In vitro liver models that closely mimic the in vivo microenvironment are central for understanding hepatic functions and intercellular communication processes. Bottom-up shotgun proteomic analysis of the hepatic cells can lend insight into such processes. This technique employs liquid chromatography-tandem mass spectrometry (LC-MS/MS) for relative quantification of protein abundances by measuring intensities of their corresponding peptides. Organotypic 3D liver models have been developed in our laboratory that consist of hepatocytes and liver sinusoidal endothelial cells (LSECs) separated by a polyelectrolyte multilayer (PEM), which serves as a mimic for the Space of Disse. Each component within these models is easily separable allowing for systematic evaluation of the cells and PEMs. In this study, proteomes of hepatocytes from PEM containing models, cultured with and without LSECs, were compared to those from monolayers. Changes in core metabolism were evaluated among all culture conditions. Overall, all cultures were ketogenic and performed gluconeogenesis. The presence of the PEM led to increases in proteins associated with mitochondrial-based β-oxidation and peroxisomal proteins. The PEMs also limited production of structural proteins, which are linked to dedifferentiation of hepatocytes, suggesting that cell-ECM interactions are essential for maintenance of their liver-like state. The presence of LSECs increased levels of carboxylesterases and other phase I and phase II detoxification enzymes suggesting that intercellular signaling mediates enzyme abundance. Taken together, these results suggest that the cell-cell (from the LSECs) and cell-ECM (from the PEMs) interactions exert different, yet crucial effects, and both are required for the preservation of metabolic liver functions and differentiated phenotypes. Changes in the PEMs as a result of cell culture were also evaluated but exhibited minimal differences at this time point. Proteomes of LSECs monolayers were also characterized. Enzymes related to the metabolism of amino acids, lipids, oxidative phosphorylation and phase I and phase II detoxification processes were all identified in LSECs monolayers highlighting their role in these processes. Characterization of 3DHL LSECs was not possible due to ion suppression resulting from the presence of excess contaminant proteins. Nonetheless, this study provides a foundation in which LSECs from 3D liver models can be compared against in future studies. / Ph. D.

A detailed study has been made of the distribution of lead on a public shotgun range in the George Washington-Jefferson National Forests in southwestern Virginia. Sampling of more than 100 sites has yielded data on the distribution pattern of the lead shot. Since opening in 1993 through 2000, 11.1 metric tons of lead has accumulated over an area 220 by 300 m (66,000 m2) with an average rate of accumulation of 1.4 metric tons per year. More than 85 % of the total dispersed lead lies scattered in the forest that surrounds the approximately 60 by 60 m cleared shooting surface. Lead is irregularly distributed because of the use of stationary targets and the general trajectory of launched clay targets. Maximum concentrations occur at distances of about 28 m about 80 m, and at about 180 m reach a maximum value of more than 5000 g per m2. Significant amounts of fine particulate lead, generated during shooting and as a result of impact occur close to the shooting box but absent at distances beyond 50 m. / Master of Science

The use of antibiotics in dairy cattle has the potential to stimulate the development and subsequent fecal dissemination of antibiotic resistance genes (ARGs) in bacteria. The objectives were to use metagenomic techniques to evaluate the effect of antibiotic treatment on ARG prevalence in the fecal microbiome of the dairy cow and to determine the temporal excretion pattern of ARGs. Twelve Holstein cows were assigned to one of four antibiotic treatments: control, pirlimycin, ceftiofur, or cephapirin. Fecal samples were collected on d -1, 1, 3, 5, 7, 14, 21, and 28. Samples were freeze-dried and subjected to DNA extraction followed by Illumina paired-end HiSeq sequencing and quantitative polymerase chain reaction (qPCR). Illumina sequences were analyzed using MG-RAST and the Antibiotic Resistance Gene Database (ARDB) via BLAST. Abundance of ampC, ermB, tetO, tetW, and 16S rRNA genes were determined using qPCR. All data were statistically analyzed with PROC GLIMMIX in SAS. Antibiotic treatment resulted in a shift in bacterial cell functions. Sequences associated with 'resistance to antibiotics and toxic compounds' were higher in ceftiofur-treated cows than control cows. Ceftiofur-treated cows had a higher abundance of 𝛽-lactam and multidrug resistance sequences than control cows. There was no effect of treatment or day on fecal tetO and ermB excretion. The relative abundances of tetW and ampC were higher on d 3 post-treatment than d 5 and d 28. In conclusion, antibiotic use in dairy cattle shifted bacterial cell functions and temporarily increased antibiotic resistance in the fecal microbiome. / Master of Science

Leptospirose é uma doença infecciosa emergente cujos agentes etiológicos são espécies patogênicas do gênero Leptospira. Leptospiras patogênicas possuem inúmeros genes específicos codificando proteínas com funções desconhecidas, sugerindo que as leptospiras apresentam fatores de virulência únicos. Adesinas bacterianas são importantes fatores de virulência e, assim, a identificação de adesinas conservadas em espécies patogênicas de Leptospira pela construção de bibliotecas genômicas expostas na superfície de bacteriófagos (shotgun phage display), seguida por seleção em células e/ou componentes da matriz extracelular (biopanning), pode revelar novos antígenos e alvos para o tratamento e prevenção da leptospirose. Bibliotecas foram construídas com o DNA genômico de L. interrogans fragmentado e o fagomídeo pG8SAET, sendo testadas algumas abordagens para clonagem como a ligação entre extremidades cegas (blunt-end) e técnicas baseadas em ligação entre extremidades coesivas, incluindo a obtenção de ORESTES e a utilização de adaptadores em grampo. Apesar de serem encontradas algumas limitações, a clonagem por ligação blunt-end se mostrou a mais eficiente para a construção de bibliotecas, sendo adotada para a construção de três bibliotecas em maior escala. A seleção de novas possíveis adesinas a partir das bibliotecas construídas foi realizada em células eucarióticas através da metodologia BRASIL. A primeira biblioteca (BBT1) exibiu 106 clones totais, a partir da qual foram selecionados quatro proteínas em fase apenas com a proteína VIII do fago (pVIII). No entanto, nenhuma delas seria exposta por programas de predição na bactéria. Outras duas bibliotecas foram construídas (BBT2 e BBT3), as quais obtiveram um número ideal de clones para uma ampla cobertura do genoma (>2x107 clones). Por apresentar maior proporção de clones válidos, a BBT2 foi utilizada para a seleção de adesinas, resultando em onze clones em fase com pVIII e/ou sequência sinal do fago. Análises por programas de predição revelaram três proteínas hipotéticas, denominadas LepA962, LepA069 e LepA388, as quais poderiam estar expostas ou ser secretadas pela bactéria, sugerindo uma possível função de adesina. O estudo da proteína LepA388 levou ao reconhecimento de outras doze proteínas semelhantes e pertencentes a uma família paráloga contendo um domínio denominado DUF_61, motivo de função desconhecida presente em proteínas compartilhadas somente entre as espécies patogênicas mais virulentas de Leptospira. Por esta razão, a proteína LepA388 foi a mais estudada. A clonagem de três porções da proteína (LepA388P, LepA388NR e LepA388F) para expressão heteróloga resultou em proteínas recombinantes insolúveis e, considerando a riqueza em resíduos de cisteína presente em sua estrutura, não foi possível renaturá-las adequadamente. Diante dos obstáculos encontrados, apenas a porção contendo a sequência apresentada pelo fago (LepA388P) foi utilizada para obtenção de antissoros em camundongos, os quais apresentaram altos títulos, demonstrando a alta imunogenicidade da proteína LepA388P. O reconhecimento de proteínas nativas da família paráloga DUF_61 em extratos de diferentes sorovares de Leptospira não foi observado, assim como sua expressão in vitro a partir de bactérias em diferentes condições de cultivo. Estudos adicionais sobre a expressão in vivo e funções dos membros desta família são necessários para uma compreensão mais ampla de seu papel na biologia de leptospiras e, possivelmente, na patogênese da leptospirose. / Leptospirosis is an emerging infectious disease whose etiologic agents are pathogenic species of the genus Leptospira. Pathogenic leptospires have countless specific genes encoding proteins with unknown functions, suggesting that leptospires have unique virulence factors. Bacterial adhesins are important virulence factors and so the identification of conserved adhesins in pathogenic Leptospira species from shotgun phage display libraries, followed by selection (biopanning) in cells and/or extracellular matrix components, can reveal new antigens and strategies for leptospirosis treatment and prevention. Libraries were constructed using fragmented genomic DNA from L. interrogans and pG8SAET phagemid vector. Cloning approaches included blunt-end ligation and techniques based in cohesive-end ligation, such as ORESTES strategy and hairpin linkers. Despite some limitations, cloning by blunt-end ligation was the most efficient for library construction, being adopted for the construction of three libraries on a larger scale. Selection of new possible adhesins was performed by biopanning of the libraries in eukaryotic cells through BRASIL methodology. The first library called BBT1 exhibited approximately 106 total clones, and its biopanning resulted in four proteins fused to phage protein VIII, but none of them were expected to be exposed by the bacteria. Other libraries were built (BBT2 and BBT3) which reached the expected number of clones to obtain a larger genome representation (> 2x107 clones). Since it showed the highest proportion of positive clones, BBT2 was selected to perform a second biopanning, resulting in eleven proteins fused to phage protein VIII and/or signal peptide. In silico analysis revealed three hypothetical proteins, named LepA962, LepA069 and LepA388, that would be exposed or secreted by the bacteria, suggesting a possible adhesin function. The study of LepA388 protein led to the recognition of twelve other similar proteins belonging to a paralogous family that contains a domain called DUF_61, domain of unknown function that is present in proteins shared only among the most virulent pathogenic species of Leptospira. For this reason, the LepA388 protein was the most studied. The cloning of three portions of the protein (LepA388P, LepA388NR and LepA388F) for heterologous expression resulted in insoluble recombinant proteins, and given the presence of many cysteine residues in its structure, it was not possible to renature them appropriately. In face of the imposed obstacles, only the portion containing the sequence presented by the bacteriophage (LepA388P) was used to obtain antisera in mice, which showed high titers, demonstrating the high immunogenicity of the protein LepA388P. Recognition of native DUF_61 paralogous family proteins in extracts from distinct Leptospira serovars was not observed, as well as its in vitro expression from bacteria cultured in different conditions. Additional studies on the in vivo expression and functions of members of this family are needed for a broader understanding of their role in leptospiral biology and possibly in the pathogenesis of leptospirosis.

Em Leptospira interrogans algumas proteínas com capacidade de ligação aos componentes de matriz extracelular foram identificadas e, em sua maioria, são fatores de virulência. Phage display é considerada uma técnica poderosa na identificação de novos ligantes, inclusive de moléculas adesinas, importantes no primeiro estágio de infecção do hospedeiro. A técnica de shotgun phage display foi utilizada visando à obtenção de ligantes à células de mamíferos. Quatro bibliotecas, por inserção de fragmentos aleatórios obtidos por sonicação do DNA de L. interrogans nos fagomídeos pG8SAET (BBT1 e BBT2) e pG3DSS (BBT5 e BBT6), foram construídas. As bibliotecas BBT1 e BBT5 contém insertos maiores e as BBT2 e BBT6 contém insertos menores, com tamanhos médios de 1500 pb e 350 pb, respectivamente. Após ensaio de panning da BBT5 contra células de mamíferos e soro fetal bovino, as sequências de clones selecionados foram analisadas quanto a orientação correta e se a fusão estava em fase com a proteína pIII. As proteínas codificadas pelos genes LIC11719, LIC10769, LIC13143 e LIC12976 foram selecionadas com estas características. Os genes que codificam a LIC12976, LIC10768, LIC10769 e LIC13418, tiveram sua conservação avaliada em diferentes sorovares da espécie patogênica L. interrogans e no sorovar Patoc da espécie de vida livre L. biflexa. As proteínas LIC12976 (selecionada pela técnica de phage display) e LIC13418 (selecionada por ferramentas de bioinformática) tiveram suas sequências amplificadas por PCR, clonadas em pGEM T easy, subclonadas em vetor de expressão pAE e expressas na fração celular correspondente ao corpúsculo de inclusão em E. coli BL21 (DE3) Star pLysS e E. coli BL21 SI, respectivamente. Após renaturação e purificação destas proteínas por cromatografia de afinidade a metal bivalente, um grupo de cinco animais BALB/c fêmeas foi imunizado. Ambas as proteínas se mostraram imunogênicas com títulos dos soros policlonais 1:256000 e 1:512000, respectivamente. Em ensaio de Western Blot os soros foram específicos no reconhecimento das proteínas recombinantes e as proteínas nativas foram verificadas em extratos de sorovares patogênicos de L. interrogans. Em ensaios de adesão, as proteínas recombinantes aderiram às células A31, LLC-PK1 e Vero e especificamente à laminina. Em ensaios de interferência em células usando laminina houve um aumento da adesão das proteínas recombinantes, o que pode ser explicado pela ligação da laminina às células e uma maior ligação das LICs estudadas. Em ensaio de localização celular usando imunofluorescência e microscopia eletrônica, foi observado que ambas as proteínas se encontram na superfície da L. interrogans. No experimento de desafio animal, a LIC12976 e a LIC13418 não se mostraram protetoras. Este trabalho contribuiu para a identificação das novas adesinas LIC13418 e LIC12976 que podem participar da virulência de leptospiras patogênicas envolvendo a primeira etapa da infecção na interação patógeno-hospedeiro / In Leptospira interrogans, proteins capable to bind to extracellular matrix components have been identified and most of them are important virulence factors. Phage display is a powerful technique to identify new ligands, including adhesin molecules that are important in the first stage of host infection. A shotgun phage display technique was used in order to obtain cell ligands. Four libraries were constructed by inserting random fragments obtained by sonication of L. interrogans DNA into phagemids pG8SAET (BBT1 and BBT2) and pG3DSS (BBT5 and BBT6). The libraries BBT1 and BBT5 contain larger inserts and BBT2 and BBT6 contain smaller inserts, with 1500 bp and 350 bp average sizes, respectively. After panning of BBT5 against mammalian cells and bovine fetal serum, the sequences of selected clones were analyzed for correct orientation and fusion with pIII protein. The proteins encoded by genes LIC11719, LIC10769, LIC13143 and LIC12976 were selected. The genes LIC12976, LIC10768, LIC10769 and LIC13418 were evaluated for their conservation in different pathogenic serovars of L. interrogans and free-living L. biflexa serovar Patoc. Proteins LIC12976 (selected by phage display technique) and also LIC13418 that was selected by bioinformatic tools, were amplified by PCR, cloned into pGEM T easy, subcloned into expression vector pAE and expressed in cellular fraction corresponding to the inclusion body in E. coli BL21 (DE3) Star pLysS and E. coli BL21 SI, respectively. After protein renaturation protocol and purification by affinity chromatography, a group of five BALB/c mice was immunized with the purified proteins. Both proteins were shown to be immunogenic with 1:256000 and 1:512000 polyclonal sera titers, respectively. In Western blot the sera were specific to recognize recombinant proteins and native proteins were detected in pathogenic L. interrogans serovars extracts. In binding assays, recombinant proteins bind to A31, LLC-PK1 and Vero cells and specifically to laminin. In interference cell assay using laminin there was an increase of recombinant protein bindings, which can be explained by the laminin binding to cells and further binding of the recombinant LICs. In cellular localization assay using immunofluorescence and electron microscopy, it was observed that both are surface proteins of L. interrogans. In the animal challenge, the LIC12976 and LIC13418 were not protective. As a whole, this work contributed to the identification of LIC12976 and LIC13418 as new adhesins and they can participate in the virulence of pathogenic Leptospira in the first stage of host pathogen interaction.

Em Leptospira interrogans algumas proteínas com capacidade de ligação aos componentes de matriz extracelular foram identificadas e, em sua maioria, são fatores de virulência. Phage display é considerada uma técnica poderosa na identificação de novos ligantes, inclusive de moléculas adesinas, importantes no primeiro estágio de infecção do hospedeiro. A técnica de shotgun phage display foi utilizada visando à obtenção de ligantes à células de mamíferos. Quatro bibliotecas, por inserção de fragmentos aleatórios obtidos por sonicação do DNA de L. interrogans nos fagomídeos pG8SAET (BBT1 e BBT2) e pG3DSS (BBT5 e BBT6), foram construídas. As bibliotecas BBT1 e BBT5 contém insertos maiores e as BBT2 e BBT6 contém insertos menores, com tamanhos médios de 1500 pb e 350 pb, respectivamente. Após ensaio de panning da BBT5 contra células de mamíferos e soro fetal bovino, as sequências de clones selecionados foram analisadas quanto a orientação correta e se a fusão estava em fase com a proteína pIII. As proteínas codificadas pelos genes LIC11719, LIC10769, LIC13143 e LIC12976 foram selecionadas com estas características. Os genes que codificam a LIC12976, LIC10768, LIC10769 e LIC13418, tiveram sua conservação avaliada em diferentes sorovares da espécie patogênica L. interrogans e no sorovar Patoc da espécie de vida livre L. biflexa. As proteínas LIC12976 (selecionada pela técnica de phage display) e LIC13418 (selecionada por ferramentas de bioinformática) tiveram suas sequências amplificadas por PCR, clonadas em pGEM T easy, subclonadas em vetor de expressão pAE e expressas na fração celular correspondente ao corpúsculo de inclusão em E. coli BL21 (DE3) Star pLysS e E. coli BL21 SI, respectivamente. Após renaturação e purificação destas proteínas por cromatografia de afinidade a metal bivalente, um grupo de cinco animais BALB/c fêmeas foi imunizado. Ambas as proteínas se mostraram imunogênicas com títulos dos soros policlonais 1:256000 e 1:512000, respectivamente. Em ensaio de Western Blot os soros foram específicos no reconhecimento das proteínas recombinantes e as proteínas nativas foram verificadas em extratos de sorovares patogênicos de L. interrogans. Em ensaios de adesão, as proteínas recombinantes aderiram às células A31, LLC-PK1 e Vero e especificamente à laminina. Em ensaios de interferência em células usando laminina houve um aumento da adesão das proteínas recombinantes, o que pode ser explicado pela ligação da laminina às células e uma maior ligação das LICs estudadas. Em ensaio de localização celular usando imunofluorescência e microscopia eletrônica, foi observado que ambas as proteínas se encontram na superfície da L. interrogans. No experimento de desafio animal, a LIC12976 e a LIC13418 não se mostraram protetoras. Este trabalho contribuiu para a identificação das novas adesinas LIC13418 e LIC12976 que podem participar da virulência de leptospiras patogênicas envolvendo a primeira etapa da infecção na interação patógeno-hospedeiro / In Leptospira interrogans, proteins capable to bind to extracellular matrix components have been identified and most of them are important virulence factors. Phage display is a powerful technique to identify new ligands, including adhesin molecules that are important in the first stage of host infection. A shotgun phage display technique was used in order to obtain cell ligands. Four libraries were constructed by inserting random fragments obtained by sonication of L. interrogans DNA into phagemids pG8SAET (BBT1 and BBT2) and pG3DSS (BBT5 and BBT6). The libraries BBT1 and BBT5 contain larger inserts and BBT2 and BBT6 contain smaller inserts, with 1500 bp and 350 bp average sizes, respectively. After panning of BBT5 against mammalian cells and bovine fetal serum, the sequences of selected clones were analyzed for correct orientation and fusion with pIII protein. The proteins encoded by genes LIC11719, LIC10769, LIC13143 and LIC12976 were selected. The genes LIC12976, LIC10768, LIC10769 and LIC13418 were evaluated for their conservation in different pathogenic serovars of L. interrogans and free-living L. biflexa serovar Patoc. Proteins LIC12976 (selected by phage display technique) and also LIC13418 that was selected by bioinformatic tools, were amplified by PCR, cloned into pGEM T easy, subcloned into expression vector pAE and expressed in cellular fraction corresponding to the inclusion body in E. coli BL21 (DE3) Star pLysS and E. coli BL21 SI, respectively. After protein renaturation protocol and purification by affinity chromatography, a group of five BALB/c mice was immunized with the purified proteins. Both proteins were shown to be immunogenic with 1:256000 and 1:512000 polyclonal sera titers, respectively. In Western blot the sera were specific to recognize recombinant proteins and native proteins were detected in pathogenic L. interrogans serovars extracts. In binding assays, recombinant proteins bind to A31, LLC-PK1 and Vero cells and specifically to laminin. In interference cell assay using laminin there was an increase of recombinant protein bindings, which can be explained by the laminin binding to cells and further binding of the recombinant LICs. In cellular localization assay using immunofluorescence and electron microscopy, it was observed that both are surface proteins of L. interrogans. In the animal challenge, the LIC12976 and LIC13418 were not protective. As a whole, this work contributed to the identification of LIC12976 and LIC13418 as new adhesins and they can participate in the virulence of pathogenic Leptospira in the first stage of host pathogen interaction.

Leptospirose é uma doença infecciosa emergente cujos agentes etiológicos são espécies patogênicas do gênero Leptospira. Leptospiras patogênicas possuem inúmeros genes específicos codificando proteínas com funções desconhecidas, sugerindo que as leptospiras apresentam fatores de virulência únicos. Adesinas bacterianas são importantes fatores de virulência e, assim, a identificação de adesinas conservadas em espécies patogênicas de Leptospira pela construção de bibliotecas genômicas expostas na superfície de bacteriófagos (shotgun phage display), seguida por seleção em células e/ou componentes da matriz extracelular (biopanning), pode revelar novos antígenos e alvos para o tratamento e prevenção da leptospirose. Bibliotecas foram construídas com o DNA genômico de L. interrogans fragmentado e o fagomídeo pG8SAET, sendo testadas algumas abordagens para clonagem como a ligação entre extremidades cegas (blunt-end) e técnicas baseadas em ligação entre extremidades coesivas, incluindo a obtenção de ORESTES e a utilização de adaptadores em grampo. Apesar de serem encontradas algumas limitações, a clonagem por ligação blunt-end se mostrou a mais eficiente para a construção de bibliotecas, sendo adotada para a construção de três bibliotecas em maior escala. A seleção de novas possíveis adesinas a partir das bibliotecas construídas foi realizada em células eucarióticas através da metodologia BRASIL. A primeira biblioteca (BBT1) exibiu 106 clones totais, a partir da qual foram selecionados quatro proteínas em fase apenas com a proteína VIII do fago (pVIII). No entanto, nenhuma delas seria exposta por programas de predição na bactéria. Outras duas bibliotecas foram construídas (BBT2 e BBT3), as quais obtiveram um número ideal de clones para uma ampla cobertura do genoma (>2x107 clones). Por apresentar maior proporção de clones válidos, a BBT2 foi utilizada para a seleção de adesinas, resultando em onze clones em fase com pVIII e/ou sequência sinal do fago. Análises por programas de predição revelaram três proteínas hipotéticas, denominadas LepA962, LepA069 e LepA388, as quais poderiam estar expostas ou ser secretadas pela bactéria, sugerindo uma possível função de adesina. O estudo da proteína LepA388 levou ao reconhecimento de outras doze proteínas semelhantes e pertencentes a uma família paráloga contendo um domínio denominado DUF_61, motivo de função desconhecida presente em proteínas compartilhadas somente entre as espécies patogênicas mais virulentas de Leptospira. Por esta razão, a proteína LepA388 foi a mais estudada. A clonagem de três porções da proteína (LepA388P, LepA388NR e LepA388F) para expressão heteróloga resultou em proteínas recombinantes insolúveis e, considerando a riqueza em resíduos de cisteína presente em sua estrutura, não foi possível renaturá-las adequadamente. Diante dos obstáculos encontrados, apenas a porção contendo a sequência apresentada pelo fago (LepA388P) foi utilizada para obtenção de antissoros em camundongos, os quais apresentaram altos títulos, demonstrando a alta imunogenicidade da proteína LepA388P. O reconhecimento de proteínas nativas da família paráloga DUF_61 em extratos de diferentes sorovares de Leptospira não foi observado, assim como sua expressão in vitro a partir de bactérias em diferentes condições de cultivo. Estudos adicionais sobre a expressão in vivo e funções dos membros desta família são necessários para uma compreensão mais ampla de seu papel na biologia de leptospiras e, possivelmente, na patogênese da leptospirose. / Leptospirosis is an emerging infectious disease whose etiologic agents are pathogenic species of the genus Leptospira. Pathogenic leptospires have countless specific genes encoding proteins with unknown functions, suggesting that leptospires have unique virulence factors. Bacterial adhesins are important virulence factors and so the identification of conserved adhesins in pathogenic Leptospira species from shotgun phage display libraries, followed by selection (biopanning) in cells and/or extracellular matrix components, can reveal new antigens and strategies for leptospirosis treatment and prevention. Libraries were constructed using fragmented genomic DNA from L. interrogans and pG8SAET phagemid vector. Cloning approaches included blunt-end ligation and techniques based in cohesive-end ligation, such as ORESTES strategy and hairpin linkers. Despite some limitations, cloning by blunt-end ligation was the most efficient for library construction, being adopted for the construction of three libraries on a larger scale. Selection of new possible adhesins was performed by biopanning of the libraries in eukaryotic cells through BRASIL methodology. The first library called BBT1 exhibited approximately 106 total clones, and its biopanning resulted in four proteins fused to phage protein VIII, but none of them were expected to be exposed by the bacteria. Other libraries were built (BBT2 and BBT3) which reached the expected number of clones to obtain a larger genome representation (> 2x107 clones). Since it showed the highest proportion of positive clones, BBT2 was selected to perform a second biopanning, resulting in eleven proteins fused to phage protein VIII and/or signal peptide. In silico analysis revealed three hypothetical proteins, named LepA962, LepA069 and LepA388, that would be exposed or secreted by the bacteria, suggesting a possible adhesin function. The study of LepA388 protein led to the recognition of twelve other similar proteins belonging to a paralogous family that contains a domain called DUF_61, domain of unknown function that is present in proteins shared only among the most virulent pathogenic species of Leptospira. For this reason, the LepA388 protein was the most studied. The cloning of three portions of the protein (LepA388P, LepA388NR and LepA388F) for heterologous expression resulted in insoluble recombinant proteins, and given the presence of many cysteine residues in its structure, it was not possible to renature them appropriately. In face of the imposed obstacles, only the portion containing the sequence presented by the bacteriophage (LepA388P) was used to obtain antisera in mice, which showed high titers, demonstrating the high immunogenicity of the protein LepA388P. Recognition of native DUF_61 paralogous family proteins in extracts from distinct Leptospira serovars was not observed, as well as its in vitro expression from bacteria cultured in different conditions. Additional studies on the in vivo expression and functions of members of this family are needed for a broader understanding of their role in leptospiral biology and possibly in the pathogenesis of leptospirosis.

This Masterâs thesis deals with evaluation of quality of Brno Combo combination rifle shotgun rifled barrelâs firing mechanism. It contains a proposal of criteria for evaluation of quality of firearm firing mechanisms. It further focuses on using measurement of primer deformation as a means of assessing the quality of a firing mechanism. Based on measurements made using a Focus Variation microscope, various geometrical parameters of fired and failed primers were analysed. The measurement results were processed using ANOVA and regression analysis. Based on output of these analyses, practical recommendations and further research proposals were formulated.

Highly directive loudspeakers have long been important tools for sound system designers, experimental acousticians, and many other professionals in the audio industry. They allow sound engineers to more easily manipulate the radiation pattern of their loudspeakers to accommodate the purpose of the venue. Many commercially available products, while exhibiting good directivity at mid and high frequencies, generally lack control in the low frequency range. A new method for controlling the radiation pattern of a loudspeaker at low frequencies has been developed and modeled extensively. Prototypes have been built and tested in an anechoic chamber. Results from computer modeling and experimental measurements will be presented and compared in this thesis.

No / Although the application of sequencing-by-synthesis techniques to DNA extracted from bones has revolutionized the study of ancient DNA, it has been plagued by large fractions of contaminating environmental DNA. The genetic analyses of hair shafts could be a solution: We present 10 previously unexamined Siberian mammoth (Mammuthus primigenius) mitochondrial genomes, sequenced with up to 48-fold coverage. The observed levels of damage-derived sequencing errors were lower than those observed in previously published frozen bone samples, even though one of the specimens was >50,000 14C years old and another had been stored for 200 years at room temperature. The method therefore sets the stage for molecular-genetic analysis of museum collections.