• Journal of Microbiology and Biotechnology
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• 제11권6호
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• pp.986-993
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• 2001

Translation Initiation in prokaryotes involves the formation of a 30 S preinitiation complex, in which translation initiation factors play a role in the stimulation of fMet-tRNA (fMet) binding. However, the specific function and precise mechanism of initiation factor IF1 are still unclear. One a functionally active factor with a high purity. In the present study a large quantity of active IF was rapidly purified, obtained by the overexpression of the infA gene, and then used for a functional study. The induction of infA did not appreciably affect the growth rate of the protease-deficient strain E. coli AR68 harboring the IF1 overproducing plasmid. The level of IF1 obtained was approximately $1-2\%$ of the total cell protein, which enabled the yield of highly purified IF1 (>$98\%$ pure) to be increased to 0.15 mg of IF1/g of cells. The IF1 was isolated within one day by the centrifugatioin of the ribosomal washed fraction, by ammonium sulfate fractionation, chromatography on batch of phosphocellulose, and FPLC Mono S. The overexpressed IF1 was found to be comparable to the factor isolated from normal cells, as determined by migration in NEPHGE/SDS 2-D gels. For binding of fMet-tRNA(fMet) to the 30 S ribosomal subunitis, relatively high levels of binding were obtained when IF2 was present. The addition of IF1 up to 110 pmol proportionally stimulated the binding to a variable extent. This IF1-dependent stimulation of the 30 S preinitiation complex formation demonstrated that IF1 would appear to be exclusively essential for promoting the initiation phase of protein synthesis.

• 한국미생물·생명공학회지
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• 제32권1호
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• pp.96-100
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• 2004

토양 시료를 대상으로 chlorothalonil을 함유한 최소배지에서의 집식배양과 배양 추 HPLC에 의한 잔류분석을 통해 chlorothalonil의 제거 능력이 우수한 균주 Ochrobactrum sp. SH35B를 분리하였다. 분리균 SH35B는 1/10 LB 배지에 함유된 10 ppm의 chlorothalonil을 30시간만에 완전히 제거하였으며, 20 ppm의 chlorothalonil의 경우 30시간 동안 88%를 제거하였다. 분리균의 Glu-SH함량과 glutathione S-transferase활성은 각각 1.33및 62.1 nmol/mg이었으며, 대조균인 E. coli나 B. subtilis 보다 높은 것으로 나타났다. 이상의 결과로부터 chlorothalonil의 전환에 있어서 세포내의 Glu-SH 함량과 glutathione S-transferase 활성 이 중요한 인자로 작용하는 것으로 생각된다.

• Earthquakes and Structures
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• 제9권1호
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• pp.195-219
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• 2015

A partial (hybrid) seismic isolation scheme for precast girder bridges in the form of a "buffer-gap-elastomeric bearings" system has been endorsed in the literature as an efficient seismic design system. However, no guides exist to detail an optimal gap size for different configurations. A numerical study is established herein for different scenarios according to Euro code seismic requirements in order to develop guidelines for the selection of optimal buffer-gap arrangements for various design cases. Various schemes are hence designed for ductile and limited ductility behavior of the bridge piers for different seismic demand levels. Seven real ground records are selected to perform incremental dynamic analysis of the bridges up to failure. Bridges with typical short and high piers are studied; and different values of initial gaps at piers are also investigated varying from a zero gap (i.e., fully locked) condition up to an initial gap at piers that is three quarters the gap left at abutments. Among the main conclusions is that the as-built initial gaps at piers (and especially large gap sizes that are ${\geq}1/2$ as-built gaps at abutments) do not practically reduce the seismic design demand and do not affect the reserve capacity of the bridge against failure for bridges featuring long piers, especially when these bridges are designed a priori for ductile behavior. To the contrary, the "buffer-gap-elastomeric bearings" system is more effective for the bridge schemes with short piers having a large difference between the stiffness of the bearings and that of their supporting (much stiffer) squat piers, particularly for designs with limited ductility. Such effectiveness is even amplified for the case of larger initial as-built gap sizes at piers.

• 한국수산과학회지
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• 제45권1호
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• pp.17-24
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• 2012

We cloned and sequenced the cDNA encoding the $FSH{\beta}$ and $LH{\beta}$ subunits from the pituitary of the blacktip grouper Epinephelus fasciatus, which regulate vitellogenesis and maturation in vertebrates, to achieve stable and healthy gametes. The full-length cDNAs of $FSH{\beta}$ and $LH{\beta}$ were 571 bp and 617 bp, encoding 120 amino acid (aa) and 147 aa proteins, respectively. The deduced amino acid sequences of $FSH{\beta}$ and $LH{\beta}$ were highly homologous (68-97%) to those of other Perciformes; E. bruneus, Dicentrarchus labrax, Thunnus thynnus, and Pseudolabrus sieboldi. Phylogenetic analysis showed that the deduced $FSH{\beta}$ and $LH{\beta}$ amino acid sequences were categorized as a distinct subunit in the $GTH{\beta}$ family, and are closely related to the teleostei $FSH{\beta}$ and $LH{\beta}$, respectively. $FSH{\beta}$ and $LH{\beta}$ mRNA exhibited high abundance in the pituitary gland and low in other brain areas, but were not present in peripheral tissues, as determined by RT-PCR.

• The Korean Journal of Physiology and Pharmacology
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• 제1권2호
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• pp.195-200
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• 1997

Water transport in highly-permeable membranes is facilitated by some specialized pathways, which are called aquaporins (AQP). AQP1 (AQP-CHIP) is the first recognized aquaporin identified from red cells and renal proximal tubules. Up until now 4 other aquaporin homologs have been reported. Each aquaporin has its unique tissue distribution and regulatory mechanims. To elucidate molecular mechanisms for their transcription regulation and tissue-specific expression isolation of aquaporin genes is required. To clone promoters of the AQP family mouse genomic library was screened by the 1st exon-specific probe of AQP4, and 5 different plaques were positively hybridized. Phage DNAs were purified and characterized by restriction mapping and sequencing. One of them is the mouse AQP-CD gene. The gene was consisted of 4 exons and the exon-intron boundaries of mouse AQP-CD gene were identified at identical positions in other related genes. The 5'-flanking region of AQP-CD gene contains one classic TATA box, a GATA consensus sequence, an E-box and a cyclic AMP-responsive element. The cloning of the mouse AQP-CD gene, of which product is expressed in the collecting duct and is responsible for antidiuresis by vasopressin, will contribute to understand the molecular mechanisms of tissue-specific expression and regulation of AQP-CD gene under various conditions.

• 환경위생공학
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• 제1권1호
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• pp.59-67
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• 1986

This sanitary survey was carried out to investigate the bacteriological contamination of cooking utensils and foods of moving tavern in eight sample sites of Seoul area. The results of survey were as follows: 1. The counts by means of total bacteria in cooking utensils and food samples by standard plate count method were as follow: $5.6\times10^5$ per gm in dishcloth, $3.1\times10^6$ per ml in dishwater. In food samples, $5.4\times10^5$ per gm in meat was higher than other samples. 2. The average counts total coliform and fecal coliform in samples by MPN method were as follow: $3.4\times10^4$ MPN per 100ml, and $1.3\times10^2$ MPN per 100ml in chopping board, $6.1\times10^4$MPN per gm and $1.0\times10^2$ MPN per gm in dishcloth, $1.8\times10^5$ MPN per 100ml and $6.1\times10^2$ MPN per 100ml in dishwater. In food samples, $3.1\times10^4$MPN per gm and $2.0\times10^2$ MPN per gm in meat was higher than other samples. 3. The counts by means of Pseudomonas in samples by MPN method were as follow: $2.8\times10^3$ MPN per 100ml in chopping board, $4.7\times10^3$ MPN per gm in dishcloth $5.6\times10^3$ MPN per 100ml in dishwater. In food samples, $2.4\times10^3$ MPN per gm in shellfish was higher than other samples. 4. Isolation cases of Food poisoning organisms from samples were as follow: Staphylococci was detected 9 cases $(17.6\%)$ in chopping board, 7 cases $(13.6\%)$ in dishcloth. In food samples, 9 cases $(25.7\%)$ in meat, 1 case $(4\%)$ in fish samples. Salmonella was detected 2 cases $(3.9\%)$ in dishwater, 1 case in meat samples.

• Macromolecular Research
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• 제15권6호
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• pp.498-505
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• 2007

This study demonstrated the in-situ functionalization with polymers of multi-walled carbon nanotubes (MWNTs) via emulsion polymerization. Polystyrene-functionalized MWNTs were prepared in an aqueous solution containing styrene monomer, non-ionic surfactant and a cationic coupling agent ([2-(methacryloyloxy)ethyl]trime-thylammonium chloride (MATMAC)). This process produced an interesting morphology in which the MWNTs, consisting of bead-string shapes or MWNTs embedded in the beads, when polymer beads were sufficiently large, produced nanohybrid material. This morphology was attributed to the interaction between the cationic coupling agent and the nanotube surface which induced polymerization within the hemimicellar or hemicylindrical structures of surfactant micelles on the surface of the nanotubes. In a solution containing MATMAC alone without surfactant, carbon nanotubes (CNTs) were not well-dispersed, and in a solution containing only surfactant without MATMAC, polymeric beads were synthesized in isolation from CNTs and continued to exist separately. The incorporation of MATMAC and surfactant together enabled large amounts of CNTs (> 0.05 wt%) to be well-dispersed in water and very effectively encapsulated by polymer chains. This method could be applied to other well-dispersed CNT solutions containing amphiphilic molecules, regardless of the type (i.e., anionic, cationic or nonionic). In this way, the solubility and dispersion of nanotubes could be increased in a solvent or polymer matrix. By enhancing the interfacial adhesion, this method might also contribute to the improved dispersion of nanotubes in a polymer matrix and thus the creation of superior polymer nanocomposites.

• 한국동물위생학회지
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• 제29권3호
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• pp.277-285
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• 2006

Plasmids are covalently closed circular molecules of DNA that are stably inherited and replicate somewhat independently of the bacterial chromosome. Genes carried on plasmids can mediate a wide variety of important functions, including antibiotics (R plasmids) and heavy metals resistance, toxins production, cell penetration, iron chelation, complement resistance, and metabolic characteristics such as sucrose and lactose fermentation. Fifty strains of lactobacilli were isolated from 26 staters and 29 fermented milk products. They were classified 27 strains as Lactobacillus paracasei subsp paracasei, 11 stains as Lactococcus lactis subsp cremoris, 6 strains as L delbrueckii subsp lactis, 4 strains as L acidophius, and 2 strains as L delbrueckii subsp bulgaricus. All of these strains were examined for drug resistance and transferability of R plasmids. All of the isolates were sensitive to Am, C, CF, E, NB, P, T, and Te. But resistant to SXT 94% (47 strains), K 66% (33 strains), S 56% (28 strains), ENR 50% (25 strains), NOR 38% (19 strains) CIP 38% (19 strains), GM 16% (8 strains), and N 14% (7 strains), in order. And 32 different resistant patterns were found. The most frequently encountered patterns were CIP-ENR-K-NOR-S-SXT (5 strains). In vitro R plasmids transfer experiment, 57 antibiotic resistant strains which were not transfer to the recipient 2 Escherichia coli strains by conjugation, These results indicate that Lactobacillus in internal trade market' stater recognize R factor but transmissible R plasmid is not existed.

• 한국동물위생학회지
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• 제32권3호
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• pp.241-249
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• 2009

Shiga toxin (Stx)-producing Escherichia coli (STEC) strains can cause broad spectrum of human disease, including diarrhea, hemorrhagic colitis, and the life-threatening hemolytic uremic colitis (HUS). We examined 868 samples was taken from bovine feces and carcass from January to December 2008 in Seoul. Twenty two (9.5%) shiga toxin -producing Escherichia coli were isolated from the 230 of bovine feces, and two (0.31%) were isolated from the 638 of carcasses. Serotype of E. coli isolates were O157 (10, 41.6%), O26 (10, 41.6%), O111 (1, 4.2%) and UT (3, 12.6%). In PCR, the isolates displayed three different stx gene combination (stx1 [2, 8.4%]), stx2 [3, 12.6%] and stx1 and stx2 [19,87.5%]). The eaeA and hlyA gene were found in 11 (45.8%) of the 24 strains. Saa gene was present only one strains (4.2%). Toxin typing using reverse passive latex agglutination test showed the same result in VT 1. But it showed different result in VT 2. In antimicrobial susceptibility test, all isolates were sensitive to amikacin, amoxicillin/clavulanic acid, ciprofloxacin and colistin. Eighteen strains (75.0%) of 24 isolates showed the multi-resistant patterns with over 3 drugs. PFGE was performed after the genomic DNA of twenty four isolates was digested with Xba I. the 24 isolates showed 7 (A~G) PFGE type.

• 한국식품저장유통학회지
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• 제10권1호
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• pp.89-93
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• 2003

표고버섯을 새로운 형태의 식품으로 개발하기 위한 기초 자료와 천연보존료로의 이용 가능성을 검토하고자 물과 에탄올로 항균성 물질을 추출하여 몇 종의 병원균, 식중독균, 식품과 관련이 있는 세균 및 효모등 10균주에 대하여 항균성 여부와 추출물의 최소저해 농도를 밝히고, 표고버섯추출물을 용매 계통 분획하여 항균활성을 살펴보았다. 항균성 검색에 사용된 물과 에탄을 추출물 모두에서 대부분의 세균은 항균활성이 나타났으나, 효모와 젖산균에서는 나타나지 않았다. 또한 에탄을 추출물이 물 추출물보다 더 강한 활성을 보였으며 대보다는 갓에서 항균활성이 다소 강하게 나타났다. 표고버섯의 항균활성을 균주별로 보면 E. coli에서 첨가농도가 0.5 mg/mL로 가장 낮아 높은 활성을 나타냈고, 젖산균과 효모등의 균주에서는 1.5 mg/mL 이상의 농도에서도 항균효과가 나타나지 않았다. 표고버섯 에탄을 추출물중의 항균활성 물질은 121$^{\circ}C$에서 15분간 가열한 후에도 활성이 유지되었으며, pH의 변화에도 영향을 받지 않았다. 표고버섯 에탄을 추출물을 핵산, 에테르, 에틸아세테이트 및 물로 용매계통 분획하여 얻은 각 분획물의 항균활성은 세균의 경우 젖산균을 제외한 그람양성균과 그람음성균 모두 에틸아세테이트 분획물에서 현저한 생육 억제효과가 나타났으며, 에테르와 핵산 분획물에서도 에틸아세테이트 분획물 보다는 낮지만 대부분의 균주에 대하여 항균활성을 보였다. 그러나 젖산균과 효모에서는 모든 분획물에서 항균효과가 거의 없었다.