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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.
31

Estudo do comportamento térmico dos antibióticos aminoglicosí­deos estreptomicina e tobramicina / The study of the thermal behavior of the aminoglycoside antibiotics streptomycin and tobramycin

Caroline Bevilacqua Micalli 10 August 2018 (has links)
Este trabalho propõe estudos sobre a caracterização do comportamento térmico dos aminoglicosídeos estreptomicina e tobramicina, que são antibióticos bactericidas, utilizados no combate a microorganismos patogênicos, que agem interrompendo a síntese de proteínas. Após a caracterização espectroscópica dos analitos, foram realizadas medidas termogravimétricas, em atmosfera de ar e nitrogênio, que possibilitaram a determinação da estabilidade térmica do fármaco e o reconhecimento das etapas de decomposição. A calorimetria exploratória diferencial forneceu informações a respeito de processos físicos com variação de entalpia. Os gases envolvidos foram analisados usando termogravimetria acoplada à espectroscopia vibracional na região do infravermelho (TG-FTIR), possibilitando a proposta de um mecanismo para sua decomposição térmica. Intermediários de decomposição térmica foram caracterizados por CG-MS e o conjunto de todas essas informações forneceu um possível mecanismo para o comportamento térmico dessas drogas. Também foi sintetizado, caracterizado e analisado por TG, DSC e TG-FTIR, o complexo de tobramicina com o íon Cu+2. / A study regarding the thermal behavior characterization of the aminoglycosides streptomycin and tobramycin which are bactericidal antibiotics is presented. These antibiotics are widely against pathogenic microorganisms and act by interrupting the synthesis of proteins. Thermogravimetric measurements were performed under air and nitrogen conditions. To evaluate thermal stability of the drugs and their decomposition steps. A differential scanning calorimetry provided information on physical processes with enthalpy change. Evolved gas analysis was performed using thermogravimetry coupled to infrared spectroscopy (TG-FTIR), and was used to characterize the gases released during the thermal heating of the samples. Decomposition intermediates were characterized by CG-MS and the set of all these resultsallowed the proposition of a mechanism for the thermal behavior of drugs. The complex of tobramycin with the Cu+2 ion was also synthesized, characterized and analyzed by TG, DSC and TG-FTIR.
32

Desenvolvimento e validação de metodos analititicos para a deteminação de residuos de estreptomicina e diidroesteptominicina em leite bovino (ELISA, LC-APCI-MS/MS QToF) / Development and validation of analytical methos for the determination of streptomycin and ddihydrostreptomycin residues in milk (ELISA, LC-APCI-MS/MS QToF)

Oliveira, Renata Cabrera de, 1984- 13 August 2018 (has links)
Orientador: Felix Guillermo Reys Reys / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-13T21:39:01Z (GMT). No. of bitstreams: 1 Oliveira_RenataCabrerade_M.pdf: 696928 bytes, checksum: 7026171fdbd90be240a19f0afb58a12c (MD5) Previous issue date: 2009 / Resumo: A presença de resíduos de medicamentos veterinários em níveis acima dos limites máximos (LMR) estabelecidos apresentam riscos à saúde humana. O conhecimento da dimensão da exposição da população a esses compostos é necessário para garantir a proteção do consumidor. Para tanto, é imprescindível que métodos de análise validados estejam disponíveis, para assegurar a confiabilidade dos resultados. O objetivo deste trabalho foi desenvolver e validar métodos analíticos para a determinação de resíduos de estreptomicina e diidroestreptomicina em leite e empregá-los na análise de amostras comercializadas na região de Campinas, São Paulo. Os métodos analíticos desenvolvidos e validados incluem o ensaio imunoenzimático (ELISA) e a cromatografia líquida associada à espectrometria de massas em tandem (LCMS/MS QToF). A validação analítica foi realizada de acordo com as recomendações da Comunidade Européia e IUPAC. Os seguintes parâmetros foram avaliados: seletividade, curva analítica, linearidade, sensibilidade, precisão (repetibilidade intra e inter-dias), exatidão e limites de detecção e de quantificação. Os resultados do procedimento de validação dos métodos de ELISA e LC-MS/MS demonstraram que estes são adequados para a análise de triagem e confirmatória, respectivamente, de resíduos de estreptomicina e diidroestreptomicina em leite pasteurizado, em níveis de concentração inferiores ao LMR estabelecido para essas substâncias (200 µg kg-1). Nas amostras analisadas não foram encontrados resíduos de estreptomicina e diidroestreptomicina em níveis detectáveis / Abstract: Veterinary drugs pose a risk to human health when there residual levels in foods exceed the maximum residue limit (MRL). Knowledge of the extent of human exposure to these compounds is necessary to provide consumer protection. To achieve this, it is essential that validated analytical methods are available to ensure reliable results. The aim of the present work was to develop and validate analytical methods for the analysis of streptomycin and dihydrostreptomycin residues in milk, and to employ these methods for analysis of samples marketed in the region of Campinas, São Paulo. The developed and/or validated methods include enzyme immunoassay (ELISA) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS QToF). Method validation was performed according to the recommendations established by European Community and IUPAC. The following parameters were evaluated: analytical curve, linearity, sensitivity, precision (intra and inter-day repeatability), accuracy and the detection and quantification limits. The results demonstrated the effectiveness of ELISA and LCMS/MS methods for trial and confirmatory analyses, respectively, of streptomycin and dihydrostreptomycin in milk at concentrations below the established MRL (200µg kg-1). In the analyzed samples streptomycin and dihydrostreptomycin were not found at detectable levels / Mestrado / Mestre em Ciência de Alimentos
33

A ribosomal gene mutation in streptomycin resistant mycobacterium tuberculosis isolates

Douglass, John Wingfield 18 April 2017 (has links)
No description available.
34

Establishment and characterization of a mouse model of chronic Salmonella enterica infection as a proposed animal model for human inflammatory bowel disease

Seydel, Aleksandra 07 January 2020 (has links)
The aim of this study was to establish a bacteria-induced mouse model of human IBD applicable for investigation of the role of commensal versus pathogenic bacteria in the onset and development of chronic intestinal inflammation. The mouse model introduced in the present work focused on chronic inflammatory reaction triggered by S. enterica infection. Furthermore, differences between the acute and chronic phase of infection were analyzed. Additionally, it was investigated, whether antibiotic treatment prior to infection has a significant impact on the course of the systemic or local mucosal immune response against S. enterica. Due to the significant increase of the IL-22 level reported from IBD patients, and the assumed crucial role of this immunoregulatory cytokine for human IBD a special focus of this study was to analyze the role of IL-22 in the established mouse model of bacteria-induced chronic colitis.
35

[en] INTERACTION OF AMINOGLYCOSIDES WITH GOLD NANOPARTICLES AND THE SPECTROPHOTOMETRIC PROBE FOR THE DETERMINATION OF TOBRAMYCIN / [pt] INTERAÇÃO ENTRE AMINOGLICOSÍDEOS E NANOPARTÍCULAS DE OURO E O DESENVOLVIMENTO DE SONDA PARA A DETERMINAÇÃO ESPECTROFOTOMÉTRICA ULTRA TRAÇO DE TOBRAMICINA

HELLEN SILVA SANTOS 30 April 2019 (has links)
[pt] Os aminoglicosídeos (AMG) pertencem a uma classe de antibióticos eficazes no tratamento de infecções provocadas por micro-organismos Gram-negativos e Gram-positivos. Ototoxidade, nefrotoxidade e alterações musculares são efeitos colaterais provocados pelo uso dessas substâncias, implicando na importância do controle das medicações com uso de métodos analíticos práticos para a rotina, sensíveis e seletivos. As estruturas dos AMG não possuem grupos cromóforos que habilitem a medição de atividade óptica direta, dessa maneira, os métodos descritos na literatura para determinação dos mesmos, normalmente, fazem uso da derivatização química implicando em alta morosidade, elevados custos e toxicidade (dados os reagentes utilizados) em tais métodos. No presente trabalho, propõe-se a utilização de nanopartículas de ouro (AuNPs) como sondas analíticas para a determinação espectrofotométrica de AMG, tirando-se proveito do efeito de ressonância plasmônica na superfície de AuNPs. Investigou-se o potencial analítico do uso de dispersões aquosas de AuNPs como sondas para a determinação de tobramicina (TBR), neomina (NEO), gentamicina (GENTA), canamicina (CANA), estreptomicina (EST) e amicacina (AMIC), observando-se resultados promissores para todos os AMG citados, excerto para a EST. No caso da TBR, foi desenvolvido um método analítico para a sua determinação em soluções oftálmicas. As curvas analíticas foram construídas a partir do monitoramento da luz transmitida em 529 nm ou 681 nm. O monitoramento do sinal analítico em 529 nm apresentou uma faixa linear entre 6,5 x 10-9 mol L-1 a 1,6 x 10-7 mol L-1 com boa linearidade (R2=0,9943) e limite de detecção (LD) igual a 6,2 x 10-9 mol L-1. O monitoramento do sinal analítico em 681 nm apresentou uma faixa linear entre 4,4 x 10-9 mol L-1 a 1,6 x 10-7 mol L-1 com boa linearidade (R2=0,9949) e valor de LD igual a 3,8 x 10-9 mol L-1. O método mostrou-se robusto em uma faixa de pH entre 2,6 e 4,5, durante 120 min. O método apresentou precisão satisfatória e demonstrou seletividade com relação a outro AMG, STP, e com relação aos excipientes presentes nas amostras analisadas. Obtiveram-se percentuais de recuperação para as amostras (simuladas e reais de soluções oftálmicas) de 104,0 a 123,1 por cento e de 101,1 a 123,6 por cento, para o monitoramento do sinal analítico em 529 nm e 681 nm, respectivamente. Utilizando-se um método comparativo para validar esses resultados, verificou-se através do teste t-student que os percentuais de recuperação encontrados através das sondas de AuNPs e através do método comparativo foram estatisticamente iguais. Estudos com saliva de pacientes em tratamento com TBR indicam o potencial da sonda para a análise de fluidos biológicos. / [en] Aminoglycosides (AMG) belong to a class of antibiotics effective for the treatment of infections caused by Gram-negative and Gram-positive micro-organisms. Ototoxicity, nephrotoxicity and muscle disorders are side effects of using these substances, implying the importance of controlling the use of pharmaceutical formulations based on AMG with practical analytical methods for routine, sensitive and selective. The molecular structures of the AMG does not present any relevant chromophores groups that enable direct measurement of their optical activity, thus, the methods described in the literature for determining it normally to use of chemical derivatization implying high delays, high costs and toxicity (dice reagents used) in such methods. The studies present in this dissertation, it is proposed to use of gold nanoparticles (AuNPs) as analytical probes for spectrophotometric determination of AMG, by exploration of the resonance Plasmon effect on the surface of AuNPs. Was investigated the analytical potential of aqueous dispersions of AuNPs as probes for the determination of tobramycin (TBR) neomina (NEO), gentamicin (GENTA), kanamycin (CANA), streptomycin (EST) and amikacin (AMIC). Promising results were found for all AMG cited excerpt EST. In the case of TBR, an analytical method for its determination in ophthalmic solutions was proposed. The analytical curves were constructed by monitoring the transmitted light at 529 nm or 681 nm. The monitoring of the analytic signal in 529 nm yielding a linear range from 6.5 x 10-9 mol L-1 to 1.6 x 10-7 mol L-1 with good linearity (R2= 0.9943) and the limit of detection (LOD) equal to 6.2 x 10-9 mol L-1. The monitoring of the analytic signal in 681 nm yielding a linear range from 4.4 x 10-9 mol L-1 to 1.6 x 10-7 mol L-1 with good linearity (R2= 0.9949) and the LOD equal to 3.8 x 10-9 mol L-1. The method showed to be robust in a pH range between 2.6 and 4.5, for 120 min. The method showed satisfactory accuracy and demonstrated selectivity with respect to other AMG, EST, and with respect to excipients present in the samples analyzed. Yielded percentage recoveries for samples (simulated and real ophthalmic solutions) from 104.0 to 123.1 percent and from 101.1 to 123.6 percent, for the monitoring of the analytical signal at 529 nm and 681 nm, respectively. Using a comparative method to validate these results, it was found through the t-student test that the percentage recovery found through the AuNPs probes and the comparative method were statistically equal. Studies in saliva from patients under TBR treatment indicated the potential of the probe for the analysis of biological fluids.
36

Multiple Antibiotic Resistance Of Surface Mucus Dwelling Bacterial Populations In Freshwater Fish

Ozaktas, Tugba 01 December 2007 (has links) (PDF)
Surface mucus of a freshwater fish, Alburnus alburnus (bleak), caught from Lake Mogan, situated in south of Ankara, was collected in different seasons. The total cultivable bacteria were enumerated by spread plate method on nine different media. Bacteria were isolated based on colony morphologies and pigmentation. A total of sixty bacterial isolates obtained. The mucus-dwelling bacteria were first tested for resistance against ampicillin and kanamycin / then streptomycin and chloramphenicol were added to the experimental set up. The resistance levels of isolates were determined in terms of four antibiotics by tube dilution method. About 90% of the isolates were resistant to chloramphenicol, about 84% to kanamycin, about 88% to streptomycin and about 98% to ampicillin. These high levels of antibiotic resistance are rather interesting from a standpoint that the lake has no record of antibiotics exposure of any sort. The plasmid isolations were carried out to determine if the multiple antibiotic resistance could be attributed to plasmids for starting assumption. But we found no direct relationship between the presence of plasmids and multiple antibiotic resistance. Our study indicated that multiple antibiotic resistance at high levels is among the current phenotypes of the fish mucus-dwelling bacterial populations in Lake Mogan.
37

Mecanismos de proteção da distrofia muscular : estudo proteômico e terapia farmacológica / Protective mechanisms of muscular dystrophy : proteomic study and pharmacological therapy

Matsumura, Cintia Yuri, 1981- 21 August 2018 (has links)
Orientador: Maria Julia Marques / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-21T07:55:15Z (GMT). No. of bitstreams: 1 Matsumura_CintiaYuri_D.pdf: 2096053 bytes, checksum: 36802787c48fa671b02e82fdc5d9de40 (MD5) Previous issue date: 2012 / Resumo: Na Distrofia Muscular de Duchene (DMD) e em seu modelo experimental, camundongos mdx, a ausência ou disfunção da proteína distrofina leva a degeneração muscular. Acredita-se que a patogênese da DMD esteja relacionada à fragilidade do sarcolema, ao estresse mecânico e ao maior influxo de íons cálcio na fibra muscular resultante do funcionamento anormal de canais iônicos, como os canais de cálcio ativados por estiramento. O conhecimento das proteínas envolvidas na degeneração/regeneração muscular e na proteção a mionecrose da fibra muscular distrófica é essencial para a caracterização das distrofias musculares, bem como para o estabelecimento de métodos diagnósticos e de tratamentos preventivos ou terapêuticos. No presente trabalho estudamos os mecanismos de proteção a degeneração muscular, sendo dois os objetivos. No primeiro, identificamos proteínas envolvidas na proteção a mionecrose e nos processos de degeneração/regeneração muscular através do estudo proteômico dos músculos afetados ou não pela distrofia muscular em camundongos mdx e em animais controle. No segundo, verificamos a participação dos canais de cálcio ativados por estiramento na degeneração da fibra muscular através do seu bloqueio pela estreptomicina nos diferentes músculos distróficos de mdx. Adicionalmente, verificamos os potenciais efeitos secundários da estreptomicina na estabilidade do sarcolema e no tamponamento e sinalização de cálcio. Quanto ao estudo proteômico, nossos resultados sugerem que a diferença constitutiva dentre músculos afetados e não afetados pela degeneração são fundamentais para proteção a mionecrose, permitindo a manutenção da homeostase de cálcio e melhor resposta ao estresse mecânico e oxidativo. As proteínas galectina-1, anexina A1 e proteína 1 de interação com Reticulon-4 são possíveis biomarcadores para a distrofia muscular, uma vez que participam de diferentes processos celulares. Quanto a terapia farmacológica verificamos que os músculos distróficos mais afetados, como o diafragma, possuem maior quantidade de canais de cálcio ativados por estiramento e a estreptomicina atenuou a degeneração dos músculos distróficos. Diferente do efeito secundário de outros bloqueadores de canais de cálcio, a estreptomicina não alterou as proteínas do complexo distrofina-glicoproteína (beta-distroglicana e alfa-sintrofina), bem como as relacionadas ao cálcio (calsequestrina e calmodulina). Nossos resultados abrem novas perspectivas para o desenvolvimento de terapias farmacológicas relacionadas a proteínas envolvidas na degeneração muscular e na proteção a mionecrose, assim como para o desenvolvimento de métodos diagnóstico e de acompanhamento das distrofinopatias pelos marcadores moleculares / Abstract: In Duchenne Muscular Dystrophy (DMD) and in the mdx mice model of DMD, the lack of dystrophin leads to muscle degeneration. The pathogenesis of DMD is related to sarcolemmal fragility, mechanical stress and increased influx of calcium in muscle fibers, due to dysfunction of ion channels, such as the stretch-activated calcium channels. The knowledge of the proteins related to muscle degeneration/regeneration and to the protection against myonecrosis is essential to better characterize the muscular dystrophy and to establish new diagnostic tools, in addition to new preventive or therapeutic treatments. In the present study, we addressed new mechanisms of muscle protection by focusing on two main objectives. First, to identify proteins related to the protection agaisnt myonecrosis and to muscle degeneration/regeneration by performing a comparative proteomic study of spared and affected muscles of mdx and control mice. Second, to verify the involvement of stretch-activated calcium channels in dystrophic muscle degeneration by performing a drug therapy with a stretch-activated calcium channels blocker, streptomycin, in muscles that are differently affected by the lack of dystrophin, in the exercised-mdx mice. Furthermore, we were interested to see whether the stretch-activated calcium channels blocker would have additional effects on sarcolemal stability and on calcium buffering and signaling, as previously reported for other calcium channels blockers. The proteomic study suggests that constitutive differences among spared and affected dystrophic muscles are essential for muscle protection agaisnt myonecrosis, allowing a better calcium homeostasis and response to oxidative and mechanical stress. Galectin-1, annexin A1 and the protein interacting with Reticulon-4 are potencial biomarkers for muscular dystrophy, due to their involvement in different cellular processes. The drug therapy study shows that stretch-activated calcium channels participates in dystrophic muscle degeneration, showing higher levels in the mostly affected muscle, the diaphragm. Streptomycin protects the dystrophic muscles against myonecrosis, but has no further effects on other mechanisms of dystrophic muscle protection, i.e., did not improve the dystrophin-glycoprotein complex (assayed by beta-dystroglycan and alpha-syntrofin levels), nor calcium binding protein (assayed by calsequestrin and calmodulin levels). Overall, the present study opens new perspectives for the development of drug therapies to dystrophinopathies by suggesting potential new molecular markers of dystrophy (proteomic study) and by suggesting new mechanistic views to explain the differences in the response of dystrophic muscles to the lack of dystrophin (drug therapy) / Doutorado / Anatomia / Doutor em Biologia Celular e Estrutural
38

A description of the hearing profile in gold miners with tuberculosis

Brits, Janet 12 December 2011 (has links)
Two of the primary occupational health threats to employees in the mining industry are noise-induced hearing loss (NIHL) and occupational lung diseases (OLD) with Tuberculosis (TB) included in the latter. The objective of this study was to investigate the hearing profile of a group of gold miners with and without TB to determine the effect of TB and its associated risk profile on hearing. Workers in AngloGold Ashanti mine in South Africa were recruited due to the fact that they present with these two health threats namely NIHL and TB. The audiological and medical surveillance data of 2698 subjects (between the years 2001 and 2009) were used in analyses. Hearing thresholds for the air conduction frequencies (0.5, 1, 2, 3, 4, 6, 8 KHz) in both ears were analysed in conjunction with biographic and occupational data. Subjects were divided into three groups, two experimental groups (Single TB treatment, n= 911 and Multiple TB treatment, n= 376) and one control group (n= 1411). A highly significant difference (p<0.01) was noted between the control group and both TB treatment groups across most frequencies and hearing parameters analysed, although the higher frequencies were more affected. Pair wise comparisons revealed the largest differences in hearing thresholds throughout between the control group and the multiple TB treatment groups. The smallest differences in hearing thresholds were evident between the two TB groups with the multiple TB treatment group presenting with the poorest thresholds. TB and its related risk profile had a pronounced influence on the decline of hearing thresholds. Thresholds for the multiple TB treatment group indicated more deterioration than the hearing thresholds of the single TB treatment group. This may point to the possibility that the influence of repeated TB on the subjects’ hearing thresholds over time was more pronounced than a single incidence of TB. It is still necessary however to separate the effects of the disease from the effects of the treatment on hearing. / Dissertation (MCommunication Pathology)--University of Pretoria, 2012. / Speech-Language Pathology and Audiology / Unrestricted
39

THE EFFICACY OF STREPTOMYCIN VESTIBULAR NEURECTOMY TO ALLEVIATE VERTIGO AND FLUCTUANT HEARING LOSS ASSOCIATED WITH MÉNIÉRE'S DISEASE

GRACE, STEPHANIE LUBITZ 21 May 2002 (has links)
No description available.
40

Identificação de genes com expressão modulada por estreptomicina e de genes associados à virulência e patogenicidade em Xylella fastidiosa / Identification of genes modulated by streptomycin and of genes related to virulence and pathogenicity in Xylella fastidiosa

Silva, Patrícia Isabela Pessoa da 23 April 2010 (has links)
Em concentrações subletais, agentes antimicrobianos modulam a expressão gênica bacteriana, sendo que o conjunto de genes que é modulado depende tanto da cepa bacteriana, como da natureza do agente antimicrobiano. Neste trabalho, avaliamos o perfil de expressão gênica de Xylella fastidiosa cepa 9a5c em resposta ao tratamento por até 60 minutos com dose subletal do antibiótico estreptomicina. Esta é uma cepa virulenta, originalmente isolada de laranjeiras com sintomas de clorose variegada dos citros. A hibridização de microarranjos de DNA representando 2608 das 2848 sequências codificadoras (CDS) previamente anotadas no genoma desta cepa, revelou que 136 CDS apresentaram expressão gênica diferencial em resposta à exposição à estreptomicina, sendo que destas 109 foram negativamente moduladas e 27 positivamente moduladas. Realizamos, também, ensaios de PCR quantitativo precedido de transcrição reversa (RTqPCR) de 21 CDS para confirmar a modulação observada na análise global da expressão gênica. O perfil de expressão gênica de X. fastidiosa em resposta à estreptomicina foi analisado de forma integrada com outros perfis de expressão gênica desta bactéria. Entre as CDS positivamente moduladas, destacamos aquelas codificadoras das chaperoninas GroEL e GroES, que estão associadas a resposta de choque térmico, e CDS associadas à tradução, tais como proteínas ribossomais e fatores de tradução. Interessantemente, a exposição à estreptomicina induz a expressão da CDS que codifica poligalacturonase, que é um fator de virulência em algumas cepas de X. fastidiosa. Por outro lado, o tratamento com estreptomicina promoveu a modulação negativa de CDS relacionadas à formação e manutenção de biofilme ao contrário do observado quando estas bactérias foram submetidas ao tratamento com gomesina, um peptídeo antimicrobiano. O conjunto destas observações sugere que a exposição à dose subletal de estreptomicina possa promover um fenótipo de maior virulência, contrariamente ao efeito previamente observado com a gomesina. Neste trabalho, também descrevemos o pirosequenciamento do genoma da cepa J1a12 de Xylella fastidiosa, que exibe fenótipo menos virulento em citros e tabaco em relação à cepa 9a5c. A comparação da sequência genômica destas duas cepas confirma diferenças anteriormente observadas utilizando-se microarranjos de DNA e destaca genes potencialmente importantes para virulência de Xylella fastidiosa. / At sublethal concentrations, antimicrobials compounds modulate bacterial gene expression and the gene set that is modulated depends not only on the bacterial strain but also on the nature of antimicrobial agent. In this study, we evaluated changes in gene expression profile of Xylella fastidiosa strain 9a5c exposed up to 60 min to sublethal concentration of streptomycin. This a virulent strain originally isolated from orange trees with symptoms of citrus variegated chlorosis. Hybridization of DNA microarrays representing 2,608 out of 2848 coding sequences (CDS) previously annotated in strain 9a5c genome revealed 136 CDS differentially expressed upon streptomycin treatment. Of which 109 were down-regulated and 27 up-regulated. Differential expression for a subset of 21 CDS was further evaluated by reverse transcriptionquantitative PCR (RT-qPCR). In addition, we performed an integrated analysis of the gene expression profile of X. fastidiosa in response to streptomycin along with other gene expression profiles available for this bacterium. Among the up-regulated CDS, we highlight those encoding chaperonins GroEL and GroES, which are associated with heat shock response, and those CDS related to translation, such as ribosomal proteins and translation factors. Interestingly, exposure to streptomycin induces the expression of a CDS encoding polygalacturonase, which is a virulence factor for some X. fastidiosa strains. Furthermore, treatment with streptomycin down-regulates some CDS related to biofilm formation oppositely to treatment with gomesin, an antimicrobial peptide. Together, these observations suggest that exposure to sublethal dose of streptomycin might promote a higher virulent phenotype, in contrast to the effect previously observed with gomesin. In the present work, we also describe the pyrosequencing of J1a12 genome, a X. fastidiosa strain that exhibits a less virulent phenotype in citrus and tobacco if compared to strain 9a5c. A comparison of genome sequences of these two strains confirms differences previously observed using DNA microarrays and highlights important genes for virulence of X. fastidiosa.

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