Characterization of digestive protease activity in the bluefin tuna Thunnus thynnus (Linnaeus, 1758)

The digestive proteases of bluefin tuna Thunnus thynnus (Linnaeus, 1758) were studied. Protease activity in stomach extracts showed two optima, at pH 2.0 and 3.5. Optimum activity for intestinal proteases was found at pH 10.0 and 12.0. Protease activity in stomach extracts was found to be stable at several pH, except for pH 12.0. Alkaline protease activity of intestine extracts was highly sensitive to acidic pH. Optimal temperatures found were 50 ºC for acid proteases and 60 ºC for alkaline proteases. The use of specific protease inhibitors indicated that the main presence of acid proteases was in stomach extracts, and serine proteases in intestine extracts. Active fractions in extracts were identified with SDS-PAGE.Se estudió la actividad proteasa digestiva de Thunnus thynnus (Linnaeus, 1758). Se encontraron dos óptimos de pH, tanto para la actividad proteasa ácida de los extractos estomacales (2,0 y 3,5) como para la actividad proteasa alcalina de los intestinales (10,0 y 12,0). La primera se mantuvo muy estable en un rango amplio de pH, a excepción de pH muy alcalinos (12,0). Por su parte, la actividad proteasa alcalina se vio afectada por pH muy ácidos. Los óptimos de temperatura se determinaron en 50 y 60 ºC para la actividad proteasa ácida y alcalina, respectivamente. Mediante el uso de inhibidores de proteasa se comprobó la presencia de proteasas aspárticas en los extractos estomacales y de serin-proteasas en los intestinales. La realización de zimogramas permitió identificar las distintas fracciones con actividad proteolítica presentes en cada extracto.Instituto Español de Oceanografí

Social Control in Transnational Families: Somali Women and Dignity in Johannesburg

Transnational mobility often separates families and distances individuals from the kinship and social structures by which they organized their lives prior to migration. Myriad forms of insecurity have been the impetus for Somali movement into the diaspora, with people fleeing the realities of conflict that have marked Somalia for decades while physically dividing families as individuals settle in different countries around the world. Mobility has altered the dynamics of households, families, and communities post-migration, reshaping social constructions as individuals move on without the familial support that sustained them in Somalia. While outcomes of these hardships are variable and often uneven in different settlement spaces, migration can offer new opportunities for people to pursue avenues from which they were previously excluded, such as by assuming roles and responsibilities their relatives once filled. These changes precipitate shifting identities and are challenging for women who find themselves self-reliant in the diaspora, particularly in the absence of (supportive) husbands and close kin.Drawing on ethnographic research in Johannesburg’s Somali community, this chapter explores the assumption that migration provides an opening for women to challenge subordinating gender norms. Settlement often grants women greater freedom to make choices in their lives, such as in employment and personal relationships, and yet they remain constrained by networks that limit their autonomy. Even with transnational migration and protracted separation, women are family representatives who must uphold cultural notions of respectability despite realities that position them as guardians and family providers. Women remain under the watchful eye of their extended families through expansive networks and the ease of modern communication, which facilitate a new form of social control as women’s behavior is carefully monitored and reported to relatives afar. These actualities raise questions about the degree to which transnational movement is a liberating force for women or rather a reconfiguration of social control. I argue that despite women’s changing position in their households and families, they remain limited by social control within their extended families and communities