title: Current Triton X-100 treatments do not allow a complete plasminogen activator extraction from developing nervous tissue.
abstract: Determinations of plasminogen activator (PA) activity are usually performed in Triton X-100-treated tissue homogenates or crude membrane fractions. Such preparations usually involve a single Triton X-100 treatment. In the present paper we describe the pattern of variability of PA activity measured in different fractions obtained from the developing chick CNS by a repetitive procedure of Triton X-100 treatment and ultracentrifugation. To further characterize this PA activity we have also performed zymographic analyses during the embryonic development and the early postnatal life. Our results show that: a) a single Triton X-100 treatment does not completely extract the enzyme and this lead to an underestimation of the total PA activity; b) the PA activity is associated with the particulate component of the total tissue homogenate requiring its complete solubilization more drastic Triton X-100 treatments; c) better estimations of total and specific activities are obtained by using soluble fractions derived by ultracentrifugation from Triton X-100-treated membrane fractions; d) the developing chick optic lobe expresses only one kind of PA molecule along the entire development; e) the level of PA activity vary characteristically during the ontogeny and the early postnatal life indicating the existence of a developmentally regulated mechanism of PA expression.
authors.affiliation: Institute of Cell Biology and Neurosciences Prof. Eduardo De Robertis, School of Medicine, University of Buenos Aires, Paraguay, Argentina.
authors.forename: S
authors.initials: S
authors.lastname: Pereyra-Alfonso
authors.forename: G
authors.initials: G
authors.lastname: Scicolone
authors.forename: S
authors.initials: S
authors.lastname: Fiszer de Plazas
authors.forename: J P
authors.initials: JP
authors.lastname: Saavedra
authors.forename: V
authors.initials: V
authors.lastname: Flores
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D002642:Chick Embryo; D002645:Chickens; D005314:Embryonic and Fetal Development; D005342:Fibrinolysis; D015971:Gene Expression Regulation, Enzymologic; D017830:Octoxynol; D010960:Plasminogen Activators / Q000096:biosynthesis / Q000302:isolation & purification* / Q000378:metabolism; D003336:Tectum Mesencephali / Q000196:embryology / Q000201:enzymology* / Q000254:growth & development; D014461:Ultracentrifugation / Q000379:methods
chemical_list: D017830:Octoxynol; D010960:Plasminogen Activators