Using proteomics Chan et al. (2009) observed that honey bee larvae responded to infection with Paenibacillus larvae by depleting their energy stores and producing proteins to directly combat the bacteria. In this case the infected
larvae showed a significant reduction of hexamerins, lipid carriers, retinoid- and fatty-acid binding proteins and apolipophorin III. The honey bee larvae also showed significant reduction of hex 70b and vg transcripts when up-regulation of immune-related transcripts was triggered by fungal infection ( Aronstein et al., 2010). These results, along with our findings imply that the bees face infection by diverting their energy stores towards immunity. The authors want to thank Érica Donato Tanaka for helpful discussions, Luiz Roberto Aguiar and Marcela Bezerra Laure for technical assistance, and two anonymous reviewers Apoptosis inhibitor for CAL 101 comments that improved the manuscript. This work was financed by grants from Fundação do Amparo à Pesquisa do Estado de São Paulo (FAPESP, grants 03/07041-2 and 05/03926-5).
“There are several mechanisms by which the contents of the secretory vesicles are freed in the midgut lumen. In holocrine secretion, secretory vesicles are stored in the cytoplasm until they are released, at which time the whole secretory cell is lost to the extracellular space. During exocytic secretion, secretory vesicles fuse with the midgut cell apical membrane emptying their contents without any loss of cytoplasm. In contrast, apocrine secretion involves Vorinostat mouse the loss of at least 10% of the apical cytoplasm following the
release of secretory vesicles. These have previously undergone fusions originating larger vesicles that after release eventually free their contents by solubilization. When the loss of cytoplasm is very small, the secretory mechanism is called microapocrine. Microapocrine secretion consists in releasing budding double-membrane vesicles or, at least in lepidopteran midguts, pinched-off vesicles that may contain a single or several secretory vesicles. In both cases the secretory vesicle contents are released by membrane fusion and/or by membrane solubilization caused by high pH contents or by luminal detergents (Terra and Ferreira, 2012). Exocytic, apocrine, and microaprocrine secretory mechanisms depend largely on midgut regions. Digestive enzymes are usually secreted by exocytosis in the posterior midgut, whereas alternate mechanisms like apocrine and microapocrine secretion may be observed in anterior midgut. Thus, trypsin is secreted by the posterior midgut of adult mosquitoes (Graf et al., 1986), larval flies (Jordão et al., 1996), and caterpillars (Jordão et al., 1999) by exocytosis, as well as, β-glycosidase by Tenebrio molitor middle midguts ( Ferreira et al., 2002). Trypsin is secreted by the anterior midgut of caterpillars using a microapocrine route ( Santos et al., 1986 and Jordão et al., 1999), whereas in the anterior midgut of T.