• Journal of Microbiology
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• v.45 no.6
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• pp.553-557
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• 2007

In order to detect and identify the most toxic Bacillus thuringiensis strains against pests, we isolated a B. thuringiensis strain (Bn1) from Balaninus nucum (Coleoptera: Curculionidae), the most damaging hazelnut pest. Bn1 was characterized via morphological, biochemical, and molecular techniques. The isolate was serotyped, and the results showed that Bn1 was the B. thuringiensis serovar, kurstaki (H3abc). The scanning electron microscopy indicated that Bn1 has crystals with cubic and bipyramidal shapes. The Polymerase Chain Reactions (PCRs) revealed the presence of the cry1 and cry2 genes. The presence of Cry1 and Cry2 proteins in the Bn1 isolate was confirmed via SDS-PAGE, at approximately 130 kDa and 65 kDa, respectively. The bioassays conducted to determine the insecticidal activity of the Bn1 isolate were conducted with four distinct insects, using spore-crystal mixtures. We noted that Bn1 has higher toxicity as compared with the standard B. thuringiensis subsp. kurstaki (HD-1). The highest observed mortality was 90% against Malacosoma neustria and Lymantria dispar larvae. Our results show that the B. thuringiensis isolate (Bn1) may prove valuable as a significant microbial control agent against lepidopteran pests.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1106-1110
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• 2001

The parasporal biogenesis of crystal inclusion during the sporulation of Bacillus sphaericus strain 1593 was observed using transmission electron microscopy. The crystal biogenesis and sporulation process involved a sequence of events talking about 10 h. The sporulation Precesses were found to be similar to previous findings. The crystal biogenesis of B. sphaericus was initiated at the start of engulfment and nearly completed by the time of exosporium formation. The crystal formation was clearly associated with the outer forespore membrane from stages III through VI, and the crystals grew from polypeptide-like chains originated from the outer forespore membrane. These observations are different from previous findings, which report no association with the forespore membrane. The crystals were located adjacent to the outer membrane of the spore until the release stage. The axes size of the bipyramidal crystal was approximately $0.25{\mu}m{\times}42{\mu}m$. During crystal biogenesis, the crystal development could be classified into four stages; initiation stage Cl (sporulation stage . III), growth stage C2 (sporulation III to V), envelopment and maturation C3 (sporulation V to V), and finally release stage C4 (sporulation Vll).

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.332-335
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• 2009

Rhizo-bacteria were isolated from organic-farming soils to select antagonistic agent for controlling citrus melanose disease. Among several antagonistic bacteria, KB-401 effectively inhibited mycelial growth of several plant fungal pathogens, including the pathogen of citrus melanose, Diaporthe citri. KB-401 also inhibited spore germination of the fungal pathogen. The tip of germ tube was swollen when conidia of D. citri were co-culture with KB-401 in PD broth amended 1% glucose. KB-401 was identified as Bacillus subtilis through the investigation for physiological characters and the analysis of nucleotide sequences of 16S rDNA.

• Journal of Microbiology
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• v.35 no.2
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• pp.127-133
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• 1997

Biosynthesis of polyhydroxybutyrate and copolymer consisting of 3-hydroxybutyrate and 3-hydroxyvalerate [poly(3HB-co-3HV)] by Bacillus thuringiensis R-510 grown with glucose or with mixtures of glucose and propionate was investigated. n-Alkanoic acids other than propionate were not precursors of 3HV units. The fraction of 3HV unit in the copolymer increased from 0 to 84 mol% of 3HV. Polymer yield decreased as the fraction of propionate was increased but the molecular weight distribution was not affected by the composition of carbon substrate. The minimum melting temperature (around 65.deg.C) of poly (3HB-co-3HV) copolymers was observed for the polymer bearing approximately 35 mol% of 3HV. Polyhydroxyalkanoates production by this organism was not dependent on nutritional limitation, but remarkably influenced by dissolved oxygen concentration in the culture medium. Low level of dissolved oxygen concentration prevented spore formation in the cells and stimulated the synthesis of polyhydroxyalkanoate. The composition of poly (3HB-co-3HV) produced by B. thuringiensis R-510 lyhydroxyalkanoate. The composition of poly(3HB-co-3HV) propduced by B. thuringiensis R-510 varied according to the growth time. However, there was no evidence that polymers isolated from cells were mixtures of immiscible polymers.

• The Plant Pathology Journal
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• v.32 no.3
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• pp.209-215
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• 2016

In this study, the treatment of pistachio nuts by Bacillus subtilis UTBSP1, a promising isolate to degrade aflatoxin B1 (AFB1), caused to reduce the growth of Aspergillus flavus R5 and AFB1 content on pistachio nuts. Fluorescence probes revealed that the cell free supernatant fluid from UTBSP1 affects spore viability considerably. Using high-performance liquid chromatographic (HPLC) method, 10 fractions were separated and collected from methanol extract of cell free supernatant fluid. Two fractions showed inhibition zones against A. flavus. Mass spectrometric analysis of the both antifungal fractions revealed a high similarity between these anti-A. flavus compounds and cyclic-lipopeptides of surfactin, and fengycin families. Coproduction of surfactin and fengycin acted in a synergistic manner and consequently caused a strong antifungal activity against A. flavus R5. There was a positive significant correlation between the reduction of A. flavus growth and the reduction of AFB1 contamination on pistachio nut by UTBSP1. The results indicated that fengycin and surfactin-producing B. subtilis UTBSP1 can potentially reduce A. flavus growth and AFB1 content in pistachio nut.

• Korean Journal of Veterinary Research
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• v.38 no.3
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• pp.574-580
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• 1998

Anthrax caused by Bacillus anthracis is one of the most important zoonotic diseases in the worldwide. To control and prevent the disease effectively, several methods such as development of a fast and specific diagnostic method and vaccine, education etc, have been carried out. However, it still has a problem in the control and prevention. To control, the most important method is the prevention of direct or indirect contact of the causative agent with susceptible host. Therefore, we developed a fast and specific detection method, polymerase chain reaction, of B anthracis from soil and infected animals because the organism could survive long time in the environment including soil due to formation of spore. With the method, virulence genes of B anthracis were successfully amplified from experimentally infected soil and mice. Up to $4.2{\times}10$ of the organisms per gram could be detected with the PCR method from experimentally infected soil. These results suggested that this PCR method could be effectively used not only to detect B anthracis in soil and infected animal but also to provide the information to prevent the disease.

• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.750-758
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• 2013

Anthrax is a bacterial disease caused by the aerobic spore-forming bacterium Bacillus anthracis, which is an important pathogen owing to its ability to be used as a terror agent. B. anthracis spores can escape phagocytosis and initiate the germination process even in antimicrobial conditions, such as oxidative stress. To analyze the oxidative stress response in B. anthracis and thereby learn how to prevent antimicrobial resistance, we performed protein expression profiling of B. anthracis strain HY1 treated with 0.3 mM hydrogen peroxide using a comparative proteomics-based approach. The results showed a total of 60 differentially expressed proteins; among them, 17 showed differences in expression over time. We observed time-dependent changes in the production of metabolic and repair/protection signaling proteins. These results will be useful for uncovering the metabolic pathways and protection mechanisms of the oxidative response in B. anthracis.

• Journal of Microbiology and Biotechnology
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• v.2 no.3
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• pp.183-188
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• 1992

A soil bacterium which produces raw starch-digesting $\beta$-amylase in culture medium, has been screened from soils. One strain, isolated and identified as Bacillus polymyxa No. 26, was selected as a $\beta$-amylase producing bacterium. Morphological and biological characteristics of the strain were found to be similar to those of a strain belonging to B. polymyxa. The electron microscopic observations of the bacterial vegetative cells and sporulated cells were extensively done to know the corelation between the enzyme synthesis and sporulation. When the bacterium was cultured on the appropriate media (3% dextrin, 0.3% beef extract, 0.5% polypeptone, 1% yeast extract and 0.3% NaCl at pH 7.0 for 4 days) raw starch-digestible $\beta$-amylase was produced extracellularly. This strain produced 130 units of $\beta$-amylase per ml in a culture medium containing 3% dextrin at $30^\circ{C}$. This value is compared to those of other $\beta$-amylase-producing strains. The optimum pH and temperature for crude enzymes were pH 6.5 to 7.0 and $50^\circ{C}$, respectively. The enzymes were stable between pH 5.5 and 9.0 for 30 min at $45^\circ{C}$.

• Korean Journal of Microbiology
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• v.22 no.3
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• pp.135-142
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• 1984

The effect of biotin on the growth and sporulation of Bacillus subtilis SNU816 was investigated. When B. subtilis SNU816 was cultured on glucose as a sole carbon source, the growth was retarded markedly and usually ceased at early log phawe. But by addition of biotin to this medium, normal, rapid growth was restored. The growth rate was increased proportionally according to the concentration of exogenous biotin until it reached to 0.05㎍/ml, at which about three fold rapid growth was achieved. Also biotin was required for optimum sporulation for it facilitated the complete utilization of both glucose(Glc) and glutamic acid(Glu). Without biotin in Glc+Glu medium, about 40% of glutamic acid was remained unutilized. The dipicolinic acid content of cells cultured in Glc+Glu medium without biotin was markedly small and sporulation was suppressed before free spore release. Since biotin could be partiallyreplaced by one of TCA cycle intermediates such as oxalacetic acid, citric acid, or glutamic acid in enhancing growth in Glc medium, it was postulated that this strain might have a defect in converting pyruvate to oxalacetate which process is known to be mediated by pyruvate carboxylase that requires biotin as a cofactor.

• Journal of Microbiology and Biotechnology
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• v.5 no.3
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• pp.138-142
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• 1995

Bacillus thuringiensis strain BT-209 was isolated from a soybean grain dust sample in Korea. The strain BT-209 produced two different sizes of cuboidal crystals and one spore in the cell. In the biochemical characterization, the strain BT-209 showed negative reactions on the production of urease, and the utilization of citrate and sucrose. Examination of its antibiotic resistance revealed that while the strain BT-209 showed higher sensitivity than B. thuringiensis subsp. kurstaki HD-1 to ampicillin, bacitracin, chlortetracycline, gentamycin, neomycin, penicillin G, tetracycline and tobramycin, it was more resistant to methicillin than B. thuringiensis subsp. kurstaki HD-1. The $\delta$-endotoxin crystal of strain BT-209 consisted of three proteins with apparent molecular weights of appoximately 148, 135 and 62 kDa on a 10% SDS-PAGE. The strain BT-209 had at least eight different plasmids with sizes of 4.1, 5.2, 6.3, 8.6, 14.6, 24.5, 67.6 and 77.6 Kb. The strain BT-209 showed strong lethalities of 70% and 87% against Bombyx mori and Hyphantria cunea larvae. at 72 h, respectively.