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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.
91

Examination of Strain-Dependent Differences in S. sanguinis Virulence and Growth

Baker, Shannon 01 January 2019 (has links)
Streptococcus sanguinis, an abundant and benign inhabitant of the oral cavity, is an important etiologic agent of infective endocarditis, particularly in people with pre-disposing cardiac valvular damage. Although commonly isolated from patients with IE, little is known about the factors that make any particular S. sanguinis isolate more virulent than another or, indeed, whether significant differences in virulence exist among isolates. To investigate the virulence of multiple isolates, a variation of the Bar-seq (barcode sequencing) method was employed. A conserved chromosomal site was identified for subsequent insertion of a barcode identifier, unique for each strain. Barcode insertion did not affect growth in vitro or in a rabbit model of endocarditis. Pooling of these strains and inoculation into rabbits demonstrated that all strains were capable of causing disease; however, virulence varied widely among strains. Genomic comparisons of the more virulent strains versus less virulent strains failed to conclusively identify any single gene responsible for virulence. Given this result, we continued our examination of the manganese transport system SsaACB, which is present in every strain of S. sanguinis examined. Although its contribution to virulence has not been confirmed in any strain other than SK36, it has been shown to be required for virulence in multiple species of streptococci, making it a candidate for emerging targeted therapies. In S. sanguinis strain SK36, previous studies have confirmed that loss of the manganese transport protein SsaB is tantamount to loss of virulence. Moreover, ssaB-deficient mutants are deficient for serum growth—a phenotype we have previously found to be associated with virulence. Our in vitro studies of manganese transporter-deficient strain SK36 supported this, but also revealed the emergence of suppressor mutants. In each suppressor mutant that was isolated, mutations were identified that mapped to a common gene, SSA_0696. Deletion of SSA_0696 resulted in restored in vitro growth in the ssaACB-deficient background, unearthing a novel mechanism for bacterial growth under manganese limitation. Fortunately, the suppressor mutant phenotype was not maintained in vivo; however, the combined results of these experiments suggest the efficacy of future therapeutics may require consideration of virulence at the species level and the incorporation of multiple targets.
92

Prevalência das infecções cutâneas fúngicas em transplantados renais atendidos em hospital da Grande Vitória, ES

Ferreira, Priscila Ventorim Lisboa 14 August 2013 (has links)
Made available in DSpace on 2016-12-23T13:55:57Z (GMT). No. of bitstreams: 1 Priscila Ventorim Lisboa Ferreira.pdf: 1031724 bytes, checksum: c897be36746643eea3eee9da896e7d40 (MD5) Previous issue date: 2013-08-14 / Introdução: Diversas alterações cutâneas têm sido descritas nos pacientes transplantados renais, sendo a maior parte delas relativas aos efeitos imunossupressores diretos ou aos efeitos colaterais das drogas e podem ser agrupadas em infecções virais, bacterianas e fúngicas, lesões pré-neoplásicas e neoplásicas e iatrogênicas. Objetivos: 1- Determinar os agentes etiológicos e formas clínicas das micoses observadas nos pacientes transplantados renais estudados. 2- Correlacionar a ocorrência de micose com esquema imunossupressor. 3- Avaliar a prevalência de micoses em relação às dermatoses bacterianas e virais. Materiais e métodos: Estudo descritivo tipo corte transversal, com amostragem por conveniência, que avaliou 82 pacientes transplantados renais em regime de medicações imunossupressoras, atendidos em um hospital da Grande Vitória (ES), nos anos de 2011 e 2012. Após exame dermatológico foram realizados exames micológicos através de microscopia e cultura, quando necessários. Resultados: A casuística consistiu, na maioria, de pacientes do sexo masculino, pardos e com média de idade de 49,2 anos. O esquema imunossupressor mais frequente foi a combinação de Prednisona + Tacrolimus + Micofenolato sódico (46,3%) e foi o mais relacionado às dermatomicoses. O percentual de dermatomicoses foi de 28%, sendo 19,5% de onicomicoses, 6,1% de pitiríase versicolor e 2,4% de tineas. Com relação às dermatoses infecciosas, 7,3% apresentaram verrugas vulgares, 2,4% herpes simples e o mesmo percentual de 1,22% para molusco contagioso, erisipela e furunculose. O grupo de pacientes com transplante tardio (entre 3 e 5 anos) foi o que apresentou maior frequência de dermatomicoses. Conclusões: Os aspectos clínicos das dermatomicoses foram semelhantes, porém mais freqüentes que aqueles observados na população em geral. O percentual de dermatoses infecciosas foi similar ao da população imunocompetente / Introduction: Several cutaneous changes have been reported in renal transplant recipients, most of them due to immunosuppressive effects or side effects of the drugs and can be grouped into viral, bacterial and fungal infections, pre-neoplastic and neoplastic, and iatrogenic. Objectives: 1 - Determine the etiologic agents and clinical forms of mycoses observed in renal transplant recipients studied. 2 - Correlate the occurrence of fungal infection with immunosuppressive regimen and time of transplantation. 3 - Evaluate the frequency of bacterial and viral skin diseases. Materials and Methods: Descriptive cross-sectional study with convenience sampling, which evaluated 82 renal transplant recipients under immunosuppressive medications, treated at a hospital in Vitória (ES) in the years 2011 and 2012. After dermatological examination, skin scrapings were performed by light microscopy and mycological culture. Results: The sample consisted mostly of males and a mean age of 49.2 years. The most frequent regimen was the combination of Prednisone + Tacrolimus + Mycophenolate sodium (46.3%) and it was the most related to dermatomycoses. The frequency of dermatomycoses was 28%, with 19.5% of onychomycosis, 6.1% of pitiryasis versicolor and 2.4% of Tineas. We also found 7.3% of common warts, 2.4% of herpes simplex and the same percentage of 1.22% for molluscum contagiosum, erysipelas and furunculosis. The group of patients with late transplant (between 3 and 5 years) showed the highest frequency of dermatomycoses. Conclusions: The clinical aspects of dermatomycoses was similar but it was more frequent than that observed in the general population. The percentage of cutaneous infections was similar to that of immunocompetent population
93

Diagnóstico histopatológico e imuno-histoquímico de micoses e oomicoses em animais domésticos / Histopathological and immunohistochemical diagnosis of mycoses and oomycoses in domestic animals

Galiza, Glauco José Nogueira de 31 March 2014 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This thesis was composed of three scientific papers. The first paper was the more comprehensive one. All necropsy and biopsy cases of mycoses and oomycosis diagnosed in domestic animals between 1990 and 2012 were analyzed. In the studied period, 29,686 exams (9,487 necropsy reports and 20,199 biopsy reports) performed at the Laboratório de Patologia Veterinária (LPV) of the Universidade Federal de Santa Maria (UFSM) were studied. Two hundred and thirty cases of mycosis or pythiosis (oomycosis) were found, being 179 cases (78%) of mycoses and 51 cases (22%) of pythiosis. The main diseases observed, in descending order of prevalence, were: pythiosis, candidiasis, aspergillosis, zygomycosis, dermatophytosis, mallasseziosis, cryptococcosis, megabacteriosis, and sporothrichosis. Pythiosis affected mainly horses and the mycosis affected mainly dogs and cats. The second article focused on the histomorphological and histochemical characteristics determinant for the histopathological diagnosis of this condition in dogs and cats. By the hematoxylin-eosin (HE) stain, the yeasts were round, with a central cell containing a nucleus, surrounded by a clear halo (usually non-stained capsule). The techniques of periodic Schiff acid (PAS), Grocott, and Fontana-Masson (FM) were utilized and demonstrated the wall of the yeast cells. The FM stain showed the melanin present in these cells. The Alcian blue and Mayer s mucicarmin stains showed mainly the yeast polysaccharide capsule. The diameter of the cells ranged from 1.67 to 10.00μm and the full diameter of the encapsulated yeasts varied between 4.17 e 34.16μm. Yeast buddings were better observed through the PAS stain and were narrow based, simple or multiple, mainly in the opposite poles of the cells, or forming chains. The third article emphasized an immunohistochemical (IHC) study of cases of aspergillosis and zygomycosis aiming to optimize the use of the IHC technique in the detection of Aspergillus spp. and zygomycetes in animal tissues. Two fungal-specific monoclonal antibodies were utilized in tissue fragments (formalin-fixed paraffin-embedded) previously diagnosed as aspergillosis or zygomycosis. Tissues were submitted to three different detection systems (two biotinilated and one nonbiotinilated). Both antibodies showed high specificity and sensitivity in the examined tissues. No cross-reactions were observed between the antibodies utilized and the agents evaluated (including cases of aspergillosis, zygomycosis, candidiasis, and pythiosis). However, nonspecific reactions were observed in hyphae of some cases, but were eliminated by mean of one of the detection systems used. The IHC technique showed to be a useful tool detecting and confirming aspergillosis and zygomycosis in this retrospective study. / Esta tese foi constituída de três partes que resultaram em três artigos científicos. O primeiro artigo foi o mais abrangente, onde todos os casos de micoses e pitiose diagnosticados em animais domésticos, provenientes de necropsias e biópsias entre 1990 e 2012, foram analisados. No período estudado foram revisados 9.487 protocolos de necropsias e 20.199 exames histopatológicos, totalizando 29.686 casos examinados no Laboratório de Patologia Veterinária da Universidade Federal de Santa Maria (LPV-UFSM). Do total de protocolos analisados, em 230 foram diagnosticadas micoses ou pitiose (oomicose), sendo 179 casos (78%) de micoses e 51 casos (22%) de pitiose. As principais doenças diagnosticadas, em ordem decrescente de prevalência, foram: pitiose, candidíase, aspergilose, zigomicose, dermatofitose, malasseziose, criptococose, megabacteriose e esporotricose. Os equinos foram os mais acometidos pela pitiose e os animais de companhia (cães e gatos) foram os mais acometidos pelas micoses. O segundo artigo enfocou as características histomorfológicas e histoquímicas determinantes no diagnóstico histopatológico da criptococose em cães e gatos. Pela técnica de hematoxilina-eosina (HE) as leveduras eram arredondadas, com célula central contendo um núcleo, circundada por um halo claro (cápsula geralmente não corada). As técnicas histoquímicas do ácido periódico de Schiff (PAS), Grocott e Fontana-Masson (FM) foram utilizadas e evidenciaram a parede das células das leveduras. Pelo FM observou-se a melanina presente nessas células. As técnicas do azul Alciano e da mucicarmina de Mayer evidenciaram principalmente a cápsula polissacarídica das leveduras. O diâmetro das células das leveduras variou de 1,67 a 10,00 μm e o diâmetro total das leveduras encapsuladas variou entre 4,17 e 34,16 μm. Os brotamentos foram melhor visualizados através do PAS e ocorreram em base estreita, de forma única ou múltipla, principalmente em polos opostos das células das leveduras ou formando uma cadeia. O terceiro artigo enfocou um estudo imuno-histoquímico (IHQ) em casos de aspergilose e zigomicose, visando a otimização do uso da técnica de IHQ na detecção de Aspergillus spp. e zigomicetos em tecidos de animais. Utilizaram-se dois anticorpos monoclonais fungo-específicos em fragmentos de tecidos (fixados em formol e embebidos em parafina) com diagnóstico histomorfológico prévio de aspergilose e zigomicose, os quais foram submetidos a três sistemas de detecção diferentes (dois biotinilados e um não biotinilado). Os dois anticorpos apresentaram alta especificidade e sensibilidade nos tecidos examinados. Não ocorreram reações cruzadas entre os anticorpos utilizados e os agentes etiológicos avaliados (incluindo casos de aspergilose, zigomicose, candidíase e pitiose). No entanto, reações inespecíficas foram observadas nas hifas em alguns casos, porém foram eliminadas através de um dos sistemas de detecção utilizados. A técnica de IHQ mostrou-se uma ferramenta muito útil na detecção e confirmação dos casos de aspergilose e zigomicose neste estudo retrospectivo.
94

Fungos anemófilos na cidade de Botucatu e sua correlação com sensibilização em portadores de doenças alérgicas respiratórias / Airborne fungi and their correlation with sensitization in patients with respiratory allergic diseases from the town of Botucatu

Elaine Gagete Miranda da Silva 05 May 2005 (has links)
Introdução: Fungos são alérgenos cuja importância nas doenças alérgicas respiratórias é subestimada por falta de extratos alergênicos adequados para diagnóstico, quer através de testes cutâneos, quer através de dosagem de IgE específica. Botucatu possui características próprias por se localizar numa \"cuesta\" e possuir vegetação variada que cobre grande parte da cidade. A partir das plantas os fungos ganham o ar através da esporulação podendo ser inalados e sensibilizar pacientes com alergias respiratórias. Este trabalho se propõe a estudar quais os fungos mais prevalentes em Botucatu e a taxa de sensibilização dos principais gêneros entre os portadores de asma e rinite procedentes dessa região. Casuística e Métodos: Foi desenvolvido um aparelho caça esporos para a captura dos mesmos em quatro pontos da cidade. Foram feitas cinco coletas/ponto/semana durante um ano para contagem e identificação das UFC (unidades formadoras de colônias). Foram selecionados pacientes de Botucatu e região com asma e rinite, nos quais se aplicou testes de puntura para os principais alérgenos, incluindo onze diferentes fungos. Foram também realizados testes intradérmicos com extratos de fungos nos pacientes cujo teste de puntura ao fungo em questão tenha sido negativo. Resultados: Foram identificados 67 gêneros sendo os mais prevalentes: Cladosporium, Epicoccum, Levedura, Aspergillus, Helminthosporium, Nigrospora, Monilia, Fusarium, Hyalodendrum, Penicillium, Curvularia, Humicola, Alternaria, Trichoderma e Sphaerosporium. Foram selecionados 207 pacientes dos quais 118 (57%) apresentaram pelo menos um teste positivo a fungo. O teste intradérmico foi responsável por 88% do diagnóstico de sensibilização A dosagem de IgE específica mostrou baixa sensibilidade (4%). Os fungos mais sensibilizantes foram: Aspergillus, Neurospora, Candida, Penicillium e Cladosporium. Observou-se maior positividade a fungos no grupo de asma grave, sendo que Aspergillus, Neurospora e Candida foram mais prevalentes nesse grupo. Encontrou-se associação positiva entre pacientes com asma atendidos em Pronto-Socorros durante o ano estudado e o total de UFC nesse período. Conclusões: Os fungos mais prevalentes no planeta são também encontrados em Botucatu, embora haja fungos característicos dessa região; a sensibilização a fungos é expressiva na população estudada e guarda relação com maior gravidade da asma; o teste intradérmico foi o melhor meio diagnóstico para sensibilização a fungos / Purpose: Fungi are allergens whose importance has been underestimated due to the absence of reliable extracts for the diagnosis of sensitization in vivo or in vitro. Botucatu has unique characteristics because of its location on a \"cuesta\" and its varied vegetation which cover a large area of the city. The fungi reach the air from the plants through sporulation and they can be inhaled and sensitize patients with allergic diseases. Here we studied the most prevalent fungi in the air of Botucatu and the rate of sensitization to the main fungi genus among patients with asthma and rhinitis. Methods: We developed a spore trap to catch the spores from the air in four points in the city. Five collections were taken weekly during a whole year. Colony forming units (CFU) were counted and the fungi on Petri dishes were classified. Patients with asthma and rhinitis have been selected and submitted to prick tests with the main allergens including eleven different types of fungi. Intradermal tests with fungi extract were also performed in the patients whose prick test to these fungi had been negative. Results: Sixty-seven genus of fungi have been identified and the more prevalent were: Cladosporium, Epicoccum, yeast, Aspergillus, Helminthosporium, Nigrospora, Monilia, Fusarium, Hyalodendrum, Penicillium, Curvularia, Humicola, Alternaria, Trichoderma and Sphaerosporium. Two hundred and seven patients have been selected and 118 (57%) have been at least one positive test to fungus. Intradermal test made the diagnosis in 88% of all diagnostics of sensitization, whereas \"in vitro\" specific IgE had low sensibility (4%). The more sensitizer fungi were: Aspergillus, Neurospora, Candida, Penicillium and Cladosporium. There was a significant correlation between severe asthma and fungi sensitization and the fungi more prevalent in that group of patient were: Aspergillus, Neurospora and Candida. Moreover, there was a positive correlation between the number of asthmatic patients attended in Emergencies and the total of CFU in the study period. Conclusion: We recognize in the air fungi specific to Botucatu although the most prevalent fungi are the same found in other places in the world; the fungi sensitization among patients with allergic respiratory diseases is meaningful and correlated with asthma severity; the intradermal test was the best mean to diagnose fungi sensitization
95

Piedra preta: características in vitro, aspectos ultraestruturais e identificação de novos agentes etiológicos

ROCHA, Ana Paula Santiago 20 February 2015 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-04-15T12:57:52Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Mestrado, Rocha,APS.pdf: 1946617 bytes, checksum: b6dc0fb29dac8660c791c1a05c3de947 (MD5) / Made available in DSpace on 2016-04-15T12:57:52Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Mestrado, Rocha,APS.pdf: 1946617 bytes, checksum: b6dc0fb29dac8660c791c1a05c3de947 (MD5) Previous issue date: 2015-02-20 / CAPEs / Piedra preta é uma micose superficial assintomática, caracterizada pela formação de nódulos rígidos e enegrecidos localizados ao longo do fio capilar. É uma micose considerada rara, inócua, podendo acometer tanto o gênero feminino quanto o masculino em qualquer faixa etária. Piedraia hortae, agente etiológico desta micose, é um fungo filamentoso, demáceo que produz o pigmento melanina, caracterizando uma coloração enegrecida na parede celular e nas estruturas fúngicas. Este pigmento, por sua vez, é caracterizado como um potente fator de virulência, favorecendo, desse modo, seu potencial em causar parasitismo no cabelo. Na literatura, não há referências citando que outros fungos demáceos, que formam ascostroma, ascos e ascosporos, semelhantes ao P. hortae, possam ser agente etiológico dessa feohifomicose. Assim, o objetivo desse trabalho foi avaliar a capacidade de fungos demáceos de formarem nódulos na porção extrafolicular de fios de cabelo humano, semelhantes aos da piedra preta. Foram obtidos onze isolados de fungos demáceos, sendo dez da Coleção de Cultura Micoteca URM, UFPE, os quais estavam preservados sob óleo mineral e posteriormente semeados em meio Àgar Batata Dextrose para estimulação do crescimento; e um isolado proveniente do Laboratório de Micologia Médica. Foram preparadas suspensões dos isolados dos fungos demáceos em 2,0 ml de água destilada esterilizada, ajustada para concentração final de 106 células/mL. Em seguida, vertidos separadamente 0,5 mL de cada suspensão sobre os fios de cabelo contidos nas placas de Petri previamente esterilizada e mantidas a temperatura de 28°C e 37°C. O experimento foi conduzido através de observações macroscópicas e microscópicas dos cabelos durante 40 dias e acompanhado em intervalo de 5 dias. Dois isolados (970 e 3334) mostraram um elevado potencial capaz de causar infecção no fio capilar. Entretanto, oito isolados apresentaram apenas uma colonização. Exophiala dermatitidis e Cladosporium tenuissimo foram capazes de formar nódulos semelhantes ao da piedra preta, porém estruturas de reprodução como ascostroma, ascos e ascosporos, não foram vizualizadas.Todavia, podemos inferir que esses fungos apresentam um potencial capaz de parasitar os fios de cabelo, degradando e destruindo a queratina e os componentes cutiulares, sendo o potente agente de tricomicose. / Black piedra is a superficial mycosis asymptomatic, characterized by the formation of hard lumps and blackened located along the capillary yarn. It is a mycosis considered rare, innocuous and can affect both the female and the male at any age. Piedraia hortae, the etiologic agent of this mycosis, is a filamentous fungus, dematiaceous that making the pigment melanin, featuring a blackish color in the cell wall and the fungal structures. This pigment, in turn, is characterized as a potent virulence factor, facilitating there by the potential to cause parasitic hair. In the literature, there are no references citing that other demáceos fungi that form ascostroma, asci and ascospores, similar to P. hortae, may be etiologic agent of this phaeohyphomycosis. The objective of this paper is to demáceos fungal ability to form nodules in extrafollicular portion of human hair, similar to those of black piedra. Eleven isolates of fungi demáceos, obtained of the Culture Collection URM, UFPE, which were preserved under mineral oil and then plated on potato dextrose agar medium for growth promotion; and one isolated from the Medical Mycology Laboratory. Fungal isolates demáceos suspensions were prepared in 2.0 ml of sterile distilled water, adjusted to a final concentration of 106cells / ml. Then separately poured into 0.5 mL of each suspension over the strands of hair contained in the previously sterile Petri dishes and kept at 28 °C and 37 °C. The experiment was conducted by macroscopic and microscopic observations of the hair for 40 days and monitoring in the range of 5 days. Two isolates (970 and 3334) showed a high potential capable of causing infection in the capillary. However, eight isolates showed only colonization. Exophiala dermatitidis and Cladosporium tenuissimo was capable of forming nodules were similar to those of black piedra; however ascostroma structures such as playback, asci and ascosporos were not displayed. However, we can infer that these fungi have the potential able to parasitize the hairs, degrading and destroying the keratin and cuticulares components, the powerful Trichomycosis agent.
96

Beyond Toll-Like Receptor 9: Interactions Between Plasmacytoid Dendritic Cells and Aspergillus Fumigatus: A Dissertation

Ramirez-Ortiz, Zaida G. 26 October 2010 (has links)
The opportunistic fungus, Aspergillus fumigatus, is a leading cause of morbidity and mortality among the immunocompromised population. Experimental and clinical findings have established that phagocytic defenses are critical in the recognition and clearance of A. fumigatus. Previous studies found that Toll-like receptors (TLRs), specifically TLR2 and TLR4, were essential in the detection of the mold. Furthermore, one study found that mice deficient in TLR9 lived longer than their wild-type counterparts following challenge with A. fumigatus. We sought to determine the role of TLR9 during A. fumigatus infection. Our results show that A. fumigatus contains unmethylated CpG DNA, the natural ligand of TLR9. Furthermore, A. fumigatus DNA stimulates a potent pro-inflammatory response in mouse bone marrow derived dendritic cells (BMDCs) and human plasmacytoid dendritic cells (pDCs). A genome wide analysis showed that A. fumigatus DNA contains 87 human and 23 mouse putative immunostimulatory motifs. The response to A. fumigatus DNA is TLR9-dependent, as BMDCs from TLR9-/- mice were unresponsive to the fungal DNA. In addition, HEK293 cells cotransfected with human TLR9 and NFκB driven Luciferase conferred responsiveness to A. fumigatus CpG-rich sequences found in the fungal DNA. Our results show that TLR9 detects A. fumigatus DNA, resulting in the secretion of proinflammatory cytokines. While pDCs secrete IFNα in response to A. fumigatus DNA, these cells have been mainly described to play critical roles in the antiviral responses. The role of pDCs during fungal infections remains to be elucidated. Our data show that CD304+ peripheral blood pDCs challenged with A. fumigatus hyphae secrete large concentrations of IFNα and TNFα in response to infection. Furthermore, the response appears to be TLR9- independent. However, pDCs spread over the hyphae and inhibit fungal growth. Furthermore, pDCs undergo cell lysis upon incubation with A. fumigatus. The antifungal activity of the pDCs was retained in the cell lysates, suggesting that this response was mediated by an intracellular factor. Addition of exogenous Zn2+, but not Fe3+, partially restores hyphal growth. In addition, western blot of pDC lysates show that these cells have the Zn2+-binding protein calprotectin. Over 60% cell death is observed in the pDC population following a 2 hour incubation with A. fumigatus. The observed pDC cell death can be partially attributed to gliotoxin, as pDCs challenged with A. fumigatus stains deficient in production of the mycotoxin result in decreased pDC cytotoxicity. Furthermore, pDC cell death occurs independent of contact with the mold, confirming that pDC cell death is mediated by a secreted fungal factor. In addition, our results show that pDCs are required for the host response against A. fumigatus. Mice depleted of their pDCs are more susceptible to A. fumigatus infection than the control counterparts, suggesting that pDCs play a role in the antifungal response. Also, we observe a 5-fold increase in the pDC population in the lungs of infected mice. Therefore, the possibility of these cells playing a role in recruiting and communicating with other immune cells cannot be eliminated. Upon maturation, pDCs acquire characteristics of conventional DCs (cDCs) such as upregulation of major histocompatability complex (MHC) and becoming more phagocytic. Whether mature pDCs are involved in the detection of and responses against fungal pathogens remains to be determined. Here we show that mature pDC secrete IFNα and TNFα in response to A. fumigatus conidia as early as 6 hours post-challenge. While cytokine secretion of mature pDCs against A. fumigatus does not require opsonization, it requires for A. fumigatus being alive and growing. Furthermore, supernatants from conidial growth induced cytokine secretion by the mature pDCs. The work presented in this thesis establishes that the nucleic acids in A. fumigatus serve as a pathogen associated molecular pattern (PAMP) that can induce a TLR9- dependent response. Furthermore, I show that pDCs secrete cytokines and induce an antifungal response against A. fumigatus conidia and hyphae. While the pDC population in the blood appears to be small, our work shows that these cells could be intimately involved in the antifungal responses against A. fumigatus.
97

Bioprospecção de produtos naturais em terapia fotodinâmica contra micro-organismos de interesse médico-odontológico /

de Oliveira, Analú Barros. January 2020 (has links)
Orientador: Fernanda Lourenção Brighenti / Resumo: Este trabalho está dividido em 2 publicações cujos objetivos foram: a) realizar uma revisão sistemática da literatura, seguida de uma metanálise sobre a eficácia da terapia fotodinâmica (TFD) nos micro-organismos responsáveis pela cárie dentária (Publicação 1); b) avaliar o potencial in vitro dos óleos essenciais de Coffea arabica, Matricaria recutita e Eugenia uniflora e dos extratos vegetais de Senna splendida, Senna reticulata e Senna Macranthera para serem utilizados como monoterapia na terapia fotodinâmica sobre suspensões de micro-organismos de interesse médico-odontológico. Publicação 1: A questão de pesquisa e as palavras-chave foram construídas de acordo com a estratégia do PICO. A pesquisa do artigo foi realizada nas bases de dados Embase, Lilacs, Scielo, Medline, Scopus, Cochrane Library, Web of Science, Science Direct e Pubmed. Ensaios clínicos randomizados e estudos in vitro foram selecionados na revisão. O estudo foi conduzido de acordo com as diretrizes do PRISMA para revisão sistemática. Publicação 2: Foram utilizadas as seguintes cepas de referência em suspensão: Cutibacterium acnes ATCC 6919, Streptococcus mutans ATCC 35688, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 e Candida albicans ATCC 90028. Os materiais vegetais foram testados nas concentrações de 50 μg/mL (extratos) ou 2% (óleos essenciais). Foram estudados cinco grupos: controle negativo, material vegetal sem exposição a luz (FS-luz), material vegetal com exposição a luz (FS+luz),... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
98

Taxonomie, diverzita a klinický význam rodu Aspergillus / Taxonomy, diversity and clinical relevance of the genus Aspergillus

Hubka, Vít January 2017 (has links)
Aspergillus is a speciose genus encompassing nearly 400 species that has significant economic impacts on human health, the food industry, biotechnology and pharmacology. The research included in this thesis focuses on current issues related to the generic concept, subgeneric classification and species delimitation in Aspergillus. It addresses the need for revisions of several sections or species complexes. It provides novel information regarding etiology of aspergillosis as well as the antifungal susceptibilities of several less common opportunistic pathogens. The taxonomic section of the thesis contributes to the taxonomic stability and the new concept of the genus Aspergillus, which changed in response to the discontinuation of dual nomenclature in fungi. Sufficient arguments were collected (e.g., verification of monophyly, unifying phenotypic characters) for maintaining a broad concept of the genus and avoiding splitting it into several genera. All genera typified by sexual morphs and having Aspergillus asexual states were synonymized with Aspergillus and the appropriate names adopted; new combinations were made for teleomorphic species that lacked Aspergillus names. This thesis also contributed to infrageneric taxonomy of the genus via the proposal of four new sections in the subg. Circumdati,...
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Activation and Inhibition of Multiple Inflammasome Pathways by the Yersinia Pestis Type Three Secretion System: A Dissertation

Ratner, Dmitry 11 May 2016 (has links)
Host survival during plague, caused by the Gram-negative bacterium Yersinia pestis, is favored by a robust early innate immune response initiated by IL-1β and IL-18. Precursors of these cytokines are expressed downstream of TLR signaling and are then enzymatically processed into mature bioactive forms, typically by caspase-1 which is activated through a process dependent on multi-molecular structures called inflammasomes. Y. pestis evades immune detection in part by using a Type three secretion system (T3SS) to inject effector proteins (Yops) into host cells and suppress IL-1β and IL-18 production. We investigated the cooperation between two effectors, YopM and YopJ, in regulating inflammasome activation, and found that Y. pestis lacking both YopM and YopJ triggers robust caspase-1 activation and IL-1Β/IL-18 production in vitro. Furthermore, this strain is attenuated in a manner dependent upon caspase-1, IL-1β and IL-18 in vivo, yet neither effector appears essential for full virulence. We then demonstrate that YopM fails to inhibit NLRP3/NLRC4 mediated caspase-1 activation and is not a general caspase-1 inhibitor. Instead, YopM specifically prevents the activation of a Pyrin-dependent inflammasome by the Rho-GTPase inhibiting effector YopE. Mutations rendering Pyrin hyperactive are implicated in the autoinflammatory disease Familial Mediterranean Fever (FMF) in humans, and we discuss the potential significance of this disease in relation to plague. Altogether, the Y. pestis T3SS activates and inhibits several inflammasome pathways, and the fact that so many T3SS components are involved in manipulating IL-1β/IL-18 underscores the importance of these mechanisms in plague.
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Host Cell Attachment by Lyme Disease and Relapsing Fever Spirochetes: A Dissertation

Benoit, Vivian M. 16 December 2010 (has links)
Host cell attachment by pathogenic bacteria can play very different roles in the course of infection. The pathogenic spirochetes Borrelia hermsii and Borrelia burgdorferi sensu lato which cause relapsing fever and Lyme disease, respectively, are transmitted by the bite of infected ticks. After transmission, these spirochetes can cause systemic infection. Relapsing fever spirochetes remain largely in the bloodstream causing febrile episodes, while Lyme disease will often colonize a variety of tissues, such as the heart, joint and nervous system, resulting in a chronic multisystemic disorder. Borrelia species have the ability to bind to various cell types, a process which plays a crucial role in pathogenesis and may influence spirochetal clearance from the bloodstream. Colonization of multiple tissues and cell types is likely promoted by the ability to bind to components found in target tissues, and many B. burgdorferi adhesins have been shown to promote attachment to a wide variety of cells and extracellular matrix components. Different Lyme disease strains have been shown to preferentially colonize certain tissues, although the basis of this tissue tropism is not well understood. In this study we found that among different Lyme disease strains, allelic variation of the adhesin DbpA contributes to variation in its in vitro binding activities raising the possibility that this variation contributes to tissue tropism in vivo. In studying B. hermsii infection, we found evidence by both histological and fluorescence in situ hybridization (FISH) analysis of tissues that indicated that red blood cells were removed by tissue resident macrophages in infected mice. Spirochetes in the spleen and liver were often visualized associated with RBCs, lending support to the hypothesis that direct interaction of B. hermsii spirochetes with RBCs leads to clearance of bacteria from the bloodstream. Our findings indicate that host cell attachment play a key role in the establishment of Lyme disease infection, and in contrast contributes to the clearance of relapsing fever infection.

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