Se evaluó el ácido úsnico (1), aislado del liquen Evernia prunastri (Cajamarca-Perú), producto natural conocido por sus actividades biológicas, y, del mismo modo, se evaluó la síntesis de su derivado acil-hidrazona (2), obtenido a partir de una reacción de condensación entre el ácido úsnico y la isoniazida en solución etanólica a reflujo, con un rendimiento global de 95%. Ambos compuestos fueron evaluados y comparados con la isoniazida según su actividad anti-Mycobacterium tuberculosis basada en el ensayo de susceptibilidad mediante el método TEMA. Los resultados mostraron que el compuesto 1 presenta valores de MIC de 16,0 μg/mL frente a las cepas H37Rv, TB DM 97 y MDR DM 1098, mientras que el compuesto 2 presenta valores de MIC de 2,0; 64,0 y 64,0 μg/mL respectivamente.

Background:To successfully colonize the oral cavity, bacteria must adhere directly or indirectly to the oral surfaces available. Fusobacterium nucleatum plays an important role in the development of the oral biofilm community due to its broad adhesion capabilities, serving as a bridge between the members of the oral biofilm community that cannot be directly joined together. The purpose of this study was to identify and localize the proteins associated with the formation of biofilms of Streptococcus gordonii and F. nucleatum. Methods: Multispecies biofilms were identified by amplification of the srtA and radD genes by real-time PCR. Biofilm cells cultured with sucrose were counted. The protein concentrations in the membrane and cytoplasmic fractions were quantified by western blot. Results: The proteins HSP40 and GAPDH were detected in the cytoplasmic fraction of biofilm and F. nucleatum, respectively. The available anti-GAPDH antibody is specific for GAPDH produced by F. nucleatum, which indicated the coaggregation of F. nucleatum on S. gordonii. Conclusions: HSP40 was only detected in the cytoplasmic fraction of the biofilms, making it one of the essential proteins for adherence. This complex set of interactions could have critical implications for the formation and maturation of oral biofilms in vivo and could provide clues to the mechanism behind the distribution of organisms within the human oral cavity.