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Resumen La clorhexidina como tratamiento de la enfermedad periodontal ha logrado efectos bactericidas sobre periodontopatógenos y biopelícula oral. Su uso genera efectos adversos, por lo tanto se presentan alternativas naturales con efecto antimicrobiano similar. Los aceites esenciales han demostrado efectividad en el control de la placa dental, sin los efectos adversos de la clorhexidina. El objetivo de este estudio fue determinar el efecto bacteriostático y bactericida del aceite esencial de mandarina contra Fusobacterium nucleatum. Se realizó extracción por expresión del aceite esencial de cáscaras de mandarina (variedades Arrayana y Oneco). Se evaluaron concentraciones al 20%, 40%, 60%, 80% y 100% del aceite esencial diluido en Tween al 0,02%. El efecto bacteriostático y bactericida se determinó por pruebas de sensibilidad antimicrobiana por difusión en disco. Como control positivo se utilizó Clorhexidina 0,2% y agua como control negativo. Se midió halo de inhibición (mm) y se determinó ausencia o presencia de crecimiento bacteriano a partir de unidades formadoras de colonias. Para comparación de proporciones de la actividad bacteriostática y bactericida, se realizó prueba de Fisher y T student (IC 95% p = 0,05). El halo de inhibición a una concentración del 100% mostró comportamiento similar a clorhexidina (p<0,05). Concentraciones al 100% y 80% fueron bactericidas, al 60%, 40% y 20% presentaron comportamiento bacteriostático. No se encontraron diferencias significativas en las proporciones de inhibición entre las dos variedades de mandarina (p>0,05). El uso de aceites esenciales de mandarina podría ser una alternativa complementaria al tratamiento de la enfermedad periodontal.

Abstract Chlorhexidine as a treatment of periodontal disease has achieved bactericidal effects over periodontopathogens and oral biofilm. Its use generates adverse effects; therefore natural alternatives are presented with a similar antimicrobial effect. Essential oils have proved effective in controlling dental plaque without the adverse effects of chlorhexidine. The aim of this study was to determine the bacteriostatic and bactericidal effect of essential oil of tangerine against Fusobacterium nucleatum. The extraction of the essential oil was performed by expression of tangerine peels (Arrayana and Oneco varieties). Concentrations at 20%, 40%, 60%, 80% and 100% of the essential oil diluted in 0,02% Tween were evaluated. The bacteriostatic and bactericidal effect was determined by antimicrobial susceptibility testing by disk diffusion. As a positive control 0,2% chlorhexidine and water as negative control were used. Inhibition zone (mm) was measured and presence or absence of bacterial growth was determined from colony forming units. To compare proportions of bacteriostatic and bactericidal activity, Fisher and T student test (95% CI p = 0,05) were performed. The 100% concentration zone of inhibition showed a similar behavior as chlorhexidine (p <0,05). 100% and 80% concentrations were bactericides, 60%, 40% and 20% showed bacteriostatic behavior. No significant differences between the proportions of inhibition of the two varieties of tangerine (p> 0,05). The use of essential oils of tangerine could be a complementary alternative to treatment of periodontal disease.

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Pentolite is a mixture (1:1) of 2,4,6-trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN), and little is known about its fate in the environment. This study was aimed to determine the dissipation of pentolite in soils under laboratory conditions. Microcosm experiments conducted with two soils demonstrated that dissipation rate of PETN was significantly slower than that of TNT. Interestingly, the dissipation of PETN was enhanced by the presence of TNT, while PETN did not enhanced the dissipation of TNT. Pentolite dissipation rate was significantly faster under biostimulation treatment (addition of carbon source) in soil from the artificial wetland, while no such stimulation was observed in soil from detonation field. In addition, the dissipation rate of TNT and PETN in soil from artificial wetland under biostimulation was significantly faster than the equivalent abiotic control, although it seems that non-biological processes might also be important for the dissipation of TNT and PETN. Transformation of PETN was also slower during establishment of enrichment culture using pentolite as the sole nitrogen source. In addition, transformation of these explosives was gradually reduced and practically stopped after the forth cultures transfer (80 days). DGGE analysis of bacterial communities from these cultures indicates that all consortia were dominated by bacteria from the order Burkholderiales and Rhodanobacter. In conclusion, our results suggest that PETN might be more persistent than TNT.

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La tortuga hicotea (Trachemys callirostris callirostris) es una subespecie sometida a una alta extracción en Colombia, de la cual no se conoce nada sobre su reproducción en zonas altamente alteradas con bajo impacto por la cacería. Para ello, en tres ambientes acuáticos generados por la minería de carbón en la mina del Cerrejón, departamento de La Guajira, estudiamos algunas características reproductivas de la hicotea durante el periodo reproductivo de 2011 (marzo a junio). Solamente en las lagunas de estabilización registramos un éxito de eclosión positivo (56,9 %). En el embalse de minería, la tasa de depredación de 100 % fue el factor limitante del éxito de eclosión, por lo que recomendamos el aislamiento de los nidos del principal depredador (zorro patón: Procyon cancrivorus) y el traslado de nidadas para su incubación ex-situ. La baja anidación registrada en la zona rehabilitada pudo haberse debido a una extracción de hembras adultas, a factores limitantes del hábitat que influyen en el crecimiento de los individuos, o por factores de tipo demográfico. Las diferentes variables estudiadas a nivel de los huevos y los neonatos en los tres sectores, evidencian la posibilidad de que las hembras anidantes posean tamaños mayores que las de otras poblaciones de Colombia sometidas a la cacería. Sin embargo, para establecer el grado de variación geográfica, es necesario determinar la variación temporal de las características reproductivas en la población del Cerrejón.

The Colombian slider turtle (Trachemys callirostris callirostris) is a subspecies under a high level of exploitation in Colombia, of which nothing is known about its reproduction in highly disturbed areas with low hunting pressure. We studied some reproductive traits in three different aquatic environments created by coal mining in the Cerrejon mine, La Guajira department, during part of the reproductive season in 2011 (between March and June). We recorded hatching success (56.9 %) only in the stabilization ponds. In the mining reservoir, the 100 % predation rate was the factor limiting hatching success. The recommended option there is protect the nests from the main predator (Procyon cancrivorus) and the relocation of some of them for ex-situ incubation. The low level of nesting recorded in the rehabilitated area may have been the result of extraction of adult females, but also could be due to habitat limiting factors influencing the growth of individuals, or by demographic factors. Size variables measured for clutches, eggs, and hatchlings at the three study sites, showed the possibility that nesting females are larger than those of other populations subjected to hunting in Colombia. However, to determine the extent of geographic variation when compared to other populations it will be necessary to examine temporal variation in reproductive traits of the Cerrejon population.