The development of new strategies to reduce the use of traditional antibiotics has been a topic of global interest due to the resistance generated by multiresistant microorganisms, including Escherichia coli, as etiological agents of various diseases. Antimicrobial peptides are presented as an alternative for the treatment of infectious diseases caused by this type of microorganism. The Ib−M1 peptide meets the requirements to be used as an antimicrobial compound. However, it is necessary to use strategies that generate protection and resist the conditions encountered in a biological system. Therefore, in this study, we synthesized alginate and chitosan nanoparticles (Alg−Chi NPs) using the ionic gelation technique, which allows for the crosslinking of polymeric chains arranged in nanostructures by intermolecular interactions that can be either covalent or non-covalent. Such interactions can be achieved through the use of crosslinking agents that facilitate this binding. This technique allows for immobilization of the Ib−M1 peptide to form an Ib−M1/Alg−Chi bioconjugate. SEM, DLS, and FT-IR were used to determine the structural features of the nanoparticles. We evaluated the biological activity against E. coli ATCC 25922 and Vero mammalian cells, as well as the stability at various temperatures, pH, and proteases, of Ib−M1 and Ib−M1/Alg-Chi. The results showed agglomerates of nanoparticles with average sizes of 150 nm; an MIC of 12.5 µM, which was maintained in the bioconjugate; and cytotoxicity values close to 40%. Stability was maintained against pH and temperature; in proteases, it was only evidenced against pepsin in Ib−M1/Alg-Chi. The results are promising with respect to the use of Ib−M1 and Ib−M1/Alg−Chi as possible antimicrobial agents.

El cultivo de lima Tahití(Citrus x latifolia Tanaka ex Q. Jiménez)ocupa un importante porcentaje dentro de la cadenacomercialde los cítricos en Colombia, pero es atacado por Schizotetranychus hindustanicus o ácarohindú, un fitófago que produce lesiones típicas en el haz de las hojas y frutos, caracterizadas por manchas blanquecinas circulares que corresponden a las telarañas que teje la hembra y que le restan valor estético al fruto y a su comercialización. El objetivo del presente estudio consistió en evaluar in vitrolos efectos acaricidas de distintos compuestos en tres tiempos de contacto sobre poblaciones del ácaro.Se evaluó extracto oleaginoso de Neem (Azadirachta indica)al 1,0%, azufre micronizado al 0,5%, extracto acuoso de Azadirachtina 0,4%, filtrado de caldo de ceniza al 15 %. Como control positivo se utilizó Abamectina al 0,2%, producto reconocido por su efecto acaricida, y se usó agua destilada como control negativo. Se evidenció que los tratamientos más efectivos fueronelextracto oleaginoso de Neem-A. indicaal1,0%, azufre micronizado al 0,5%, y Abamectina al 0,2% con valores de mortalidad del 96,4;97,9 y100 % a las 72 horasrespectivamente. Los resultados permiten sugerir el uso de compuestos naturales a base de Azadirachta indicaen soluciones oleaginosas para el control deesta plaga, pues no afectan el ecosistema a la vez que no se han reportado resistencias del fitófago por su uso.