ABSTRACT
The prophenoloxidase activating system plays a major role in the defense mechanism of arthropods. In the present study, the phenoloxidase activity and its location in the hemolymph of the spiny lobster Panulirus argus is presented. Phenoloxidase activity was observed in the hemocyte lysate supernatant (HLS) and plasma after their incubation with trypsin. Higher amounts of trypsin were required to activate the HLS prophenoloxidase, due to the presence of a trypsin inhibitor in this fraction. Activation of prophenoloxidase was found when HLS was incubated with calcium, with an optimal pH between 7.5 and 8. This spontaneous activity is due to the prophenoloxidase activating enzyme, a serine proteinase that activates the prophenoloxidase once calcium ions were available. SDS was able to induce phenoloxidase activity in plasma and hemocyte fractions. Prophenoloxidase from HLS occurs as an aggregate of 300kDa. Electrophoretic studies combining SDS-PAGE and native PAGE indicate that different proteins produced the phenoloxidase activity found in HLS and plasma. Thus, as in most crustaceans, Panulirus argus contains a prophenoloxidase activating system in its hemocyte, comprising at least the prophenoloxidase activating enzyme and the prophenoloxidase. Finally, it is suggested that phenoloxidase activity found in plasma is produced by hemocyanin.
Subject(s)
Monophenol Monooxygenase/metabolism , Palinuridae/enzymology , Animals , Enzyme Inhibitors/pharmacology , Enzyme Precursors/antagonists & inhibitors , Enzyme Precursors/metabolism , Hemocytes/enzymology , Monophenol Monooxygenase/blood , Serine Endopeptidases/drug effects , Serine Endopeptidases/isolation & purification , Serine Endopeptidases/metabolism , Time Factors , Trypsin/metabolismABSTRACT
Las sales de calcio y magnesio son utilizadas como suplementos nutricionales obtenidas a partir de fuentes naturales dentro de las cuales se encuentra la dolomita, la cual es un mineral formado por un complejo doble de carbonato de calcio y magnesio. En la formulación de suplementos nutricionales a partir de la dolomita y en la búsqueda de una mayor biodisponibilidad, se obtuvo una materia prima en forma de citrato de calcio y magnesio a partir de la dolomita, la cual fue utilizada para la fabricación de las tabletas masticables de Acimín. El objetivo de nuestro estudio se centró en la evaluación toxicológica preclínica de estas tabletas, para lo cual se realizó un ensayo de toxicidad aguda oral en ratas Wistar de ambos sexos administrando la dosis de 2000 mg/kg, un ensayo de irritación de mucosa oral a dosis repetidas en hámsters Sirios Dorados hembras y un ensayo de irritacion de mucosa gástrica en ratas istar machos (250 - 300 g), aplicando las dosis de 2000, 1000 y 500 mg/kg. Como resultado se obtuvo que las tabletas de Acimín no poseen toxicidad significativa en el ensayo de toxicidad aguda oral (DL50>2000 mg/kg), no son irritantes de la mucosa oral (índice de irritacion de 0) y producen acidez e irritación sobre la mucosa gástrica a la dosis de 2000 mg/kg (AU)
