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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Determining the Polymicrobial Relationship Between Candida albicans and Enterobacter spp

Cornett, Abigail 07 April 2022 (has links)
Candida albicans is the most common human fungal pathogen. Its relationship with various bacterial species has been documented, showing an increase in host mortality in some cases and a decrease in others. The need for new antibiotics and antifungal treatments have led to studies on polymicrobial interactions and how those interactions impact host health. Interactions between microbes within the human body are inevitable, and exploring these relationships can aid in the development of novel antimicrobials and can deepen our understanding of the complex human microbiome. The relationship between C. albicans and Enterobacter bacteria have yet to be explored. Both are commensal organisms, living asymptomatically in immunocompetent individuals. The hypothesis of this study is that C. albicans and both E. aerogenes and E. cloacae have a positive relationship and work together to infect the host. In this study, the physical cell-to-cell interaction was analyzed by utilizing planktonic (free-floating) and biofilm co-cultures, performing live/dead staining, observing the effect of morphology on the interaction, and examining if Enterobacter alters C. albicans morphology. C. albicans was cultured with Enterobacter lysate to determine if Enterobacter can inhibit C. albicans without physical contact. Enzyme-linked immune assays (ELISAs) were performed on C. albicans ALS deficient mutants to ascertain their potential involvement in cell-to-cell adherence. ELISAs were also utilized to screen E. cloacae mutants for deficiency in attachment to C. albicans. Reverse transcriptase polymerase chain reaction (RT-PCR) was performed to compare expression of the HWP1 gene in C. albicans when mono-cultured versus co-cultured. Caenorhabditis elegans were used as a host model to examine the effect that co-culture has on survival and microbial burden. It was found that Enterobacter can inhibit C. albicans growth, no matter its morphology, and it is not necessary for Enterobacter cells to be present for inhibition to occur. C. albicans appears to have more hyphae when incubated with Enterobacter for 24 hours than incubated alone. Research involving ELISAs, RT-PCR, and C. elegans is ongoing.
62

The antibiogram as an aid in the identification of the Klebsiella-enterobacter-serratia group

Hall, Richard Keith 01 January 1976 (has links)
The purpose of this study was to examine and evaluate the K-E-S group from this community with respect to distribution in clinical materials, detailed individual biochemical characteristics, and antibiogram patterns using the Bauer-Kirby disc technique, and compare these findings with those of other investigators from other geographic locations. As far as can be determined, this is the only study of its kind on the West Coast of the United States.
63

Identification of a Possible Selenite Sensor Protein from <i>Enterobacter</i> sp. YSU

Rono, Beatrice C. 23 September 2013 (has links)
No description available.
64

Characterizing Enterobacter cloacae Genetic Elements Responsible for Interactions with Candida albicans

Suarez, Abigail 01 August 2024 (has links) (PDF)
Polymicrobial interactions are an important, yet understudied area of research. Candida albicans is the most common human fungal pathogen. The bacterial genus, Enterobacter, is a source of nosocomial acquired infections and increased drug resistance. Our lab has previously discovered that Enterobacter preferentially adheres to C. albicans hyphae. From an E. cloacae transposon library screen, six candidates displayed reduction in C. albicans attachment. These candidates were identified genetically and characterized for involvement in attachment to C. albicans. A fluorescent plasmid was introduced into E. cloacae to measure and observe adherence to C. albicans in planktonic and biofilm growth. In vivo experiments using Caenorhabditis elegans showed no significant differences in microbial burden or nematode survivability exposed to Candida and Enterobacter. Candida-Enterobacter co-infections were observed microscopically within C. elegans. This study highlights the complex dynamics of C. albicans-E. cloacae interactions, underscoring the importance of understanding polymicrobial relationships in research and clinical settings.
65

A study of the effect of dilution rate on bacterial populations

Edwards, H. Randall January 1965 (has links)
Population levels of a mixed culture that was ambiently exposed to bacteria in the atmosphere was studied at various constant dilution rates. Random fluctuations in the free swimmer population were noted. An aseptic continuous flow system proved of no great advantage over that which had ambient inoculation, however, slime production did not follow identical growth patterns in three identical growth vessels. Coulter counts were made on a pure culture of B. cereus grown in a continuous flow system at various dilution rates. These counts did not follow continuous flow theory for a pure culture in that there was no sharp drop in count at the critical dilution rate but gradual reductions over a range of several dilution rates. Total population counts by the Coulter Counter were made on a defined mixed culture of B. cereus and A. aerogenes. After a several days Petroff-Hausser counts showed that 70% of the population was A. aerogenes. Total population was reduced from that of a pure culture of B. cereus. Steady-state populations were noted at various dilution rates. These steady-states, however, did not follow continuous flow theory for a pure culture in that larger counts were noted at a higher dilution rate than some counts at a lower dilution rate. It seemed that slime on the growth vessels’ walls continually changed the environment had a greater effect and made it impossible to control all the environmental factors even in continuous flow processes. / Master of Science
66

Interações entre calos de cana-de-açucar e bactérias diazotróficas endofíticas isoladas de cana-de-açúcar. / Interactions between sugarcane callus and endophytic bacteria diazothrophic isolated from sugarcane.

Carvalho, Adriana Macedo de 06 May 2013 (has links)
A cana-de-açúcar tem elevada importância econômica e agrícola. Bactérias diazotróficas possuem importante papel nos níveis de nitrogênio combinado no solo. Tornando estas bactérias as maiores fontes naturais de nitrogênio reduzido. Os gêneros bacterianos escolhidos são endofíticos, diazotróficos, isolados de cana-de-açúcar. Utilizou-se células de cana-de-açúcar na forma de calo como um modelo da interação bactéria-planta. Os experimentos com misturas bacterianas, avaliaram se dois gêneros seriam capazes de interagir, e nas contribuições às células vegetais. Pseudomonas sp. e Pantoea sp., sofreram inibição do crescimento e Enterobacter sp. foi estimulado. Pseudomonas sp. mostrou ser uma fraca competidora. Quando associadas, a morte de Pseudomonas sp. foi estimulada por Pantoea sp.. Os efeitos do calo na nitrogenase foram observados pontualmente e os no crescimento por períodos maiores. Conteúdos de EROs auxiliaram nos resultados de patogenicidade das linhagens. / The sugarcane has a high economic and agricultural importance. Diazotrophs play an important role in combined nitrogen levels in the soil. Making these bacteria the highest natural sources of reduced nitrogen. The bacterial genera chosen were endophytic diazotroph isolated from sugarcane. Was used cell sugarcane in the form callus as a template of the bacteria-plant interaction. The experiments with bacterial mixtures, evaluated whether two genres would be able to interact, and contributions to plant cells. Pseudomonas sp. and Pantoea sp. suffered growth inhibition and Enterobacter sp. was stimulated. Pseudomonas sp. proved to be a weak competitor. When attached, the death of Pseudomonas sp. was stimulated by Pantoea sp .. The effects of nitrogenase were observed in callus punctually and growth for longer periods. Contents of ROS helped for the pathogenicity of strains.
67

Interações entre calos de cana-de-açucar e bactérias diazotróficas endofíticas isoladas de cana-de-açúcar. / Interactions between sugarcane callus and endophytic bacteria diazothrophic isolated from sugarcane.

Adriana Macedo de Carvalho 06 May 2013 (has links)
A cana-de-açúcar tem elevada importância econômica e agrícola. Bactérias diazotróficas possuem importante papel nos níveis de nitrogênio combinado no solo. Tornando estas bactérias as maiores fontes naturais de nitrogênio reduzido. Os gêneros bacterianos escolhidos são endofíticos, diazotróficos, isolados de cana-de-açúcar. Utilizou-se células de cana-de-açúcar na forma de calo como um modelo da interação bactéria-planta. Os experimentos com misturas bacterianas, avaliaram se dois gêneros seriam capazes de interagir, e nas contribuições às células vegetais. Pseudomonas sp. e Pantoea sp., sofreram inibição do crescimento e Enterobacter sp. foi estimulado. Pseudomonas sp. mostrou ser uma fraca competidora. Quando associadas, a morte de Pseudomonas sp. foi estimulada por Pantoea sp.. Os efeitos do calo na nitrogenase foram observados pontualmente e os no crescimento por períodos maiores. Conteúdos de EROs auxiliaram nos resultados de patogenicidade das linhagens. / The sugarcane has a high economic and agricultural importance. Diazotrophs play an important role in combined nitrogen levels in the soil. Making these bacteria the highest natural sources of reduced nitrogen. The bacterial genera chosen were endophytic diazotroph isolated from sugarcane. Was used cell sugarcane in the form callus as a template of the bacteria-plant interaction. The experiments with bacterial mixtures, evaluated whether two genres would be able to interact, and contributions to plant cells. Pseudomonas sp. and Pantoea sp. suffered growth inhibition and Enterobacter sp. was stimulated. Pseudomonas sp. proved to be a weak competitor. When attached, the death of Pseudomonas sp. was stimulated by Pantoea sp .. The effects of nitrogenase were observed in callus punctually and growth for longer periods. Contents of ROS helped for the pathogenicity of strains.
68

Diversidade da comunidade bacteriana endofítica de sementes de soja e o seu potencial biotecnológico / Endophytic bacterial community diversity of soybean seeds and its biotechnological potential

Assumpção, Laura de Castro 19 January 2009 (has links)
Tecidos vegetais, incluindo as sementes, são habitados por microrganismos denominados endofíticos, cuja interação com a planta pode conferir características vantajosas ao hospedeiro. Sabe-se que o crescimento de plantas é influenciado por fatores como a síntese de ácido-indolacético (AIA), solubilização de fosfato, fixação de nitrogênio e controle de fungos fitopatogênicos. Antes da comercialização, as condições de armazenamento de sementes de soja podem restringir o desenvolvimento de microrganismos devido à baixa temperatura e umidade. Esse fato leva ao interesse de exploração de microrganismos endofíticos resistentes a essas condições. O estudo e a caracterização dessas comunidades são de grande interesse agronômico e biotecnológico, sendo possível sua aplicação em sementes, introduzindo no campo plantas com superior potencial de produção. Com os objetivos de comparar a comunidade bacteriana endofítica de sementes de soja geneticamente modificadas e convencionais; e de isolar e caracterizar essas comunidades, sementes de 12 cultivares de soja foram amostradas, de onde 3504 isolados bacterianos foram obtidos. Os isolados foram agrupados morfologicamente de acordo com a coloração e taxa de crescimento das colônias, sendo representantes de cada grupo morfológico (no total 176 isolados) agrupados pela técnica de ARDRA (Análise de Restrição de DNA Ribossomal Amplificado). Um total de 12 ribotipos foi observado compondo a comunidade cultivada de bactérias endofíticas de sementes de soja. Representantes destes ribotipos tiveram seus genes 16S rDNA parcialmente sequenciados, identificando os integrantes desta comunidade como: Acinetobacter sp., Bacillus sp., Brevibacterium sp., Chryseobacterium sp., Citrobacter sp., Curtobacterium sp., Enterobacter sp., Methylobacterium sp., Microbacterium sp., Micromonospora sp., Pantoea sp., Paenibacillus sp., Pseudomonas sp., Ochrobactrum sp., Streptomyces sp. e Tsukamurella sp. A comunidade bacteriana endofítica de sementes de soja provenientes de plantas genticamente modificadas apresentou uma diversidade maior comparada à comunidade bacteriana de plantas convencionais. Em relação ao potencial biotecnológico desta comunidade, os resultados demonstraram que os isolados foram capazes de controlar o crescimento de fungos fitopatogênicos por antagonismo (18%), sintetizar AIA (100%), solubilizar fosfato (39%) e fixar nitrogênio (18%). Os isolados com os melhores resultados nas análises in vitro foram inoculados em sementes de soja e avaliados em casa de vegetação quanto à habilidade de promover o crescimento das plantas. As plantas apresentaram diferentes respostas à inoculação das bactérias. A maior parte dos tratamentos mostrou influência negativa das bactéria nas plantas, enquanto que um isolado de Enterobacter sp. aumentou a massa da matéria seca de raiz. Mesmo não diferindo estatisticamente, alguns isolados mostraram tendência de aumento e outros de diminuição de biomassa da planta. / Plant tissues, including seeds, are inhabited by microorganisms called endophytes, whose interaction with the plant can offer advantages to the host. It is known that plants growth promotion is induced by indole acetic acid (IAA) synthesis, phosphate solubilization and nitrogen fixation, among others. The control of phytopathogenic fungi is also related to a good plant development. Before commercialization, the seed storage conditions can restrict the development of microorganism, due to the low temperature and humidity. This fact leads to the interest of exploring resistant microorganisms to those conditions. The study and the characterization of these communities are of great agronomic and biotechnological interest, being possible its application onto seeds, introducing in the field plants with a greater production potential. In this context, the aim of this study was to isolate and identify the endophytic bacteria community in soybean seeds and study the capacity of these isolates to promote growth in the host plant, including: phosphate solubilization, nitrogen fixation, IAA synthesize and antagonism against phytopathogenic fungi. From seeds of 12 cultivars, 3504 bacteria were isolated. The isolates were morphologically grouped according to the coloration and growth rate of the colony. Representatives of each morph group, totalizing 176, were analyzed using the Amplified Ribosomal Restriction Analysis (ARDRA) technique. A total of 12 ARDRA ribotypes were observed in the cultivable endophytic community of soybean seeds. Representatives of each ribotype had their 16S rDNA gene partially sequenced, allowing to the identification of the members of this community as: Acinetobacter sp., Bacillus sp., Brevibacterium sp., Chryseobacterium sp., Citrobacter sp., Curtobacterium sp., Enterobacter sp., Methylobacterium sp., Microbacterium sp., Micromonospora sp., Pantoea sp., Paenibacillus sp., Pseudomonas sp., Ochrobactrum sp., Streptomyces sp. and Tsukamurella sp. The endophytic bacterial community of soybean seeds from genetically modified plants showed a greater diversity compared to the bacterial community of conventional seeds. In relation to the biotechnological potential of the community, the outcomes demonstrate that the isolates were able to antagonist phytopathogenic fungi (18%), synthesize IAA (100%), solubilize phosphate (39%) and fix nitrogen (18%). The isolates with best in vitro outcomes were inoculated onto seeds and tested in greenhouse for their ability to promote growth in soybean. The plants answered differently to the inoculation of each bacterial isolate. The major part of the treatments demonstrated a negative influence of bacteria onto plants, while one Enterobacter sp. isolate increased the dry mass weight of roots. Even not differing statistically, some isolates showed a tendency to increase, meanwhile others to decrease the biomass of the plant.
69

Disinfection of bacteria by photocatalytic oxidation.

January 2006 (has links)
Wong Man Yung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 106-120). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.vi / List of Figures --- p.xi / List of Plates --- p.xiii / List of Tables --- p.xv / Abbreviations --- p.xvi / Equations --- p.xviii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Water disinfection --- p.1 / Chapter 1.2 --- Bacterial species --- p.2 / Chapter 1.2.1 --- Staphylococcus saprophyticus --- p.2 / Chapter 1.2.2 --- Enterobacter cloacae --- p.3 / Chapter 1.3 --- Disinfection methods --- p.4 / Chapter 1.3.1 --- Physical methods --- p.4 / Chapter 1.3.1.1 --- UV-C irradiation --- p.4 / Chapter 1.3.1.2 --- Solar disinfection --- p.5 / Chapter 1.3.2 --- Chemical methods --- p.6 / Chapter 1.3.2.1 --- Chlorination --- p.6 / Chapter 1.3.2.2 --- Ozonation --- p.7 / Chapter 1.3.2.3 --- Mixed disinfectants --- p.8 / Chapter 1.3.3 --- Other disinfection methods --- p.8 / Chapter 1.4 --- Advanced oxidation processes (AOPs) --- p.9 / Chapter 1.5 --- Photocatalytic oxidation (PCO) --- p.10 / Chapter 1.5.1 --- PCO process --- p.12 / Chapter 1.5.2 --- Photocatalysts --- p.14 / Chapter 1.5.2.1 --- Titanium dioxide (P25) --- p.15 / Chapter 1.5.2.2 --- Silver sensitized P25 (Ag/P25) --- p.16 / Chapter 1.5.2.3 --- Silicon dioxide doped titanium dioxide (SiO2-TiO2) --- p.17 / Chapter 1.5.2.4 --- Copper(I) oxide sensitized P25 (Cu2O/P25) --- p.18 / Chapter 1.5.3 --- Irradiation sources --- p.19 / Chapter 1.5.4 --- PCO disinfection mechanisms --- p.20 / Chapter 1.6 --- Bacterial defense mechanisms against oxidative stress --- p.22 / Chapter 2. --- Objectives --- p.25 / Chapter 3. --- Materials and Methods --- p.26 / Chapter 3.1 --- Chemicals --- p.26 / Chapter 3.2 --- Bacterial culture --- p.26 / Chapter 3.3 --- Photocatalytic reactor --- p.27 / Chapter 3.4 --- PCO efficacy test --- p.30 / Chapter 3.5 --- Optimization of PCO conditions --- p.31 / Chapter 3.5.1 --- Effect of P25 concentrations --- p.31 / Chapter 3.5.2 --- Effect of UV intensities --- p.32 / Chapter 3.5.3 --- Combinational study of P25 concentrations and UV intensities --- p.32 / Chapter 3.5.4 --- Effect of stirring rates --- p.32 / Chapter 3.5.5 --- Effect of initial cell concentrations --- p.33 / Chapter 3.6 --- PCO disinfection using different photocatalysts --- p.33 / Chapter 3.6.1 --- Effect of CU2O/P25 concentrations --- p.33 / Chapter 3.6.2 --- Effect of CU2O powder on the two bacterial species --- p.33 / Chapter 3.7 --- Transmission electron microscopy (TEM) --- p.34 / Chapter 3.8 --- Catalase (CAT) test --- p.37 / Chapter 3.9 --- Superoxide dismutase (SOD) activity assay --- p.39 / Chapter 4. --- Results --- p.40 / Chapter 4.1 --- Efficacy test --- p.40 / Chapter 4.2 --- PCO disinfection under UV irradiation --- p.40 / Chapter 4.2.1 --- Control experiments --- p.40 / Chapter 4.2.2 --- Optimization of PCO conditions using P25 as a photocatalyst --- p.42 / Chapter 4.2.2.1 --- Effect of P25 concentrations --- p.42 / Chapter 4.2.2.2 --- Effect of UV intensities --- p.45 / Chapter 4.2.2.3 --- Combinational study of P25 concentrations and UV intensities --- p.48 / Chapter 4.2.2.4 --- Effect of stirring rates --- p.54 / Chapter 4.2.2.5 --- Effect of initial cell concentrations --- p.57 / Chapter 4.2.3 --- Comparison of PCO inactivation efficiency between S. saprophyticus and E. cloacae --- p.60 / Chapter 4.2.4 --- PCO disinfection using different photocatalysts --- p.62 / Chapter 4.2.4.1 --- Control experiments --- p.62 / Chapter 4.2.4.2 --- Ag/P25 --- p.62 / Chapter 4.2.4.3 --- SiO2-TiO2 --- p.64 / Chapter 4.2.4.4 --- Cu2O/P25 --- p.64 / Chapter 4.3 --- PCO disinfection under visible light irradiation --- p.66 / Chapter 4.3.1 --- Effect of Cu2O/P25 concentrations --- p.67 / Chapter 4.3.2 --- Effect of CU2O powder on the two bacterial species --- p.70 / Chapter 4.4 --- Feasibility use of indoor light (fluorescent lamps) for PCO disinfection --- p.71 / Chapter 4.5 --- Transmission electron microscopy (TEM) --- p.74 / Chapter 4.5.1 --- Morphological changes induced by PCO using P25 as a photocatalyst --- p.74 / Chapter 4.5.2 --- Morphological changes induced by PCO using Cu2O/P25 as a photocatalyst --- p.77 / Chapter 4.6 --- Catalase (CAT) test --- p.80 / Chapter 4.7 --- Superoxide dismutase (SOD) activity assay --- p.82 / Chapter 5. --- Discussion --- p.83 / Chapter 5.1 --- Efficacy test --- p.83 / Chapter 5.2 --- PCO disinfection under UV irradiation --- p.83 / Chapter 5.2.1 --- Optimization study --- p.84 / Chapter 5.2.1.1 --- Effect of P25 concentrations --- p.84 / Chapter 5.2.1.2 --- Effect of UV intensities --- p.85 / Chapter 5.2.1.3 --- Combinational study of P25 concentrations and UV intensities --- p.86 / Chapter 5.2.1.4 --- Effect of stirring rates --- p.86 / Chapter 5.2.1.5 --- Effect of initial cell concentrations --- p.87 / Chapter 5.2.2 --- Comparison of PCO inactivation efficiency between S. saprophyticus and E. cloacae --- p.88 / Chapter 5.2.3 --- PCO disinfection using different photocatalysts --- p.89 / Chapter 5.2.3.1 --- Ag/P25 --- p.89 / Chapter 5.2.3.2 --- SiO2-TiO2 and Cu2O/P25 --- p.90 / Chapter 5.3 --- PCO disinfection under visible light irradiation --- p.90 / Chapter 5.3.1 --- Effect of Cu20/P25 concentrations --- p.91 / Chapter 5.3.2 --- Effect of CU2O powder on the two bacterial species --- p.92 / Chapter 5.4 --- Feasibility use of fluorescent lamps for PCO disinfection --- p.93 / Chapter 5.5 --- Transmission electron microscopy (TEM) --- p.95 / Chapter 5.5.1 --- Morphological changes induced by PCO using P25 as a photocatalyst --- p.95 / Chapter 5.5.2 --- Morphological changes induced by PCO using CU2O/P25 as a photocatalyst --- p.96 / Chapter 5.6 --- Catalase (CAT) test --- p.98 / Chapter 5.7 --- Superoxide dismutase (SOD) activity assay --- p.99 / Chapter 6. --- Conclusion --- p.101 / Chapter 7. --- References --- p.106 / Chapter 8. --- Appendix --- p.121
70

Diversidade da comunidade bacteriana endofítica de sementes de soja e o seu potencial biotecnológico / Endophytic bacterial community diversity of soybean seeds and its biotechnological potential

Laura de Castro Assumpção 19 January 2009 (has links)
Tecidos vegetais, incluindo as sementes, são habitados por microrganismos denominados endofíticos, cuja interação com a planta pode conferir características vantajosas ao hospedeiro. Sabe-se que o crescimento de plantas é influenciado por fatores como a síntese de ácido-indolacético (AIA), solubilização de fosfato, fixação de nitrogênio e controle de fungos fitopatogênicos. Antes da comercialização, as condições de armazenamento de sementes de soja podem restringir o desenvolvimento de microrganismos devido à baixa temperatura e umidade. Esse fato leva ao interesse de exploração de microrganismos endofíticos resistentes a essas condições. O estudo e a caracterização dessas comunidades são de grande interesse agronômico e biotecnológico, sendo possível sua aplicação em sementes, introduzindo no campo plantas com superior potencial de produção. Com os objetivos de comparar a comunidade bacteriana endofítica de sementes de soja geneticamente modificadas e convencionais; e de isolar e caracterizar essas comunidades, sementes de 12 cultivares de soja foram amostradas, de onde 3504 isolados bacterianos foram obtidos. Os isolados foram agrupados morfologicamente de acordo com a coloração e taxa de crescimento das colônias, sendo representantes de cada grupo morfológico (no total 176 isolados) agrupados pela técnica de ARDRA (Análise de Restrição de DNA Ribossomal Amplificado). Um total de 12 ribotipos foi observado compondo a comunidade cultivada de bactérias endofíticas de sementes de soja. Representantes destes ribotipos tiveram seus genes 16S rDNA parcialmente sequenciados, identificando os integrantes desta comunidade como: Acinetobacter sp., Bacillus sp., Brevibacterium sp., Chryseobacterium sp., Citrobacter sp., Curtobacterium sp., Enterobacter sp., Methylobacterium sp., Microbacterium sp., Micromonospora sp., Pantoea sp., Paenibacillus sp., Pseudomonas sp., Ochrobactrum sp., Streptomyces sp. e Tsukamurella sp. A comunidade bacteriana endofítica de sementes de soja provenientes de plantas genticamente modificadas apresentou uma diversidade maior comparada à comunidade bacteriana de plantas convencionais. Em relação ao potencial biotecnológico desta comunidade, os resultados demonstraram que os isolados foram capazes de controlar o crescimento de fungos fitopatogênicos por antagonismo (18%), sintetizar AIA (100%), solubilizar fosfato (39%) e fixar nitrogênio (18%). Os isolados com os melhores resultados nas análises in vitro foram inoculados em sementes de soja e avaliados em casa de vegetação quanto à habilidade de promover o crescimento das plantas. As plantas apresentaram diferentes respostas à inoculação das bactérias. A maior parte dos tratamentos mostrou influência negativa das bactéria nas plantas, enquanto que um isolado de Enterobacter sp. aumentou a massa da matéria seca de raiz. Mesmo não diferindo estatisticamente, alguns isolados mostraram tendência de aumento e outros de diminuição de biomassa da planta. / Plant tissues, including seeds, are inhabited by microorganisms called endophytes, whose interaction with the plant can offer advantages to the host. It is known that plants growth promotion is induced by indole acetic acid (IAA) synthesis, phosphate solubilization and nitrogen fixation, among others. The control of phytopathogenic fungi is also related to a good plant development. Before commercialization, the seed storage conditions can restrict the development of microorganism, due to the low temperature and humidity. This fact leads to the interest of exploring resistant microorganisms to those conditions. The study and the characterization of these communities are of great agronomic and biotechnological interest, being possible its application onto seeds, introducing in the field plants with a greater production potential. In this context, the aim of this study was to isolate and identify the endophytic bacteria community in soybean seeds and study the capacity of these isolates to promote growth in the host plant, including: phosphate solubilization, nitrogen fixation, IAA synthesize and antagonism against phytopathogenic fungi. From seeds of 12 cultivars, 3504 bacteria were isolated. The isolates were morphologically grouped according to the coloration and growth rate of the colony. Representatives of each morph group, totalizing 176, were analyzed using the Amplified Ribosomal Restriction Analysis (ARDRA) technique. A total of 12 ARDRA ribotypes were observed in the cultivable endophytic community of soybean seeds. Representatives of each ribotype had their 16S rDNA gene partially sequenced, allowing to the identification of the members of this community as: Acinetobacter sp., Bacillus sp., Brevibacterium sp., Chryseobacterium sp., Citrobacter sp., Curtobacterium sp., Enterobacter sp., Methylobacterium sp., Microbacterium sp., Micromonospora sp., Pantoea sp., Paenibacillus sp., Pseudomonas sp., Ochrobactrum sp., Streptomyces sp. and Tsukamurella sp. The endophytic bacterial community of soybean seeds from genetically modified plants showed a greater diversity compared to the bacterial community of conventional seeds. In relation to the biotechnological potential of the community, the outcomes demonstrate that the isolates were able to antagonist phytopathogenic fungi (18%), synthesize IAA (100%), solubilize phosphate (39%) and fix nitrogen (18%). The isolates with best in vitro outcomes were inoculated onto seeds and tested in greenhouse for their ability to promote growth in soybean. The plants answered differently to the inoculation of each bacterial isolate. The major part of the treatments demonstrated a negative influence of bacteria onto plants, while one Enterobacter sp. isolate increased the dry mass weight of roots. Even not differing statistically, some isolates showed a tendency to increase, meanwhile others to decrease the biomass of the plant.

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