, 1999 and Khila and Abouheif, 2008). In the course of embryonic development, the vitellin GSI-IX supplier peptides undergo specific cleavages inside the oocyte resulting in new smaller peptides. These cleavages occur due proteases associated with the yolk granules, that may be synthesized inside the oocyte or extraovarially, and activated during the embryonic development ( Giorgi et al., 1999). The lack of immunoreactivity of the vg2 antibody against the 36 kDa fragment may be due to low immunogenicity of this protein portion or because there is a small fraction of antibodies in the polyclonal serum raised against
the 156 kDa protein that bind to the 36 kDa fragment. In A. mellifera workers, the 180 kDa full-length vitellogenin is cleaved in two distinct fragments in the fat body, being one small N-terminal of 40 kDa and one large C-terminal of 150 kDa, and the antibodies produced
against the 180 kDa vitellogenin fail in recognize the 40 kDa fragment this website ( Havukainen et al., 2011). The 36 kDa protein of E. tuberculatum queen eggs was also used as an immunogen, but the antibody obtained was unsatisfactory. The small proteins present in the queen egg extracts that reacted unspecifically with the vg1 and vg2 antibodies may be artefacts of the extraction process. About some other proteins present in the haemolymph of E. tuberculatum, the 195 kDa and 80 kDa may be lipophorin and hexamerin subunits, respectively, like described for some ants ( Martínez Urease et al., 2000, Wheeler and Buck, 1995 and Wheeler and Martínez, 1995). The lipophorins are important for lipid transport, while the hexamerins may have functions in nutrient storage, hormone carriers, immune protection and cuticle formation ( Burmester, 1999). The 120 kDa protein found in the haemolymph of E. tuberculatum workers with 2 and 5 days of age may be a hexamerin remaining from the pupal stages that is depleted from the haemolymph during the first days of adult lifespan, likely found for a 110 kDa hexamerin in other ants ( Wheeler and Buck, 1995). Our results indicate that the production of vitellogenin in E. tuberculatum is related
to the age of the workers and the ovarian cycle described by Fénéron and Billen (1996). Our data showed that vitellogenin appears in the haemolymph of workers around the fifth day after emergence, being secreted in quantities not detectable by SDS-PAGE. The age at which the ovaries of workers of E. tuberculatum begin to be activated is variable, since at the end of the first week after adult emergence workers can be found that either have ovarioles without follicles and only undifferentiated cells or ovarioles with oocytes in the early accumulation of vitellogenin ( Fénéron and Billen, 1996). Vitellogenin production remains low until the second week after emergence. At the 20th day it is present in large amounts in the haemolymph, at which time the workers have developing oocytes ( Fénéron and Billen, 1996).