Bacillus thuringiensis como controlador biológico de Brevicoryne brassicae en el cultivo de col (Brassica oleracea var. Capitata)

Bacillus are a well-known genus of bacteria that are characterized by others by the great resistance they present against acids, high temperatures, high pressure, bases and long storage times. B. thuringiensis is a bacterium that is located in soils located and characteristically produce protein crystals that exhibit insecticidal activity; these crystals are formed in the sporulation stage and are composed of toxins from the Cry and/or Cyt families, which once ingested by insects, these toxins are activated proteolytically. Research has determined that a single plasmid of B. thuringiensis is possible to host multiple variants of cry and cyt that in their combination determine the specificity of the host insect. Ingestion: In this step unlike other insecticides, this one must be ingested; because the proteins of B. thuringiensis act only before the previous ingestion of the insect and never through contact. Solubilization: This phase consists of the breakage of the crystals and the release of the proteins present in them. This phase is mainly produced by trypsins and chymotrypsins, the most abundant enzymes in the insect's intestinal fluids. Crossing the intestinal membrane: Once the toxins are activated, the peritrophic membrane of the intestine reduces the amount of toxins that can interact with intestinal cells, having an effect on the insect's final susceptibility to the toxin, which are capable of degrading chitin. This manages to generate an osmotic imbalance that is capable of leading to cell rupture. Through the lysis of the intestinal cell sepsis occurs, caused by all opportunistic bacteria and other pathogens in the food bolus, which produces the death of the insect

Bacillus are a well-known genus of bacteria that are characterized by others by the great resistance they present against acids, high temperatures, high pressure, bases and long storage times. B. thuringiensis is a bacterium that is located in soils located and characteristically produce protein crystals that exhibit insecticidal activity; these crystals are formed in the sporulation stage and are composed of toxins from the Cry and/or Cyt families, which once ingested by insects, these toxins are activated proteolytically. Research has determined that a single plasmid of B. thuringiensis is possible to host multiple variants of cry and cyt that in their combination determine the specificity of the host insect. Ingestion: In this step unlike other insecticides, this one must be ingested; because the proteins of B. thuringiensis act only before the previous ingestion of the insect and never through contact. Solubilization: This phase consists of the breakage of the crystals and the release of the proteins present in them. This phase is mainly produced by trypsins and chymotrypsins, the most abundant enzymes in the insect's intestinal fluids. Crossing the intestinal membrane: Once the toxins are activated, the peritrophic membrane of the intestine reduces the amount of toxins that can interact with intestinal cells, having an effect on the insect's final susceptibility to the toxin, which are capable of degrading chitin. This manages to generate an osmotic imbalance that is capable of leading to cell rupture. Through the lysis of the intestinal cell sepsis occurs, caused by all opportunistic bacteria and other pathogens in the food bolus, which produces the death of the insect

Bacillus son un conocido género de bacterias que se caracterizan con otras por la gran resistencia que presentan frente a los ácidos, altas temperaturas, alta presión, bases y largos tiempos de almacenamiento. El B. thuringiensis es una bacteria que se localiza en los suelos ubica y característicamente producen cristales proteicos que exhiben actividad insecticida; estos cristales se forman en la etapa de esporulación y se encuentran compuestas por toxinas de las familias Cry y/o Cyt, que una vez que son ingeridas por los insectos, dichas toxinas se activan proteolíticamente. Investigaciones han determinado que un solo plásmido de B. thuringiensis es posible de albergar múltiples variantes de cry y cyt que en su combinación determinan la especificidad del insecto huésped. Ingestión: En este paso a diferencia de otros insecticidas, éste debe ser ingerido; debido que las proteínas del B. thuringiensis actúan únicamente ante la previa ingestión del insecto y nunca a través del contacto. Solubilización: Esta fase consiste en la rotura de los cristales y la liberación de las proteínas presentes en ellas. Esta fase es producida principalmente por tripsinas y quimotripsinas, las enzimas más abundantes en los fluidos intestinales del insecto. Atravesar la membrana intestinal: Una vez activada las toxinas la membrana peritrófica del intestino reduce la cantidad de toxinas que pueden llegar a interactuar con las células intestinales, teniendo un efecto sobre la susceptibilidad final del insecto a la toxina, que son capaces de degradar la quitina. Esta logra generar un desequilibrio osmótico que es capaz de desembocar en la rotura celular. A través de la lisis de la célula intestinal se produce una septicemia, ocasionan por todas las bacterias oportunistas y otros patógenos en el bolo alimenticio, lo que produce la muerte del insecto