• 충청수학회지
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• 제31권2호
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• pp.239-246
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• 2018

In this paper, we define a concept of weak co-T-cofibration which is a generalization of weak H'-cofibration, and study some properties of weak co-T-cofibration and relations between the weak co-T-cofibration and the homology decomposition for a cofibration.

• 대한기계학회논문집A
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• 제20권9호
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• pp.2800-2811
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• 1996

The deformation of a structure shall be called homologous, if a given geometrical relation holds, for a given number of structural points, before, during, and after the deformation. Some researchers have utilized the idea on structural design with finite element method. The approaches use the decomposition of the FEM equation or equality of eqality equations to obtain homologous deformation. However, weight reduction and response constraints such as stress, displacement or natural frequency cannot be considered by those theories. An optimization method solving the above problems is suggested to gain homologous deformation. Homology constraints can be considered under multiple loadindg conditions as well as a single loading condition. Homology index is defined for the multiple loading conditions Examples are solved to present the performances of the method.

• Journal of Microbiology and Biotechnology
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• 제34권9호
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• pp.1867-1875
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• 2024

Identification of the biochemical metabolic pathway for lignin decomposition and the responsible degradative enzymes is needed for the effective biotechnological valorization of lignin to renewable chemical products. In this study, we investigated the decomposition of kraft lignin by the soil bacterium Pseudomonas kribbensis CHA-19, a strain that can utilize kraft lignin and its main degradation metabolite, vanillic acid, as growth substrates. Gel permeation chromatography revealed that CHA-19 decomposed polymeric lignin and degraded dehydrodivanillin (a representative lignin model compound); however, the degradative enzyme(s) and mechanism were not identified. Quantitative polymerase chain reaction with mRNAs from CHA-19 cells induced in the presence of lignin showed that the putative genes coding for two laccase-like multicopper oxidases (LMCOs) and three dye-decolorizing peroxidases (DyPs) were upregulated by 2.0- to 7.9-fold compared with glucose-induced cells, which indicates possible cooperation with multiple enzymes for lignin decomposition. Computational homology analysis of the protein sequences of LMCOs and DyPs also predicted their roles in lignin decomposition. Based on the above data, CHA-19 appears to initiate oxidative lignin decomposition using multifunctional LMCOs and DyPs, producing smaller metabolites such as vanillic acid, which is further degraded via ortho- and meta-ring cleavage pathways. This study not only helps to better understand the role of bacteria in lignin decomposition and thus in terrestrial ecosystems, but also expands the biocatalytic toolbox with new bacterial cells and their degradative enzymes for lignin valorization.

• 대한기계학회논문집A
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• 제20권3호
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• pp.872-881
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• 1996

The concept of homology design has been devised for the application to large telescope structure by S.v.Hoerner. It is defined that the deformation of a structure shall be called homologous, if a given geometrical relation holds, for a given number of structural points, before, during, and after the deformation. Recently, the need of homology design in the structural design has been increase due to the required precision in the structure. Some researchers have utilized the theory on the structural design with finite element method in the late 1980s In the present investigation, a simple method using geometrical equality constraints is suggested to gain homologous deformation. The previous method is improved in that the decomposition of FEM eqation, which is very expensive, is not necessary. The basic formulations of the homology design with the optimization concept are described and several practical examples are solved to verify the usefulness and validity. Especially, a back-up structure of a satellite antenna is designed by the suggested method. The results are compared with those of existing researches.

• Journal of Microbiology and Biotechnology
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• 제23권12호
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• pp.1699-1707
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• 2013

During the fermentative production of 1,3-propanediol under high substrate concentrations, accumulation of intracellular 3-hydroxypropionaldehyde will cause premature cessation of cell growth and glycerol consumption. Discovery of oxidoreductases that can convert 3-hydroxypropionaldehyde to 1,3-propanediol using NADPH as cofactor could serve as a solution to this problem. In this paper, the yqhD gene from Klebsiella pneumoniae DSM2026, which was found encoding an aldehyde reductase (KpAR), was cloned and characterized. KpAR showed broad substrate specificity under physiological direction, whereas no catalytic activity was detected in the oxidation direction, and both NADPH and NADH can be utilized as cofactors. The cofactor binding mechanism was then investigated employing homology modeling and molecular dynamics simulations. Hydrogen-bond analysis showed that the hydrogen-bond interactions between KpAR and NADPH are much stronger than that for NADH. Free-energy decomposition dedicated that residues Gly37 to Val41 contribute most to the cofactor preference through polar interactions. In conclusion, this work provides a novel aldehyde reductase that has potential applications in the development of novel genetically engineered strains in the 1,3-propanediol industry, and gives a better understanding of the mechanisms involved in cofactor binding.

• 생명과학회지
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• 제15권5호
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• pp.743-748
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• 2005

Histamine은 적색육 어류의 histidine이 어육 중의 Morganella morganii, Hafnia alvei 및 Klebsiella pneumoniae와 같은 부패세균에 의해 탈탄산 되어 초기에 형성되는 것으로 allergy성 식중독을 일으킬 수 있다. 이는 적색육 어류인 고등어의 선도저하 시에 많이 생성된다. 그리고 부패 후기에는 histamine을 분해하는 세균도 존재하는 것으로 알려져 있다. 그러므로, histamine 식중독의 잠재력을 지닌 자반고등어로 인한 식중독 사고 예방과 그 위생 대책을 수립하는데 필요한 자료를 얻고자 자반고등어에서 histamine 분해능을 가진 균을 분리, 동정하였다. 시료는 대형마트에서 시판되는 상태로 구입하였다. 질소원과 탄소원으로써 histamine만을 첨가한 제한배지를 사용하여 histamine 분해능을 가진 균을 분리하였다. 그리고 Cram staining, oxidase, catalase, citrate, TSI test, $H_{2}S$ reaction 및 indole 생성 등의 기본적인 생화학적 동정시험을 거쳐 10종의 시험균주를 선택하였다. 이 균주들을 16SrRNA gene 염기서열 비교에 의한 계통발생학적 분석을 이용하여 동정 하였다. 그 결과, Pseudomonas putida strain RA2, Halomonas marina, Uncultured Arctic sea ice bacterium clone ARKXV1/2-136, Halomonas venusta, Psychrobacter sp. HS5323, Pseudemonas putida KT2440, Rhodococcus erythropolis, Klebsiella terrigena (Raoultella terrigena), Alteromonadaceae bacterium T1, Shewanella massilia의 10종이 모두 동정 되 었으며, 각각 $100\%,{\;}100\%,{\;}99\%,{\;}99\%,{\;}99\%,{\;}99\%,{\;}100\%,{\;}95\%,{\;}99\%,{\;}100\%$의 상동성을 보였다. Histamine분해능의 존재를 탁도측정법과 효소법에 의해 확인한 결과, 분리된 10종 모두의 histamine 분해능이 재확인 되었고, 그 중 Shewanella massilia가 최대의 histamine 분해능을 보이는 것으로 확인되었다. 이 결과로 자반고등어 시판 제품에는 다수의 histamine 분해 세균이 존재하는 것을 확인할 수 있었으며, 이 세균을 활용한다면 식품 내 존재하는 histamine을 효과적으로 분해할 수 있을 것이라 예상된다.