RESUMO

Introduction: Recurrent urinary tract infections (RUTIs) caused by uropathogenic Escherichia coli are costly public health problems impacting patients' quality of life. Aim: In this work, a comparative genomics analysis of three clinical RUTI strains isolated from bladder biopsy specimens was performed. Materials and methods: One hundred seventy-two whole genomes of urinary tract E. coli strains were selected from the NCBI database. The search for virulence factors, fitness genes, regions of interest, and genetic elements associated with resistance was manually carried out. The phenotypic characterization of antibiotic resistance, haemolysis, motility, and biofilm formation was performed. Moreover, adherence and invasion assays with human bladder HTB-5 cells, and transmission electron microscopy (TEM) were performed. Results: The UTI-1_774U and UTI-3_455U/ST1193 strains were associated with the extraintestinal pathotypes, and the UTI-2_245U/ST295 strain was associated with the intestinal pathotype, according to a phylogenetic analysis of 172 E. coli urinary strains. The three RUTI strains were of clinical, epidemiological, and zoonotic relevance. Several resistance genes were found within the plasmids of these strains, and a multidrug resistance phenotype was revealed. Other virulence genes associated with CFT073 were not identified in the three RUTI strains (genes for type 1 and P fimbriae, haemolysin hlyA, and sat toxin). Quantitative adherence analysis showed that UTI-1_774U was significantly (p < 0.0001) more adherent to human bladder HTB-5 cells. Quantitative invasion analysis showed that UTI-2_245U was significantly more invasive than the control strains. No haemolysis or biofilm activity was detected in the three RUTI strains. The TEM micrographs showed the presence of short and thin fimbriae only in the UTI-2_245U strain. Conclusion: The high variability and genetic diversity of the RUTI strains indicate that are a mosaic of virulence, resistance, and fitness genes that could promote recurrence in susceptible patients.

RESUMO

Selenium is commonly used as an antioxidant in a serum-free culture medium setting. However, lycopene has emerged as a potent antioxidant being twice as efficient as ß-carotene and 10 times as efficient as α-tocopherol with beneficial effects when supplemented in a serum-free maturation medium. Here, we aimed to evaluate the effect of lycopene supplementation in a serum-free culture medium on blastocyst development and quality. After in vitro maturation and fertilization, presumed zygotes were cultured in groups of 25 in 50 µl droplets of synthetic oviductal fluid. Culture medium supplementation was done using four experimental groups: insulin, transferrin, selenium (ITS, control); ITS + DMSO (diluent control); ITS + DMSO-lycopene 0.1 µM (ITSL); and IT + DMSO-lycopene 0.1 µM (ITL). DMSO was used as a diluent for lycopene. Blastocyst development among experimental groups was fitted in mixed-effects models, and blastocyst quality parameters (assessed via differential apoptotic staining) were evaluated in mixed linear regression models. The cleavage (85.3 ± 2.4, 82.6 ± 2.7, 86 ± 2.3 and 86.4 ± 2.3% for control, diluent control, ITSL and ITL, respectively) and day 8 blastocyst rates (37.4 ± 3.3, 36.9 ± 3.4, 39.7 ± 3.3 and 46.2 ± 3.4% for control, diluent control, ITSL and ITL, respectively) were not different (p > .1) among experimental groups. Embryos produced in the ITL group resulted in blastocysts with higher total cell numbers (TCN; 141 ± 19.2), inner cell mass (ICM; 65.3 ± 11.6) and trophectoderm cells (TE; 75.2 ± 8.8) compared with the control (129 ± 19.2, 56.3 ± 11.6 and 72.7 ± 8.8, for TCN, ICM and TE; p < .01, respectively). Lycopene-supplemented groups (ITSL and ITL) resulted in blastocysts with similar TCN, ICM and TE (p > .2). The number of apoptotic cells was not different among experimental groups (p > .1). Lycopene supplementation to the culture medium only produced a numerical increase in the blastocyst rate but replacing selenium with lycopene in a serum-free culture medium resulted in blastocysts with more cells.

Assuntos

RESUMO

Background and study aims Probe-based confocal laser endomicroscopy (pCLE) can provide high magnification to evaluate chronic atrophic gastritis (CAG), but the current pCLE criteria are qualitative and prone to variability. We aimed to propose a quantitative CAG criterion based on pCLE to distinguish non-atrophic gastritis (NAG) from CAG. Patients and methods This observational, exploratory pilot study included patients with NAG and CAG evaluated via esophagogastroduodenoscopy, pCLE, and histology. We measured the gastric glands density, gastric gland area, and inter-glandular distance during pCLE. Results Thirty-nine patients (30/39 with CAG) were included. In total, 194 glands were measured by pCLE, and 18301 were measured by histology, with a median of five glands per NAG patient and 4.5 per CAG patient; pCLE moderately correlate with histology (rho = 0.307; P  = 0.087). A gland area of 1890-9105 µm 2 and an inter-glandular distance of 12 to 72 µm based on the values observed in the NAG patients were considered normal. The proposed pCLE-based CAG criteria were as follows: a) glands density < 5; b) gland area < 1/16 the pCLE field area (< 1890 µm 2 ) or > 1/4 the pCLE field area (> 9105 µm 2 ); or c) inter-glandular distance < 12 or > 72 µm; CAG was diagnosed by the presence of at least one criterion. The proposed criteria discriminated CAG with a ranged sensitivity of 76.9 % to 92.3 %, a negative predictive value of 66.6 % to 80.0 %, and 69.6 % to 73.9% accuracy. Conclusions The proposed pCLE criteria offer an accurate quantitative measurement of CAG with high sensitivity and excellent interobserver agreement. Larger studies are needed to validate the proposed criteria.

RESUMO

Rice (Oryza sativa L.) is a staple food for more than two billion people worldwide. Its cultivation demands large amounts of nutrients, particularly nitrogen and phosphorus (P). Consequently, low availability of these nutrients in the soil has led to the use of chemical fertilizers, generating increases in production costs and environmental damage. Soil host microorganisms known as plant growth-promoting rhizobacteria (PGPR) colonize the rhizosphere and facilitate the uptake of nutrients by the plants. In this study, rice seeds inoculated with PGPR were grown for 30 days in an inert substrate and fertilized with modified Hoagland nutrient solution with phosphate rock as a source of P. Treatments were repeated over time, obtaining five isolates which significantly increased plant length by up to 56% and dry weight of stems and roots up to 45% and 169% respectively relative to an uninoculated control. Selected strains showed in vitro tri-calcium phosphate solubilizing activity, mineralizing phytate activity, and phosphate release from rice straw (RS). Based on the above criteria, three isolates (IBUN-02755, -02,704 and -02,724) that contained ß propeller phytase (BPP) genes, were selected to evaluate their effect as PGPR in rice seedlings. These were planted in a soil amended with RS under greenhouse conditions. The results showed that selected Bacillus spp. strains significantly increased plant length and dry weight or increased plant phosphate uptake up to two times compared to an un-inoculated control. This suggests that selected strains may have a capacity as PGPR using RS as carbon and a P amendment.

Assuntos

RESUMO

RESUMEN Algunos Bacillus spp. promotores de crecimiento vegetal son microorganismos reconocidos como agentes de control biológico que forman una estructura de resistencia denominada endospora, que les permite sobrevivir en ambientes hostiles y estar en casi todos los agroecosistemas. Estos microorganismos han sido reportados como alternativa al uso de agroquímicos. Sus mecanismos de acción se pueden dividir en: producción de compuestos antimicrobianos, como son péptidos de síntesis no ribosomal (NRPs) y policétidos (PKs); producción de hormonas, capacidad de colonización, formación de biopelículas y competencia por espacio y nutrientes; síntesis de enzimas líticas como quitinasas, glucanasas, protesasas y acil homoserin lactonasas (AHSL); producción de compuestos orgánicos volátiles (VOCs); e inducción de resistencia sistémica (ISR). Estos mecanismos han sido reportados en la literatura en diversos estudios, principalmente llevados a cabo a nivel in vitro. Sin embargo, son pocos los estudios que contemplan la interacción dentro del sistema tritrófico: planta - microorganismos patógenos - Bacillus sp. (agente biocontrolador), a nivel in vivo. Es importante destacar que la actividad biocontroladora de los Bacillus es diferente cuando se estudia bajo condiciones de laboratorio, las cuales están sesgadas para lograr la máxima expresión de los mecanismos de acción. Por otra parte, a nivel in vivo, la interacción con la planta y el patógeno juegan un papel fundamental en la expresión de dichos mecanismos de acción, siendo esta más cercana a la situación real de campo. Esta revisión se centra en los mecanismos de acción de los Bacillus promotores de crecimiento vegetal, expresados bajo la interacción con la planta y el patógeno.

ABSTRACT Some Bacillus spp. plant growth promoters are microorganisms recognized as biological control agents, which form a resistance structure called endospore, which allows them to survive in hostile environments and be in almost all agroecosystems. These microorganisms have been reported as an alternative to the use of agrochemicals. Its mechanisms of action can be divided into: production of antimicrobial compounds, such as non-ribosomal peptides (NRPs) and polyketides (PKs); hormone production, colonization capacity, biofilm formation and competition for space and nutrients; synthesis of lytic enzymes such as chitinases, glucanases, protesases and acyl homoserin lactonases (AHSL); production of volatile organic compounds (VOCs); and induction of systemic resistance (SRI). These mechanisms have been reported in the literature in several studies, mainly carried out in vitro. However, there are few studies that contemplate the interaction within the tritrophic system: plant - pathogenic microorganisms -Bacillus sp. (biocontrol agent), in vivo level. It is important to note that the Bacillus biocontrol activity is different when studied under laboratory conditions, which are biased to achieve maximum expression of the mechanisms of action. On the other hand, at the in vivo level, the interaction with the plant and the pathogen play a fundamental role in the expression of said mechanisms of action, being this closer to the real field situation. This review focuses on the mechanisms of action of the Bacillus promoters of plant growth, expressed under the interaction with the plant and the pathogen.

RESUMO

Rice world production is affected due to the growing impact of diseases such as bacterial panicle blight, produced by Burkholderia glumae. The pathogen-induced symptoms include seedling rot, grain rot and leaf-sheath browning in rice plants. It is currently recognized the entrance of this pathogen to the plant, from infected seeds and from environmental sources of the microorganism. However, it is still not fully elucidated the dynamics and permanence of the pathogen in the plant, from its entry until the development of disease symptoms in seedlings or panicles. In this work it was evaluated the infection of B. glumae rice plants, starting from inoculated seeds and substrates, and its subsequent monitoring after infection. Various organs of the plant during the vegetative stage and until the beginning of the reproductive stage, were evaluated. In both inoculation models, the bacteria was maintained in the plant as an endophyte between 1 × 101 and 1 × 105 cfu of B. glumae.g-1 of plant throughout the vegetative stage. An increase of bacterial population towards initiation of the panicle was observed, and in the maturity of the grain, an endophyte population was identified in the flag leaf at 1 × 106 cfu of B. glumae.g-1 fresh weight of rice plant, conducting towards the symptoms of bacterial panicle blight. The results found, suggest that B. glumae in rice plants developed from infected seeds or from the substrate, can colonize seedlings, establishing and maintaining a bacterial population over time, using rice plants as habitat to survive endophyticly until formation of bacterial panicle blight symptoms.

RESUMO

Resumen El tamo de arroz es uno de los residuos agrícolas lignocelulósicos más abundantes en el planeta, luego de los residuos producidos por los cultivos de maíz y trigo, con una producción mundial estimada de 1000 millones de toneladas según estadísticas de la FAO. En el contexto de la agricultura moderna es determinante lograr un manejo ambientalmente sostenible de este recurso mediante su incorporación al suelo, de tal forma que se logre el reciclaje de nutrientes, evitando la incorporación de patógenos al sistema y la inmovilización de elementos como el nitrógeno por la comunidad microbiana. El objetivo de este trabajo consistió en la evaluación de un inoculo microbiano mixto a partir de productos comerciales basados en hongos del género Trichoderma y bacterias aerobias formadoras de endosporas, con potencial degradador del tamo de arroz, así como el empleo de bacterias promotoras de crecimiento vegetal al momento de la siembra, que pudieran aprovechar los nutrientes del proceso de descomposición del tamo de arroz, potenciando su actividad biológica. Los tratamientos fueron evaluados bajo diferentes relaciones C:N del tamo de arroz que favorecieran el proceso de degradación, mediante la adición de nitrógeno inorgánico. Los resultados del trabajo permitieron identificar que la aplicación de una enmienda de nitrógeno a una relación C:N 35 más una dosis adicional de urea al momento de la siembra de las semillas de arroz, fue el tratamiento más adecuado para potenciar el efecto de los microorganismos e incrementar las variables agronómicas obtenidas mediante un esquema de fertilización convencional del cultivo.

Abstract Rice straw is one of the most abundant lignocellulosic agricultural residues on the world, after residues produced by maize and wheat crops, with an estimated global production of 1000 million tones according to FAO statistics. In the context of modern agriculture, it is essential to achieve an environmentally sustainable management of this resource, through the incorporation of rice straw into the soil, in order to achieve nutrient recycling avoiding the incorporation of pathogens into the system and the losses of nitrogen due to soil microbial biomass immobilization. In this context, the objective of this work consisted in the evaluation of a mixed microbial inoculum with degrading potential of rice straw from commercial products based on the fungus Trichoderma spp. and aerobic endospore forming bacteria. It was also used a plant growth promoting bacteria at the time of planting, in order to take advantage of nutrients released from RS decomposition and improve its biological activity. These microbial treatments, were evaluated at different concentrations of inorganic nitrogen amendments that allowed different levels of rice straw´s C:N ratio, favoring the degradation process. Overall results allowed to identify that the application of a nitrogen amendment to rice straw up to C:N 35, plus an additional dose of urea at the time of rice seeds planting, was the most adequate treatment to potentiate the effect of the microorganisms and to increase or maintain the agronomic variables obtained through a conventional fertilization management of the crop.

RESUMO

Between 2014 and 2016 more than 3,800 imported human cases of chikungunya fever in Florida highlight the high risk for local transmission. To examine the potential for sustained local transmission of chikungunya virus (CHIKV) in Florida we tested whether local populations of Aedes aegypti and Aedes albopictus show differences in susceptibility to infection and transmission to two emergent lineages of CHIKV, Indian Ocean (IOC) and Asian genotypes (AC) in laboratory experiments. All examined populations of Ae. aegypti and Ae. albopictus mosquitoes displayed susceptibility to infection, rapid viral dissemination into the hemocoel, and transmission for both emergent lineages of CHIKV. Aedes albopictus had higher disseminated infection and transmission of IOC sooner after ingesting CHIKV infected blood than Ae. aegypti. Aedes aegypti had higher disseminated infection and transmission later during infection with AC than Ae. albopictus. Viral dissemination and transmission of AC declined during the extrinsic incubation period, suggesting that transmission risk declines with length of infection. Interestingly, the reduction in transmission of AC was less in Ae. aegypti than Ae. albopictus, suggesting that older Ae. aegypti females are relatively more competent vectors than similar aged Ae. albopictus females. Aedes aegypti originating from the Dominican Republic had viral dissemination and transmission rates for IOC and AC strains that were lower than for Florida vectors. We identified small-scale geographic variation in vector competence among Ae. aegypti and Ae. albopictus that may contribute to regional differences in risk of CHIKV transmission in Florida.

Assuntos

RESUMO

Los sistemas productivos de Rosas de corte para exportación poseen retos importantes debido a la presencia de diversos agentes fitopatógenos, siendo Botrytis cinerea uno de los más relevantes debido a su persistencia y número de hospederos alternativos. Los mercados internacionales son muy exigentes en el manejo ambientalmente sostenible de los cultivos, por lo que se ha hecho presión para la implementación de estrategias de control biológico de enfermedades. La levadura filosferica Rhodotorula mucilaginosa (Lv20) con potencial biocontrolador contra B. cinérea, fue empleada en este estudio con el objeto de generar un prototipo de formulación en base sólida con el fin de lograr una estabilidad de la actividad y viabilidad celular a través del tiempo. El empleo de mezclas de polímeros sintéticos y de origen natural permitió mantener la viabilidad de esta cepa durante 90 días a unos niveles de 1,90x10(9) células.mL-1 a una temperatura de 25°C en una formulación líquida. Así mismo, el prototipo de formulación, empleando manitol como agente nucleador en una formulación sólida de tipo granulada, logró una viabilidad celular de 1.2x10(8) células.gr-1 a los 90 días de almacenamiento a 4°C, logrando mantener una actividad biocontroladora igual a la cepa fresca sin formular o recién formulada. Estos resultados obtenidos permiten sugerir que los prototipos de formulación empleando como principio activo la levadura R. mucilaginosa, son una alternativa promisoria para el control de B. cinerea en la post cosecha de rosas variedad véndela.

Productive systems of cut roses for exportation, have important challenges due to the presence of various plant pathogens in such crops. Botrytis cinerea is one of the most important pathogen microorganism because of its persistence and number of alternative hosts plants. International markets are very demanding in terms of environmentally sustainable crop management, which has forced for the implementation of strategies for biological control of diseases. The phyllosphere yeast Rhodotorula mucilaginous (Lv20) with biocontrol potential against B. cinerea, was employed in this study in order to generate a solid prototype formulation to achieve both, the stability of its activity and cell viability over time. The use of the mix of synthetic and naturally occurring polymers allowed to maintain the viability of this strain for 90 days at 1,90x10(9) células.mL-1 at a 25 ° C in a liquid formulation. Likewise, the prototype formulation using mannitol as a nucleating agent in a granular solid formulation, allowed obtaining a cell viability of 1.2x10(8) células.gr-1 after 90 days of storage at 4 °C, maintaining a biocontrol activity equal to the fresh strain with or without formulation. These results allow us to suggest that the formulation prototypes using R. mucilaginous yeast, is a promising alternative for the control of B. cinerea in post-harvest management of roses.

RESUMO

Arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing Pseudomonas bacteria (PSB) could potentially interact synergistically because PSB solubilize phosphate into a form that AMF can absorb and transport to the plant. However, very little is known about the interactions between these two groups of microorganisms and how they influence the growth of each other. We tested whether different strains of bacteria, that have the capacity to solubilize phosphate, are able to grow along AMF hyphae and differentially influence the growth of AMF both outside the roots of carrot in in vitro conditions and inside the roots of potato in the presence of a microbial community. We found strong effects of AMF on the growth of the different bacterial strains. Different bacterial strains also had very strong effects on the growth of AMF extraradical hyphae outside the roots of carrot and on colonization of potato roots by AMF. The differential effects on colonization occurred in the presence of a microbial community. Our results show that these two important groups of rhizosphere microorganisms indeed interact with each other. Such interactions could potentially lead to synergistic effects between the two groups but this could depend on whether the bacteria truly solubilize phosphate in the rhizosphere in the presence of microbial communities.

Assuntos

RESUMO

Hepatitis E virus (HEV) is the viral agent that produces most cases of acute hepatitis worldwide. Four genotypes and 24 subtypes of HEV have been identified. Presence of viral strains in pigs suggests this species is a reservoir for HEV. A case of Hepatitis E in humans has been reported in Antioquia, the largest pig producer and pork consumer province in Colombia. This study investigated the presence of HEV in pigs from several swine farms in Antioquia by looking for anti-HEV antibodies and viral RNA in pig feces. Serological tests were performed for detecting IgG and IgM anti-HEV. Molecular assays (RT-PCR) were also used for detecting the ORF-1 marker of HEV viral genome. These procedures were performed on 210 animals from 30 pig farms. Presence of antibodies and molecular analysis were organized by frequencies and analyzed using the R software (version 2.15.2). 100% of the samples were positive for IgG antibodies, while 57% of the samples were positive for IgM antibodies. According to the molecular analysis, 26% of pig feces had genetic material from HEV. This study demonstrates exposure and circulation of HEV in pig farms of Antioquia.

La Hepatitis E es una enfermedad producida por el Virus de Hepatitis E (HEV), considerado el agente vírico con mayor producción de hepatitis agudas alrededor del mundo. Se han determinado 4 genotipos y 24 subtipos de HEV. La presencia de cepas virales tanto en humanos como en otras especies, ha sugerido que existen reservorios animales para HEV, entre los cuales el cerdo juega un papel importante. En Antioquia se ha reportado un caso de Hepatitis E en humanos. Teniendo en cuenta que este departamento es el principal productor y consumidor de cerdos en Colombia, se investigó la presencia de este virus en los cerdos de diferentes granjas porcícolas, con el fin de determinar anticuerpos anti-HEV y RNA viral en heces porcinas. Para lograr esto, se realizaron pruebas serológicas para la detección de anticuerpos IgG e IgM anti-HEV, y pruebas moleculares (RT-PCR) para la detección del marcador ORF-1 del genoma viral de HEV. Estos procedimientos se realizaron en 210 animales de 30 granjas porcícolas de Antioquia. La presencia de anticuerpos y análisis moleculares en los cerdos, se determinaron por frecuencias y se analizaron mediante el software R versión 2.15.2. El 100% de las muestras fueron positivas para anticuerpos IgG; mientras que para anticuerpos IgM, los positivos representaron el 57% de las muestras evaluadas. El análisis molecular determinó que el 26% de los cerdos presentó material genético de HEV en sus heces. Esta información demuestra la exposición y la circulación de HEV en cerdos de las granjas evaluadas en municipios de Antioquia.

A hepatite E é uma doença produzida pelo vírus da hepatite E (HEV), considerado o agente virulento com maior produção de hepatites agudas ao redor do mundo. Tem se determinado quatro genótipos e 24 subtipos de HEV. A presença de cepas virais tanto em humanos quanto em outras espécies, tem sugerido que existem reservatórios animais para HEV, entre os quais o suíno tem grande importância. Em Antioquia tem se reportado um caso de hepatite E em humanos. Tendo de presente que este departamento é o principal produtor e consumidor de suínos na Colômbia, pesquisou-se a presença deste vírus em suínos de diferentes granjas suínas, com o fim de determinar anticorpos anti-HEV e RNA viral em fezes porcinas. Para lograr isto, realizaram-se testes serológicos para a detecção de anticorpos IgG e IgM anti-HEV e testes moleculares (RT-PCR) para a detecção do marcador ORF-1 do genoma viral de HEV. Estes procedimentos realizaram-se em 210 animais de 30 granjas suínas em Antioquia. A presença de anticorpos e as análises moleculares nos suínos, determinaram-se por frequências e se analisaram mediante o software R Versão 2.15.2. O 100% das amostras foram positivas para anticorpos IgG; enquanto que para anticorpos IgM os positivos representaram o 57% das amostras avaliadas. O analise molecular determinou que o 26% dos suínos apresentou material genético de HEV em suas fezes. Esta informação demonstra a exposição e circulação de HEV em suínos das granjas avaliadas em municípios de Antioquia, Colômbia.

RESUMO

BACKGROUND: The concept of deterioration of nutrition status in inpatient children, also called nutrition deterioration (ND), has gained widespread importance and is described as significant weight loss during hospitalization periods. Our main purpose was to determine the incidence of ND in nonseriously ill children younger than age 5 years admitted as inpatients and explore the presence of associated factors. MATERIALS AND METHODS: This descriptive study analyzed a prospective cohort of hospitalized children. We considered a significant weight loss of >2% or >0.25 SD in body mass index with respect to the admission weight. The correspondence between the 2 methods was assessed. The frequency of some clinical variables and its association with the outcome was explored. RESULTS: The incidence of ND was 28.5% with at least 1 of the 2 methods of detection and was 20% with both definitions. The correlation between both methods was high (κ = 0.79). In children with ND, results were statistically significant in those with 5 or more stools a day, those hospitalized 5 or more days, and patients with lower respiratory tract disease. CONCLUSIONS: The incidence of ND was higher than that reported in the literature in children with nonserious disease. Diarrhea, lower respiratory tract disease, and hospital length of stay seem to be associated with these results. More studies are required to establish associations with those factors for an early detection of children at risk and for early interventions.

Assuntos

RESUMO

In the S. tuberosum group phureja crops, mineral fertilizer and organic amendments are applied to meet the plants´ nutritional demands, however the effect of such practices on the associated rizospheric microbial communities are still unknown. Nitrogen plays an important role in agricultural production, and a great diversity of microorganisms regulates its transformation in the soil, affecting its availability for the plant. The aim of this study was to assess the structure of microbial communities related with the N cycle of S. tuberosum group phureja rizospheric soil samples, with contrasting physical-chemical properties and fertilization strategy. Few significant differences between the community composition at the phylum level were found, only Planctomycetes phylum was different between samples of different soil type and fertilization strategy. However, the analysis of nitrogen-associated functional groups made by ribotyping characterization, grouped soils in terms of such variables in a similar way to the physical-chemical properties. Major differences between soil samples were typified by higher percentages of the ribotypes from nitrite oxidation, nitrogen fixation and denitrification on organic amendment soils. Our results suggest that, the dominant rhizosphere microbial composition is very similar between soils, possibly as a result of population´s selection mediated by the rhizosphere effect. However, agricultural management practices in addition to edaphic properties of sampled areas, appear to affect some functional groups associated with the nitrogen cycling, due to differences found on soil´s physicalchemical properties, like the concentration of ammonium that seems to have an effect regulating the distribution and activity of nitrogen related functional groups in the S. tuberosum rhizosphere.

Fertilización mineral y enmiendas orgánicas son aplicadas para satisfacer las demandas nutricionales de los cultivos de S. tuberosum grupo phureja . Sin embargo, el efecto de esas prácticas sobre la comunidad microbiana asociada a la rizósfera aún no se conocen. El nitrógeno juega un papel importante en la producción agrícola y una gran diversidad de microorganismos regulan su transformación en el suelo, afectando su disponibilidad para la planta. El objeto de este estudio fue determinar la composición de la comunidad microbiana de la rizósfera de S. tuberosum grupo phureja , asociada con el ciclo del nitrógeno, en muestras de suelo contrastantes en sus propiedades fisicoquímicas y estrategia de fertilización. Pocas diferencias significativas entre la composición de la comunidad microbiana a nivel de phylum fueron encontradas, Í°nicamente el phylum Planctomycetes fue diferente entre las muestras de suelos con estrategias de fertilización diferentes. Sin embargo, el análisis de grupos funcionales asociados al nitrógeno llevado a cabo por la caracterización de ribotipificación, agrupó los suelos en términos de esas variables en una forma similar a las propiedades fisicoquímicas del suelo. Diferencias mayores entre las muestras de suelo fueron tipificadas por los altos porcentajes de ribotipos asociados a la oxidación de nitrito, fijación de nitrógeno y denitrificación sobre los suelos con enmiendas orgánicas. Nuestros resultados sugieren que la composición microbiana dominante es muy similar entre suelos, posiblemente como resultado de la selección de poblaciones mediada por el efecto rizosférico. Sin embargo, las prácticas del manejo agrícola en conjunto con las propiedades del suelo en las áreas muestreadas, parecen afectar algunos grupos funcionales asociados con el ciclo de nitrógeno, debido a las diferencias encontradas en las propiedades fisicoquímicas del suelo, como la concentración de amonio que parece tener un efecto regulando la distribución y actividad de los grupos funcionales relacionados con el ciclo del nitrógeno en la rizosfera de S. tuberosum.

RESUMO

Mycosphaerella fijiensis is the etiological agent of Black Sigatoka, a fungal disease that affects production of banana and plantain crops in tropical regions. The sizes of cultivable epiphytic and endophytic bacterial populations, aerobic endospore forming bacteria (AEFB), and antagonist bacteria against M. fijiensis isolated from three Musa spp. cultivars from Urabá (Colombia) were studied, in order to find a suitable screening strategy to isolate antagonistic bacteria. Most of the variability found in the epiphytic and endophytic bacterial community sizes among fruit trees was explained by the cultivar differences. We found population sizes ranging from 1.25 × 10(3) to 9.64 × 10(5) CFU/g of fresh leaf and found that 44 % of total cultivable bacteria belong to the AEFB group. We isolated 648 AEFB from three different cultivars and assessed their antagonistic activity against M. fijiensis using the cell-free supernatant obtained from bacterial liquid cultures in three different in vitro assays. Five percent of those bacteria showed higher percent inhibition than the positive control Bacillus subtilis UA321 has (percent inhibition = 84 ± 5) in the screening phase. Therefore, they were selected as antagonistic bacteria against the pathogen. The strains with the highest percentage of antagonism were found in older leaves for the three cultivars, given support to recommend this group of leaves for future samplings. Some of these isolated bacteria affected the mycelium and ascospores morphology of the fungus. They also presented in vitro characteristics related to a successful colonization of the phylloplane such as indolic compounds, surfactant production, and biofilm formation, which makes them possible, potential candidates as biological control agents.

Assuntos

RESUMO

Left ventricular aneurysm (LVA) describes a region of ventricular wall that is thinner than the adjacent myocardial segments, balloons outward and exhibits either akinesis or dyskinesis. Congenital LVA is diagnosed by exclusion with a very low incidence, especially in adult patients with very few cases reported. Clinically, most congenital LVA are asymptomatic. The most common complaints are typical angina or atypical chest pain followed by syncope and heart rhythm disturbances. We describe the case of a 26-year-old-woman that presented with monomorphic sustained ventricular tachycardia as a first manifestation of congenital LVA. Successful endoventricular circular patch placement, or Dor procedure was performed. Successful substrate modification for arrhythmia development was performed and confirmed by an electrophysiological study. This would constitute the first case of this nature reported in Puerto Rico.

Assuntos

RESUMO

El libro Propiedad intelectual en la era de los cultivos transgénicos consta de nueve capítulos en los cuales el profesor Alejandro Chaparro y varios miembros de su grupo de investigación desarrollan en una estructura clara y comprensible el tema de la propiedad intelectual en el área de la Biotecnología. Este es un tema de gran relevancia para investigadores nacionales e internacionales en el área de ciencias de la vida, que pretendan hacer una contribución al conocimiento de la diversidad de nuestro país...

Assuntos

RESUMO

Con el fin de describir los patrones esqueléticos para la maclusión clase III se tomó una muestra de 72 pacientes entre 6 y 12 años de las clínicas odontológicas de la Universidad El Bosque y el CIEO; con padres y abuelos Colombianos, características raciales de mestizos, sin historia de hábitos orales, ni patologías craneofaciales y sin antecedentes de tratamientos de ortodonciau ortopedia. Se les tomó una radiografía de perfil y se estudiaron 24 variables cefalométricas mediante los análisis de Harvord, Steiner, Mc Namara y Downs. Éstas fueron comparadas con un patrón de normalidad (clase I) de una muestra representativa para Santafé de Bogotá. Las variables que presentaron mayores diferencias significativas en cuanto a sexo fueron: longitud maxilar, diferencia maxilo-mandibular y altura facial inferior "Harvord", ángulos interincisal y goniaco "Steiner" y altura facial inferior "Mc Namara". Se observaron diferencias estadísticamente significativas según la edad para las siguientes variables: longitud maxilar, mandibular y diferencia maxilo-mandibular "Harvord", SNB "Steiner", longitud mandibular y diferencia maxilo-mandibular "McNamara" y ángulo de la converjidad "Downs". Los sujetos de maloclusión clase III presentan una combinación de mandíbula normal con un maxilar normal en un 20.4, retrusión maxilar y protrusión mandibular en un 23.6 y 19 con retrusión mandibular y maxilar.

Assuntos

Assuntos

Assuntos