, 1999). Activation of previously stored proteases during atresia would constitute an economical mechanism to reallocate energy stored as yolk content, which has already been observed in a mosquito (Uchida et al., 2001) and suggested in a bug (Kotaki, 2003). Additionally, a growing amount of evidence has been accumulated about the role of lysosome-released IDH signaling pathway cathepsins, e.g. cathepsin D, on triggering the apoptosis cascade in a caspase-independent fashion (Chwieralski et al., 2006), which would represent an interesting possibility in our model. Cysteine proteases are
described as lysosomal and extracellular enzymes in many models (Fagotto, 1995 and Sriraman and Richards, 2004) and have been shown to play a role as yolk-degrading proteins in other models (Takahashi et al., 1993, Takahashi et al., 1997, Yamamoto et al., 1994, Liu et TGF-beta inhibitor al., 1996 and Cho et al., 1999) but not R. prolixus ( Atella et al., 2005, Fialho et al., 2005 and Nussenzveig et al., 1992). In R. prolixus the acidification of yolk granule preparations from oocytes and developing eggs has been reported to lead to pepstatin-sensitive, leupeptin and antipain insensitive yolk proteolysis ( Nussenzveig et al., 1992 and Fialho et al., 2005). Based on these data and in our data of concurrent cysteine and aspartic protease activities in atretic follicles, we propose
that yolk degradation in R. prolixus atresia is mediated by novel synthesized cysteine proteases, since these hydrolases probably do not play a role in yolk degradation in this model ( Nussenzveig et al., 1992, Atella et al., 2005 and Fialho et al., 2005). At this point, however, a role of cysteine proteases in normal follicle cell degeneration during on the onset of choriogenesis and/or during atresia process cannot be ruled out since previous work may have overlooked it due to its minor contribution in whole oocyte homogenates. De novo synthesis of Cathepsin L on follicle atresia
has already been recorded, although only in mammalian models ( Sriraman and Richards, 2004). Together, these results show that infection leads to atresia Amino acid of the ovarian vitellogenic follicles in R. prolixus with apoptotic and autophagic death of follicle cells, allowing us to extend and complement the literature of PCD in ovarian follicles from lepidopteran, hymenopteran and dipteran models to a hemipteran ovary model. As the disturbance of hormone signaling is known to induce atresia in R prolixus, we speculate that local signaling, e.g. eicosanoid signaling, involved both in immunity and reproduction ( Medeiros et al., 2002, Medeiros et al., 2004, Stanley, 2006 and Machado et al., 2007), could be disturbed in mycosed animals. It is also tempting to reinforce the possible major role of the host-mediated fitness adjustment over pathogen-mediated manipulation during microbial challenges.