The dispersed gene family 1 ( DGF-1 ) is the fifth largest gene family in the T rypanosoma cruzi genome, with over 500 members (11). Many of the predicted DGF-1 protein products have several transmembrane domains and N - glycosylation and phosphorylation sites and were thought to localize in the plasma membrane. Here, we report that affinity-purified antibodies against a region of one of these proteins (DGF-1.2) localized it intracellularly in different stages of the parasite. DGF-1.2 is more abundant in the amastigote stage than in trypomastigotes and epimastigotes, as detected by immunofluorescence and Western blot analyses. The protein changed localization during intracellular or extracellular differentiation from the trypomastigote to the amastigote stage, where it finally localized to small bodies in close contact with the inner side of the amastigote plasma membrane. DGF-1.2 did not colocalize with markers of other subcellular organelles, such as acidocalcisomes, glycosomes, reservosomes, lipid droplets, or endocytic vesicles. During extracellular differentiation, the protein was detected in the culture medium from 0 to 22 h, peaking at 14 h. The presence of DGF-1.2 in the differentiation culture medium was confirmed by mass spectrometry analysis. Finally, when epimastigotes were subjected to starvation, there was a decrease in the labeling of the cells and, in Western blots, the appearance of bands of lower molecular mass, suggesting its cleavage. These results represent the first report of direct immunodetection and developmental expression and secretion of a DGF-1 protein.

Objectives: Scorpion envenomation is a common public health problem in Venezuela. We report an envenoming case by Tityus breweri, endemic to the Guayana Shield, southeast Venezuela, and the outcome of its treatment with antivenom anti– Tityus discrepans. Toxin composition and antigenic reactivity of T breweri venom were also explored. T breweri distribution range was re-evaluated. Methods: Clinical signs and symptoms in an adult male were recorded after envenoming and treatment with antivenom. Toxin composition and antigenicity of T breweri venom were investigated by polyacrylamide gel electrophoresis, immunoblotting, and mass spectrometry. T breweri distribution range was reassessed by mapping new records of the species. Results: The moderately severe case (a 21-year-old man) presented autonomic manifestations, including cardiopulmonary and gastrointestinal effects. Full recovery was achieved after anti– T discrepans antivenom administration. T breweri venom contains toxins in the 6–8 kd range that affect voltage-sensitive sodium channels. Based on new records, T breweri distribution area reaches 12 155 km. ² Inclusion of southeast Venezuela as an endemic area of scorpionism prompted the examination of clinical, immunological, and phylogenetic evidence for suggesting a partitioning of the Venezuelan Tityus fauna into toxinological provinces. Conclusions: The severity of the case reinforces categorization of the Guayana Shield region as a macroendemic area of scorpionism in Venezuela and allows classification of T breweri as a species of medical importance, with toxins immunologically related to central-eastern Venezuelan Tityus. Partitioning of the territory incorporating multiple criteria may help health authorities establish and implement preventive and therapeutic measures for scorpion envenoming in this region.