Besnoitia besnoiti and Toxoplasma gondii: two apicomplexan strategies to manipulate the host cell centrosome and Golgi apparatus

Besnoitia besnoiti and Toxoplasma gondii are two closely related parasites that interact with the host cell microtubule cytoskeleton during host cell invasion. Here we studied the relationship between the ability of these parasites to invade and to recruit the host cell centrosome and the Golgi apparatus. We observed that T. gondii recruits the host cell centrosome towards the parasitophorous vacuole (PV), whereas B. besnoiti does not. Notably, both parasites recruit the host Golgi apparatus to the PV but its organization is affected in different ways. We also investigated the impact of depleting and over-expressing the host centrosomal protein TBCCD1, involved in centrosome positioning and Golgi apparatus integrity, on the ability of these parasites to invade and replicate. Toxoplasma gondii replication rate decreases in cells over-expressing TBCCD1 but not in TBCCD1-depleted cells; while for B. besnoiti no differences were found. However, B. besnoiti promotes a reorganization of the Golgi ribbon previously fragmented by TBCCD1 depletion. These results suggest that successful establishment of PVs in the host cell requires modulation of the Golgi apparatus which probably involves modifications in microtubule cytoskeleton organization and dynamics. These differences in how T. gondii and B. besnoiti interact with their host cells may indicate different evolutionary paths.

Órgãos de governo da família empresária Governing bodies of family business

RESUMO A importância das empresas familiares nas economias modernas exige que sejam melhor conhecidos os processos de tomada de decisão nas mesmas, nomeadamente, aqueles que têm origem no seio das famílias que as detêm ou controlam. A separação do património da família e do património afecto ao negócio é uma condição necessária para um bom relacionamento entre estes dois subsistemas. À semelhança dos órgãos de administração da empresa familiar também a família empresária tem os seus órgãos de governo: reunião de família, assembleia de família, conselho familiar, comissões familiares ad-hoc, protocolo familiar e family office. São estes órgãos que vão ser apresentados. ABSTRACT The importance that family firms have in today’s economy requires that one understands the decision making process in these types of firms, particularly the decision making process that stem from within the family circle that controls the firm. In order to understand these processes and the relationship between the two “subsystems of decision-making” one must separate the family’s resources from the family’s resources that has been engaged in the business. The family businesses, likewise the family firm, also have its own bodies of administration, such as family assemblies, family councils, family commissions and meetings, family’ protocols, as well as family office.