Browsing by Autor "Patricia Del Portillo"

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Composición y función de la comunidad microbiana relacionada con el ciclaje de nitrógeno en la rizosfera de Solanum tuberosum (BAHUIN) grupo phureja
(2013) Nathalia Flórez-Zapata; Juan Carlos García; Patricia Del Portillo; Silvia Restrepo; Daniel Uribe-Vélez
COMPOSITION AND FUNCTION OF THE MICROBIAL COMMUNITY RELATED WITH THE NITROGEN CYCLING ON THE POTATO RHIZOSPHERE
(LA Referencia, 2013) Nathalia Flórez-Zapata; Juan Carlos García; Patricia Del Portillo; Silvia Restrepo; Daniel Uribe-Vélez
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 microbal[trm1] 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 physical-chemical 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.
<i>Fusarium</i> species detected in onychomycosis in Colombia
(Wiley, 2008) Natalia Castro López; Clemencia Casas; Leticia Sopó; Alejandro Rojas; Patricia Del Portillo; María Caridad Cepero de García; Silvia Restrepo
Fusarium spp. have frequently been isolated from patients with onychomycosis. In Colombia, several studies have shown that Fusarium is the most common non-dermatophyte mould causing onychomycosis and its spread has increased in the past years. In this study, samples were collected in 2003 and 2004 from 137 patients who were diagnosed with onychomycosis caused by Fusarium spp. Three species of Fusarium were identified: Fusarium solani (64.9%), Fusarium oxysporum (32.8%) and Fusarium verticillioides (2.3%). The diseases were more common in women (73%) than in men (27%) and occurred mainly among adults between 31 and 40 years old. The percentage of patients who had received previous treatments was 63.5%. In the last years, new and improved antifungal agents like echinocandins or new triazoles like voriconazole have been developed. For this reason, susceptibility testing using voriconazole was performed, by broth microdilution and disk diffusion. The results showed that F. solani had the highest minimum inhibitory concentration. Using the disk diffusion test, many of the isolates showed variable susceptibility. Genetic diversity of F. oxysporum isolates was determined by random amplified polymorphic DNA. Twenty isolates belonging to different haplotypes were selected for PCR amplification of a region of the gene encoding α-l-arabinofuranosidase B, a specific test to determine if the isolates were F. oxysporum f. sp. dianthi. On the basis of these PCR results, we found that five out of the 20 F. oxysporum isolates corresponded to f. sp. dianthi.