Detection and quantification of a very high density lipoprotein in different tissues of Triatoma infestans during the last nymphal and adult stages.

The presence of a very high density lipoprotein (VHDL), an hexameric protein, was explored in different tissues of Triatoma infestans throughout the last nymphal and adult stages, and in egg extracts by Western blot assays. The VHDL was always detected in both, hemolymph and fat body, during the above mentioned stages and it was also observed in the buffer soluble fraction of testis and egg homogenates. An enzyme-linked immunosorbent assay (ELISA) was used to measure the VHDL titer in these tissues. Hemolymph VHDL reaches a maximum value before the last molt, then it abruptly declines in males and females just after emergence, but during adult life it increases again. Fat body VHDL decreases slowly and continuously during the nymph growth reaching a minimum value prior to molting, and in the first week of adult life the values were even two-fold lower; then, it shows a different cycle of accumulation and depletion in males and females. In adult testis the VHDL undergoes a cycle similar to the one observed in male fat body. This protein increases progressively during embryonic development and, at the time of larval hatching it reaches its maximum value. The hexameric protein presents homologies in its N-terminal sequence with storage hexamerins of Diptera, Lepidoptera and Hymenoptera.