• International Journal of Industrial Entomology and Biomaterials
• /
• 제37권1호
• /
• pp.15-20
• /
• 2018

Most proteins produced in the endoplasmic reticulum (ER) of eukaryotic cells fold via disulfide formation (oxidative folding). Oxidative folding is catalyzed by protein disulfide isomerase (PDI) and PDI-related ER protein thiol disulfide oxidoreductases (ER oxidoreductases). In yeast and mammals, ER oxidoreductin-1s (ERO1s) supply oxidizing equivalent to the active centers of PDI. We previously identified and characterized the ERO1 of Bombyx mori (bERO1) as a thioredoxin-like protein that shares primary sequence homology with other ERO1s. Here we compare the reactivation of inactivated rRNase and sRNase by bERO1, and show that bERO1 and bPDI cooperatively refold denatured RNase A. This is the first result suggesting that bERO1 plays an essential role in ER quality control through the combined activities of bERO1 and bPDI as a catalyst of protein folding in the ER and sustaining cellular redox homeostasis.

• Journal of Microbiology and Biotechnology
• /
• 제19권7호
• /
• pp.685-689
• /
• 2009

We describe the expression of recombinant canstatin from stably transformed Bombyx mori BmS (BmS) cells. Recombinant canstatin was secreted into a culture medium with a molecular mass of approximately 29 kDa. Densitometric scanning showed that the secreted canstatin accounted for approximately 91% of the total canstatin production. Recombinant canstatin was also purified to homogeneity using a simple one-step Ni-NTA affinity fractionation. The identity of the purified protein was confirmed as human canstatin by nano-LC-MS/MS analysis. Purified recombinant canstatin inhibited human endothelial cell proliferation in a dose-dependent manner. The concentration at half-maximum inhibition ($ED_{50}$) for recombinant canstatin expressed in stably transformed BmS cells was approximately 0.64 ${\mu}g/ml$. A maximum production level of 11 mg/l recombinant canstatin was obtained in a T-flask culture of BmS cells after 6 days of incubation.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제15권2호
• /
• pp.131-135
• /
• 2007

Open reading frame 4 of Bombyx mori nucleopolyhedrovirus (BmNPV), designated as Bm4, is a gene whose function is completely unknown. With the recently developed BmNPV bacmid and a modified pFastBac1 whose polyhedrin promoter was replaced with ie1 promoter, a recombinant bacmid expressing Bm4-EGFP fusion protein under the control of ie1 promoter in BmN cells was successfully constructed. The result not only showed that the polyhedrin promoter can be replaced efficiently with other promoters to direct the expression of foreign gene in BmN cells by using Bac-to-Bac/BmNPV baculovirus expression system but also laid the foundation for rescue experiment of Bm4 deletion mutant due to the ability of ie1 promoter to direct gene expression throughout the infection cycle.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제17권2호
• /
• pp.173-180
• /
• 2008

The influence of temperature and relative humidity in infection and cross-infection of Nosema bombycis and N. mylitta respectively in mulberry silkworm, Bombyx mori L. on larval mortality, multiplication of pathogens, larval weight and growth rate in three different seasons were studied. Seasons were selected in such condition, when very less fluctuations between minimum and maximum temperature and minimum and maximum relative humidity ($25{\sim}28^{\circ}C$ and $65{\sim}72%$ R.H) was observed i.e., season-1. Fluctuations between minimum and maximum temperature were less ($28.05{\sim}34.50^{\circ}C$) but R.H % was more ($55{\sim}81%$) in season-2. Fluctuations between minimum and maximum temperature and R.H % were more ($20.00{\sim}40.5^{\circ}C$ and $64.00{\sim}90.00%$) in season-3. Growth rate of microsporidian-infected silkworm is directly related to the prevailing temperature and relative humidity in silkworm. Silkworm can tolerate slight variation of temperature but slight variation of relative humidity disfavours the development of silkworm and favours the multiplication of pathogens.

• Preventive Nutrition and Food Science
• /
• 제6권1호
• /
• pp.19-22
• /
• 2001

Conjugated linoleic acid (CLA) exhibits potent anti-carcinogenic and other biological activities in several animal models. We report here that dietary CLA, chemically synthesized from corn oil, accumulates I silkworm, Bombyx mori, which is used as therapeutic agent for diabetes in Korea and Japan. Mulberry leaves treated with 0.1 or 10% CLA in ethanol were supplied to silkworms from the end of 3rd instar to the 3rd day of the 5th instar. Fresh mulberry leaves or leaves treated with 10% corn oil in ethanol were fed as a check treatment. the amount of total lipids in the larval body ranged from 17.4 to 19.1mg/g of body tissue, which was not significantly affected by the source of the diets. No CLA was found in the control silkworms. But the level of CLA significantly increased to 83.5 mg/g of fat, when fed with mulberry leaves treated with 10% CLA. Only trace amounts of CLA were detected in the larvae reared with check leaves and 0.1% CLA-treated leaves. Mulberry leaves treatd with corn oil or CLA were not palatable to the larvae, resulting in a reduction of larval weight. These results suggest that silkworms containing CLA in body lipids could be producted by dietary CLA.

• 한국응용곤충학회지
• /
• 제34권3호
• /
• pp.243-248
• /
• 1995

효과적인 미생물 제제로 사용할 수 있는 Bacillus thuringiensis 균주들을 분리하기 위하여 경기도 일원의 72군데의 저곡창고에서 먼지를 채취하여 B. thuringiensis의 분포와 독성을 조사하였다. 총 411개의 채취된 저곡창고의 먼지에서 포자와 내독소 단백질을 생산하는 146개에 이르는 많은 수의 B. thuringiensis가 분리되었다. 저곡창고에서 분리된 146개 Bt의 독성 분포는 나비목의 누에 (Bombyx mori)유충에 독성을 띠는 균주가 84%로 가장 많이 분리되었고, 파리목의 빨간 집모기(Culex pipiens)유충에는 3%, 나비목과 파리목에 동시에 독성을 띠는 균주는 1%였다. 그러나 딱정벌레목의 쌀바구미(Sitophitus oryzae)에 독성을 띠는 균주는 분리되지 않았으며, 내독소 단백질은 형성하지만 독성을 띠지 않는 B. thuringiensis가 12%의 비율로 분리되어 흔히 존재함을 알 수 있었다. 이상의 결과로서 저곡창고는 B. thuringiensis의 유리한 분리장소임을 알 수 있었다.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제4권2호
• /
• pp.149-153
• /
• 2002

Induction of non-diapause eggs and manifestation of quantitative characters were studied in different seasons by low temperature incubation of eggs of a low yielding diapause with coloured cocoons silkworm breed, RDI of Bombyx mori. Hundred percent of nandiapause eggs were induced when the egg incubation was carried out at 15$^{\circ}C$ followed by incubation initially at $25^{\circ}C$ and then at $15^{\circ}C$. The diapause-nondia-pause relation was found to be reversible. Analysis of variance study demonstrated significant variation in all the quantitative characters whereas significant variation due to different incubation treatments was observed for larval span, fifth instar larval span, cocoon yield/10,000 larvae by weight, cocoon weight, cocoon shell weight, and cocoon shell ratio. study on hybrid vigour skewed significant heterosis over mid parent value for four economic characters viz., cocoon weight, cocoon shell weight, cocoon shell ratio and filament length in a Fl hybrid between RD1 with diapause eggs and Japanese type bivoltine $NB_{4} D_{2}$.

• 한국미생물·생명공학회지
• /
• 제24권1호
• /
• pp.72-76
• /
• 1996

To investigate the expression efficiency of new transfer vector of Bombyx mori nuclear polyhedrosis virus (BmNPV), Escherichia coli lacZ gene was inserted into new transfer vector pBmKSK1, under the control of polyhedrin promoter and expressed in BmN-4 cells and larvae of silkworm, Bombyx mori. The recombinant virus containing lacZ gene was isolated from BmN-4 cells coinfected with transfer vectro pBmKSK1-LacZ and wild type BmNPV genome, and analysed by Southern blotting. The expression of ${\beta}$-galactosidase was characterized by SDS-PAGE, Western blotting and ${\beta}$-galactosidase activity assay. The results showed that the level of expression in silkworm larvae was higher than that of BmN-4 cells.

• BMB Reports
• /
• 제41권5호
• /
• pp.400-403
• /
• 2008

The insect baculovirus expression vector system (BEVS) is useful for producing biologically active recombinant proteins. However, the overexpressions of foreign proteins using this system often results in misfolded proteins and the formation of protein aggregates. To overcome this limitation, we developed a versatile baculovirus expression and secretion system using Bombyx mori protein disulfide isomerase (bPDI) as a fusion partner. bPDI gene fusion was found to improve the secretions and antibacterial activities of recombinant nuecin proteins. Thus, we conclude that bPDI gene fusion is a useful addition to BEVS for the large-scale production of bioactive recombinant proteins.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제2권2호
• /
• pp.111-117
• /
• 2001

Screening of fifteen bivoltine silkworm breeds of Bombyx mori Linn at a temperature of $31{\pm}1^{\circ}C$ and relative humidity of 85${\pm}$5% resulted in the identification of eight thermo-tolerant breeds. The survival and cocoon shell ratio of the tolerant breeds ranged from 72.7 to 78.7% and 20.0 to 20.1% respectively. The tolerant breeds comprised of four oval breeds and four dumb-bell breeds. Eight foundation crosses prepared by crossing the oval and dumb-bell parents among themselves were screened at a temperature of $31{\pm}1^{\circ}C$ and relative humidity of 85{\pm}5%. The performance of the foundation crosses on 11 economic characters were analysed by employing Multipie Trait Evaluation Index method. Four foundation crosses which scored average index value > 50 were selected as breeding parents and breeding initiated for the evolution of thermo-tolerant bivoltine silkworm breeds. The methodology and the results of the foundation crosses reared both at 31{\pm}1$^{\circ}C$ and at $25{\pm}1^{\circ}C$ temperatures, are discussed.