Foram avaliados 25 reservatórios de água dos equipos odontológicos da Clínica de Dentística/Endodontia da FOB/USP com relação à presença de micro-organismos e a ação do ultrassom (US) na remoção do biofilme. Amostras de 10ml de água foram obtidas e alíquotas de 25l in natura e diluída até 10-4 foram semeadas pela técnica da gota nos meios: R2A Agar (R2A), Plate Count Agar (PCA), Peptona Diluída (PD) e Sabouraud Dextrose Agar com cloranfenicol a 1% (SDA), incubadas a 24º C por 72 horas. A água dos reservatórios foi descartada e 500 ml de água destilada esterilizada foi adicionada, sendo submetidos à ação do ultrassom (US) por 15 minutos, seguidos do mesmo procedimento descrito anteriormente. As colônias de bactérias foram quantificadas e os fungos foram identificados por micro-cultivo. A média da detecção de UFC/ml antes e após o US foi de 173.787 e 15.841 para o R2A, 104.873 e 3.034 para o PCA e de 245.824 e 8.231 para o PD. A média de fungos foi de 52,4 antes e 19,2 UFC/ml após ação do US. Fungos foram detectados em 20 reservatórios antes e em 12 deles após uso do US. O Penicillium sp apresentou prevalência de 36% nos reservatórios de água avaliados. Os resultados obtidos permitem concluir que o US foi eficiente em desestruturar o biofilme, embora não o elimine por completo, apresentando maior efetividade na desestruturação de bactérias. / A total of 25 waterline unit reservoirs of the odontological sets from the Dentistry/Endodontic Clinic of FOB/USP were assessed, in relation to the presence of microorganisms and the ultrasound action (US) on the biofilm removal. Waterline samples of 10ml were obtained from aliquots of 25l in natura and diluted until 10-4, then, they were spread using the dripping technique on the means: R2A Agar (R2A), Plate Count Agar (PCA), diluted Peptone (DP) and Sabouraud Dextrose Agar with cloranfenicol at 1% (SDA), being incubated at 24º C for 72 hours. The waterline units of the reservoirs were discarded and 500 ml of sterilized distilled water was added, submitted to ultrasound action (US) for 15 minutes, following the same procedure described afore. The bacteria colonies were quantified and the fungi were identified through micro-culture. The average of detection of UFC/ml before and after US was 173.787 and 15.841 for R2A, 104.873 and 3.034 for PCA and of 245.824 and 8.231 for PD. The fungi average was 52,4 before and 19,2 UFC/ml after the action of US. Fungi were detected in 20 reservoirs before and 12 after using US. Penicillium sp showed a prevalence of 36% in the waterline reservoirs assessed. The results obtained, led to the conclusion that US was efficient to break the structure of the biofilm, although it did not eliminate it completely, showing more effectiveness to break the bacteria structure.

Foram avaliados 25 reservatórios de água dos equipos odontológicos da Clínica de Dentística/Endodontia da FOB/USP com relação à presença de micro-organismos e a ação do ultrassom (US) na remoção do biofilme. Amostras de 10ml de água foram obtidas e alíquotas de 25l in natura e diluída até 10-4 foram semeadas pela técnica da gota nos meios: R2A Agar (R2A), Plate Count Agar (PCA), Peptona Diluída (PD) e Sabouraud Dextrose Agar com cloranfenicol a 1% (SDA), incubadas a 24º C por 72 horas. A água dos reservatórios foi descartada e 500 ml de água destilada esterilizada foi adicionada, sendo submetidos à ação do ultrassom (US) por 15 minutos, seguidos do mesmo procedimento descrito anteriormente. As colônias de bactérias foram quantificadas e os fungos foram identificados por micro-cultivo. A média da detecção de UFC/ml antes e após o US foi de 173.787 e 15.841 para o R2A, 104.873 e 3.034 para o PCA e de 245.824 e 8.231 para o PD. A média de fungos foi de 52,4 antes e 19,2 UFC/ml após ação do US. Fungos foram detectados em 20 reservatórios antes e em 12 deles após uso do US. O Penicillium sp apresentou prevalência de 36% nos reservatórios de água avaliados. Os resultados obtidos permitem concluir que o US foi eficiente em desestruturar o biofilme, embora não o elimine por completo, apresentando maior efetividade na desestruturação de bactérias. / A total of 25 waterline unit reservoirs of the odontological sets from the Dentistry/Endodontic Clinic of FOB/USP were assessed, in relation to the presence of microorganisms and the ultrasound action (US) on the biofilm removal. Waterline samples of 10ml were obtained from aliquots of 25l in natura and diluted until 10-4, then, they were spread using the dripping technique on the means: R2A Agar (R2A), Plate Count Agar (PCA), diluted Peptone (DP) and Sabouraud Dextrose Agar with cloranfenicol at 1% (SDA), being incubated at 24º C for 72 hours. The waterline units of the reservoirs were discarded and 500 ml of sterilized distilled water was added, submitted to ultrasound action (US) for 15 minutes, following the same procedure described afore. The bacteria colonies were quantified and the fungi were identified through micro-culture. The average of detection of UFC/ml before and after US was 173.787 and 15.841 for R2A, 104.873 and 3.034 for PCA and of 245.824 and 8.231 for PD. The fungi average was 52,4 before and 19,2 UFC/ml after the action of US. Fungi were detected in 20 reservoirs before and 12 after using US. Penicillium sp showed a prevalence of 36% in the waterline reservoirs assessed. The results obtained, led to the conclusion that US was efficient to break the structure of the biofilm, although it did not eliminate it completely, showing more effectiveness to break the bacteria structure.

This research deals with the changes in cellular morphology of Azotobacter vinelandii cultured on nutrient agar. In particular, this study is concerned with the formation of intracellular particles and a description of their size and sequence of appearance. Changes in morphology of Azotobacter vinelandii grown on nutrient agar are contrasted photographically with morphology of Azotobacter vinelandii grown on Burk's nitrogen free medium.

No description available.

Background: Bacteriophage Φ6 is a lipid-enveloped dsRNA bacteriophage. The limitations in our knowledge of how this bacteriophage occurs in the environment are limited by non-selective isolation techniques. Research on finding phages in the environment in the past has employed the Double Agar Layer (DAL) plaque assay using Tryptic Soy Agar (TSA), a non-selective media. The bacterial host for bacteriophage Φ6 is Pseudomonas syringae. In this study, we tested Pseudomonas Agar, a selective media that suppresses the growth of bacteria except Pseudomonas species, in the standard double agar layer plaque assay for Φ6. Methods: DAL plaque assays were performed to determine the sensitivity of both Tryptic Soy Agar (TSA) and Pseudomonas Agar (PA) for determining the titer of pure bacteriophage Φ6 stocks. We used Pseudomonas syringae (HB10Y) as the host, and the plaque formation on both agars was compared. Following the evaluation of PA with pure Φ6 stocks, PA effectiveness for Φ6 isolation from environmental samples was tested in spiked waters obtained from irrigation ponds at an agricultural farm. Results: Comparison of TSA and PA using pure Φ6 cultured in the laboratory and spiked environmental samples showed that PA agar can detect bacteriophage Φ6 as well as the standard DAL assay using TSA. On PA, formation of clear visible plaques comparable to the plaques formed using TSA was observed. Conclusions: Pseudomonas Agar can be used for the isolation of bacteriophage Φ6 in environmental samples. This may enhance the detection of these phages in the environment.

Mon projet de thèse a été réalisé en partenariat avec l'entreprise BioMérieux, qui produit des milieux de culture à base de gel d'agar coulés dans des boîtes de Pétri à destination du secteur biomédical. Ces gels, remplis d'eau à 95 %, sont susceptibles d'en relâcher par évaporation ou sous l'effet d'une perturbation externe. Le gel se contracte et peut se détacher des parois de la boite lors de la production ou lors de leur incubation. Ma thèse a consisté à identifier les paramètres clefs qui influent sur la contraction de ces milieux de culture aussi bien au niveau de la composition du gel que des propriétés de surface des parois de la boîte de Pétri. Ce travail expérimental m'a permis d'associer un panel de techniques originales comme la rhéologie à force normale contrôlée, une centrifugeuse, l'interférométrie ou encore la méthode flot optique. J'ai ainsi mis à jour les moteurs du détachement du gel des parois des boîtes et identifier des solutions concrètes pour y remédier / My PhD work was carried out in partnership with the company BioMérieux, a leader int he production of agar-based culture media, cast in Petri disches and used in microbioly. Being mainly composed of water (>95 % wt.), agar gels are naturally prone to solvent-loss by evaporation either at rest or under an external perturbation. As a result, the gel shrinks and detaches from the sidewall fo dish. The goal of my PhD work was to identify the key paramters driving the gel detachment, in relation with both the gel chemical composition, as well as the dish surface properties. This expzrimental word has allowed me to use a wide array of thecniques such as normal force controlled rheology, intererometric observations, or optical flow analysis applied to the gel deformation. I succesfully unravelled the driving forces that lead to the gel detachment from the sidewall of the dish and proposed concrete solutions to be implemented on a commercial scale to prevent il.

Se analizaron 60 muestras de Salchicha tipo Huacho de los Mercados de Abastos del Cercado de Lima, con la finalidad de determinar la incidencia de Listeria monocytogenes. Estas muestras se llevaron al Laboratorio de Microbiología de la Facultad de Farmacia y Bioquímica de la Universidad Nacional Mayor de San Marcos, en recipientes estériles, refrigerados y se procesaron dentro de las 24 horas de colectadas. Para el análisis microbiológico se utilizó la técnica según USDA- FSIS, que consta de tres fases: Pre-enriquecimiento, Enriquecimiento de la muestra y siembra en agares selectivos, pruebas Bioquímicas, Catalasa, Gram positivos y la prueba del CAMP para su confirmación. La incidencia de L. monocytogenes en Salchicha tipo Huacho, en los Mercados de Abastos del Cercado de Lima es de 78%, siendo un valor considerable y que supera a los valores reportados en estudios a nivel internacional. Estos resultados permiten considerar que la Salchicha tipo Huacho se constituye como un alimento de riesgo potencial para la Salud Pública. / --- 60 samples of the Huacho Sausage from the Food Markets in Cercado de Lima, in Lima, Peru, were analyzed in order to determine the incidence of Listeria monocytogenes. These samples were taken to the Laboratory of Microbiology to the Faculty of Pharmacy and Biochemistry at the National University of San Marcos. They were taken in sterile containers for being refrigerated. Then they were processed within 24 hours of being collected. The USDA-FSIS technique was used for microbiological analysis, which consists of three phases: Pre-enrichment of the sample, Sample Enrichment and Reseeding on selective agars. At the same time, some biochemical tests were applied, such as the positive Catalase test, the test of Great Positive, and CAMP test to confirm the results. The incidence of the Listeria monocytogenes in the Huacho Sausage, from the Food Markets in Cercado de Lima, is 78%. This is quite high, as it exceeds the values reported in international studies. These results support the conclusion that the Huacho Sausage is a food with a potential risk to the public health.

Abstract The use of antibiotics in aquaculture may cause development of antibiotic resistance among pathogens infecting cultured animals and humans. Therefore, the phages were isolated from the culture environment that can infect the pathogen and resistant bacteria. In this study, there were vibriophage and antibacterial phage isolated from CLOZ andSCKF. The small and circle plaque of vibriophage could become striking by decrease in top agar percentage. The electron micrographs of vibriophage and antibacterial phage belonged to the Podoviridae and Myroviridae family. The phages genome could be cut by HidinIII. The different size fragments were compared and matched to similar genome size of phages from NCBI. For the result, vibriophage may belong to the Picovirinae in Podoviridae. The antibacterial phage would be classified into either Mu-like viruses or unclassified Myoviridae. In the infecting test with (103 PFU/ml), the vibriophage lysing the host cell was not evident. Then, infecting with ϕA, ϕ20 and ϕ70 107 PFU/ml), the ϕA could lyse the cell and test the lowest OD after two hours by infecting. ϕ20 lysed the cell at exponential phase and antibacterial phage ϕ70 could lysed the host cell at different ages after six hours by infecting. A could lyse the cell and test the lowest OD after two hours by infecting. ϕ20 lysed the cell at exponential phase and antibacterial phage ϕ70 could lysed the host cell at different ages after six hours by infecting.

A Differentiation Factor (DF) was purified from rat lung conditioned medium by a four-steps procedure. The DF has a molecular weight of 27000, and an isoelectric point of 4.70. Although DF is stable up to 60°C, it is sensitive to digestion by trypsin, chymotrypsin and subtilisin. DF forms granulocyte colonies in soft agar. Studies using anti-NRK CSF antibody demonstrated that DF is distinct from GM-CSF.

The objectives of this research were to identify the form of Azotobacter as it exists in situ in the soil; to compare its resistance to that of laboratory grown cysts typical of those described in the literature; and to compare its resistance to that of cells grown on dialyzed soil agar. In addition, the morphology of the cells grown on dialyzed soil agar was examined by light and electron microscopy and then compared to the cysts grown on n-butanol Burk's medium. Dipicolinic acid and oxygen uptake rate were measured in cysts and on cells grown on dialyzed soil agar in order to determine whether the cells grown on dialyzed soil agar were endospores or other dormant form and also to measure the respiratory quotient in these cells.