Trayectoria reciente y perspectivas futuras de la industria naval pesada argentina : Los astilleros estatales

Con un marco regulatorio de tipo proteccionista que buscaba promover la construcción de barcos en el país, la industria naval argentina se consolidó y expandió hasta los años 80 gracias a una fuerte intervención estatal, iniciada durante el proceso de Industrialización por Sustitución de Importaciones (isi). El presente trabajo se propone describir la historia reciente de este sector industrial, desde 1950 hasta la actualidad, centrando la atención en dos aspectos fundamentales: por un lado, el rol central del Estado (y de su política industrial) como regulador, productor, cliente y agente de financiación de la industria naval; por otro, la activa participación de los actores sociales, especialmente los trabajadores organizados, en la supervivencia productiva del sector en la década del 90. Para llevar adelante este propósito, nos centramos en el estudio de los dos astilleros estatales de construcción y reparación naval más importantes del país: Astillero Río Santiago (ars) y Talleres Dársena Norte (Tandanor). A modo de conclusión, reflexionamos sobre los principales desafíos y la perspectiva futura del sector así como sobre las responsabilidades que, en tal sentido, les caben a los actores sociales más relevantes

DNA alignment and Bayesian trees of partial sequences of COI, COIII and the haemocyanin functional unit f-g of 28 octopod species

Background: Octopods have successfully colonised the world's oceans from the tropics to the poles. Yet, successful persistence in these habitats has required adaptations of their advanced physiological apparatus to compensate impaired oxygen supply. Their oxygen transporter haemocyanin plays a major role in cold tolerance and accordingly has undergone functional modifications to sustain oxygen release at sub-zero temperatures. However, it remains unknown how molecular properties evolved to explain the observed functional adaptations. We thus aimed to assess whether natural selection affected molecular and structural properties of haemocyanin that explains temperature adaptation in octopods. Results: Analysis of 239 partial sequences of the haemocyanin functional units (FU) f and g of 28 octopod species of polar, temperate, subtropical and tropical origin revealed natural selection was acting primarily on charge properties of surface residues. Polar octopods contained haemocyanins with higher net surface charge due to decreased glutamic acid content and higher numbers of basic amino acids. Within the analysed partial sequences, positive selection was present at site 2545, positioned between the active copper binding centre and the FU g surface. At this site, methionine was the dominant amino acid in polar octopods and leucine was dominant in tropical octopods. Sites directly involved in oxygen binding or quaternary interactions were highly conserved within the analysed sequence. Conclusions: This study has provided the first insight into molecular and structural mechanisms that have enabled octopods to sustain oxygen supply from polar to tropical conditions. Our findings imply modulation of oxygen binding via charge-charge interaction at the protein surface, which stabilize quaternary interactions among functional units to reduce detrimental effects of high pH on venous oxygen release. Of the observed partial haemocyanin sequence, residue 2545 formed a close link between the FU g surface and the active centre, suggesting a role as allosteric binding site. The prevalence of methionine at this site in polar octopods, implies regulation of oxygen affinity via increased sensitivity to allosteric metal binding. High sequence conservation of sites directly involved in oxygen binding indicates that functional modifications of octopod haemocyanin rather occur via more subtle mechanisms, as observed in this study.