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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

Detecção de Chlamydia trachomatis em amostras de urina masculina por reação em cadeia da polimerase

Aquino, Alzira Resende do Carmo January 2005 (has links)
Infecções por Chlamydia trachomatis estão entre as mais freqüentes doenças sexualmente transmissíveis (DST) em todo o mundo, apresentando grande importância epidemiológica. A identificação deste patógeno pode ser difícil e um método de detecção baseado na amplificação de ácidos nucleicos é altamente desejável, por sua acurácia e rapidez. O presente estudo avaliou a acurácia, sensibilidade e especificidade de uma reação em cadeia da polimerase (PCR) in “house” em amostras de urina de homens com e sem sintomas de DST comparados a um teste comercial, o COBAS Amplicor CT/NG (Roche, Suiça). Foram utilizados primers específicos para amplificar um segmento do plasmídio críptico de C. trachomatis gerando um fragmento de 201 pb, cuja seqüência foi confirmada por clivagem enzimática e seqüenciamento automático. A especificidade analítica dos primers foi confirmada frente ao DNA de diferentes microrganismos patogênicos e não patogênicos da microbiota urogenital masculina. A detecção limite do DNA clamidial pela PCR in house após hibridização (Southern blot), foi de 1 pg. O COBAS Amplicor CT/NG foi considerado o teste de referência por ser automatizado e conter um programa de controle interno da reação para identificar inibição da DNA polimerase. Entre as 37 amostras testadas positivas para C. trachomatis pelo COBAS Amplicor, 33 foram confirmadas positivas pela PCR in house. Foram detectados inibidores da reação nas 4 amostras que apresentaram resultados falso-negativos, utilizando-se a técnica de contaminação da reação com o DNA clamidial (spiked) e um controle interno da reação com primers que amplificam a β-globina do DNA humano. Após congelamento e descongelamento para eliminar prováveis substâncias inibidoras lábeis, as 4 amostras foram re-testadas, resultando na positividade de mais 2 amostras, completando 35 amostras positivas pela PCR in house. Entre as 74 amostras testadas negativas para C. trachomatis pelo COBAS Amplicor, 72 foram confirmadas negativas pela PCR in house. Das 2 amostras prováveis falso-positivas, apenas 1 permaneceu positiva, após re-teste. Dos 111 pacientes analisados, 108 apresentaram resultados idênticos nos dois testes, o equivalente a uma acurácia = 97,3%, sensibilidade = 94,6% e especificidade = 98,6%. A alta sensibilidade e especificidade apresentada pela PCR in house, demonstra a possibilidade de triar e diagnosticar C. trachomatis em urina de homens, importante reservatório da infecção clamidial para as mulheres. / Chlamydia trachomatis infections are among the most commum sexually transmitted diseases and of great epidemiological importance world-wide. Identification of this pathogen can be difficult, and it is highly desirable to have a rapid and accurate nucleic acid amplification based detection method. The present study was designe to evaluate the accuracy, sensitivity and specificity of a in house plasmid-based polymerase chain reaction (PCR) and hybridization on first void urine specimens from symptomatic and asymptomatic men, compared with a commercial test the PCR COBAS Amplicor CT/NG (Roche, Switzerland), for detection of C. trachomatis (CT). Specific primers for the cryptic plasmid of C. trachomatis were designed to amplify a 201 bp fragment confirmed by enzymatic cleavage and automatic sequencing. The analytic specificity was determined by submitting to the intended protocol, the DNA of normal and pathogenic urogenital microbiota, the specific primers anneling was confirmed. The detection limit of the PCR and the Southern blot hibridization, was mesured in 1 pg of chlamydial DNA. The COBAS Amplicor CT/NG was considered the reference test, it contains a internal control (IC) programme to identify DNA polymerase inhibition. Among 37 positive specimens tested by COBAS Amplicor, 33 were confirmed positive by in house PCR and inhibitors of PCR were demonstrated in the 4 possibly false-negative samples performing DNA chlamydial spiking experiments and using a positive internal control of human β-globin DNA. The specimens were freezedthowed and re-tested to remove labile inhibitors, but 2 samples remained negative. Among 74 negative specimens by COBAS Amplicor, 72 were confirmed negative by in house PCR. The 2 problaby false-positive samples were re-tested and just one remained positive. The final results of the two tests were identical for 108 of the 111 pacients, accuracy = 97,3% ; sensitivity = 94,6% and specificity = 98,6%. This study shows that the in house plasmid-based PCR is fasible for detection of Chlamydia trachomatis in male urine specimens. This test presented high accuracy, sensitivity and specificity, offering great potencial for the screening of men, an important reservoir of infection chlamydial for women.
62

InfecÃÃo Genital por Chlamydia trachomatis em mulheres jovens: prevalÃncia, fatores de risco e achados citopatolÃgicos e colposcÃpicos associados. / Chlamydia trachomatis genital infection in young women: prevalence, risk factors,cytological and colposcopic findings associated.

Rosiane Alves de Sousa Teles 20 November 2012 (has links)
A Chlamydia trachomatis (Ct) à a bactÃria de transmissÃo sexual mais comum em todo o mundo, apesar de existirem poucos dados sobre este agravo na populaÃÃo brasileira. O objetivo da pesquisa foi determinar a prevalÃncia da infecÃÃo por Ct, avaliando os fatores sÃciodemogrÃficos e achados clÃnicos, colposcÃpicos e citopatolÃgicos associados à ocorrÃncia desta infecÃÃo em mulheres jovens na periferia de Fortaleza. Foi realizado um estudo de corte transversal em 200 mulheres sexualmente ativas, com idade entre 12 e 25 anos, atendidas no perÃodo de agosto de 2011 a agosto de 2012, no ambulatÃrio de ginecologia geral do Hospital Distrital Gonzaga Mota â Barra do CearÃ. InformaÃÃes pessoais e dados do exame ginecolÃgico foram anotados em um questionÃrio e as pacientes submeteram-se à coleta de material da endocÃrvice para teste de captura hÃbrida II para Chlamydia trachomatis e para citologia oncÃtica convencional, seguido de colposcopia. Os dados foram analisados utilizando o software Graphpad Prism 5.0, procedendo-se a anÃlise descritiva e analÃtica utilizando o teste t de Student para as variÃveis nominais e o teste exato de Fisher para as variÃveis quantitativas. A prevalÃncia da infecÃÃo por Chlamydia trachomatis foi 15,5% (31/200) em mulheres adolescentes e adultas jovens. NÃo foi encontrada associaÃÃo entre a infecÃÃo estudada e as caracterÃsticas sÃciodemogrÃficas, hÃbitos sexuais, sinais e sintomas questionados, ectopia cilÃndrica e alteraÃÃes colposcÃpicas. Dentre as atipias citolÃgicas, o ASC-US esteve presente em 20,7% dos casos e 4,5% dos controles (p=0,0067, RR=3,452, IC=1,72-6,89), mostrando uma associaÃÃo positiva com a infecÃÃo clamidiana. A G. vaginalis foi encontrada em 54.8% das pacientes infectadas e em 30,7% das pacientes negativas (p=0,0133, RR=2,305. IC=1,21-4,39), mostrando uma relaÃÃo com a infecÃÃo estudada. Concluiu-se que a infecÃÃo por C. trachomatis teve uma prevalÃncia alta na populaÃÃo estudada, que nÃo houve associaÃÃo com fatores de risco sÃcio-demogrÃfico, biolÃgico, com achados clÃnicos e/ou colposcÃpicos. Houve associaÃÃo de ASC-US e G. vaginalis na citologia oncÃtica com a infecÃÃo estudada. / Chlamydia trachomatis (Ct) is the most common bacterial sexually transmitted infection worldwide, but there are few published dates about it in Brazil. The aim of this study was to determinate the prevalence of Chlamydia trachomatis infection and to assess the socialdemographic behavioral, clinical and cytopathological factors associated with this infection among adolescents and young women in a low-income area of Fortaleza - Brazil. A cross-sectional study was conducted in 200 sexually active women aged 12 to 25 years, from august 2011 to august 2012, in gynecology outpatient clinic of the General Hospital District Gonzaga Mota - Barra do CearÃ. Personal information and date of gynecogical examination were recorded in a questionnaire and the patients underwent collection of material from the endocervix to hybrid capture test for C. trachomatis and Pap test, followed by colposcopy. Data were analyzed using Graphpad Prism 5.0 software, proceeding to descriptive and analytical analysis using the Student t test for nominal variables and the Fisher exact test for quantitative variables. No association was found between infection and studied the socio-demographic characteristics, sexual habits, signs and symptoms questioned, cylindrical ectropion and colposcopic changes.Among the abnormal cytological atypia, ASC-US was presented in 20,7% of cases and 4,5% of controls (p=0,0067, RR=3,452, IC=1,72-6,89), with a positive association with the infection. G. vaginalis morphotype was identified in 54,8% of infected women and 30,7% of negative patients (p=0,0133, RR=2,305. IC=1,21-4,39), showing a relationship with the infection. It was concluded that infection with C. trachomatis had a high prevalence in the population studied, no association was observed with socio-demographic, biological and clinical findings and colposcopic changes. There was association of ASC-US and G. vaginalis in cytology with the infection studied.
63

Detecção de Chlamydia trachomatis em amostras de urina masculina por reação em cadeia da polimerase

Aquino, Alzira Resende do Carmo January 2005 (has links)
Infecções por Chlamydia trachomatis estão entre as mais freqüentes doenças sexualmente transmissíveis (DST) em todo o mundo, apresentando grande importância epidemiológica. A identificação deste patógeno pode ser difícil e um método de detecção baseado na amplificação de ácidos nucleicos é altamente desejável, por sua acurácia e rapidez. O presente estudo avaliou a acurácia, sensibilidade e especificidade de uma reação em cadeia da polimerase (PCR) in “house” em amostras de urina de homens com e sem sintomas de DST comparados a um teste comercial, o COBAS Amplicor CT/NG (Roche, Suiça). Foram utilizados primers específicos para amplificar um segmento do plasmídio críptico de C. trachomatis gerando um fragmento de 201 pb, cuja seqüência foi confirmada por clivagem enzimática e seqüenciamento automático. A especificidade analítica dos primers foi confirmada frente ao DNA de diferentes microrganismos patogênicos e não patogênicos da microbiota urogenital masculina. A detecção limite do DNA clamidial pela PCR in house após hibridização (Southern blot), foi de 1 pg. O COBAS Amplicor CT/NG foi considerado o teste de referência por ser automatizado e conter um programa de controle interno da reação para identificar inibição da DNA polimerase. Entre as 37 amostras testadas positivas para C. trachomatis pelo COBAS Amplicor, 33 foram confirmadas positivas pela PCR in house. Foram detectados inibidores da reação nas 4 amostras que apresentaram resultados falso-negativos, utilizando-se a técnica de contaminação da reação com o DNA clamidial (spiked) e um controle interno da reação com primers que amplificam a β-globina do DNA humano. Após congelamento e descongelamento para eliminar prováveis substâncias inibidoras lábeis, as 4 amostras foram re-testadas, resultando na positividade de mais 2 amostras, completando 35 amostras positivas pela PCR in house. Entre as 74 amostras testadas negativas para C. trachomatis pelo COBAS Amplicor, 72 foram confirmadas negativas pela PCR in house. Das 2 amostras prováveis falso-positivas, apenas 1 permaneceu positiva, após re-teste. Dos 111 pacientes analisados, 108 apresentaram resultados idênticos nos dois testes, o equivalente a uma acurácia = 97,3%, sensibilidade = 94,6% e especificidade = 98,6%. A alta sensibilidade e especificidade apresentada pela PCR in house, demonstra a possibilidade de triar e diagnosticar C. trachomatis em urina de homens, importante reservatório da infecção clamidial para as mulheres. / Chlamydia trachomatis infections are among the most commum sexually transmitted diseases and of great epidemiological importance world-wide. Identification of this pathogen can be difficult, and it is highly desirable to have a rapid and accurate nucleic acid amplification based detection method. The present study was designe to evaluate the accuracy, sensitivity and specificity of a in house plasmid-based polymerase chain reaction (PCR) and hybridization on first void urine specimens from symptomatic and asymptomatic men, compared with a commercial test the PCR COBAS Amplicor CT/NG (Roche, Switzerland), for detection of C. trachomatis (CT). Specific primers for the cryptic plasmid of C. trachomatis were designed to amplify a 201 bp fragment confirmed by enzymatic cleavage and automatic sequencing. The analytic specificity was determined by submitting to the intended protocol, the DNA of normal and pathogenic urogenital microbiota, the specific primers anneling was confirmed. The detection limit of the PCR and the Southern blot hibridization, was mesured in 1 pg of chlamydial DNA. The COBAS Amplicor CT/NG was considered the reference test, it contains a internal control (IC) programme to identify DNA polymerase inhibition. Among 37 positive specimens tested by COBAS Amplicor, 33 were confirmed positive by in house PCR and inhibitors of PCR were demonstrated in the 4 possibly false-negative samples performing DNA chlamydial spiking experiments and using a positive internal control of human β-globin DNA. The specimens were freezedthowed and re-tested to remove labile inhibitors, but 2 samples remained negative. Among 74 negative specimens by COBAS Amplicor, 72 were confirmed negative by in house PCR. The 2 problaby false-positive samples were re-tested and just one remained positive. The final results of the two tests were identical for 108 of the 111 pacients, accuracy = 97,3% ; sensitivity = 94,6% and specificity = 98,6%. This study shows that the in house plasmid-based PCR is fasible for detection of Chlamydia trachomatis in male urine specimens. This test presented high accuracy, sensitivity and specificity, offering great potencial for the screening of men, an important reservoir of infection chlamydial for women.
64

Análise da frequência de Papilomavírus humano e Chlamydia trachomatis em amostras anais de pacientes com lesão cervical

Silva, Keilla Maria Paz e 25 February 2014 (has links)
Submitted by Amanda Silva (amanda.osilva2@ufpe.br) on 2015-03-11T13:27:51Z No. of bitstreams: 2 DISSERTAÇÃO Keilla Maria Silva.pdf: 4228154 bytes, checksum: ea3da547f9bdeacfacd07ad7ced6d809 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-11T13:27:51Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO Keilla Maria Silva.pdf: 4228154 bytes, checksum: ea3da547f9bdeacfacd07ad7ced6d809 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2014-02-25 / CNPq / O Papilomavírus Humano (HPV) é um agente sexualmente transmissível que se destaca por infectar o trato anogenital, e devido à sua associação etiológica com uma grande variedade de carcinomas, encontra-se entre as mais importantes infecções sexualmente transmissíveis (IST) da atualidade. Acredita-se que a presença do vírus da imunodeficiência humana (HIV) e da Chlamydia trachomatis parecem favorecer a infectividade viral, proporcionando o surgimento de lesões que podem levar ao câncer. Desta forma, o presente trabalho teve por objetivo avaliar os genótipos do HPV presentes em amostras cervicais e anais, correlacionando com a infecção por Chlamydia trachomatis. Realizou-se um estudo incluindo 73 mulheres com idade entre 17 e 65 anos, atendidas no Hospital das Clínicas de Pernambuco (HC/UFPE) entre novembro de 2010 e fevereiro de 2013. As amostras foram obtidas e a extração do DNA foi realizada através de kits específicos. Posteriormente, os genótipos do HPV foram determinados pelo PapilloCheck® (GreinerBio-One) e a identificação da Chlamydia trachomatis por PCR em Tempo-Real. A prevalência do HPV no canal anal foi de 83,6%, estando associado com história de intercurso anal (p=0.0295) e infecção por HIV (p=0.0104). Infecção múltipla por HPV foi observada em 50,8% das pacientes, sendo o HPV44 o mais comum. Nos grupos HIV-positivo e HIV-negativo, o genótipo de alto risco mais frequente foi o HPV16, enquanto que HPV44 e o HPV43 foram os genótipos de baixo risco mais encontrados, respectivamente. A taxa de concordância entre os genótipos de HPV cervical e anal chegou a 52%. Apenas um paciente apresentou infecção por Chlamydia trachomatis em canal anal. Os resultados sugerem que o canal anal pode ter participação na infecção cervical funcionando como reservatório do vírus. Desta forma, o rastreamento dessas pacientes no serviço público de saúde pode favorecer um diagnóstico precoce, auxiliando os médicos no acompanhamento e prevenindo a evolução da infecção, principalmente em pacientes HIV-positivas.
65

Avaliação da relação entre clamídia e gonorreia em associação ao papilomavírus humano no desenvolvimento da neoplasia intraepitelial cervical e o carcinoma de colo uterino

Dantés, Andréa Gazzinelli Castro January 2017 (has links)
Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2018-05-25T12:56:00Z No. of bitstreams: 1 texto completo.pdf: 1186028 bytes, checksum: 22a128dd3187d1676fa8c422340d4483 (MD5) / Approved for entry into archive by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2018-05-25T12:56:14Z (GMT) No. of bitstreams: 1 texto completo.pdf: 1186028 bytes, checksum: 22a128dd3187d1676fa8c422340d4483 (MD5) / Approved for entry into archive by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2018-05-25T12:56:23Z (GMT) No. of bitstreams: 1 texto completo.pdf: 1186028 bytes, checksum: 22a128dd3187d1676fa8c422340d4483 (MD5) / Made available in DSpace on 2018-05-25T12:56:33Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1186028 bytes, checksum: 22a128dd3187d1676fa8c422340d4483 (MD5) Previous issue date: 2017 / Algumas infecções vaginais, como as vaginoses e a infecção por C. Trachomatis, foram associadas ao desenvolvimento de hipertrofia cervical e metaplasia escamosa, indicando uma possível relação com o HPV no desenvolvimento das NICs e carcinoma escamoso do colo uterino. Há na literatura alguns estudos sobre o assunto, ainda sem um consenso definitivo. Nesse sentido, este estudo teve como objetivo investigar a presença de C. trachomatis, N. gonorrhoeae e do papilomavírus humano e suas relações com as lesões cervicais em amostras de citologia cervical, casos e controles, obtidas no ambulatório de ginecologia, do Centro de Especialidades Médicas da Santa Casa de Belo Horizonte. A detecção e genotipagem do HPV, além da detecção da C. trachomatis e N. gonorrhoeaea foram realizadas pela técnica de PCR. Das 186 amostras obtidas, 79 eram o grupo controle e 107 eram do grupo dos casos, portadoras de lesão cervical (38 baixo grau,44 alto grau e 25 CCE). A prevalência de HPV foi 67,7%, da clamídia 19,9% e da gonorreia 3,6%. Os genótipos do HPV mais encontrados foram o HPV 16, 59 e 45. A infecção por mais de um genótipo viral teve associação positiva com a presença de lesões cervicais em geral, e especificamente com lesões de alto grau e câncer. Não houve associação com lesões de baixo grau. As infecções por clamídia e gonorréia, mesmo em associação com HPV, não resultaram em aumento de alterações cervicais. A infecção por N. gonorrhoeaea teve 100% de coinfecção com C.trachomatis, com OR de 5,8 (p<0,0001, 95% IC 4,21-7,99). / Some vaginal infections, such as vaginosis and chlamydia, have been associated with the development of cervical hypertrophy and squamous metaplasia, indicating a possible relationship with HPV in the development of CINs and squamous carcinoma of the cervix. There are some studies in the literature on the subject, still without a definitive consensus. The objective of this study was to investigate the presence of chlamydia trachomatis, neisseria gonorrhoeae and human papillomavirus and their relationship with cervical lesions in cervical cytology samples, cases and controls obtained from Santa Casa Medical Center in Belo Horizonte. HPV detection and genotyping in addition to the detection of C. trachomatis and N. gonorrhoeae were performed by the PCR technique. Of the 186 samples obtained, 79 were the control group and 107 were from the group of cases, with cervical lesions (38 low grade, 44 high grade and 25 CEC). The prevalence of HPV was 67.7%, chlamydia 19.9% and gonorrhea 3.6%. The most common HPV genotypes were HPV 16, 59 and 45. Infection with more than one viral genotype was positively associated with the presence of cervical lesions in general, and specifically with high grade lesions and cancer. There was no association with low grade lesions. Chlamydia and gonorrhea infections, even in association with HPV, did not result in increased cervical changes. N. gonorrhoeaea infection had 100% coinfection with C.trachomatis, with OR of 5.8 (p <0.0001, 95% CI 4.21-7.99). / Não foi apresentado título em inglês. Não foi localizado o cpf do autor.
66

Pathogenic Interplay Between Chlamydia Trachomatis and Neisseria Gonorrhoeae That Influences Management and Control Efforts—More Questions Than Answers?

Leonard, Cory Ann, Schoborg, Robert V., Low, Nicola, Unemo, Magnus, Borel, Nicole 15 September 2019 (has links)
Purpose of Review: To emphasize key gaps in knowledge impacting efforts to control single infection and co-infections with Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG), the most common bacterial sexually transmitted infections (STIs) worldwide. Recent Findings: Clinical and epidemiological studies describe gaps in understanding about female rectal CT infection, screening effectiveness, pelvic inflammatory disease, and influence of the microbiome. For NG, gaps in knowledge include factors increasing incidence in men who have sex with men, correlations between treatment and antibiotic resistance, the role of pharyngeal infection, and microbiome influence. CT/NG co-infections are poorly understood, and adequate models to explore pathophysiological consequences of co-infection urgently needed. The sole existing CT/NG co-infection mouse model showed that CT/NG interactions in vivo modulate host response and NG load/shedding—encouraging further consideration of this model and potential alternatives. Summary: We stress key challenges in controlling these important STIs. Appropriate, quality-assured animal models are essential to improve understanding of the pathogenic interplay in CT/NG co-infections.
67

The Host Adherens Junction Molecule Nectin-1 Is Degraded by Chlamydial Protease-Like Activity Factor (CPAF) in Chlamydia Trachomatis-Infected Genital Epithelial Cells

Sun, Jingru, Schoborg, Robert V. 01 January 2009 (has links)
Nectin-1 is an adhesion protein implicated in the organization of adherens junctions and tight junctions in epithelial cells. Previous studies in our laboratory demonstrated that nectin-1 accumulation was significantly decreased in Chlamydia trachomatis-infected HeLa cells. In the present study, Western blot analyses indicated that nectin-1 down-regulation was C. trachomatis concentration-dependent. The half-life of nectin-1 was also greatly diminished in C. trachomatis-infected cells compared to that observed in mock-infected cells, indicating that nectin-1 was likely down-regulated post-translationally. The chlamydia-secreted protease CPAF is known to degrade several important host proteins; CPAF expression within infected cells correlated with the time-dependent cleavage of nectin-1. Notably, CPAF proteolytic activity is inhibited by lactacystin but not by the proteosome inhibitor MG132. In vivo inhibition experiments demonstrated that nectin-1 down-regulation was blocked by lactacystin exposure. In contrast, MG132 had no effect. Finally, cell-free cleavage assays demonstrated that functional recombinant GST-CPAFwt protein degrades nectin-1. This degradation was blocked by lactacystin, as previously observed in vivo. Collectively, these results indicate that nectin-1 is degraded by CPAF in C. trachomatis-infected cells, a novel strategy that chlamydiae may use to aid their dissemination.
68

The identification and characterization of novel persistence genes in chlamydia trachomatis

Muramatsu, Matthew Kazuyuki 30 November 2016 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Chlamydia trachomatis is an obligate intracellular bacterial pathogen that can infect the eyes, genital tract, and disseminate to lymph nodes in humans. Many C. trachomatis infections are clinically asymptomatic and can become chronic if left untreated. When humans are infected with C. trachomatis, a cytokine that is produced is interferon-gamma (IFN-γ). In vitro, IFN-γ stimulates expression of the host enzyme indoleamine 2,3-dioxygenase. This enzyme converts free intracellular tryptophan to N-formylkynurenine. Tryptophan starvation induces C. trachomatis to enter a viable-but-nonculturable state termed persistence, which has been proposed to play a key role in chronic Chlamydial disease. To circumvent host induced tryptophan depletion, urogenital strains of C. trachomatis encode a functional tryptophan synthase (TS). TS synthesizes tryptophan from indole and serine, allowing Chlamydia to reactivate from persistence. Transcriptomic analysis revealed C. trachomatis differentially regulates hundreds of genes in response to tryptophan starvation. However, genes that mediate entry, survival, and reactivation from persistence remain largely unknown. Using a forward genetic screen, we identified six Susceptible to IFN-γ mediated Persistence (Sip) mutants that have diminished capacities to reactivate from persistence with indole. Mapping the deleterious persistence alleles in three of the Sip mutants revealed that only one of the mutants had a mutation in TS. The two other Sip mutants mapped had mutations in CTL0225, a putative integral membrane protein, and CTL0694, a putative oxidoreductase. Neither of these genes plays a known role in tryptophan synthesis. However, amino acid (AA) competitive inhibition assays suggest that CTL0225 may be involved in the transport of leucine, isoleucine, valine, cysteine, alanine, and serine. Additionally, metabolomics analysis indicates that all free amino acids are depleted in response to IFN-γ, making this amino acid transporter essential during persistence. Taken together we have identified two new chlamydial persistence genes that may play a role in chronic chlamydial disease.
69

Subversion of Host Genome Integrity by Human Herpesvirus 6 and \(Chlamydia\) \(trachomatis\) / Störung der Integrität des Wirts Genoms durch das Human Herpesvirus 6 und \(Chlamydia\) \(trachomatis\)

Gulve, Nitish January 2019 (has links) (PDF)
Ovarian cancer is one of the most common gynecological malignancies in the world. The prevalence of a microbial signature in ovarian cancer has been reported by several studies till date. In these microorganisms, Human herpesvirus 6 (HHV-6) and Chlamydia trachomatis (C.tr) are especially important as they have significantly high prevalence rate. Moreover, these pathogens are directly involved in causing DNA damage and thereby disrupting the integrity of host genome which is the underlying cause of any cancer. This study focuses on how the two pathogens, HHV-6 and C. trachomatis can affect the genome integrity in their individual capacities and thereby may drive ovarian epithelial cells towards transformation. HHV-6 has unique tendency to integrate its genome into the host genome at subtelomeric regions and achieve a state of latency. This latent virus may get reactivated during the course of life by stress, drugs such as steroids, during transplantation, pregnancy etc. The study presented here began with an interesting observation wherein the direct repeat (DR) sequences flanking the ends of double stranded viral genome were found in unusually high numbers in human blood samples as opposed to normal ratio of two DR copies per viral genome. This study was corroborated with in vitro data where cell lines were generated to mimic the HHV-6 status in human samples. The same observation of unusually high DR copies was found in these cell lines as well. Interestingly, fluorescence in situ hybridization (FISH) and inverse polymerase chain reaction followed by southern blotting showed that DR sequences were found to be integrated in nontelomeric regions as opposed to the usual sub-telomeric integration sites in both human samples and in cell lines. Sanger sequencing confirmed the non-telomeric integration of viral DR sequences in the host genome. Several studies have shown that C. trachomatis causes DNA damage and inhibits the signaling cascade of DNA damage response. However, the effect of C. trachomatis infection on process of DNA repair itself was not addressed. In this study, the effect of C. trachomatis infection on host base excision repair (BER) has been addressed. Base excision repair is a pathway which is responsible for replacing the oxidized bases with new undamaged ones. Interestingly, it was found that C. trachomatis infection downregulated polymerase β expression and attenuated polymerase β- mediated BER in vitro. The mechanism of the polymerase β downregulation was found to be associated with the changes in the host microRNAs and downregulation of tumor suppressor, p53. MicroRNA-499 which has a binding site in the polymerase β 3’UTR was shown to be upregulated during C. trachomatis infection. Inhibition of miR-499 using synthetic miR-499 inhibitor indeed improved the repair efficiency during C. trachomatis infection in the in vitro repair assay. Moreover, p53 transcriptionally regulates polymerase β and stabilizing p53 during C. trachomatis infection enhanced the repair efficiency. Previous studies have shown that C. trachomatis can reactivate latent HHV-6. Therefore, genomic instability due to insertions of unstable ‘transposon-like’ HHV-6 DR followed by compromised BER during C. trachomatis infection cumulatively support the hypothesis of pathogenic infections as a probable cause of ovarian cancer / Diese Studie fokussiert sich darauf, wie die beiden Pathogene HHV-6 und C. trachomatis die Genom Integrität beeinflussen und dadurch die Transformation ovarialer Epithelzellen zu Tumorzellen antreiben können. Das latente Virus HHV-6 kann sich in Subtelomer-Regionen des Genoms integrieren und zu jeder Lebensphase (z.B. durch Stress oder Pharmaka) reaktiviert werden. Zu Beginn dieser Studie wurde die Beobachtung gemacht, dass in menschlichen Blutproben eine ungewöhnlich hohe Anzahl an sogenannten direct repeat Sequnzen, die die Enden des doppelsträngigen Virus Genoms flankieren, aufwiesen. Bestätigt wurde diese Beobachtung durch in vitro Daten, wofür Zelllinien generiert wurden, um den HHV-6 Wert in menschlichen Proben zu imitieren. Außerdem konnte durch Sanger Sequenzierung die Integration der viralen DR Sequenzen außerhalb von Telomer Regionen in das Genom nachgewiesen werden. Verschiedene Studien konnten zeigen, dass C. trachomatis DNA Schäden verursacht und die Signal Kaskade von Antworten auf DNA-Schäden inhibiert. Bisher wurde die Auswirkung einer C. trachomatis Infektion auf den Prozess der DNA Reparatur selbst noch nicht behandelt. In dieser Studie wird die Auswirkung einer C. trachomatis Infektion auf Basen-Exzisionsreparatur (BER) thematisiert. Interessanterweise wurde herausgefunden, dass während einer C. trachomatis Infektion die Expression von Polymerase β herunterreguliert ist und dadurch die Polymerase β-vermittelte Basen-Exzisionsreparatur in vitro gestoppt wird. Diese Herunterregulierung konnte mit einer verminderten Expression des Tumorsuppressor p53 assoziiert werden. Darüber hinaus reguliert p53 auf transkriptioneller Ebene Polymerase β und eine Stabilisierung von p53 während einer C. trachomatis Infektion verbesserte die Reparatur-Effizienz. Vorangegangene Studien haben außerdem gezeigt, dass C. trachomatis die latente Form von HHV-6 reaktivieren kann. Deshalb unterstützt die genomische Instabilität aufgrund einer Insertion von HHV-6 DR, gefolgt von komprimierter BER während einer C. trachomatis Infektion, zunehmend die Hypothese, dass eine pathogene Infektion ein vermutlicher Auslöser von Eierstockkrebs sein könnte.
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Maraviroc, Celastrol and Azelastine Alter Chlamydia Trachomatis Development in HeLa Cells

Kuratli, Jasmin, Leonard, Cory Ann, Nufer, Lisbeth, Marti, Hanna, Schoborg, Robert, Borel, Nicole 12 November 2020 (has links)
Introduction. Chlamydia trachomatis (Ct) is an obligate intracellular bacterium, causing a range of diseases in humans. Interactions between chlamydiae and antibiotics have been extensively studied in the past. Hypothesis/Gap statement: Chlamydial interactions with non-antibiotic drugs have received less attention and warrant further investigations. We hypothesized that selected cytokine inhibitors would alter Ct growth characteristics in HeLa cells. Aim. To investigate potential interactions between selected cytokine inhibitors and Ct development in vitro. Methodology. The CCR5 receptor antagonist maraviroc (Mara; clinically used as HIV treatment), the triterpenoid celastrol (Cel; used in traditional Chinese medicine) and the histamine H1 receptor antagonist azelastine (Az; clinically used to treat allergic rhinitis and conjunctivitis) were used in a genital in vitro model of Ct serovar E infecting human adenocarcinoma cells (HeLa). Results. Initial analyses revealed no cytotoxicity of Mara up to 20 µM, Cel up to 1 µM and Az up to 20 µM. Mara exposure (1, 5, 10 and 20 µM) elicited a reduction of chlamydial inclusion numbers, while 10 µM reduced chlamydial infectivity. Cel 1 µM, as well as 10 and 20 µM Az, reduced chlamydial inclusion size, number and infectivity. Morphological immunofluorescence and ultrastructural analysis indicated that exposure to 20 µM Az disrupted chlamydial inclusion structure. Immunofluorescence evaluation of Cel-incubated inclusions showed reduced inclusion sizes whilst Mara incubation had no effect on inclusion morphology. Recovery assays demonstrated incomplete recovery of chlamydial infectivity and formation of structures resembling typical chlamydial inclusions upon Az removal. Conclusion. These observations indicate that distinct mechanisms might be involved in potential interactions of the drugs evaluated herein and highlight the need for continued investigation of the interaction of commonly used drugs with Chlamydia and its host.

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