Dissertations / Theses: 'Wounding'

7

Carter, Lauralyn B. "Induction of phototoxic acetylenes in carthamus tinctorius by mechanical wounding." FIU Digital Commons, 1999. http://digitalcommons.fiu.edu/etd/2061.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Sujipuli, Kawee. "Identification of miRNAs produced in response to wounding Arabidopsis thaliana." Thesis, University of East Anglia, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.533707.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Chung, Thanh Tu. "Effect of wounding on cell wall hydrolase expression in fruit." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415488.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

De, Lange Bev. "Wounding and healing as paradox: towards the visual articulation of synthesis." Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/1655.

Full text

Abstract:

The very notion of wounding can be argued to imply a process of healing. Indeed some wounds are at the outset designed to be instruments of healing. As ten years of my professional life were spent assisting in the surgical creation of such „wounds‟ in an operating theatre it is from this memory timeframe that I initiated the process of developing visual equivalents that become reflective of both wounding and healing. The operation theatre was also an environment from which I developed increased awareness of mind or psyche as an entity conceptually comprising both conscious and unconscious components. Within this context, it can be argued that the patient‟s state of mind moves between consciousness and forms of unconsciousness induced through anaesthesia. Through research into the writings of the psychoanalyst Carl Jung, I began to develop a greater understanding of the concepts surrounding the conscious and unconscious mind in relation to the development of consciousness as well as to the integration of opposites. It is from this understanding of a dynamic process within the mind itself that I have attempted to develop visual signifiers of paradox in order to give expression to symbols that are reflective of these processes and in so doing indicate the psychological journey towards synthesis and individuation.

APA, Harvard, Vancouver, ISO, and other styles

11

Morker, Krishna Hasmukh. "Interactions between the responses of light and wounding in Arabidopsis Thaliana." Thesis, Lancaster University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.533107.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Sözen, Cécile. "Characterization of a MAPK module involved in Arabidopsis response to wounding." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS472/document.

Full text

Abstract:

Les plantes ne pouvant pas se déplacer sont continuellement soumises aux stress environnementaux. La blessure, l’un des stress les plus fréquents auxquels la plante est soumise, peut causer d’important dégâts et faciliter l’entrée de pathogène dans les tissus de la plante. Pour répondre efficacement à la blessure, la plante a développé des mécanismes lui permettant de guérir ses tissus endommagés et d’empêcher l’infection pathogène. Les stress environnementaux sont perçus grâce à la présence de récepteurs spécifiques activant des voies de signalisation qui, à terme, conduisent à la mise en place de réponses de défense. Les modules de MAPK, composés de 3 kinases (MAP3K, MAP2K et MAPK) activées en cascades, représentent d’importantes voies de signalisation impliquées en réponse à divers stress biotiques et abiotiques. Grâce aux approches de tests de phosphorylation in vitro très maîtrisées dans le groupe « Stress signaling », j’ai pu identifier un module MAPK impliquant la MAP2K MKK3 et les MAPKs du groupe C (MPK1, 2, 7 et 14) activé par la blessure. Les MAP3Ks du sous-clade III (MAP3K13 à 20) sont transcriptionnellement induites par divers stress ce qui semble être un mécanisme assez conservé. Certains membres du sous-clade III sont induits par la blessure et parmi eux la MAP3K14 semble avoir un rôle majeur en amont du module MKK3/MPK1-2-7-14. Enfin, j’ai pu montrer que l’acide jasmonique (JA), une phytohormone importante produite en réponse à la blessure, tient un rôle important en amont du module. Ce-dernier est également activé en réponse à l’insecte herbivore Spodoptera littoralis et au champignon nécrotrophe Botrytis cinerea. Dans le contexte de blessure par l’insecte herbivore, MKK3 semble réguler la production de deux phytohormones, le JA et l’Acide Salicylique (SA) Plants are sessile organisms. They have to cope continuously with environmental stresses. Injury, one of the most frequent stress conditions that plants must face may cause harsh damages to the plant tissues and facilitate the entry of pathogens. Therefore, plants have evolved mechanisms to respond efficiently to wounding by healing damaged tissues and preventing further pathogen infection. Wounding is a complex stress which is perceived by specific receptors which activate signaling pathways leading to those responses. Mitogen-Activated Protein Kinases modules are composed of 3 kinases (MAP3K, MAP2K and MAPK) activated in cascade and represent important signaling pathways involved in response to various biotic and abiotic stresses as well as in developmental processes. During my Ph.D I identified a MAPK module activated 30 minutes after wounding and involving the MAP2K MKK3 acting upstream of C-group MAPKs MPK1-2-7-14. In the past, the laboratory has shown that this module is dependent on the transcriptional regulation of sub-clade III MAP3Ks (MAP3K13 to 20). Some were found induced by wounding and among them MAP3K14 seems to have an important role upstream MKK3/C-group MAPKs. Finally I was able to show that Jasmonic Acid (JA), a major phytohormone produced upon wounding and involved in the mediation of defense responses, was shown to have an important role upstream the MKK3/C-group MAPKs module. The module is also activated by the herbivore Spodoptera littoralis and the necrotrophic fungus Botrytis cinerea. Upon insect feeding, MKK3 negatively regulates JA and SA levels. My work helped to better understand stress signaling events occurring upon wounding

APA, Harvard, Vancouver, ISO, and other styles

13

Aggelis, Alexandros. "Gene expression in ripening melon (Cucumis melo L.)." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319646.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Shibani, Nagla Mohamed. "Proteomic analysis of host responses to wounding and aphid infestation in pea." Thesis, University of the West of England, Bristol, 2017. http://eprints.uwe.ac.uk/31778/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Gangnuss, Samantha. "Characterization of AP-1 transcription factor activation by wounding in fetal skin." Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phg1974.pdf.

Full text

Abstract:

"June 2002" Bibliography: leaves 144-170. Fetal skin has a unique ability to re-epithelialize a wound in the absence of dermal substrata, although this capacity is lost between embryonic day 17 (E17) and day 19 of gestation (E19) in the rat. This study seeks to identify the molecular signalling events induced by wounding in E17 and E19 skin, as well as the role these events play in the prenatal switch in re-epithelialization mechanisms in fetal skin.

APA, Harvard, Vancouver, ISO, and other styles

16

Lin, Gongyu. "Molecular responses of Medicago truncatula to wounding and Spodoptera exigua caterpillar herbivory." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97147.

Full text

Abstract:

Mechanical wounding and insect feeding induce different transcriptional profiles in plants (Reymond et al. 2000). However, the molecular mechanisms underlying this difference are unclear. By using caterpillars with or without labial salivary secretions, I hope to understand the role of salivary elicitors in plant-insect interactions. Five caterpillar-specific Medicago truncatula genes were previously identified by cDNA-amplified fragment length polymorphism analysis (Darwish et al. 2008). In the present project, temporal transcript profiles of these five genes in response to wounding and Spodoptera exigua caterpillar herbivory were investigated. The expression of the gene encoding a RING zinc finger protein (MtRFP) is significantly reduced 10 h after mechanical wounding or caterpillar herbivory. Herbivory of caterpillars with intact labial salivary secretions significantly decreases the transcription of MtRFP in comparison to mechanical wounding. Our study suggests that labial saliva of S. exigua caterpillars is important for M. truncatula to differentiate between mechanical wounding and insect feeding. L'alimentation des insectes ainsi que les dommages physiques induisent différentes réactions transcriptionnelles chez les plantes (Reymond et al. 2000). Cependant, les mécanismes moléculaires qui sont à leur base restent peu connus. En utilisant des chenilles ayant les sécrétions salivaires intactes ou abîmées, nous espérons comprendre le rôle des molécules salivaires dans les interactions entres plantes et insectes. Cinq gènes provenant du Medicago truncatula et specifique à l'herbivorie par les chenilles furent identifiés en utilisant la technique de profilage génétique, cDNA-AFLP (Darwish et al. 2008). Dans cette étude, nous avons analysé de façon temporelle les réactions transcriptionnelles de ces gènes lorsque les plantes étaient endommagées physiquement et aussi par herbivorie des chenilles. Dans les deux cas, l'encodage génétique de la protéine (MtRFP) fut significativement régulé à la baisse 10 heures après le traitement. En fait, les chenilles ayant les sécrétions salivaires labiales intactes répriment l'expression du MtRFP comparativement à celles avec dommage. Ce mémoire montre que la salive labiale des chenilles est importante car elle permet au M. truncatula de différencier entre les blessures mécaniques et l'alimentation des insectes.

APA, Harvard, Vancouver, ISO, and other styles

17

Moody, Steven James. "MAP kinase activity in the wound response of tomato." Thesis, University of York, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325646.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Van, der Merwe Nicholas Geoffrey. "Skinning the surface : exploring the textuality of the skin through figurations of wounding and healing." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97158.

Full text

Abstract:

Thesis (MA)--Stellenbosch University, 2015. ENGLISH ABSTRACT: This thesis is an exploration of the textuality of the skin, and how we approach and read wounds and scars. My discussion approaches the skin through the frame of surface reading to address three interconnected but seemingly disparate areas; namely American slavery, atrocities committed by the Lord’s Resistance Army, and self-mutilation. These areas all share the trope of the wound, and my approach is thus interdisciplinary in nature. I begin my discussion with Toni Morrison’s Beloved, focusing on the manner in which the extreme violence the characters suffer plays an instrumental role in their ability to reconcile themselves with their pasts. I focus specifically on the scars on Sethe’s back that resemble a tree, and how this tree links all of the characters together in their desire to re-member themselves. I then move to the Lord’s Resistance Army and how their mutilations of the civilian population serve a communicative function. I explore how we read images of atrocity, and how many of these images are framed and manipulated in order to garner attention. From there, I move to Kony 2012, the viral ‘documentary’ that drew the world’s attention and criticism for its gross misrepresentation of Africa and its indulgence in the stereotypes that present Africans as passive victims in need of saving. Finally, I discuss the phenomenon of self-mutilation and how the cuts and scars reveal how language is rendered incapable of expressing the inner pain and suffering of cutters. Often, these wounds and scars are misinterpreted as failed suicide attempts, an interpretation which completely ignores the expression of the symptom revealed on the surface. The negative stigma attached to self-mutilation hinders communication between those who cut and those who do not. In order for communication to be successful, all preconceived notions of what self-mutilation is need to be abandoned. AFRIKAANSE OPSOMMING: Hierdie tesis is ŉ verkenning van die tekstualiteit van die vel, en hoe ons wonde en littekens benader en lees. My bespreking benader die vel deur die lens van oppervlak-analise om drie onderling verbonde dog uiteenlopende areas aan te spreek, naamlik, Amerikanse slawerny, gruweldade wat deur die Lord’s Resistance Army gepleeg is, en self-mutilasie. Dié areas deel saam die troop van die wond, en my benadering is dus interdissiplinêr van aard. My bespreking begin met Toni Morrison se Beloved met die fokus op die manier wat die uitermatige geweld waaraan die karakters onderwerp word ŉ integrale rol speel in hul vermoë om vrede te maak met hul verledes. Ek fokus spesifiek op die littekens op Sethe se rug wat soos ŉ boom lyk, en hoe dié boom al die karakters aan mekaar skakel in hul begeerte om hulself te ‘her-versamel’ en her-onthou. Ek beweeg dan aan na die Lord’s Resistance Army en hoe hulle verminking van die burgerbevolking ŉ kommunikatiewe funksie vervul. Ek verken hoe ons beelde van gruwel lees, en hoe baie van dié beelde geraam en gemanipuleer word om aandag te trek. Van daar beweeg ek aan na Kony 2012, die gewilde web-dokumentêr wat die wêreld se aandag en kritiek uitgelok het as gevolg van die totale wanvoorstelling wat dit van Afrika getoon het, asook die onnadenkenheid van die documentêr in terme van Afrikane wat as passiewe slagoffers wat redding benodig gestereotipeer word. Oplaas bespreek ek die fenomeen van self-mutilasie en hoe die snye en littekens ŉ openbaring maak van die ontoereikendhied van taal om innerlike pyn en lyding van snyers uit te druk. Dikwels word die wonde en littekens verkeerd geïnterpreteer as mislukte selfmoordpogings, ŉ interpretasie wat die uitdrukking van die simptome wat op die oppervalk blootgelê word ignoreer. Die negatiewe stigma wat aan self-mutilasie gekoppel word belemmer kommunikasie tussen snyers en nie-snyers. Kommunikasie kan net suksesvol wees as alle vooropgesette idees van wat self-mutilasie is agtergelaat word.

APA, Harvard, Vancouver, ISO, and other styles

19

Ballesteros, J. A., M. Stoffel, J. M. Bodoque, M. Bollschweiler, O. Hitz, and A. Díez-Herrero. "Changes In Wood Anatomy In Tree Rings Of Pinus Pinaster Ait. Following Wounding By Flash Floods." Tree-Ring Society, 2010. http://hdl.handle.net/10150/622618.

Full text

Abstract:

This paper analyzes the anatomical response of Pinus pinaster Ait. following wounding by flash floods. A total of 14 wood samples were taken from 14 different scarred trees located on the river banks of the Arroyo Cabrera torrent (Spanish Central System). In addition, 20 increment cores were collected from undisturbed and healthy P. pinaster trees to build a local reference chronology. For the injured trees, analysis focused on growth changes in early earlywood (EE) tracheids, namely on differences in (i) lumen size; (ii) cell-wall percentage and cell-wall thickness; (iii) radial length and tangential width of tracheids; as well as (iv) in the abundance of resin ducts in earlywood (EW) and latewood (LW) following wounding. Results indicate that tissues bordering flash-flood wounds are characterized by reduced growth rates and a decrease of EE tracheid lumen area by 51%. In addition, cell-wall percentage increases by 34% in the increment rings formed after the event and significant changes are observed in the radial length and tangential width of EE tracheids. Observations on resin ducts do not yield any significant results. Based on these anatomical parameters, detecting and dating past flash-flood events in growth rings is now possible for Mediterranean species, specifically P. pinaster.

APA, Harvard, Vancouver, ISO, and other styles

20

Myung, Kyung. "BIOSYNTHESIS OF trans-2-HEXENAL IN RESPONSE TO WOUNDING IN STRAWBERRY FRUIT AND INTERACTION OF trans-2-HEXENAL WITH BOTRYTIS CINEREA." UKnowledge, 2005. http://uknowledge.uky.edu/gradschool_diss/445.

Full text

Abstract:

Intact strawberry fruit did not produce detectable t-2-H which is derived from -linolenic acid (18:3). However, in response to wounding by gentle bruising, strawberry fruit emitted t-2-H with the largest quantity produced within 10 min following injury. The level of total lipid 18:3 in the fruit increased two-fold in response to wounding whereas free 18:3 declined slightly (about 30%). At 10 min following wounding, fruit exhibited a 25% increase in 13-lipoxygenase (LOX) activity, which leads to the production of 13-hydroperoxyoctadecatrienoic acid (13-HPOT) from 18:3. The activity of hydroperoxide lyase (HPL), which catalyzes formation of cis-3-hexenal (c-3-H), the precursor of t-2-H, from 13-HPOT, increased two-fold at 10 min after wounding. Thus, within 15 min after wounding, free 18:3 substrate availability and the activity of two key enzymes, LOX and HPL, changed in a manner consistent with increased t-2-H biosynthesis. The site and mode of interaction of C6 aldehydes with Botrytis cinerea, a common pathogen of many plant species, was characterized using radiolabeled six carbon (C6) aldehydes, including c-3-H and t-2-H. An approximately 25% molar conversion of 18:3 to C6 aldehydes was obtained by enzymatic manipulation with LOX and HPL extracts. Following exposure of Botrytis cultures to radiolabeled aldehydes, radiolabeled aldehydes were recovered in protein fractions, but not in the lipid fraction. They were incorporated into conidia at a 20-fold higher level than mycelia (per mg fresh weight). About 95% of the radiolabeled aldehyde was recovered in proteins on the surface (wash protein) of the fungal tissue, while 5% was from protein in internal tissue (cell wall and membrane and cytosol). Supplementing radiolabeled aldehydes with nonradiolabled C6 aldehydes to increase the vapor phase concentration affected distribution of radiolabel in each protein fraction. The t-2-H at both 5.4 and 85.6 mol affected protein expression patterns, changing the intensity of expression in over one third of all proteins. Both up- and down-regulation of specific proteins were observed. Though five proteins of interest were analyzed, their identities were not determined. However, the data indicate a clear effect of t-2-H on protein expression in Botrytis cinerea.

APA, Harvard, Vancouver, ISO, and other styles

21

Williams, Vernetta K. "Honor - a double-edged sword : an examination of the South's "culture of honor" wounding of two races." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0001978.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Oliveira, Lucilene Silva de. "Postharvest role of jasmonic acid and wounding on expression of defense related metabolism in sugar beet roots." Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/8354.

Full text

Abstract:

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2016-08-18T11:53:27Z No. of bitstreams: 1 texto completo.pdf: 846703 bytes, checksum: 3c42f8564d8a86d839a5d1d19109efad (MD5) Made available in DSpace on 2016-08-18T11:53:27Z (GMT). No. of bitstreams: 1 texto completo.pdf: 846703 bytes, checksum: 3c42f8564d8a86d839a5d1d19109efad (MD5) Previous issue date: 2016-03-18 Conselho Nacional de Desenvolvimento Científico e Tecnológico Jasmonatos (JA) podem atuar como um indutor da expressão de genes contra estresse biótico e abiótico através de um processo denominado “prime state”. Aplicação de JA tem mostrado reduzir o apodrecimento de tecidos e controlar doenças pós-colheita em raízes de beterraba açucareira. Entretanto, os mecanismos envolvidos na indução de defesa na pós-colheita de raízes de beterraba açucareira através da aplicação do JA são desconhecidos. Consequentemente, foi investigado os mecanismos induzidos pelo JA, ao qual protege as raízes durante o armazenamento, identificando e caracterizando genes que são alterados pelo tratamento com JA. O tratamento de raízes de beterraba com 10 μM de JA resultou na alteração significativa da expressão de unigenes. O sequenciamento do mRNA revelou que 30 e 49 genes com potencial de defesa foram upregulated para 2 e 60 dias, respectivamente, após o tratamento com JA. Após 2 dias de tratamento, os níveis de peroxidase, cinamato-4-hidroxilase, quitinase ácida, lacase, proteína de resistência nbs-Irr, proteína relacionada a patogênese da família da taumatina, inibidor de protease e β-glucosidase ( variação de 1.8 a 8.3 vezes) apresentaram maior expressão em raízes de beterraba açucareira tratadas que as do controle. Peroxidase, cinnamato-4- hidroxilase e cc-nbs-Irr resistant protein também foram up-regulated 60 dias após a aplicação de JA. Os unigenes upregulated, em ambos os dias avaliados, são relacionados a rotas de metabólicas de biossíntese de compostos secundários, aumento da resistência da parede celular, assim como proteínas relacionadas à interação planta-patógeno. Assim, o presente trabalho sugere que o tratamento com JA pode induzir o “prime state” em beterraba açucareira, induzido uma série de genes relacionados a defesa de plantas. Incluindo enzimas relacionadas a biossíntese de metabólicos secundários e proteínas relacionas a patogêneses. O JA também aumentou a habilidade de células reconhecer patógenos , qual pode resultar em rápida ativação de respostas imune e reduzir a susceptibilidade das raízes a doenças pós- colheita. Em adição as perdas devido ao apodrecimento no armazenamento das raízes, é de extrema importância evitar as perdas de açúcares durante o crescimento. O ataque por larvas de mosca de raízes de beterraba açucareira é um dos danos que reduz significativamente a produção de raízes e o conteúdo de sacarose, podendo devastar campos de produção. Assim, o estudo de mecanismos de resistência é essencial para prover novas estratégias de controle e reuduzir a aplicação de inseticidas. Neste trabalho foi investigado se a resistência de alguns genótipos é alcançada através da ativação da quitinase, peroxidase e polifenoloxidase. Raízes de nove genótipos de beterraba açucareira, susceptível ou resistente à larva de mosca de raízes de beterraba açucareira, foram feridas quatro semanas após o plantio para mimetizar o ataque por estas larvas. Os resultados mostraram a atividade das enzimas antioxidantes, peroxidase e polifenoloxidase, não está correlacionada a resistência de beterraba açucareira a larva de mosca de raízes de beterraba açucareira. A atividade da quitinase foi signicativamente reduzida em alguns genótipos após o ferimento, entretanto não foi encontrado diferença significativa entre genótipos resistente e susceptível de beterraba açucareira. Jasmonate (JA) can act as an inducer expression of defense genes against biotic and abiotic stress by process of priming plant. Exogenous application of JA has been shown to reduce rotted tissue and control postharvest pathogen in sugarbeet roots. However, the mechanism involved in the postharvest induction of defense by JA in sugarbeet roots is unknown. Consequently, we investigated the JA-induced mechanisms which protect roots from storage pathogens by identifying and characterizing genes that are altered by JA treatment. JA (10 μM) treatment to sugarbeet roots resulted alteration significant of unigenes expression. RNA-Seq data showed that 30 and 49 putative defense genes were upregulated at 2 and 60 days after JA-treatment, respectively. In sugarbeet roots, peroxidases, cinnamate-4-hydroxilase, chitinase acid, laccases, nbs-Irr resistant, pathogen-related thaumatin family protein, proteinase inhibitor and β- glucosidase were found at higher levels (fold change ranged from 1.8 to 8.3) in treated than control roots at 2 d subsequent to JA-application. At 60 days after JA treatment observed that peroxidase, chitinase, cinnamate-4 hydroxilase and cc-nbs-Irr resistant protein were also up-regulated. These upregulated unigenes are related with biosynthesis of secondary metabolites, cell wall reinforcement, as well as for plant- pathogen interaction. Thus, the present study suggests that JA treatment could prime sugarbeet inducting a series of defense genes, including defense-related proteins and key enzymes related secondary metabolites. JA also increased the ability of sugarbeet cells to recognize pathogen which may result faster activation of immune response and then reduction of infection and susceptibility. In addition to rotted losses in rot storage it is extremely importance to avoid losses during sugarbeet growth. Insect attack by sugarbeet root magoot is one of damage that significantly reduces root yield and sucrose content and can devastate individual fields. Thus, study of resistance mechanism is essential to provide new control strategies and reduce insecticides spray. We investigated if resistance of some genotypes is achieved through activation of chitinase, peroxidase and polyphenoloxidase. Root of nine genotypes sugarbeet, susceptible and resistant to maggot fly, were wounding 4 weeks after planting to mimic maggot attack. The results showed neither peroxidase nor polyphenol oxidase activity is correlated to maggot fly resistant in sugarbeet roots. We observed that chitinase activity was significantly reduced for some genotypes after wounding, although no significance difference was found between resistant and susceptible sugarbeet genotypes.

APA, Harvard, Vancouver, ISO, and other styles

23

Yung, Mei Hing. "Regulatory functions of two Cis-elements on tissue-specific and wounding responsive activation of Phaseolus vulgaris PAL2 promoter." Thesis, University of East Anglia, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361483.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Griessel, Janette Myrna. "Die rol van vrees by die swaarmoedige adolessent: 'n pastorale studie." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9045.

Full text

Abstract:

The focal point in this study is the pastoral counselling and care of the heavy-hearted or depressed teenager who struggles with fear. The basic-theoretical perspective (chapter 2) emphasises the importance of counselling of the teenager from a Biblical viewpoint to be a testimony of the greatness of God. The fear that the teenager suffers from, is also described as the enemy who poses a threat to the inner being of the person. Therefore this type of threat can often lead to the total destruction of the inner being of a teenager. An intimate relationship with God enables a person to seek refuge in God from any problem he or she might experience. This relationship with God will guarantee the person of His full protection. It is of the utmost importance for an adolescent to seek wisdom and follow their parental guidelines. It is also important for young people to make the correct choices to enjoy the protection and guidance of God. They must also continually ponder over and treasure the guidance of their parents. The meta-theoretical perspective (chapters 3 and 4) focusses on the contribution and applicability of neighbouring sciences such as psychology, sociology and criminology. It was proven among other aspects that emotional hurt in different areas, was the reason for serious damage to the inner being of teenagers. In many cases the result was amongst others an identity crisis as well as a low self-esteem. At the end of this section temporary guidelines are suggested to aid the counselling of the depressed teenager who suffers from excessive fear. The section on empirical research (chapter 4) as a sub-section of the meta-theoretical research, introduced four case-studies regarding teenagers who had traumatic experiences and as a result suffered from multiple negative emotions. In all four cases it became evident that these emotions were eventually the result of a life without any joy or meaning. A very important factor regarding their negative self-image or self-perception seemed to be the absence of role-models. The further result repeatedly seemed to be a distorted relationship with God and fellow-men. In the section on practical-theoretical perspectives (chapter 5) an attempt is made to formulate an adapted practice theory through a hermeneutical interaction between basis-theoretical guidelines and meta-theoretical perspectives that can be applied to the guidance of the emotionally wounded teenager who is wrestling with fear. Included hereby is then a proposed model with some practical guidelines. Thesis (MA (Pastoral Studies))--North-West University, Potchefstroom Campus, 2013.

APA, Harvard, Vancouver, ISO, and other styles

25

Alegria, Carla Sofia Marques. "Heat shock and UV-C abiotic stress treatments as alternative tools to promote fresh-cut carrot quality and shelf-life." Doctoral thesis, ISA/UL, 2015. http://hdl.handle.net/10400.5/9266.

Full text

Abstract:

Doutoramento em Engenharia Alimentar - Instituto Superior de Agronomia Abiotic stress treatments, heat shock (HS_100 ºC/45 s) and UV-C (0.1-5 kJ.m-2), and two passive modified atmosphere packaging conditions were evaluated under the hurdle concept as alternative approaches to the standard processing of fresh-cut carrot (FCC). The significant phenolic accumulation, via phenylalanine-ammonia lyase activation, showed to be independent on key factors contributing to raw material bioactivity, cultivar and crop season, but dependent on treatments intensity (HS_[100 ºC/45 s], UV-C_[2.5 kJ.m-2]) and on oxygen availability (>2%). The low decontamination efficiency of UV-C_[2.5 kJ.m-2] as single hurdle was similar (p>0.05) to that of sodium hypochlorite (<1 Log10 cycle in aerobic mesophilic microflora) and was responsible for FCC early sensorial rejection (<7 days), regardless packaging conditions. The simultaneous effects on microbiological control and reduced metabolic rates yielded by HS_[100 ºC/45 s] significantly contributed to the preservation of FCC sensorial quality allowing the full recovery (100%) of raw materials’ phenolic levels (≥5 days, 5 ºC), with no synergic effects in the combination with UV-C, resulting in FCC shelf-life extension by two-fold (14 days, 5 ºC) when using a bi-oriented polypropylene micro-perforated film FCT

APA, Harvard, Vancouver, ISO, and other styles

26

Tsolaki, Ioanna. "Connective Tissue Grafts and Surgical Delay: Clinical and Biochemical Characterization." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1339814710.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Lewandowska, Milena [Verfasser], Ivo [Akademischer Betreuer] Feußner, Andrea [Gutachter] Polle, and Ljerka [Gutachter] Kunst. "Function of Cuticular Waxes in Plant Response to Wounding / Milena Lewandowska ; Gutachter: Andrea Polle, Ljerka Kunst ; Betreuer: Ivo Feußner." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://d-nb.info/1212660684/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Zabaras, Dimitrios, University of Western Sydney, of Science Technology and Environment College, and of Science Food and Horticulture School. "Determination of induced changes in foliar emissions of terpene-accumulating plants." THESIS_CSTE_SFH_Zabaras_D.xml, 2003. http://handle.uws.edu.au:8081/1959.7/809.

Full text

Abstract:

Stress-induced changes in the emissions of volatiles from many economically-important plants have been demonstrated in studies over the past decade. Plants such as cotton and corn change both the composition and concentration of their emissions when subjected to wounding, herbivory and pathogen attack. Terpene-accumulating plants have been overlooked as potential objects of such studies although work on conifers has shown that species rich in constitutive defences can also exhibit induced responses. The aim of this study was to investigate whether terpene-accumulating plants respond to stress by altering their foliar emissions qualitatively and/or quantitatively. Species examined included Salvia officinalis (common sage), Melaleuca alternifolia (Australian tea tree) and Ocimum minimum (Bush basil). An experimental design was developed to eliminate factors such as leaf ontogeny that can affect the obtained results and complicate their interpretation. Small-scale solvent extraction and HS-SPME-based techniques were also developed; they enabled the quantitative determination of treatment-induced changes over periods ranging from 10 minutes to 6 months. Treatment of plants included mechanical wounding, herbivory, pathogen attack and chemical elicitation. Overall, statistically significant induced-changes were observed for both leaf-oil composition and concentration. The response of the different species used varied. O. minimum exhibited the greatest compositional changes whilst M. alternifolia was the only species for which oil-concentration changes were observed. The demonstrated changes were not as great as those reported in similar studies with non-terpene producing plants. The results indicate that the high metabolic costs associated with the production and storage of constitutive defences may be responsible for the limited induction of further defensive responses Doctor of Philosophy (PhD)

APA, Harvard, Vancouver, ISO, and other styles

29

Sachan, Nita. "IDENTIFICATION OF SIGNALING FACTORS INVOLVED IN THE REGULATION OF ALKALOID METABOLISM IN N. TABACUM." UKnowledge, 2004. http://uknowledge.uky.edu/gradschool_diss/442.

Full text

Abstract:

To identify the signaling mechanisms and components that are involved in regulation of a promoter for a gene involved in a secondary pathway I studied the nicotinic alkaloid biosynthetic pathway using various N. tabacum tissues. Nicotine and tropane alkaloids are widely known to be synthesized predominantly in the roots of species that produce pyrrolinium ring containing alkaloids. Putrescine Nmethyltransferase (PMT) catalyzes the first committed step in the biosynthesis of these alkaloid secondary products and earlier studies have indicated that PMT gene expression is restricted to root tissue in Solanaceae plants. To further elucidate the factors that govern the regulation of alkaloid synthesis, expression patterns dictated by the 5'-flanking region of one of the members of the PMT -gene family, NsPMT3, using the b-glucuronidase (GUS) reporter gene were examined. Various treatments were used to characterize the nature of signaling in various tissues of seedlings, whole plants and callus. High expression levels were detected in root tissue and no expression was detected in leaves, in agreement with previous studies. However, mechanically wounded leaves resulted in highly localized PMT expression. This wound-induced expression was transient, with maximum levels occurring immediately after wounding and diminishing after approximately 24 h. RT-PCR analysis of mRNA isolated from wild-type plants also indicated upregulation of PMT expression in leaves upon wounding as well as very low transcript levels in unwounded leaves. Low levels of PMT activity were detected in leaf tissue, and this activity did not increase significantly upon wounding. Transgenic callus material showed strong repression of PMT promoter activity in the presence of light and auxin, whereas dark conditions and the absence of auxin upregulated PMT promoter activity. Reactive oxygen species have been implicated in signaling. When treated with the scavengers of reactive oxygen species (ROS), dimethylthiourea (DMTU) or catalase, tobacco callus tissue, which displays highly repressed alkaloid synthesis under normal culture conditions in the light, exhibited significant induction of PMT promoter activity and alkaloid accumulation. It is thought that light repression signals through an ROS intermediate to affect changes in alkaloid pathway gene expression. Upregulation of PMT-promoter activity was observed upon treatment with JA (jasmonic acid) or darkness in roots of very young transgenic seedlings. Treatment with auxin, salicylic acid (SA) and H2O2, on the other hand, was found to highly repress PMT promoter activity. Action of other ROS such as nitric oxide and superoxide radicals on PMT expression is not clear but probably play less of a role, compared to H2O2. Consistent with this content ion, treatment with light or glucose oxidase (GOX) and glucose to generate H2O2, also repressed alkaloid accumulation, and treatment of seedlings to dark conditions, the ROS scavenger DMTU, or jasmonic acid resulted in alkaloid accumulation. Long distance signaling from leaves to roots is also suspected to involve ROS, as leaves treated with GOX and glucose exhibited repressed PMT promoter activity in roots. The responses of the PMT promoter to auxin, salicylic acid and H2O2 treatments were conserved as sho wn by similar responses of the N. tabacum PMT promoter when examined in transgenic Arabidopsis, thereby suggesting that these molecules signal through a conserved mechanism. Thus, ROS is strongly implicated in acting as an intermediate in these signaling processes with H2O2 proposed as a major signaling component.

APA, Harvard, Vancouver, ISO, and other styles

30

Perotti, Janieli Cristina. "Respostas fisiológicas e metabólicas frente a estresses em Eucalyptus Grandis X E. Urophylla e Araucaria Anfustifolia." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/131757.

Full text

Abstract:

O conhecimento sobre os mecanismos e a modulação de respostas de estresse em plantas arbóreas é necessário para a exploração sustentável destas importantes fontes de produtos de interesse industrial, também essenciais do ponto de vista ecológico, na regulação do clima e caracterização de diferentes biomas. Nesta tese, foram investigados dois exemplos de estresse em indivíduos jovens de espécies arbóreas, sendo um de uma gimnosperma frente a estresse biótico e outro de uma angiosperma submetida a estresse abiótico: controle da produção de resina por ferimento e moléculas sinalizadoras em Araucaria angustifolia (Bertol.) Kuntzee respostas fisiológicas de um híbrido comercial de eucalipto (Eucalyptus grandis W. Hill X E. urophylla S.T. Blake) à elevação de CO2 e temperatura tendo como fonte de nitrogênio nitrato. No primeiro caso a hipótese testada foi de que a conífera basal A. angustifolia apresentaria controles de regulação distintos de coníferas mais avançadas, como Pinus spp. No segundo caso, a hipótese testada foi de que, sob temperatura ambiente moderada, haveria limitação no uso do excedente de CO2 pelas plantas C3, devido a dificuldades na assimilação de nitrogênio por falta de poder redutor, situação que seria parcialmente compensada por fotorrespiração sob alta temperatura sem restrição hídrica, devido à recuperação da disponibilidade de ácidos orgânicos, poder redutor e consequente assimilação do nitrato. No caso da produção de resina em araucária, a metodologia envolveu basicamente a remoção de acículas (ferimento) e a aplicação de moléculas estimuladoras e sinalizadoras de exsudação de resina conhecidas para Pinus elliottii, espécie mais derivada e de uso comercial, seguida do monitoramento do volume de resina produzido, bem como análise de sua composição por CG-MS. Já para o efeito da elevação de CO2 e temperatura em eucalipto, foram avaliados tratamentos em câmara de crescimento Conviron incluindo condições controle (25 ºC, 379 ppm CO2), elevado CO2 (EC, 730 ppm CO2, 25 ºC), elevada temperatura (ET, 30ºC, 379 ppm CO2) e a combinação destes(EC+ ET, 30ºC, 730 ppm CO2). Monitorou-se parâmetros de crescimento, parâmetros fotossintéticos e de fluorescência da clorofila, bem como o teor de carboidratos, fenólicos, antocianinas, proteínas solúveis e a atividade de nitrato redutase. No que tange à produção de resina em araucária, a hipótese foi refutada, tendo sido verificado que moléculas sinalizadoras típicas para produção de resina em Pinus também foram ativas em araucária, destacando-se etileno, jasmonato e ácido salicílico. Além disso, verificou-se pela primeira vez modulação de produção de resina por nitroprussiato de sódio, um precursor de óxido nítrico. No caso das respostas de eucalipto a simulação de cenários climáticos futuros com fonte oxidada de nitrogênio, os principais resultados foram o melhor desempenho fotossintético e o maior crescimento em plantas sob ET ou EC+ET, parcialmente apoiando a hipótese de que a falta de poder redutor limita o aproveitamento de CO2 por plantas C3 sob condições não condutivas à fotorrespiração, indicando, portanto, a possibilidade de uma resposta compensatória da alta temperatura em relação às dificuldades de assimilação de nitrato, particularmente sob alto CO2 em cenários climáticos futuros. Understanding the mechanisms and the modulation of stress responses in trees is needed for sustainably exploring these important sources of products of commercial interest, which are also essential from an ecological viewpoint, in climate regulation and by characterizing different biomes.In this thesis, two examples of stresses on tree plantlets were investigated, one involving a gymnosperm under biotic stress and the other an angiosperm facing abiotic stress: control of resin production upon wounding and by signaling molecules in Araucaria angustifolia (Bertol.) Kuntze, and physiological responses of a commercial hybrid of eucalypt (Eucalyptus grandis W. Hill X E. urophylla S.T. Blake) having nitrate as sole N source to high CO2 and heat. In the first case, the hypothesis tested was that the basal conifer A. angustifolia would show regulatory controls diverse from those of more advanced conifers, such as Pinus spp. In the second case, it was tested the hypothesis that under moderate temperature there would be a limitation in the use of excess CO2 by C3 plants due to difficulties in assimilating nitrogen as a result of low reducing power, a situation that could be partly compensated by photorespiration under high temperature and no water restriction, because of a recovery of organic acid availability, reducing power, and consequent nitrate assimilation. In the case of araucaria resin, the methodology consisted in removing needles (wounding) and applying stimulatory and/or signaling molecules of resin exudation know to operate in Pinus elliottii, a more derived species used commercially, followed by monitoring the volume of resin yielded, as well as its composition by GC-MS. For the study of the effect of CO2 elevation and high temperature in eucalypt, the treatments evaluated in a Conviron growth chamber were control conditions (25ºC, 379 ppm CO2) elevated CO2 (EC, 730 ppm CO2, 25ºC), elevated temperature (ET, 30ºC, 379 ppm CO2), and combination of these last two conditions (EC+ ET, 30ºC, 730 ppm CO2). Several indicators were monitored, including: growth and photosynthetic parameters, chlorophyll fluorescence, as well as the content of carbohydrates, phenolics, anthocyanins, soluble proteins, and nitrate reductase activity. With regards to the production of resin in araucaria, the hypothesis was rejected, since signaling molecules, typical stimulators of resin in Pinus, were also active in araucaria, particularly ethylene, jasmonate and salicylic acid. Besides, for the first time, it was shown that resin production could be modulated by sodium nitroprussiate, a precursor of nitric oxide. As far as eucalypt responses to simulations of future climate scenarios under a nitrate-only source of nitrogen, the main results were the better photosynthetic performance and growth of plants under ET and EC+ET, partially supporting the hypothesis that the lack of reducing power limits the benefit and effective use of CO2 by C3 plants under conditions not leading to photorespiration. Thereby, this indicates the possibility of a compensatory response of high temperature to overcome the difficulties of nitrate assimilation, particularly under high CO2in future climate scenarios.

APA, Harvard, Vancouver, ISO, and other styles

31

Gatsukovich, Yulia. "Characterization of Eukaryotic Translation Initiation Factor 5A-2 (eIF5A-2) in Arabidopsis thaliana: Effects of Wounding and Pathogen Attack." Thesis, Waterloo, Ont. : University of Waterloo, 2004. http://etd.uwaterloo.ca/etd/ygatsuko2004.pdf.

Full text

Abstract:

Thesis (Ph.D.)--University of Waterloo, 2004. "A thesis presented to the University of Waterloo in fulfillment of the thesis requirement for the degree of Master of Science in Biology." Includes bibliographical references.

APA, Harvard, Vancouver, ISO, and other styles

32

Brendel, Rita Erika [Verfasser], and P. [Akademischer Betreuer] Roesky. "Fear of the dark - How light signalling modulates the herbivore mediated wounding response in rice / Rita Erika Brendel. Betreuer: P. Roesky." Karlsruhe : KIT-Bibliothek, 2015. http://d-nb.info/1067496971/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

La, Fortezza Marco [Verfasser], and Anne-Kathrin [Akademischer Betreuer] Classen. "Stress signaling mediated changes to cell behavior in response to wounding and tumor growth / Marco La Fortezza ; Betreuer: Anne-Kathrin Classen." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2016. http://d-nb.info/1150644060/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Mosblech, Alina [Verfasser], Ingo [Akademischer Betreuer] Heilmann, Andrea [Akademischer Betreuer] Polle, and Gerhard [Akademischer Betreuer] Braus. "Requirement of phosphoinositol-derived signals in the wounding response of Arabidopsis thaliana / Alina Mosblech. Gutachter: Ingo Heilmann ; Andrea Polle ; Gerhard Braus. Betreuer: Ingo Heilmann." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2011. http://d-nb.info/1043068481/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Li, Guanjun [Verfasser], Wilhelm [Gutachter] Boland, and Nicole van [Gutachter] Dam. "Gene regulation in plant herbivory defense : deffect of insect mechanical wounding and chemical oral secretion factors / Guanjun Li ; Gutachter: Wilhelm Boland, Nicole van Dam." Jena : Friedrich-Schiller-Universität Jena, 2017. http://d-nb.info/1177597373/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Quilliam, Richard S. "The role of cell wall invertase activity in source-sink relations in vegetative tissues of Arabidopsis thaliana and in response to wounding and pathogen attack." Thesis, University of Sheffield, 2007. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.752717.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

De, Klerk Theunis Christiaan. "Die boek Prediker as vertrekpunt vir die pastorale begeleiding van die emosioneel verwonde tiener / Theunis Christiaan de Klerk." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4588.

Full text

Abstract:

This study focused on the pastoral guidance of the emotional wounded teen on the basis of a number of broad markers from the book Ecclesiastes. From the basis–theoretical research (Chapters 2 and 3) it was clear that it is a major challenge to come to a proper understanding of the nature and problems of the teen and his experiences.It there is the necessary understanding of all the relevant aspects and if these are handled correctly, it can promote the growth process of the teen developing an intimate relationship with God, and eventually also lead to the experience of a true sense of life and joy. From Ecclesiastes a number of guidelines were identified which can assist in giving the teen the necessary perspective about his daily life struggles. Answers to the search for sense and joy in life do not lie in people and things under the sun, but in a living and intimate relationship with God, in other words in that which is above the sun (to use the imagery of Ecclesiastes). The meta–theoretical section focused on contributions from the adjacent disciplines. Here it was clear that the emotional wounding of the teen results in damage to the forming of identity and self–esteem.When the teen, in a changing environment, does not experience safety and security within healthy relationships, it quite often leads to an identity crisis and to more wounding. From the empirical research it transpired that, as a result of the burden of unresolved emotional baggage from the past, teens are inclined to have a very negative view of the challenges of life and also to experience life as senseless and without joy. In the establishment of an own identity and self–esteem they displayed a strong need for personal relationships. Their negative and weak self–esteem can furthermore be traced to the lack of role models. Another consequence of this lack is a weak relationship with God and other people, as well as an inability to make decisions and to handle crises and trauma. In the practice–theoretical section, through a hermeneutical interaction between basistheoretical guidelines and meta–theoretival perspectives, the formulation of an adapted practice theory, on the basis of guidelines from Ecclesiastes, about the pastoral guidance of the emotional wounded teen was attempted. This model, aimed at pastoral practice, presents parameters for the pastoral guidance of all unresolved trauma and the emotional pain of teens, which are aspects that inhibit spiritual advancement and emotional healing. Only then will the teen be able to truly focus on the enjoyment of life under the sun, in the light of the principles and guidelines from Ecclesiastes. Thesis (Ph.D. (Pastoral))--North-West University, Potchefstroom Campus, 2011.

APA, Harvard, Vancouver, ISO, and other styles

38

Vu, Hieu Sy. "Membrane lipid changes in Arabidopsis thaliana in response to environmental stresses." Diss., Kansas State University, 2014. http://hdl.handle.net/2097/17278.

Full text

Abstract:

Doctor of Philosophy Department of Biology Ruth Welti The molecular mechanisms by which plants respond to environmental stresses to sustain growth and yield have great importance to agriculture. Lipid metabolites are a major element of plant stress responses. The model plant Arabidopsis thaliana is well-suited to study stress-driven compositional dynamics, metabolism, and functions of lipid metabolites. When Arabidopsis plants were subjected to wounding, infection by Pseudomonas syringae pv tomato DC3000 expressing AvrRpt2 (PstAvr), infection by Pseudomonas syringae pv. maculicola (Psm), and low temperature, and 86 oxidized and acylated lipids were analyzed using mass spectrometry, different sets of lipids were found to change in level in response to the various stresses. Analysis of plant species (wheat versus Arabidopsis), ecotypes (Arabidopsis Columbia 0 versus Arabidopsis C24), and stresses (wounding, bacterial infection, and freezing) showed that acylated monogalactosyldiacylglycerol was a major and diverse lipid class that differed in acyl composition among plant species when plants were subjected to different stresses. Mass spectrometry analysis provided evidence that oxophytodienoic acid, an oxidized fatty acid, is significantly more concentrated on the galactosyl ring of monogalactosyldiacylglycerol than on the glycerol backbone. A mass spectrometry method, measuring 272 lipid analytes with high precision in a relatively short time, was developed. Application of the method to plants subjected to wounding and freezing stress in large-scale experiments showed the method produces data suitable for lipid co-occurrence analysis, which identifies groups of lipid analytes produced by identical or inter-twined enzymatic pathways. The mass spectrometry method and lipid co-occurrence analysis were utilized to study the nature of lipid modifications and the roles of lipoxygenases and patatin-like acyl hydrolases in Arabidopsis during cold acclimation, freezing, and thawing.

APA, Harvard, Vancouver, ISO, and other styles

39

Leandersson, Dennis. "The role of copulatory wound infliction on fitness in Drosophila melanogaster." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-84494.

Full text

Abstract:

One of the more fascinating Darwinian puzzles in sexual selection is that of copulatory wounding. For those taxa displaying this behavior, and that does not engage in traumatic insemination, the function of wound infliction during copulation remains unknown. In this study, the intention was to evaluate the purpose of copulatory wounding in Drosophila melanogaster and the consequences it might have for male and female fecundity. The present study measured the size and number of wounds that males from different stocks of Darwinian fitness imposed on females, as well as the copulation duration and the resulting fecundity. The number of wounds and the total wound size showed no apparent correlation to fecundity, but a significant difference in variation of the number of wounds inflicted on females was observed between males from two different lines of fitness. Wounded females were also considerably more common than non-wounded females, as were wounds that were paired compared to non-paired copulatory wounds. The results suggests that wounding might be an adaptive male trait and a copulatory courtship interpretable to females, implying a possible case of cryptic female choice. Since most wounds were paired, this implies that a bilaterally symmetrical organ is causing these wounds. Also, wounding was not as important for fecundity as previously thought. Ett av de mer fascinerande Darwinistiska pusslen inom sexuell selektion är skadande under kopulationen. För de taxa som uppvisar detta beteende, och inte engagerar sig i traumatisk insemination, så är funktionen av kopulationsskador okänd. I denna studie så var avsikten att utvärdera syftet av kopulationsskador hos Drosophila melanogaster och de konsekvenser beteendet kan ha för det resulterande antalet avkomma. Denna studie uppmätte storleken och antalet skador som hanar av olika Darwinistisk fitness vållade honor, samt kopulationstiden och antalet avkomma. Antalet skador och den totala storleken av skador visade ingen signifikant korrelation till antalet avkommor, däremot uppvisades signifikanta variationsskillnader mellan hanar av två olika fitnessnivåer. Skadade honor visade sig också vara betydligt vanligare än icke skadade honor och parade skador var även vanligare än icke parade skador. Resultaten indikerade att kopulationsskador kan vara en adaptiv egenskap hos hanar och en form av uppvaktning som honorna kan tyda, vilket kan antyda ett möjligt fall av ”kryptiskt honligt val”. Eftersom de flesta skador var parade, så antyder detta att ett bilateralt symmetriskt organ orsakar skadorna. Kopulationsskador visade sig heller inte vara så viktiga som man tidigare antagit.

APA, Harvard, Vancouver, ISO, and other styles

40

Heyerdahl, Emily K., and Steven J. McKay. "Condition Of Live Fire-Scarred Ponderosa Pine Eleven Years After Removing Partial Cross-Sections." Tree-Ring Society, 2008. http://hdl.handle.net/10150/622566.

Full text

Abstract:

Our objective is to report mortality rates for ponderosa pine trees in Oregon ten to eleven years after removing a fire-scarred partial cross-section from them, and five years after an initial survey of post-sampling mortality. We surveyed 138 live trees from which we removed fire-scarred partial crosssections in 1994/95 and 387 similarly sized, unsampled neighbor trees of the same species. These trees were from 78 plots distributed over about 5,000 ha at two sites in northeastern Oregon. The annual mortality rate for sectioned trees from 1994/95 to 2005 was 3.6% compared to 2.1% for the neighbor trees. However, many of the trees that died between 2000 and 2005 were likely killed by two prescribed fires at one of the sites. Excluding all trees in the plots burned by these fires (regardless of whether they died or not), the annual mortality rate for sectioned trees was 1.4% (identical to the rate from 1994/95 to 2000) compared to 1.0% for neighbor trees. During these fires, a greater proportion of sectioned trees died than did catfaced neighbor trees (80% versus 64%) but the difference was not significant.

APA, Harvard, Vancouver, ISO, and other styles

41

Duan, Cuifang. "Etude de l'interaction entre l'éthylène et le jasmonate, hormones impliquées dans la production de caoutchouc naturel chez Hevea brasiliensis." Thesis, Montpellier, SupAgro, 2011. http://www.theses.fr/2011NSAM0032/document.

Full text

Abstract:

Les jasmonates et l'éthylène sont d'importants signaux de régulation du développement des plantes et de réponse aux stress biotiques et abiotiques. La production de jasmonates est induite à la suite d'une blessure mécanique ou des agents pathogènes. L'acide jasmonique et l'éthylène agissent en synergie sur l'activation de l'expression des gènes de défense tels que PDF1.2. Le Facteur de Réponse à l'Ethylène 1 (ERF1) est un intégrateur clé de ces signaux hormonaux chez Arabidopsis. ERF1 appartient à la superfamille des facteurs de transcription AP2/ERF, lesquels jouent un rôle crucial dans le développement et la réponse aux stress. Hevea brasiliensis est la seule source commerciale de caoutchouc naturel, lequel est synthétisé dans les cellules laticifères. Le latex s'écoule du tronc des hévéas après la saignée. L'éthéphon, un générateur d'éthylène, est un stimulant exogène adopté largement dans les plantations d'hévéa pour améliorer la production de latex en prolongeant l'écoulement de latex et en stimulant le métabolisme des cellules requis pour la régénération du latex. Les jasmonates sont aussi impliqués dans la formation des laticifères. Etant donné l'implication de l'éthylène et de l'acide jasmonique dans la réponse coordonnée à la saignée et à la stimulation par l'éthéphon chez Hevea brasiliensis, leur interaction est supposée jouer un rôle important dans la production de latex.L'objectif de cette thèse est de découvrir les régulateurs clés de l'interaction entre la blessure, le jasmonate et l'éthylène chez Hevea brasiliensis. A travers l'analyse de l'expression de 25 gènes impliqués dans les voies de transduction du jasmonate, de l'éthylène et dans le métabolisme cellulaire, nous avons montré que des voies de réponse dépendantes et indépendantes à l'éthylène et au jasmonate coexistent chez Hevea brasiliensis. La régulation temporelle influence aussi l'expression des gènes. L'étude s'est alors focalisée sur les facteurs de transcription de la superfamille des AP2/ERF. A partir de bases de données de séquences transcriptomiques de différents tissus obtenu par pyroséquençage, 173 membres AP2/ERF ont été identifiés chez Hevea brasiliensis. Cette superfamille est divisée en 3 familles majeures : AP2, ERF et RAV. Soixante six membres sont exprimés dans le latex ce qui suggère qu'ils ont une fonction importante dans le métabolisme des laticifères. En plus du microARN 172 connu pour cibler les transcrits AP2/ERF, six autres microARNs ont été prédits pour inhiber les transcrits de cette superfamille. L'identification de l'orthologue à AtERF1 a été aussi menée chez Hevea brasiliensis. L'expression de 14 gènes HbERF du groupe IX a été étudiée en réponse à la blessure, au méthyl jasmonate et à l'éthylène. L'accumulation relative des transcrits est remarquable pour trois gènes : HbERF-IXc4, HbERF-IXc5 et HbERF-IXc6. Ces gènes candidats ont été caractérisés pour la localisation subcellulaire et la trans-activation du promoteur du gène PDF1.2. La fusion traductionnelle HbERF-IXc4::GFP a révélé que HbERF-IXc4 code pour une protéine nucléaire comme les facteurs de transcription. Le HbERF-IXc5 induit la plus forte activation du promoteur du gene PDF1.2 qui est un gène de défense induit fortement par AtERF1 et ORA59. Ces résultats suggèrent que HbERF-IXc5 est l'orthologue à AtERF1 chez Hevea brasiliensis, lequel est impliqué dans la communication des voies de signalisation de l'éthylène et du jasmonate. L'identification des transcrits AP2/ERF chez Hevea brasiliensis, et la caractérisation des ERFs du groupe IX apportent les bases générales pour étudier la régulation moléculaire de la production de latex en réponse aux stress et de la différentiation des cellules laticifères. Nos résultats suggèrent que HbERF-IXc5 est un intégrateur essentiel des voies de signalisation éthylène et jasmonate chez Hevea brasiliensis Jasmonates and ethylene are important signals in regulating the plant development and metabolism, and in response to biotic and abiotic stresses. Production of jasmonates is induced by mechanical wounding and pathogens. Jasmonic acid and ethylene are synergistically required to activate the expression of some defence related genes such as PDF1.2. Ethylene Response Factor 1 (ERF1) was demonstrated as a key integrator in the signal interaction in Arabidopsis. ERF1 belongs to AP2/ERF transcription factors superfamily, which plays a crucial role in plant development and response to biotic and abiotic stresses. Hevea brasiliensis is the sole source of natural rubber, which is synthesized in latex cells. Latex is expelled out after tapping the soft bark. Ethephon, an ethylene releaser, is an exogenous stimulant adopted widely in the rubber plantation for improving latex yield by prolonging latex flow and by stimulating the metabolism required for the latex regeneration. Jasmonates are also involved in the laticifer formation. Given the involvement of ethylene and jasmonic acid in the coordinated response to tapping and ethephon stimulation in Hevea brasiliensis, their interaction is considered to play an important role in latex production. The objective of this thesis is aiming to discover the key regulators in the interaction of wounding, jasmonate and ethylene in Hevea brasiliensis. Through the expression analysis on one group of 25 genes involved in the jasmonate and ethylene and cellular metabolism, we discovered that jasmonate and ethylene dependent and independent response coexist in Hevea brasiliensis. Temporal regulation can also have an influence on the gene expression. We then focused the study on the AP2/ERF transcription factor superfamily. Based on new generation of sequencing data, we identified 173 AP2/ERF members from several Hevea brasiliensis transcripts libraries. This superfamily is divided into 3 major families: AP2, ERF and RAV. Sixty six members are expressed in latex which may indicate that they have an important function in the latex metabolism. In addition to the microRNA 172, which is known to target AP2/ERF transcripts, six other microRNAs were predicted to inhibit transcripts of this superfamily. The identification of the AtERF1 orthologous gene was further conducted in Hevea brasiliensis. Expression analysis of 14 HbERF genes from the group IX was studied in response to wounding, methyl jasmonate and ethylene. A remarkable relative transcript accumulation was observed for genes HbERF-IXc4, HbERF-IXc5 and HbERF-IXc6. These candidate genes were further analysed for subcellular localization and trans-activation of the promoter of the PDF1.2 gene. The translational fusion HbERF-IXc4::GFP revealed that HbERF-IXc4 encoded a nuclear targeted protein like transcription factor. The HbERF-IXc5 was shown to mediate the activation of the PDF1.2 promoter, which is a defence gene dramatically induced by AtERF1 and ORA59. For that reason, HbERF-IXc5 is suggested to be AtERF1 ortholog gene in Hevea brasiliensis, which is at the crosstalk of jasmonic acid and ethylene signalling pathways. This identification of the Hevea brasiliensis AP2/ERF transcripts and the characterization of the ERF group IX provide general basis for studying the molecular regulation of both latex production in response to abiotic stresses and differentiation of latex cells. Our results suggested that the HbERF-IXc5 is an essential integrator of the jasmonic acid and ethylene signalling pathways in Hevea

APA, Harvard, Vancouver, ISO, and other styles

42

Karsch, Susanne [Verfasser], Andreas [Akademischer Betreuer] Janshoff, Andreas [Gutachter] Janshoff, Jörg [Gutachter] Großhans, Sarah [Gutachter] Köster, Florian [Gutachter] Rehfeldt, Silvio [Gutachter] Rizzoli, and Thomas [Gutachter] Burg. "Collective Mechanical Behavior of Epithelial Cells - The Impact of Micro-Wounding / Susanne Karsch ; Gutachter: Andreas Janshoff, Jörg Großhans, Sarah Köster, Florian Rehfeldt, Silvio Rizzoli, Thomas Burg ; Betreuer: Andreas Janshoff." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://d-nb.info/1189419521/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Chen, Peiwen. "Role of collagen VI in peripheral nerves and wound-induced hair regrowth." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424094.

Full text

Abstract:

Collagen VI is an extracellular matrix (ECM) molecule dynamically expressed in a variety of tissues, including peripheral nerves and skin. However, the role of collagen VI in the peripheral nervous system (PNS) and hair follicle growth is yet unknown. The main focus of my PhD study was to investigate the role and the underlying mechanisms of collagen VI in peripheral nerve myelination and function, in PNS regeneration, as well as in wound-induced hair growth. During the first year of my PhD, I focused on investigating the phenotype of peripheral nerve myelination and function in collagen VI null (Col6a1–/–) mice. The data shows that Schwann cells, but not axons, contribute to collagen VI deposition in peripheral nerves. Lack of collagen VI in Col6a1–/– mice leads to hypermyelination via multiple signaling pathways, disorganized C-fibers in the PNS, impaired nerve conduction velocity, and sensorimotor dysfunction. These findings indicate that that collagen VI is a critical component of PNS contributing to the structural integrity and proper function of peripheral nerves. The second part of my PhD work focused on investigating the role of collagen VI in PNS under pathological conditions using nerve crush injury models, and revealed a novel mechanism of this ECM protein in modulating macrophage function. The results show that collagen VI is critical for macrophage migration and polarization during peripheral nerve regeneration. Nerve injury induces a robust upregulation of collagen VI, whereas lack of collagen VI in Col6a1–/– mice delays peripheral nerve regeneration. In vitro studies demonstrated that collagen VI promotes macrophage migration and polarization via AKT and PKA pathways. Col6a1–/– macrophages exhibit impaired migration abilities and reduced anti-inflammatory (M2) phenotype polarization, but are prone to skewing towards pro-inflammatory (M1) phenotype. In vivo, macrophage recruitment and M2 polarization are impaired in Col6a1–/– mice after nerve injury. The delayed nerve regeneration of Col6a1–/– mice is induced by macrophage deficits and rejuvenated by transplantation of wild-type bone marrow cells. These results identify collagen VI as a novel regulator for peripheral nerve regeneration by modulating macrophage function. In the last year of my PhD I moved my focus to skin homeostasis and investigated the role of collagen VI in wound-induced hair regrowth. The data shows that collagen VI is strongly deposited in hair follicles, and it is dramatically upregulated by skin wounding. Lack of collagen VI in Col6a1–/– mice promotes wound-induced hair regrowth, but does not affect skin regeneration. Conversely, addition of purified collagen VI rescues the abnormal wound-induced hair regrowth in Col6a1–/– mice. Mechanistic studies revealed that the increased wound-induced hair regrowth of Col6a1–/– mice is triggered by upregulation of Keratin 79 and activation of the Wnt/beta-catenin signaling pathway, and is abolished by inhibition of the Wnt/beta-catenin pathway. These findings highlight the essential relationships between ECM and hair follicle regeneration, and point at collagen VI as a potential therapeutic target for hair loss. Altogether, the data I obtained during my PhD studies strongly support a key role of collagen VI in peripheral nerves and wound-induced hair follicle growth, thus paving the way for future studies on ECM molecules in PNS and skin under physiological and pathological conditions. Il collagene VI è una proteina della matrice extracellulare (MEC), espressa in un’ampia varietà di tessuti, inclusi i nervi periferici e la pelle. La funzione del collagene VI nel sistema nervoso periferico (SNP) e nel follicolo pilifero rimane tuttavia ancora sconosciuta. L'obiettivo principale del mio studio di dottorato è stato quindi, quello di indagare il ruolo del collagene VI nella mielinizzazione dei nervi periferici ed i meccanismi molecolari con cui ne regola la funzione e la rigenerazione in seguito a danno, così come nella rigenerazione pilifera indotta da ferita. Durante il primo anno di dottorato, mi sono concentrato sullo studio del processo di mielinizzazione e sulla funzione dei nervi periferici in topi Col6a1–/–, privi di collagene VI. I dati dimostrano che le cellule di Schwann, ma non il comparto neuronale, contribuiscono alla deposizione del collagene VI nei nervi periferici. In assenza della proteina, si osservano ipermielinizzazione, causata dalla dis-regolazione di diversi meccanismi di segnalazione molecolare, disorganizzazione delle fibre di tipo C, deficits nella velocità di conduzione nervosa e nelle funzioni sensoriali e motorie. Questi risultati indicano che il collagene VI è un componente critico nel SNP, che contribuisce alla integrità strutturale e al corretto funzionamento dei nervi periferici. La seconda parte del mio lavoro di dottorato è incentrata sullo studio del ruolo del collagene VI nel SNP in condizioni patologiche, sfruttando un modello di lesione nervosa. Ciò ha rivelato un nuovo ruolo di questa proteina della MEC nel modulare la funzione dei macrofagi. I risultati mostrano che il collagene VI è fondamentale per la migrazione e la polarizzazione dei macrofagi durante la rigenerazione dei nervi periferici. La lesione del nervo induce una notevole over-espressione del collagene VI, mentre in assenza della proteina, nei topi Col6a1–/– si osserva un ritardo nella rigenerazione. Studi in vitro hanno dimostrato che il collagene VI promuove la migrazione e la polarizzazione dei macrofagi per mezzo di AKT e PKA. Macrofagi derivati da topi Col6a1–/– presentano ridotte capacità di migrazione e di polarizzazione verso il fenotipo anti-infiammatorio (M2), mentre risultano inclini al fenotipo pro-infiammatorio (M1). Anche in vivo, il reclutamento dei macrofagi e la polarizzazione in senso M2 appaiono compromesse in topi Col6a1–/– post-lesione. La rigenerazione dei nervi periferici è ritardata nei topi Col6a1–/–, a causa dei deficit a carico dei macrofagi, ma è recuperata in seguito a trapianto di cellule wild-type del midollo osseo. Questi risultati identificano il collagene VI come componente fondamentale nella regolazione della rigenerazione del nervo periferico modulando la funzione dei macrofagi. Nell'ultimo anno del mio dottorato la mia attenzione si è focalizzata sull’omostasi della pelle, studiando il ruolo del collagene VI nella ricrescita del pelo in seguito a lesione. I dati mostrano che il collagene VI è depositato ampiamente nei follicoli piliferi, ed è drammaticamente up-regolato in seguito a lesione della pelle. In assenza di collagene VI, in topi Col6a1–/–, la ricrescita del pelo appare favorita in seguito a lesione, senza che vi sia alcuna influenza sulla rigenerazione della pelle. Inoltre l’iniezione in loco di collagene VI purificato, riduce l’anomala ricrescita del pelo post-lesione in topi Col6a1–/–. Studi meccanicistici hanno rivelato che l'aumento della ricrescita del pelo in assenza di collagene VI è innescato dall’up-regolazione della cheratina-79 e dall'attivazione della via di segnalazione di Wnt/beta-catenina, e l’inibizione esercitata dal collagne VI purificato, agisce sulla stessa via Wnt/beta-catenina. Questi risultati evidenziano il rapporto essenziale tra la MEC e la rigenerazione del follicolo pilifero, e puntano al collagene VI come un potenziale bersaglio terapeutico per la perdita dei capelli. Complessivamente, i dati che ho ottenuto durante gli studi di dottorato sostengono con forza un ruolo chiave del collagene VI nei nervi periferici e nella rigenerazione del follicolo pilifero in seguito a lesione, aprendo così la strada a futuri studi su altri componenti della MEC nel SNP e nella pelle in condizioni fisiologiche e patologiche.

APA, Harvard, Vancouver, ISO, and other styles

44

Lewis, Christopher John. "The role of bone morphogenetic protein signalling in the control of skin repair after wounding : cellular and molecular mechanisms of cutaneous wound healing mediated by bone morphogenetic proteins and their antagonist Noggin." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/7337.

Full text

Abstract:

Bone morphogenetic proteins (BMPs) and their receptors (BMPRs) coordinate tissue development and postnatal remodelling by regulating proliferation, differentiation and apoptosis. However, their role in wound healing remains unclear. To study this, transgenic mice overexpressing Smad1 (K14-caSmad1) or the BMP antagonist Noggin (K14-Noggin) were utilised, together with human and mouse ex vivo wound healing models and in vitro keratinocyte culture. In wild-type mice, transcripts for Bmpr-1A, Bmpr-II, Bmp ligands and Smad proteins were decreased following tissue injury, whilst Bmpr-1B expression was up-regulated. Furthermore, immunohistochemistry revealed a down-regulation of BMPR-1A in hair follicles adjacent to the wound in murine skin, whilst in murine and human wounds, BMPR-1B and phospho-Smad-1/5/8 expression was pronounced in the wound epithelial tongue. K14-caSmad1 mice displayed retarded wound healing, associated with reduced keratinocyte proliferation and increased apoptosis, whilst K14-Noggin mice exhibited accelerated wound healing. Furthermore, microarray analysis of K14-caSmad1 epidermis revealed decreased expression of distinct cytoskeletal and cell motility-associated genes including wound-associated keratins (Krt16, Krt17) and Myo5a versus controls. Human and mouse keratinocyte proliferation and migration were suppressed by BMP-4/7 both in vitro and ex vivo, whilst they were stimulated by Noggin. Additionally, K14-caSmad1 keratinocytes showed retarded migration compared to controls when studied in vitro. Furthermore, Bmpr-1B silencing accelerated migration and was associated with increased expression of Krt16, Krt17 and Myo5a versus controls. Thus, this study demonstrates that BMPs inhibit proliferation, migration and cytoskeletal re-organization in epidermal keratinocytes during wound healing, and raises a possibility that BMP antagonists may be used for the future management of chronic wounds.

APA, Harvard, Vancouver, ISO, and other styles

45

Lewis, Christopher J. "The role of bone morphogenetic protein signalling in the control of skin repair after wounding. Cellular and molecular mechanisms of cutaneous wound healing mediated by bone morphogenetic proteins and their antagonist Noggin." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/7337.

Full text

Abstract:

Bone morphogenetic proteins (BMPs) and their receptors (BMPRs) coordinate tissue development and postnatal remodelling by regulating proliferation, differentiation and apoptosis. However, their role in wound healing remains unclear. To study this, transgenic mice overexpressing Smad1 (K14-caSmad1) or the BMP antagonist Noggin (K14-Noggin) were utilised, together with human and mouse ex vivo wound healing models and in vitro keratinocyte culture. In wild-type mice, transcripts for Bmpr-1A, Bmpr-II, Bmp ligands and Smad proteins were decreased following tissue injury, whilst Bmpr-1B expression was up-regulated. Furthermore, immunohistochemistry revealed a down-regulation of BMPR-1A in hair follicles adjacent to the wound in murine skin, whilst in murine and human wounds, BMPR-1B and phospho-Smad-1/5/8 expression was pronounced in the wound epithelial tongue. K14-caSmad1 mice displayed retarded wound healing, associated with reduced keratinocyte proliferation and increased apoptosis, whilst K14-Noggin mice exhibited accelerated wound healing. Furthermore, microarray analysis of K14-caSmad1 epidermis revealed decreased expression of distinct cytoskeletal and cell motility-associated genes including wound-associated keratins (Krt16, Krt17) and Myo5a versus controls. Human and mouse keratinocyte proliferation and migration were suppressed by BMP-4/7 both in vitro and ex vivo, whilst they were stimulated by Noggin. Additionally, K14-caSmad1 keratinocytes showed retarded migration compared to controls when studied in vitro. Furthermore, Bmpr-1B silencing accelerated migration and was associated with increased expression of Krt16, Krt17 and Myo5a versus controls. Thus, this study demonstrates that BMPs inhibit proliferation, migration and cytoskeletal re-organization in epidermal keratinocytes during wound healing, and raises a possibility that BMP antagonists may be used for the future management of chronic wounds.

APA, Harvard, Vancouver, ISO, and other styles

46

Mendes, Teresa Drummond Correia. "Efeito do dano físico sobre o metabolismo de folhas de taioba, Xanthosoma sagittifolium (L.) Schott." Universidade Federal de Viçosa, 2009. http://locus.ufv.br/handle/123456789/4303.

Full text

Abstract:

Made available in DSpace on 2015-03-26T13:36:38Z (GMT). No. of bitstreams: 1 texto completo.pdf: 399295 bytes, checksum: 3f7a6b3857d3216713ce9233ed752433 (MD5) Previous issue date: 2009-02-18 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Vegetables like leaves of tannia are subject to various factors which cause deterioration. Among these factors, mechanical damage triggers a series of physiological responses that occur at the site of the injury and surrounding tissues. The objective of this study was to evaluate the physiological responses of tannia leaves mechanical damaging, and whether these responses can be transmitted to tissues surrounding the site of injury. For this, the leaves were harvested and mechanical injuries were inflicted by using a needle. To verify that the changes resulting from injury extending to the region adjacent to the site of the damage were drilling, forming concentric circles of 3 diameters: 0.6 cm, circle A, located the needle injured area and 1.1 (B ) and 1.6 (C) cm around the circle, forming concentric rings. As control, was used the undamaged region from the leaf lamina. After 2, 4 and 6 hours of damaging, the discs were removed for the analysis of ethylene and CO2 production. The samples were also used for the assessment of weight loss, accumulation of soluble phenolic compounds, activity of phenylalanine ammonia lyase (PAL), total soluble sugars, non-reducing and reducing sugars, and starch after 30 minutes, 2, 4 and 6 hours of injury. Chlorophyll content was also determined after 30 minutes, 24, 48 and 72 hours. Intact and damaged discs were unfiltered with ACC to evaluate the activity of ACC oxidase and production of CO2, measured after 2, 4 and 6 hours of the tissue being damaged. The injury stimulated ethylene production by 39% in the disc B and 41% in CO2 production in the disc A, 6 hours after inflicting the damage. The experiment showed that addition of ACC induced an increase of 62% in ethylene production 4 hours after the injury and an increase of 40% in CO2 production in damaged discs. But, in the absence of ACC respiration was increased up to 4- fold in the injury discs. As the percentage of fresh matter, the injured discs showed lower percentage of mass compared to controls, from 2 hours after the damage, until the end of the experiment, and the reduction was more intense in the circle A; however, there was not a consistent reduction in the level of chlorophyll induced by the damage. The accumulation of phenols was stimulated after 4 and 6 hours after the treatment, especially in the damaged disc A, which showed 44 and 50% more soluble phenolic compounds compared to control discs, respectively at 4 and 6 hours. There was increase in the activity of PAL in the damaged disc A in all the analyzed times. The content of total soluble sugars, non-reducing sugar and starch were higher in damaged discs throughout the experiment. The levels of reducing sugars were higher in the damaged discs, allowing to suggest that occurred higher consumption of reserves at the site of injury, where the respiratory rate was also higher, however, this consumption was not sufficient to cause a depletion of carbohydrates in the damaged discs. Produtos hortícolas, como a taioba, estão sujeitos a vários fatores que causam a deterioração. Dentre esses fatores, o dano mecânico desencadeia uma série de respostas fisiológicas que podem ocorrer no sítio da injúria e nos tecidos adjacentes. O objetivo deste trabalho foi avaliar as respostas fisiológicas em folhas de taioba danificadas, e se essas respostas podem ser transmitidas aos tecidos próximos do local da injúria. Para isto, folhas de taioba foram colhidas e injúrias físicas foram provocadas com o uso de uma agulha. Para verificar se as alterações resultantes da injúria se estendiam para a região vizinha ao local do dano foram feitas perfurações, formando círculos concêntricos de 3 diâmetros: 0,6 cm, círculo A, onde se localizavam os furos de agulha e 1,1 (B) e 1,6 (C) cm em torno do círculo A, formando anéis concêntricos. Como controle foi utilizada a região não danificada da folha. Após 2, 4 e 6 horas da realização do dano foram retiradas amostras para análise da produção de etileno e CO2. Amostras para avaliação da porcentagem de massa de matéria fresca, acúmulo de compostos fenólicos solúveis, atividade da enzima fenilalanina amônia liase (PAL), açúcares solúveis totais, não redutores, redutores e amido foram retiradas após 30 minutos, 2, 4 e 6 horas da imposição dos tratamentos; e o teor de clorofila foi verificado após 30 minutos, 24, 48 e 72 horas. Discos intactos e injuriados mecanicamente foram embebidos com ACC para análise da atividade da enzima ACC oxidase e da produção de CO2. Amostras foram retiradas após 2, 4 e 6 horas da realização do dano. O dano estimulou a produção de etileno em 39% no disco B e em 41% a produção de CO2 no disco A, 6 horas após a realização da injúria. No experimento com ACC após 4 horas, o dano induziu aumento de 62% na produção de etileno e de 40% na respiração. Porém, na ausência de ACC, houve estímulo da respiração de até 4 vezes nos discos injuriados. Quanto à porcentagem de massa de matéria fresca, constatamos que os discos injuriados, a partir de 2 horas, apresentaram menores porcentagens de massa comparados aos controles e que esta redução foi mais intensa no círculo A, entretanto, não houve uma consistente redução no teor de clorofila devido ao dano. Após 4 e 6 horas da realização do dano, ocorre estímulo ao acúmulo de fenóis, principalmente no disco A danificado, que apresentou 44 e 50% mais compostos fenólicos solúveis que o controle, respectivamente. Também se verificou maior atividade da PAL no disco A danificado, em todas as horas analisadas. O teor de açúcares solúveis totais, não redutores e amido foram maiores nos discos danificados durante todo o experimento. Já os teores de açúcares redutores foram maiores no disco A danificado, nos permitindo sugerir que há consumo de reservas no local da injúria, onde a taxa respiratória também foi maior, entretanto, esse consumo não é suficiente para se verificar esgotamento de carboidratos nos discos danificados.

APA, Harvard, Vancouver, ISO, and other styles

47

Nguyen, Trang Hieu. "Analysis of wound-induced jasmonate biosynthesis and signaling in defense and root development responses in rice." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTG034.

Full text

Abstract:

Le riz est la première céréale consommée dans l’alimentation avec plus de 600 millions de tonnes produites chaque année. Ainsi les contraintes d’ordre biotique et abiotique exercées sur cette céréale peuvent être particulièrement préjudiciables a la sécurité alimentaire. Des interactions moléculaires complexes orchestrant le développement des plantes et les mécanismes de défense face a des agents pathogènes ou a des contraintes climatiques jouent un rôle majeur dans l’adaptation des plantes. Récemment, il a été mis en évidence le rôle crucial joue par les hormones de défense tel que le jasmonate dans la modulation des réponses permettant aux plantes de s’adapter a leur environnement. Ainsi, le décryptage de la signalisation et des réponses au jasmonate présentent un intérêt majeur chez les céréales. Dans ce cadre, ces travaux de thèse ont permis d’analyser le rôle de cette phytohormone dans les réponses de défense locales et distales suite à un stress mécanique. De plus, par des approches fonctionnelles, un nouveau rôle du jasmonate a été mis en évidence dans le contrôle systémique du développement des racines coronaires sous stress chez le riz. La compréhension des mécanismes de réponse à la blessure et l’impact sur le développement, notamment au niveau de la partie « cachée » de la plante, le système racinaire, permet d'envisager la création de nouvelles variétés et l’optimisation de méthodes de culture du riz Rice is the first cereal consumed by human with more than 600 million tons produced each year. Thus the biotic and abiotic constraints on this cereal can be particularly damaging to food security. Complex molecular interactions orchestrating plant development and defense mechanisms against pathogens or climatic constraints play a major role in plant adaptation. Recently, it has been highlighted the crucial role played by defense hormones such as jasmonate in modulating responses allowing plants to adapt to their environment. Thus, the analysis of signaling and responses to jasmonate are of major interest for cereals. In this context, this thesis work allowed to analyze the role of this phytohormone in local and distal defense responses following mechanical stress. In addition, by functional approaches, a new role of jasmonate has been demonstrated in the systemic control of stress-induced coronary root development in rice. The understanding of the mechanisms of response to injury and the impact on development, especially at the level of the "hidden" part of the plant, the root system, makes it possible to consider the creation of new varieties and the optimization of breeding methods and rice cultivation

APA, Harvard, Vancouver, ISO, and other styles

48

Yamoah, Emmanuel. "A model system using insects to vector Fusarium tumidum for biological control of gorse (Ulex europaeus)." Phd thesis, Lincoln University. Bio-Protection and Ecology Division, 2007. http://theses.lincoln.ac.nz/public/adt-NZLIU20080131.114607/.

Full text

Abstract:

The overall objective of this study was to test the hypothesis that insects can vector F. tumidum conidia to infect gorse plants with the aim of developing an alternative approach to mycoherbicide delivery to control weeds. Four potential insect species (Apion ulicis, Cydia ulicetana, Epiphyas postvittana and Sericothrips staphylinus) were assessed for their ability to vector F. tumidum conidia. To achieve this, the external microflora (bacteria and fungi) and the size and location of fungal spores on the cuticle of these insect species were determined. In addition, the ability of the insects to pick up and deposit F. tumidum conidia on agar was studied. Based on the results from these experiments, E. postvittana was selected for more detailed experiments to determine transmission of F. tumidum to infect potted gorse plants. The factors promoting pathogenicity of F. tumidum against gorse and the pathogen loading required to infect and kill the weed were also determined. The external microflora of the four insect species were recovered by washing and plating techniques and identified by morphology and polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and sequencing of internally transcribed spacer (ITS) and 16S rDNA. A culture-independent technique (direct PCR) was also used to assess fungal diversity by direct amplification of ITS sequences from the washings of the insects. All insect species carried Alternaria, Cladosporium, Nectria, Penicillium, Phoma, Pseudozyma spp. and entomopathogens. Ninety four per cent of the 178 cloned amplicons had ITS sequences similarity to Nectria mauritiicola. E. postvittana carried the largest fungal spores (mean surface area of 125.9 ìm2) and the most fungal CFU/insect. About 70% of the fungi isolated from the insects were also present on the host plant (gorse) and the understorey grass. The mean size of fungal spores recovered from the insect species correlated strongly with their body length (R² = 85%). Methylobacterium aquaticum and Pseudomonas lutea were common on all four insect species. Pseudomonas fluorescens was the most abundant bacterial species. In the pathogenicity trials, the effectiveness of F. tumidum in reducing root and shoot biomass of 16 and 8 wk old gorse plants was significantly increased with wounding of the plants. Older plants (32 wk old) which were wounded and inoculated were significantly shorter, more infected and developed more tip dieback (80%) than plants which were not wounded (32%). This indicates that damage caused by phytophagous insect species present on gorse through feeding and oviposition may enhance infection by F. tumidum. Wounding may release nutrients (e.g. Mg and Zn) essential for conidia germination and germ tube elongation and also provide easier access for germ tube penetration. Conidial germination and germ tube length were increased by 50 and 877%, respectively when incubated in 0.2% of gorse extract solution for 24 h compared with incubation in water. Inoculum suspensions amended with 0.2% of gorse extract caused more infection and significantly reduced biomass production of 24 wk old gorse plants than suspensions without gorse extract. A minimum number of about 900 viable conidia/infection site of F. tumidum were required to infect gorse leaves. However, incorporation of amendments (which can injure the leaf cuticle) or provision of nutrients (i.e. gorse extract or glucose) in the formulation might decrease the number of conidia required for lesion formation. Scanning electron micrographs showed that germ tube penetration of gorse tissue was limited to open stomata which partly explain the large number of conidia required for infection. The flowers and leaves were more susceptible to F. tumidum infection than the spines, stems and pods. An experiment to determine the number of infection sites required to cause plant mortality showed that the entire plant needs to be inoculated in order for the pathogen to kill 10 wk old plants as F. tumidum is a non systemic pathogen. The number of infection sites correlated strongly with disease severity (R² = 99.3%). At least 50% of the plant was required to be inoculated to cause a significant reduction in shoot dry weight. F. tumidum, applied as soil inoculant using inoculated wheat grains in three separate experiments, significantly suppressed gorse seedling emergence and biomass production. In experiments to determine the loading capacity of the insect species, E. postvittana, the largest insect species studied, carried significantly more (68) and deposited significantly more (29) F. tumidum conidia than the other species. Each E. postvittana, loaded with 5,000 conidia of F. tumidum, transmitted approximately 310 conidia onto gorse plants but this did not cause any infection or affect plant growth as determined by shoot fresh weight and shoot height. E. postvittana on its own did not cause any significant damage to gorse and did not enhance F. tumidum infection. It also failed to spread the pathogen from infected plants to the healthy ones. There was no evidence of synergism between the two agents and damage caused by the combination of both E. postvittana and F. tumidum was equivalent to that caused by F. tumidum alone. This study has shown that E. postvittana has the greatest capacity to vector F. tumidum since it naturally carried the largest and the most fungal spores (429 CFU/insect). Moreover, it naturally carried Fusarium spp. such as F. lateritium, F. tricinctum and Gibberella pulicaris (anamorph Fusarium sambucinum) and was capable of carrying and depositing most F. tumidum conidia on agar. Coupled with the availability of pheromone for attracting the male insects, E. postvittana may be a suitable insect vector for delivering F. tumidum conidia on gorse using this novel biocontrol strategy. Although it is a polyphagous insect, and may visit non-target plants, F. tumidum is a very specific pathogen of gorse, broom and a few closely related plant species. Hence, using this insect species to vector F. tumidum in a biological control programme, should not pose a significant threat to plants of economic importance. However, successful control of gorse using this "lure-load-infect" concept would depend, to a large extent on the virulence of the pathogen as insects, due to the large size of F. tumidum macroconidia, can carry only a small number of it.

APA, Harvard, Vancouver, ISO, and other styles

49

Gkatza, Nikoletta A. "RNA modifications and processing in cell homeostasis and in response to oxidative stress." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/277276.

Full text

Abstract:

RNA modifications and processing events are important modulators of global gene expression. Genomic mutations in the RNA methylase NSun2 and the alternative splicing factor Srsf2 are linked to neurological disorders and cancer in humans, respectively. NSun2 methylates cytosine-5 in most tRNAs and, to a lesser extent, other ncRNAs and mRNAs. Srsf2 is a critical component of the spliceosome and interacts with abundant ncRNAs that are methylated by NSun2. However, how precisely these processes effect homeostasis is largely unexplored. Therefore, the main aims of my PhD were (1) to dissect the molecular mechanisms of NSun2-mediated RNA methylation pathways that regulate cell survival under normal conditions and in response to oxidative stress, and (2) to investigate the importance of Srsf2 in stem cells using skin as a model system. In the context of RNA modifications, firstly I described how NSun2-expressing cells enrich for transcripts related to enhanced cell survival. Subsequently, by metabolically profiling wildtype and patient-derived dermal fibroblasts carrying loss-of-function mutations in the NSUN2 gene, I showed that the absence of NSun2 is synonymous to an energy-saving, low-translating and stressed cellular state. I further confirmed that lack of NSun2 was sufficient to instigate a cellular stress response, by monitoring BIRC5, a member of the inhibitor of apoptosis family. To further answer whether lack of NSun2 enhanced the susceptibility of patient cells to external stress stimuli, I next exposed them to oxidative stress and measured transcriptional and translational changes. I discovered that NSun2 is required to adapt global protein synthesis to the stress response, while NSun2-depleted cells failed to do so. This was concurrent with NSun2-depleted cells enriching for transcripts related to mRNA degradation and negative regulators of protein translation in response to stress. Generally, since loss of NSun2-driven methylation in tRNAs triggers their cleavage into small ncRNA fragments by angiogenin, I asked how angiogenin or tRNA-derived ncRNAs affect translation levels. In the presence of NSun2, angiogenin alone did not reduce global protein synthesis, yet tRNA fragmentation was required to modulate translation levels. Finally, to uncover how the lack of NSun2 influenced tRNA cleavage and methylation patterns in response to stress, I exposed wildtype and patient cells to sodium arsenite and measured the abundance of tRNA-derived fragments and occurrence of methylation events. With this I discovered unique tRNA fragmentation patterns and global RNA methylation profiles for wildtype and NSun2-depleted cells, that can account for the underlying molecular and phenotypical differences in response to stress. In the context of alternative splicing, and since the cellular functions of Srsf2 are largely unknown, I explored its role in cellular survival and differentiation. By conditionally deleting SRSF2 in two different stem cell populations of the mouse epidermis, I observed significant thickening of the epidermis, altered expression of cell proliferation and stem cell differentiation markers, and distorted hair follicle structures. Moreover, I demonstrated that lack of Srsf2 promotes skin regeneration following injury, thus strongly indicating that Srsf2 is required for normal skin development and regeneration after injury. In summary, my research suggests that NSun2-mediated RNA methylation pathways orchestrate transcriptional and translational programmes in response to external stress stimuli, and my studies are the first to show that the alternative splicing factor Srsf2 is required for stem cell differentiation in skin.

APA, Harvard, Vancouver, ISO, and other styles

50

Widemann, Émilie. "Analyse fonctionnelle de cytochromes P450 de la famille CYP94 et des amidohydrolases IAR3 et ILL6 dans le catabolisme hormonal des jasmonates chez Arabidopsis thaliana." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAJ121/document.

Full text

Abstract:

Les jasmonates jouent des rôles essentiels en réponse aux stress environnementaux et dans le développement des plantes. Jasmonoyl-isoleucine (JA-Ile), la forme hormonale active, est sous un contrôle métabolique strict. Nos études biochimiques, génétiques et métaboliques ont montré que l’inactivation de JA-Ile est contrôlée par 2 voies, l’une oxydative par les cytochromes P450 CYP94 et l’autre hydrolytique par les amido-hydrolases IAR3 et ILL6. Ces enzymes définissent une grille métabolique vers de nombreux jasmonates. Ces conversions constituent un mécanisme général contrôlant le turnover de JA-Ile et les réponses induites, opèrant après blessure, infection par le champignon Botrytis cinerea ou le développement floral. En outre, les CYP94s oxydent le conjugué Jasmonoyl-Phenylalanine (JA-Phe) accumulé dans les feuilles blessées. Les CYP94s catalysent la carboxylation de JA-Ile et de JA-Phe via un intermédiaire aldéhyde, le JA-Ile-aldéhyde étant accumulé in vivo. Ces travaux élucident un nouveau catabolisme hormonal de plantes et son impact sur un réseau métabolique dynamique et complexe par l’action concertée de deux familles d’enzymes Jasmonates are plant molecules playing essential roles in response to environmental stresses and in plant development. Jasmonoyl-Isoleucine (JA-Ile) is an active hormonal form of jasmonates so it is crucial for the plant to control its levels. Biochemical, genetic and metabolic studies showed that JA-Ile inactivation after wounding is controlled by two pathways, based on oxidations by cytochromes P450 of the CYP94 family and on cleavage by the amido-hydrolases IAR3 and ILL6. These enzymes also define a pathway for tuberonic acid (12OH-JA) production from JA. CYP94-catalyzed oxidations seem to be a general mechanism to control JA-Ile hormone turnover, jasmonate signaling and responses as it also occurs upon infection by the fungus Botrytis cinerea and in floral development. CYP94s oxidize also the Jasmonoyl-Phenylalanine (JA-Phe) conjugate accumulated in wounded leaves. CYP94s mediated JA-Ile and JA-Phe carboxylation includes an aldehyde intermediate, that of JA-Ile being accumulated in vivo.This work highlights the dynamic metabolism of jasmonate derivatives in a complex branched network involving the concerted action of two enzyme families

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Wounding'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles