• Title/Summary/Keyword: molecular genetics

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Expression and Biochemical Characterization of the Bacillus thuringiensis Cry4B ${\alpha}1$-${\alpha}5$ Pore-forming Fragment

  • Puntheeranurak, Theeraporn;Leetacheewa, Somphob;Katzenmeier, Gerd;Krittanai, Chartchai;Panyim, Sakol;Angsuthanasombat, Chanan
    • BMB Reports
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    • v.34 no.4
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    • pp.293-298
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    • 2001

  • Tryptic activation of the 130-kDa Bacillus thuringiensis Cry4B $\delta$-endotoxin produced protease-resistant products of ca. 47 kDa and ca. 21 kDa. The 21-kDa fragment was identified as the N-terminal five-helix bundle (${\alpha}1-{\alpha}5$,) which is a potential candidate for membrane insertion and pore formation. In this study, we constructed the recombinant clone over-expressing this putative pore-forming (PPF) fragment as inclusion bodies in Escherichia coli. The partially purified inclusions were composed of a 23-kDa protein, which cross-reacted with Cry4B antibodies, and whose N-terminus was identical to that of the 130-kDa protein. Dissimilar to protoxin inclusions, the PPF inclusions were only soluble when the carbonate buffer, pH 9.0, was supplemented with 6 M urea. After renaturation via a stepwise dialysis, the refolded PPF protein appeared to exist as an oligomer and was structurally stable upon trypsin treatment. Unlike the 130kDa protoxin, the refolded protein was able to release entrapped glucose from liposomes, and showed comparable activity to the full-length activated toxin, although it lacks larvicidal activity These results, therefore, support the notion that the PPF fragment that consists of ${\alpha}1-{\alpha}5$ of the activated Cry4B toxin is involved in membrane pore-formation.

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Expression of Heterotic Genetic Interaction among Multivoltine Recurrent Backcross/Congenic Lines for Higher Shell Weight of Silkworm, Bombyx mori L.

  • Verma, A.K.;Chattopadhyay, G.K.;Sengupta, M.;Sengupta, A.K.;Das, S.K.;Urs, S.Raje
    • International Journal of Industrial Entomology and Biomaterials
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    • v.7 no.1
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    • pp.21-27
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    • 2003

  • Manifestation of heterotic genetic interaction was studied in different hybrids made between multivoltine recurrent backcross (RBL)/congenic lines (Con. L) during unfavourable season when temperature and relative humidity are > $30^{\circ}C$ and 86%, respectively. A few number of silkworm race or strain or breed like Nistari (N ＋ p or Np) can sustain the temperature above 3$0^{\circ}C$ and RH above 86%. The present heterosis study screened a hybrid i.e., CB$_{5}$Lm5RBL1M$_{6}$DPC-LmE$^1$RBL and its reciprocal provided heterobeltiotic effect on survival by number and pupation rate at a magnitude of 20% (p < 0.01) and yield by weight of 10% (p < 0.01). Beside all the hybrids expressed heterosis over check - Nistari (N ＋ p) with better quality silk. Therefore, aforesaid hybrid may be useful for utilization at commercial level during adverse seasons of West Bengal.gal.

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