Taraxacum officinale F. H. Wigg, Asteraceae, is frequently misidentified or substituted with Hypochaeris radicata L., Asteraceae (false dandelion). To increase our knowledge of T. officinale and differentiate it from H. radicata, we investigated the two species using a combination of taxonomy, microscopy, and chromatographic studies via fingerprint profiles. Micromorphological characteristics were studied using scanning electron microscopy, while optic light microscopy was used for histochemical observations. Fingerprint profiles were constructed using HPTLC. T. officinale was found to have a morphologically distinct type of pluricellular trichomes that can be used to differentiate the two species, as these structures were not identified in H. radicata samples. Furthermore, two types of laticiferous vessels may also be distinctive characteristics of T. officinale at species level. In addition, the HPTLC data derived from methanolic extracts of H. radicata and T. officinale roots showed clearly different chemical profiles. Thus this study establishes the authenticity of T. officinale, and the observed parameters could help minimize drug substitutions in herbal medicines.

Introducción . Los microorganismos patógenos como Enterobacter cloacae producen betalactamasas que les confieren resistencia frente a los antibióticos betalactámicos; se ha identificado, además, la actividad limitada de los inhibidores enzimáticos, de modo que la única posibilidad de enfrentar la resistencia es el diseño de nuevos fármacos y su uso racional. Objetivo. Evaluar el efecto de la chalcona dihidroxifenil propenona sobre un aislamiento clínico de E. cloacae y sobre la betalactamasa aislada a partir de este microorganismo resistente como un aporte en la búsqueda de compuestos inhibidores de las betalactamasas. Materiales y métodos. Se sintetizó la chalcona dihidroxifenil propenona y se evaluó su efecto sobre el aislamiento clínico de E. cloacae para determinar la concentración inhibitoria mínima mediante el método de microdilución en caldo y con la betalactamasa purificada mediante cromatografía de afinidad se realizaron estudios espectrofotométricos de cinética enzimática. Resultados. La concentración inhibitoria mínima de la dihidroxifenil propenona sobre E. cloacae fue de 35 µg/ml; el porcentaje de recuperación de la betalactamasa a partir del microorganismo fue de 31,75 %; en el estudio cinético se evidenció actividad inhibitoria de acuerdo con los parámetros cinéticos de V max =1,7 x 10 -3 µM/minuto y K M´ =2330 µM. Conclusión. La chalcona dihidroxifenil propenona ejerce su actividad inhibitoria por medio de la interacción con la betalactamasa y, de esta manera, protege la integridad estructural de los antibióticos betalactámicos; dicho efecto sinérgico la convierte en un compuesto promisorio en la búsqueda de alternativas para enfrentar la resistencia bacteriana.

Introduction: Enterobacter cloacae is a pathogenic microorganism with the ability to produce betalactamase enzymes, which makes them resistant to betalactamic antibiotics. Additionally, the limited activity of enzymatic inhibitors has been identified, and, therefore, the design of new drugs and the promotion of their rational use are the only possibilities to overcome this problem. Objective: The aim of this research was to evaluate the effect of dihydroxy-phenyl-propenone on a clinical isolate of E. cloacae , as well as its activity on a betalactamase isolated from this resistant microorganism in order to contribute to the search for new betalactamase inhibitors. Materials and methods: Dihydroxy-phenyl-propenone chalcone was synthesized and evaluated on a clinical isolate of E. cloacae to determine the minimum inhibitory concentration by broth microdilution; once the betalactamase enzyme was purified by affinity chromatography, a spectrophotometric analysis was done to evaluate its kinetic activity. Results: The minimum inhibitory concentration value of dihydroxy-phenyl-propenone on E. cloacae was 35 µg/ml; the recovery percentage of the betalactamase from the microorganism was 31.75% and the kinetic parameters were V max =1.7 x 10 -3 µM/min and K M = 2330 µM, which show an important inhibitory activity. Conclusion: Dihydroxy-phenyl-propenone has shown inhibitory activity on betalactamase enzymes and the ability to protect the chemical integrity of betalactamic antibiotics; this synergistic effect turns it into a promising compound in the search for new alternatives to overcome bacterial resistance.

La "hormiga loca" Paratrechina fulva (Mayr) ha encontrado en el cultivo de cana de azucar las condiciones adecuadas para establecerse y proliferar, lo que ha ocasionado serios problemas al sector. En 1996, se detecto en el Ingenio Risaralda la presencia de un acaro atacando las pupas de la hormiga; diversas investigaciones condujeron a elucidar su biologia, comportamiento y otras relaciones existentes entre el acaro y la hormiga, en orden a determinar la posibilidad de usar el acaro como agente de control de poblaciones de la hormiga loca. El acaro identificado como Macrodinychus sellnicki (Hirschmann) es mirmecofilo y se desarrolla como ectoparasitoide de la pupa succionando los liquidos internos de ella, la cual muere al emerger el adulto. En condiciones de campo, se determino que el acaro puede presentar rangos de parasitismo entre 0 y 93%. Antes de llegar al estado adulto M sellnicki pasa por tres estados de desarrollo: larva, protoninfa y deutoninfa. La duracion de su ciclo de vida fue de 30 dias en promedio contabilizado desde larvas activas hasta la emergencia del adulto. Despues de copuladas las hembras formaron huevos a los siete dias y larvas a los 37, sugiriendo oviviparidad. No se logro observar el proceso de salida de las larvas, las cuales son moviles lo que les permite ubicar a su hospedero. Los dos estados ninfales sufren cambios regresivos en los organos locomotores. M sellnicki tiene una alta capacidad para afectar las poblaciones de P. fulva, pero su reproduccion masiva en laboratorio no fue posible. Su uso, por lo tanto, consistiria en liberaciones inoculativas de material de campo altamente parasitado, en sectores donde se presenten explosiones de hormiga loca y el acaro este ausente.

The crazy ant Paratrechina fulva (Mayr) has conditions found in sugarcane adequate for establishing and proliferating, causing serious problems to growers. In 1996, the presence of a mite attacking crazy ant pupae was detected in Risaralda sugar mill; several investigations were conducted to elucidate its biology, behaviour other relationships between the mite and the ant, in order to determine the possibility of using the mite as a control agent of ant populations. The mite, identify as Macrodinychus sellnicki (Hirschmann), is a myrmecophile and develops as an ectoparasitoid sucking internal fluids of the pupa, which in turn dies when the adult mite emerges. Percent parasitism by mites in the field may vary from 0 to 93%. Before becoming an adult M sellnicki passes through three development stages: larva, protonymph and deutonymph. Mean duration of the life cycle was 30 days from active larva to emerged adult. After copulation, females formed eggs 7 days later and larvae 37 days later, suggesting ovoviviparity. Birth of larvae was not observed; these are active and seek their host. Nymphal stages have regressive development of their locomotion appendages. M sellnicki has a high capacity to affect P. fulva populations but its mass reproduction in laboratory was not possible. Its potential use therefore would be inoculative, consisting of liberations of highly parasitized individuals obtained from the field into areas where there are crazy ant outbreaks but the mite is absent.