Mapping the caribbean scientific collaboration.: Can mobility of researchers help?

International audienceCaribbean communities were mobile long before European colonization and their modes of production and culture were evolving by frequent exchanges among the Caribbean islanders and the Northern coast of South America. However, the region has not fully benefited by the advent of the five Technological Revolutions since 1771. Moreover, in the last two decades of the XX century, the Caribbean Small Islands Developing States (SIDS) were severely affected by the migration of their tertiary educated population towards the developed world, a trend that continues today.Bibliometric approaches have been used to identify not only the brain drain, but also how the contemporary knowledge is created through the international network of scientific collaboration. In this study we use the Scopus bibliographic database to analyse the scientific output and international collaboration of the 13 Caribbean SIDS in the period between 2000 and 2018. The main scientific collaborator of the region as a country is United States, except for Cuba, which is Spain. Consequently, North America, Europe and the Caribbean islands share the higher proportion of co-authoring articles. In terms of institutional representation, the University of West Indies has, in aggregate, the highest output with 11,497 documents from 11 out of 13 SIDS. The main contributor as a country is Jamaica (5018), followed by Trinidad and Tobago. A group of high output academic institutions are University of Havana (4979), followed by Universidad Central de Las Villas, Institute of Tropical Medicine Pedro Kouri and the Centre of Genetic Engineering and Biotechnology, all of them in Cuba and with no significant collaboration with the rest of the region.In previous bibliometric studies we found that the scientists working abroad has the potential to become agents for development of the home country and region, diversifying the scientific collaboration

Molecular basis for the differential use of glucose and glutamine in cell proliferation as revealed by synchronized HeLa cells

During cell division, the activation of glycolysis is tightly regulated by the action of two ubiquitin ligases, anaphase-promoting complex/cyclosome–Cdh1 (APC/C-Cdh1) and SKP1/CUL-1/F-box protein–β-transducin repeat-containing protein (SCF-β-TrCP), which control the transient appearance and metabolic activity of the glycolysis-promoting enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase, isoform 3 (PFKFB3). We now demonstrate that the breakdown of PFKFB3 during S phase occurs specifically via a distinct residue (S273) within the conserved recognition site for SCF-β-TrCP. Glutaminase 1 (GLS1), the first enzyme in glutaminolysis, is also targeted for destruction by APC/C-Cdh1 and, like PFKFB3, accumulates after the activity of this ubiquitin ligase decreases in mid-to-late G1. However, our results show that GLS1 differs from PFKFB3 in that its recognition by APC/C-Cdh1 requires the presence of both a Lys-Glu-Asn box (KEN box) and a destruction box (D box) rather than a KEN box alone. Furthermore, GLS1 is not a substrate for SCF-β-TrCP and is not degraded until cells progress from S to G2/M. The presence of PFKFB3 and GLS1 coincides with increases in generation of lactate and in utilization of glutamine, respectively. The contrasting posttranslational regulation of PFKFB3 and GLS1, which we have verified by studies of ubiquitination and protein stability, suggests the different roles of glucose and glutamine at distinct stages in the cell cycle. Indeed, experiments in which synchronized cells were deprived of either of these substrates show that both glucose and glutamine are required for progression through the restriction point in mid-to-late G1, whereas glutamine is the only substrate essential for the progression through S phase into cell division

Anaphase-promoting complex/cyclosome-Cdh1 coordinates glycolysis and glutaminolysis with transition to S phase in human T lymphocytes

Cell proliferation is accompanied by an increase in the utilization of glucose and glutamine. The proliferative response is dependent on a decrease in the activity of the ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C)-Cdh1 which controls G1-to-S-phase transition by targeting degradation motifs, notably the KEN box. This occurs not only in cell cycle proteins but also in the glycolysis-promoting enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoform 3 (PFKFB3), as we have recently demonstrated in cells in culture. We now show that APC/C-Cdh1 controls the proliferative response of human T lymphocytes. Moreover, we have found that glutaminase 1 is a substrate for this ubiquitin ligase and appears at the same time as PFKFB3 in proliferating T lymphocytes. Glutaminase 1 is the first enzyme in glutaminolysis, which converts glutamine to lactate, yielding intermediates for cell proliferation. Thus APC/C-Cdh1 is responsible for the provision not only of glucose but also of glutamine and, as such, accounts for the critical step that links the cell cycle with the metabolic substrates essential for its progression