RESUMO
Type II myosin, the primary component of the thick filament of muscle fibers, is organized as a dimeric high molecular weight protein, and is composed of a pair of heavy chains (MHC) and two pairs of light chains. Myosin II transforms ATP energy into mechanical force. All type II myosins are conserved proteins but they have two variable regions that are located in different places of the molecule. Myosin molecules are encoded by a multigene family and many isoforms are generated. The expression of myosins depends on the developmental stage and on the type and degree of contractile activity and tissue, therefore several myosin isoforms are found in the same organism. Here we describe the use of different techniques that allowed demonstrating the presence of isoforms of the heavy chain type II myosin of Taenia solium cysticerci (larvae) and tapeworms (adults), a cestode parasite of importance in public health in many developing countries. Myosin was purified and used in comparative proteolytic fragmentation, ATPase activity, detection of antigenic differences and electrophoretic separation. The results obtained showed biochemical and immunochemical differences among cysticerci and tapeworms, and demonstrate the presence of myosin isoforms in T. solium that are probably associated to physiological requirements of each developmental stage.
Assuntos
Fibras Musculares Esqueléticas/química , Músculos/química , Cadeias Pesadas de Miosina/química , Miosina Tipo II/química , Taenia solium/química , Taenia solium/crescimento & desenvolvimento , Adenosina Trifosfatases/metabolismo , Animais , Antígenos/imunologia , Epitopos/imunologia , Larva/química , Larva/crescimento & desenvolvimento , Larva/imunologia , Fibras Musculares Esqueléticas/imunologia , Músculos/imunologia , Cadeias Pesadas de Miosina/imunologia , Cadeias Pesadas de Miosina/isolamento & purificação , Miosina Tipo II/imunologia , Miosina Tipo II/isolamento & purificação , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/imunologia , Peptídeo Hidrolases/química , Isoformas de Proteínas/química , Isoformas de Proteínas/imunologia , Isoformas de Proteínas/metabolismo , Suínos , Taenia solium/imunologiaRESUMO
Identification, localization and partial biochemical characterization of actins expressed in the larval stage of the cestode parasite Taenia solium has been carried out. Frozen tissue sections of cysticerci, the larval stage of this parasite, were reacted with rhodamine-phalloidin, parasite actin was purified by polymerization in the presence of K(+), Mg(++) and ATP actin was analyzed by SDS-PAGE and two-dimensional gel electrophoresis, and immunoblotting of actin was performed in PVDF membranes and with commercial anti-actin monoclonal antibodies. Parasitic tissues showed different fibrous actin fluorescence patterns, which correlated with the expression of isoactins. Purified globular actin had a similar molecular mass to rabbit commercial actin (approximately 44 kDa). Actin was resolved into seven isoforms, indicating a family of actin genes.