated, extreme bending because of modifications to the composite structure of the cuticle in the rostral apex. Finally, interspecific differences in the differential geometry of the snout are characterized to elucidate the role of biomechanical constraint in the evolution of rostral morphology for both males and females. Together these studies highlight the significance of cuticle biomechanics - heretofore unconsidered by others - as a source of constraint on the evolution of the rostrum and the mechanobiology of the genus Curculio.
Dissertation/Thesis
Doctoral Dissertation Evolutionary Biology 2009
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46

Pinero, Jaime Cesar. "Dynamics of plum curculio, Conotrachelus nenuphar (Herbst.) (Coleoptera: Curculionidae), immigration into apple orchards." 2005. https://scholarworks.umass.edu/dissertations/AAI3179916.

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This project focused on field evaluations of synthetic host and pheromonal odor combinations for attractiveness to plum curculios, Conotrachelus nenuphar (Coleoptera: Curculionidae), with the aim of developing a monitoring device that could track the onset and extent of immigration into apple orchards, thereby maximizing plum curculio control while minimizing exposure and cost by helping growers to accurately time insecticide sprays. In a 2000 field test I screened six individual host plant volatiles, each in association with grandisoic acid (synthetic plum curculio aggregation pheromone), using panel and pyramid traps. Benzaldehyde was the most attractive host plant odor when in combination with grandisoic acid. Evaluations conducted in 2001 confirmed the attractiveness of this binary combination to both males and females across the entire period of immigration, and also revealed that benzaldehyde interacts in a synergistic manner with grandisoic acid. Additional field studies conducted in 2002 and 2003 showed that benzaldehyde at 40 mg/day of release in association with grandisoic acid at 1 mg/day of release is the most cost-effective bait combination for use in traps to monitor plum curculio immigration. I also investigated temporal dynamics of plum curculio immigration into an unsprayed section of an apple orchard over a five-year period using traps. My main goal was to determine relationships among the timing of immigration, temperature and phenological tree stage. Based on my data, I propose a pre- and a post-petal-fall period of immigration, each of which is influenced to a different extent by spring temperature. Thermal constants (expressed in Degree Days [DD] base 6.1°C, computed starting January 1st) for the start of immigration, 50th and 80th percentile of cumulative captures were 113, 249 and 412 DD, respectively. Some spatial aspects of plum curculio immigration were also studied in commercial apple orchards over a two-year period. By petal fall, most adults were found on perimeter-row trees in sprayed blocks having large trees (M.7 rootstock), but more adults were found inside of blocks than on perimeter-row trees if blocks had small trees (M.9 rootstock). Plum curculios were able to overwinter inside blocks, regardless of the presence or absence of weeds beneath trees.
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47

Lan, Zhiwen. "Ecology and management of peach scab (Cladosporium carpophilum) and plum curculio (Conotrachelus nenuphar) in the Southeastern United States." 2003. http://purl.galileo.usg.edu/uga%5Fetd/lan%5Fzhiwen%5F200305%5Fms.

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Thesis (M.S.)--University of Georgia, 2003.
Directed by Harald Scherm. Includes an article published in Plant disease, and articles submitted to Environmental entomology, and Phytapathology. Includes bibliographical references.
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48

Rohlfs, Doris Andrea. "A study of acorn feeding insects : filbert weevil (Curculio occidentis (Casey)) and filbertworm (Cydia latiferreana (Walsingham)) on Garry oak (Quercus garryana) (Dougl.) in the southeastern Vancouver Island area." Thesis, 1999. http://hdl.handle.net/2429/9149.

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The Garry oak (Quercus garryana) Dougl. is the only oak native to British Columbia and is one of the more distinct and stately trees growing in the Greater Victoria area. The Garry oak meadow ecosystem is unique and rich, with the largest number of rare plant species of any ecosystem not only in British Columbia, but in Canada. Since acorns are vital to maintain future generations of Garry oak trees, the insects that attack and damage these acorns are of interest. Garry oak acorns were collected from June to September in 1996, 1997 and 1998 to determine the abundance and spatial distribution of acorns infested by the filbert weevil (Curculio occidentis (Casey)) (Coleoptera: Curculionidae) and filbertworm (Cydia latiferreana (Walsingham)) (Lepidoptera: Olethreutidae) at 10 locations in the Greater Victoria area. The biology of C. occidentis was studied by laboratory rearings from 1997 through 1998. Both C. occidentis and C. latiferreana infested a large portion of acorns in 1996, 1997 and 1998, exhibiting an inverse trend of infestation level to crop abundance. This trend was more evident for the filbertworm, than the filbert weevil. Acorn crops in 1996 and 1997 were light, and in 1998 was heavy, a mast year. Dissection of 10,879 acorns showed the combined infestation rates by the two insects were 80.7%, 75.0% and 51.3% in 1996, 1997 and 1998, respectively. Of these acorns, the filbert weevil consistently infested more acorns than the filbertworm. Significantly more filbert weevil infested acorns occurred in the lower- than the middle- and upper-portion of the sample trees in 1998, but not in 1997. The proportion of acorns infested by the filbert weevil and filbertworm did not vary by compass direction (south, northeast and northwest) in either 1997 or 1998. Strata infestations were not examined in 1996. Although infestation by these two insects was high, it was shown that even moderately damaged acorns, with up to 50% damage to the cotyledon, still have the potential to germinate. In 1996,1997 and 1998, 51.4%, 49.5% and 77.6% of acorns, respectively, had less than 50% damage to the acorn cotyledon. Filbert weevil adults emerge in June through September to oviposit into the forming Garry oak acorns. Laboratory reared larvae feed, on average, for 5 Vi weeks, completing 4 larval instars during this time. The larvae overwinter in the 4th instar, and pupate in the spring. The pupal stage last approximately 12 days, with the callow adults requiring an additional 10.3 days to harden and gain full coloring. Females are larger than males in body length, body width, and rostrum length. Filbertworm eggs were rarely seen during this study. Larvae were observed in acorns beginning mid-July and emergence holes were found approximately one month later. Control measures for the filbert weevil and the filbertworm are not recommended because even moderately damaged acorns are capable of germinating. Thus, the impact of damage by these two insects is less than it appears. The natural cycle of poor and mast crops of Garry oak acorns acts as a natural control for these two insect populations.
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49

Zhang, Wen Liang, and 張溫良. "Phytochemical and pharmacological studies on curculigo capitulata." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/31427509282965158274.

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50

Ze, Chen Chu, and 陳楚澤. "Xanthine Oxidase and α-Glucosidase Inhibition of Curcumin and Curcumin Analogs." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/y83s8x.

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碩士
輔仁大學
食品科學系碩士班
103
Curcumin is a constituent from root and stem of family Zingiberaceae and Araceae. It has been used as a natural colorant in food industry. Curcumin has a great value in food and medicine, and it has been reported that curcumin could inhibit the activities of xanthine oxidase (XO) and α-glucosidase that make curcumin can be used for treatment of gout and diabetes. Chemical synthesis, which can change the structure of component, can enhance the activities, even create a new one. Therefore, the objective of this research is to evaluate the characterization of curcumin and its analogs as XO and α-glucosidase inhibitors. In this study, after screening XO and α-glucosidase inhibition, the components which have high inhibitory activities were calculated their half-maximal inhibitory concentration (IC50) and enzyme inhibitory kinetics. In order to calculating the inhibitory reaction constant, a docking algorithm simulates binding position between enzyme and inhibitors. The results showed that among all the curcumin and its analogs, CM-F had the strongest anti-oxidant activity with a half-maximal effective concentration (EC50) of 9.39 ± 0.16 μM, which was better than vitamin E (EC50=17.03 ± 0.09 μM). It also had a good XO inhibitory activity, and its IC50 value against XO was 6.14 ± 0.38 μM. The enzyme kinetic result showed it was competitive inhibition. As for α-glucosidase, CM-1 and CM-2 have good α-glucosidase inhibitory activities with the IC50 value of 21.06 ± 0.92 μM and 5.95 ± 0.09 μM, of which kinetic study indicates that both CM-1 and CM-2 are mix-competitive inhibitors on α-glucosidase. Furthermore, docking simulation showed there are 5 hydrogen bonds between XO and CM-F. However, only 1 and 2 hydrogen bonds involved in CM-1 and CM-2 binding to α-glucosidase, respectively. Accordingly, analogs of curcumin have the potentials using in the gout or diabetes patients.
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