Resumen Los objetivos del estudio fueron 1) investigar que fuentes de información usaron los participantes para conocer sobre la COVID-19, 2) evaluar cuál es el nivel de conocimiento que tienen sobre COVID-19 y la atención a pacientes durante la contingencia, y 3) evaluar la percepción de seguridad sobre el regreso a actividades presenciales en la facultad. Estudio transversal. Se aplicó un cuestionario en línea (29 ítems; n=371) que exploró cada objetivo e incluyó una escala de Likert (Alfa de Cronbach de 0.778). Los datos fueron analizados con las pruebas de U de Mann Whitney y con Tau-c de Kendall. La mayoría de los participantes obtuvieron información sobre la COVID-19 a través de la Secretaría de Salud (45.28%), tuvieron un conocimiento bueno sobre las generalidades de la COVID-19 y el 59.3% tuvo un conocimiento excelente sobre la atención a pacientes. La mitad de los encuestados tuvo una percepción de inseguridad en un posible regreso a actividades en la facultad. Hubo diferencia estadística significativa para la asociación entre año escolar y grado de conocimiento (p<0.001) y entre la percepción en la seguridad en el regreso a actividades (muy inseguro, inseguro, seguro y muy seguro) y el grado escolar (P=0.000). Los participantes tuvieron buen conocimiento sobre las generalidades de la COVID-19 y sobre la atención a pacientes en situación de contingencia. La mitad de los EO sienten inseguridad sobre un posible regreso a actividades.

Abstract This study aimed: 1) to investigate sources of information used by students to learn about COVID-19, 2) to investigate levels of knowledge about COVID-19 and about conditions for the treatment of patients during the COVID-19 lockdown, and 3) to evaluate students' perceptions of safety regarding their return to in-person activities at the School of Dentistry. Dental students answered a questionnaire (29 items; n=371) that explored the aims of the study, based on a Likert scale (Cronbach's alpha, 0.778). Data were tested with the Mann-Whitney U test and Kendall's Tau-c. Dental students received information about COVID-19 from the Mexican Health Ministry as their first source (45.28%). Students had good knowledge about the main characteristics of COVID-19, and 59.3% of students had excellent knowledge about the factors relevant to dental treatment of patients. Half of the students said they felt safe regarding a possible return to in-person activities at the dental school, while the other half did not. Statistically significant differences were noted between the students' scholar year and their level of knowledge (P<0.001) and between their perception of safety (very unsafe, unsafe, safe, and very safe) and scholar year (P=0.000). Dental students had good knowledge about COVID-19 and about the dental care for patients during the lockdown. Half of the dental students felt unsafe about a possible return to in-person school activities.

ABSTRACT Varroa destructor is the most harmful and widespread parasite that spreads disease in bees. Eucalyptus spp essential oils (EOs) have proved effective against V. destructor. Additionally, Lavender spp EOs treatment has caused mite mortality rates of 95% to 97% for the same parasite. In this study, 20 mL of each oil or the placebo were distributed on two sheets of papier-mâché located on the frames of the brood chamber inside each hive. The miticidal effects of Lavandula angustifolia and Eucalyptus globulus EOs were analysed. Parasitic load and mite fall were evaluated under field conditions. The mean infestation rate obtained from each of the three treatment groups at the beginning of the study was less than 3.6%. Then, the infestation rate increased gradually in each group until day 36. The infestation rate in the group treated with L. angustifolia was lower than in the control group by over two per cent and never exceeded 10%; the differences between the control group and the L. angustifolia group were statistically significant (P<0.05). In conclusion, L. angustifolia EO provided effective parasite control starting at the second treatment dose. However, E. globulus EO did not show a consistent parasite control. Further studies should consider the evaluation of EOs for the control of V. destructor in different weather conditions and other treatment delivery systems.

Abstract The research was carried out in the state of Nuevo León, Mexico, during 2018, with the aim of isolating and identifying strains of soil microorganisms and evaluating their antagonistic capacity in vitro against citrus pathogens Lasiodiplodia theobromae and Fomitopsis meliae. For the isolation of the microorganisms, 17 rhizosphere samplings were carried out in different locations and types of vegetation; the samples were heat treated and spread by extension in the potato dextrose agar culture medium added with 0.3% yeast extract and 0.3% malt extract (PDLMA). The isolates obtained were preliminarily evaluated by observation and growth comparison. Of 70 isolates, 15 presented antagonistic activity, which showed inhibition percentages of 39-91%. The actinomycete strains M4 R and M1-101, and the fungus M104 (Penicillium citrinum) caused 84, 91 and 85% inhibition respectively against L. theobromae and 83, 91 and 91% respectively against F. meliae. Isolation of bacteria was achieved, actinomycetes and fungi from the soil capable of inhibiting the growth of L. theobromae and F. meliae fungi causing regressive citrus death.

Resumen La investigación fue realizada en el estado de Nuevo León, México, durante el año 2018, con el objetivo de aislar e identificar cepas de microorganismos de suelo y evaluar su capacidad antagónica in vitro frente a los patógenos de cítricos Lasiodiplodia theobromae y Fomitopsis meliae. Para el aislamiento de los microorganismos se realizaron 17 muestreos de rizósfera en diferentes localidades y tipos de vegetación; las muestras se trataron con calor y se sembraron por extensión en el medio de cultivo papa dextrosa agar adicionado con 0.3% de extracto levadura y 0.3% de extracto de malta (PDLMA). Los aislamientos obtenidos se evaluaron preliminarmente por observación y confrontación del crecimiento. De 70 cepas aisladas, 15 presentaron actividad antagónica, las cuales mostraron porcentajes de inhibición de 39-91%. Las cepas de los actinomicetos M4 R y M1-101, y el hongo M104 (Penicillium citrinum) causaron inhibición de 84, 91 y 85% respectivamente contra L. theobromae y de 83, 91 y 91% respectivamente contra F. meliae. Se logró el aislamiento de bacterias, actinomicetos y hongos del suelo capaces de inhibir el crecimiento de los hongos L. theobromae y F. meliae causantes de muerte regresiva de los cítricos.

Abstract Medical schools play a central role in the compilation and development of professional knowledge, which is why they have privileges and resources that are justified only to the extent that they use them to serve the community, particularly those who are most in need. Medical schools social accountability focuses on the training, healthcare provision and research services they offer. The principles of medical education and the structure proposed by the Flexner Report are in crisis due to the COVID-19 pandemic, and redefinition of the social contract is required. This document offers a proposal for medical schools social accountability that includes anticipation of the needs of the community, patient-centered inter-professional care, training of people in the area of health and collaboration between institutions. It highlights the need for a conscious institution that finds new training spaces other than hospitals, where each patient is cared for in a personalized way, with inter-professional training models that consider the student as a person who takes care of him/herself in open collaboration with organizations. Leaders must act now because it is their social responsibility and because it is the right thing to do.

Resumen Las escuelas de medicina desempeñan un papel central en la acumulación y desarrollo del conocimiento profesional, por lo cual poseen privilegios y recursos que se justifican solo en la medida en que los retribuyan a la comunidad, en particular a los más necesitados. La responsabilidad social de las escuelas de medicina se centra en los servicios formativos, asistenciales y de investigación que ofrecen. Los principios de la educación médica y la estructura propuesta por el Informe Flexner están en crisis debido a la pandemia de COVID-19 y se requiere la redefinición del contrato social. El presente documento ofrece una propuesta de responsabilidad social de las escuelas de medicina que incluye previsión de las necesidades de la comunidad, atención interprofesional centrada en el paciente, formación de profesionales en el área de salud y colaboración entre instituciones. Resalta la necesidad de una institución consciente que encuentre nuevos espacios de entrenamiento diferentes al hospitalario, donde se atienda a cada paciente de forma personalizada, con modelos formativos interprofesionales que consideren al alumno como persona que cuida de sí misma en colaboración abierta con las organizaciones. Los líderes deben actuar ya porque es su responsabilidad social y porque es lo correcto.

Abstract The cultivation of citrus fruits is affected by several phytopathogenic fungi, which can cause diseases and reduce their production. The fungus Lasiodiplodia spp. causes regressive death and other symptoms in citrus and other crops in various countries, including Mexico. The objective of this work was to identify isolated fungal strains of citrus trees with symptoms of regressive death and to evaluate their pathogenicity in greenhouse conditions. The isolated fungi were identified based on their morphological characteristics such as Lasiodiplodia theobromae, Fomitopsis meliae and Eutypella citricola, confirmed with PCR amplification and sequencing of the ITS region when compared to the GenBank sequences. In the greenhouse bioassay, it was found that L. theobromae and F. meliae cause symptoms of wilting, descending death and necrotic lesions in the inoculated areas from the fourth day after inoculation in plants of sweet orange variety Valencia. F. meliae + L. theobromae caused more severe damage, causing necrotic lesions of 22 to 27 cm in length, wilt and regressive death and both were reisolated from the lesions produced. E. citricola only produced necrosis around the inoculated area. According to the results of the pathogenicity test, fungi L. theobromae and F. meliae cause regressive citrus death.

Resumen El cultivo de cítricos es afectado por varios hongos fitopatógenos, los cuales pueden causar enfermedades y reducir su producción. El hongo Lasiodiplodia spp. causa muerte regresiva y otros síntomas en cítricos y en otros cultivos en diversos países, incluyendo México. El objetivo de este trabajo fue identificar cepas fúngicas aisladas de árboles de cítricos con síntomas de muerte regresiva y evaluar su patogenicidad en condiciones de invernadero. Los hongos aislados fueron identificados con base en sus características morfológicas como Lasiodiplodia theobromae, Fomitopsis meliae y Eutypella citricola, confirmados con la amplificación por PCR y secuenciación de la región ITS al comparar con las secuencias del GenBank. En el bioensayo de invernadero se comprobó que L. theobromae y F. meliae provocan síntomas de marchitez, muerte descendente y lesiones necróticas en las áreas inoculadas a partir del cuarto día posterior a la inoculación en plantas de naranjo dulce variedad Valencia. F. meliae + L. theobromae causaron daños más severos, provocando lesiones necróticas de 22 a 27 cm de longitud, marchitez y muerte regresiva y ambos fueron reaislados a partir de las lesiones producidas. E. citricola sólo produjo necrosis alrededor del área inoculada. De acuerdo con los resultados de la prueba de patogenicidad, los hongos L. theobromae y F. meliae causan muerte regresiva de los cítricos.

The size of the cerebellum in ultrasound volumes of the fetal brain has shown a high correlation with gestational age, which makes it a valuable feature to detect fetal growth restrictions. Manual annotation of the 3D surface of the cerebellum in an ultrasound volume is a time consuming task, which needs to be performed by a highly trained expert. In order to assist the experts in the evaluation of cerebellar dimensions, we developed an automatic scheme for the segmentation of the 3D surface of the cerebellum in ultrasound volumes, using a spherical harmonics model. In this work we present our validation results on 10 ultrasound volumes in which we have obtained an adequate accuracy in the segmentation of the cerebellum (mean Dice coefficient of 0.689). The method reported shows potential to effectively assist the experts in the assessment of fetal growth in ultrasound volumes.

El tamaño del cerebelo, en un volumen de ultrasonido del cerebro fetal, ha mostrado una alta correlación con la edad gestacional, lo que hace importante a esta medición para la detección de restricciones del crecimiento del feto. La anotación manual de la superficie 3D del cerebelo en un volumen de ultrasonido es una tarea demandante, que debe ser realizada por un experto. Con el propósito de apoyar a los expertos en la evaluación de las dimensiones del cerebelo fetal, hemos desarrollado un método automático para la segmentación de la superficie 3D del cerebelo en volúmenes de ultrasonido, utilizando un modelo de harmónicos esféricos (spherical harmonics). En este trabajo presentamos los resultados de una evaluación del método automático en 10 volúmenes de ultrasonido con los que hemos obtenido un valor adecuado de exactitud (coeficiente promedio de Dice de 0.689). El método reportado tiene potencial para asistir de manera efectiva a los expertos en la evaluación del crecimiento fetal, utilizando volúmenes de ultrasonido.

A propagação in vitro do abacaxizeiro (Ananas comosus L. Merril) resulta na produção de uma grande quantidade de mudas sadias e homogêneas. Apesar dessas vantagens, a necessidade de um longo período de aclimatização onera essa prática agrícola. A aceleração do crescimento das plantas pela inoculação de bactérias diazotróficas endofíticas e epifíticas pode ser útil para diminuir esse período. O objetivo deste trabalho foi avaliar o potencial de 20 estirpes de bactérias diazotróficas em sintetizar indol, solubilizar fosfato de Ca e óxido de Zn e atuar antagonicamente ao fungo fitopatogênico Fusarium subglutinans f. sp. ananas, bem como, posteriormente, avaliar o desempenho do abacaxizeiro 'Vitória' propagado por cultura de tecidos em resposta à inoculação bacteriana durante o período de aclimatização em casa de vegetação. Foram medidas as características de crescimento da parte aérea e do sistema radicular e o conteúdo de nutrientes de folhas do abacaxizeiro. Os resultados mostraram diferenças na capacidade das bactérias de sintetizar indol, solubilizar fosfato de Ca e óxido de Zn e atuar antagonicamente ao Fusarium. Foram também constatadas diferenças na capacidade das bactérias em promover o crescimento da parte aérea e do sistema radicular e o acúmulo de N, P, K, Ca e Mg em folhas do abacaxizeiro. A inoculação das bactérias diazotróficas selecionadas pode promover o crescimento das mudas durante o período de aclimatização, melhorando a adaptação do abacaxizeiro ao ambiente ex vitro

Pineapple (Ananas comosus L. Merrill) in vitro propagation results in the production of a large quantity of healthy and homogeneous plantlets. Despite these advantages, the long time required for acclimatization makes this agricultural practice too costly. Growth acceleration of plantlets by inoculation with endophytic and epiphytic diazotrophic bacteria may be useful to reduce this period. The objectives of this study were to evaluate the potential of 20 diazotrophic bacteria strains in synthesizing indole, solubilizing Ca phosphate and Zn oxide and acting against the fungus Fusarium subglutinans f. sp. ananas, and subsequently, evaluate the performance of pineapple 'Vitória' propagated by tissue culture in response to the application of these isolates during the acclimatization period in a greenhouse. Shoot and root growth characteristics and leaf nutrient content of pineapple were evaluated. Results showed differences in the ability of the bacteria strains to synthesize indole, solubilize Ca phosphate and Zn oxide and act against Fusarium. Differences in the growth-promoting capacity of the shoot and root system of bacteria and leaf accumulation of N, P, K, Ca and Mg in pineapple were also shown. Inoculation with diazotrophic bacteria can promote the growth of plantlets during the acclimatization period, improving the adaptation of pineapple to the ex-vitro environment

It is a need to know optimum concentrations and/or optimum ranges of nutrients useful for correct diagnosis and improvements of nutrient status of cultivated plants. Recognizing the need to develop correct nutritional standards, it is convenient to improve or to ensure the reliability of those already determined. Having in mind that aim, boundary-line approach standards were developed taking into account data acquired from a field experiment to study the effects of three fertilization treatments on yield of Opuntia ficus-indica L. The developed boundary-line approach standards were compared with already developed compositional nutrient diagnosis norms for N, P, K, Ca, and Mg concentrations in one-year old cladodes, and cladodes fresh matter as yield in order to define correct nutrient standards. The developed boundary-line approach optimum nutrient concentrations (associated to estimated maximum yield) for Opuntia ficus-indica L. are: N = 1.42%, P = 0.38%, K = 4.55%, Ca = 2.83% and Mg = 1.41%. Results suggest that boundary-line approach estimated standards could be trustful and that lower and upper concentrations of the boundary-line approach sufficiency nutrient ranges could be also reliable as well as those for compositional nutrient diagnosis norms.

Es necesario conocer las concentraciones óptimas e intervalos óptimos de nutrimentos útiles para el diagnóstico correcto y el mejoramiento de la condición nutrimental de las plantas cultivadas. Reconocer la necesidad de identificar normas nutrimentales correctas, es conveniente para mejorar o garantizar la confiabilidad de las ya definidas. Al tomar en cuenta ese objetivo, la técnica de línea límite se usó para identificar concentraciones óptimas y rangos de suficiencia al 95% del rendimiento máximo al tomar en cuenta los datos obtenidos de un experimento de campo desarrollado con el fin de estudiar los efectos de tres tratamientos de fertilización sobre el rendimiento de Opuntia ficus-indica. Las normas de la técnica de línea límite, producto del presente trabajo, se compararon con las normas de diagnóstico de nutrimento compuesto ya desarrolladas para los casos de concentraciones de N, P, K, Ca y Mg en cladodios de un año de edad, en su relación con materia fresca de cladodios como rendimiento con el fin de identificar normas nutrimentales correctas. Las concentraciones óptimas identificadas con la técnica de línea límite para Opuntia ficus-indica L. son las siguientes: N = 1.42%, P = 0.38%, K = 4.55%, Ca = 2.83% y Mg = 1.41%. Los resultados sugieren que las normas estimadas mediante la técnica de línea límite son confiables; además, las concentraciones inferior y superior de los intervalos de suficiencia de los cinco nutrimentos son tan confiables como las asociadas a las normas de diagnóstico de nutrimento compuesto.

Background and objectives: To analyse the use of the radiological examinations and the adequacy of every request to the guidelines of indication of radiological investigations. Patients and methods: A prospective survey that includes the explorations carried out in 202 patients hospitalised between January and April of 2006. The demographic data, the diagnosis, the radiological exams, the clinical aim of the requests and the requesting department were analysed. The appropriateness was assessed according to the international criteria of adequacy by two experienced physicians. Results: Twenty-seven percent out of the requests of radiological investigations was no adapted to the reference criteria. The requesting department, the type of radiographies and the diagnostic aim of the radiological studies were associated with an appropriate indication (p < 0.0001). Among the radiographies with diagnostic aim, the detection of radiological alterations was associated with a suitable indication of the request (p < 0.0001). Conclusion: The appropriate use of the radiological explorations was similar to other published reports. The inadequate indication seems to be associated with the use of simple radiographic explorations, with follow-up studies and with the requests from Intensive Care Unit.

Fundamento y objetivo: Analizar la utilización de los estudios radiográficos y la adecuación de cada solicitud a las guías de indicación de exámenes radiológicos. Pacientes y métodos: Estudio prospectivo que incluye las exploraciones radiológicas en 202 pacientes hospitalizados entre enero y abril de 2006. Se recogieron los datos demográficos, el diagnóstico, los exámenes radiológicos, el objetivo clínico de la solicitud y el servicio solicitante. La indicación se evaluó por dos médicos en relación a las recomendaciones de las guías internacionales. Resultados: El 27,3% de las solicitudes de las exploraciones radiológicas no se adecuaron a los criterios de indicación. El servicio peticionario, el tipo de estudio radiográfico y el objetivo diagnóstico de la radiografía se asociaron con una indicación apropiada (p < 0,0001). Entre las solicitudes con intención diagnóstica, la detección de alteraciones radiológicas se asoció con una indicación adecuada (p < 0,0001). Conclusión: El uso apropiado de las exploraciones radiológicas fue similar a lo publicado en otros estudios. La indicación inadecuada parece asociarse con el uso de la radiografía simple, con estudios de seguimiento de la enfermedad y con las solicitudes de la Unidad de Medicina Intensiva.

Objective: In the last decades there has been an increasing interest in the manipulation of intestinal microbiota with probiotics for the prevention and treatment of certain paediatric diseases. In addition, it has been suggested that probiotics could play a role in the development of immune system. Recent studies suggest that the administration of two probiotic strains, Lactobacillus coryniformis CECT5711 and Lactobacillus gasseri CECT5714 improves intestinal function of healthy adults and enhances the immune response. Since there are few studies reporting the use of probiotic in children, the main consumers of these products, the aim of the present study was to analyze the effects of the administration of the mentioned probiotic strains in healthy children. Interventions: 30 children (age range 3-12) with no gastrointestinal pathology were included in the study. In addition to their usual diet, during the first 3 weeks they received 200 ml of a conventional yogurt containing Lactobacillus bulgaricus and Streptococcus thermophilus. During the following three weeks this yogurt was substituted for 80 ml of a probiotic product (Max Defensas®, Puleva Food S.L.) containing the same amounts of Streptococcus thermophilus and the L. bulgaricus was substituted by a mixture of the target probiotic strains: L. coryniformis CECT5711 and L. gasseri CECT5714. Samples of faeces and saliva were taken at the beginning of the protocol, at week 3 and at the end of the study. Intestinal microbiota, faecal citotoxicity and the inhibition of Salmonella cholerasusis ssp. cholerasuis adhesion to intestinal mucins by the faeces were analyzed. Finally, IgA concentration was determined in the faecal and saliva samples. Results: Tolerance of the probiotic product was good in all the children included in the study. An increase in faecal lactobacilli counts was shown at the end of the experimental protocol (P < 0,05). In addition citotoxicity of faecal samples was significantly (p < 0.05) reduced after probiotic consumption. The inhibition of S. cholerasuis adhesion to intestinal mucins was significantly higher (P < 0.05) for faecal waters from children in week 6 compared to samples form week 0 and 3. Probiotic consumption was also shown to increase IgA concentration in faeces and saliva (P < 0.05). Conclusions: The consumption of a probiotic product containing L. coryniformis CECT5711 and L. gasseri CECT5714 improves intestinal flora of healthy children, enhancing the defence against gastrointestinal aggressions and infections both by inhibiting pathogen adhesion to intestinal mucins and enhancing the immune function.

Objetivo o antecedente: En las últimas décadas la manipulación de la microbiota intestinal mediante el uso de probióticos ha adquirido un gran interés en el tratamiento y prevención de determinadas patologías infantiles. Además actualmente existen multitud de estudios que demuestran que las bacterias probióticas podrían tener un importante papel en el desarrollo del sistema inmunitario. Estudios recientes sugieren que dos cepas probióticas, Lactobacillus coryniformis CECT5711 y Lactobacillus gasseri CECT5714 mejoran la función intestinal de adultos sanos y potencian la respuesta inmunitaria. Dado que son muy pocos los estudios que analizan el papel de los probióticos en niños sanos, principales consumidores de estos productos, el objetivo del presente trabajo fue analizar los efectos de la administración conjunta de estas dos cepas probióticas en un producto lácteo fermentado en niños sanos. Intervenciones: Se reclutaron 30 niños de entre 3 y 12 años sin patología gastrointestinal conocida. Además de su dieta habitual, durante las 3 primeras semanas los niños recibieron 200 ml de un yogurt convencional que contenía Lactobacillus bulgaricus y Streptococcus thermophilus. A continuación este yogurt se sustituyó por 80 ml de un producto probiótico (Max Defensas® Puleva FOOD S.L.) que contenía la misma cantidad de Streptococcus thermophilus y donde el L. bulgaricus fue substituido por la misma cantidad de una mezcla de las bacterias probióticas objeto del estudio: L. coryniformis CECT5711 y L. gasseri CECT5714. Se tomaron muestras de heces y de saliva al comienzo del estudio, a las 3 semanas y al finalizar el estudio. Durante estas 6 semanas los niños no tomaron otro yogurt o probiótico que no fueran los citados anteriormente. Se analizó la microbiotafecal de los niños, la toxicidad de las aguas fecales y la capacidad de éstas para inhibir la adhesión de Salmonella cholerasusis ssp. cholerasuis a mucinas intestinales. Finalmente se determinó la concentración de IgA en heces y en saliva. Resultados: El consumo del producto probiótico objeto del estudio fue bien tolerado por todos los niños. Se observó un aumento del número de lactobacilos en las heces tras 3 semanas de consumo del probiótico. Además la toxicidad de las aguas fecales fue significativamente inferior tras el consumo del probiótico (P < 0,05). La inhibición de la adhesión de S. cholerasuis a mucinas intestinales fue significativamente (P < 0,05) mayor con las aguas fecales de los niños tras el consumo del probiótico en comparación con los homogeneizados iniciales y los obtenidos tras el consumo del yogurt convencional. Porúltimo, el consumo del probiótico aumentó significativamente la concentración de IgA en las heces y en la saliva (P < 0,05). Conclusiones: La administración de un producto probiótico que contiene L. coryniformis CECT5711 y L. gasserii CECT5714 mejora la flora intestinal de niños sanos, favoreciendo la defensa frente a agresiones e infecciones gastrointestinales por inhibición de la adhesión de patógenos y potenciación de la respuesta inmunitaria.

Detectar a presença da bactéria Leifsonia xyli subsp. xyli em material de propagação da cana-de-açúcar (Saccharum sp.) é importante para direcionar o controle do raquitismo-da-soqueira. Neste trabalho, objetivou-se produzir anticorpo policlonal específico contra Leifsonia xyli subsp. xyli (Lxx), visando utilizá-lo em método sorológico para detecção do patógeno. Para isso, o antígeno foi preparado a partir de células intactas, após lavagem por centrifugação de cultura-pura em tampão fosfato salino 0,01 M (PBS) e diálise em glutaraldeido 2% em PBS. O plano de imunização em coelho consistiu de duas injeções intramusculares da mistura 1:1 do antígeno com adjuvante Freund (completo e incompleto, a intervalos de 21 dias) e duas injeções subcutâneas do antígeno puro, a intervalos de dez dias. O anti-soro foi testado pelo método de Dot Blot com revelação por peroxidase para se determinar: (i) título do anticorpo e (ii) reação contra Lxx, Xanthomonas axonopodis pv. vesicatoria e bactérias endofíticas de cana-de-açúcar (Azospirillum brasilense, A. lipoferum, Herbaspirillum rubrisubalbicans, H. seropedicae e Gluconacetobacter diazotrophicus). A maior diluição analisada do anti-soro 1:20.000 mostrou reação fortemente positiva e específica contra Lxx e ausência de reação contra as demais bactérias. A purificação da fração IgG (Imunoglobulina G) não resultou em melhoria na reatividade e especificidade do anti-soro. Estimou-se o nível de detecção do método a partir de suspensão bacteriana em 2x10(6) células/ml.

To detect the presence of the bacterium Leifsonia xyli subsp. xyli (Lxx) in propagation material is important for the control of the ratoon stunting disease. The objective of this work was to improve a serological method for detection of the pathogen and to evaluate the policlonal antiserum specificity produced against Lxx. The antigen was prepared by resuspending pure culture in PBS and dialyzing it in glutaraldehyde 2% in PBS. The immunization schedule in rabbit constituted of two intramuscularly injections of 1:1 mixture of the antigen: Freund adjuvant (complete and incomplete, with interval of 21 days) and two subcutaneous injections of the antigen, with ten-day intervals. The antiserum was tested by Dot Blot and revealed by peroxidase to determine: (i) title of the antibody, (ii) reaction and specificity against Lxx, Xanthomonas axonopodis pv. vesicatoria and endophytic sugarcane (Saccharum sp.) bacteria (Azospirillum brasilense, A. lipoferum, Hebaspirillum rubrisubalbicans, H. seropedicae, Gluconacetobacter diazotrophicus). The highest dilution of antiserum (1:20.000) presented strong positive reaction and high specificity against Lxx. The purification of the IgG fraction did not improve the antiserum reactivity and specificity. In bacterial cell suspension the level of detection was estimated in 2x10(6) cells/ml.

Sementes infetadas constituem fonte primária de inóculo para epidemias da mancha bacteriana do tomate (Lycopersicon esculentum)que sob condições favoráveis podem resultar em rápido desenvolvimento da doença e severas perdas. O presente trabalho objetivou avaliar a eficiência do tratamento térmico a 70 ºC por 96 h na erradicação de Xanthomonas campestris pv. vesicatoria de sementes de tomate e seu efeito sobre a qualidade fisiológica e estrutura das sementes, por meio de microscopia eletrônica de varredura (MEV). Realizaram-se dois ensaios, e utilizando-se sementes inoculadas pelo método a vácuo com o isolado ENA 4463 a 10(7) ufc/ml em NaCl (0,85%). No primeiro ensaio compararam-se quatro tratamentos: sementes inoculadas (1), sementes inoculadas e tratadas a 70 ºC/96 h em estufa com circulação forçada de ar (2), sementes não inoculadas e não tratadas (3) e sementes não inoculadas e tratadas (70 ºC/96 h) (4). No segundo ensaio, apenas os tratamentos (1), (2) e (3) foram comparados. As amostras foram avaliadas quanto à qualidade fisiológica e recuperação da fitobactéria por meio de extração a vácuo seguido de riscagem em meios semi-seletivos, além de observações em MEV. Constatou-se eficiência de 100% e 99,96% na erradicação da bactéria no primeiro e segundo ensaio, respectivamente. Não houve nenhum efeito do tratamento térmico sobre a germinação. Observações ao MEV, revelaram alterações na estrutura superficial das sementes, com remoção, quebra e fusão de tricomas, além de danos à integridade das células bacterianas associadas à superfície do tegumento.

Infected seed is the primary source of tomato (Lycopersicon esculentum) bacterial spot causing a rapid development of the disease with severe yield losses under favorable environmental conditions. The present work was undertaken to evaluate the effect of heat treatment (70 ºC for 96 h) on germination and seed structure, as well as to determine the efficiency of heat therapy to prevent bacterial growth and disease establishment. Two experiments were carried out using tomato seeds inoculated by vacuum with Xanthomonas campestris pv. vesicatoria strain ENA 4463 adjusted to 10(7) cells.ml-1 followed by air-drying. In the first assay, four treatments were designed as follows: (1) inoculated seeds; (2) inoculation followed by heat treatment (70 ºC/96 h); and two controls, uninoculated seeds without (3) and with (4) heat treatment. In the second assay, three treatments: (1), (2) and (3) were compared. Samples from different treatments were evaluated for the physiological status of the seeds and presence of the bacteria. The latter was tested by recovering the bacteria by vacuum extraction, isolation in semi-selective medium and visualizations though scanning electron microscopy (SEM). The efficiency of the heat treatment as a method to control the disease ranged from 99,96 to 100% for the second and first assay, respectively. Furthermore, there was no significant effect of the heat on seed germination. However, under SEM, heat treated seed showed some superficial structural changes, characterized by a greater number of broken trichomes, and a deposition of trichomes randomly or organized in plates over the seed surface and morphological changes in the bacterial cell shape.

Foram caracterizados fisico-quimicamente ácidos húmicos, obtidos de composto de resíduos sólidos urbanos (AH-CRSU) e de lodo de estação de tratamento de esgoto (AH-LETE), ambos produzidos na cidade do Rio de Janeiro, por meio da análise da composição elementar, acidez total, de dados espectroscópicos (UV-Vis; IV, RMN de 13C-CP/MAS) e microscopia eletrônica de varredura (MEV). A análise das características estruturais revelou diferenças entre os AHs estudados. A presença de sistemas aromáticos foi observada por meio da espectroscopia de UV-Vis, indicando sistemas mais substituídos nos AH-LETE. A espectroscopia na região do infravermelho (IV) mostrou a presença de estruturas alifáticas nos AHs e maior complexidade nos sinais de absorção devida a polissacarídeos nos AH-CRSU. Além disso, foram observados grupos OH, COOH, COO-, CO2NH2, e confirmada a presença de sistemas aromáticos. Com a análise de RMN de 13C-CP/MAS, foi possível verificar as diferenças quantitativas nos diferentes tipos de carbono. Os AH-LETE apresentaram maior quantidade de grupos aromáticos e de COOH. A análise de RMN de 13C-CP/MAS também mostrou presença de polissacarídeos, N em aminoácidos e grupamentos OCH3. O conjunto de propriedades avaliadas permitiu indicar que a fração ácidos húmicos dos resíduos é "do tipo" ou "análoga" aos ácidos húmicos de origem pedogênica.

Physico-chemical characteristics of humic acids obtained from urban waste (AH-CRSU) and sewage (AH-LETE) produced in the city of Rio de Janeiro, were determined through elemental analysis, total acidity, spectroscopic methods and electron scanning microscopy. The analysis of structural traits revealed some differences between the humic acids investigated. The presence of aromatic moieties was confirmed with UV-Vis spectroscopy, with more substituted systems present in the AH-LETE. IR spectroscopy showed aliphatic groups in the AH and as more complex signals due the presence of polysaccharides in AH-CRSU. Furthermore, the presence of COOH, COO-, CO2NH2, OH, was observed apart from aromatic systems. The CP/MAS 13C NMR analysis allowed to observed a higher amount of aromatic and COOH groups. showed the presence of polysaccharides, aminoacid N and OCH3 groups. The results allow to define the humic acids from urban source as of the type or like those of pedogenic origin.

The design of the bronchial tree in mammals has been associated to an adequate flow of gases to the alveoli, a minimal entropy production in the respiratory mechanics and a minimum costs of material and energy. However, the air way is only part of the respiratory system and it must satisfy the requirements of the functional system. Then it must distribute a volume of inspired air on a great surface, inscribed into a fenced volume. The bronchial tree fills the space with its progressive ramification and it shows a fractal like geometry in the decrease of the bronchial diameter. In this study we characterise the topology of the bronchial tree of Rattus norvegicus by means of the fractal dimension, comparing with it of other mammals with different body size: Oryctolagus cuniculli y Homo sapiens. To probe the auto-similarity we also study the effect of the scale factor on the fractal dimension. Our results showed a fractal geometry of the air way of the three species at different scale factors. The bronchial topology was similar in the three species with fractal dimensions from 1.57 to 1.59. Our results are in agreement with the fractal-like geometry of the bronchial diameter, alveolar surface, pulmonary ventilation and blood flow. Some consequences of this type of geometry on the lung physiology are discussed.

RESUMEN: El árbol bronquial de los mamíferos presenta un diseño que se ha asociado con un adecuado flujo de gases a los alvéolos, una mínima producción de entropía en la mecánica respiratoria y con un mínimo costo en materia y energía. Sin embargo, la vía aérea constituye sólo parte del sistema respiratorio y como tal su geometría debe ajustarse a la función de todo el sistema resolviendo el problema de distribuir un volumen de aire inspirado en una gran superficie, dispuesta en un volumen acotado. Así, la topología bronquial exhibe las características de ocupar espacio con su ramificación progresiva y una reducción del diámetro de los bronquios que se ha asociado a una geometría fractal. En este trabajo se caracteriza la topología del árbol bronquial de Rattus norvegicus mediante su dimensión fractal y se compara con otros mamíferos de distinto tamaño: Oryctolagus cuniculli y Homo sapiens. Se estudia además el efecto de la escala para verificar la autosimilitud. Los resultados demuestran una geometría fractal de la vía aérea de las tres especies, que se mantiene a distintas escalas y son una demostración directa de este tipo de geometría. La topología se mantiene invariante en las tres especies, con dimensiones fractales entre 1,57 y 1,59. Los resultados coinciden con otros estudios realizados en la vía aérea, la superficie alveolar, la ventilación y la perfusión pulmonar. Se discuten las consecuencias de este tipo de geometría en el pulmón.