The developmental fate of immature thymocytes is determined by the specificity of their T-cell antigen receptors (TCRs). Immature CD4+8+ thymocytes are positively selected to differentiate into mature T cells by recognition of peptides associated with major histocompatibility complex (MHC) encoded molecules on thymic epithelial cells. But neither the… (More)
Precursor cells differentiate into mature CD4+ and CD8+ T cells in the inductive environment of the thymus by undergoing a series of distinct developmental steps marked by expression of the coreceptor molecules CD4 and CD8. Among the earliest cells to enter the CD4/CD8 developmental pathway are CD4-CD8lo precursors cells that differentiate into CD4+CD8+… (More)
Lineage commitment is a developmental process by which individual CD4+CD8+ (double positive, DP) thymocytes make a decision to differentiate into either CD4+ or CD8+ T cells. However, the molecular event(s) that defines lineage commitment is controversial. We have previously proposed that lineage commitment in DP thymocytes can be molecularly defined as the… (More)
As a consequence of positive selection in the thymus, immature CD4(+)8(+) double-positive, [DP] thymocytes selectively terminate synthesis of one coreceptor molecule and, as a result, differentiate into either CD4(+) or CD8(+) T cells. The decision by individual DP thymocytes to terminate synthesis of one or the other coreceptor molecule is referred to as… (More)
The understanding of the environmental preferences and life history of a species in its native range provides insights for assessing its potential success in a novel area. Hemiodus orthonops is a migratory fish from the Paraguay and Middle Paraná rivers that invaded the Upper Paraná River through a fish pass, constructed in 2002. The invasion of this fish… (More)
This study evaluated the relationship between the young of year (YOY) abundance of migratory fish species and the interannual variations in the duration and delay of floods in the Upper Paraná River floodplain. YOY of the most abundant migratory species Brycon orbignyanus, Hemisorubim platyrhynchos, Leporinus elongatus, Leporinus macrocephalus, Leporinus… (More)
Precursor cells differentiate into mature CD4 + and CD8 + T cells in the inductive environment of the thymus by undergoing a series of distinct developmental steps marked by expression of the coreceptor molecules CD4 and CD8. Among the earliest cells to enter the CD4/CD8 developmental pathway are CD4-CD8 l~ precursors cells that differentiate into CD4+CD8 +… (More)
Due to an unfortunate turn of events, the last author's surname appeared incorrectly in the original publication and should have read Espinola. The correct representation of the authors' names is listed above and should be treated as definitive by the reader.