• Molecules and Cells
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• 제19권1호
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• pp.23-30
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• 2005

Spinocerebellar ataxia type 1 (SCA1) is an autosomal-dominant neurodegenerative disorder caused by expansion of the polyglutamine tract in the SCA1 gene product, ataxin-1. Using d2EGFP, a short-lived enhanced green fluorescent protein, we investigated whether polyglutamine-expanded ataxin-1 affects the function of the proteasome, a cellular multicatalytic protease that degrades most misfolded proteins and regulatory proteins. In Western blot analysis and immunofluorescence experiments, d2EGFP was less degraded in HEK 293T cells transfected with ataxin-1(82Q) than in cells transfected with lacZ or empty vector controls. To test whether the stability of the d2EGFP protein was due to aggregation of ataxin-1, we constructed a plasmid carrying $ataxin-1-{\Delta}114$, lacking the self-association region (SAR), and examined degradation of the d2EGFP. Both the level of $ataxin-1-{\Delta}114$ aggregates and the amount of d2EGFP were drastically reduced in cells containing $ataxin-1-{\Delta}114$. Furthermore, d2EGFP localization experiments showed that polyglutamine-expanded ataxin-1 inhibited the general function of the proteasome activity. Taken together, these results demonstrate that polyglutamine-expanded ataxin-1 decreases the activity of the proteasome, implying that a disturbance in the ubiquitin-proteasome pathway is directly involved in the development of spinocerebellar ataxia type1.

• Journal of Microbiology
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• 제37권1호
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• pp.14-20
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• 1999

Two extracellular proteases, EP I and EP II, from cells of Oligotropha carboxydovorans (formerly Pseudomonas carboxydovorans) DSM 1227 grown in nutrient broth were purified to greater than 95% homogeneity in five steps using azocasein as a substrate. The final specific activities of EPs I and II were 214.9 and 667.4 units per mg of protein. The molecular weights of native EPs I and II were determined to be 23,000. Sodium dodecyl sulfate-gel electrophoresis revealed the two enzymes to be monomers. The enzymes were found to be serine-type proteases. The activity of EP I was stimulated by Ca2+, Mg2+, and Ba2+, but that of EP II was not. The enzymes were completely inhibited by Fe2+, Hg2+, Co2+, Zn2+, and Cd2+. EDTA and EGTA exhibited a strong inhibitory effect on EP I. The optimal pH for the two enzymes was pH 9.0. The optimal temperatures for EP I and II were 60 and 50$^{\circ}C$, respectively. The enzymes were stable under alkaline conditions. The thermal stability of EP I was higher than that of EP II. Cell-free extracts did not inhibit the purified enzymes. The enzymes were active on casein, azocasein, azocoll, and carbon monoxide dehydrogenase, but weakly active with bovine serum albumin.

• 한국축산식품학회지
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• 제38권6호
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• pp.1315-1321
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• 2018

Bacteriocin is ribosomally synthesized by bacteria and inhibits closely related species. In this study we aimed at isolating lactic acid bacteria producing bacteriocin presenting anti-staphylococcal activity. A Lactococcus lactis strain was isolated from kimchi for the purpose and identified by 16S rRNA gene sequencing. As preliminary tests, optimal culture conditions, stabilities against heat, solvents, and enzymes treatments, and type of action (bacteriostatic or bactericidal) of the bacteriocin were investigated. The optimal culture conditions for production of the bacteriocin were MRS broth medium and $25^{\circ}C$ and $30^{\circ}C$ culture temperatures. The bacteriocin was acidic and the activity was abolished by a protease treatment. Its stability was maintained at $100^{\circ}C$ for 15 min and under treatments of various organic solvents such as methanol, ethanol, acetone, acetonitrile, and chloroform. Finally, the bacteriocin showed bactericidal action against Staphylococcus aureus where 200 AU/mL of the bacteriocin decreased the viable cell count (CFU/mL) of S. aureus by 2.5 log scale, compared with a control (no bacteriocin added) after 4-h incubation.

• 한국미생물·생명공학회지
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• 제52권1호
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• pp.55-64
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• 2024

The desire of modern people to maintain a healthy and beautiful appearance is increasing day by day along with the increasing interest in skin health and the demand for functional cosmetics. Accordingly, research on functional cosmetic materials with few side effects and excellent efficacy is being actively conducted. Therefore, this study tried to verify the antioxidant and whitening effects of the mixed extracts of Bixa orellana, Ammi majus, and Glycyrrhiza glabra, whose efficacy has been individually verified. Extracts (BAG-1~4) with different extraction methods such as steaming, fermentation, and ultrasonication were prepared for 3 types of natural plants, and antioxidant and whitening effects of these extracts were confirmed. For this purpose, antioxidant, tyrosinase activity, melanin production and stability experiments were conducted. Extracts (BAG-1~4) had no cytotoxicity, and antioxidant and whitening effects were confirmed. BAG-4 extracted by steaming and fermentation showed the best efficacy. It seems that enzymes such as lipase, protease, and amylase increase phenol components by various yeasts involved in the fermentation process, thereby improving antioxidant and melanin production inhibitory effects. It was confirmed that the three types of natural plant extracts could be used as safe and functional cosmetic materials.

• BMB Reports
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• 제57권8호
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• pp.369-374
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• 2024

Antigen 43 (Ag43) proteins, found on the outer membrane of Escherichia coli, are β-sheets that fold into a unique cylindrical structure known as a β-barrel. There are several known structural similarities between bacterial Ag43 autotransporters and physical components; however, the factors that stabilize the barrel and the mechanism for Ag43 passenger domain-mediated translocation across the pore of the β-barrel remain unclear. In this study, we analyzed Ag43β-enhanced green fluorescent protein chimeric variants to provide new insights into the autotransporter Ag43β-barrel assembly, focusing on the impact of the α-helical linker domain. Among the chimeric variants, Ag43β700 showed the highest surface display, which was confirmed through extracellular protease digestion, flow cytometry, and an evaluation of outer membrane vesicles (OMVs). The Ag43β700 module offered reliable information on stable barrel folding and chimera expression at the exterior of the OMVs.

• 생명과학회지
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• 제27권7호
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• pp.805-811
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• 2017

이전의 논문에서 된장으로부터 섬유소와 지질, 녹말, 그리고 단백질을 포함하는 다양한 유기물을 가수분해하는 세균을 분리한 바 있다. 본 연구에서는 분리균주인 Bacillus subtilis CK-2가 생산하는 각종 가수분해효소의 조효소 특성을 확인하였다. 섬유소분해효소의 경우 적정 수소이온농도는 pH 5.0, 적정온도는 $55^{\circ}C$로 확인되었으며, pH 5.0~10.0과 $20{\sim}50^{\circ}C$의 범위에서 높은 활성을 나타내었다. 섬유소분해효소는 $Co^{2+}$ 이온에 의해 활성이 높아지며, 0.45%(w/v)의 $Co^{2+}$ 이온 농도에서 가장 높은 활성을 보였다. 녹말분해효소의 경우 적정 수소이온농도는 pH 5.0, 적정온도는 $50^{\circ}C$로 확인되었으며, pH 4.0~5.0과 $20{\sim}50^{\circ}C$의 범위에서 높은 활성을 나타내었다. 녹말분해효소는 $Co^{2+}$ 이온에 의해 활성이 높아지며, 0.2%(w/v)의 $Co^{2+}$ 이온 농도에서 가장 높은 활성을 보였다. 단백질분해효소의 경우 적정 수소이온농도는 pH 8.0, 적정온도는 $50^{\circ}C$로 확인되었으며, pH 7.0~8.5과 $20{\sim}50^{\circ}C$의 범위에서 높은 활성을 나타내었다. 섬유소분해효소는 $Mn^{2+}$ 이온에 의해 활성이 높아지며, 0.125%(w/v)의 $Mn^{2+}$ 이온 농도에서 가장 높은 활성을 보였다. 이러한 결과로부터 B. subtilis CK-가 생산하는 가수분해효소를 산업적으로 이용하기 위해서는 효소의 종류에 따라 수소이온농도와 온도, 그리고 금속이온을 적절하게 조절할 필요가 있다는 것을 알 수 있다.

• 한국축산식품학회지
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• 제27권3호
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• pp.363-370
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• 2007

김치의 L. plantarum의 생균제적 특성을 조사하기 위하여 김치에서 산생산과 성장능력 등이 우수한 25종의 Lactobacillus sp.를 분리하였고, API kit 분석에 의하여 L. plantarum을 동정하고 재차 16S rDNA 염기서열(99.9% 상동성)을 비교한 후 L. plantarum JK-01로 표기하였다. L. plantarum JK-01은 MRS broth에서 배양시 18시간 후 $2.9{\times}10^{10}CFU/ml$로 최대로 증식하는 빠른 성장특성을 나타냈으며 pH도 4.5로 조속히 하강하였다. 효소활성은 xylanase, amylase, protease, phytase의 순으로 높은 활성을 포함하고 있는 것으로 예측되었다. L. plantarum JK-01은 pH 2에서도 $1.36{\times}10^5CFU/mL$가 생존하였고, 1%의 담즙산에서도 약 $10^6CFU/mL$이상이 생존하여 내산성과 내담즙산성이 강한 것으로 나타났다. 또, $60^{\circ}C$에서도 $3.3{\times}10^3$ CFU/mL 정도로 생존하는 내열성이 있었으며, 대장균과 함께 배양시 18시간 후 대장균을 사멸시키는 것으로 나타났다. 이상의 결과로부터 분리한 L. plantarum JK-01은 생균제로서 충분히 이용가치가 있는 것으로 사료되었다.

• 한국수산과학회지
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• 제19권1호
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• pp.20-26
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• 1986

Very little information is available in the literature on storage of fish sauce. Therefore, microbiological and chemical chracteristics during storage and quality of fish sauce were investigated and discussed to present data about the optimum storage condition. The chopped sardine meat was mixed with equal amount of water and $9\%$(w/w) of $75\%$ vital wheat gluten and then hydrolyzed by addition of commercial proteolytic enzymes such as bromelain, papaya protease, ficin and a enzyme mixture (Pacific Chem. Co.) for 4 hours at $52.5^{\circ}C$. The reaction mixture was heated for 30 min at $100^{\circ}C$ for enzyme inactivation, pasteurization and color development and then centrifuged for 20 min at 4,000 rpm. Table salt and benzoic acid were added for bacteriostatic effect and stored for 80 days at $15{\pm}1^{\circ}C$ and $30{\pm}1^{\circ}C$. The results were summarized as follows: 1. The amount of amino-nitrogen and pH of fish sauce were almost unchanged during storage. 2. Mininum concentration of salt for bacteriostatic activity was $9\%$(w/w) regardless of addition of benzoic acid. 3. the yields of amino-nitrogen were $63.1\%$ for the hydrolysate prepared without enzyme, $79.7\%$ for that with bromelain, $69.9\%$ with ficin, $74.3\%$ with papaya pretense, and $78.1\%$ with enzyme mixture, respectively. 4. The contents of amino-nitrogen were $4510.0mg\%$ on the dry basis for the product prepared by autolysis, $5483.2mg\%$ for that prepared with bromelain, $5305.7mg\%$ with ficin, $4994.1mg\%$ with papaya protease and $5582.3mg\%$ with the enzyme mixture, respectively. 5. The contents of crude protein were $51.35\%$ on the dry basis for the product prepared by autolysis and 55 to $59\%$ for prepared with commercial enzymes. 6. The hydrolysate prepared with the enzyme mixture revealed a little stronger meaty taste than any other products. 7. The level of crude protein in residues was still high ($69.5{\sim}77.2\%$ on the dry basis) and might be originated from the added vital wheat gluten.

• 한국양식학회지
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• 제21권3호
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• pp.190-195
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• 2008

본 연구는 Paracyclopina nana의 먹이생물로써의 우수성을 핵산과 소화효소 활성을 기준으로 넙치 Paralichthys olivaceus 자어를 대상으로 밝히기 위한 것이었다. 실험은 P. nana 단독구(C 실험구), Artemia nauplii 단독구(A 실험구) 그리고 혼합구(M 실험구)로 나누어서 실시하였다. 넙치 자어의 체장은 부화 28일째, P. nana 단독 공급구에서 높게 나타났다. 건조중량당 핵산 함량은 C, M 실험구에서 A 실험구보다 함량이 빠르게 증가하였으며, RNA/DNA ratio는 C 실험구가 M, A 실험구보다 감소 경향이 빨랐다. 이들 자어의 생존률은 실험구에 따른 차이는 없었지만, 비색소침착률은 C, M 실험구에서 낮게 나타났으며, 실험 종료 시 변태율은 C 실험구에서 가장 높게 나타났고, A 실험구에서 유의적으로 가장 낮게 나타났다. $\alpha$-amylase 활성은 모든 실험구에서 증가하는 활성의 경향을 보였다. TAP 활성은 A 실험구에서 26일째 이후 9 mU/larva의 활성으로 높게 나타났으나, 다른 실험구에서는 $5{\sim}6$ mU/larva로 증가하지 않았다. $TAP/{\alpha}-amylase$ 활성의 비에서 A 실험구는 실험기간 동안 유의적으로 변화가 없었으나, C, M 실험구는 유의적으로 낮아지는 경향을 보였다. 결과적으로 실험구들의 성장, 핵산 함량의 변태와 관련된 시기적 증감 현상, 그리고 C, M 실험구에서 지속적으로 낮아지는 $TAP/{\alpha}-amylase$ 활성비를 보았을 때, 넙치 자어의 가장 높은 성장률을 볼 수 있었던 요각류인 P. nana를 공급하는 것이 이 시기의 효과적인 사육 방법인 것으로 판단된다.

• Applied Biological Chemistry
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• 제33권4호
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• pp.330-336
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• 1990

젓갈에서 분리한 단백질분해균을 이용하여 속성 저식염 멸치젓의 제조조건과 저장중의 품질 안정성에 대하여 실험한 결과 저식염 멸치젓의 제조조건은 생멸치 100g에 대해 식염 1%, B. licheniformis p-5균 배양액 20m1($3.2{\times}10^{4}cells/ml$), sodium erythorbate 1%를 첨가한 후 $40^{\circ}C$, pH7.0에서 15시간 진탕배양(45strokes/min)시킨 후 저장성과 풍미를 고려하여 NaCl 3%, KCl 4%, 에탄을 4%(w/v), 마늘 및 생강가루 각각 0.5%씩 첨가하는 것이며, 저장중 휘발성 염기질소는 서서히 증가하였고, 히스타민 함량은 제조 직후 17.6mg/100g으로 위생상 안정하였다. 그리고 첨가된 Bacillus 속이 저장기간 동안 총균수의 상당량을 지배하였으며, 유리 아미노산 함량이 분석된 정미성분의 대부분을 차지하였다. 휘발성 성분중 휘발성산이 젓갈의 냄새에 기여도가 켰으며 다음으로 카르보닐 화합물, 염기의 순이었다.