• 미생물학회지
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• 제52권2호
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• pp.226-229
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• 2016

먹물버섯 Coprinellus congregatus의 버섯조직이 자가분해되는 시기에 발현되는 chitinase (Chi2)는 사람에게 질병을 일으키는 Cryptococcus neoformans의 세포벽 두께를 정상 세포벽의 32% 수준까지 감소시킬 뿐만 아니라, 세포 외 섬유상 물질도 제거하였다. Chi2 처리에 의하여 사람에게 알레르기를 유발하는 Alternaria alternata의 생장은 물론 생쥐 모델에서 이 균에 의한 피부알레르기 증상도 감소시켰다.

• Journal of Microbiology and Biotechnology
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• 제19권12호
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• pp.1582-1589
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• 2009

Bacterial UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) catalyzes the transfer of enolpyruvate from phosphoenolpyruvate (PEP) to uridine diphospho-N-acetylglucosamine (UNAG), which is the first step of bacterial cell wall synthesis. We identified thimerosal, thiram, and ebselen as effective inhibitors of Haemophilus influenzae MurA by screening a chemical library that consisted of a wide range of bioactive compounds. When MurA was preincubated with these inhibitors, their 50% inhibitory concentrations ($IC_{50}s$) were found to range from 0.1 to $0.7\;{\mu}M$. In particular, thimerosal suppressed the growth of several different Gram-negative bacteria such as Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium at a concentration range of $1-2\;{\mu}g/ml$. These inhibitors covalently modified the cysteine residue near the active site of MurA. This modification changed the open conformation of MurA to a more closed configuration, which may have prevented the necessary conformational change from occurring during the enzyme reaction.

• Journal of Plant Biology
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• 제34권4호
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• pp.261-266
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• 1991

The hairy root was induced form potato tuber disc by infection of a. rhizogenes. The detection of the agropine and mannopine by paper electrophoresis confirmed that induced hairy root was transformed by A. rhizogenes. The activity of peroxidase was the highest at 5 weeks and isozyme pattern of peroxidase revealed 3 cathodic bands and 2 anodic bands and new C4 band(pI 4.6) was observed at 7 weeks after cultivation in hairy root was isoelectric focusing. To study the effect of Ca2+ on cell wall formation in hairy root, channel blocker of Ca2+ was treated. The activity of $\beta$-glucan synthetase II(GS II) related to cell wall synthesis was inhibited by about 50% in diltiazem and flunarizine treatment than that of control, but stimulated in CaCl2 treatment. Therefore these results showed that Ca2+ might be an effective factor in the cell wall formation. The activity of GS II by NaF treatment was increased by about 30%. This result suggested that the activity GS II is changed through phosphorylation process.

• Journal of Microbiology and Biotechnology
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• 제30권12호
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• pp.1827-1834
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• 2020

Candida albicans is a major fungal pathogen in humans. In our previous study, we reported that an ethanol extract from Aucklandia lappa weakens C. albicans cell wall by inhibiting synthesis or assembly of both (1,3)-β-D-glucan polymers and chitin. In the current study, we found that the extract is involved in permeabilization of C. albicans cell membranes. While uptake of ethidium bromide (EtBr) was 3.0% in control cells, it increased to 7.4% for 30 min in the presence of the A. lappa ethanol extract at its minimal inhibitory concentration (MIC), 0.78 mg/ml, compared to uptake by heat-killed cells. Besides, leakage of DNA and proteins was observed in A. lappa-treated C. albicans cells. The increased uptake of EtBr and leakage of cellular materials suggest that A. lappa ethanol extract induced functional changes in C. albicans cell membranes. Incorporation of diphenylhexatriene (DPH) into membranes in the A. lappa-treated C. albicans cells at its MIC decreased to 84.8%, after 60 min of incubation, compared with that of the controls, indicate that there was a change in membrane dynamics. Moreover, the anticandidal effect of the A. lappa ethanol extract was enhanced at a growth temperature of 40℃ compared to that at 35℃. The above data suggest that the antifungal activity of the A. lappa ethanol extract against C. albicans is associated with synergistic action of membrane permeabilization due to changes in membrane dynamics and cell wall damage caused by reduced formation of (1,3)-β-D-glucan and chitin.

• 원예과학기술지
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• 제28권6호
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• pp.1039-1050
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• 2010

당근은 서양뿐만 아니라 중국 및 한국과 같은 아시아 전역에서 요리로 많이 이용되는 유용한 작물 중 하나이다. 그러나 당근 종자 표면에는 모(毛)가 존재하고 이 종모는 발아율을 증가시키기 위해 제거해야 한다. 더욱이 종모 처리는 시간과 인력 및 자본의 소비와 같은 추가적인 손실을 동반하였다. 이러한 문제점을 방지하기 위해 단모종자를 이용하여 모형성과 관련된 유전자의 연구가 필요하다. 당근 종모의 발달은 2차 세포벽의 합성단계 동안 cellulose의 합성 과정과 연관되어 있음을 바탕으로, EST profiling을 통해 종모와 관련된 유전자를 탐색하고자 하였다. 당근 종모 형성에 관련된 유전자 발현을 조사하기 위해, 성숙 초기 단계의 단모종자 659-1개체와 유모종자 677-14개체를 이용하여 cDNA library를 구축하였다. 단모종자 659-1개체와 유모종자 677-14개체에서 확보된 EST 염기서열의 NCBI database BLASTX 분석을 통한 EST profiling 결과, 172개와 224개의 unigene은 이미 알려진 단백질 염기서열과 상동성을 보였으며 나머지 233개와 192개의 unigene은 확인되지 않는 유전자들이었다. EST는 추정되는 기능에 따라 16개의 category로 그룹화되었다. 전체 EST 중 29개의 unigene이 2차 세포벽 합성 단계 동안 cellulose의 합성 pathway상의 종모 형성을 조절하는 유전자로 추정되며, 실제로 종모 발달과 관련된 14개의 unigene이 유모종자 계통에서만 발견되었다.

• 생명과학회지
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• 제2권4호
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• pp.232-239
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• 1992

UDP_GlcNAc is metabolized to form vegetative cell wall, cortical peptidoglycans, and outermost layer consisting of galactosamine-6-phosphate ploysaccharide in life cycle of Bacillus megaterium. To obtain a better understanding of the UDP-GlcNAc regulation, we examined the activity of the common first enzyme for the synthesis of nucleotide precursors of peptidoglycans, enoylpyruvate transferase by newly developed method. Both the specific and the total activity decreased after the end of exponential growth followed by and increase from t5 but decreased again parallel to the appearance of the activity of UDP_GlcNAc-4-epimerase. Antibody specificity to anti-transferase IgG and the elution profile on DEAE-Sepharose revealed that B. megaterium has at least two enoylpyruvate transferase isozymes, and UDP_GlcNAc was metabolized to vegetative cell wall and cortical peptidoglycan by each isozme in exponential growth and in sporulation, respectively in life cycle.

• 한국미생물·생명공학회지
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• 제41권1호
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• pp.88-95
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• 2013

Candida 바이오필름은 숙주조직과 의료기기의 표면에 자라는 자가-조직화된 미생물의 군락으로 전통적인 항진균제에 대한 저항성이 높게 나타난다. 황금(Scutellaria baicalensis)의 뿌리는 극동지방에서 의료용 목적으로 널리 사용되어 왔다. 본 연구의 목적은 10 C. albicans 임상 분리균주에 의해 형성된 바이오필름에 대한 황금의 수용성 추출물의 효과를 평가하고, 항바이오필름 활성에 대한 메커니즘을 알아보는 것이다. 바이오필름에 대한 효과는 XTT 환원분석법을 사용하였으며, 조사된 모든 균주에 대한 대사활성은 MIC에서 유의하게 감소($57.7{\pm}17.3$%)하였다. 황금추출물은 (1,3)-${\beta}$-D-글루칸 합성효소의 활성을 저해하였고 C. albicans의 형태에 대한 황금의 효과는 글루칸 합성의 억제로 인한 생장의 변화와 관련이 있었다: 대부분의 세포는 둥글고 팽창되었으며 세포벽이 진하게 염색되거나 파열되었다. 항캔디다 활성은 살진균성이었고, 황금은 C. albicans를 $G_0/G_1$기에 머물게 했다. 데이터는 황금이 목표가 되는 균류에 다중의 치명적인 효과를 내며, (1,3)-${\beta}$-D-글루칸 합성효소의 활성을 저해함을 통해 궁극적으로는 세포벽의 파열과 죽음에 이르게 한다는 것을 나타낸다. 따라서 황금은 바이오필름과 관련된 캔디다의 감염을 치료하고 제거하기 위한 항진균제 개발 후보 물질로서의 가능성을 가진다.

• Asian-Australasian Journal of Animal Sciences
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• 제6권4호
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• pp.619-622
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• 1993

Rumen bacterial amino acids in sheep on urea diet were monitored to assess a possible change in amino acid synthesis as a long term response to high rumen ammonia environment. A sheep was fed a semipurified diet with soybean meal, followed by a diet with urea as a main nitrogen source. Mixed rumen bacteria were harvested from ruminal fluid taken 3 h after feeding (twice in soybean meal feeding and 6 times in urea feeding) and fractionated as cell wall, proteins and protein-free cell supernatant of monitor amino acids in each fraction. Ruminal ammonia concentration at the sampling ranged from 5.7 to 39.5 mgN/dl. Cell wall and protein fractions of mixed rumen bacteria were stable in their amino acid composition regardless of nitrogen sources of diet and the feeding duration. However, protein-free cell supernatant fraction showed a higher alanine proportion with urea feeding (18.6 and 28.2 molar % of alanine for samples from sheep fed soybean meal and urea, respectively) and its duration (20.6 and 32.9 molar % for samples from sheep on urea diet for 1 and 65 days, respectively). Total free amino acid level of bacteria was depressed in the initial period of urea feeding but restored on 65th day of the feeding. These results suggest that an alanine synthesizing system may develop in rumen bacteria as urea feeding becomes longer.

• Journal of Microbiology
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• 제43권5호
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• pp.398-405
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• 2005

Polyamines such as putrescine are small, ubiquitous polycationic molecules that are required for optimal growth of eukaryotic and prokaryotic cells. These molecules have diverse effects on cell physiology and their intracellular content is regulated by de novo synthesis and uptake from the environment. The studies presented here examined the structure of a putative polyamine transporter (Pot) operon in Streptococcus pneumoniae (pneumococcus) and growth of pneumococci in medium containing putrescine substituted for choline. RT-PCR experiments demonstrated that the four genes encoding the Pot system are co-transcribed with murB, a gene involved in an intermediary step of peptidoglycan synthesis. Pneumococci grown in chemically-defined media (CDM) containing putrescine without choline enter logarithmic phase growth after 36-48 hs. However, culture density at stationary phase eventually reaches that of choline-containing medium. Cells grown in CDM-putrescine formed abnormally elongated chains in which the daughter cells failed to separate and the choline-binding protein PspA was no longer cell-associated. Experiments with CDM containing radiolabeled putrescine demonstrated that pneumococci concentrate this polyamine in cell walls. These data suggest that pneumococci can replicate without choline if putrescine is available and this polyamine may substitute for aminoalcohols in the cell wall teichoic acids.

• 대한약리학회지
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• 제25권1호
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• pp.109-113
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• 1989

사람 혈액속의 elastase와 관련된 질병에 대한 연구는 다양한 저해제의 개발을 동반해 왔으며, 최근 항생제도 그 관심대상이 되고 있다. 두 단계의 액체 크로마토그래피를 거쳐 얻은 고순도의 elastase에 12종의 항생제를 처리하였다. 세포벽합성 저해제로 알려져 있는 penicillin계와 cephalosporin계 항생제를 각각 3종씩 처리한 결과, methicillin과 cefamandole은 10mM 농도에서 elastase 활성을 50% 이상 저해하였지만, 나머지는 거의 10% 미만이었다. 단백질합성 저해제 중 oxytetracycline의 elastase에 대한 저해효과는 10mM 농도에서 95% 이상으로 매우 탁월하였으며 $(IC_{50}=0.3mM)$, gentamicin도 50% 이상 저해하였으나, 다른 aminoglycoside나 chloramphenicol은 역시 10%미만이었다. 실험해 본 항생제 가운데, oxytetracycline, cefamandole, methicillin, gentamicin 등은 elastase에 대한 강력한 저해제였으며, 그 작용기전은 항생제의 알려진 약리학적 기전과는 다른 차원의 모델임이 분명하였다.