• Journal of Sericultural and Entomological Science
• /
• v.35 no.2
• /
• pp.129-133
• /
• 1993

The 44Md plasmid of Bacillus thruingiensis var. kurstaki HD-1(B. t k HD-1) was partially digested with Sau3AI and the fragments were cloned into E. coli HB101 on vector pBR322. Of 2, 950 clones with a recombinant pBR322, only one clone KC1 was determined to have the gene for crystal toxic proteins from the 44Md plasmid of B. t k HD-1 at the BamHI site of pBR322. The recombinant pBR322 was named pKC1 and its molecular size was 12kb. The KC1 produced a protein which was toxic to the silkworm and antigenically similar to the crystal toxic protein of B. t k HD-1. Also, electrophoretic mobility of the KC1 protein was apparently the same as that of the crystal toxic protein of B. t k HD-1.

• Korean journal of applied entomology
• /
• v.48 no.2
• /
• pp.253-261
• /
• 2009

For the environment-friendly control of beet armyworm, Spodoptera exigua, in spring onion fields, we have examined an alternative application method. Twenty-five insecticides registered for spring onion were tested for control effect against the beet armyworm in the laboratory, then the best 9 chemical and a single biological insecticides were selected and compared with 2 new isolates of Bacillus thuringiensis in a polyvinyl house. After that, 4 chemical and 3 B. thuringiensis treatments were used in the field for the control of beet armyworm in the spring onion. Two application methods are used: one is triple treatments with the same chemical and the other is alternative application with different chemicals and B. thuringiensis for 7 days intervals. Indoxacarb WP - chlorfluazuron EC - B.t. var. kurstaki CAB141 and indoxacarb WP - methoxyfenozide + spinosad SC - Chlorfluazuron EC - B.t. var. aizawai CAB109, B.t. var. kurstaki CAB141 showed greater than 78% mortality of beet armyworm larvae and greater than 43% damage decrease in spring onions infested by beet armyworm. These results showed that alternative applications had higher control effect than any other applications. It was suggested that alternative applications with microbial biological agents such as B. thuringiensis might minimize the development of insecticide resistance and might be used as the environment-friendly control of the beet armyworm.

• The Microorganisms and Industry
• /
• v.16 no.1
• /
• pp.18-20
• /
• 1990

현재 전세계적으로 10,000여개 이상의 실험실에서 생물공학적인 연구가 진행중에 있고, 200여개 이상의 회사에서 생물공학을 이용한 제품이 만들어지고 있다.(Saftlas, 1984). 이와같은 제품으로 생물농약(예, 모기억제에 사용되는 Bacillus thuringiensis var. israelensis 등)이라든가 insulin, 성장호르몬, lymphotoxin및 항암제등의 의약품(Saftlas, 1984)과 식물품종개량제(예, 질소 공정의 vector로 사용되는 Agrobacterium tumerfaciens의 Ti Plasmid)(McDanial, 1981 ; Shaw, 1986) 등이 있다. 그러나 최근 미생물 생태분야에서는 이와같이 만들어진 미생물들 (genetically engineered microorganisms : GEMs)이 자연 생태계에 유출되었을때 야기될 가능성이 있는 biohazaed에 대하여 관심이 집중되고 있다. (Curtiss, 1976 ; Sharples, 1983 ; Rissler, 1984). 토양환경에서 GEM이 유전물질을 전달항 수 있는 기작은 크게 conjugation, transduction, transformation 등이 알려지고 있다. 여기서는 주로 토양환경에서 transformation에 의한 유전물질의 전달과정에 대한 최근 연구동향을 간단히 기술하고자 한다.

• The Korean Journal of Pesticide Science
• /
• v.17 no.1
• /
• pp.27-32
• /
• 2013

Damage of tea bagworms, Eumeta minuscula was observed for the first time from grape leaves of grape (varieties: Cambell Early and M.B.A.) from a vinery at Gumho-up, Gyeongsan, Gyeongbuk on 31 August, 2012. Activity of insecticides [Bacillus thuringiensis var. kurstaki (serotype IIIa, IIIb) WP, chlorantraniliprole 5% GP, methoxyfenozide 21% SC, spinetoram 5% GP, and spinosad 10% GP] was tested on fourth instar larvae of Eumeta minuscula in laboratory. Mortality of 4th instar of Eumeta minuscula was higher when treated with spinosad 10% WG (88.7%) and spinetoram 5% WG (67.7%) sprayed with field recommended concentration using a home sprayer in laboratory. Mortality decreased as the concentration decreased, however leaf damage rate was significantly different between the one-fourth rate and the control. Spinetoram 5% WG and spinosad 10% WG showed 63.7 and 55.7% respectively mortality of fourth instar Eumeta minuscula in field. Though these two insecticides could be used for the control of bagworms on grape, a more effective insecticide needs to be found.

• Microbiology and Biotechnology Letters
• /
• v.32 no.2
• /
• pp.110-116
• /
• 2004

The over-expression in E. coli of the pHLN1-SO(＋) and pHLN2-80(－) plasmids cloned an insecticidal crystal protein (ICP) gene (crylAal type) from Bacillus thuringiensis var. kurstaki HD 1 was investigated through in part, the deletion of -80 bp promoter and an alternative change of cloning vector system. Two recombinant plasmids were constructed in an attempt to analyze the over-expression of the ICP in relations to its gene structure possessing only -14 bp ［Shine-Dalgarno (SD) sequence of -80 bp promoter］. Also, anther two recombinant plasmids similarly cloned the icp gene in a different vector system. The amounts of ICP produced from the recombinants were measured by SDS-PAGE and confirmed by Western blot analysis. One clone, pHLRBS1-14 clone in which only the SD sequence in the inverted orientation icp gene appeared, was more evident than the pHLRBS2-14 clone in which only the -14 bp SD sequence of the right orientated icp gene was shown to exist. The pHLN2-80(－) clone produced more ICP proteins than the pHLRBS1-14 clone. In the two clones, pHLNUC1-80 right-oriented icp gene and the pHLNUC2-80 clone inverted-orientation icp gene in a new different vector, the pHLNUC2-80 produced more ICP proteins in E. coli system. These results indicate that the P/ac promoter, the inverted icp gene insertion and -80 bp promoter (-66 bp part of the icp gene promoters), were concerned with the expression of the icp gene in the recombinant plasmids. In addition, the expression mechanism might result from the disruption of the transcription-suppressing regions in the promoter regions.

• Microbiology and Biotechnology Letters
• /
• v.26 no.6
• /
• pp.497-506
• /
• 1998

The expression in Escherichia coli of a cloned insecticidal protein (ICP) gene from Bacillus thuringiensis var. kurstaki HD1 in pHLN1-80 (+) and pHLN2-80(-) plasmids was investigated through deletions in promoters, transcription start point, and termination region. Six recombinant plasmids were constructed in an attempt to analyze the overexpression of the ICP in relations to its gene structure. The amounts of ICP produced from the recombinants were measured by SDS-PAGE and confirmed by Western blot analysis. One clone was not overexpressed which having only -80 bp (contained BtI promoter) part of the ICP gene promoter (without Plac promoter), the right-oriented ICP gene and the termination region. Removal of 350 bp from upstream region of the Plac of the clone pHLN2-80 (-) resulted in overexpression of the ICP. One clone was not overexpressed in which the clone consisted of -72 bp part of the ICP promoter without the transcription start point and the transcriptional termination region, and having the right-oriented ICP gene sequence. One clone consisting of the inverted ICP gene sequence, the -72 bp ICP gene promoter, and without the termination region caused overexpression. One clone which consisted of the inverted ICP gene, the -72 bp ICP gene promoter and the termination sequence was overexpressed. These results indicated that the Plac promoter, transcription termination region, the inverted ICP gene insertion, and the -80 bp or -72 bp part of the ICP gene promoters were concerned in the overexpression of the ICP gene in the recombinant plasmid, and also the overexpression mechanism might result from the disruption of the transcription-suppressing regions in the promoter regions.

• Applied Biological Chemistry
• /
• v.19 no.4
• /
• pp.189-201
• /
• 1976

In an effort to develop a microbial in secticide, B. thdringiensis var. thuringiensis was cultured in the medium composed of cocoon-cooked water from a filature. The results obtained are summarized as followss : (1) Bacillus thuringiensis is a bacterium producing a ${\delta}-endotoxin$ especially toxic to lepidopterous insects and a thermostable exotoxin harmful to dipterous insects. (2) With a view to utilizing the cocoon-cooked water discarded from the filature, as a nutrient source in the B. thuingiensis culture, it was analyzed to contain large amounts of various minerals and protein (7.5 mg/ml) believed to be extracted from the pupae. (3) A large amount of the ${\delta}-endotoxin$ can be obtained most cheeply by using cocoon-cooked water instead of distilled water in preparing GYS and citrate salts media. (4) The largest amount of a mixture of the vegetative cells, spores, and crystals was obtained by addition of 8 gr/l of glucose to the GYS medium. (5) The growth of the bacterium was far better, when leucine, isoleucine, and valine were added all together to the citrate salts medium to the concentration of $1.25{\times}10^{-3}M$. (6) The best growth was observed by addition of Na-glutamate to the citrate salts medium to the concentration of $2.5{\times}10^{-3}M$. (7) The optimal culture time ranged from 9 to 15 days. (8) The highest mortality was shown in Pieris rapae Linne with a pH of the total body extract of 8.4, whereas Dendrolimus spectabilis Butler and Bombyx mori Linne with lower pH's were less susceptible to the ${\delta}-endotoxin$. (9) The presence of the thermo stable exotoxin was confirmed by the fact that the supernatant of the culture was very toxic to the Drosophila melanogaster tested.

• Korean Journal of Environmental Biology
• /
• v.38 no.1
• /
• pp.189-196
• /
• 2020

Mosquitos serve as vectors for diseases, causing inconvenience as well as a threat to human life and health. Concern about mosquitos introducing and spreading new diseases has been intensifying. We observed a variety of mosquito habitats based on land cover classification from Korea's Ministry of Environment, and the mosquito species that could appear were classified according to the each habitat type. Finally, we suggested the best control methods for each type of habitat considering habitat characteristics and the ecological traits of mosquitos. Urban areas harbor various habitats for pests, contributing significantly to mosquito habitats. Control must be performed regarding larva and adults because various sources for habitats exist. Public mosquito control programs such as educational training, as well as information brochures can be effective in managing mosquito populations and public health. Agricultural areas show high densities of mosquito larva to lentic zones such as reservoirs, wetlands, paddy fields. So, biological control using natural predators may be effective in controlling mosquito populations. Forests are major habitats for Aedes albopctus, so physical controls should be deployed for residents living nearby, and excessive deforestation should be minimized. Other areas including aquatic ecosystems should be adopted regarding biological control using Bti (Bacillus thuringiensis var. israelensis) and chemical control for eradicating mosquitos. We classified habitats into four types of land cover patterns considering ecological traits and habitat preference, and suggest adequate control methods for each habitat type. Our suggestion can be used to positively contribute toward effective managing mosquito's density and reducing the damage to public health.