• Journal of Microbiology and Biotechnology
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• 제26권2호
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• pp.263-269
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• 2016

Temperate phages have been suggested to carry virulence factors and other lysogenic conversion genes that play important roles in pathogenicity. In this study, phage TEM123 in wild-type Staphylococcus aureus from food sources was analyzed with respect to its morphology, genome sequence, and antibiotic resistance conversion ability. Phage TEM123 from a mitomycin C-induced lysate of S. aureus was isolated from foods. Morphological analysis under a transmission electron microscope revealed that it belonged to the family Siphoviridae. The genome of phage TEM123 consisted of a double-stranded DNA of 43,786 bp with a G+C content of 34.06%. A bioinformatics analysis of the phage genome identified 43 putative open reading frames (ORFs). ORF1 encoded a protein that was nearly identical to the metallo-β-lactamase enzymes that degrade β-lactam antibiotics. After transduction to S. aureus with phage TEM123, the metallo-β-lactamase gene was confirmed in the transductant by PCR and sequencing analyses. In a β-lactam antibiotic susceptibility test, the transductant was more highly resistant to β-lactam antibiotics than S. aureus S133. Phage TEM123 might play a role in the transfer of β-lactam antibiotic resistance determinants in S. aureus. Therefore, we suggest that the prophage of S. aureus with its exotoxin is a risk factor for food safety in the food chain through lateral gene transfer.

• Journal of Microbiology and Biotechnology
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• 제34권6호
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• pp.1322-1327
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• 2024

The accurate and rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) holds significant clinical importance. This work presents a new method for detecting methicillin-resistant Staphylococcus aureus (S. aureus) in clinical samples. The method uses an aptamer-based colorimetric assay that combines a recognizing probe to identify the target and split DNAzyme to amplify the signal, resulting in a highly sensitive and direct analysis of methicillin-resistance. The identification of the PBP2a protein on the membrane of S. aureus in clinical samples leads to the allosterism of the recognizing probe, and thus provides a template for the proximity ligation of split DNAzyme. The proximity ligation of split DNAzyme forms an intact DNAzyme to identify the loop section in the L probe and generates a nicking site to release the loop sequence ("3" and "4" fragments). The "3" and "4" fragments forms an intact sequence to induce the catalytic hairpin assembly, exposing the G-rich section. The released the G-rich sequence of LR probe induces the formation of G-quadruplex-hemin DNAzyme as a colorimetric signal readout. The absorption intensity demonstrated a strong linear association with the logarithm of the S. aureus concentration across a wide range of 5 orders of magnitude dynamic range under the optimized experimental parameters. The limit of detection was calculated to be 23 CFU/ml and the method showed high selectivity for MRSA.

• 한국축산식품학회지
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• 제30권5호
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• pp.730-738
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• 2010

We developed predictive growth models for Staphylococcus aureus and Bacillus cereus on various food matrices consisting primarily of ready-to-eat (RTE) foods. A cocktail of three S. aureus strains, producing enterotoxins A, C, and D, or a B. cereus strain, were inoculated on sliced bread, cooked rice, boiled Chinese noodles, boiled bean sprouts, tofu, baked fish, smoked chicken, and baked hamburger patties at an initial concentration of 3 log CFU/g and stored at 8, 10, 13, 17, 24, and $30^{\circ}C$. Growth kinetic parameters were determined by the Gompertz equation. The square-root and Davey models were used to determine specific growth rate and lag time values, respectively, as a function of temperature. Model performance was evaluated based on bias and accuracy factors. S. aureus and B. cereus growth were most delayed on sliced bread. Overall, S. aureus growth was significantly (p<0.05) more rapid on animal protein foods than carbohydrate-based foods and vegetable protein foods. The fastest growth of S. aureus was observed on smoked chicken. B. cereus growth was not observed at 8 and $10^{\circ}C$. B. cereus growth was significantly (p<0.05) more rapid on vegetable protein foods than on carbohydrate-based foods. The secondary models developed in this study showed suitable performance for predicting the growth of S. aureus and B. cereus on various food matrices consisting of RTE foods.

• 한국응용곤충학회지
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• 제30권3호
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• pp.180-186
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• 1991

배추흰나비 P. rapae와 P. brassicae GV에 대한 봉입체 및 바이러스단백질의 물리화학적 성상을 비교 분석한 결과 전기영동법에 의한 봉입체단백질은 그 분자량이 P. rapae GV는 30kd, P. brassicae GV는 31 kb의 단일단백질이었으며, trypsin, chymotrypsin, papain 및 staphylococcus aureus V8 protease에 의한 peptide mapping에서는 두 바이러스 간에 큰 차이가 없었다. 바이러스입자단백지르이 전기영동법에 의한 분석결과, 두 바이러스 간에 큰 차이가 없었다. 바이러스입자단백질의 전기영동법에 의한 분석결과, 두 바이러스에서 각각 42개의 band가 나타났으며 고분자량 부분에서 P. rapae GV의 경우는 115, 110, 105 및 103 kd의 4개 band인데 반해 P. brassicae GV는 107 kd의 한 band만 관찰되었다. 그리고 봉입체단백질의 아미노산 분석비교에서 두 바이러스 간의 큰 차이는 없었으며 일반적으로 곤충에 많이 존재하는 산성아미노산인 aspartic acid와 glutamic acid의 함량이 많았고 염기성 아미노산에서 lysine의 함량이 특히 많았으며 봉입체단백질의 면역학적인 시험결과에서는 P. rapae GV 항혈청에 대해 두 바이러스는 공통 침강선을 형성하였다.

• 미생물학회지
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• 제27권3호
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• pp.194-200
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• 1989

S. aureus에서 분리된 plasmid pSBK203 상의 CAT 유전자 염기서열을 결정하였으며 유발성 발현현상이 확인되었다. 염기서열 결과에 의해 예측된 단백질의 아미노산 서열 분석결고 pC221-CAT 와는 78%의 가장 높은 상동성을 나타냈으며 pC194-CAT와는 55%, 그람음성균 유래의 CAT 중 하나인 Tn9-CATdhkss 38%의 상동성을 각각 보여주고 있었다.

• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.251-258
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• 2001

In Gram(+) bacteria and organelles in higher eukarotes, $Gln-tRNA^{Gln}$ utilized for protein biosynthesis is formed by a tRNA-dependent amino acid transformation using mischarged $Gln-tRNA^{Gln}$ as the intermediate. In this study, the gatCAB gene encoding $Gln-tRNA^{Gln}$ amidotransferase (Glu-AdT) of Staphylococcus aureus was cloned and its nucleotide sequence wa determined. The S. aureus gatCAB gene was organized in an operon structure consisting of three open reading frames (gatC, gatA, and gatB), similar to that of Bacillus subtilis. The gene sequences for the A and B subunits of$Gln-tRNA^{Gln}$ amidotransferase showed significant homology (77 and 87% homology with amino acid sequence) with the gatA and gatB genes of B. subtilis, yet the C subunit (gatC) showed a relatively lowe homology with the B. subtilis gatC gene and other orthologues. The cloned S. aureus <$Gln-tRNA^{Gln}$ amidotransferase gene was highly expressed in Escherichia coli, and the resulting crude enzyme could convert misacylated <$Gln-tRNA^{Gln}$ into $Gln-tRNA^{Gln}$ in vitro.

• Journal of Microbiology
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• 제33권3호
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• pp.228-233
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• 1995

As S. epidermidis cell was fractionated into cell wall, cell membrane, and cytoplasm, the cell membrane proved to be the most efficient absorbent for lead ion. Utrasonication was effective, when the cells were treated during their exponential growth. The amount of the lead ion adsorbed in cell membrane decreased as hydrogen ion concentration of solution increased. Protein purified from the cell membrane showed higher adsorption capacity for the lead ion than peptidoglycan, teichoic acid from cell wall, or cell membrane lipid. Modification of carboxyl groups in the membrane protein with ethylenediamine and 1-ethyl-3-carbodiimide hydrochloride resulted in a considerable decrease of lead ion adsorption capability, suggesting that the main binding site for lead ion was the carboxyl groups of protein in cell membrane.

• 한국자원식물학회지
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• 제25권5호
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• pp.543-549
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• 2012

대청의 이용성 향상을 위한 자료 확보 측면에서 식물체 부위 및 추출 용매별에 따른 항산화 효소 활성 및 항균효과를 조사하였다. APX(Ascorbate Peroxidase) 활성은 줄기의 에탄올 추출물, 잎의 메탄올 추출물, 잎의 증류수의 추출물 순으로 높아 각각 1601.7, 1133.7 및 524.3(Unit/mg protein)을 나타냈다. CAT(Catalase) 활성은 꽃의 에탄올 추출물, 잎의 메탄올 추출물, 꽃의 증류수 추출물 순으로 높았는데, 각각 177.1, 120.8 및 55.4(Unit/mg protein)를 나타냈다. POD(Ascorbate Peroxidase) 활성은 꽃의 에탄올 추출물, 꽃의 메탄올 추출물, 줄기의 증류수 추출물 순으로 높았으며, 각각 27.1, 14.6 및 10.4(Unit/mg protein)를 나타냈다. SOD(superoxide dismutase) 활성은 뿌리의 증류수 추출물, 꽃의 메탄올 추출물, 뿌리의 에탄올 추출물 순으로 높았으며, 각각 90.8, 80.1, 75.5%를 나타냈다. 대청의 꽃 추출물은 Vibrio parahaemolyticus에 대해서만, 뿌리는 Staphy lococcus aureus에 대해서만, 줄기 추출물은 Bacillus subtilis, Escherichia coli, Staphy lococcus aureus에 대해서만 용매에 관계없이 항균활성을 나타냈다. 특히 대청 잎의 증류수 추출물은 Bacillus subtilis, Escherichia coli에 대해 높은 항균활성을 나타내어 저해환 직경이 각각 30.0 및 24.0 mm이었다. 이와 같은 결과는 약용식물로서 대청의 가치가 높음을 시사해 주었다.

• Journal of Microbiology and Biotechnology
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• 제10권5호
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• pp.656-662
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• 2000

A high level of Staphylococcus haemolyticus L62 lipase was expressed in an Escherichia coli transformant. The expressed lipase activity in the cell-free extract was 70,800 U/l, which corresponded to 30% of the total cellular protein. Pre-mixing of the l62 lipase with some nonionic detergents enhanced its hydrolytic activity towards olive oil: Tween detergents activated the L62 lipase by 3 fold. Gel filtration chromatography of the Tween-80-L62 lipase mixture demonstrated a polymerized complex (∼180 kDa) formed exclusively between Tween-80 and the L62 lipase. The lipase enzyme in the complex showed a higher specific activity towards most triacylglycerols than the intact L62 lipase. The activity enhancement towards each substrate was quite different depending on the acyl chain length; the activity towards tributyrin, trilinolein, and trilinolenin was much more enhanced than the towards the medium and the long-chain saturated triglycerides.

• Journal of Korean Biological Nursing Science
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• 제8권1호
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• pp.5-14
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• 2006

Staphyloccus aureus is one of the most important pathogens in clinical settings. It is also one of the leading causes of nosocomial infections and the dissemination of multiple drug-resistant strains, mainly methicillin resistant Staphyloccus aureus, and the recent emergence of a vancomycin resistant MRSA is the concern to hospital worldwide. MRSA strains have acquired multiple resistance to a wide range of antibiotics, including aminoglycosides and macrolides. $\beta$-Lactam resistance of methicillin-resistnat Staphyococcus aureus is determined by the function of penicillin binding protein 2'(PBP2') encoded by the methicillin resistance gene mec A. MRSA strains carry methicillin resistance gene mecA, encoded by a mobile genetic element designated staphylococoal cassette chromosome mec(SCCmec). MRSA clones are defined by the type of SCCmec element and the genotype of the methicilline-susceptible Staphyococcus aureus chromosome in which the SCCmec element is integrated.