• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1546-1554
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• 2010

A bacterial strain capable of producing extracellular ${\alpha}$-galactosidase was isolated from a sample of sugarcane industrial waste. Microbiological, physiological, and biochemical studies revealed that the isolate belonged to Bacillus sp. Furthermore, based on a 16S rDNA sequence analysis, the new isolate was identified as Bacillus megaterium VHM1. The production of ${\alpha}$-galactosidase was optimized based on various physical culture conditions. Guar gum and yeast extract acted as the best carbon and nitrogen sources, respectively. The optimum pH was 7.5 and the enzyme remained stable over a pH range of 5-9. The enzyme was optimally active at $55^{\circ}C$ and thermostable with a half-life of 120 min, yet lost 90% of its residual activity within 120 min at $60^{\circ}C$. One mM concentrations of $Ag^2$, $Cu^2$, and $Hg^{2+}$ strongly inhibited the ${\alpha}$-galactosidase, whereas the metal ions $Fe^2$, $Mn^{2+}$, and $Mg^{2+}$ had no effect on the ${\alpha}$-galactosidase activity, and $Zn^{2+}$, $Ni^{2+}$, and $Ca^{2+}$ reduced the enzyme activity slightly. When treated with the B. megaterium VHM1 enzyme, the flatulence-causing sugars in soymilk were completely hydrolyzed within 1.5 h.

• 한국환경농학회지
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• 제20권2호
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• pp.74-78
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• 2001

아닐린을 유일 탄소원 및 에너지원으로 이용하는 두 개의 균주를 강물에서 분리하였다. 두 개의 세균 균주들은 생리 ${\cdot}$ 생화학적 특성과 16S rRNA 유전자 염기서열을 통하여 모두 Pseudomonas rhodesiae로 동정되었다. 이 균주들은 유일 탄소원으로 아닐린이 6,000 ${\mu}g/mL$ 수준으로 포함되어 있는 최소배지에서도 생육이 가능하였으며 두 균주간의 아닐린 분해능에는 뚜렷한 차이가 없었다. P. rhodesiae 51-C 균주는 아닐린이 300 ${\mu}g/mL$ 수준으로 처리된 최소배지에서 16시간이내에 아닐린을 완전히 분해하였고 아닐린 분해에 대한 최적의 pH는 7.0이었으며, 적온은 $30^{\circ}C$와 $35^{\circ}C$사이였다. P. rhodesiae에 의한 아닐린의 분해는 처음으로 보고하는 바이다.

• 생명과학회지
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• 제18권12호
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• pp.1752-1757
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• 2008

한국의 제주도와 서해안 염전의 해수로 부터 각각 빨강 (JU11-1), 노랑(JU14), 주황(TA20)의 색소를 생성하는 3 균주를 분리하였으며, 이들의 분류학적 특성 및 16S rRNA 서열 분석 결과 3 균주 모두 Pseudoalteromonas 속 세균으로 밝혀졌다. 이들 각각의 색소 최대 흡수파장은 각각 537, 378, 387 nm로 나타났다. 균주는 Marine broth 2216에서 잘 자랐으며, $30^{\circ}C$, 2% NaCl, pH 6-7 의 조건에서 Ju11-1과 Ju14는 배양 24 시간에, TA20은 배양 28 시간에 최대 색소 생성을 나타냈다. 탄소원으로 maltose를 1% 첨가하였을 경우 색소 생성이 우수하였으며, 질소원으로는 beef extract를 1% 첨가하였을 경우 최적의 색소 생성을 나타냈다.

• Molecules and Cells
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• 제28권2호
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• pp.131-137
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• 2009

Plant defensins are small (5-10 kDa) basic peptides thought to be an important component of the defense pathway against fungal and/or bacterial pathogens. To understand the role of plant defensins in protecting plants against the brown planthopper, a type of insect herbivore, we isolated the Brassica rapa Defensin 1 (BrD1) gene and introduced it into rice (Oryza sativa L.) to produce stable transgenic plants. The BrD1 protein is homologous to other plant defensins and contains both an N-terminal endoplasmic reticulum signal sequence and a defensin domain, which are highly conserved in all plant defensins. Based on a phylogenetic analysis of the defensin domain of various plant defensins, we established that BrD1 belongs to a distinct subgroup of plant defensins. Relative to the wild type, transgenic rices expressing BrD1 exhibit strong resistance to brown planthopper nymphs and female adults. These results suggest that BrD1 exhibits insecticidal activity, and might be useful for developing cereal crop plants resistant to sap-sucking insects, such as the brown planthopper.

• 식물병연구
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• 제16권2호
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• pp.158-162
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• 2010

하남성지역의 고추역병 발병포장 건전한 고추뿌리와 근권토양에서 세균 507균주를 분리하였는데, 그중에서 고추역병균에 길항효과가 우수한 G28-6, G28-5, I7-6과 H14-1균주를 선발하였다. In vitro에서 선발된 균주들은 고추역병균의 균사생장, 유주자낭과 유주자 형성, 그리고 피낭포자의 발아를 현저하게 억제하였고, Pot시험에서 선발된 균주 모두 70% 이상의 방제효과를 나타냈고, 포트시험에서 방제효과가 우수하였던 G28-6균주는 고추역병 자연발생 비닐하우스에서 79.4%의 방제가를 보여 공시된 화학농약 80% Mancozeb 보다 훨씬 높은 방제효과를 보였다. 뿐만 아니라 선발된 4균주 모두 in vitro에서 우수한 근권정착능력을 보였다. 고추역병 방제에 우수한 길항세균으로 선발된 G28-6균주의 16S rRNA gene 염기서열분석과 그의 형태적, 생리적 특성들을 Bergey's manual of Systematic Bacteriology를 기준으로 비교하여 Pseudomonas aurantiaca로 동정하였다.

• The Plant Pathology Journal
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• 제29권1호
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• pp.52-58
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• 2013

Fusarium head blight (FHB) caused by the filamentous fungus Fusarium graminearum is one of the most severe diseases threatening the production of small grains. Infected grains are often contaminated with mycotoxins such as zearalenone and trichothecences. During survey of contamination by FHB in rice grains, we found a bacterial isolate, designated as BN1, antagonistic to F. graminearum. The strain BN1 had branching vegetative hyphae and spores, and its aerial hyphae often had long, straight filaments bearing spores. The 16S rRNA gene of BN1 had 100% sequence identity with those found in several Streptomyces species. Phylogenetic analysis of ITS regions showed that BN1 grouped with S. sampsonii with 77% bootstrap value, suggesting that BN1 was not a known Streptomyces species. In addition, the efficacy of the BN1 strain against F. graminearum strains was tested both in vitro and in vivo. Wheat seedling length was significantly decreased by F. graminearum infection. However, this effect was mitigated when wheat seeds were treated with BN1 spore suspension prior to F. graminearum infection. BN1 also significantly decreased FHB severity when it was sprayed onto wheat heads, whereas BN1 was not effective when wheat heads were point inoculated. These results suggest that spraying of BN1 spores onto wheat heads during the wheat flowering season can be efficient for plant protection. Mechanistic studies on the antagonistic effect of BN1 against F. graminearum remain to be analyzed.

• 대한수의학회지
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• 제34권1호
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• pp.115-125
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• 1994

In this study, we try to establish the rapid and specific detection system for Salmonella species. The PhoE gene of Salmonella species was amplified with two specific primers, ST5 and ST8c, using PCR. The probe prepared from the amplified PhoE gene was sequenced and applied for Southern blot analysis. After PCR with ST5 and ST8c primers for PhoE gene, DNA bands of expected size(365bp) from 7 different Salmonella species were detected, but not from 12 enterobacteriaceae and 3 gram positive bacteria. PCR was highly sensitive to detect up to 10fg of purified DNA template and to identify Salmonella species with only 320 heat-lysed bacterial cells. The inhibition of PCR amplification from stool specimen was occurred with 50-fold dilution but disappeared over 100 fold dilution of samples. It was confirmed that the PhoE genes were amplified and cloned with over 97% nacleotide sequence homology of PCR products compared with that of S. typhfmurium LT2. The DNA probe derived from S. typhimurium TA 3,000 showed highly specific and sensitive reaction with PCR products of all tested Salmonella species. These results indicate that PCR was rapid and sensitive detection method for Salmonella species and DNA probe prepared from S. typhimurium TA 3,000 was specific to identify PCR products of different Salmonella species.

• Journal of Microbiology
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• 제41권2호
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• pp.89-94
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• 2003

Bacterial strain No. P08 isolated from wastewater at the Cheongju industrial complex was found to be capable of degrading 4-chlorobenzoate under aerobic condition. P08 was identified as Comamonas sp. from its cellular fatty acid composition and 16S rDNA sequence. The fcb genes, responsible for the hydrolytic dechlorination of 4-chlorobenzoate, were cloned from the plasmid pJJl of Comamonas sp. P08. The fcb gene cluster of comamonas sp. PO8 was organized in the order fcbB-fcbA-fcbTl-fcbT2-fcbT3-fcbC. This organization of the fcb genes was very similar to that of the fcb genes carried on the chromosomal DNA of pseudomonas sp. DJ-12. However, it differed from the fcbA-fcbB -fcbC ordering of Arthrobacter sp. SU. The nucleotide sequences of the fcbABC genes of strain P08 showed 98% and 53% identities to those of Pseudomonas sp. DJ-12 and Arthrobacter sp. SU, respectively. This suggests that the fcb genes might have been derived from Pseudomonas sp. DJ-12 to form plasmid pJSl in Comamonas sp. P08, or that the fcb genes in strain DJ-12 were transposed from Comamonas sp. P08 plasmid.

• 한국환경농학회지
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• 제29권4호
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• pp.388-395
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• 2010

미생물을 이용한 인삼 재배지 내 잔류 tolclofos-methyl의 효과적 분해를 목적으로, tolclofos-methyl에 대한 분해능을 보이는 미생물을 선발하였다. 선발된 미생물은 16S rDNA 염기서열분석을 통하여 Sphingomonas 속으로 동정되었다. 선발 미생물 Sphingomonas sp. 224는 1/10 농도의 LB 배지에 함유된 20 mg/L 농도의 tolclofos-methyl을 배양 72시간 이내에 95% 이상 분해하는 것으로 확인되었다. 또한 이 미생물이 tolclofos-methyl을 분해하여 얻어지는 산물로 2,6-dichloro-4-methyl phenol이 확인됨에 따라 미생물이 생산하는 가수분해 효소에 의한 분해 경로를 가지는 것으로 추정되었다. Tolclofos-methyl 분해 미생물 Sphingomonas sp. 224를 인삼경작지 토양에 처리하여 이들 토양에 잔류되어 있는 tolclofos-methyl에 대한 분해능을 확인 한 결과, 20 mg/Kg 농도의 토양 잔류 tolclofos-methyl에 대하여 14일 이내에 약 50%의 분해력을 보이는 것으로 확인되었다. 이것은 단일 미생물을 이용한 배지 및 토양 내 tolclofosmethyl의 생분해 효과를 처음으로 확인한 연구 결과이다.

• Journal of Life Science
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• 제9권1호
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• pp.26-34
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• 1999

A thermostable pullulanase has been isolated and purified from Thermus caldophilus GK-24 to a homogeneity by gel-filtration and ion-exchange chromatography. The specific activity of the purified enzyme was 431-fold increase from the crude culture broth with a recovery of 11.4%. The purified enzyme showed $M_{r}$ of 65 kDa on denaturated and natural conditions. The pI of the enzyme was 6.1 and Schiff staining was negative, suggesting that the enzyme is not a glycoprotein. The enzyme was most active at pH 5.5. The activity was maximal at $75^{\cire}C$ and stable up to $95^{\cire}C$ for 30 min at pH 5.5. The enzyme was stable to incubation from pH 3.5 to pH 8.0 at $4^{\cire}C$ for 24hr. The presence of pullulan protected the enzyme from heat inactivation, the extent depending upon the substrate concentration. The activity of the enzyme was simulated by $Mn^{2+}$ ion, }$Ni^{2+}$, $Ca^{2+}$, $Co^{2+}$ ions. The enzyme hydrolyzed the ${\alpha}$-1,6-linkages of amylopectin, glycogens, ${\alpha}$, ${\beta}$-limited dextrin, and pullulan. The enzyme caused the complete hydrolysis of pullulan to maltotriose and the activity was inhibited by $\alpha$, $\beta$, or $\gamma$-cyclodextrins. The $NH_{2}$-terminal amino acid sequence [(Ala-Pro-Gln-(Asp of Tyr)-Asn-Leu-Leu-Xaa-ILe-Gly-Ala(Ser)] was compared with known sequences of various sources and that was compared with known sequences of various sources and that was different from those of bacterial and plant enzymes, suggesting that the enzymes are structurally different.