RESUMO
The protein fraction of the German cockroach, Blattella germanica (L.), tergal gland secretion was examined. SDS-PAGE separation of proteins present in B. germanica tergal gland secretion revealed a tergal gland-secreted protein, BGTG-1, at approximately 63 kDa. BGTG-1 first appeared in tergal gland secretion at 2 days postimaginal moult and the amount of protein observed increased through day 5. A 2051 bp cDNA sequence, bgtg-1, was obtained by RACE polymerase chain reaction and contains a 1494 bp ORF encoding a predicted protein of 498 amino acids. In a Northern hybridization experiment using total RNA from B. germanica tergal gland tissue, a (32)P-labelled bgtg-1 probe hybridized to an RNA approximately 2000 bp and confirmed the 2051 bp cDNA size obtained by RACE PCR. Using the BLASTx sequence similarity search tool, the top match to the bgtg-1 ORF was found to be an alpha-amylase from Drosophila kikkawai (e-value = 1 x 10(-178)). Alignment of the bgtg-1 deduced protein sequence with alpha-amylases from fruit fly, Drosophila melanogaster, honey bee, Apis mellifera (L.) and yellow mealworm, Tenebrio molitor (L.), revealed conserved residues throughout the ORF and sequence identities ranging from 58.4 to 58.2%. Using a gel-based assay, degradation of starch by native BGTG-1 was demonstrated in vitro and we propose that BGTG-1 may be involved in processing phagostimulatory sugars present in B. germanica tergal gland secretion.
Assuntos
Blattellidae/enzimologia , alfa-Amilases/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Blattellidae/genética , Northern Blotting , Biologia Computacional , Sequência Conservada/genética , Primers do DNA , DNA Complementar/genética , Eletroforese em Gel de Poliacrilamida , Dados de Sequência Molecular , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
Male German cockroaches possess secretory glands that secrete fluid into a pair of transverse depressions on the seventh and eighth abdominal tergites. We investigated the effects of altered juvenoid titer during the first part of the last instar on tergal gland secretory tissue development and the production of tergal gland secretion proteins. Male fifth (last) instar nymphs (1-3 days post-emergent) were topically treated with the JH analog pyriproxyfen. Light and transmission electron microscopy demonstrated that treatment with pyriproxyfen produced a visible decrease in the amount of tergal gland tissue present, a deformation of the overall shape of the gland located on tergite seven, and a less orderly arrangement of the secretory cells in the tissue. The protein fraction of tergal gland secretion was examined in pyriproxyfen-treated and control insects 1, 5, and 15 days after the insects molted to the adult stage. Amounts of all tergal secretion proteins were reduced in treated insects.
