• Journal of Microbiology and Biotechnology
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• 제31권2호
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• pp.259-271
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• 2021

Many bacteria metabolize aromatic compounds via catechol as a catabolic intermediate, and possess multiple genes or clusters encoding catechol-cleavage enzymes. The presence of multiple isozyme-encoding genes is a widespread phenomenon that seems to give the carrying strains a selective advantage in the natural environment over those with only a single copy. In the naphthalene-degrading strain Pseudomonas putida ND6, catechol can be converted into intermediates of the tricarboxylic acid cycle via either the ortho- or meta-cleavage pathways. In this study, we demonstrated that the catechol ortho-cleavage pathway genes (catBICIAI and catBIICIIAII) on the chromosome play an important role. The catI and catII operons are co-transcribed, whereas catAI and catAII are under independent transcriptional regulation. We examined the binding of regulatory proteins to promoters. In the presence of cis-cis-muconate, a well-studied inducer of the cat gene cluster, CatRI and CatRII occupy an additional downstream site, designated as the activation binding site. Notably, CatRI binds to both the catI and catII promoters with high affinity, while CatRII binds weakly. This is likely caused by a T to G mutation in the G/T-N11-A motif. Specifically, we found that CatRI and CatRII regulate catBICIAI and catBIICIIAII in a cooperative manner, which provides new insights into naphthalene degradation.

• 폴리머
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• 제25권5호
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• pp.736-743
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• 2001

N,N-Methylenebisacrylamide (MBAA)로 가교 결합된 electro-active 고분자(EAP) (poly(2-acrylamido-2-methylpropane sulfonic acid), PAMPS) 겔을 수용액 상에서 potassium persulfate를 개시제로 하여 라디칼 중합시켜 제조하였다. PAMPS 겔의 구동성을 부여하기 위하여 계면활성제로 팽윤하며 치환하였다. 계면활성제가 치환된 PAMPS 겔은 용액내의 인가된 전압하에서, 그 전기장 변화에 의해 큰 변위를 나타내는 구동특성을 보였다. PAMPS 겔은 빠른 응답속도와 가역적인 bending을 나타내었다. 겔의 구동원리는 양극과 PAMPS 겔 음이온간의 정전기 인력, 겔의 swelling-deswelling 효과 그리고 계면활성제의 소수성 반응의 협동적 과정으로 나타난다. PAMPS 겔의 응답속도는 인가된 전압 및 가교도가 증가할수록 증가하였으며, 구동이 반복적으로 진행됨에 따라 응답속도는 증가하였다. 겔의 두께가 증가하면 응답속도는 감소하였다.

• 한국콘텐츠학회논문지
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• 제6권10호
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• pp.163-173
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• 2006

섬유 패션 산업은 소비자의 구매 욕구를 예측하여 제품을 개발하는 경우가 빈번하며, 예측이 잘못될 때는 즉 소비자들이 특정제품을 외면하는 경우 할인판매를 통해 제품을 처리해야 하는 문제점을 안고 있다. 반면에 신속대응 시스템은 소비자의 욕구를 지속적으로 관찰하여 신속하게 제품개발 및 생산일정을 수립함으로써 불필요한 재고가 쌓이는 경우를 사전에 방지할 수 있게 한다 소비자의 욕구는 POS 시스템에서 창출되는 자료를 통해 수집 분석되고 이런 소비자의 선호도는 네트워크를 통해 실시간으로 관련 제조업자에게 제공되어 제조업자들이 소비자의 선호도에 부합하는 제품을 개발, 생산, 제공할 수 있도록 해준다. 본 연구에서는 신속대응 시스템의 주요한 목표인 신기술의 접목을 통하여 의류제품의 기획, 구매, 생산, 유통과정 상의 재고 수준의 절감 및 과정 소요기간의 단축, 의류제조업자와 소매업자간의 보다 나은 협조체계의 개발, 소비자의 욕구에 적절히 대응하는 시스템을 학생들에게 교육할 수 있는 프로그램을 개발하였는데 신속대응 시스템을 위한 섬유 패션 스트림간 상품 기획 프로그램을 개발하였다.

• BMB Reports
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• 제34권4호
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• pp.365-370
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• 2001

We constructed a comparative expression system in order to produce recombinant human ferritin homo- and heteropolymers in Escherichia coli. Human ferritin H-(hfH) and L-chain (hfL) genes were expressed without amino acid changes under the control of a tac promoter. Ferritin heteropolymers of varying subunit composition were also produced by combining two different expression systems, a bicistronic expression system and a coplasmid expression system. As a result, recombinant H-chain ferritin and ferritin heteropolymers were catalytically active in forming iron core in vivo. In particular, the ferritin heteropolymer that is composed of 7% H-subunit and 93% L-subunit was capable of forming an iron core of the protein, while the L-chain ferritin homopolymer was inactive in vivo. This result indicates that the two H-subunits (i.e., 7% H-subunit content) are important to keep ferritin active in the cells. In addition, human ferritins were identified as the major iron binding proteins in the transformed cells. Also, the amount of iron bound to the recombinant ferritins was proportional to the H-subunit content in ferritin heteropolymers in vivo.

• Molecules and Cells
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• 제37권8호
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• pp.620-627
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• 2014

We have previously shown that microRNAs (miRNAs) miR-760, miR-186, miR-337-3p, and miR-216b stimulate premature senescence through protein kinase CK2 (CK2) downregulation in human colon cancer cells. Here, we examined whether these four miRNAs are involved in the replicative senescence of human lung fibroblast IMR-90 cells. miR-760 and miR-186 were significantly upregulated in replicatively senescent IMR-90 cells, and their joint action with both miR-337-3p and miR-216b was necessary for efficient downregulation of the ${\alpha}$ subunit of CK2 ($CK2{\alpha}$) in IMR-90 cells. A mutation in any of the four miRNA-binding sequences within the $CK2{\alpha}3^{\prime}$-untranslated region (UTR) indicated that all four miRNAs should simultaneously bind to the target sites for $CK2{\alpha}$ downregulation. The four miRNAs increased senescence-associated ${\beta}$-galactosidase (SA-${\beta}$-gal) staining, p53 and $p21^{Cip1/WAF1}$ expression, and reactive oxygen species (ROS) production in proliferating IMR-90 cells. $CK2{\alpha}$ overexpression almost abolished this event. Taken together, the present results suggest that the upregulation of miR-760 and miR-186 is associated with replicative senescence in human lung fibroblast cells, and their cooperative action with miR-337-3p and miR-216b may induce replicative senescence through $CK2{\alpha}$ downregulation-dependent ROS generation.

• 한국식품과학회지
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• 제25권5호
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• pp.571-575
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• 1993

대두 펩타이드의 표면소수도가 혈청 콜레스테롤의 농도에 미치는 영향을 조사하기 위하여, 대두 단백질(ISP), 카세인(CNP), 이들 단백질을 펩신으로 가수분해하여 pH에 따른 펩타이드 침전 획분들(SHT, SH8, SH6, SH4, CHT, CH6, CH5, CH4)을 흰쥐에 섭취시키고 혈청 콜레스테롤 농도 및 분변 스테로이드이 배설량을 측정하였다. 그리고 각 펩타이드의 표면소수도를 ANS 형광법 및 SDS 결합법으로 측정하여, 이들의 상관관계를 분석한 결과, 펩타이드의 ANS 표면소수도가 높아질수록 분변으로 배설된 스테로이드량은 증가하였으며(r=0.81), 혈청 콜레스테롤 농도는 낮아졌다.(r=-0.868). 그러나 SDS 표면소수도는 그들과 상관관계가 없었다. 또한 대두 단백질은 가수분해에 의하여 ANS 표면소수도가 증가하였다. 이상의 결과는 흰쥐의 담즙염이, 소화중 생성된 높은 표면소수도의 펩타이드와 결합하여 체외로 배출되므로서 대두단백질의 섭취에 의한 혈청 콜레스테롤 농도가 낮아짐을 시사하였다.

• Molecules and Cells
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• 제26권1호
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• pp.61-66
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• 2008

Cyclic AMP receptor protein (CRP) is allosterically activated by cAMP and functions as a global transcription regulator in enteric bacteria. Structural information on CRP in the absence of cAMP (apo-CRP) is essential to fully understand its allosteric behavior. In this study we demonstrated interdomain interactions in apo-CRP, using a comparative thermodynamic approach to the intact protein and its isolated domains, which were prepared either by limited proteolysis or using recombinant DNA. Thermal denaturation of the intact apo-CRP, monitored by differential scanning calorimetry, revealed an apparently single cooperative transition with a slight asymmetry. Combined with circular dichroism and fluorescence analysis, the thermal denaturation of apo-CRP could be interpreted as a coupled process involving two individual transitions, each attributable to a structural domain. When isolated individually, both of the domains exhibited significantly altered thermal behavior, thus pointing to the existence of non-covalent interdomain interactions in the intact apo-CRP. These observations suggest that the allosteric conformational change of CRP upon binding to cAMP is achieved by perturbing or modifying pre-existing interdomain interactions. They also underline the effectiveness of a comparative approach using calorimetric and structural probes for studying the thermodynamics of a protein.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.600-608
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• 2013

Amide analogs of tridecapeptide ${\alpha}$-factor (WHWLQLKPGQPMYCONH$_2$) of Saccharomyces cerevisiae, in which Trp at position 1 and 3 were replaced with other residues, were synthesized to ascertain whether cooperative interactions between two Trp residues occurred upon binding with its receptor. Analogs containing Ala or Aib at position 3 of the peptide $[Ala_3]{\alpha}$-factor amide (2) and $[Aib_3]{\alpha}$-factor amide (5) exhibited greater decreases in bioactivity than analogs with same residue at position one $[Ala^1]{\alpha}$-factor amide (1) and $[Aib^1]{\alpha}$-factor amide (4), reflecting that $Trp^3$ may plays more important role than $Trp^1$ for agonist activity. Analogs containing Ala or Aib in both position one and three 3, 6 exhibited complete loss of bioactivity, emphasizing both the essential role and the combined role of two indole rings for triggering cell signaling. In contrast, double substituted analog with D-Trp in both positions 9 exhibited greater activity than single substituted analog with D-Trp 8 or deleted analog 7, reflecting the combined contribution of two tryptophane residues of ${\alpha}$-factor ligand to activation of Ste2p through interaction with residue $Tyr^{266}$ and importance of the proper parallel orientation of two indole rings for efficient triggering of signal G protein coupled activation. Among ten amide analogs, $[Ala^{1,3}]{\alpha}$-factor amide (3), $[Aib^{1,3}]{\alpha}$-factor amide (6), [D-$Trp^3]{\alpha}$-factor amide (8) and [des-$Trp^1,Phe^3]{\alpha}$-factor amide (10) were found to have antagonistic activity. Analogs 3 and 6 showed greater antagonistic activity than analogs 8 and 10.

• Molecules and Cells
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• 제28권5호
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• pp.479-487
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• 2009

Glutathione reductase (GR) is an enzyme that recycles a key cellular antioxidant molecule glutathione (GSH) from its oxidized form (GSSG) thus maintaining cellular redox homeostasis. A recombinant plasmid to overexpress a GR of Brassica rapa subsp. pekinensis (BrGR) in E. coli BL21 (DE3) was constructed using an expression vector pKM260. Expression of the introduced gene was confirmed by semi-quantitative RT-PCR, immunoblotting and enzyme assays. Purification of the BrGR protein was performed by IMAC method and indicated that the BrGR was a dimmer. The BrGR required NADPH as a cofactor and specific activity was approximately 458 U. The BrGR-expressing E. coli cells showed increased GR activity and tolerance to $H_2O_2$, menadione, and heavy metal ($CdCl_2$, $ZnCl_2$ and $AlCl_2$)-mediated growth inhibition. The ectopic expression of BrGR provoked the co-regulation of a variety of antioxidant enzymes including catalase, superoxide dismutase, glutathione peroxidase, and glucose-6-phosphate dehydrogenase. Consequently, the transformed cells showed decreased hydroperoxide levels when exposed to stressful conditions. A proteomic analysis demonstrated the higher level of induction of proteins involved in glycolysis, detoxification/oxidative stress response, protein folding, transport/binding proteins, cell envelope/porins, and protein translation and modification when exposed to $H_2O_2$ stress. Taken together, these results indicate that the plant GR protein is functional in a cooperative way in the E. coli system to protect cells against oxidative stress.

• International Journal of Industrial Entomology and Biomaterials
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• 제4권2호
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• pp.93-100
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• 2002

Cocoon production, which is a representative of traditional sericulture shifted into silkworm powder production in the spring of 1995. This, infect, signifies the change from the dress-centered textile business to the bio-industry and the functional resource industry. One of the most outstanding shifting is utilization of silkworm larvae for anti-diabetic agent. In Asian countries including Korea, silkworm powder derived from the domestic silkworm (Bombyx mori L.) has long been favored for anti-diabetic agent, but its efficacy was not tested until last decade by modern scientific methods. In this article, we reviewed the major researches on the silkworm powder as a blood glucose-lowering substance. After the beginning test of the efficacy of silkworm powder by a cooperative research between Department of Sericulture and Entomlogy, NIAST, RDA and Kyung Hee University, substantial data have been accumulated so far, In a serial experiment to select best condition, the fifth instar larvae prepared by freeze dry method turned out to have the best blood glucose-lowering effect. In the pharmacological experiment to understand the mechanism of silkworm powder in small intestine, the silkworm powder turned out to inhibit the activity of ${\alpha}$-glucosidase, by competitively binding to $\alpha$-type disaccharides. The animal experiment showed that the extract of silkworm powder prevents a rapid increase of blood glucose level after meal and prevents hunger and law blood glucose level during empty stomach. In the experiment to isolate the major component of silkworm powder, which exerts blood glucose-lowering effect, 1-deoxynojirimy-cin (DNJ) was eventually mass-purified, and it turned out that DNJ isolated from silkworm powder was excellent in its blood glucose-lowering effect. In the experiment to understand the personal difference of the efficacy of the silkworm powder, clinical candidates were divided on the basis of the criterion of traditional Chinese medicine: Tae-Yang, Tae-Um, So-yang, and So-Um. The result showed that silkworm powder has a tendency to reduce blood glucose level at fasting and at 2 hours after meal, and this trend was somewhat obvious in the Tae-Um body type. In summary, we reviewed scientific papers on the efficacy of silkworm powder and its purified DNJ as a blood glucose-lowering agent. These suggest that silkworm powder truly possesses blood glucose-lowering effect as documented in the traditional Chinese medicine, although further researches will be required to develop them as "medical" resource instead of functional food.