• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.173-177
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• 1996

Bacillus thuringiensis subsp. morrisoni PG-14 is a gram-positive soil bacterium producing mosquitocidal parasporal inclusions composed of several crystal proteins. Among these crystal protein genes, cryIVD gene is one of major component which has 72 kDa in size. However, these parasporal inclusions sink quickly from the surface of water where mosquito larval feeding occurred. To develope mosquitocidal cyanobacterium, therefore, we constructed the expression vector, pCYASK 5-1 harboring cryIVD gene. The expression vector, pCYASK5-1 was transformed into the cyanobacterium Syne- chocystis PCC6803 reported as a natural mosquito larval food source and the transformants were selected with kanamycin. Expression of IVD gene in transformant was characterized by SDS-polyacrylamide gel electrophoresis (PAGE) and immunoblot analysis. The mosquitocidal activity of a transformant was determined with Culex tritaeniorhynchus. The results showed that, the transformed cyanobacterium is toxic to mosquito larvae and will be expected as a potential agent that is used for mosquito control.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.230-234
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• 2002

To describe characteristics of a hemolysin in mosquitocidal Bacillus thuringiensis subsp. gyangiensis strain 21-2, Escherichia coli HB101 was transformed with a gene encoding hemolysin in the strain 21-2. Transformant 47 con-tained 2.5 kb DNA was selected by ELISA, immunoblot and DNA electrophoresis. Transformant 47-5 was recon-structed after digestion of the 2.5 kb DNA with Hind m. Transformant 47-5 contained 1.8 kb DNA and expressed 23 kDa Protein which had mosquitocidal activity to Aedes aegypti. The 23 kDa Protein itself in vitro didn't show hemolytic activity on human erythrocytes, but the protein had the activity after proteinase K treatment.

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.326-330
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• 1996

To illustrate whether a hemolysin in $\delta$-endotoxins of Bacillus thuringiensis strain 73E10-2 and subsp. israelensis had immunological identity, a cyt gene of the strain 73E10-2 which encodes a hemolysin was cloned to B. subtilis (transformant 2753). The transformant 2753 containing cyt gene produced the hemolysin which lysed sheep erythrocytes after treatment of proteinase K. The hemolysin was proved also to be toxic against mosquito larvae (Aedes aegypti). The molecular weight of the hemolysin produced from the transformant 2753 was determined to be about 25 kDa by SDS-PAGE and immunoblot. The hemolysin in $\delta$-endotoxin of subsp. israelensis and subsp. kyushensis did not react on immunoblot using polyclonal anti-$\delta$-endotoxin of the strain 73E10-2, but 70-140 kDa mosquitocidal toxins in $\delta$-endotoxin of subsp. kyushuensis reacted.

• Microbiology and Biotechnology Letters
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• v.27 no.5
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• pp.359-363
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• 1999

To prevent appearance of resistant mosquitoes against $\delta$-endotoxin of bacillus thuringiensis subsp. israelensis (Bti) in field, a mosquitocidal Bacillus thuringiensis strain 21-2(Bt21-2) producing a new type of $\delta$-endotoxin was isolated. The strain Bt 21-2 belongs to H serotype 43, B. thuringiensis subsp. guiyangiensis (Btg). The $\delta$-endotoxins from the strain Bt 21-2 and the strain Bti were a cuboid shape morphologically, but the $\delta$-endotoxin of the strain Bt 21-2 was composed of 150, 90 and 70kDa proteins on SDS-PAGE, and the antigenicity of $\delta$-endotoxin of the strain Bt 21-2 was different from that of the strain Bti on immunoblot. The $\delta$-endotoxin gene of the strain Bt 21-2 was not amplified with specific primers of $\delta$-endotoxin gene (cry4A and cry4B) of the strain Bti on PCR.

• Microbiology and Biotechnology Letters
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• v.21 no.5
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• pp.393-398
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• 1993

One strain of mosquitocidal Bacillus thuringiensis, H9B, was isolated from soil. The biochemical characteristics and flagella antigenicity of the strain H9B is similar to that of B. thuringiensis subsp. darmstadiensis. The delta-endotoxin of the strain H9B coincided with that of B. thuringiensis subsp. darmstadiensis strain 73E10-2 on agarose double immunodiffusion test. The delta-endotoxin of B. thuringiensis subsp. israelensis contains hemolysin fragment (28 kb) on SDS-PAGE when the delta-endotoxin was solubilized in alkali, while that of the strain H9B does not contain 28 kb protein.

• Microbiology and Biotechnology Letters
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• v.23 no.4
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• pp.390-396
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• 1995

Bacillus sphaericus 1593 is a larvicidal toxin-producing mosquitocidal bacterium. The toxin contains a parasporal crystalline inclusion which is composed of a protein that is activated under alkaline condition. To enhance alkaline environment around toxin protein, cryptic plasmid cured, B. sphaericus 1593 was transformed by the Bacillus pasteurii urease gene which generate ammonia from urea. Transformant produced urease at about 80% more than wild type strain. B. sphaericus 1593, and the urease gene was stably maintained. It also produced crystalline toxin protein at the same level as the wild type strain B. sphaericus 1593.

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.389-392
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• 1988

A clone pSL 2-1, which is a recombinant plasmid believed to contain the mosquitocidal crystal-line protein gene of the Bacillus sphaericus 1593, was expressed in Escherichia coli JM83 and the product of the clone was purified and identified. The unsolubilized mosquitocidal crystal proteins from the B. sphaericus had formed 43, 58, 64, 100, 113, and 130 Kd bands in the SDS-polyacrylamide gel, but the NaOH-solublized proteins at pH 12 formed 2 protein bands of 43- and 64Kd in the gel because the larger protein (precursor) bands were cleaved. The products of the pSL 2-1 clone was purified by Sephadex G-200 and only the fractions having lethal activity to the 3rd in-star larvae of mosquito Culex pipiens were analyzed by the gel. The only single protein band of 42 Kd toxic to the larvae was formed. The major toxic protein being produced from the B. sphaericus 1593 and the pSL 2-1 clone was found to be the 42 Kd.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.303-307
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• 1991

The hemolyic polypeptide in delta-endotoxin from Bacillus thun'ngiensis subsp. darmstadiensis 73ElO-2 was purified by Sephadex G-IOO gel filtration and DEAE-cellulose ion exchange column chromatography. The purity of hemolysin was confirmed by ouchterlony test and SDS-PAGE. The molecular weight of the purified hemolysin was approximately 64 KDa by SDS-PAGE. The purified hemolysin has not mosquitocidal activity against larvae of Aedes agypti, but hemolytic activity on red blood cells of rat. There is no serological relationship between delta-endotoxin from B. thuringiensis subsp. israelensis and the purified hemolysin from the . strain 73ElO-2.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.88-91
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• 2013

The Cyt1Aa protein of Bacillus thuringiensis subsp. israelensis is known to synergize mosquitocidal proteins of B. thuringiensis and Bacillus sphaericus strains. Cyt1Aa is highly lipophilic, and after binding in vivo to the midgut microvillar membrane serves as a "receptor" for mosquitocidal Cry proteins, which subsequently form cation channels that kill mosquito larvae. Here we report that Cyt1Aa can serve a similar function for lepidopteran-specific Cry proteins of B. thuringiensis in certain mosquito larvae. Engineering Cyt1Aa into the HD-1 isolate of B. thuringiensis subsp. kurstaki enhanced toxicity against $4^{th}$ instars of Aedes aegypti, but not against $4^{th}$ instars of Culex quinquefasciatus.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.40-46
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• 1998

For a biological control on a plant pathogen, Pryicularia Oryzae, and a mosquito, Aedes aegypti, Bacillus thuringiensis strain AF6 which produces parasporal inclusion, delta-endotoxin, was isolated. The B. thuringiensis strain AF6 was produced not only an antifungal substance(AFS) against P. oryzae, but also a mosquitocidal delta-endotoxin. The AFS of the strain AF6 in more stable at pH 4.0 than pH 10.0. At the mode of action, the AFS of the strain AF6 was inhibited hypha growth on potato agar plate(pH 5.0), and degraded cell walls of P. oryzae.