Orientador: Henrique Ferreira / Banca: Alessandra Alves de Souza / Banca: Patricia Pasquali Parise Maltempi / Resumo: Xanthomonas. citri subsp. citri (Xac) é o agente causal do cancro cítrico, uma das doenças mais graves que afetam plantas cítricas de importância comercial em todo o mundo. O controle eficaz para o cancro cítrico constitui na eliminação de plantas infectadas em programas rigorosos para conter a propagação da bactéria. No entanto, o relaxamento recente nas políticas para combater cancro cítrico em áreas como o estado de São Paulo - Brasil, está a contribuir para a propagação da doença. O conhecimento da biologia deste patógeno de plantas e também dos mecanismos envolvidos na interação planta-patógeno são de grande importância para apoiar o desenvolvimento de estratégias para lidar com o cancro cítrico. Um trabalho recente de nosso grupo demonstrou que os mutantes X. citri com disrupção do gene parB são comprometidos na segregação cromossômica e na capacidade de produzir os sintomas da doença na planta. No presente trabalho, nós estendemos nossas caracterizações, avaliando os efeitos da falta de parB em mutantes X. citri através de uma deleção limpa. ParB é uma proteína de ligação ao DNA e está envolvida no processo de segregação cromossômica através de interação com outras proteínas. Devido à dificuldade de deleção de genes envolvidos neste processo em X. citri, o nocaute de parB foi realizado numa variante abrigando um plasmídeo replicativo capaz de expressar cópias extras de ParB (ParB-TAP) sob o controle de para (promotor de arabinose). A viabilidade de X. citri parB nocaute (XacΔparB-pLAC2) foi avaliada em experimentos de curva de crescimento e em comparação com a estirpe do tipo selvagem, em condições de repressão ou de indução de parB-tap ligado a este promotor; O objetivo foi explorar as condições de depleção e superexpressão de ParB e seus efeitos através da caracterização do referido promotor. Em seguida, X. citri parB nocaute foi visualizado por microscopia de... / Abstract: Xanthomonas citri ssp. citri (Xac) is the causal agent of citrus canker, one of the most severe diseases that affect citrus plants of commercial importance around the world. An effective control for citrus canker constitutes the elimination of infected plants in rigorous programs to contain the spread of the bacteria. However, recent relaxation in the policies to combat citrus canker in areas such as the state of São Paulo, Brazil, the major orange juice producer in the world, are contributing to the spread of the disease. Therefore, knowledge of the biology of this plant pathogen and also of the mechanisms involved in plant-pathogen interaction are of great importance to support the development of strategies to deal with citrus canker. Recent work from our group demonstrated that X. citri mutants disrupted for parB are compromised in chromosome segregation and are unable to produce disease symptoms in plant. In the present work, we extended our characterizations by evaluating the effects of a lack of ParB in X. citri mutants carrying a clean deletion of its coding DNA. ParB is a DNA binding protein and is involved in chromosome segregation process through interaction with other proteins. Because of difficult in genes deletion involved this process in X. citri, the parB gene was deleted in a X. citri variant harboring a replicative plasmid able to express extra copies of ParB (ParB-TAP) under the control of the para (arabinose promoter). The viability of the X. citri parB knockout was assessed in growth curve experiments and compared with the wild type strain under different conditions of parB-tap repression or induction. The aim was to explore the conditions depletion and overexpression of ParB and its effects through the characterization of para in X. citri Thus, the X. citri parB knockout was visualized under differential interference contrast (DIC) microscopy in order to detect morphological alterations normally expected from ... / Mestre

Orientador: Ione Corrêa / Banca: Sílvia Maria Caldeira / Banca: Denise de Andrade / Resumo: Os estabelecimentos de saúde e as superfícies inanimadas que cercam o paciente guardam íntima relação com as infecções relacionadas a assistência e a saúde, sendo importantes focos de contato e de transmissão de agentes patogênicos e podem ser transferidos para as mais diversas superfícies através do contato direto e indireto. Existem inúmeras pesquisas que retratam que os artigos hospitalares podem se tornar veículos de disseminação, comprometendo a segurança do paciente. Diante desta problemática, este estudo objetivou-se em analisar as condições bacteriológicas de superficie de poltronas hematológicas para hemodiálise. Após aprovação do Comitê de Ética em pesquisa foi realizada a randomização das poltronas, duplo cego e iniciou a amostragem das quatro cadeira nos sete procedimentos em cinco locais diferentes na poltrona. O produto utilizado para higienização de rotina na unidade foi o álcool a 70% com compressa hospitalar composta de tecido 100% algodão em dimensão de 30 x 30 cm, umedecida com 40 ml de álcool 70%. Para amostragem bacteriológica utilizou-se campo estéril fenestrado para garantir coleta sempre no mesmo local utilizando Swab. O Swab foi transportado para o laboratório em meio de cultura gel Stuart para identificação. Após foi realizado teste de antibiograma das bactérias isoladas e teste de sensibilidade "in vitro" utilizando método de Kirby e Bauer com modificações conforme descrito por Corrêa (1988). Para o teste "in vitro" utilizou-se três desinfetantes frente as bactérias isoladas das poltronas que são consideradas de grande importância no controle de infecção hospitalar. O resultado demostrou que a maior unidade formadora de colônia foi em relação ao Staphilococcus sp, seguido de bacilus Gram positivo, Staphilococcus aureus, Pseudomonas, Enterobacter cloacae e Acinetobacter, com predominância do Staphilococcus sp em todas as ... / Abstract: Health facilities and inanimate surfaces surrounding the patient keep close relation with infections related to care and health, with important centers of contact and transmission of pathogens and can be transferred to many different surfaces through direct and indirect contact. There are numerous studies that show that the hospital items can become vehicles of dissemination, compromising patient safety. Faced with this problem, this study aimed to analyze the bacteriological conditions in the surface of hematologic arm for hemodialysis. After approval by the Research Ethics Committee of the randomization arm, double- blind trial was performed and started sampling the four chair the seven procedures in five different locations in the chair. The product used for routine cleaning of the unit was 70% alcohol with hospital pad composed of 100% cotton in size 30 x 30cm, moistened with 40 ml of 70% ethanol. Bacteriological sampling was used to ensure fenestrated sterile field in the same site collection using Swab. The swab was transported to the laboratory in culture medium gel Stuart for identification. After testing, was performed antibiogram of isolates and sensitivity test "in vitro" using Kirby and Bauer method with modifications as described by Cooke (1988). For "in vitro" test used three disinfectants front seats of the isolated bacteria that are considered of great importance in the control of hospital infection. The result demonstrated that the largest colony-forming unit was compared to Staphylococcus sp, followed by Gram-positive bacillus, Staphylococcus aureus, Pseudomonas, Enterobacter cloacae, and Acinetobacter, predominantly Staphylococcus sp on all surfaces of the chair, with predominance in the left arm armchair coinciding with the arm of the patient who has an arteriovenous fistula (70%). Regarding sensitivity, Acinetobacter were sensitive to all antibiotics tested, whereas Pseudomonas were sensitive to sulfa / trimethoprim, ... / Mestre

Orientador: Lucia Maria Carareto Alves / Banca: Lucia Helena Sipauba-Tavares / Banca: Rodrigo Matheus Pereira / Resumo: A aquicultura é uma atividade que está em contínuo crescimento, desta forma os ecossistemas aquáticos utilizados para tal atividade acabam sofrendo alterações nas condições da água e na comunidade microbiana do local. No presente trabalho, compararam-se as comunidades bacterianas presentes em águas de dois viveiros de piscicultura, um utilizado como reservatório de água (V1) e o outro com condições de elevada carga de nutrientes (V4), os quais estão inseridos em um sistema sequencial com fluxo contínuo de água (seis viveiros). A escolha dos viveiros V1 e V4, foi baseada em estudos anteriores no qual foi evidenciado um alto grau de eutrofização neste local. As coletas de água foram realizadas em dois períodos distintos um na seca (Julho e Agosto/2012) e outro na chuva (Janeiro e Fevereiro/2012). A comunidade bacteriana foi avaliada através do sequenciamento do gene 16S rRNA. A população bacteriana variou significativamente entre os dois viveiros e segundo a estação anual, seca ou chuva. No viveiro 1 observou-se uma grande proporção de Proteobacterias, em ambos os períodos, entretanto houve mudanças nas classes deste grupo, a maioria β-Proteobacterias (chuvas) e uma proporção equivalente de β e α-Proteobacterias (seca). No viveiro 4, foi observada uma alta frequência de Cyanobacterias principalmente na estação de seca, aproximadamente 80% da população bacteriana do local, enquanto no período de chuvas este grupo foi menor. A comparação da população bacteriana dos dois viveiros estudados em épocas distintas mostrou que as bactérias nestes locais variam de acordo com o período hidrológico e estão intimamente ligadas com a concentração de nutrientes do local. Estas diferenças são importantes na participação dos ciclos biogeoquímicos, principalmente envolvendo os ciclos do nitrogênio e fósforo e a sanidade do sistema aquático. / Abstract: The aquaculture is an activity that is continuous growing, in this way aquatic ecosystems used for such activity end up suffer changes in water conditions and microbial community local. In this study, we compared the bacterial communities present in waters of two fish farm ponds, a used as water reservoir (V1) and the other with conditions of high nutrient load (V4), which are inserted in a sequential system with continous water flow (six ponds). The choice of nurseries V1 and V4 was based on previous studies in which evidenced a high degree of eutrophication in this location. The water sampling were conducted in two distinct periods one in dry season (July and August/2012) and another in the rain (January and February/2012). The bacterial community was assessed by sequencing the 16S rRNA. The bacterial population varied significantly between the two ponds and according to season annual, dry or rain. In the pond 1 there was a large proportion of proteobacteria, in both periods, however there were changes in the classes of this group, most β-Proteobacteria (rain) and an equivalent proportion of β and α-proteobacteria (dry). In pond 4, we observed a high frequency of cyanobacteria mainly during the dry season, approximately 80% of the bacterial population of the place, while in the rainy season this group was lower. A comparison of the bacterial population of the two ponds studied at different times showed that the bacteria at these sites varies according to the period hydrological and are closely linked with nutrient concentration local. These differences are important in the participation in biogeochemical cycles, especially involving the cycles of nitrogen and phosphorus and health of the aquatic system. / Mestre

No description available.

Compositional data refers to simplex-valued data, or equivalently, nonnegative vectors whose totals are uninformative. This data modality is of relevance across several scientific domains. A classical example of compositional data is the chemical composition of geological samples, e.g., major-oxide concentrations. A more modern example arises from the microbial populations recorded using high-throughput genetic sequencing technologies, e.g., the gut microbiome. This dissertation presents a set of methodological and theoretical contributions that advance the state of the art in the analysis of compositional data. Our work can be divided along two categories: problems in which compositional data represents the input to a predictive model, and problems in which it represents the output of the model. For the first class of problems, we build on the popular log-ratio framework to develop an efficient learning algorithm for high-dimensional compositional data. Our algorithm runs orders of magnitude faster than competing alternatives, without sacrificing model quality. For the second class of problems, we define a novel exponential family of probability distributions supported on the simplex. This distribution enjoys attractive mathematical properties and provides a performant probability model for simplex-valued outcomes. Taken together, our results constitute a broad contribution to the toolkit of researchers and practitioners studying compositional data.

A recently isolated freshwater methanogenium species, Methanogenium wolfei, is characterized. Cells were irregular cocci, measuring 1.5 to 2.0 micrometers in diameter. No motility was observed, but 1 to 2 flagella per cell were observed after staining with Gray's Flagella Stain. Colonies formed by this species were small, shiny, and green-brown in color. Formate or hydrogen plus carbon dioxide served as substrates for growth. The optimal temperature for growth was found to be 45 degrees centigrade with minimal growth below 30 degrees centigrade and above 55 degrees centigrade. The optimal pH for growth was determined to be 6.8. Optimal growth was obtained within a 0.0 to 0.2M range of added sodium chloride. Acetate and arginine were required for growth. DNA base composition was 61.1 mol%. G+C. The presence of coenzyme F-420 at a concentration of 134 mg/kg cells (wet weight) was determined in cell extracts. The enzyme NADP reductase was found to be present and was partially characterized.

Bacterial strains resistant to arsenite, arsenate (or both) are readily isolated from nature. The resistance, in many cases, can be shown to be determined by conjugal plasmids. The mechanisms by which these plasmids confer resistance to arsenic compounds are entirely unknown. This study was undertaken to shed light on some of the physiological and genetic aspects of this resistance using plasmid-bearing strains of Escherichia coli which are highly resistant to both arsenite and arsenate. Most studies were carried out using E. coli J53 (R773) or the plasmid-free strain J53.

This study is a continuation of the investigations of Hall (1976), Storey (1977), and Berkowitz (1978) on antimicrobial susceptibility patterns of bacteria isolated from local hospitals in Stockton, California. It extends the work of Hall (1976) on the K-E-S group to include three species of Proteus and Escherichia coli. New antibiotics (tobramycin, amikacin and cefamandole) are also added to the antibiogram.

No description available.

No description available.