Дисертації з теми "Root microbiota"
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Aleklett, Kristin Anna Eva. "Examining ecological determinants of community formation and stability in the root microbiota." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/56741.
Повний текст джерелаIrving K. Barber School of Arts and Sciences (Okanagan)
Biology, Department of (Okanagan)
Graduate
Yamashita, José Carlos. "Avaliação da microbiota e da reparação apical e periapical após preparo biomecânico de canais radiculares com diferentes soluções irrigadoras, em dentes de cães com reação periapical crônica /." Araraquara : [s.n.], 2004. http://hdl.handle.net/11449/101639.
Повний текст джерелаBanca: Mario Roberto Leonardo
Banca: Léa Assed Bezerra da Silva
Banca: Igor Prokopowitsch
Banca: Francisco José de Souza Filho
Resumo: O objetivo deste estudo foi avaliar a microbiota presente no sistema canais radiculares antes e após o preparo biomecânico; e as condições histopatológicas da reparação apical e periapical após preparo biomecânico dos canais radiculares de dentes com reação periapical crônica. Foram utilizados 78 canais radiculares de dentes de cães, os quais, após indução de lesão periapical, foram submetidos ao preparo biomecânico utilizando as seguintes soluções irrigadoras: solução de digluconato de clorexidina a 2%, de hipoclorito de sódio a 2,5% ou soro fisiológico. Um grupo controle não recebeu preparo biomecânico. Foram realizadas culturas microbiológicas antes e após 30 dias do preparo biomecânico. Após este período os animais foram mortos para processamento e análise histopatológica. O estudo microbiológico demonstrou que houve redução dos microrganismos nos grupos que utilizaram soluções antimicrobianas (p<0,05), com melhor resultado para a solução de clorexidina. Os grupos que utilizaram solução fisiológica controle apresentaram aumento de microrganismos. No estudo histopatológico, foi observado, de um modo geral, infiltrado inflamatório periapical severo e em grande extensão, severo espessamento do ligamento periodontal e grandes áreas de reabsorção óssea e apical em todos os grupos (p>0,05). Concluiu-se que o emprego de soluções irrigadoras antimicrobianas durante o preparo biomecânico promove redução da microbiota endodôntica, sem a sua eliminação do sistema de canais radiculares em dentes de cães com lesão periapical. A solução de clorexidina a 2% proporcionou maior redução da microbiota que a solução de hipoclorito de sódio a 2,5% (p<0,05). Porém, os resultados histopatológicos demonstram que somente o preparo biomecânico não foi capaz de criar condições para reparação dos tecidos apicais e periapicais.
Abstract: The aim of this study was to evaluate the microorganisms in the root canal system before and after biomechanical preparation and the apical and periapical repair after this biomechanical preparation. The study was performed in 78 root canals of dog's teeth with induced chronic periradicular lesion. There were used the following endodontic irrigating solutions: 2% chlorhexidine digluconate solution; 2.5% sodium hypochlorite solution, saline solution and a control group without biomechanical preparation. The microbiological sampling were performed before and 30 days after the biomechanical preparation. After this period the animals were killed to histological analysis. In the microbiologic study, the results showed that the antimicrobial solutions used reduced the number of microorganisms (p<0.05). The chlorhexidine solution showed better performance. The group that used saline solution and the control group presented an increased number of microorganisms. The histological results showed a severe periapical inflammation, severe thickness of periodontal ligament, apical and osseous resorption in all groups (p>0.05). It was concluded that the antimicrobial endodontic solution reduced but not eliminated the microorganisms present in root canals of dogþs teeth with necrosis and periapical lesion. The chlorhexidine solution was more effective in reducing the number of microorganisms than sodium hypochlorite solution (p<0.05). Although, the histopathological results showed that the biomechanical preparation alone was not capable to promote an adequate condition for the apical and periapical tissues repair.
Doutor
Yamashita, José Carlos [UNESP]. "Avaliação da microbiota e da reparação apical e periapical após preparo biomecânico de canais radiculares com diferentes soluções irrigadoras, em dentes de cães com reação periapical crônica." Universidade Estadual Paulista (UNESP), 2004. http://hdl.handle.net/11449/101639.
Повний текст джерелаConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O objetivo deste estudo foi avaliar a microbiota presente no sistema canais radiculares antes e após o preparo biomecânico; e as condições histopatológicas da reparação apical e periapical após preparo biomecânico dos canais radiculares de dentes com reação periapical crônica. Foram utilizados 78 canais radiculares de dentes de cães, os quais, após indução de lesão periapical, foram submetidos ao preparo biomecânico utilizando as seguintes soluções irrigadoras: solução de digluconato de clorexidina a 2%, de hipoclorito de sódio a 2,5% ou soro fisiológico. Um grupo controle não recebeu preparo biomecânico. Foram realizadas culturas microbiológicas antes e após 30 dias do preparo biomecânico. Após este período os animais foram mortos para processamento e análise histopatológica. O estudo microbiológico demonstrou que houve redução dos microrganismos nos grupos que utilizaram soluções antimicrobianas (p<0,05), com melhor resultado para a solução de clorexidina. Os grupos que utilizaram solução fisiológica controle apresentaram aumento de microrganismos. No estudo histopatológico, foi observado, de um modo geral, infiltrado inflamatório periapical severo e em grande extensão, severo espessamento do ligamento periodontal e grandes áreas de reabsorção óssea e apical em todos os grupos (p>0,05). Concluiu-se que o emprego de soluções irrigadoras antimicrobianas durante o preparo biomecânico promove redução da microbiota endodôntica, sem a sua eliminação do sistema de canais radiculares em dentes de cães com lesão periapical. A solução de clorexidina a 2% proporcionou maior redução da microbiota que a solução de hipoclorito de sódio a 2,5% (p<0,05). Porém, os resultados histopatológicos demonstram que somente o preparo biomecânico não foi capaz de criar condições para reparação dos tecidos apicais e periapicais.
The aim of this study was to evaluate the microorganisms in the root canal system before and after biomechanical preparation and the apical and periapical repair after this biomechanical preparation. The study was performed in 78 root canals of dog's teeth with induced chronic periradicular lesion. There were used the following endodontic irrigating solutions: 2% chlorhexidine digluconate solution; 2.5% sodium hypochlorite solution, saline solution and a control group without biomechanical preparation. The microbiological sampling were performed before and 30 days after the biomechanical preparation. After this period the animals were killed to histological analysis. In the microbiologic study, the results showed that the antimicrobial solutions used reduced the number of microorganisms (p<0.05). The chlorhexidine solution showed better performance. The group that used saline solution and the control group presented an increased number of microorganisms. The histological results showed a severe periapical inflammation, severe thickness of periodontal ligament, apical and osseous resorption in all groups (p>0.05). It was concluded that the antimicrobial endodontic solution reduced but not eliminated the microorganisms present in root canals of dogþs teeth with necrosis and periapical lesion. The chlorhexidine solution was more effective in reducing the number of microorganisms than sodium hypochlorite solution (p<0.05). Although, the histopathological results showed that the biomechanical preparation alone was not capable to promote an adequate condition for the apical and periapical tissues repair.
Hou, Shiji [Verfasser], Paul [Gutachter] Schulze-Lefert, and Ute [Gutachter] Höcker. "Root microbiota functions in mitigating abiotic and biotic stresses in Arabidopsis / Shiji Hou ; Gutachter: Paul Schulze-Lefert, Ute Höcker." Köln : Universitäts- und Stadtbibliothek Köln, 2021. http://d-nb.info/1231992778/34.
Повний текст джерелаDombrowski, Nina [Verfasser], Paul [Akademischer Betreuer] Schulze-Lefert, Alga [Akademischer Betreuer] Zuccaro, and George [Akademischer Betreuer] Coupland. "Structural and functional analysis of the bacterial root microbiota of Arabidopsis thaliana and relative species / Nina Dombrowski. Gutachter: Paul Schulze-Lefert ; Alga Zuccaro ; George Coupland." Köln : Universitäts- und Stadtbibliothek Köln, 2015. http://d-nb.info/1071369857/34.
Повний текст джерелаLopes, Lucas Dantas. "From communities to genomes: a multifaceted approach to depict bacterial life in soils." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-02012018-141554/.
Повний текст джерелаDesvendar a ecologia microbiana do solo é essencial para aumentar a produtividade agrícola sustentável. Estudos baseados em comunidades revolucionaram esse campo nas últimas décadas, mas ainda há muito a ser revelado. Esta tese propôs uma abordagem para aumentar a resolução desses estudos, combinando sequenciamento em larga escala de rDNA 16S e genômica populacional, com o objetivo de explorar mais a fundo as diferenças apontadas por análises de comunidades, assim como superar as limitações do uso de unidades taxonômicas operacionais (UTOs) como entidades ecológicas e introduzir o pensamento evolutivo na ecologia microbiana. Nossa principal meta foi entender as características que tornam as bactérias hábeis em colonizar a rizosfera de cana-de-açúcar ou viver no solo saprofiticamente. Rizosfera e solo são hábitats contrastantes para a vida microbiana, já que são altamente distintos em suas características físicas, químicas e, consequentemente, biológicas. Nossos resultados indicaram que a cana-de-açúcar modifica o microbioma da rizosfera e o metabolismo do ácido D-galacturônico é uma função chave para colonizar este nicho. Dentre os táxons que prevalecem na rizosfera, o gênero Pseudomonas foi escolhido para um estudo mais detalhado, considerando os seus atributos de promoção de crescimento de plantas. Setenta e seis Pseudomonas spp. fluorescentes foram isoladas e submetidas ao sequenciamento do genoma. Uma análise de genômica comparativa foi realizada entre as populações obtidas do solo e rizosfera. As análises filogenéticas classificaram os isolados nos grupos P. fluorescens (57) ou P. putida (19). Doze prováveis novas espécies e dois novos subgrupos propostos de P. fluorescens foram encontrados no solo tropical prospectado. A genômica comparativa revelou que genes de fosfatases e de uso de xilose foram significativamente enriquecidos nas populações da rizosfera e solo do grupo P. fluorescens, respectivamente. O catabolismo do ácido D-galactônico foi maior na população da rizosfera do grupo P. putida, baseado tanto em resultados genotípicos quanto fenotípicos. O crescimento em D-xilose foi mais explorado usando linhagens geneticamente modificadas e confirmou que este açúcar é mais utilizado por membros da população do solo do que da rizosfera no grupo P. fluorescens, um padrão também observado no microbioma do solo. Em resumo, essas descobertas constituem um passo adiante no entendimento da ecologia bacteriana do solo e rizosfera, por superar algumas limitações de análises de comunidades e mostrar diferenças genômicas entre populações bacterianas destes hábitats.
Achemedei, Bronwyn. "Potential risk factors associated with the microbiota of grass roots in the Kimberley region of Western Australia." Thesis, Achemedei, Bronwyn (2016) Potential risk factors associated with the microbiota of grass roots in the Kimberley region of Western Australia. Honours thesis, Murdoch University, 2016. https://researchrepository.murdoch.edu.au/id/eprint/35151/.
Повний текст джерелаOurry, Morgane. "Contribution à l'analyse des interactions tripartites entre Brassica napus, Delia radicum et leur microbiote." Thesis, Rennes, Agrocampus Ouest, 2019. http://www.theses.fr/2019NSARA032.
Повний текст джерелаMicroorganisms have a strong influence on plant-insect interactions. We have studied the interaction between oilseed rape (Brassica napus), the cabbage root fly (Delia radicum) and their associated microbial communities. Soil microbial diversity was manipulated with the dilution to extinction approach to assess its effect on plant chemistry and insect life history traits. Diversity variation influenced the fly emergence rate and oviposition, but not plant chemistry. Conversely, herbivory by D. radicum strongly modified root chemistry and both root and rhizosphere microbial communities. We proposed a scenario that in the presence of herbivory, plants would produce defensive compounds but also would recruit, with attractive chemical compounds, soil microorganismsthat may maintain plant defenses. Bacterial communities of adult flies, free of their facultative symbiont Wolbachia, were studied using an antibiotic. We showed that tetracycline decreased fly bacterial diversity, without making them sterile, modified community composition, and that effect lasted over several generations. Lastly, studying bacterial transmission in D. radicum showed two species shared between females and eggs, and two others between larvae and both roots and rhizosphere. This study showed that having a better understanding of plant-insect interactions and how strongly microorganisms can influence their own host or other interacting organisms is a crucial step that could promote microbial applications in a context of insect biological control
Lima, Bruna Roese de. "Detecção microbiana e de genes de resistência em ecossistemas da cavidade oral de pacientes infantis com necrose pulpar." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/128201.
Повний текст джерелаSome studies characterized the microbiota of root canals of primary teeth with pulp necrosis as polymicrobial, with a predominance of anaerobic microorganisms. However, no study to date has investigated the presence of antimicrobial resistance genes in different ecosystems of the oral cavity of children. This study aims to determine the presence of Prevotella species and genes associated with resistance to beta-lactams in different oral enviroments of children with pulp necrosis. Twenty-seven children who were under dental care at the Children and Youth Clinic (Dental School, UFRGS, Porto Alegre, Brazil), and who had at least one primary tooth with pulp necrosis were selected for this study. Saliva, supragingival biofilm, pulp chamber biofilm and root canal biofilm were collected of 32 teeth (27 posterior and 5 anterior). After isolation of microbial DNA, the presence of Prevotella intermedia, Prevotella nigrescens, Prevotella tannerae and cfxA/cfxA2 gene were evaluated using the PCR. The sample consisted of patients with a mean age of 5.5 years (± 1.76). The total rate of Prevotella species was 29.1%, 25%, 21.8% and 32.29% in saliva samples, biofilm, pulp chamber and root canal, respectively. The three strains were not detected in all enviroments of the same patient, but were present at 3.1% (n = 1) of the root canal samples. Prevotella nigrescens was the most common bacteria in all oral enviroments. Statistical significant differences were observed for the presence of P. nigrescens at least one oral enviroment and age of the patient (t-test, p = 0.04). Also an association was observed, among the presence of these bacteria in at least one enviroment and use of antimicrobials (Fisher's exact test, p = 0.014). The presence of the resistance gene to beta-lactams, cfxA/cfxA2, was tested on 12 patients of the sample at all four oral enviroments. Among these patients, 55.6% were girls with a mean age of 6 years (± 2.5). Absence of this gene in the sample investigated was detected. The absence of cfxA/cfxA2 gene was observed in all the investigated samples. Future studies testing the presence of other resistance genes to beta-lactams, are important for a comprehensive investigation.
Pump, Judith [Verfasser], and Ralf [Akademischer Betreuer] Conrad. "Carbon translocation and methane emission in flooded rice microcosms with a manipulated root microbiome / Judith Pump. Betreuer: Ralf Conrad." Marburg : Philipps-Universität Marburg, 2013. http://d-nb.info/1035502224/34.
Повний текст джерелаReis, Luciana Carvalho. "Capacidade de selamento de três materiais retrobturadores frente à infiltração microbiana por Enterococcus faecalis." Universidade do Estado do Rio de Janeiro, 2010. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=2650.
Повний текст джерелаThe objective of this study was to compare the apical sealing ability of three root-end filling materials in teeth submitted to the microbial leakage by Enterococcus faecalis. Besides analyzing the occurrence of the microbial leakage in relation to the variable time.For such, 80 canine permanent superior teeth extracted from humans were used, which were instrumented with ProTaper Universal system (MAILLEFER) and filled by the lateral compaction technique, with two types of endodontic sealers: Endofill (DENTSPLY) and AH Plus (DENTSPLY). The apices were resected with the removal of 3mm of the apical third and the root-end cavities prepared with ultrasonic tips. The samples were subdivided, randomly, in 6 groups with 10 teeth each, and 2 control groups. The materials used for the retrofilling were white MTA (ANGELUS), IBC BioAggregate (INNOVATIVE BIOCERAMIX INC.) and Acroseal (SEPTODONT). Devices were made for fixation of the teeth to the Eppendorf tubes. The filling samples were inoculated with strains of E. faecalis and incubated at 37C, for a period of 90 days, for analysis of the presence of turbidity of Enterococcosel medium. For the accomplishment of the statistical analysis the following tests were used: Qui-square with Exact Proof of Fisher and Kruskal-Wallis. The results showed that all the groups in which the filling was accomplished and the subsequent retrofilling presented leakage. Comparing all groups, there was not significant difference among the tested materials. In regard to only the root-end filling materials, Acroseal obtained the smallest leakage, followed by white MTA and IBC BioAggregate. The samples filled with the sealer Endofill didn't present statistical difference in relation to the variable time. However, in the samples filled with the sealer AH Plus, there was larger leakage occurrence in the samples retrofilled with IBC BioAggregate and smaller leakage in the samples retrofilled with Acroseal, with statistically significant difference at a 10% level.
Paes, Fabio Resende. "Infiltração microbiana em remanescentes de obturação de canais radiculares acrescidos de selador temporário." Universidade Federal de Uberlândia, 2006. https://repositorio.ufu.br/handle/123456789/16848.
Повний текст джерелаEstudou-se a infiltração microbiana em remanescentes de obturação de canais radiculares selados com guta-percha e cimento Sealapex, utilizando ou não um tampão com material selador temporário Coltosol ou o adesivo Super-Bonder. Trinta e dois dentes unirradiculares humanos extraídos foram utilizados e distribuídos aleatoriamente em quatro grupos experimentais com 08 amostras cada, sendo um controle. Para o modelo de estudo, empregou-se uma plataforma, dividida em duas partes: câmara superior onde foi introduzida a suspensão microbiana contendo os indicadores biológicos (E. faecalis + S. aureus + P. aeruginosa + B. subtilis + C. Albicans); e, câmara inferior, com o meio de cultura Brain Heart Infusion, onde os dentes permaneceram imersos com 3mm do remanescente apical radicular durante o período de 60 dias. Os dados obtidos foram submetidos ao teste estatístico Kruskal-Wallis. Os resultados mostraram que no grupo 1 - remanescente de obturação com Sealapex + guta-percha de 5mm não foi verificado infiltração microbiana em 100% das amostras; no grupo 2 - remanescente de obturação com cimento Sealapex + guta-percha de 5mm + tampão de 1mm de Cotosol e 3 - remanescente de obturação com cimento Sealapex + guta-percha de 5mm + tampão de 1mm de Super Bonder não foi verificado infiltração microbiana em 87,5% das amostras. Não houve diferença estatística significativa entre os três grupos, quanto à infiltração microbiana, decorridos 60 dias (p<0,05).
Mestre em Odontologia
Filho, Solismar de Paiva Venzke. "Biomassa microbiana do solo sob sistema de plantio direto na região de Campos Gerais, Tibagi, PR." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/11/11138/tde-10022004-151043/.
Повний текст джерелаThe demand for information about the nutrient cycling in soils under no-tillage motivated the study about soil microbial biomass (SMB) variations in different texture soils submitted for a long period to this kind of management system. The usual sequence of crops adopted for more than 20 years in Campos Gerais, Tibagi (PR) is soybean/corn during the summer and wheat/oats during the winter. The objective was to keep track of the microbial-C and N variations during a crop rotation cycle in four areas: three of them have been cultivated for 12 years under the no-tillage system, with a clay (PD12-TmuA), a sandy clay (PD12-TA), and a sandy clay loam (PD12-TmeA) texture, and a fourth, 22 years under the no-tillage system with a sandy clay loam textural class (PD22-TA). Nine soil samplings were performed during a period of 18 months, each time collecting four soil layers (0-2,5; 2,5-5; 5-10; 10-20 cm). Several corn and soybean root parameters were also evaluated in PD22-TA to determine the influence of diverse crops (C4 and C3 plants) on the microbial biomass concentration in the soil profile. The ten-year difference in no-tillage system adoption caused and increase of microbial-C in PD22-TA in relation to PD12-TA in the deeper soil layers. The PD22-TA also showed, on average, 30,8 kg Nmic.ha -1 more microbial-N than the PD12-TA in the 0-20 cm, with a narrower range of variation. The divergence in texture among the 12-year no-till sites resulted in higher microbial-C and N means in the 0-20 cm soil layer, except for 20 days after the wheat sowing. PD12-TA and PD12-TmeA did not show significant differences in the microbial-C amounts only for the 0-5cm layer. Microbial-C was more positively correlated with N-NH4 + and N-NO3 - than microbial-N, independently of soil texture, time since no-till adoption and crop sequence. The corn root system totaled 1324 kg C ha -1 and 58 kg N ha -1 in the upper soil layer, with higher density per length and per active root dry mass, and more roots in decomposition. The soybean root system (392 kg C ha -1 and 21 kg N ha -1 ) contributed more with fine roots and density per length than the corn. The effect of the corn root system on microbial-C reached deeper soil layers than the soybean roots. Microbial-N was stimulated by fine and active root concentration and by roots in decomposition phase, probably due to higher labile C and N concentration released to the soil. It was concluded that the microbial-C increased in depth along the period of no-till adoption, while the microbial-N showed less variation in the 0-20 cm soil layer. Both microbial-C and N are influenced by soil texture, although similar textural classes under no-till can maintain similar microbial-C amounts in the 0-5 cm soil layer during the crop production system.
Guyonnet, Julien. "Effet de la stratégie de gestion des ressources des plantes sur l’investissement dans l’exsudation racinaire, et les conséquences sur les communautés bactériennes." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1008.
Повний текст джерелаRoot exudation is known to influence microbial communities functioning, in particular those involve in nitrogen cycle. (Haichar et al, 2012). It’s linked to plant physiology, which can be evaluated with functional traits, allowing a plant distribution in function of their performance in their environment. Thus, we can distinguish competitive species, with higher photosynthetic capacity and rapid rates of N acquisition, conservative species with the opposite characteristics (Aerts & Chapin, 1999) and intermediate plants, with intermediate characteristics.The objective of this work is to determinate the influence of nutrient management strategiy of 6 poaceae, along a strategies gradient from conservative strategy (Sesleria caerulea and Festuca paniculata), intermediate (Antoxanthum odoratum and Bromus erectus) to competitive strategy (Dactylis glomerata and Trisetum flavescens), on diversity and functioning of total and denitrifying communities.I) Firstly, we studied the link between the plant nutrient management strategy and the root exudates quantity in the root adhering soil (RAS). Then, we determined the influence of the rate of root exudation on potential microbial activities (respiration and denitrification), and with a DNA-SIP (Stable Isotope Probing) approach coupled to high-throughput sequencing, the influence of root exudation on the bacterial structure and diversity of communities colonizing the RAS and the root system. II) Secondly, we studied the link between the plant nutrient management strategy and the nature of molecules exuded in RAS and present in root extracts by analyzing primary metabolites profile to Festuca paniculata, Bromus erectus and Dactylis glomerata, respectively a conservative, an intermediate and a competitive plant. Then, we determined the influence of primary metabolites profile of each plant on semi-real denitrification of communities colonizing RAS of plants. III) Finally, an mRNA-SIP approach is in progress to determine the influence of exuded metabolites on active bacterial communities functioning and the expression of genes involved in denitrification process in RAS and root system. Our results show an influence of the nutrient management strategy on the rate of carbon exudation, the competitive plants exuding more than conservatives ones
Suárez, Díaz Javier. "Methodological strategies in contemporary symbiosis research and their historical roots: From mechanistic to non-mechanistic modes of explanation." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/668997.
Повний текст джерелаLa investigación sobre la simbiosis es un campo en crecimiento en la biología contemporánea. Los avances actuales en el modelado y las técnicas experimentales han permitido desarrollar nuevas maneras de estudiar algunos sistemas simbióticos de múltiples especies cuyo estudio había sido ignorado en el pasado. Algunas de estas nuevas técnicas experimentales y de modelado se basan en el uso de herramientas matemáticas sofisticadas (como el análisis de redes) que solo se pueden emplear si el sistema se concibe de manera holística. Una de las principales consecuencias de este enfoque es que la descomposición del sistema en partes se vuelve una tarea imposible: si los biólogos quieren comprender cómo funcionan algunos sistemas simbióticos de múltiples especies, cómo se comportan o cómo evolucionan, deben estudiar el sistema de manera holística, en lugar de estudiar cómo cada una de las partes del sistema se relaciona entre sí. Este tipo de investigación parece cuestionar la tradición dominante en la filosofía contemporánea de la ciencia y la biología, a saber: el nuevo mecanismo. De acuerdo con los principios de la filosofía del nuevo mecanicismo, los sistemas biológicos deben descomponerse en sus elementos componentes para comprender adecuadamente cómo funcionan y para descubrir las conexiones causales entre los mismos. El propósito de esta tesis doctoral es comprender cómo la investigación contemporánea sobre simbiosis cuestiona algunas de las tesis filosóficas centrales que subyacen a la filosofía del nuevo mecanismo. Para hacerlo, la tesis se basará en dos métodos filosóficos: (1) análisis de la práctica científica; (2) análisis conceptual. Al aplicar estos dos métodos a la investigación contemporánea sobre simbiosis, la tesis da lugar a tres artículos en revistas especializadas, que se agregan como anexos. La contribución original clave de la disertación doctoral es que la investigación contemporánea sobre la simbiosis se basa en el uso de ciertos métodos matemáticos que solo son aplicables si el sistema se estudia de manera holística y, por lo tanto, conlleva una forma de explicación no mecanicista y no causal. Al final, se presentan varias preguntas abiertas para futuras investigaciones.
Lusley, Pauline. "Compréhension des mécanismes directs et indirects de résistance à la pourriture racinaire du pois causée par Aphanomyces euteiches : influence du choix variétal et de la cohorte microbienne associée. Compared analysis of architectural symptoms and disease severity caused by Aphanomyces euteiches between winter and spring peas. Co-existence of Rhizobia and non-rhizobial bacteria in the nodules of Pisum sativum L. depending on cultivars and influencing mycelium growth of Aphanomyces euteiches. The microbial cavalry: how crop could be determinant to beneficially shape soil microbiome in the battlefield against Aphanomyces euteiches." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR091.
Повний текст джерелаPea, well-adapted to the Normandy pedoclimatic context, represents an important nutritional source of plant proteins. At present, protein crops are among the promoting crops in view of their many agronomical, economic, and environmental interests. Despite their multiple advantages, the cultivation of protein peas is not as successful, mainly due to strong attacks by various phytopathology. The most damaging is pea root rot caused by Aphanomyces euteiches leading to a significant drop in yield and thus can penalize farmers. As there is no effective treatment to date, numerous focus researches are in progress to develop efficient control methods, which requires a holistic understanding of the pathobiome. In this thesis, studies were focused on the understanding of some direct and indirect resistance mechanisms of pea root rot caused by A. euteiches. The contribution of biotic factors in this disease were studied, specifically the influence of varietal genotype and its associated phytobiome, and so the establishment of multiple interactions with microorganisms. The comparative analysis of disease severity and induced architectural modifications, showed a differential expression according to their affiliation to winter or spring group. The two winter pea cultivars characterized by a high cold tolerance presented two features of interest: a delayed impact on aerial part despite significant root damage and an increased growth of root system in response to infection. In addition, the study of intra-nodule bacterial diversity in these same cultivars showed that the diversity of their nodule microbiome varies according to varietal genotype. This study highlighted the strong biocontrol potential of intra-nodule bacterial endophytes, with a higher relative abundance of known antagonistic bacterial genera towards A. euteiches for two winter pea cultivars. The varietal genotype therefore constitutes a direct and indirect lever by the establishment of interactions with beneficial microorganisms, to fight against pea root rot. The last research line has demonstrated the strong influence of plant cultivated species on the microbial associations in the rhizosphere, specifically a modulation of the assemblage of beneficial populations. Shaping the microbial community composition though the cultivation of crops to the benefit of the next crop represents an additional argument in favor of crop rotation use as a lever against phytopathology. Several interesting alternatives were highlighted in this research work to effectively and efficiently manage A. euteiches: at the cultivar scale, by specific characteristics in relation to varieties’ genotype and their ability to select protective endophytes, and at the scale of crop rotation, by shaping microbiome in favor of pea. Great research perspectives are emerging, especially the efficiency of protection resulting from all potential isolated biocontrol agents, which would allow the development and implementation of beneficial consortia adapted to Normandy soils and to pea cultivars specificities
Yang, Luhua [Verfasser], Michael [Akademischer Betreuer] Schloter, Caroline [Gutachter] Gutjahr, and Michael [Gutachter] Schloter. "The role of the seed microbiome of barley (Hordeum vulgare) as driver for the composition of root endophytes / Luhua Yang ; Gutachter: Caroline Gutjahr, Michael Schloter ; Betreuer: Michael Schloter." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/1215293399/34.
Повний текст джерелаAndrade, Laíse de Oliveira. "Métodos rápidos para identificação microbiana aplicados ao monitoramento ambiental de salas limpas: ênfase na tecnologia MALDI-TOF." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/9/9139/tde-26102017-114152/.
Повний текст джерелаMatrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been increasingly introduced in routine microbiological identifications of pharmaceutical quality control laboratories, mainly for the activities of the Environmental Monitoring Program of Clean Rooms. The long time needed to obtain the results through conventional methods has stimulated the search for techniques that allow rapid methods, as MALDI-TOF MS. Thus, the objective of this work was to evaluate the suitability of the MALDI-TOF MS technique for the identification of bacteria isolated from the environment of clean rooms used in some stages of the production of a viral vaccine. Thirteen bacterial species commonly isolated from clean rooms studied and five strains ATCC were identified by MALDI-TOF MS technique and by a biochemical technique (BBL Crystal® System). Performance of MALDI-TOF MS was better than biochemical technique for correct species identifications (88.89% and 38.89%, respectively) and produced fewer unreliable identifications (5.55% and 22.22%, respectively). MALDI-TOF MS can be implemented for routine identification of bacteria in a pharmaceutical quality control laboratory. However, as a database-dependent system, maybe some isolated not identified by this technique must be additionally studied and, if appropriate, added to an in-house database.
Raveau, Robin. "Contribution au développement d’une filière éco-innovante de phytomanagement de sols pollués par les éléments traces : culture de plantes aromatiques et production d’huiles essentielles The Aromatic Plant Clary Sage Shaped Bacterial Communities in the Roots and in the Trace Element-Contaminated Soil More Than Mycorrhizal Inoculation – A Two-Year Monitoring Field Trial." Thesis, Littoral, 2020. http://www.theses.fr/2020DUNK0580.
Повний текст джерелаTo cope with the soil trace element (TE) pollution, phytomanagement was brought forward as an eco-friendly and feasible approach. To meet the dual requirements of environmental and economic performances, phytotechnologies are now combined with the valorisarion of biomass produced on polluted soils. Among the eco-innovative channels intended for the non-food valorisation of the produced biomass, the cultivation of aromatic and medicinal plants producing essential oils (EO), high-added value biosourced products, has been suggested within the framework of PhytEO project, funded by ADEME. Thus, this thesis contributed to evaluate the relevance of a management approach based on clary sage and coriander cultivation, combined or not with a mycorrhizal inoculum, on in situ experimental plots polluted or not with TE. Both clary sage and coriander have shown a good ability to settle in, to grow and to produce high amounts of biomass, despite the presence of high TE concentrations in the soil. The addition of an amendment based on arbuscular mycorrhizal fungi enhanced the mycorrhizal colonisation rates of both coriander and clary sage roots. However, no significant improvement was observed in terms of plants’ growth, EO amounts and quality. Moreover, mycorrhizal inoculation allowed TE immobilisation in soils, in particular Pb, and reduced TE (Cd and Pb) transfers in aerial parts of clary sage. Besides, the EO distilled from clary sage inflorescences and coriander (aerial parts orseeds) grown on TE polluted soils, displayed a highly satisfactory quality, regarding the absence of contamination by TE or pesticide residues (trace amounts). Their chemical compositions were not altered by both TE pollution and mycorrhizal inoculation and were characterized by several active principles, such as linalool, linalyl acetate, germacrene, α-pinene, γ-terpinene, 2-decenal, decanal and 2-dodecenal. Furthermore, several biological properties with potential applications in non-food fields such as crop protection (antifungal, antigerminative and herbicidal) or human healthcare (antioxidant and anti-inflammatory) have been brought forward. However, despite its ability to form inclusion complexes with EO components, β-cyclodextrin has shown no significant improvement of the tested EO biological activities. On another note, the soil revegetation with clary sage displayed a clear shaping of the bacterial and fungal communities, in both the rhizospheric soil and the roots of the aromatic plant species. Altogether, our results combined with the techno-economic feasibility assessment of the channel “aromatic and medicinal plants/EO” have emphasised clary sage as a good candidate for the phytomanagement of TE-polluted soils
Delgado, Ronan Jacques Rezende. "Avaliação in vitro da viabilidade de Enterococcus faecalis e Candida albicans nos túbulos dentinários após a aplicação de hidróxido de cálcio e clorexidina gel 2%." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/25/25138/tde-18102007-155525/.
Повний текст джерелаA pulp infection can result in a microbial colonization of the entire root canals system, including dentinal tubules. These microorganisms and their toxic product are responsible for the development and persistence of apical periondontitis from endodontic source. The present study aimed to evaluate E. faecalis and C. albicans viability in dentinal tubules after the application of calcium hydroxide, chlorhexidine gel 2%, calcium hydroxide associated to chlorhexidine gel 2% and physiological solution, through the analysis by microbiological culture and fluorescence microscopy. For that, 120 human teeth root were standardized and submitted to autoclave, and after ere divided into 2 groups (n=60) for E. faecalis and C. albicans contamination for 21 days. Following this, they were divided into 8 groups (n=15) for application of antimicrobial substances in the root canals and subsequent incubation for 14 days. Samples from root dentin with 0 - 100 µm and 100 - 200 µm of extension were collected and submitted to microbiological culture.After 48 hours of incubation, it was performed the evaluation of colony-forming units (CFU). At the same time, the samples were processed for fluorescence microscopic analysis with the assistance of specific fluorescent markers, in order to determine the proportion of viable and non-viable microorganisms. Other 6 specimens were prepared for the analysis of scanning electron microscopy. Results demonstrated a higher capacity of penetration in the tubules for E. faecalis than for C. albicans. The application of intracanal medication resulted in significant reduction of microorganisms viability when compared to the control groups independently of the medication used and in both evaluated portions of root dentin. However, when one compares individually the medications, it was observed a better performance of chlorhexidine gel 2% and the association of calcium hydroxide with chlorhexidine gel 2% without a significant difference between them. Calcium hydroxide had the worst results for disinfection of root canal contaminated with E. faecalis and C. albicans. These findings were confirmed for the microbiological culture as well as for the fluorescence microscopy. The microbiological culture and the fluorescence microscopy are adequate methods and complementary for the evaluation of E. faecalis and C. albicans viability and the efficacy of chlorhexidine gel 2% and the association of calcium hydroxide with chlorhexidine gel 2% warrant their use in Endodontics as an intracanal medication.
Rosa, Victoria Christina Scarano Figueira Paes. "Eficácia dos sistemas rotatórios e reciprocantes na redução microbiana - revisão narrativa." Master's thesis, 2020. http://hdl.handle.net/10284/9385.
Повний текст джерелаAs microorganisms are the main factor of failure during the endodontic treatment, a preponderant aspect for an efficient treatment is to provide a maximum microbial reduction of the root canal. The different systems of instrumentation in Endodontics have always been evolving with the purpose of providing to the patient as to the professional a faster, safer and more effective treatment. This work aims to analyze and compare some of the rotational and reciprocating systems available in the market, with the intention of defining which of them allows a greater reduction in the number of microorganisms in the root canal and consequently, allows to obtain a better endodontic treatment. Although all the systems studied presented similar efficiency in microbial reduction, some studies showed relevant differences in the preparation of the root canal. This makes it necessary to carry out new studies to evaluate the different systems available in the market and their respective efficiency in microbial reduction.
Whatley, Jenny J. (Jenny Johnson) 1982. "An in-vitro evaluation on the biocompatibility of resilon by the microbiota of the infected root canal utilizing an agar disc diffusion assay." Thesis, 2012. http://hdl.handle.net/1805/3093.
Повний текст джерелаResilon is a resin-based obturation material that claims to create a monoblock through bonding of RealSeal sealer to the dentin walls and to the core material. Resilon is comprised of a biodegradable polymer, polycaprolactone, and inorganic fillers. Resilon has been shown to undergo enzymatic hydrolysis by bacterial enzymes such as lipase. This study aims to demonstrate if bacteria found within the infected root canal system are capable of degrading Resilon utilizing an agar disc hydrolysis method. A 0.1-percent Resilon emulsion and a gutta-percha emulsion were prepared with Tryptic Soy Agar in plates. Several bacterial species were inoculated in eight spots each on the Resilon and gutta-percha agar plates and the plates were observed for the formation of hydrolytic halos surrounding bacteria signifying their ability to degrade the material. The bacterial enzyme Lipase PS served as a positive control. P. intermedia, P. aeruginosa, P. assacharoylitica, S. epidermidis and S. aureus all demonstrated hydrolytic halos, clear zones, at each of the eight inoculation locations (100%, 95%CI 63%-100%) on the Resilon plates. The halos were similar to those seen in the positive lipase control. No halos were seen with E. faecalis, F. nucleatum, S. mutans, S. sanguis, or P. gingivalis at any of the eight inoculation spots (0%, 95%CI 0%-37%) on the Resilon plates. No hydrolytic halos were seen around any bacterial colonies or the Lipase PS on the gutta-percha plates. The results of this study indicate that bacteria found in endodontic infections can hydrolize Resilon dispersed into an emulsion. The potential exists for Resilon degradation after its use as an obturation material in infected root canal systems. Given that root canal therapy does not render a canal void of microorganisms, it is prudent to obturate the root canal system with a material that cannot be degraded by bacteria and their enzymes.
Johnston, Monje David Morris. "MICROBIAL ECOLOGY OF ENDOPHYTIC BACTERIA IN ZEA SPECIES AS INFLUENCED BY PLANT GENOTYPE, SEED ORIGIN, AND SOIL ENVIRONMENT." Thesis, 2011. http://hdl.handle.net/10214/2747.
Повний текст джерелаOMAFRA New Directions, Ontario Research Fund, Canadian Foundation for Innovation
Noortje, Notenbaert. "The effect of selective breeding and genetic manipulation on the microbiome surrounding maize roots." Thesis, 2018. http://hdl.handle.net/2097/38860.
Повний текст джерелаDepartment of Agronomy
Charles W. Rice
Maize (Zea mays L.) is a major staple crop whose wild ancestor was domesticated about 9,000 years ago (Beadle, 1939). Long-term breeding for more desirable traits ultimately resulted in the maize we see today. This long-term breeding likely impacted the processes within the rhizosphere of maize, however, to what extent is not well understood. This study examined the microbial communities between an inbred maize line (B73), a hybrid of two isogenic lines (B73xMo17), and two genetically modified maize hybrids (DKC63-55RIB and DKC64-69RIB) to determine if the plant’s ability to attract beneficial microbes changed with breeding. The hypothesis was that the isogenic cultivar forms better relationships with bacteria and fungi compared to the newer cultivars, especially in low P soil. It was also expected that the greater the difference between the cultivars the more distinct their soil microbiome. To test these hypotheses, experiments were conducted under greenhouse and field conditions. Analyses consisted of root staining to test symbiotic relationships, phospholipid fatty acid analysis (PLFA) for microbial communities, total plant and root biomass, and nutrient content to understand plant responses. Based on the field results, there was no impact on root and shoot biomass and nutrient content by differences in cultivar. Differences in cultivar did impact arbuscular mycorrhizal fungi (AMF) colonization, which decreased over time and depth for all. Soil AMF also saw a significant effect by cultivar. Other microbial groups were not impacted by cultivar, were greatest in the control, and decreased over time. Greenhouse results showed a cultivar by time interaction for root and shoot biomass. Soil P also impacted shoot biomass, but not root biomass. Shoot nutrient content was greater in high P soil, while roots only saw an impact for root P. No cultivar effect was found for soil microbial groups except for fungi, while all microbial groups were reduced in the control soil. Most soil microbial groups were also impacted by soil P as indicated by reduced concentrations in low P soil. AMF was the only microbial group that was not negatively impacted by limited soil P. In addition, all soil microbial groups increased over time, although fungi saw a decrease at R1. No significances were observed for percent AMF colonization.
Véliz, Vallejos Debora Fabiola. "The effect of quorum sensing signals on nodulation of Medicago truncatula." Phd thesis, 2016. http://hdl.handle.net/1885/111187.
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