• Journal of Microbiology and Biotechnology
• /
• 제21권11호
• /
• pp.1166-1173
• /
• 2011

Meju is a traditional Korean fermented soy product used as a key element for soy sauce and doenjang. Bacilli with antimicrobial activity were isolated from meju prepared by traditional methods at Sunchang county, Jeollabukdo, Korea. Six isolates were identified as Bacillus amyloliquefaciens by recA gene sequencing and RAPD-PCR. One isolate, B. amyloliquefaciens MJ5-41, showed the strongest fibrinolytic activity. A 27 kDa active fibrinolytic enzyme, AprE5-41, was purified from the culture supernatant of MJ5-41 grown on LB by chromatographic methods. The optimum pH and temperature for purified AprE5-41 were 7.0 and $45^{\circ}C$, respectively. AprE5-41 quickly degraded $A{\alpha}$ and $B{\beta}$ chains but not the ${\gamma}$-chain of fibrinogen. AprE5-41 exhibited the highest specificity for N-succinyl-Ala-Ala-Pro-Phe p-nitroanilide, a known substrate for ${\alpha}$-chymotrypsin, cathepsin G, and subtilisin BPN'. The structural gene, aprE5-41, was cloned by PCR and successfully expressed in B. subtilis.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2006년도 하계학술발표대회 논문집
• /
• pp.621-626
• /
• 2006

Regenerative evaporative cooling is known as an environment-friendly and energy efficient cooling method. A regenerative evaporative cooler (REC) consisting of dry and wet channels is able to cool down the air stream below the inlet wet-bulb temperature. In the regenerative evaporative cooler, the cooling effect is achieved by redirecting a portion of the air flown out of the dry channel into the wet channel and spraying water onto the redirected air. In this study, a horizontal regenerative cooler is considered. In the horizontal regenerative cooler, the flow direction of evaporating water has a right angle to the flow direction of supply air. This difference was investigated with visualization technique and simplified 2-module performance test was done in a thermo-environment chamber. Optimum design configuration is changed due to the wet channel which are easily fully covered with evaporating water and block the air flow inside the channel. Applying the optimized fin configuration design with the highly wetting surface treatment, a regenerative evaporative cooler was fabricated and tested to Identify the cooling performance improvement and operation characteristics. From the experimental results at the intake condition of $32^{\circ}C$ and 50% RH, the supply temperature was measured to be around $23.4^{\circ}C$. The cooling effectiveness based on the inlet dewpoint temperature was evaluated 73% which is almost close to the design expectation.

• Journal of Plant Biotechnology
• /
• 제45권1호
• /
• pp.1-8
• /
• 2018

Meiosis is a specialized cell division, essential in most reproducing organisms to halve the number of chromosomes, thereby enabling the restoration of ploidy levels during fertilization. A key step in meiosis is homologous recombination, which promotes homologous pairing and generates crossovers (COs) to connect homologous chromosomes until their separation at anaphase I. These CO sites, seen cytologically as chiasmata, represent a reciprocal exchange of genetic information between two homologous non-sister chromatids. RAD51, the eukaryotic homolog of the bacterial RecA recombinase, plays a central role in homologous recombination (HR) in yeast and animals. Loss of RAD51 function causes lethality in the flowering plant, Arabidopsis thaliana, suggesting that RAD51 has a meiotic stage-specific function that is different from homologous pairing activity.

• Journal of Microbiology
• /
• 제45권3호
• /
• pp.275-279
• /
• 2007

The aims of this study were to detect Burkholderia cepacia complex (Bcc) strains in a cohort of Cystic Fibrosis patients (n=276) and to characterize Bcc isolates by molecular techniques. The results showed that 11.23% of patients were infected by Bcc. Burkholderia cenocepacia lineage III-A was the most prevalent species (64.3%) and, of these, 10% was cblA positive and 50% esmR positive. Less than half of the strains were sensitive to ceftazidime, meropenem, piperacillin-tazobactam, and trimethoprim-sulfamethoxazole. About half of the strains (41%) had homogeneous profiles, suggesting cross-transmission. The infection by B. cenocepacia was associated to a high rate of mortality (p=0.01).

• 식물병연구
• /
• 제29권1호
• /
• pp.64-71
• /
• 2023

In October 2021, soft rot disease seriously affected radish crop in Dangjin, Chungcheongnam-do, Korea. The infected radishes were stunted and turned dark green, with yellowish leaf foliage. A slimy, wet, and decayed pith region was observed in the infected roots. The bacterial strain KNUB-03-21 was isolated from infected roots. The biochemical and morphological characteristics of the isolate were similar to those of Pectobacterium brasiliense. Phylogenetic analysis based on the sequences of the 16S rRNA region and the concatenated DNA polymerase III subunit tau (dnaX), leucine-tRNA ligase (leuS), and recombinase subunit A (recA) genes confirmed that the isolate is a novel strain of P. brasiliense. Artificial inoculation of radish with P. brasiliense KNUB-03-21 resulted in soft rot symptoms similar to those observed in infected radish in the field; subsequently, P. brasiliense KNUB-03-21 was reisolated and reidentified. To our knowledge, this is the first report of P. brasiliense as a causal pathogen of radish soft rot in Korea.

• 한국식품영양과학회지
• /
• 제25권6호
• /
• pp.1062-1068
• /
• 1996

한국산 주목나무의 부위별 항함효과를 규명하기 위하여 주목나무의 잎, 수피, 그리고 뿌리 부분으로 나누어 알코올 추출물을 제조한 후 변이원성 및 항돌연변이 원성 실험과 인간 암세포주를 이용한 세포성 장 억제효과를 검토하였다. 실험결과 세부분의 에탄올 추출물 수율은 30%정도였다. Bacillus subtillus Hl7 및 M45균주를 이용한 rec-assay와 Salmonella typhimurium TA98 및 TA100 두균주를 이용한 Ames tes에서도 공시 시료 모두 농도 증가에 관계없이 변이원성은 없었다. 그리고 직접 변이 원인 MNNG를 이용한 항돌연변이원성 실험에서는 TA100에서 3가지 추출물 모두 50$\mu\textrm{g}$/plate 첨가시 98%이상의 강한 항돌연변이원성을 나타내었고 4NQO에 대한 억제효과에서는 TA98 및 TA100 모두 두균주에서 98% 이상의 강한 억제효과를 나타내었다. 간접변이원인 Trp-P-1에 대한 돌연변이원성 억제효과에서는 3가지 추출물 투여시 73~89%의 억제효과를 나타내었으며 B(a)P에 대해서는 16~60%의 억제활성을 나타내었으며 그중 뿌리 추출물이 가장 강하였다. 한편 정상간암세포인 WRL68에 대한 세포독성 실험결과 $0.5$\mu\textrm{g}$/{\mu}\ell의$ 농도에서 22~36%의 낮은 세포독성을 나타내었으나, 간암세포인 Hep3B에 $대해서는0.5$\mu\textrm{g}$/{\mu}\ell$ 투여시 잎 추출물 72%, 수피 추출물 87% 그리고 뿌리 추출물이 90%의 강한 세포독성을 나타내었다.

• 한국음향학회지
• /
• 제29권6호
• /
• pp.381-387
• /
• 2010

다채널 오디오 코딩 시스템을 평가함에 있어서 음색 요소뿐만 아니라 공간감 요소 역시 큰 중요성을 갖는다. 이러한 이유로 양이 시간차 왜곡 (Interaural Time Difference Distortion, ITDDist), 양이 크기차 왜곡 (Interaural Level Difference Distortion, ILDDist), 양이 상관관계 왜곡 (Interaural Cross Correlation Distortion, IACCDist)과 같은 공간감 요소를 추가하여 기존의 음질 객관 평가 권고안인 ITU-R Rec. BS. 1387-1을 다채널 오디오 시스템에 적용하기 위한 시도가 있었다. 이 다채널 오디오 시스템을 위한 확장 모델에서는 Duplex 이론에 따라, 양이 시간차 왜곡은 1.5kHz 이하의 저주파 영역에 대해서만 계산되었으며, 양이 크기차 왜곡은 2.5kHz 이상의 고주파 영역에 대해서만 계산되었다. 하지만 고주파 영역에 있어서 포락선의 양이 시간차는 공간감 인지에 있어서, 특히 음상 정위에 있어서 중요한 역할을 한다. 이러한 고주파 영역 포락선의 양이 시간차 공간감 인지에 미치는 영향을 정량적으로 분석하기 위해 해당 인자를 계산하는 방법이 본 논문에서 소개된다. 또한, 이렇게 계산된 고주파 영역 포락선의 양이 시간차는 다채널 오디오의 주관평가 결과와 높은 상관관계를 가짐을 확인한다.

• 한국자기공명학회논문지
• /
• 제19권2호
• /
• pp.95-98
• /
• 2015

Reverse gyrase is a hyperthermophile specific protein which introduces positive supercoils into DNA molecules. Reverse gyrase consists of an N-terminal helicase-like domain and a C-terminal topoisomerase domain. The helicase-like domain shares the three-dimensional structure with two tandem RecA-folds (H1 and H2), in which the subdomain H2 is interrupted by the latch domain (H3). To understand the physical property of the hyperthermophile-specific protein, two subdomains af_H1 and af_H23 have been cloned into E. coli expression vector, pET28a. The $^{15}N$-labeled af_H1 and af_H23 proteins were expressed and purified for heteronuclear NMR study. The af_H1 protein exhibits the well-dispersion of amide signals in its $^1H/^{15}N$-HSQC spectra and thus further NMR study continues to be progressed.

• Neonatal Medicine
• /
• 제16권1호
• /
• pp.76-80
• /
• 2009

저자들은 자궁 내 발육 지연으로 입원한 신새아가 요도하열, 잠복고환, 폐동맥판 협착이 동반되어 시행한 염색체 검사에서 불균형 전도로부터 재조합된 염색체이상의 결과로 8번 염색체 단완 결실과 장완 중복을 보인 1례를 경험하였기에 문헌 고찰과 함께 보고하는 바이다.

• 한국미생물·생명공학회지
• /
• 제49권1호
• /
• pp.9-17
• /
• 2021

A γ-aminobutyric acid (GABA)-producing microorganism was isolated from galchi (hairtail fish, Trichiurus lepturus) jeotgal, a Korean salted and fermented seafood. The G144 isolate produced GABA excessively when incubated in MRS broth containing monosodium glutamate (MSG, 3%, w/v). G144 was identified as Lactobacillus brevis through 16S rRNA and recA gene sequencing. gadB and gadC encoding glutamate decarboxylase (GAD) and glutamate/GABA antiporter, respectively, were cloned and gadB was located downstream of gadC. The operon structure of gadCB was confirmed by reverse transcription (RT)-polymerase chain reaction. gadB was overexpressed in Escherichia coli and recombinant GAD was purified and its size was 54.4 kDa as evidenced by SDS-PAGE results. Maximum GAD activity was observed at pH 5.0 and 40℃ and the activity was dependent on pyridoxal 5'-phophate. The K_m and V_max of GAD were 8.6 mM and 0.01 mM/min, respectively.