Browsing by Author "URREA, R"

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    A HIGH-MOLECULAR-WEIGHT PROTEOGLYCAN IS DIFFERENTIALLY EXPRESSED DURING DEVELOPMENT OF THE MOLLUSK CONCHOLEPAS-CONCHOLEPAS (MOLLUSCA, GASTROPODA, MURICIDAE)
    (1992) BRANDAN, E; GONZALEZ, M; INESTROSA, NC; TREMBLAY, C; URREA, R
    Incorporation of radioactive sulfate to hatched veliger larvae of the gastropod muricid Concholepas concholepas indicated that over 87% of the sulfated macromolecules were found in the detergent insoluble fraction, rich in extracellular matrix (ECM) components. The sulfated material was solubilized with guanidine salt followed by urea dialysis and fractionated by DEAE-Sephacel chromatography. Three sulfated compounds eluting at 0.7, 1.1, and 3.0 M NaCl, called peaks I, II, and III, respectively, were obtained. The sulfated compound present in peak I was degraded by pronase or sodium alkaline treatment to a small sulfated resistant material, suggesting the presence of a proteoglycan (PG). Filtration analysis on Sephacryl S-500 and SDS-PAGE of the intact PG indicates that it has a high molecular weight (360,000 to over 1 X 10(6)). Monoclonal antibodies (mAb) against this PG were produced. The specificity of one mAb, the 6H2, was demonstrated by size chromatography and ELISA analysis. The epitope recognized by this mAb seems to be present in the core protein of the PG. Both the extent of sulfation and the presence of different sulfated species of PGs were evaluated during the development of this mollusc. A twelvefold increase in the incorporation of sulfate to PGs per milligram of protein was found in veliger larvae compared to blastula-glastula stages. This change correlated well with the differential expression of the sulfated PG present in peak I. Biochemical and immunological analysis indicate that high levels of this PG are found in veliger and trocophore larvae in comparison with blastula-gastrula and early juveniles. These results indicate that a high molecular weight PG probably of the ECM is differentially expressed during the development of the gastropod Concholepas concholepas.
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    EFFECT OF SALT CONCENTRATION ON THE SYNTHESIS OF SULFATED MACROMOLECULES IN THE BRINE SHRIMP (ARTEMIA-FRANCISCANA) - CHANGES OF SULFATION RATE DURING DEVELOPMENT
    (1993) BRANDAN, E; URREA, R; GAJARDO, G
    1. The effect of sodium chloride and sulphate concentrations on the rate of sulphation was evaluated in four developmental stages of the brine shrimp Artemia franciscana, a crustacean inhabiting extreme hypersaline environments.
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    ISOLATION OF PROTEOGLYCANS SYNTHESIZED BY RAT-HEART - EVIDENCE FOR THE PRESENCE OF SEVERAL DISTINCT FORMS
    (1992) GONZALEZ, R; URREA, R; GONZALEZ, M; INESTROSA, NC; BRANDAN, E
    1. The proteoglycans (Ps) synthesized by auricle and ventricle from adult rat
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    SULFATION IS REQUIRED FOR MOBILITY OF VELIGER LARVAE OF CONCHOLEPAS-CONCHOLEPAS (MOLLUSCA, GASTROPODA, MURICIDAE)
    (1992) URREA, R; GONZALEZ, M; INESTROSA, NC; BRANDAN, E
    The sulfation reaction seems to be a critical biochemical process during early steps of development. We have evaluated the effect of sulfation on the mobility of veliger larvae of the gastropod Concholepas concholepas. It was found that incubation of larvae in low-sulfate artificial sea water had strong inhibitory effect on mobility. The use of sodium chlorate, a specific inhibitor of sulfation, also resulted in a strong inhibition of larval mobility. At the biochemical level, the synthesis of proteoglycans (PGs) and detergent-soluble sulfoproteins and sulfolipids was specifically inhibited by chlorate, without affecting either total protein synthesis or phosphorylation. Intracellular levels of the sulfate donor 3'-phosphoadenosine 5'-phosphosulfate (PAPS) were decreased to 4% by chlorate treatment, indicating that this molecule is also involved in sulfation of marine invertebrates. Both effects of chlorate, the inhibition of sulfation and the larval mobility, were reversible. It is therefore concluded that sulfation is required for larval mobility in the mollusc C. concholepas.