Physiological and biochemical aspects of vitellogenesis and follicular regression in vectors of Chagas' disease

LEYRIA J; AGUIRRE S; FRUTTERO L; RUBIOLO E; CANAVOSO L

Huerta Grande, Córdoba, Argentina

Jornada; XVII Jornadas Científicas de la Sociedad de Biología de Córdoba; 2009

Sociedad de Biología de Córdoba

In the hematophagous insects, reproduction is strongly associated with the nutritional status of females. To ensure an oviposition cycle, these species need a physiological compromise between the process of vitellogenesis and follicular regression. In Chagas`disease vectors, these events have been scarcely explored. Therefore, we have analyzed the main biochemical changes occurring during the progress of vitellogenesis (post-blood feeding) and follicular regression (days 15 and 30 post-vitellogenesis) in Dipetalogaster maxima, a vector of Chagas`disease. The study included: (a) measurement of vitellogenin (Vg) and vitellin (Vt) in hemolymph and ovary; (b) activity of acid phosphatase (PA), total catepsins and cathepsin D in ovary; (c) lipids (LT) y carbohydrates (CH) in ovarian tissues. Results showed that transition to follicular regression was characterized by a significant decrease of circulating Vg and its storage in ovary. During early regression, there was a gradual activation of PA and cathepsin D, an aspartic protease involved in Vt degradation. In advanced regression, stores of LT and CH were very small. These findings evidenced that ovarian tissue adjusted its metabolic status along the regression period. Its exploration will be useful to improve our understanding of biology of reproduction of Chagas`disease vectors and to define strategies for their control.