No description available.

Mycoplasma hyopneumoniae é uma bactéria pertencente à classe Mollicutes, sendo o agente etiológico da pneumonia enzoótica suína e o agente primário do complexo de doenças respiratórias de suínos (CDRS). A sinal-peptidase I (SPase I) é uma endopeptidase de membrana que cliva os peptídeos-sinal (PS) de proteínas transportadas pelo sistema geral de secreção. A SPase I do M. hyopneumoniae (MhSPase I) é codificada pela sequência de DNA codificadora (CDS) sipS, presente nas 3 linhagens da espécie com genomas já sequenciados. Este trabalho tem como objetivo caracterizar funcional e imunologicamente a MhSPase I, assim como investigar a sua relação com a virulência da bactéria. Foi demonstrado que sipS é parte de um operon, sendo cotranscrita com outras 4 CDSs. A CDS sipS foi clonada e a MhSPase I recombinante (rMhSPase I) foi expressa em Escherichia coli. A rMhSPase I mostrou-se altamente imunogênica para camundongos e seu caráter antigênico foi confirmado para suínos. A MhSPase I apresentou expressão diferencial em linhagens patogênicas e não patogênicas de M. hyopneumoniae corroborando a ideia de que essa enzima é um fator de virulência da bactéria. Análises de sequências de aminoácidos evidenciaram que a MhSPase I tem baixa identidade com enzimas ortólogas de outras espécies de micoplasmas e de bactérias relacionadas ao CDRS. O potencial sorodiagnóstico da rMhSPase I foi demonstrado em um ELISA. Predições in silico de possíveis PSs clivados pela MhSPase I indicaram que proteínas hipotéticas e proteínas de membrana, incluindo adesinas, seriam substratos da enzima. Ensaios de atividade in vitro com PSs sintéticos derivados de predições in silico, contudo, não foram conclusivos. Estudos futuros deverão elucidar o papel da SPase I na exportação de proteínas em M. hyopneumoniae e explorar o potencial da enzima como antígeno vacinal ou diagnóstico. / Mycoplasma hyopneumoniae is a bacterium that belongs to the Mollicutes class, being the etiological agent of porcine enzootic pneumoniae and one of the primary agents of the porcine respiratory disease complex (PRDC). Signal peptidase I (SPase I) is a membrane-bound endopeptidase that cleaves the signal peptide (SP) of proteins exported by the general secretory pathway. The M. hyopneumoniae SPase I (MhSPase I) is coded by the sipS gene in all of the three M. hyopneumoniae genomes sequenced. The aims of this work are to functional and immunologically characterize the MhSPase I and to investigate its relation with the virulence of the bacterium. The sipS coding DNA sequence (CDS) was demonstrated to be part of an operon, being co-transcribed along with 4 other CDSs. The sipS CDS was cloned and the recombinant MhSPase I (rMhSPase I) was expressed in Escherichia coli. The rMhSPase I was highly immunogenic for mice and the antigenicity for pigs was demonstrated. The observed differential expression of MhSPase I between pathogenic strains and one non pathogenic strain of M. hyopneumoniae corroborates the notion of MhSPase I as a virulence factor. Amino acid sequence analyses of MhSPase I and SPases I from other Mycoplasma and PRDC bacteria evidenced low conservation between these enzymes. The potential serodiagnosis application of rMhSPase I was demonstrated by an ELISA. In silico predictions of putative SPs cleaved by MhSPase I were performed, indicating that hypothetical and membrane proteins, including adhesins, have cleavable SPs. In vitro cleavage assays of rMhSPase I were developed with synthetic SPs, but the results were not conclusive. Further studies should elucidate the role of SPase I in the exportation of proteins in M. hyopneumoniae and the putative application of MhSPase I as an antigen for vaccination and diagnosis.

Bacterial and fungal culturing was conducted on samples taken from the vaginal fornix of 106 cows, of which 42 had vaginitis and 64 had normal vaginas. The diagnosis of vaginitis and non-vaginitis samples was determined by histologic examination. Aerobic, anaerobic, and microaerophilic cultures were done. In addition, cultures were performed for Campylobacter sp., Ureaplasma sp., Mycoplasma sp., Tritrichomonas foetus, and fungi. All 106 samples contained mixed aerobic bacterial cultures. The more frequent aerobic isolates included Acinetobacter lwoffii, Arcanobacterium pyogenes, Escherichia coli, Corynebacterium spp., and Streptococcus spp. These organisms were isolated from both groups of cows, but more frequently from the vaginitis group. Anaerobic isolates included Peptostreptococcus spp., Prevotella spp., and Fusobacterium spp. The fungal isolates included Aspergillus sp., Mucor sp., and Penicillium sp.

Bacterial and fungal culturing was conducted on samples taken from the vaginal fornix of 106 cows, of which 42 had vaginitis and 64 had normal vaginas. The diagnosis of vaginitis and non-vaginitis samples was determined by histologic examination. Aerobic, anaerobic, and microaerophilic cultures were done. In addition, cultures were performed for Campylobacter sp., Ureaplasma sp., Mycoplasma sp., Tritrichomonas foetus, and fungi. All 106 samples contained mixed aerobic bacterial cultures. The more frequent aerobic isolates included Acinetobacter lwoffii, Arcanobacterium pyogenes, Escherichia coli, Corynebacterium spp., and Streptococcus spp. These organisms were isolated from both groups of cows, but more frequently from the vaginitis group. Anaerobic isolates included Peptostreptococcus spp., Prevotella spp., and Fusobacterium spp. The fungal isolates included Aspergillus sp., Mucor sp., and Penicillium sp.

Thesis (Ph. D.)--University of Missouri--Columbia, 2003. / "May 2003." Typescript. Vita. Includes bibliographical references (leaves 156-175).

No description available.

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1967. / Bibliography: leaves [121]-123. / ix, 123 l graphs, tables

Proefschrift Universiteit van Amsterdam. / Auteursnaam op omslag: J. Wendelien Dorigo-Zetsma. Met bibliogr., lit. opg. - Met samenvatting in het Nederlands.

Thesis (M.Sc. in Microbiology) -- Mahidol University, 1976.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1974. / Typescript. Vita. Description based on print version record. Includes bibliographical references.