Expression of theHelicoverpa cathepsin b-like proteinase during embryonic development

Abstract

Cathepsin B-like proteinase from Helicoverpa armigera (HCB) was proposed as being involved in the degradation of yolk proteins during embryonic development. Recombinant HCB was expressed as a fusion protein with GST in Escherichia coli BL21 on the basis of its cDNA and purified to homogeneity. The fusion protein was cleaved with thrombin to generate a soluble protease with a mass of 37 kDa. A polyclonal antiserum against this recombinant protein, raised in the rabbit, recognized three isoforms of HCB in an ovary homogenate of this insect. Expression of this enzyme during embryonic development was studied using immunoblotting, immunohistochemistry and activity assay. It was found that HCB was expressed during embryonic development and that its proteolytic activity was detected from embryonic developmental eggs. The fact that HCB activity is observed in ovaries and developing eggs suggested that the enzyme had already been activated before embryonic development. Immunohistochemistry indicated that the enzyme was located in follicular cells, the sphere of yolk granules, and the fat bodies of female adult. These lines of evidence suggested strongly that HCB takes part in the degradation of yolk proteins during the development of embryo.

20-hydroxyecdysone activates Forkhead box O to promote proteolysis during Helicoverpa armigera molting

“…The paraffin sections were cut into 7 μm slices, placed on gelatin-coated slides, and dried overnight at 42°C. The slides were treated following previously described methods (Zhao et al, 2005). The sections were digested with proteinase K (50 µg/ml) for 30 min at room temperature and incubated overnight at 4°C with specific antibodies [1:200 in 2% bovine serum albumin (BSA)] after being blocked for 30 min in 2% BSA at 37°C.…”

Embryonic diapause highlighted by differential expression of mRNAs for ecdysteroidogenesis, transcription and lipid sparing in the cricketAllonemobius socius

“…The majority of genes involved in inter-conversion of cellular energy reserves are downregulated in pre-diapause embryos. Cathpesin B participates in the digestion of yolk proteins in a number of insects (Medina et al, 1988;Ribolla and De Mianchi, 1995;Cho et al, 1999;Zhao et al, 2005). Downregulation of this gene in A. socius (25% in pre-diapause) could slow digestion of the yolk proteins during a time when it is critical to preserve the fuel stores that will be required to complete postdiapause development.…”

The Steroid Hormone 20-Hydroxyecdysone Promotes the Cytoplasmic Localization of Yorkie to Suppress Cell Proliferation and Induce Apoptosis

“…The cotton bollworms were fed with an artificial diet composed of wheat and soybean (32). The cotton bollworms were obtained from Henan Agricultural University (Zhengzhou, China).…”