• Pediatric Infection and Vaccine
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• 제26권3호
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• pp.148-160
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• 2019

목적: 본 연구에서는 신생아실과 신생아 중환자실에서 발생한 methicillin-resistant Staphylococcus aureus (MRSA) 유행에서 환자와 보균자에서 분리된 MRSA의 분자역학적 연관성을 조사하여 유행의 감염원과 전파경로를 파악하고자 하였다. 방법: MRSA 유행기간인 2017년 8월부터 9월까지 피부감염 및 패혈증 환자들과 보균자로부터 분리된 MRSA 균주를 대상으로 유전형 및 병원성 인자를 분석하고 항생제 감수성 결과를 수집하였다. 결과: 연구기간 동안 신생아실(n=27)과 신생아 중환자실(n=14)에 총 41명의 신생아들이 입원하였다. 그 중, 7명(피부감염[n=6], 패혈증[n=1])에서 MRSA 감염이 확진되었고, 보균자 4명이 발견되었다. 신생아와 접촉이 있는 의료진 32명 중 3명이 MRSA를 비강에 보균하였다. 피부감염 유행 원인 균주는 Staphylococcal chromosomal cassette mec (SCCmec) type II, sequence type (ST) 89, spa type t375였고, 뮤피로신 저농도 내성을 포함하여 항생제 다제내성을 보였다. 패혈증을 일으킨 균주는 SCCmec type IVa, ST 72, 새로운 spa type인 t17879였다. 신생아 4명에게 집락된 MRSA 균주들은 다양하였으나 SCCmec type IVa, ST 72, spa type t664가 의료진과 신생아 2명에서 공통적으로 분리되었다. Panton-Valentine leukocidin (PVL) toxin 유전자가 신생아에게 집락된 모든 균주에서 발견되었다. 결론: 피부감염 유행을 일으킨 MRSA 균주는 항생제 다제내성을 보이는 균주였다. 신생아 MRSA 보균자에게서 분리된 균주는 모두 PVL 독소 유전자를 보유하였다. 유행기간 동안 다양한 MRSA 균주가 신생아들에게서 분리되기 때문에, 효과적인 감염 관리 및 추가 환자발생의 차단을 위하여 분자역학조사를 통하여 원인균을 확인하고 전파경로를 파악하는 것이 중요하다.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.775-778
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• 2010

A total of 2,858 meat samples collected during 2003-2008 in Korea were investigated, and methicillin-resistant Staphylococcus aureus (MRSA) isolates were isolated from 1.0% (9/890) of beef, 0.3% (4/1,055) of pork, and 0.3% (3/913) of chicken meat samples, respectively. MRSA isolates showed the two sequence types (STs), ST72 from beef and pork and ST692 from chicken meat. MRSA isolates from beef and pork were Panton-Valentine leukocidin-negative, staphylococcal cassette chromosome mec type IVa strain with ST72, which is the most prevalent type of communityacquired MRSA in Korea. An identical pulse-field gel electrophoresis pattern was detected among 10 of 16 MRSA isolates: 9 strains from beef (n=5) and pork (n=4) in 2008, and one strain from beef in 2005.

• 한국임상수의학회지
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• 제25권3호
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• pp.139-145
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• 2008

To investigate the genotypic diversity of the porcine reproductive and respiratory syndrome viruses (PRRSV) in Korea, we examined 92 clinical samples from three provinces by RT-PCR and a nested PCR, and the complete open-reading frame 7 (ORF 7) sequences of 15 samples selected from 72 PCR-positive specimens were analyzed. When we compared nucleotide (amino acid) sequences of 80 isolates from Korea and overseas countries, the sequences of 7 samples belonged to North American (NA)-genotype, and those of 8 samples, to European (EU)-genotype. The nucleotide (amino acid) identities between two genotypes were 63.7% (59.8%) to 65.1% (63.1%). When compared with NA prototype VR-2332, the 7 strains of NA-genotype shared 89.8% (93.6%) to 91.2% (96.0%) identity of nucleotide (amino acid) sequence. The 8 strains of EU-type shared 93.6% (92.3%) to 94.3% (93.8%) identity of nucleotide (amino acid) sequence as compared to EU prototype Lelystad. In phylogenetic tree analysis by neighbor-joining method, all of the 8 EU-type strains were clustered into group 4 distinct from ED-prototype Lelystad (group 1). In NA-genotype, 24 domestic isolates reported previously and the 7 strains of NA-type determined in this study were clustered into group 1, while US prototype VR 2332 was classified into different group (group 2). These results suggest that emergence of EU-genotype and the dual-infection of NA- and EU-genotypes may be prevalent in the pig farms in Korea. The high degree of genetic diversity of field PRRSVs should be taken into consideration for control and preventive measures.

• KSBB Journal
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• 제19권1호
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• pp.72-77
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• 2004

건강에 대한 관심의 증대로 인한 저염식품의 개발 필요성에 맞추어 오이발효에 염의 농도를 낮추게 되면 정상적 일차발효 후에 이차발효가 진행됨으로써 결국 부패하게 된다. 장기간에 걸쳐 다양한 균의 복합적 작용으로 진행되는 저염 발효오이의 부패 과정을 이해하기 위하여 이에 관련된 균을 분리 동정하였다. 부패발효액을 무기배양하여 균을 분리하고 이들의 16s rRNA 유전자 부분을 universal primer를 이용한 PCR로서 증폭하여 서열분석 하였다. 분석된 800 염기 길이의 서열 전체를 그대로 이용하여 NCBI의 BLAST로서 유사종을 찾고 RDP의 Sequence Aligner와 Sequence Match에서 재확인하여 분리된 균을 3속 8종으로 동정하였다. Database 내의 표준균 서열을 기반으로 한 제한효소 지도와 동정된 균의 PCR 생성묵의 제한효소 처리결과(RFLP)를 비교하여 동정 결과를 실험으로 검정하였다. 동정과정에서 sequencing 결과 전체를 이용하는 점과 RDP를 통한 확인과 RFLP를 이용한 검정은 동정 결과에 대한 신뢰도를 한층 증가시켰다. 또 분리된 8종은 개별적 특징의 조사나 적절한 조합을 이룰 때의 상호 의존도 등을 조사할 수 있게 함으로써 여러 균에 의한 복합적 과정인 부패를 순차적 혹은 요인별로 나누어 살펴보는 연구를 가능하게 한다.

• KSBB Journal
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• 제29권1호
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• pp.72-80
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• 2014

CW-4Y was identified as Stenotrophomonas sp. by morphological and physiological characteristics, and phylogenetic analysis of its 16S rDNA gene sequence. Nitrogen removal by CW-4Y was analyzed in relation to the ammonium concentration, presence of organic carbon, carbon source, and carbon-to-nitrogen ratio (C/N). Stenotrophomonas CW-4Y has heterotrophic nitrification and aerobic denitrification abilities. Stenotrophomonas CW-4Y utilized only glucose as carbon sources, and heterotrophic nitrification and aerobic denitrification were observed regardless of the type of nitrogen source. The maximum ammonium removal rate of CW-4Y was 80 $mg-N{\cdot}L^{-1}{\cdot}d^{-1}$ and its denitrification rate of 192 $mg-N{\cdot}L^{-1}{\cdot}d^{-1}$ at $NO_3{^-}-N$ (about 280 ppm) in shake culture experiments at a C/N ratio of about 15 was about 30 times higher than those of other bacteria with the same ability.

• 식물병연구
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• 제27권4호
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• pp.172-179
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• 2021

본 연구에서는 겨울철 사료작물로써 중요성이 증가하고 있는 트리티케일에서 발생한 붉은곰팡이병 원인균의 동정 및 독소 type을 분석하고 트리티케일에 효율적으로 적용 가능한 방제 약제를 선발하고자 분리된 붉은곰팡이 균주의 농약저항성 발생 여부를 분석하였다. 조성, 신조성, 신영, 신성, 세영 등 5개 트리티케일 품종에서 평균 9.15%의 병 발생 이삭률을 보였으며, 병 발생 낱알률은 29.2%로 나타났다. 그 결과 트리티케일에서 발생한 붉은곰팡이병 발생률은 평균 3.52%로 나타났다. 붉은곰팡이병에 감염된 개체로부터 총 91개의 균주가 분리되었으며, 이 중 붉은곰팡이 균주는 총 72개를 분리하였다. 분리한 균주의 형태 및 internal transcribed spacer 1, translation elongation factor 1α 유전자의 염기서열 분석 결과, 트리티케일에서 분리한 균주들은 전부 Fusarium asiaticum으로 동정되었다. 분리 동정된 균주들의 독소 type을 PCR을 통해 분석한 결과, nivalenol (NIV) type 독소는 64.6%, 3-acetyldeoxynivalenol은 4.6%, 15-acetyldeoxynivalenol은 30.8%로 대부분이 NIV type독소를 생성하는 F. asiaticum으로 분석되었다. 최근 봄철 이상 기상현상으로 여러 식량 작물에 붉은곰팡이병 발생률이 높아지고 있다. 트리티케일의 경우 붉은곰팡이병을 방제할 수 있는 등록약제가 없다. 본 실험에서는 보리와 밀에 등록된 약제를 대상으로 트리티케일에서 분리된 붉은곰팡이병 균주들의 약제 내성을 측정한 결과 captan, hexaconazole, difenoconazole·propiconazole 합제는 균사 생장 억제 효과가 있었다. Fludioxonil의 경우 72개 균주 중 6개의 균주가 권장 농도에서 반수영향생육기준치인 42.5 cm를 넘은 47.96±3.15의 균사 생장율을 보여 fludioxonil에 대한 내성이 발생한 것으로 분석되었다. 본 연구는 국내에서 처음 보고 되는 F. asiaticum에 의한 트리티케일의 붉은곰팡이병 발생 사례이며, 또한 붉은곰팡이가 생성하는 독소 타입을 구명하고, 등록 방제 약제가 없는 트리티케일에 효율적으로 방제가 가능한 내성 미발생 약제를 제시하는 중요한 연구 결과이다.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1935-1939
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• 2006

The gene encoding the extracellular medium-chain-length poly(3-hydroxyalkanoate) (MCL-PHA) depolymerase of Pseudomonas luteola Ml3-4, $phaZ_{plu}$, was cloned and analyzed. It was found to be 849 bp, with a deduced protein of 282 amino acids, and was revealed to have a typical leader peptide at its N terminus. The amino acid sequence of $PhaZ_{plu}$ revealed relatively low identity (69 to 72%) with those of other Pseudomonas MCL-PHA depolymerases. In comparison with the amino acid sequences of all available MCL-PHA depolymerases, the depolymerase was found to consist of three domains in sequential order; signal peptide, an N-terminal substrate binding domain, and a catalytic domain, indicating that $PhaZ_{plu}$ belongs to the type IV depolymerases family. The enzyme also contained Asn as an oxyanion hole amino acid.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.69-72
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• 2001

Blind equalization of transmission channel is important in communication areas and signal processing applications because it does not need training sequence, nor does it require a priori channel information. Recently, Tong et al. proposed solutions for this problem exploit the diversity induced by antenna array or time oversampling, leading to the second order statistics techniques, fur example, subspace method, prediction error method, and so on. The linear prediction error method is perhaps the most attractive in practice due to the insensitive to blind equalizer length mismatch as well as for its simple adaptive filter implementation. Unfortunately, the previous one-step prediction error method is known to be limited in arbitrary delay. In this paper, we induce the optimal delay, and propose the adaptive blind equalizer with multi-step linear prediction using RLS-type algorithm. Simulation results are presented to demonstrate the proposed algorithm and to compare it with existing algorithms.

• Journal of Microbiology and Biotechnology
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• 제9권2호
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• pp.196-200
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• 1999

A recombinant human $\alpha_{s1}$-casein was expressed as a secretory product in the yeast Saccharomyces cerevisiae. Three different leader sequences derived from the mating factor $\alpha$l (MF$\alpha$l), inulinase, and human $\alpha_{s1}$-casein were used to direct the secretion of human $\alpha_{s1}$-casein into the extracellular medium. Among the three leader sequences tested, the native leader sequence of human $\alpha_{s1}$-casein was found to be the most efficient in the secretory expression of human $\alpha_{s1}$-casein, which implies that the native leader sequence of human $\alpha_{s1}$-casein might be used very efficiently for the secretory production of other heterologous proteins in yeast. The recombinant human $\alpha_{s1}$-casein was proteolytically cleaved as the culture proceeded. Therefore, an attempt was made to produce human $\alpha_{s1}$-casein using a S. cerevisiae mutant in which the YAP3 gene encoding yeast aspartic protease 3 (YAP3) was disrupted. After 72 h of culture, most of the human $\alpha_{s1}$-casein secreted by the wild type was cleaved, whereas more than 70% of the human $\alpha_{s1}$-casein secreted by yap3-disruptant remained intact. The results suggest that YAP3 might be involved in the internal cleavage of human $\alpha_{s1}$-casein expressed in yeast

• 한국축산식품학회지
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• 제40권5호
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• pp.758-771
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• 2020

This study was to investigate the prevalence and characteristics of antimicrobial-resistant Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) from 4,264 retail meat samples including beef, pork, and chicken in Korea between 2013 and 2018. A broth microdilution antimicrobial susceptibility testing was performed for S. aureus. Molecular typing by multilocus sequence typing (MLST), spa typing, and pulsed-field gel electrophoresis (PFGE), was performed on mecA-positive S. aureus strain. S. aureus was isolated at a rate of 18.2% (777/4,264), of which MRSA comprised 0.7% (29 strains). MLST analysis showed that 11 out of the 29 MRSA isolates were predominantly sequence type (ST) 398 (37.9%). In addition, ST72, ST692, ST188, ST9, and ST630 were identified in the MRSA isolates. The spa typing results were classified into 11 types and showed a high correlation with MLST. The antimicrobial resistance assays revealed that MRSA showed 100% resistance to cefoxitin and penicillin. In addition, resistance to tetracycline (62.1%), clindamycin (55.2%), and erythromycin (55.2%) was relatively high; 27 of the 29 MRSA isolates exhibited multidrug resistance. PFGE analysis of the 18 strains excluding the 11 ST398 strains exhibited a maximum of 100% homology and a minimum of 64.0% homology. Among these, three pairs of isolates showed 100% homology in PFGE; these results were consistent with the MLST and spa typing results. Identification of MRSA at the final consumption stage has potential risks, suggesting that continuous monitoring of retail meat products is required.