• Korean Journal of Plant Tissue Culture
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• v.24 no.5
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• pp.305-311
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• 1997

Bacillus thuringiensis, a gram-positive soil bacterium, is characterized by its ability to produce crystalline inclusions during sporulation. The crystal proteins exhibit a highly specific insecticidal activity. An insecticidal crystal protein (ICP), Cry II A, is specifically toxic to both lepidopteran and dipteran insects. In this study, tobacco plants transformed by the cry II A gene have been generated. The Cry II A crystal protein was purified from E. coli JM103 harboring cry II A gene by differential solubility. The activated Cry II A was prepared by tryptic digestion. The purified protoxin (70 kDa) and the activated toxin (50 kDa) were analyzed by SDS-PAGE. To generate the transgenic tobacco having cry II A gene, the cry II A gene was subcloned to a plant expression vector, pSRL2, having two CaMV 35S promoters. The recombinant plasmid was transformed into tobacco (N. tabacum var. Petit Havana SR1) by Agrobacterium-mediated leaf disc transformation. Through the regeneration, six putative transgenic tobacco plants were obtained and three transformants were confirmed by Southern blot analysis. It has been found that one plant had single copy of cry II A gene, another had two copies of the gene, and the third had a truncated gene. After the immunochemical confirmation of cry II A expression in plants, the transgenic tobacco plants will be used to study the genetics of future generation with the insecticidal crystal protein gene cry II A.

• BMB Reports
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• v.40 no.5
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• pp.783-790
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• 2007

Receptor binding plays an important role in determining host specificity of the Bacillus thuringiensis Cry $\delta$-endotoxins. Mutations in domains II and III have suggested the participation of certain residues in receptor recognition and insect specificity. In the present study, we expressed the cloned domain II-III fragment of Cry4Ba and examined its binding characteristics to mosquito-larval midgut proteins. The 43-kDa Cry4Ba-domain II-III protein over-expressed in Escherichia coli as inclusion bodies was only soluble when carbonate buffer, pH 10.0 was supplemented with 4M urea. After renaturation via stepwise dialysis and subsequent purification, the refolded domain II-III protein, which specifically reacts with anti Cry4Ba-domain III monoclonal antibody, predominantly exists as a $\beta$-sheet structure determined by circular dichroism spectroscopy. In vitro binding analysis to both histological midgut tissue sections and brush border membrane proteins prepared from susceptible Aedes aegypti mosquito-larvae revealed that the isolated Cry4Ba-domain II-III protein showed binding functionality comparable to the 65-kDa full-length active toxin. Altogether, the data present the 43-kDa Cry4Ba fragment comprising domains II and III that was produced in isolation was able to retain its receptor-binding characteristics to the target larval midgut proteins.

• International Journal of Industrial Entomology and Biomaterials
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• v.19 no.1
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• pp.199-204
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• 2009

The newly cloned Bacillus thuringiensis cry1-5 gene showed high activity to both Plutella xylostella and Spodoptera exigua, while cry1Ac only showed high activity against P. xylostella but low to S. exigua. Through the alignment of amino acid sequences between Cry1Ac and Cry1-5, we found 12 different residues in domain I (6 residues) and domain II (6 residues). In this study, the modified cry1Ac gene, which is constructed according to a crop-preferring codon usage, was used as a template to construct mutant B. thuringiensis cry1Ac genes based on cry1-5 gene through multi site-directed mutagenesis. Total 63 various mutant cry genes were obtained at 12 positions randomly. Among them, ten mutant cry genes, whose domain I was totally converted and domain II was randomly, were selected to express in baculovirus expression system as a polyhedrin fusion form. The recombinant proteins were 95 kDa in size and were stably activated as 65 kDa by trypsin. The expressed mutant Cry proteins were applied to bioassays against P. xylostella and S. exigua. All mutants showed high insecticidal activity both to P. xylostella and S. exigua similar to cry1-5. These results suggest that these mutant cry genes might be expected of desirable cry genes for introduction to transgenic crops.

• Korean journal of applied entomology
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• v.36 no.4
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• pp.341-350
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• 1997

We have now constructed a novel recombinant baculovirus producing fusion protein with Autographa californica nuclear polyhedrosis virus (AcNPV) polyhedrin and Bacillus thuringiensis(Bt) cryIA(c) crystal protein. The fusion protein expressed by the recombinant baculovirus in insect cells was characterized. The N-terminal of cryIA(c) gene of Bt subsp. kurstaki HD-73 was introduced under the control of polyhedrin gene promoter of AcNPV, by fusion in the front of intact polyhedrin gene or by insertion into the HindIII site in polyhedrin gene. The recombinant baculoviruses were named as BtrusI or BtrusII, respectively. Although single transcript from the fusion protein gene was apparently observed. BtrusI was produced the two proteins, 92 kDa fusion protein and only polyhedrin. In addition, fusion protein produced by BtrusI did not form polyhedra. Interestingly, however, the cells infected with BtrusII did not show a 33 kDa polyhedrin band as a cells infected with BtrusI. Cells infected with BtrusII were only produced fusion protein, but the polyhedra formed by fusion protein was not observed. To determine the insecticidal toxicity of fusion protein, therefore, Sf9 cells infected with BtrusI were inoculated to Bombyx mori larvae. Sf9 cells infected with BtrusI that expressed the fusion protein caused larval mortality although the insecticidal toxicity was low. In conclusion, our results clearly demonstrated that the fusion protein with polyhedrin and Bt cryIA(c) crystal protein have a insecticida toxicity.

• Plant Biotechnology Reports
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• v.4 no.4
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• pp.293-301
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• 2010

The feasibility of two strategies for transgene pyramiding using Agrobacterium-mediated transformation was investigated to develop a transgenic potato (Solanum tuberosum L. cv. Iwa) with resistance to potato tuber moth (PTM) (Phthorimaea operculella (Zeller)). In the first approach, cry1Ac9 and cry9Aa2 genes were introduced simultaneously using a kanamycin (nptII) selectable marker gene. The second approach involved the sequential introduction (re-transformation) of a cry1Ac9 gene, using a hygromycin resistance (hpt) selectable marker gene, into an existing line transgenic for a cry9Aa2 gene and a kanamycin resistance (nptII) selectable marker gene. Multiplex polymerase chain reaction (PCR) confirmed the presence of the specific selectable marker gene and both cry genes in all regenerated lines. The relative steady-state level of the cry gene transcripts in leaves was quantified in all regenerated lines by real-time PCR analysis. Re-transformation proved to be a flexible approach to effectively pyramid genes for PTM resistance in potato, since it allowed the second gene to be added to a line that was previously identified as having a high level of resistance. Larval growth of PTM was significantly inhibited on excised greenhouse-grown leaves in all transgenic lines, although no lines expressing both cry genes exhibited any greater resistance to PTM larvae over that previously observed for the individual genes. It is anticipated that these lines will permit more durable resistance by delaying the opportunities for PTM adaptation to the individual cry genes.

• Journal of Sericultural and Entomological Science
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• v.38 no.2
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• pp.154-159
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• 1996

To isolate Bacillus thuringiensis toxic to Spodoptera species, we collected soil samples in Korea. In these samples, we characterized 7 B. thuringiensis isolates toxic to spodoptera exigua or S. litura from soil, granary and sericultural farm samples. The 7 isolates were named B. thuringiensis STB-1, STB-2, STB-3, STB-4, STB-5, STB-6 and STB-7, respectively. The bioassay of these isolates against S. exigua and S. litura showed highly insecticidal activity. The serotypes of them were determined by agglutination tests using 33 antisera ; STB-1 an STB-2 are identical to B. thuringiensis subsp. kurastaki, and STB-3, STB-4 and STB-5 are identical to subsp. kenyae. STB-6 and STB-7 did not react with 33 antisera. STB-1 and STB-3 which have different gene types from B. thuringiensis subsp. kurastaki and subsp. kenyae are identified new isolates. STB-6 and STB-7 which show no agglutination in serological tests havd cryIA(a), cryIA(b), cryIC, and cryII genes are also identified new isolates. Molecular weights of parasporal inclusions of all isolates were determined approximately 130 kDa by SDS-polyacrylamide gel elctrophoresis.

• Journal of Microbiology and Biotechnology
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• v.23 no.8
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• pp.1107-1115
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• 2013

The Cyt1Aa protein of Bacillus thuringiensis susbp. israelensis elaborates demonstrable toxicity to mosquito larvae, but more importantly, it enhances the larvicidal activity of this species Cry proteins (Cry11Aa, Cry4Aa, and Cry4Ba) and delays the phenotypic expression of resistance to these that has evolved in Culex quinquefasciatus. It is also known that Cyt1Aa, which is highly lipophilic, synergizes Cry11Aa by functioning as a surrogate membrane-bound receptor for the latter protein. Little is known, however, about whether Cyt1Aa can interact similarly with other Cry proteins not primarily mosquitocidal; for example, Cry2Aa, which is active against lepidopteran larvae, but essentially inactive or has very low toxicity to mosquito larvae. Here we demonstrate by ligand binding and enzyme-linked immunosorbent assays that Cyt1Aa and Cry2Aa form intermolecular complexes in vitro, and in addition show that Cyt1Aa facilitates binding of Cry2Aa throughout the midgut of C. quinquefasciatus larvae. As Cry2Aa and Cry11Aa share structural similarity in domain II, the interaction between Cyt1Aa and Cry2Aa could be a result of a similar mechanism previously proposed for Cry11Aa and Cyt1Aa. Finally, despite the observed interaction between Cry2Aa and Cyt1Aa, only a 2-fold enhancement in toxicity resulted against C. quinquefasciatus. Regardless, our results suggest that Cry2Aa could be a useful component of mosquitocidal endotoxin complements being developed for recombinant strains of B. thuringiensis subsp. israelensis and B. sphaericus aimed at improving the efficacy of commercial products and avoiding resistance.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5725-5728
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• 2012

Growing evidence shows that deregulation of the circadian clock plays an important role in the development of malignant tumors, including gliomas. However, the molecular mechanisms of gene chnages controlling circadian rhythm in glioma cells have not been explored. Using real time polymerase chain reaction and immunohistochemistry techniques, we examined the expression of two important clock genes, cry1 and cry2, in 69 gliomas. In this study, out of 69 gliomas, 38 were cry1-positive, and 51 were cry2-positive. The expression levels of cry1 and cry2 in glioma cells were significantly different from the surrounding non-glioma cells (P<0.01). The difference in the expression rate of cry1 and cry 2 in high-grade (grade III and IV) and low-grade (grade 1 and II) gliomas was non-significant (P>0.05) but there was a difference in the intensity of immunoactivity for cry 2 between high-grade gliomas and low-grade gliomas (r=-0.384, P=0.021). In this study, we found that the expression of cry1 and cry2 in glioma cells was much lower than in the surrounding non-glioma cells. Therefore, we suggest that disturbances in cry1 and cry2 expression may result in the disruption of the control of normal circadian rhythm, thus benefiting the survival of glioma cells. Differential expression of circadian clock genes in glioma and non-glioma cells may provide a molecular basis for the chemotherapy of gliomas.

• BMB Reports
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• v.37 no.3
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• pp.304-313
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• 2004

Three-dimensional (3D) models for the 65-kDa activated Cry4A and Cry4B $\delta$-endotoxins from Bacillus thuringiensis subsp. israelensis that are specifically toxic to mosquito-larvae were constructed by homology modeling, based on atomic coordinates of the Cry1Aa and Cry3Aa crystal structures. They were structurally similar to the known structures, both derived 3D models displayed a three-domain organization: the N-terminal domain (I) is a seven-helix bundle, while the middle and C-terminal domains are primarily comprise of anti-parallel $\beta$-sheets. Circular dichroism spectroscopy confirmed the secondary structural contents of the two homology-based Cry4 structures. A structural analysis of both Cry4 models revealed the following: (a) Residues Arg-235 and Arg-203 are located in the interhelical 5/6 loop within the domain I of Cry4A and Cry4B, respectively. Both are solvent exposed. This suggests that they are susceptible to tryptic cleavage. (b) The unique disulphide bond, together with a proline-rich region within the long loop connecting ${\alpha}4$ and ${\alpha}5$ of Cry4A, were identified. This implies their functional significance for membrane insertion. (c) Significant structural differences between both models were found within domain II that may reflect their different activity spectra. Structural insights from this molecular modeling study would therefore increase our understanding of the mechanic aspects of these two closely related mosquito-larvicidal proteins.

• Journal of Dental Anesthesia and Pain Medicine
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• v.19 no.1
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• pp.29-36
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• 2019

Background: An inability to cope with threatening dental stimuli, i.e., sight, sound, and sensation of airotor, manifests as anxiety and behavioral management problems. Behavior modification techniques involving pre-exposure to dental equipment will give children a first-hand experience of their use, sounds, and clinical effects. The aim of this study was to compare the techniques of Tell-Show-Play-doh, a smartphone dentist game, and a conventional Tell-Show-Do method in the behavior modification of anxious children in the dental operatory. Methods: Sixty children in the age group of 4-8 years, with Frankl's behavior rating score of 2 or 3, requiring Class I and II cavity restorations were divided into three groups. The groups were Group 1: Tell-Show-Play-doh; Group 2: smartphone dentist game; and Group 3: Tell-Show-Do technique and each group comprised of 20 children. Pulse rate, Facial Image Scale (FIS), Frankl's behavior rating scale, and FLACC (Face, Leg, Activity, Cry, Consolability) behavior scales were used to quantify anxious behavior. Operator compliance was recorded through a validated questionnaire. Results: The results showed lower mean pulse rates, lower FIS and FLACC scores, higher percentage of children with Frankl's behavior rating score of 4, and better operator compliance in both the Tell-Show-Play-doh and smartphone dentist game groups than in the conventional Tell-Show-Do group. Conclusion: The Tell-Show-Play-doh and smartphone dentist game techniques are effective tools to reduce dental anxiety in pediatric patients.