Дисертації з теми "Explant cultures"
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Teixeira, Marta Carolina Jesus. "Patient-derived explant cultures for cancer modelling." Master's thesis, Universidade Nova de Lisboa. Instituto de Tecnologia Quimica e Biológica António Xavier, 2018. http://hdl.handle.net/10362/130073.
Повний текст джерелаАнотація:
"Cancer remains one of the deadliest diseases in the world. The process of drug discovery to find new drugs for oncology treatment takes more than a decade of research and it is associated with high attrition rates during clinical trials. One of the most common reasons claimed for the poor efficiency of new developed drugs is the lack of physiological relevance of the in vitro models used to select the novel compounds and to evaluate their potency. The role of tumor microenvironment on tumor progression and drug sensitivity is being increasingly studied and it is expected to provide significant clues for the development of novel therapies. Therefore, the incorporation of microenvironment features on cancer cell models during pre- clinical stages of research has the potential to improve significantly their predictive value. (...)"N/A
2
Ahmed, Najma Ayesha. "Studies on the regulation of chorionic gonadotropin production in explant cultures of human placenta." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74342.
Повний текст джерелаАнотація:
The effects of various steroid hormones on human chorionic gonadotropin (hCG) production and placental viability were investigated using an explant culture model of human placenta.Placental hCG production was assessed using two different methods: (a) hCG concentrations in media recovered from cultures were measured by radioimmunoassay and (b) tissue levels of hCG in cultured placentae were determined immunohistochemically; both were evaluated before and after exposure to steroid hormones. In first trimester placentae, progesterone and dehydroepiandrosterone (DHEA) increased hCG concentrations both in collected medium and levels in cultured placentae. Estradiol increased the levels of hCG in tissues but not in media. Cortisol increased concentrations in media but did not alter tissue levels. Testosterone decreased hCG levels in media, but had no effect on hCG placental content. In third trimester cultures, progesterone and DHEA were the only hormones studied which increased concentrations of hCG in media; estradiol, cortisol and testosterone had no effect. Progesterone, estradiol and DHEA, alone or in combination, extended the viability of first trimester placental explant cultures from approximately 7 to 30 days. There was a significant relationship between placental viability and tissue hCG levels (r = 0.73, P $<$ 0.001). The concentrations of hCG, progesterone and estradiol in human placentae were determined at various times through gestation. These studies suggest that a temporal relationship exists between the placental levels of hCG and these steroids, and that they may be significant determinants of growth and differentiation of the placenta in vivo. Furthermore, these investigations support the hypothesis that hCG production by the placenta is subject to paracrine regulation by steroid hormones.
3
Baydoun, Martha. "Développement d’un modèle de culture tridimensionnelle à partir d’explants entériques pour l’étude de la cryptosporidiose." Thesis, Lille, 2018. http://www.theses.fr/2018LIL1I003.
Повний текст джерелаАнотація:
Plus de 20 % des cancers sont dus à une infection virale, bactérienne ou parasitaire. En effet, le parasite Cryptosporidium parvum (C. parvum) qui est capable d’induire, chez des souris immunodéprimées, le développement d'adénocarcinomes invasifs au niveau gastro-intestinal. Cependant, la compréhension de la pathogénicité de Cryptosporidium a été limitée par l'absence d'un système de culture en continu et à long terme. Il est donc indispensable d’améliorer les systèmes de culture in vitro en mimant le plus possible les conditions de l’in vivo. J’ai participé tout d’abord à la réalisation d’une étude épidémiologique sur des patients Libanais atteints ou non de néoplasies/adénocarcinomes digestifs. Le taux d’infection à Cryptosporidium était significativement plus élevé chez les patients atteints de cancers coliques comparativement aux autres groupes de patients. Offrant ainsi de nouveaux arguments en faveur d’un lien entre l’infection à Cryptosporidium et la pathologie cancéreuse chez l’homme. Ensuite, j’ai développé un modèle de culture tridimensionnelle (3D) à partir d’un côlon murin adulte. Ce système a permis le maintien de l’infection pendant 35 jours et il a mis en évidence le développement in vitro de lésions néoplasiques 27 jours post infection. Il s’agit, de la première description d'une induction de néoplasies intraépithéliales de bas grade dans un système de culture 3D, par un parasite. Afin d’automatiser ce système, j’y ai associé un dispositif de microfluidique. Ce dernier a permis le maintien de la culture pendant 8 jours. Il s’agit de la première description d'une culture tissulaire d’intestin sur un dispositif microfluidique viable pour 8 joursAlmost 20% of cancers are due to a viral, bacterial or parasitic infection. For instance, Cryptosporidium parvum (C. parvum) was found to induce the development of an invasive digestive adenocarcinomas in an experimental model of SCID mice.However, the understanding of the pathogenesis of Cryptosporidium has been limited by the lack of a long-term culture system. It is therefore essential to improve the in vitro culture systems by trying to mimic the in vivo conditions. Firstly, the association between Cryptosporidium infection and cancer development was investigated through an epidemiological study among cohorts of Lebanese patients with or without recent diagnosis of digestive cancer before any treatment. A high rate of Cryptosporidium was detected in biopsies from Lebanese patients with digestive neoplasia/adenocarcinoma. These results showed that Cryptosporidium is associated with human colon cancer being maybe a potential etiological agent of this disease. In the second part, a three dimensional (3D) Cryptosporidium culture model was developed from adult murine colon. This system allowed the reproduction of neoplasic lesions at 27 days post-infection, providing new evidence of the role of the parasite in the induction of carcinogenesis. This is the first description of a low-grade intraepithelial neoplasia induction after parasite infection in a 3D culture. Finally, in order to automatize the culture, a microfluidics device for explant culture was designed. An explant culture was maintained for almost 8 days using this microfluidic device. To our knowledge, this is the first description of a gut tissue culture on a microfluidic device that was viable for 8 days
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Gerfin-Moser, Andrea Michaela. "Excitatory amino acid receptor expression : localisation in pigeon brain and modulation in rat hippocampal explant cultures by epileptiform activity /." [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10918.
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Fougeray, Sylvie. "Toxicologie cellulaire de liquides de dialyse péritonéale sur des cultures de cellules mésothéliales de premier explant provenant de sujets IRC (insufisants rénaux chroniques) et IRC." Montpellier 1, 1996. http://www.theses.fr/1996MON13514.
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6
許霖慶 and Lam-hing Hui. "Studies on explant regeneration and morphogenesis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1985. http://hub.hku.hk/bib/B3120692X.
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Hui, Lam-hing. "Studies on explant regeneration and morphogenesis /." [Hong Kong : University of Hong Kong], 1985. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1231481X.
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Penrod, Leah Vee. "The Effects of EPA and DHA on the Uterine Inflammatory Response in Mares during In Vitro Culture of Endometrial Tissue." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/145149.
Повний текст джерелаАнотація:
Uterine inflammation is one of the causes of a poor uterine environment. This can result in early embryonic loss in the mare due to an inhibition of or an increased secretion of prostaglandin F2α (PGF2α ). Oxytocin binds to endometrial cell receptors to activate prostaglandin synthesis. Increased secretion or accumulation of PGF2α within the uterus due to uterine inflammation can cause luteolysis and result in early embryonic loss. Supplementation with polyunsaturated fatty acids (PUFAs) has been shown to influence prostaglandin production in many species, although the effects on the mare remain unknown. Equine endometrial biopsies were collected and used to establish endometrial epithelial cell and explant cultures to determine the release of PGF2α and PGFM in response to oxytocin stimulation. Endometrial explant cultures were used to determine the inhibitory effects of Atosiban, an oxytocin receptor antagonist, and Indomethacin, a cyclooxygenase –2 inhibitor, on PGF2α secretion. Endometrial explant cultures were challenged with oxytocin (250 nM) and PGF2α concentrations were measured over time. The effects of PUFAs on equine endometrial prostaglandin production were determined using endometrial biopsies harvested on day two of behavioral estrus. Equine endometrial cells were established and shown to replicate in culture and on a basement membrane matrix. Equine endometrial explants stimulated with oxytocin had increased secretion of PGF2α and PGE2 and the secretion of PGF2α was inhibited through an oxytocin receptor antagonist and Cox inhibition. Endometrial explants stimulated with lipopolysaccharide had increased secretion of PGF2α and PGE2, however oxytocin stimulated to a greater extent than LPS. Supplementation with PUFAs, specifically DHA, decreased the secretion of PGF2α and PGE2, however AA and EPA failed to influence this response. Expression of mRNA was not influenced by fatty acid supplementation, however was altered by stimulus. Therefore DHA influences the inflammatory response in vitro through mechanisms other than enzyme expression. Decreased PGF2α production associated with PUFA supplementation in vivo, creates a likely approach for decreasing early embryonic loss associated with post breeding inflammation commonly seen in the equine industry.
9
José, Andrea Alessandra Filomena Brasil Vieira. "Efeito do ácido linoléico conjugado trans-10, cis-12 na regulação da lipogênese e expressão gênica em culturas de tecido adiposo de suínos em crescimento." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/11/11139/tde-08022006-143005/.
Повний текст джерелаАнотація:
O objetivo deste estudo foi avaliar os efeitos do ácido linoléico conjugado (CLA), especificamente do isômero trans-10, cis-12 em culturas de explante de tecido adiposo de suínos, em crescimento.The objective of this study was to evaluate the effects of conjugated linoleic acid (CLA), specifically the tnas-10, cis-12 isomer on cultures of adipose tissue explants from growing pigs.
10
Amaral, Antonio Francisco de Campos. "Comportamento in vitro de explantes de matrizes de cenoura (Daucus carota L.) tratadas com variáveis níveis de potássio." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-14082003-165946/.
Повний текст джерелаАнотація:
O crescimento de plantas, órgãos, tecidos e células in vitro depende do desenvolvimento de meios de cultura otimizados para a perfeita interação de componentes essenciais como fitorreguladores, fonte de carbono e nutrientes minerais. Os fatores que limitam o crescimento de órgãos ou tecido in vitro são similares a aqueles que limitam o crescimento in vivo. Com o objetivo de testar a influência do estado nutricional de plantas matrizes de cenoura Daucus carota Link em potássio na morfogênese in vitro, plantas obtidas de sementes germinadas em substrato e cultivadas em vasos com areia em condições de casa de vegetação, foram submetidas a tratamentos com soluções nutritivas contendo variáveis níveis de potássio. Decorridos 30 e 60 dias de tratamento, explantes dessas plantas (internódios) foram coletados, desinfetados e inoculados em meio de cultura sólido de MS contendo também diferentes concentrações de potássio e acrescido de 0,1mg.L -1 da auxina 2,4-D buscando indução de calogênese na ausência de luz. Diferenciação celular via embriogênese somática foi conseguida em ausência de auxina em condições de fotoperíodo de 16/8 horas (claro/escuro). A avaliação da calogênese foi feita aos 60 dias após a inoculação, com base na massa de matéria fresca e seca dos calos formados por explante. A avaliação da diferenciação celular (número de plantas/explante) e taxa de diferenciação celular (número de plantas/g de matéria seca de calos) foi realizada após 30 dias de cultivo em condições de luz. A indução de calogênese e crescimento celular nos explantes de matrizes tratadas foi influenciada pelo tratamento pelos níveis de K + na solução nutritiva e pela duração dos tratamentos. Explantes de matrizes tratadas com alta concentração de K + resultaram em indução e crescimento de calos em matéria fresca e seca inversamente proporcional à concentração de K + no meio de cultura tanto para tratamento por 30 dias como para 60 dias. Tratamentos de curta duração (30 dias) com altos níveis de K + nas soluções nutritivas e baixos níveis de K + no meio de cultura influenciaram negativamente a regeneração de plantas (nº plantas/explante) nos calos dos explantes das matrizes tratadas. No entanto, taxas mais altas de diferenciação celular (nº plantas/g de matéria seca de calos) ocorreram nos calos de explantes de matrizes tratadas por 30 dias com solução nutritiva contendo maiores níveis de potássio e inoculados em meio de cultura contendo concentrações iguais ou maiores de que a do meio MS.The growth of plants, organs, tissues and cells in vitro culture depends on the development of optimized culture medium for the perfect interaction among essential components such as phytoregulators, carbon source and minerals nutrients. The factors limiting the growth of organs or tissues in vitro conditions are similar to those limiting growth in vivo conditions. The objective of this work was aimed at studying the influence of the potassium nutritional status of matrixes plants of carrot Daucus carota Link on the in vitro morphogenesis. Matrixes plants were obtained from seeds germinated in organic substratum and cultivated in plastic pots containing washed sand in greenhouse conditions. The matrixes plants were then submitted to treatments with nutrients solutions containing variable potassium levels. After 30 and 60 days treatment, explants (internodes) were collected, disinfested and inoculated in solid culture medium of Murashige and Skoog (MS) containing different potassium concentrations and supplemented with 0,1mg.L -1 of 2,4-D for callogenesis induction in dark conditions. Cell differentiation by somatic embryogenesis was pursued by culturing the calli in auxina-free same culture medium in growth room under photoperiod of 16/8 hours (light/dark). The evaluation of the callogenesis induction and cell growth was carried out 60 days after explants inoculation, based on the mass of fresh and dry matter accumulation on each explant. The evaluation of cell differentiation (plant formed/explant) and of cell differentiation rate (number of plants formed/g of dry matter of callus) was carried after 30 days of culturing under light conditions. Callogenesis induction and cell growth on the explants of treated matrixes plants were affected by the potassium treatment levels in the nutrient solution and by the duration of the treatments. Explants from treated plants with the higher K + concentrations showed callus induction and growth inversely proportional to the concentration of K + in the culture medium for both (30 and 60 days) treatment duration. However the callogenesis accumulated after 60 days treatment was twice as much as that of 30 days treatments. Short time treatments duration (30 days) with higher levels of K + in the nutrient solutions and low concentrations of K + in the culture medium influenced the cell differentiation negatively (nº plants/explant) in the callus of the explants from treated plants. Cells from calli induced on explants from matrixes plants for 30 days were more morphogenic than the cells in the 60 days treatment where high callogenesis was observed. Also better cell differentiation rate was observed on calli induced on explants from treated matrixes plants with nutrient solutions containing the highest potassium levels and inoculated on MS culture medium containing highest potassium concentrations.
11
Mount, Seth. "Serum-Free Xenogen-Free Culture Conditions Support Human Explant-Derived Cardiac Stem Cell Growth." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35678.
Повний текст джерелаАнотація:
Autologous explant-derived cardiac stem cell (EDC) therapies are a promising therapy for ischemic cardiomyopathy, but straightforward clinical translation is limited by traditional culture conditions which are often supplemented with ill-defined and xenobiotic components such as fetal bovine serum. Therefore, we investigated the influence of a commercially sourced serum-free (SF) xenogen-free medium on human EDC yield, phenotype, in vitro measures of EDC performance, and post-infarct cardiac repair using an immunodeficient mouse model of acute myocardial infarction. Despite reduced production of several pro-cardiogenic cytokines, SF EDCs promoted similar vessel formation, circulating stem cell recruitment and cardiogenic differentiation as compared to standard cultures. Transplant of SF EDCs into immunodeficient mice 1 week after myocardial infarction boosted post-ischemic repair beyond that of standard EDCs by enhancing viable myocardium within the infarct. These findings demonstrate that serum-free culture methods provide a superior cardiac-derived cell product with ready clinical translatability.
12
Van, Lerberghe Nadine. "Phénotypes comparés des fibroblastes dermiques de souris vieillissant dans l'animal et dans différentes conditions de culture: explants, cultures sur substrats plan, cultures en gels de collagène. (Immunocytochimie photonique et microscopie électronique)." Doctoral thesis, Universite Libre de Bruxelles, 1986. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/213522.
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Murray, Colin Alexander. "Periradicular disease (PRD) : development of a novel explant culture model to investigate the cytokine network." Thesis, University of Glasgow, 2005. http://theses.gla.ac.uk/5370/.
Повний текст джерелаАнотація:
Periradicular disease (PRD), a localised chronic pathologic inflammatory reaction in response to continuous microbial stimuli from necrotic, infected dental root canals, represents a substantial health care burden. The efficacy of available therapies is sub-optimal and identification of new therapeutic targets is essential. Elucidation of functional interactions between PRD cell populations and tissue matrix and between PRD lesion and cells within the surrounding dentoalveolar bone matrix is prerequisite to this. I hypothesise that the cytokine milieu is central in orchestrating these interactions. I generated a novel human explant tissue culture system to investigate the pathogenesis of PRD. I aimed: (1) to investigate the expression of multiple cytokines, but particularly IL-18, within the human lesion and to elucidate their likely biological contribution towards PRD; (2) to investigate the presence of and functional interactions between inflammatory mediators within human PRD that influence bone homeostasis; and (3) to phenotype the contribution of the PRD fibroblast. Four hundred and fifty patients were recruited after obtaining informed consent. PRD tissue was obtained for investigations, of which 310 specimens were examined in a novel explant culture system. Endogenous cytokine release was readily detected in vitro confirming significant inflammatory activity within chronic PRD and facilitating a detailed analysis for the first time of the complex interactions between cytokine activities in PRD.
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Reinsberger, Claus. "Do cultured human skin explants elaborate coeliac antigen, possibly even Tissue-Transglutaminase?" [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966537475.
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Hoepker, Veit Helmut. "Trophic actions of myenteric plexus explants on striatal neurons in cell culture." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283397.
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Wetten, Andrew C. "The influence of light regime on growth and differentiation of cultured tomato explants." Thesis, Oxford Brookes University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315398.
Повний текст джерелаАнотація:
Growth of cultured tomato (Lycopersicon esculentum Mill.) leaf explants was assessed in response to quantitative variation in the light regime. Exposure to a range of photon flux densities (PFD) resulted in distinct PFD optima for callus, shoot and root initiation. Incubation of explants under a range of temperatures also resulted in a wide range of growth responses both in terms of tissue type and dry matter production. It was observed that manipulation of PFD by varying the separation between culture and light source was accompanied by a non-uniform temperature regime between PFD treatments. Therefore irradiance-dependent growth responses cannot be accurately interpreted with this arrangement unless additional compensatory heating is employed to maintain a uniform temperature regime throughout PFD treatments. Culture of explants on media shielded from illumination resulted in a distinct organogenesis response from explants exposed to full illumination when the media contained indole-3-acetic acid (IAA). A comparison of the morphogenic response to PFD with that produced under a matrix of exogenous auxin and cytokinin concentration combinations indicated that morphogenesis may be influenced by PFD-dependent depletion of IAA. A high performance liquid chromatography study of auxin depletion from basal medium showed that IAA was rapidly removed when illuminated and that the rate of removal was proportional to the prevailing PFD and the concentration of basal salts. The inclusion of the photosynthetic inhibitors 3-(3,4-dichlorophenyl)I,I-dimethylurea and 3-amino-l,2,4-triazole in the basal medium resulted in inhibition of explant growth and elimination of the sequential change in the culture vessel headspace CO2 concentration apparent during the light/dark cycle in noninhibited controls. This indicates that in vitro photosynthesis made a significant contribution to PFD-dependent explant growth. While culture of explants under a range of photoperiods of uniform PFD produced a range of growth responses, a uniform growth response occurred when explants were exposed to 16 hour and 24 hour photoperiods of uniform photon dose achieved through PFD variation. This demonstrates that growth was enhanced as a function of the increase in total incident radiation rather than through an effect of the photoperiod per se. Dark or low PFD incubation of explants for the first 4 days of culture significantly enhanced growth as a result of reduced photodestruction of IAA during a period of optimal tissue sensitivity to exogenous auxin.
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Omwenga, George Isanda. "Callus Development and Organogenesis in Cultured Explants of Cowpea (Vigna unguiculata (L.) Walp." Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4655/.
Повний текст джерелаАнотація:
Cowpea, Vigna unguiculata (L.) Walp is an excellent source of protein, vitamins and minerals and a major food crop many parts of Africa. Optimal production levels are hampered by insect pests and diseases. Biotechnological techniques such as tissue culture and genetic engineering can aid in the development of varieties with resistance to insect pests and diseases. The objective of this study was to investigate conditions necessary for the development of a reproducible tissue culture system that can be applied to regenerate transformed cells from culture. The in vitro manipulation of cowpea using Murashige and Skoog (MS) medium, auxins and cytokinins resulted in the formation of callus and rhizogenesis. Calli that were formed were separated into six classes based on color and texture. Yellowish friable callus, yellowish compact, soft yellowish callus and green and white were composed of largely vacuolated cells and were non-regenerative. Friable green callus was the most prevalent callus type and could form of roots in some hormone combinations. Green spots were formed on hard compact green callus. The green spots became nodular, forming root primordia and ultimately giving rise to roots. None of the six calli types gave rise to the formation of shoots. Embryogenic callus was induced from cowpea explants cultured on MS medium supplemented with dicamba and picloram. Embryogenic suspension cultures were initiated from callus induced on MS supplemented with 3.0 mg/L dicamba or picloram and conditions for maintenance of embryogenic suspension cultures were evaluated. Somatic embryos were formed in suspension cultures. Attempts to convert and germinate the somatic embryos resulted in the formation of callus or formation of appendages on the somatic embryos or in the death of the embryos. The appendages formed roots on prolonged culture. Further research is needed to determine appropriate optimal conditions for embryo conversion and germination and ultimately plant recovery from culture.
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Davies, Catrin Meleri. "Validation of an ex vivo, loaded, circumfusion culture for living cancellous bone explants." Thesis, Cardiff University, 2005. http://orca.cf.ac.uk/54559/.
Повний текст джерелаАнотація:
The goal of this project was to validate a novel, mechanically loaded culture system, for the maintenance of cancellous bone explants ex vivo. The Zetos system utilised cancellous biopsies (5 mm high, 10 mm diameter) from ovine distal femora, bovine distal metacarpals and human femoral heads loaded daily for 300 cycles, at 1 Hz, giving 4,000 microstrain. Prior to culture, qualitative evaluation of bone density and overall morphology was conducted. These tissues were highly variable with bovine tissue being the most homogenous with regards to density and that each species contained different ratios of red and yellow marrow. The viability of bone cells and matrix synthesis were analysed using a variety of techniques. The outcome of this study was that diffusion constraints were the major limitation of this system. Chamber design was not optimal for bathing the explants, which was inferior to submerged static culture in centrifuge tubes. Harvesting the tissue created damage to the bone core that resulted in a maximal volume loss of 36%, which also encouraged unwanted growth of a fibrous-like tissue over the explant periphery in a wound-like response, possibly enhanced by foetal calf serum in the media. Nevertheless, 3H-glycine incorporation detected proteins synthesised during day 7 and 14 of culture. Collagen was the predominant protein synthesised. Fluorochrome labelling demonstrated human bone apposition during culture, but was unsuccessful with bovine and ovine tissue. Mechanically loaded explants were qualitatively more viable than unloaded disuse explants and submerged static controls. These results demonstrate cell viability at least 15 days post-harvest. If the limitations can be improved, then there is potential for this system to become routinely used in bone research. This system would provide a future means to allow bone-biomaterial interactions and interfaces to be studied, reducing, refining and replacing the need for animal experimentation.
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Morin, Caroline. "Caractérisation des propriétés mécaniques et électrophysiologiques des explants bronchiques mis en culture organoïde." Mémoire, Université de Sherbrooke, 2005. http://savoirs.usherbrooke.ca/handle/11143/3812.
Повний текст джерелаАнотація:
La culture des muscles lisses des voies respiratoire (MLVR) induit une dédifférentiation rapide d'un phénotype contractile vers un phénotype prolifératif, ceci peut être dû à la perte de l'architecture tridimensionnelle du tissu et à des modifications des signalisations inter et intracellulaire. Cette problématique a été contournée en mettant en culture organoïde, pendant 3 à 7 jours, des bronches de cobaye dans un milieu DMEM-F12 en présence ou en absence de 10% sérum et en comparant leurs propriétés contractiles et électrophysiologiques à celles des préparations natives. Ce nouveau modèle in vitro se caractérise par une hyperréactivité, aux agents muscariniques, histaminergiques, sérotinergiques et aux eïcosanoïdes. Les propriétés relaxantes des explants aux différents agonistes sont également amplifiées. Une sensibilité accrue au U-46619 (agoniste du récepteur au thromboxane) a été mesurée par rapport à celles des tissus natifs."--résumé abrégé par UMI.
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Morin, Caroline. "Caractérisation des propriétés mécaniques et électrophysiologiques des explants bronchiques mis en culture organoïde." [S.l. : s.n.], 2005.
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Williams, Adam. "Proteomic studies of an explant model of equine articular cartilage in response to pro-inflammatory and anti-inflammatory stimuli." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14371/.
Повний текст джерелаАнотація:
Osteoarthritis (OA) is characterised by cartilage degradation, inflammation and pain within synovial joints. OA is a major cause of morbidity in the elderly human population and in companion animals such as horses. Changes in expression and activity of pro-inflammatory cytokines, chemokines and catabolic mediators contribute towards OA progression, which can be studied using in vitro culture models and proteomic approaches. This project studied the secretome from an in vitro model of equine articular cartilage, aiming to develop understanding of cartilage biology and degradative processes. These studies also aimed to identify protein markers relevant to this explant model for screening anti-inflammatory properties of novel therapeutics. To evaluate responses to OA associated pro-inflammatory IL-1β and the non-steroidal anti-inflammatory drug (NSAID), carprofen, time courses of protein release were established in the explant model. The cartilage secretome contained cartilage extracellular matrix (ECM), non-ECM and intracellular proteins, all of which were identified by high-throughput mass spectrometry (MS). Semi-quantitative differences in protein release were reported between untreated control and IL-1β stimulated cartilage by MS. The release of glycosaminoglycans (GAGs) initiated by IL-1β was delayed when carprofen was present. The proteomic sample preparation method was adapted to deplete high abundance proteins that can hinder the detection of low level proteins in high-throughput MS analysis. Three depletion approaches were applied: CPC precipitation, concanavalin A lectin chromatography and Proteominer™ technology. These approaches provided additional identifications of the non-ECM secreted proteins MMP-10 and IL-9, and of additional intracellular proteins. Further optimization of these methods could further enhance the detection of low level proteins. Proteins identified by MS analysis of the cartilage secretome were assessed using quantitative western blotting analysis. Carprofen significantly reduced IL-1β stimulated release of MMP-1, MMP-3, MMP-13 and a fibronectin degradation product. Levels of clusterin were reduced by IL-1β and carprofen treatments. These specific proteins were shown to be markers of IL-1β stimulated inflammation and degradative processes, which can be significantly reduced by an anti-inflammatory such as carprofen. This thesis describes the use of proteomics with other approaches to study the effects of IL-1β and carprofen on release of several important structural, metabolic and inflammatory related components from cartilage. Carprofen was beneficial in decreasing certain aspects of inflammation and degradation, including significantly reducing release of MMPs and their catabolic products (fibronectin and GAGs) from the ECM. The equine explant model can be further studied with high-throughput MS to assess responses to various stimuli and detect released proteins. In conclusion, anti-degradative effects and MMP inhibition can be specifically monitored within this in vitro equine cartilage model, to screen efficacy of therapeutics and putative anti-inflammatories to relieve OA.
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Jesty, James Henry Frederick. "The behaviour of coconut and wheat leaf explants in tissue culture : a comparative study." Thesis, Cardiff University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305476.
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Nikolakis, Georgios [Verfasser]. "Towards the establishment and characterization of a human skin explant co-culture model with SZ95 sebocytes / Georgios Nikolakis." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2014. http://d-nb.info/1056908041/34.
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Matsunaga, Mami. "Initiation of Supporting Cell Activation for Hair Cell Regeneration in the Avian Auditory Epithelium: An Explant Culture Model." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263555.
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Davies, Sallie. "IGFBP-1 production in an explant culture system of human Fallopian tube mucosal cells and influences upon that production." Thesis, University of Southampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427456.
Повний текст джерела
26
Karekla, Ellie. "Improving therapeutic approaches for the treatment of non-small cell lung cancer using an ex-vivo explant culture system." Thesis, University of Leicester, 2015. http://hdl.handle.net/2381/39930.
Повний текст джерелаАнотація:
Lung Cancer is the leading cause of cancer death worldwide in both males and females. Non-small cell lung cancer (NSCLC) accounts for ~80-85% of lung cancers. NSCLC is a very heterogeneous disease, both genetically and histologically, and there is an increasing list of mutations and copy number alterations in cancer associated genes. Several drugs that could potentially improve lung cancer outcomes are in development and some have entered clinical trials. However, the current established preclinical models, particularly animal xenografts, are not always predictive of patient outcome and there has been a large attrition of clinical candidate drugs at the Phase III stage. The aim of this project was to establish a primary NSCLC explant culture system with the view to developing a better platform to test the efficacy of existing drugs as well as novel drug combinations. The tissue architecture and tumour heterogeneity of individual NSCLC patients can be examined in an ex-vivo NSCLC explant culture system which maintains viability and proliferation in a short period of 24 hours + recovery (16-20 hours). Even though there is a moderate effect of cultivation, the ex-vivo NSCLC explant culture system can be used for assessing in situ drug responses over short periods. Responses of explants were assessed after treatment with cisplatin, MEK and PI3K inhibitors singly and in combination and TRAIL and ABT-737 singly and in combination in the presence or absence of cisplatin. This model points towards being more predictive of patient outcome in clinical studies than in vitro studies or animal models. The data show that the explant system has the potential to improve on current preclinical models for lung cancer or other solid cancers and help the drug development process achieve greater successes in the clinic. The model could provide a platform for personalising treatment to each patient and for identifying effective biomarkers for drug responses.
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Jones, William Dylan. "Epidermal adhesion molecules in human wounds and development of a tissue explant culture system to investigate modification of their expression." Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/55575/.
Повний текст джерелаАнотація:
When cutaneous injury involves disruption of the basement membrane, keratinocytes must disassemble their complex attachment to it, enabling lateral migration over a wound surface consisting of a new provisional matrix. Integrin cell adhesion molecules have already been characterised as prime mediators of this process in experimental human wounds. However, very little is known about the role played by integrins as well as other epidermal adhesion molecules such as syndecans in more complex chronic wounds. In this study, a human model of rapidly healing surgically induced wounds and pilonidal excision wound tissue was used to establish the previously documented expression of epidermal adhesion molecules in the acute healing process. Chronic venous leg ulcer wound tissue was then taken as representing the process of chronic wounding and used to investigate its effect on these adhesion molecules. Differences were found between the expression of adhesion molecules in acute and chronic wounds. In particular as pi expression was decreased in chronic wound epidermis. As a result, a tissue explant culture system was developed to investigate the possibility of modifying its expression on chronic wound keratinocytes. Characterisation of venous leg ulcer explant tissue within this system highlighted the inherent heterogeneity of the tissue, leading to a large degree of variability in the levels of analytes such as IL-8 measured within it. Pilot experiments with two biopsies suggested that aspi expression could be up regulated on chronic wound keratinocytes in response to an inflammatory stimulus. However, further development of this system will be required to reduce the variability within it, before real changes in cell behaviour in response to exogenous stimuli can be demonstrated. Given the difficulties in extrapolating data from animal to human tissue, development of models such as this could prove invaluable in trying to understand the complexities of chronic wounds.
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Oliveira, Leandro Silva de. "Propagação de Eucalyptus cloeziana F. Muell." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-05052014-154718/.
Повний текст джерелаАнотація:
O Eucalyptus cloeziana se destaca pelas propriedades tecnológicas da sua madeira, principalmente em razão da sua durabilidade, densidade e resistência. Entretanto, essa espécie apresenta limitações quanto ao enraizamento adventício de estacas, dificultando a obtenção de mudas clonais e o avanço nos programa de melhoramento da espécie. Nesta perspectiva, o presente trabalho teve por objetivo avaliar a micropropagação de E. cloeziana a partir de materiais juvenis e adultos como uma técnica para a propagação da espécie. Para tanto, o trabalho foi dividido em quatro partes. No primeiro estudo, estabeleceu-se um protocolo de organogênese indireta de E. cloeziana a partir de hipocótilos e cotilédones. No segundo estudo avaliou-se o resgate de matrizes adultas de E. cloeziana através da indução de brotações epicórmicas em megaestacas. No terceiro estudo definiu-se um protocolo de micropropagação via proliferação de gemas axilares de matrizes adultas de E. cloeziana. Por último, no quarto estudo avaliou-se o rejuvenescimento in vitro de matrizes adultas de E. cloeziana por meio da micropropagação via proliferação de gemas axilares e a microestaquia, a partir das matrizes rejuvenescidas in vitro,para comprovar a viabilidade do cultivo in vitro como alternativa de propagação da espécie. A organogênese indireta de E. cloeziana mostrou-se possível e dependente do tipo de explante, dos reguladores de crescimento, suas concentrações e combinações utilizadas nas diferentes fases de morfogênese. As brotações adventícias foram micropropagadas e aclimatizadas com sucesso, obtendo-se mudas clonais de E. cloeziana. No resgate das matrizes adultas de E. cloeziana ocorreu maior indução de brotações epicórmicas para as megaestacas coletadas na época do ano com maior pluviosidade e temperatura. O diâmetro médio das megaestacas, compreendido entre 2,0 e 5,0 cm, correspondeu ao mais adequado para a obtenção de maior número de brotações epicórmicas no resgate das matrizes adultas de E. cloeziana. O protocolo de micropropagação das matrizes adultas de E. cloeziana foi estabelecido com sucesso, utilizando como explantes, brotações epicórmicas induzidas nas megaestacas. A multiplicação in vitro das microcepas foi realizada com êxito no meio de cultura WPM suplementado com BAP e ANA, cujas concentrações variaram entre os genótipos. Os tratamentos de \"pulse\" com GA3 não foi adequado para promover o alongamento in vitro das brotações, o qual foi obtido coma redução da concentração do BAP (0,1 mg L-1). A aclimatização e o enraizamento ex vitro das microestacas foi realizada com sucesso nos miniestufas, garantindo a obtenção de mudas clonais das matrizes adultas de E. cloeziana para a composição de um microjardim clonal. As microcepas das árvores matrizes de E. cloeziana apresentaram diferentes taxas de multiplicação in vitro, apresentando especificidades dos materiais genéticos à micropropagação. Os resultados da microestaquia das matrizes rejuvenescidas in vitro de E. cloeziana corroboraram as evidências de rejuvenescimento desses genótipos durante a micropropagação. Além disso, constatou-se que outros fatores, além da maturidade, podem estar atuando diretamente na recalcitrância do E. cloeziana ao enraizamento adventício. Dessa forma, comprovou-se a importância da micropropagação como uma ferramenta para a clonagem de E. cloeziana, abrindo perspectivas para investigações futuras para otimizar os métodos de propagação da espécie.Eucalyptus cloeziana has importance for its wood technologic characteristics, mainly the durability, density and resistance. Moreover, this species has limitations on adventitious rooting of cuttings, having difficulties to obtain clonal seedlings and to advance in the improvement programs. In this perspective, the present work aimed to evaluate the E. cloeziana micropropagation by juvenile and mature explants as a technique for propagation this specie. Therefore, the work was divided into four basic studies. The first study was the establishment of the protocol to indirect organogenesis to E. cloeziana hypocotyls and cotyledons. In the second study evaluated the rescue of E. cloeziana adult matrices for epicormic shoots induction in crow branches. In the third study was definite a micropropagation protocol by axillary branching of E. cloeziana adult matrices. Finally, in the fourth study was evaluated the in vitro rejuvenation of E. cloeziana adult matrices to micropropagation by axillary branching and the micro-cutting technique of in vitro rejuvenated matrices to prove the in vitro culture viability to the propagation of this specie. The indirect organogenesis E. cloeziana was dependent of explant type and growth regulator and its concentration used in the different morphogenesis phases. The adventitious shoots were multiplicities and acclimatized with success to obtain E. cloeziana clonal seedlings. The vegetative rescue results of E. cloeziana adult matrices showed a higher induction epicormic shoots from branches collected in warmer and rain season. The medium diameter between 2.0 and 5.0 cm was considered the better to obtain higher epicormic shoots number in vegetative rescue. The micropropagation protocol of E. cloeziana adult matrices was realized with success using epicormic shoots, induced in the branches, like explants. The shoots in vitro multiplication was realized on WPM medium culture, supplemented with BA and NAA. The better growth regulators concentrations were different for each genotype. Treatments pulse with GA3 was not suitable to promote the elongation of shoots in vitro, which was obtained by the BA concentration reduction at 0.1 mg L-1. The in vitro shoots acclimatization and ex vitro rooting was performed in mini-incubators with success and it permit to obtain clonal seedlings from E. cloeziana adult matrices to form a clonal micro-garden. The shoots of E. cloeziana adult matrices showed different in vitro multiplication rates with specific-genotype responses to micropropagation. The micro-cutting technique results of E. cloeziana adult matrices provide evidence that occurred in vitro rejuvenation of these genotypes, during the micropropagation. Therefore, the nursery results showed that other factors, not only maturation, can be involved in the adventitious recalcitrance of E. cloeziana. In conclusion, the importance micropropagation like a biotechnological tool to propagation of E. cloeziana was proved and opened important perspectives for future investigations to optimize the propagation methods for this specie.
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Polesi, Natalia Pimentel Esposito. "Estudo da comunidade bacteriana endofítica e de sua manifestação na micropropagação de Eucalyptus benthamii." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-22092015-143023/.
Повний текст джерелаАнотація:
Eucalyptus benthamii tem se mostrado especialmente vantajoso como alternativa ao cultivo em regiões frias, justificando esforços para o estabelecimento de protocolos para sua micropropagação. Porém, as matrizes são preferencialmente selecionadas quando adultas (material apresenta menor competência morfogênica), tornando a micropropagação dependente de maior número de subcultivos e maior tempo para se reverter o material ao rejuvenescimento. Assim, a redução das perdas in vitro tem merecido atenção, como por exemplo, as manifestações endofíticas, que exigem maximização da eficiência da cultura e adequações no protocolo, visando minimizá-las, possibilitando melhorar o entendimento das relações estabelecidas e mantidas entre os endófitos e seu hospedeiro durante a micropropagação. Dessa maneira, foram utilizadas minicepas provenientes de duas fontes de miniestacas coletadas a partir do brotamento de gemas epicórmicas de megaestacas da base da copa e de brotamentos do anelamento da base do tronco, de uma matriz de E. benthamii com 13 anos de idade, estabelecidas em minijardim clonal sob condição de casa de vegetação, com o objetivo de avaliar como se dá a multiplicação, sob diferentes condições de cultivo, das duas fontes de explantes (minicepas); analisar se a frequência e intensidade das manifestações endofíticas são afetadas pelas diferentes condições de cultivo; investigar a ocorrência de alterações na comunidade bacteriana endofítica devido à alteração das condições de cultivo e fase da micropropagação (in vivo = minicepas, e in vitro = microcepas, material alongado e enraizado). Visando atender estes objetivos, a pesquisa se dividiu em duas partes. Na primeira (capitulo 3) o desenvolvimento, os aspectos morfofisiológicos, histoquímicos e a manifestação endofítica foram avaliados na multiplicação das duas fontes de explante sob diferentes meios e condições de cultivo. Na segunda (capítulo 4) as comunidades bacterianas endofíticas foram analisadas por meio de PCR-DGGE, baseada na região V6 do gene 16S DNAr. Os resultados mostraram que as microcepas provenientes de megaestaca tiveram melhor desenvolvimento independentemente do tratamento e maior frequência de manifestações endofíticas, comparando-se com as de anelamento. As comunidades bacterinas endofíticas foram distintas entre as amostras in vivo e in vitro, e se alteraram ao longo dos subcultivos e nas amostras alongadas e enraizadas. As diferenças existentes no desenvolvimento das microcepas podem ser inerentes à totipotencialidade do material, mas também podem ser afetadas, tanto pela ocorrência de manifestação, quanto pela comunidade bacteriana endofítica mais ou menos sensível ao processo de micropropagação, auxiliando ou prejudicando o desenvolvimento in vitro de seus hospedeiros. Cabe destacar, ainda, que mesmo em um sistema asséptico e ambientalmente controlado, os microrganismos endofíticos que resistiram a todo processo de desinfestação e cultivo, não estão \"adormecidos\", muito pelo contrário podem se alterar em quantidade à medida que seu hospedeiro é submetido a um novo sistema de cultivo (introdução) ou uma nova fase dentro da micropropagação (multiplicação → alongamento e enraizamnento) ou, ainda, ao longo dos subcultivos. Sendo assim, a complexa rede de relações das plantas com seus endófitos não cessa durante o cultivo in vitro, ao contrário mantém-se dinâmica.Eucalyptus benthamii has proven to be especially advantageous as an alternative culture in cold regions, justifying efforts to establish protocols for micropropagation. However, the matrices are preferably selected when adults (material with lower morphogenic efficiency), making micropropagation more dependent of subcultures and too longer to reverse the material to rejuvenation. Thus, reduction of losses in vitro has deserved attention, such for example the endophytic manifestations that require the maximization of efficiency culture and adjustments to the Protocol, in order to minimize them, enabling better understanding of the relations established and maintained between endophytes and its host along micropropagation. For this, mini-stumps were used from two sources of mini-cuttings collected from the epicormic shoots of mega-cuttings from the treetop base and shoots from girdling from the trunk base, both of one E. benthamii matrix with 13 years of age established in clonal mini garden under greenhouse condition, aimed to evaluate how is the multiplication of two sources of explants (mini-stumps) under different growing conditions; analyze how the endophytic manifestations frequency and intensity are affected by different conditions; investigate the changes to occurrence in the endophytic bacterial community due to the variation of culture conditions and micropropagation phase (in vivo = mini-stumps, and in vitro = micro-stumps, elongated and rooted materials). In order to meet these objectives, the research was divided in two parts. In the first (chapter 3) the development, morphophysiological aspects, histochemical and endophytic manifestation were evaluated in the multiplication of the two explants sources from different media and culture conditions. In the second (chapter 4) endophytic bacterial communities were analyzed by PCR-DGGE based on the V6 region of 16S rDNA gene. The results showed that micro-stumps from mega-cuttings had better development regardless of treatment and increased frequency of endophytic events, comparing with the girdling. Endophytic bacterial communities were different between samples in vivo and in vitro, and have changed over the subcultures and the elongated and rooted samples. The differences in the development of micro-stumps can be explained by the totipotentiality inherent to the material, but may also be affected by both the manifestation occurrence and the endophytic bacterial community more or less sensitive to the micropropagation, helping or harming the in vitro development of their hosts. We also highlight that even in an aseptic and environmentally controlled system, the endophytic microorganisms that resisted the whole process of disinfection and cultivation, are not \"asleep\", quite the opposite may change in quantity when your host is subjected to a new cultivation system (in vitro establishment) and a new phase within the micropropagation (multiplication → stretching and enraizamnento), or even along the subcultures. This way, the complex network of relationships of the plant with their endophyte does not cease during the in vitro culture, unlike remains dynamic.
30
Hirota, Keisho. "Live imaging analysis of the growth plate in a murine long bone explanted culture system." Kyoto University, 2019. http://hdl.handle.net/2433/242405.
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Hussein, Salem Hussein. "Aspects of embryogenesis and organogenesis in the in vitro culture of various explants of the eggplant (Solanum melongena L.)." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316471.
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Attfield, Elizabeth Margaret. "An analysis of the stages of organogenesis in leaf explants of Nicotiana tabacum L. CV. Xanthi NC. cultured in vitro." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303344.
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Wang, Shiping. "Peptides as amino acid sources for the synthesis of secreted proteins by mammary tissue explants and cultured mammary epithelial cells." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/39137.
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34
Liu, Hongxiang. "Effects of pulsed electromagnetic fields on extracellular matrix composition of embryonic chick sternal cartilage explanted to culture." Thesis, Royal Veterinary College (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362746.
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Fávero, Pâmela. "Transformação genética de três cultivares de laranja doce a partir de explantes de plantas adultas." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-11022011-094748/.
Повний текст джерелаАнотація:
A dificuldade de transformação de tecido adulto de espécies lenhosas é uma barreira ainda a ser contornada para a maioria das cultivares de laranja doce de importância na citricultura brasileira. Esta dificuldade está relacionada ao alto nível de contaminação, ao baixo potencial regenerativo e à baixa capacidade de transformação de tecidos adultos de espécies lenhosas. Assim, o objetivo deste trabalho foi otimizar o protocolo de transformação genética de tecido adulto de três cultivares de laranja doce. Com ajustes no cultivo in vitro, foi possível obterem-se gemas adventícias transgênicas via Agrobacterium tumefaciens de três cultivares de laranja doce (Citrus sinensis L. Osbeck), Hamlin, Pêra e Valência, utilizando material adulto como fonte de explantes. As gemas transgênicas foram identificadas como transgênicas pelo teste histoquímico GUS e confirmados pela análise de PCR, a qual mostrou a amplificação de um fragmento 817 pb, correspondente a parte do gene uidA amplificada. A utilização de meio de co-cultivo com a adição de auxinas e citocininas (2,0 mg L-1 de 2,4 D; 2,0 mg L-1 de AIA e 1,0 mg L-1 de 2-iP), foi o mais eficiente para as três cultivares avaliadas. Meios de seleção com altas concentrações de citocinina (3 mg L-1) favoreceram a regeneração e, conseqüentemente, a transformação de gemas adventícias para as três cultivares estudadas. O uso da sonicação não foi eficiente para diminuir a contaminacão endofítica. Além disso, esta operação diminuiu a eficiência de transformação dos explantes. As eficiências médias de transformação genética encontradas para as três cultivares foram 2,5% para laranja Hamlin, 1,4% para laranja Pêra e 3,7% para laranja Valência.The difficulty of tissue transformation of adult woody species is still an obstacle to be overcome for most sweet orange cultivars in the Brazilian citrus industry. This difficulty is related to the high level of contamination, low regenerative potential and low transformation capacity of adult tissues of woody species. Thus, the objective of this work was to optimize the protocol for genetic transformation of adult tissue of three cultivars of sweet orange. Therefore, with in vitro culture adjustments, it was possible to obtain transgenic adventitious buds though Agrobacterium tumefaciens of three sweet orange cultivars (Citrus sinensis L. Osbeck), Hamlin, Pêra and Valencia, using adult material as explants source. The transgenic buds were identified as transgenic by the GUS histochemical test and confirmed by the PCR analysis, which showed fragment amplification of 817 bp corresponding to the part of the amplified uidA gene. The use of co-culture media rich in auxins and cytokinins (2.0 mg L-1 of 2.4 D, 2.0 mg L-1 of AIA and 1.0 mg L-1 of 2-iP) was more efficient for all three cultivars. Selection media with high concentrations of cytokinin (3 mg L-1) promoted the regeneration and, consequently, the transformation of adventitious buds in the three cultivars. The use of sonication was not effective to reduce endophytic contamination. Moreover, this procedure reduced transformation efficiency of explants. The average efficiencies of genetic transformation for the three varieties were 2.5% for Hamlin, 1.4% for Pêra and 3.7% for Valência.
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León, Enrique Asterio Benítez. "GERMINAÇÃO, ESTABELECIMENTO, REGENERAÇÃO E CALOGÊNESE IN VITRO EM EXPLANTES DE AÇOITA-CAVALO (Luehea divaricata Mart. & Zucc.)." Universidade Federal de Santa Maria, 2010. http://repositorio.ufsm.br/handle/1/8668.
Повний текст джерелаАнотація:
Conselho Nacional de Desenvolvimento Científico e TecnológicoThe advance of biotechnology in forestry has favored techniques of in vitro propagation of species that present difficulties in reproduction by sexual seeds. Luehea divaricata Mart. & Zucc, a member of the Malvaceae family, is a species that has suffered in recent decades, a large reduction in the areas occupied by natural populations, because of its use in the manufacture of furniture. Additionally, it presents slow and irregular germination and seed viability is very uneven, characteristics that contribute to a reduced ability to recover natural populations. Considering the potential for the application of techniques of tissue culture in the mass propagation of this species, this study aimed to: develop a methodology to promote an efficient surface disinfestation of seed germination in order to in vitro evaluate the ability of two types of explants of seminal in performing the in vitro establishment; evaluate the nodal segments isolated from of plants grown in vitro germination depending on the addition of BAP and NAA in different concentrations, in the WPM nutrient medium, and, finally, analyze the calli seetings responses of leave fragments to different concentrations of BAP and NAA in WPM. The project was developed at the Laboratory of Tissue Culture at the Center for Biotechnology and Breeding of the Federal University of Santa Maria. The seeds used were collected by Fepagro/Forests and the plants obtained were used as source of explants for the experiments in tissue culture. We tested the effect of different concentrations and immersion times of seeds in mercuric chloride, and also the influence of fungicides Dicarboximida and Benzimidazole in the surface disinfestations. To in vitro establish were evaluated apical and nodal segments isolated from plants after 60 days in vitro culture. The surface disinfestation of L. divaricata seeds with mercuric chloride was efficient, promoting a satisfactory germination and lack of phytotoxicity. Moreover, the use of fungicides, after disinfestation procedure with mercuric chloride, showed toxic effect on plants, failed to control contamination by microorganisms. The L. divaricata in vitro establishment was successful from both the apical and nodal segments, especially those that result in higher leaf development. Concentrations of BAP and NAA tested dont not result in a hormonal balance appropriate to promote optimal responses in vitro multiplication of L. divaricata from the culture of nodes segments and the presence of BAP influence significantly the calli induction, unlike NAA which dont not affect the calli formation on leaf fragments. Further studies should be performed to optimize the in vitro surface desinfestation, multiplication and callus induction capable of producing a larger number of aseptic cultures to continue to other steps in tissue culture. Finally, studies that aim to contribute to the L. divaricata micropropagation should continue, since the species presents barriers to the spread by seeds that can be overcome by tissue culture.
O avanço da biotecnologia na área florestal tem favorecido as técnicas de propagação in vitro de espécies que apresentam dificuldades na reprodução via sementes. Luehea divaricata Mart. & Zucc (açoita-cavalo), integrante da família Malvaceae, é uma espécie florestal que sofreu, nas últimas décadas, grande redução das áreas ocupadas por populações naturais, em função do interesse de seu uso na fabricação de móveis vergados. Adicionalmente, apresenta germinação lenta e irregular e a viabilidade das sementes é muito desuniforme, características que contribuem para uma reduzida capacidade de recuperação natural das populações. Considerando-se a potencialidade da aplicação de técnicas de cultura de tecidos na propagação massal dessa espécie, o presente trabalho teve como objetivos: desenvolver uma metodologia que promova uma eficiente desinfestação superficial de sementes, visando à germinação in vitro; avaliar a capacidade de dois tipos de explantes de origem seminal em realizar o estabelecimento in vitro; avaliar a regeneração de segmentos uninodais isolados de plantas oriundas da germinação in vitro em função da adição da citocinina BAP e da auxina ANA, em diferentes concentrações, ao meio nutritivo WPM; e, por fim, analisar as respostas calogênicas de fragmentos foliares, face às diferentes concentrações de BAP e ANA em meio nutritivo WPM. Os trabalhos foram desenvolvidos no Laboratório de Cultura de Tecidos, do Núcleo de Biotecnologia e Melhoramento do da Universidade Federal de Santa Maria. Foram utilizadas sementes coletadas pela Fepagro/Florestas e, as plantas obtidas, foram utilizadas como fonte de explantes para os experimentos de cultura de tecidos. Foram testados o efeito de diferentes concentrações e de tempos de imersão das sementes em bicloreto de mercúrio, e, também, a influência de fungicidas Dicarboximida e Benzimidazol na desinfestação superficial. Para o estabelecimento in vitro, foram avaliados segmentos nodais e apicais caulinares isolados de plantas, após 60 dias de cultivo in vitro. A desinfestação superficial das sementes de açoitacavalo com bicloreto de mercúrio foi eficiente, promovendo uma germinação satisfatória e ausência de fitotoxicidade. Por outro lado, o uso de fungicidas, após procedimento de desinfestação com bicloreto de mercúrio, além de apresentar efeito tóxico para as plantas, não controlaram a contaminação por microrganismos. O estabelecimento in vitro de açoitacavalo foi efetuado com sucesso, tanto a partir de segmentos apicais, como segmentos nodais, com destaque para estes pelo maior desenvolvimento foliar. As concentrações de BAP e ANA testadas, não resultam em um balanço hormonal adequado à promoção de respostas otimizadas na multiplicação in vitro de açoita-cavalo, a partir do cultivo de segmentos nodais; a presença de BAP influencia, significativamente, a calogênese, ao contrário de ANA, que não afeta a formação de calos em fragmentos foliares de açoitacavalo. Estudos adicionais devem ser realizados no sentido de otimizar a desinfestação superficial, a multiplicação e a calogênese in vitro, permitindo a obtenção de um número maior de culturas assépticas para dar continuidade a outras etapas da cultura de tecidos. Finalmente, os estudos que visam contribuir para a micropropagação em açoita-cavalo devem prosseguir, já que a espécie apresenta entraves para a propagação por sementes que podem ser superados pela cultura de tecidos.
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Silva, Herbert Gomes da. "O explicar: a explicação humana na perspectiva do observador como ser biológico e cultural." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/81/81133/tde-25022013-133523/.
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Nesta pesquisa estudamos e defendemos o fenômeno do explicar a partir da perspectiva do observador. O sistema conceitual que ressalta o observador como ser biológico e cultural fundamenta-se na Teoria da Biologia do Conhecer de Humberto Maturana e Francisco Varela. A explicação é um fenômeno humano e ao mesmo tempo biológico que só existe quando é aceito pelo observador. A interação é possível quando a constituição biológica do observador permite a perturbação do meio externo à sua dinâmica interna, relacionada diretamente ao sistema nervoso que funciona em clausura operacional. O observador é um ser autopoiético, e por isso, sofre constantes modificações de sua estrutura nos processos interacionais da práxis do viver sem, no entanto, perder a sua identidade. Quando acontece de mais de um observador interagir e se modificar mutuamente, alem de estar em acoplamento estrutural, passam a conviver e possuir um conjunto de comportamentos que dependem dessa história coletiva (ontogenia). Para ilustrar modelos de explicações aceitas, coletamos enunciados com estudantes do 9º ano do ensino fundamental em uma escola pública de São Paulo. Dos enunciados, foi possível criar categorias que demonstraram a existência de elementos nas explicações dos estudantes oriundos do contexto da práxis do viver, o que indicaria que o ensino de ciências deve refletir sobre esse como elemento fundamental para referenciar a linguagem e os métodos de ensino, tornando a ciência como algo natural ao fazer de seus observadores que buscam conhecer aquilo que esta no fazer dos cientistas, pois \"Todo fazer é um conhecer, e todo conhecer é um fazer\". O observador autopoiético está na relação indissociável entre linguagem, constituição biológica e cultura.In this research we study and defend the phenomenon of the explain from the observer\'s perspective. The conceptual system that emphasizes the observer as a biological and cultural being based on the Theory of the Biology of Knowledge by Humberto Maturana and Francisco Varela. The explanation is a human phenomenon and simultaneously biological that only exists when is accepted by the observer. The interaction is possible when the biological constitution of the observer allows an interference of the external environment to his internal dynamics, directly related to the nervous system that operates on operational clausura. The observer is an autopoietic being, therewith suffers constant changes in his structure in the interactional processes of the praxis of the living, and yet, no losing his identity. When there is more than one observer that interacts and modifies each other, besides being in a structural coupling, they begin to live and have a set of behaviors that depend on their collective history (ontogeny). To illustrate models of accepted explanations has been collected statements with students of the 9th elementary grade of a public school in Sao Paulo. From that statements, it was possible to create categories that demonstrated the existence of elements in the students\' explanations from the context of the praxis of the living, which would indicate that the education of science should reflect on it as a key element to reference the language and teaching methods, making science as something natural to make its observers who seek to know what is on scientists doings, because \"All doings is a knowledge, and all knowledge are doings\". The autopoietic observer is in an indissociable relationship between language, biological constitution and culture.
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Faria, Daniele Vidal. "Otimização do protocolo de organogênese in vitro em explantes hipocotiledonares de urucum (Bixa orellana L.)." Universidade Federal de Viçosa, 2014. http://www.locus.ufv.br/handle/123456789/7577.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Com a substituição dos corantes sintéticos pelos naturais, o urucum (Bixa orellana L.) tem alcançado crescente importância no mercado internacional, por ser a principal fonte do apocarotenoide bixina, utilizada para vários fins na indústria, sendo o único responsável por suprir a demanda do comércio mundial. Neste cenário busca-se a compreensão da via e a clonagem dos genes envolvidos na via de biossíntese da bixina, visando principalmente à obtenção de plantas melhoradas, bem como para inserção de genes da própria via em outras espécies comerciais de cultivo amplo e mecanizado. Atualmente trabalhos relacionados à transformação genética em B. orellana são escassos e há a necessidade de otimizar métodos de regeneração in vitro que viabilizem a obtenção de plantas transgênicas com desempenho superior em nível de produção de bixina. Dessa forma o objetivo desse trabalho foi testar diferentes explantes hipocotiledonares de urucum, citocininas e diferentes meios de cultura na organogênese, desenvolvimento e enraizamento de brotos de B. orellana. Foi observado que explantes hipocotiledonares contendo tamanho de 6,0; 8,0; e 10,0 mm de comprimento apresentaram eficientes respostas organogênicas, sendo observada a formação de até 10 brotos por explante quando cultivados no meio JADS suplementado com zeatina. Em explantes hipocotiledonares de urucum seccionado longitudinalmente e posicionados com a secção em contato com o meio de cultura JADS acrescido de zeatina foi observado a formação de 17,11 brotos por explante. Explantes hipocotiledonares pré-tratafdoscom Zeatina, BAP e TDZ (0,1 e 0,5 mg L-1) não diferiram significativamente na indução de brotos em comparação com explantes não tratados com citocininas. O meio de cultura JADS se mostrou mais eficiente em comparação ao MS, induzindo maior número de brotos. Os brotos apresentaram-se mais alongados, vigorosos e totalmente não hiperhídricos. Os brotos induzidos em meio JADS apresentaram também maior número e maior desenvolvimento de raízes em comparação com brotos induzidos em meio MS de urucum, consequentemente, devido ao desenvolvimento superior, brotos induzidos no meio JADS, apresentaram 100% de sobrevivência durante a fase de aclimatização ex vitro. O presente trabalho possibilitou otimizar as respostas organogênicas em diferentes explantes hipocotiledonares de urucum, concentrações de fitorreguladores e meios de cultura, os quais podem ser utilizados para estudos futuros de transformação genética de urucum.
With the substitution of synthetic dyes to natural, annatto seeds (Bixa orellana L.) industry is increasing the international market importance, given that this species is the main natural and commercial source of the apocarotenoid bixin. This plant pigment is used for various industrial purposes, and it is the main pigment that has been comerciallized worldwide. In this scenario, it is necessary to understand the metabolic pathway and the cloning of the genes involved in the bixin biosynthesis, aiming to obtain improve plants or even to add genes of interest related to bixin biosynthesis to other commercial crop species of broad and mechanized cultivation. Currently, there are few publications related to genetic transformation in B. orellana, being necessary to optimize in vitro protocols that will allow the obtainining of transgenic plants with higher level of bixin production. Thus, the aim of this work was to test different hypocotyl explants of annatto, the cytokinin effect and different media on in vitro organogenesis and rooting of B. orellana adventitious shoots. It was observed that hypocotyl explants with 6.0, 8.0 and 10 mm longer showed the best organogenic responses inducing up to 10 shoots per explant when cultured in JADS medium supplemented with zeatin. Hypocotyl explants of annatto induced more shoots when they were sectioned longitudinally and positioned with the section in contact with the JADS medium in presence of zeatin, which stimulated the induction of 17.11 shoots per explant. The hypocotyl explants pre-treated with zeatin, BAP and TDZ (0.1 and 0.5 mg L- ) did not differ significantly on shoot induction from control explants which were not treated with cytokinins. The JADS medium was more appropriate for shoot induction in comparison with MS medium. The shoots induced on JADS medium were more vigourous, longer and non-hiperhidric. The JADS medium affect positively the rooting, given that the shoots displayed more roots and well developed roots in comparison with shoots induced on MS medium. Consequently, due to the best development on JADS medium, the shoots supported the ex vitro acclimatization phase with 100% of survival. This work possibilited the optimization of organogenesis from different hypocotyl explants, plant growth regulator concentrations and culture media, which can be used in further studies of annatto genetic transformation.
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Vieta, i. Corcoy Pep Anton. "Nous formats en la comunicació de la química. Explorant el seu paper en el foment de la cultura i les vocacions científiques." Doctoral thesis, Universitat de Girona, 2017. http://hdl.handle.net/10803/404101.
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Throughout this thesis I was involved in different science communication projects where research and innovation have been applied to improve existing proposals and exploring new formats without forget the evaluation of the impact of the outreach activity on the public, in promoting vocations and improving the social perception of science. Many of the social changes occurred during the course of the thesis have been taken as challenges of it becoming new opportunities. Among them I highlight the social networks, such as new digital communication tools, or the popularization of open knowledge, as well as flipped classroom or MOOCs as innovative methodologies in the field of educationAl llarg d’aquesta tesi s’han dut a terme projectes de comunicació científica on la innovació i la recerca han estat aplicades per millorar les propostes existents, explorar altres formats i, tot experimentant, proposar novetats sense deixar de banda l’avaluació de la repercussió de l’activitat divulgativa sobre el públic, en el foment de vocacions i en la millora de la percepció social de la ciència. Molts dels canvis socials ocorreguts durant el transcurs de la tesi han estat presos com a reptes de la mateixa esdevenint oportunitats ben aprofitades. Entre ells destaquen les xarxes socials, com a noves eines de comunicació digital, o la popularització del coneixement obert, així com els MOOC o la flipped classroom, com a metodologies innovadores en l’àmbit de l’educació
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Mosquim, Paulo Roberto. "Cultura in vitro de "Explants" de soja (Glycine max CLJ Merril) desenvolvimento da tecnica e avaliação de diferentes fontes de nitrogenio." [s.n.], 1989. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315230.
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Orientador: Ladaslav SodekTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: No presente trabalho desenvolveu-se um sistema de ¿explant¿ que possibilitou verificar o transporte e o metabolismo de substâncias nitrogenadas, em caules, vagens, tegumentos das sementes e cotilédones das sementes de soja (Glycine Max [L] Merril) cv. Santa Rosa. O ¿explant¿ utilizado continha apenas uma vagem completatmente expandida com duas sementes (pesando em torno de 200 mg) um caule com cerca de 6 cm de comprimento e um pedaço de pecíolo remanescente. A base do caule era então mergulhada em frasco contendo um meio de cultura definido, pH 5.0, mantido a 2ºC, em banho de gelo. As vagens permaneceram a uma temperatura de 25ºC, sob luz contínua em uma câmara de germinação. Nos testes para verificar as melhores condições do meio de cultivo que assegurassem melhores crescimentos das sementes verificou-se que: Não houve necessidade da adição de cofatores ou vitaminas. A melhor composição de macronutrientes do meio foi a de CHANDLER et al (1983). As melhores concentrações de sacarose estão entre 33,3 e 66,6 mg/ml do meio e a de glutamina foi de 6,26 mg/ml. Os caules apresentaram pouca reserva de carboidratos, mas continham reservas de substâncias nitrogenadas. Não houve necessidade da substituição dos meios de cultivo durante o período de análise. ...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital
Abstract: Not informed.
Doutorado
Doutor em Ciências Biológicas
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Patel, Taranjeet. "Using dynamic cultural theories to explain the viability of international strategic alliances : a focus on Indo-French alliances." Thesis, Open University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422015.
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Capaldi, Flávia Regina. "Avaliação de diferentes fontes de nitrogênio em explantes de Cryptomeria japonica D.Don. "elegans" cultivados in vitro: análises bioquímicas e relações entre reguladores vegetais." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-30072002-162030/.
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A Cryptomeria japonica D. Don. "elegans" é uma conífera pertencente à família Taxodiaceae, que apresenta crescimento rápido e boas respostas à fertilização. Dez variações nas concentrações de nitrato e amônio presentes no meio de cultura MS foram realizadas no cultivo 'in vitro' de brotações obtidas a partir de explantes primários de ápices caulinares durante 90 dias. A cada 30 dias foram avaliados, a taxa de crescimento relativo e o incremento em massa vegetal seca. Ao final de 90 dias, foram realizadas análises dos teores de proteínas solúveis totais, aminoácidos solúveis totais, carboidratos não-estruturais totais e eletroforese de proteínas totais em gel de poliacrilamida. Os tratamentos que exibiram resultados mais satisfatórios foram utilizados em um experimento com diferentes relações auxina/citocinina, onde foram avaliadas a produção de brotações e a altura média das mesmas aos 30, 60 e 90 dias de cultivo. As concentrações de nitrato e amônio entre 25 e 31mmol.L -1 e até 5mmol.L -1, respectivamente, foram as mais efetivas para o crescimento e desenvolvimento do material vegetal cultivado 'in vitro'. Durante o experimento com diferentes concentrações de ANA e BAP, foi possível observar que a produção de brotações, etapa essecial para um processo de micropropagação eficiente, foi superior quando as combinações entre nitrato e amônio foram 22,5 + 2,5mmol.L -1 e 25,0 + 5,0mmol.L -1.Cryptomeria japonica D. Don. "elegans" is a fast-growing tree belonging to the Taxodiaceae and it is considered a responsive species 'in vitro'. The aim of this work was to evaluate the effect of ten different concentrations of nitrate and ammonium in morphogenesis 'in vitro' of Cryptomeria japonica D. Don. "elegans" explants. Analysis of relative growth rate, total soluble proteins, total soluble aminoacids, total non structural carbohydrates and electrophoresis of total proteins was performed in order to observe the role of different nitrogen sources on the growth and development of the explants cultivated 'in vitro'. The concentratios of nitrate and ammonium that showed the best results were selected and used in an experiment with different concentrations of NAA and BAP to observe the shoot production. Each experiment was analised at the 30 th , 60 th and 90 th days of culture. The biochemical analysis was performed only at 90 th day of cultive. Concentrations from 26 to 31mmol.L -1 of NO3 - and lower than 5mmol.L -1 of NH4 + were the most effective for growth and development of the explants. However, the experiment with different concentrations of NNA and BAP showed that the best shoot production was achieved on 22,5mmol.L -1 of NO3- + 2,5mmol.L -1 of NH4 + and on 25,0mmol.L -1 of NO3 - + 5,0mmol.L -1 of NH4 + and with 2,0mg.L -1 of BAP + 1,0mg.L -1 of NNA.
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Borsoi, Nice Livio. "Desinfecção de explantes e cultivo in vitro de Piretro da Dalmácia (Chrysanthemum cinerariaefolium Vis. cv. Vacaria)." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-05082009-103629/.
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As atividades que envolvem a floricultura vêm se destacando positivamente no cenário econômico do agronegócio brasileiro. Dentre as espécies de plantas utilizadas para este fim ressaltam-se as espécies pertencentes à família botânica Asteraceae, principalmente as do gênero Chrysanthemum. A espécie C. cinerariaefolium Vis. (Piretro da Dalmácia) é mundialmente cultivada visando à produção de aleloquímicos que apresentam atividades de inseticidas naturais (piretrinas). No Brasil chegou a ser produzida para esse fim em larga escala, no município de Taquara-RS na década de 30 a 40. Recentemente o interesse de seu cultivo tem aumentado como uma alternativa natural de manejo de pragas como planta ornamental, principalmente para jardins. Contudo, o fato de não produzir sementes férteis limita sua capacidade de propagação massal. Visando aperfeiçoar sua micropropagação foram realizados dois experimentos. No experimento 1 foi avaliado aos 30 dias de cultivo a influência de cinco concentrações de hipoclorito de sódio (10, 20, 30, 40 e 50% do produto comercial Mazzarolo) e cinco tempos de permanência na solução durante a desinfestação dos explantes (5, 10, 15, 20, 25 min.). Ao todo foram isolados 125 meristemas totalizando 25 tratamentos com cinco repetições. Os explantes isolados foram inoculados no meio de isolamento, o qual foi constituído de MS + 1,0 mg.L-1 de BAP + 0,1 mg.L-1 de GA3 + 0,01 mg.L-1 ANA + 30 g.L-1 de Sacarose em 7,0 g.L-1 de Agar. No experimento 2 foi avaliado a influência das diferentes concentrações de hipoclorito e dois tempos de permanência na solução desinfetante sobre a porcentagem de necrose, estruturas amorfas, plântulas formadas e comprimento de brotos. As plântulas regeneradas do experimento 1 foram inoculadas no meio de multiplicação que constou do MS + 0,4 mg.L-1 de Thiamina HCl + 100 mg.L-1 de Mio-Inositol + 0,05 mg.L-1 de ANA + 1,0 mg.L-1 de BAP + 40 g.L-1 de Sacarose e 7,0 g.L-1 de Agar. O pH dos meios foi ajustado em 5,9 antes da autoclavagem. Os resultados obtidos no experimento 1 indicaram que quanto maior o tempo de permanência na solução, maior a porcentagem de necrose. Porém, quanto menor a permanência maior a taxa de contaminação microbiana. No experimento 2, observou-se que a porcentagem de necrose é maior na concentração de 50%. Não houve influência dos fatores analisados na produção de estruturas amorfas. Para o número de brotos/explante e comprimento de brotos, o melhor desempenho se deu na solução 30%. Porém, a taxa de brotos por explante diminuiu à medida que aumentou o tempo de permanência na solução. Com relação ao comprimento dos brotos, os melhores resultados foram observados até o tempo de 15 minutos de permanência. Assim conclui-se que C. cinerariaefolium Vis. responde positivamente ao cultivo in vitro. A taxa de necrose aumenta à medida que aumenta a concentração de hipoclorito. Por outro lado, a taxa de contaminação aumenta à medida que diminui a concentração da solução desinfetante. A concentração de hipoclorito de sódio e o tempo de permanência na solução desinfetante afetam o número e o comprimento de brotos produzidos nos subcultivos.The activities that involve floriculture have distinguished positively in the economic scenario of the Brazilian agribusiness. Among the plant species used for that purpose it can be distinguished the species belonging to the botanical family Asteraceae, mainly from the genus Chrysanthemum. The species C. cinerariaefolium Vis. is worldwide cultivated in order to produce the alelochemicals, which have activities of natural insecticides (pyretrine). In Brazil it was produced in large scale, in the Taquara-RS County in the decade of 30 to 40. Recently the interest on its cultivation has increased as natural alternative of pest management as ornamental plant, mainly in yards. However, the fact of no seed is produced by the plant that limits its capacity of massal production. In order to optimize its micropropagation two experiments were developed. In the experiment 1 it was evaluated 30 days after cultivation the influence of five concentrations of sodium hipochlorine (10, 20, 30, 40 and 50% of the commercial product Mazzarolo), and five time lengths of the explants permanence in the disinfecting solution (5, 10, 15, 20 and 25 min.). It was isolated 125 meristems, 25 treatments with five replications. The isolated explants were inoculated in isolation media, that was constituted of MS + 1.0 mg.mL-1 of BAP + 0.1 mg.L-1 of GA3 + 0.01 mg.L-1 ANA + 30 g.L- 1 of sucrose in 7.0 g.L-1 of Agar. In the experiment 2 it was evaluated the influence of different concentrations of hipochlorine and two length of time in disinfection solution measuring the percentage of necrosis, amorphous structures, seedlings formed and length of the sprouts. The regenerated seedlings from experiment 1 were inoculate in a medium of multiplication that was of MS + 0.4 mg.L-1 of Thiamine HCl + 100 mg.L-1 of Mio-Inositol 0.05 mg.L-1 of ANA + 1.0 mg.L-1 of BAP + 40 g.L-1 of sucrose and 7.0 g.L-1 of Agar. The pH of the medium was adjusted to 5.9 before the autoclaving process. The results obtained in the experiment 1 indicated that the higher the time length in the solution, the higher is the percentage of necrosis. However, the higher is the permanence of higher rate of microbial contamination. In the experiment 2; it was observed that the percentage of necrosis is higher at the concentration of 50%. There was no influence of the analyzed factors in the yield of amorphous structures. For the number of sprouts/explants and length of sprouts, the better performance was in the solution of 30%. However, the rate of sprouts per explants diminished as the length of time in the solution increased. The best results for sprout length were obtained up to 15 minutes of permanence. Therefore, it can be concluded that C. cinerariaefolium Vis. responds positively to in vitro culture. The rate of necrosis increases as the hipochlorine concentration is higher. On the other hand, the contamination rate increases as the disinfection solution diminishes. The concentration o hipochlorine sodium as the length of time of permanence in the initial disinfecting solution used during the explants disinfection affects the number and the sprout length produced during the subculture.
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Lelu, Marie-Anne. "Embryogenese somatique chez picea abies l. Karst. A partir de cotyledons de jeunes plantes." Paris 6, 1987. http://www.theses.fr/1987PA066485.
Повний текст джерелаАнотація:
Les travaux relatant l'embryogenese somatique chez les gymnospermes sont encore recents et n'ont ete realises qu'a partir de materiel tres juvenile. C'est ce genre d'explant que nous avons utilise comme temoin pour caracteriser et visualiser l'embryogenese somatique. Nous avons par la suite obtenu ce phenomene a partir de cotyledons de jeunes plantes agees de 3 a 7 jours apres germination, places directement en conditions de callogenese. Cependant, le taux de cals embryogenes est ameliore quand les cotyledons subissent un traitement caulogene d'une semaine prealablement; dans nos meilleures conditions experimentales 22,7% de cotyledons forment des cals embryogenes. Ceux-ci, places sur un milieu de multiplication, doivent etre subdivises et repiques tous les 10 a 12 jours afin de favoriser leur proliferation
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Crespo, Rodríguez Noé Cuauhtémoc. "An examination of behavioral, psychological, socio-cultural and environmental factors that may explain gender differences in children's differences in children's physical activity." Diss., [La Jolla] : [San Diego] : University of California, San Diego ; San Diego State University, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p3386765.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2009.Title from first page of PDF file (viewed February 3, 2010). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 139-150).
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Brockhill, Aneta. "How does the analysis of structural violence help to explain the persistence of the Israel-Palestine conflict? : a case study of the barrier." Thesis, University of Plymouth, 2017. http://hdl.handle.net/10026.1/9289.
Повний текст джерелаАнотація:
The Israel-Palestine conflict constitutes one of the longest standing conflicts in modern times. Its continuation has often been attributed to the very nature of the conflict: two peoples pursuing an incompatible goal-ownership of the same piece of land. Violence has constituted a characteristic feature of this struggle, widely employed by the two peoples. The analysis of violence, however, has often been limited to acts of direct and physical violence that can be attributed to an individual subject. This thesis investigates violence in the conflict going beyond this traditional conceptualisation of violence. It employs Johan Galtung’s conceptual and theoretical framework, in which he identifies three types of violence: direct, structural and cultural. This thesis argues that all three types of violence are symbiotic in nature. The underlying assumption in this thesis is simple: violence breeds violence. Thus, in order to understand the persistence of the conflict, it is essential to analyse all three types of violence. The thesis proposes the hypothesis that the continuing failure to address all forms of violence, as well as omitting or minimising the importance of any of them, prevents the possibility of resolving the conflict, and thus has contributed to the protraction of the conflict. In order to examine this assumption empirically, the thesis investigates the violence in the conflict, concentrating on the Israeli barrier. The study poses two central research questions. The first asks what led to the construction of the barrier. The second asks why the barrier remains, and the Israeli occupation continues. The answers to the research questions and the account of violence have been the subjects of two contrasting narratives: Israeli and Palestinian. In order to provide both Israeli and Palestinian contributions to these questions, the thesis is divided into two accounts: Palestinian narrative and Israeli narrative. The empirical analysis of violence in the conflict, embedded in the theoretical framework of Galtung's conceptualisation of violence, and divided into the two narratives, reveals a complex cycle of violence in the conflict. It demonstrates the interconnection between the three types of violence and shows the impact of the violence on the intractability of the Israel-Palestine conflict.
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Alejos, Marcos. "Transient Expression of BABY BOOM, WUSCHEL, and SHOOT MERISTEMLESS from Virus-Based Vectors in Cotton Explants: Can We Accelerate Somatic Embryogenesis to Improve Transformation Efficiency?" Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1609070/.
Повний текст джерелаАнотація:
Upland cotton (Gossypium hirsutum L.) is the world's most prominent fiber crop. Cotton transformation is labor intensive and time consuming, taking 12 to 18 months for rooted T0 plants. One rate limiting step is the necessary production of somatic embryos. In other recalcitrant species, ectopic expression of three genes were shown to promote somatic embryogenesis: WUSCHEL (WUS), SHOOT MERISTEMLESS (STM), and BABY BOOM (BBM). WUS is responsible for maintaining stem-cell fate in shoot and floral meristems. STM is needed to establish and maintain shoot meristems. STM and WUS have similar functions but work in different pathways; overexpression of both together converts somatic cells to meristematic and embryogenic fate. BBM encodes an AP2/ERF transcription factor that is expressed during embryogenesis and ectopic expression of BBM reprograms vegetative tissues to embryonic growth. In prior studies, these genes were constitutively expressed, and cultures did not progress beyond embryogenesis because the embryogenic signal was not turned off. In our study, we set out to use these genes to increase the efficiency of cotton transformation and decrease the time it takes to regenerate a plant. A disarmed cotton leaf crumple virus (dCLCrV) vector delivers WUS, STM, or BBM into cotton tissue cultures through Agrobacterium tumefaciens infection. We propose that virus delivery of embryo-inducing genes is a better approach for transformation because A) inserts more than 800 nucleotides are unstable, and will spontaneously inactivate, B) virus DNA can migrate through plasmodesmata to cells around the infected cell, creating a gradient of embryonic potential, C) the virus DNA does not pass through the germ line and the seed will not contain virus. We propose this method of inducing embryogenesis will facilitate the stable transformation of cotton and will be beneficial to the cotton industry. Ectopic expression of AtBBM, AtSTM, and AtWUS GrWUS:meGFP from a constitutive CaMV 35S promoter produced plants with phenotypes similar to those described in previous studies overexpressing AtBBM, indicating that the AtBBM gene was functional. The cotton cotyledon infiltration of the pART27 constructs showed transformed cells in Coker 312 by GFP localization in the nucleus. Although GFP was detected, no visible embryos appeared from the cotyledon. Cotyledons infiltrated with Agrobacterium harboring overexpression vectors withered and aborted after ~2 weeks. The virus-based vector in tissue culture failed to increase transformation efficiency, resulting in no embryos. The combination of hormone concentration showed no contribution to increasing the transformation efficiency.
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Graff, Curt Gerard. "Course selection theory and college transition seminars: an adaptation of college choice models to explain first-year students' course enrollment behavior." Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/1141.
Повний текст джерелаАнотація:
This dissertation examines the course-enrollment behavior of first-year students at a public Midwestern university. Using the student choice construct, modern college choice theory, and the constructs of habitus, human capital, financial capital, social capital, cultural capital, along with background variables such as gender and locus of control, a course selection theory is proposed to explain students' voluntarily enrollment in a seminar designed to assist with the academic and social transitions to college. The literature review shows numerous studies have been done examining the impacts these courses may have on first-year students' academic performance, retention, and graduation rates. In many of these studies, however, subsets of students were targeted for enrollment and participation in the seminars was not voluntary. In others, students self-select into the first-year transition seminars, raising questions about whether or not their subsequent success is attributable to their participation in these courses. Prior to this study, few, if any, studies have examined enrollment in these first-year seminars as the dependent variable and attempted to explain how various factors impact whether or not students voluntarily choose to enroll.
This quantitative research looked at 7,561 first-year students enrolling in 2006-2007 and 2007-2008 and, using logistic regression, attempted to explain whether or not students chose to enroll in a transition seminar. Data was gathered from institutional offices (Admissions, Registrar, and Student Financial Aid) and through an Entering Student Survey completed by 99% of each entering cohort. Of the 52 independent variables included in the model, 17 were significant in one or more steps (or blocks) of the model.
This study found that students more advantaged in their individual or family college-going resources (e.g., higher ACT-Composite scores or a higher self-evaluation of their ability to appreciate fine arts, music, and literature) are less likely to enroll in the college transition seminar than students that could be described as more disadvantaged in terms of their college-going resources (i.e., an external locus of control, receiving a Pell Grant, and less access to various forms of capital). There is also evidence that students with past experiences where they may have learned the value of community or teamwork through in- and out-of-class experiences may see the first-year transition seminar as a way to begin creating these same types of connections or communities on the college campus. The dissertation concludes with a consideration of implications for future research, theory development, and institutional policy and practice.
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CHOUFFOT, STRUYCKEN BARBARA. "Contribution a l'etude des capacites de multiplication vegetative du shorea curtisii dyer ex king, diphterocarpaceae de malaisie." Strasbourg 1, 1986. http://www.theses.fr/1986STR13138.
Повний текст джерелаАнотація:
Surexploitee pour son bois, infeodee pour son developpement a une mycorhization, dependant d'une production de semences episodique et d'une germination aleatoire, shorea curtisii, incapable en outre de multiplication vegetative spontanee ou par les procedes traditionnels, est tres representatif des dipterocarpacees asiatiques menacees d'extinction rapide. Une mise au point d'un procede de micropropagation in vitro contribuerait a sauvegarder l'espece. L'observation, chez shorea curtisii, de galles epiphylles a organisation de bourgeon abortif suggerant une certaine aptitude des feuilles a la neoformation de meristemes caulinaires, privilegie celles-ci pour larecherche d'une methode de clonage in vitro (. . . )
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Brodlie, Malcolm James. "Development of a primary airway epithelial cell culture model and explanted tissue archive to study the role of neutrophilic inflammation and airway remodelling in cystic fibrosis lung disease." Thesis, University of Newcastle Upon Tyne, 2011. http://hdl.handle.net/10443/1228.
Повний текст джерелаАнотація:
Cystic fibrosis (CF) is the most common inherited life-limiting condition in the United Kingdom. Lung disease, involving retention of mucopurulent secretions, neutrophilic inflammation and endobronchial infection is the major cause of mortality. CF is caused by variants in the CF-transmembrane conductance regulator gene, however the exact pathogenesis of lung disease is not fully understood. Valid experimental models are therefore critical to advance research. I describe the establishment of a successful method to culture primary bronchial epithelial cells (PBECs) from explanted CF lungs removed at transplantation. This technique has yielded an important resource to further study the pathogenesis of CF lung disease. The cytokine interleukin-17 orchestrates the activity of neutrophils and increases mucin gene expression in BECs – two key features of CF lung disease. I demonstrate that interleukin-17 is increased in the airway of people with advanced CF lung disease. I also show evidence suggesting that neutrophils themselves may be a source of interleukin-17 potentially leading to an ever-increasing spiral of inflammation. In a CF mouse model ceramide accumulates in BECs and is associated with neutrophilic inflammation and susceptibility to Pseudomonas aeruginosa infection. Furthermore, amitriptyline treatment normalised ceramide, inflammation and susceptibility to infection. The role of ceramide is a complex area, however, with a divergence of opinion in the literature and paucity of human data. I demonstrate using immunohistochemistry that ceramide is increased in the lower airway epithelium in advanced CF lung disease compared to pulmonary hypertension and unused lung donors and is correlated with neutrophilic inflammation and increased in those colonised with Pseudomonas aeruginosa. Ceramide species C16:0, C18:0 and C20:0 but not C22:0 are increased in lung homogenates of CF lungs compared to pulmonary hypertension measured using the independent technique of high performance liquid chromatographymass spectrometry. Both interleukin-17 and ceramide represent important topics for further translational CF lung disease research.