Made available in DSpace on 2015-07-22T20:50:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Mycobacterium avium e Mycobacterium kansasii são micobactérias não tuberculosas frequentemente isoladas em infecções em pacientes HIV positivos. Em um projeto anterior do laboratório foi estudado um cultivo misto de M. avium e M. kansasii isolado da medula óssea de um paciente HIV positivo. Estudando colônias isoladas deste cultivo, foi possível observar que a cepa de M. kansasii possuía a sequência de inserção IS1245, que é especifica de M. avium. A presença deste elemento de inserção em M. kansasii foi confirmada por PCR-IS1245, RFLP-IS1245 e sequenciamento. Este estudo teve como objetivo investigar o mecanismo de transferência da IS1245 para M. kansasii. Uma banda de aproximadamente 100 kb foi detectada por PFGE em colônias de M. avium e de M. kansasii deste cultivo misto. Testes de mobilidade desta banda de DNA em géis de PFGE, em diferentes condições de corrida, e testes com exonucleases e com topoisomerase I comprovaram que esta banda era um plasmídeo linear (pMA100), que continha proteínas covalentemente ligada nos seus terminais 5’. Estes achados levaram à hipótese de que o plasmídeo pMA100 seria responsável pela transferência natural do elemento IS1245 de M. avium para M. kansasii por conjugação. Experimentos in vitro reproduziram o evento de conjugação, tanto com a cepa de M. kansasii isolada do cultivo misto, como com outras duas cepas de M. kansasii não relacionadas. A sequência de inserção se manteve estável no genoma de M. kansasii após 10 subcultivos e foi observada a ocorrência de transposição de modo replicativo em M. kansasii. Pela primeira vez está sendo demonstrada a transferência horizontal de genes natural entre espécies diferentes de micobactérias. / Mycobacterium avium and Mycobacterium kansasii are non-tuberculous mycobacteria frequently isolated in infections from HIV positive patients. In a previous study from our laboratory, a mixed culture of M. avium and M. kansasii from a bone marrow isolate of an HIV positive patient was studied. The analysis of isolated colonies allowed the detection of the insertion sequence IS1245, specific from M. avium, in M. kansasii. The presence of this element in M. kansasii was confirmed by PCR-IS1245, RFLP-IS1245 and sequencing. The objective of this study was to investigate the mechanism of transference of the IS1245 to M. kansasii. A band of approximately 100 kb was detected by PFGE in colonies of M. avium and M. kansasii from this mixed culture. Tests of mobility of this DNA band in PFGE gels, in different running conditions, and tests with exonucleases and topoisomerase I demonstrated that this band was a linear plasmid (pMA100) with proteins covalently linked to the 5’ ends. These findings led to the hypothesis that the pMA100 plasmid was responsible for the natural transference of the IS1245 element from M. avium to M. kansasii by conjugation. Experiments performed in vitro reproduced the conjugation event, not only with the M. kansasii strain from the mixed culture, but also with other two unrelated M. kansasii strains. The insertion sequence was stably maintained in the M. kansasii genome after 10 subcultures and its replicative transposition in M. kansasii was also observed. For the first time the natural horizontal gene transfer between different species of mycobacteria has been demonstrated. / TEDE / BV UNIFESP: Teses e dissertações

Memoria para optar al titulo profesional de: Ingeniera Agrónoma / Las cerezas frescas actualmente enfrentan un mercado altamente competitivo. Entre los mayores productores de cerezas dulces se encuentran Estados Unidos, Turquía e Irán. Chile es el tercer exportador a nivel mundial y el primero del Hemisferio Sur. Tal relevancia a nivel mundial hace necesario evaluar la competitividad que el país tiene en el negocio. El objetivo principal de este estudio fue analizar la competitividad de las cerezas frescas chilenas de exportación en el mercado internacional y como objetivos específicos el análisis de los factores determinantes de la competitividad, caracterizar las brechas logísticas del transporte de exportación, proponer orientaciones para contrarrestar las amenazas del negocio de cerezas frescas. Se realizaron entrevistas a informantes calificados, los cuales entregaron sus apreciaciones respecto a la competitividad de las cerezas frescas chilenas de exportación. Esta información fue fundamental para llevar a cabo el modelo de cinco fuerzas de Porter para este producto. El análisis se acompañó también de indicadores de competitividad, como la balanza comercial relativa, transabilidad, grado de apertura exportadora, grado de penetración de las importaciones e indicador de especialización. Todos los datos fueron extraídos del período comprendido entre los años 2006-2011. Finalmente con estos indicadores se elaboró un ranking para determinar los países más competitivos. Chile, resultó ser bastante competitivo en el negocio de cerezas frescas de exportación. Además, posee un consumo interno marginal, coincidiendo con la condición de exportador neto y abastecedor propio. Así mismo presenta ventajas de producción primaria y arancelaria que le permiten posicionarse como un actor importante a nivel mundial. / At present, fresh cherries face a very competitive market. The largest producers are The United States, Turkey and Iran. Chile is the third exporter in the world and first in the South Hemisphere. Such world level relevance makes it necessary to evaluate the country’s competitiveness in the market. The main objective of this project was to analyze the competitiveness of Chilean export fresh cherries in the international market and the specific objectives : analysis of the determinants of competitiveness gaps characterize export transport logistics, propose guidelines to counter threats of fresh cherries business Qualified specialists were interviewed to obtain important tips respecting the competitiveness of fresh cherries export. This information was very important to elaborate Porter's five forces model regarding Chilean cherries. The analysis was also accompanied with indicators of competitiveness, like the relative trade balance, tradability, exporting openness rate, degree of import penetration and indicator of specialization. All the data were collected in the period between 2006 and 2011. Finally with this information a ranking to determine the competitiveness of cherry exporting countries was built. Chile turned out to be one of the best evaluated countries, having a low internal consumption, one of the main characteristics of the net exporter and self sufficient country. Besides, it shows important advantages in primary production and low departure taxes allowing for its placing among one of the most important actors of the market.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2015-11-16T16:31:34Z No. of bitstreams: 1 texto completo.pdf: 1375656 bytes, checksum: 6b33bdf6230c90a2e18e46517b201f11 (MD5) / Made available in DSpace on 2015-11-16T16:31:34Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1375656 bytes, checksum: 6b33bdf6230c90a2e18e46517b201f11 (MD5) Previous issue date: 2015-06-03 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Minas Gerais é o principal produtor de leite de cabra na região Sudeste e o terceiro principal estado do país nessa atividade. A paratuberculose é uma enfermidade intestinal crônica, causada por Mycobacterium avium subsp. paratuberculosis (Map), que acomete principalmente ruminantes e é transmitida pela ingestão de alimentos ou água contaminados por fezes de animais acometidos. O objetivo do trabalho foi identificar e caracterizar Mycobacterium avium subsp. paratuberculosis em fazendas de caprinos leiteiros da Zona da Mata de Minas Gerais. Foram estudadas dez propriedades, caracterizadas através da aplicação de um questionário com a pessoa responsável pelo manejo. Foram coletadas amostras de fezes e de leite dos 467 animais amostrados, que foram inoculadas em meio HEYM. As amostras de leite e as colônias suspeitas foram submetidas à PCR e aquelas consideradas positivas foram sequenciadas. Onze (2,36%) animais foram considerados positivos para a presença de Map, em quatro (40%) propriedades. Através das técnicas utilizadas, concluiu-se que Map está presente nas propriedades de caprinos leiteiros da Zona da Mata de Minas Gerais. Com esse estudo, foi possível analisar e caracterizar os diferentes modos de produção de leite de cabra empregados na Zona da Mata. Os produtores têm relativa instrução, mas ainda convivem com a baixa produtividade e o baixo rendimento da produção, o que leva a maioria a necessitar de outras fontes de renda. O incentivo governamental exerce papel fundamental na mudança do cenário atual da caprinocultura leiteira dessa mesorregião e, levando à estruturação da cadeia produtiva, alcança melhores resultados de produção e geração de emprego e renda no meio rural. / The participation of dairy goat in the Brazilian agricultural scenario has increased and has consolidated as profitable. Minas Gerais is the main producer of goat's milk in the Southeast and the third largest state in the country in this activity. The paratuberculosis is a chronic intestinal illness caused by Mycobacterium avium subsp. paratuberculosis (Map), which mainly affects ruminants and is transmitted by ingesting food or water contaminated by feces of affected animals. The objective was to identify and characterize Mycobacterium avium subsp. paratuberculosis in dairy goat farms in the Zona da Mata of Minas Gerais. Ten properties were studied, characterized by applying a questionnaire to the person responsible for the handling. Samples of feces and milk were collected of 467 animals studied, and inoculated in HEYM medium. Samples of milk and suspected colonies were submitted to PCR, and the samples considered positive were sequenced. Eleven (2.36%) animals were considered positive for the presence of Map, in four (40%) properties. Through the techniques used, it was concluded that Map is present in dairy goats properties of Zona da Mata of Minas Gerais. With this study, we analyzed and characterized different types of goat production used in the Zona da Mata. Producers have relative education, but still living with low productivity and low income of their production, which leads most in need of other sources of income. The government incentive plays a fundamental role in changing the current scenario of dairy goat at this region and, leading to the structuring of the production chain, achieves better results of production and generation of employment and income in rural areas.

Mycobacterium avium, an opportunistic human pathogen, infects between 25 and 50% of advanced-stage acquired immuno-deficiency syndrome (AIDS) patients in the United States. M. avium has been isolated from many environmental sources including: natural waters, soils, and aerosols. M. avium has also been recovered from within municipal and hospital drinking water systems. Rhesus macaques (Macaca mulatta) infected with the simian HIV analog, SIV, have been shown to acquire M. avium infections from potable water. Reduced-aggregate fractions (cell suspensions free of large aggregates) of Mycobacterium avium were exposed to chlorine, monochloramine, chlorine dioxide, and ozone and kinetics of disinfection measured. Chlorine disinfection kinetics was also measured in M. avium cultures grown in biofilms. M. avium exhibited a high resistance to chlorine compared to E. coli. M. avium CT99.9% (disinfectant concentration x time to 3 logs cell inactivation) values were between 571- and 2318 -times those of E. coli. Clinical isolates of M. avium showed 0.24 and 2.5-fold increase in resistance to chlorine compared to their pulsed-field-gel-electrophoresis- (PFGE) matched environmental isolates. M. avium strains exhibited a mixed response to exposure to monochloramine. The CT99.9% values of three strains (2 clinical, 1 environmental) were between 6.3- and 23.5- times that of E. coli. Two strains (1 clinical, 1 environmental) exhibited CT99.9% values approximately the same as E. coli, a difference from all the other disinfectants which were much less effective on M. avium than on E. coli. M. avium strains exhibited a high resistance to chlorine dioxide when compared to E.coli. M. avium CT99.9% values of between 133- and 706- times higher that that of E. coli. In the paired isolates tested, the clinical isolate was 5.3 times more resistant than the matched environmental isolate. M. avium exhibited a high resistance to ozone when compared to E. coli. M. avium strains exhibited a CT99.9% value of between 52 and 90 times higher that that of E. coli. In the paired isolates tested, the clinical isolate was nearly identical as judged by CT99.9% values. M. avium strain 5002 exhibited an unusual disinfection kinetics curve. Disinfection rate increased by a non-logarithmic factor, indicating that inactivation efficiency was increasing over time. M. avium strain 1060 showed between a 17% decrease to a 265% increase in CT99.9% value when grown as biofilms as opposed to suspension. Due to the large variance in biofilm density and and CT99.9% values, any conclusions based on these experiments should be considered tentative at best. M. avium's resistance to chlorine and chlorine dioxide approaches that of the protozoan cysts of Giardia muris and Entamoeba hystolytica. M. avium is much less resistant, relatively, to monochloramine possessing values similar to E. coli. Ozone resistance of M. avium is two orders of magnitude greater than E. coli and one order of magnitude of less than G. muris cysts. A critical concentration threshold level for chlorine dioxide was found. That is, there was no linear relationship between concentration of chlorine dioxide and cell inactivation. Initial experiments using a range of concentrations from 0.1 ppm to 0.5 ppm chlorine dioxide showed a biphasic curve with the inflection point (indicating the critical concentration) between 0.3 and 0.4 ppm chlorine dioxide. / Master of Science

No description available.

<p> This thesis describes the isolation and structural determination of flavonoids from the heart wood of Prunus avium as well as synthesis of polyhydroxy pyrrolidine derivatives and aniline core structures as potential antibacterial agents. Nitrogen-synthons containing saturated heterocyclic systems and aniline core structures are important synthons in organic chemistry because of their presence in many biologically-active natural products. Mycobacterial viability is dependent upon the ability of the organism to produce an intact cell wall. Therefore, compounds that interfere with the biosynthesis of the cell wall complex glycons have the potential to become new drugs for the treatment of mycobacterial infections. The oligosaccharide galactan is one of the major structural components of the outer wall of the micro-organism. Galactofuranose is essential for cell growth and survival and therefore, its biosynthesis constitutes a new drug target. The biosynthetic process involves several enzymes having Uridine-diphosphogalacto furanose (UDP-Galf) as the substrate; uridine 5^1 -diphosphogalacto pyranose mutase which catalyzes the interconversion of UDP galacatopyranose to UDP-galactofuranose as well as Galf-transferase. We are seeking and designing molecules that could be mechanistic probes and/or inhibitors of efflux pumps to potentially combat multidrug resistance.</p> <p> The isolation and structure-determination of six naturally occurring Flavan-type Natural products was performed. Such derivatives are known to reverse multiple-drug-resistance (MDR) in persistent microbial infections. The synthesis of pyrrolidine-based antibacterial agents was attempted using two different approaches from tartaric acid. These derivatives were designed as potential transition-state mimics of a carbohydrate processing enzyme specific to TB. A synthetic approach to the aromatic core structure of the antibacterial agent Platensimycin was also investigated. The synergistic use of cytotoxic agents in conjunction with efflux-pump modulators is an emerging area of research in the MDR field; our efforts to make available materials for high-throughput screening in this area will be described.</p> / Thesis / Master of Science (MSc)

Consumer exposure to opportunistic pathogens in potable water systems poses a significant challenge to public health as manifested by numerous cases of pneumonia, non-tuberculosis lung disease, and keratitis eye infections. Water utilities have extensive understanding in control of heterotrophic and coliform bacteria re-growth in water distribution systems via disinfection, control of assimilable organic carbon (AOC), and biologically degradable organic carbon (BDOC). However, much little is known about the effect of AOC on the proliferation of heterotrophic bacteria and pathogens within premise plumbing. This thesis is the first systematic examination of opportunistic pathogen persistence and amplification in simulated glass water heaters (SGWH) as a function of influent organic matter concentration. The role of plumbing conditions that may internally generate AOC is critically examined as part of this evaluation. Strong correlations were often observed between influent organic matter and heterotrophic bacteria in effluent of SGWH as indicated by 16S rRNA gene abundance (average R2 value of 0.889 and 0.971 for heterotrophic organisms and 16S rRNA respectively). The correlation was strongest if water turnover was more frequent (every 48-72 hours) and decreased markedly when water changes were less frequent (stagnation up to 7 days). No simple correlations were identified between the concentration of pathogenic bacteria (L. pneumophila, M. avium, A. polyphaga, and H. vermiformis) and AOC, although correlations were observed between M. avium and TOC over a limited range (and only for a subset of experiments). Indeed, there was little evidence that Legionella and Acanthamoeba proliferated under any of the conditions tested in this work. Parallel experiments were conducted to examine the extent to which factors present in premise plumbing (e.g. sacrificial magnesium anode rods, cross-linked polyethylene, nitrifying bacteria, and iron) could influence water chemistry and influence growth of bacteria or specified pathogens. Although these factors could strongly influence pH, dissolved oxygen concentrations, and levels of organic matter (e.g. iron, magnesium, nitrifying), there was no major impact on effluent concentrations of either heterotrophic bacteria or premise plumbing pathogens under the conditions investigated. While additional research is needed to confirm these findings, at present, there is no evidence of correlations between organic matter and pathogen concentrations from SGWH under conditions tested. Substantial effort was also invested in attempting to identify SGWH and oligotrophic nutrient conditions that would consistently support L. pneumophila and A. polyphaga amplification. A review of the literature indicates no prior examples of large scale amplification of these microorganisms at nutrient levels commonly found in synthesized potable water. It is likely that a complex combination of abiotic and biotic factors (i.e. micronutrients, necrotrophic growth, ambient water temperature, disinfectant type and dose, plumbing materials, water usage patterns), which are not yet fully understood, control the amplification and viability of these pathogenic organisms in premise plumbing systems. / Master of Science

Proteins of the cytoplasmic membrane of Mycobacterium avium were investigated to identify those which were: (1)intrinsic or extrinsic, (2) attached to the cell wall, (3)surface accessible and (4) excreted. In addition sera containing anti-cytoplasmic membrane proteins were obtained and preliminary purification of the cytoplasmic membrane protein was attempted. The predominating cytoplasmic membrane protein of 31,000 daltons (MCMP) was found to be intrinsic, attached to the cell wall and possibly surface accessible. The MCMP was not excreted, even in media in which the MCMP is not found in the cytoplasmic membrane. Other cytoplasmic membrane proteins were also found to be intrinsic; a few were likely to be extrinsic based upon their separation from the membrane in sucrose gradients. Cytoplasmic membrane proteins of 66, 000, 115, 000 and 129 dalton were surface accessible as judged by I 125-Iodobead labeling. Antisera against the HCMP and other cytoplasmic membrane proteins was obtained and will be useful in further cytoplasmic membrane protein characterization. Acetone precipitation of a cytoplasmic membrane preparation was performed to partially purify the MCMP. The data from this study can be used for the development of serodiagnostic reagents for detecting mycobacterial infection. / Master of Science

Mycobacterium avium is human and animal opportunistic pathogen responsible for disseminated disease in immunocompromised patients. Mycobacteria have a capacity to adapt to the environmental conditions by inducing enzyme activities and altering their metabolism. M. avium A5 cells were grown in a defined minimal medium (Nitrogen Test Medium) with glutamine, nitrite, nitrate, or ammonia as sole nitrogen source at a concentration of 2 mM at 370C aerobically. The strain grew well on all the nitrogen sources except nitrite. It grew slowly on nitrite with a generation time of 6 days and cultures were not viable after 4 weeks of storage. These data confirm that M. avium can utilize a single nitrogen source in a defined minimal medium as documented by McCarthy (1987). M. avium genome has been sequenced and contains genes sharing sequence similarities to respiratory nitrate reductase and dissimilatory nitrite reductases. Because, M. avium can use nitrate or nitrite as sole nitrogen source for growth (McCarthy, 1987), it must have assimilatory nitrate- and nitrite-reductases. Nitrate- and nitrite-reductase activities of M. avium cells growing aerobically or undergoing anaerobic shift in the presence of ammonia, nitrate or ammonia and nitrate in combination were measured. M. avium produced nitrate- as well as nitrite-reductase activity. Nitrite- and nitrate-reductases used either NADH or NADPH as an electron donor. Nitrite reductase activity was greater than nitrate reductase activity. This observation supports the rapid reduction of nitrite and slow reduction of nitrate in M. avium as documented by McCarthy (1987) and explained why M. avium gives a negative result by the standard nitrate reductase test. In addition to assimilatory enzyme activity, M. avium A5 also produced dissimilatory nitrate- and nitrite-reductase activities. / Master of Science

Organisms of the <i>Mycobacterium avium</i> complex cause disseminated infections in 25 to 50 % of patients with AIDS. To assess the likelihood of exposure to M avium, we attempted to recover M. avium complex from environmental samples in geographical areas (Boston, Massachusetts; Hanover, New Hampshire; Helsinki, Finland; Nairobi, Kenya; and Kinsasha, Zaire) located near <i>M. avium</i> infected AIDS patients. Although <i>M. avium</i> was recovered from environmental samples at all sites, it was found more frequently in water supply systems in the United States and Finland (8/25, 32 %) compared to water supply samples from Africa (0/14, 0%). To determine if <i>M. avium</i> isolates recovered from the same geographical area as AIDS patients shared phenotypic and genetic characteristics with clinical AIDS <i>M. avium</i> isolates (recovered by collaborating laboratories), the ability to grow at 43°C, cadmium-and streptomycin-resistance, and the presence of plasmids were used as epidemiological markers. We found that environmental isolates in this study shared similar characteristics with the clinical AIDS <i>M. avium</i> isolates. Compared to developed countries, the prevalence of <i>M. avium</i> infections among AIDS patients in developing countries (i.e., Africa) is very low. To determine if <i>M. avium</i> was absent in the African environment, we attempted to recover the organisms from water and soil in Kampala, Uganda. <i>M. avium</i> was recovered from 43 % of environmental samples, and these isolates shared similar phenotypic and genetic characteristics with <i>M. avium</i> isolates from the United States. Cigararette smoking was identified as a possible risk factor for HIV infected individuals. M avium isolates were recovered from several brands of cigarettes, suggesting that cigarettes are a possible source of infection. / Master of Science