• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1823-1828
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• 2013

Tetraoxanes (1,2,4,5-tetraoxanes) have been reported to exhibit potent antimalarial activity. In the present study, the three dimensional-quantitative structure activity relationship (3D-QSAR) studies were performed on a series of tetraoxanes derivatives using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) techniques. The best predictive CoMFA model with atom fit alignment resulted in cross-validated coefficient ($q^2$) value of 0.719, non-cross-validated coefficient ($r^2$) value of 0.855 with standard error of estimate (SEE) 0.335. Similarly, the best predictive CoMSIA model was derived with $q^2$ of 0.739, $r^2$ of 0.847 and SEE of 0.344. The generated models were externally validated using test sets. The final QSAR models as well as the information gathered from 3D contour maps should be useful for the design of novel tetraoxanes having improved antimalarial activity.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.77-83
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• 1999

Molecular biological techniques that recently developed, have made it possible to realize some of new attempts in the research field of rumen microbiology. Those are 1) cloning of genes from rumen microorganisms mainly in E. coli, 2) transformation of rumen bacteria and 3) ecological analysis with nonculturing methods. Most of the cloned genes are for polysaccharidase enzymes such as endoglucanase, xylanase, amylase, chitinase and others, and the cloning rendered gene structural analyses by sequencing and also characterization of the translated products through easier purification. Electrotransformation of Butyrivibrio fibrisolvens and Prevotella ruminicola have been made toward the direction for obtaining more fibrolytic, acid-tolerant, depoisoning or essential amino acids-producing rumen bacterium. These primarily required stable and efficient gene transfer systems. Some vectors, constructed from native plasmids of rumen bacteria, are now available for successful gene introduction and expression in those rumen bacterial species. Probing and PCR-based methodologies have also been developed for detecting specific bacterial species and even strains. These are much due to accumulation of rRNA gene sequences of rumen microbes in databases. Although optimized analytical conditions are essential to reliable and reproducible estimation of the targeted microbes, the methods permit long term storage of frozen samples, providing us ease in analytical work as compared with a traditional method based on culturing. Moreover, the methods seem to be promissing for obtaining taxonomic and evolutionary information on all the rumen microbes, whether they are culturable or not.

• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.97-102
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• 2009

Translocation of biopolymers such as DNA and RNA through a nano-pore is an important process in biotechnology applications. The translocation process of a biopolymer through an artificial nano-pore in the presence of a fluid solvent is simulated. The polymer motion is simulated by Langevin molecular dynamics (MD) techniques while the solvent dynamics are taken into account by lattice-Boltzmann method (LBM). The hydrodynamic interactions are considered explicitly by coupling the polymer and solvent through the frictional and the random forces. From simulation results we found that the hydrodynamic interactions between polymer and solvent speed-up the translocation process. The translocation time ${\tao}_T$ scales with the chain length N as ${{\tau}_T}^{\propto}N^{\alpha}$. The value of scaling exponents($\alpha$) obtained from our simulations are $1.29{\pm}0.03$ and $1.41{\pm}0.03$, with and without hydrodynamic interactions, respectively. Our simulation results are in good agreement with the experimentally observed value of $\alpha$, which is equal to $1.27{\pm}0.03$, particularly when hydrodynamic interaction effects are taken into account.

• Journal of Environmental Science International
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• v.15 no.2
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• pp.177-183
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• 2006

The hydrolytic kinetics of biodegradable poly(l-lactide) (PLLA) have been studied by using two model systems, solution-grown single crystal (SC) and Langmuir monolayer techniques, for elucidating the mechanism for both alkaline and enzymatic degradations. The present study investigated the parameters such as degradation medium and time. The Langmuir mono layers of PLLA showed faster rates of hydrolysis when they were exposed to a basic subphase rather than they did when exposed to neutral subphase. Both degradation mediums had moderate concentrations to show a maximized activity, depending on their sizes. An alkaline degradation of SCs of PLLA showed the decrease of molecular weight of the remained crystals due to the erosion of chain-folding surface. However, the enzymatic degradation of SCs of PLLA occurred in the crystal edges thus the molecular weight of remained crystals was not changed. This behavior might be attributed to the size of enzymes which is much larger than that of alkaline ions; that is, the enzymes need larger contact area with monolayers to be activated.

• BMB Reports
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• v.43 no.2
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• pp.79-90
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• 2010

Mouse models are crucial for the functional annotation of human genome. Gene modification techniques including gene targeting and gene trap in mouse have provided powerful tools in the form of genetically engineered mice (GEM) for understanding the molecular pathogenesis of human diseases. Several international consortium and programs are under way to deliver mutations in every gene in mouse genome. The information from studying these GEM can be shared through international collaboration. However, there are many limitations in utility because not all human genes are knocked out in mouse and they are not yet phenotypically characterized by standardized ways which is required for sharing and evaluating data from GEM. The recent improvement in mouse genetics has now moved the bottleneck in mouse functional genomics from the production of GEM to the systematic mouse phenotype analysis of GEM. Enhanced, reproducible and comprehensive mouse phenotype analysis has thus emerged as a prerequisite for effectively engaging the phenotyping bottleneck. In this review, current information on systematic mouse phenotype analysis and an issue-oriented perspective will be provided.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.5 no.2
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• pp.145-151
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• 2019

Fluorine-18 is considered to be the radionuclide of choice for positron emission tomography (PET). Thus, the development of small molecule-based radiopharmaceuticals for use in diagnostic imaging relies heavily on efficient radiofluorination techniques. Until the early 2000s, diaryliodonium salts and aryliodonium ylides were widely employed as labeling precursors to yield aromatic PET radiotracers with cyclotron-produced [¹⁸F]fluoride ion. Rapid recent progress in the development of efficient borylation methods has led to a paradigm shift in ¹⁸F-labeling methods. In addition, deoxyfluorination has attracted a great deal of interest as an alternative approach to aryl ring activation with ¹⁸F^-. In this review, methods for radiolabel development are discussed with a specific focus on the progress made in the last 5 years. Other interesting ¹⁸F-based protocols are also briefly introduced. New methods for exploiting ¹⁸F^- are expected to increase the number of ¹⁸F-labeling methods, to allow applications in a range of chemical environments.

• Journal of Applied Biological Chemistry
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• v.53 no.3
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• pp.121-125
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• 2010

In the past 10 years, a lot of plant circadian rhythm researches have published in molecular biology and biochemistry. We discussed with published molecular studies of circadian clock and rhythmic genes in Arabidopsis, rice and algae. However past this studies are not sufficient to explain the whole rhythmic metabolism. Recently many researchers have concerned post-transcriptional, translational and post-translational modification of rhythmic proteins. From the view point of the high-throughput study, we could suggest the proteomic analysis with 2-DE gel electrophoresis and MS/MS techniques for the identification of modified proteins.

• BMB Reports
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• v.43 no.10
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• pp.643-648
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• 2010

Sir William Osler (1849-1919) recognized that "variability is the law of life, and as no two faces are the same, so no two bodies are alike, and no two individuals react alike and behave alike under the abnormal conditions we know as disease". Accordingly, the traditional methods of medicine are not always best for all patients. Over the last decade, the study of genomes and their derivatives (RNA, protein and metabolite) has rapidly advanced to the point that genomic research now serves as the basis for many medical decisions and public health initiatives. Genomic tools such as sequence variation, transcription and, more recently, personal genome sequencing enable the precise prediction and treatment of disease. At present, DNA-based risk assessment for common complex diseases, application of molecular signatures for cancer diagnosis and prognosis, genome-guided therapy, and dose selection of therapeutic drugs are the important issues in personalized medicine. In order to make personalized medicine effective, these genomic techniques must be standardized and integrated into health systems and clinical workflow. In addition, full application of personalized or genomic medicine requires dramatic changes in regulatory and reimbursement policies as well as legislative protection related to privacy. This review aims to provide a general overview of these topics in the field of personalized medicine.

• BMB Reports
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• v.32 no.5
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• pp.497-501
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• 1999

Biotinylation of recombinant proteins is a powerful tool for the detection and analysis of proteins of interest in a large variety of assay systems. The recent development of in vivo biotinylation techniques in E. coli has opened new possibilities for the production of site-specifically biotinylated proteins without the need for further manipulation after the isolation of the recombinantly expressed proteins. In the present study, a novel vector set was generated which allows the convenient cloning and expression of proteins of interest fused with an N-terminal in vivo biotinylated thioredoxin (TRX) protein. These vectors were derived from the previously reported pBIOTRX vector into which was incorporated part of the pBluescript II+phagemid multiple cloning site (MCS), amplified by PCR using a pair of sophisticated oligonucleotide primers. The functionality of these novel vectors was examined in this system by recombinant expression of rat transforming growth factor-$\beta$. Western-blot analysis using TRX-specific antibodies or peroxidase-conjugated streptavidin confirmed the successful induction of the fusion protein and the in vivo conjugation of biotin molecules, respectively. The convenience of molecular subcloning provided by the MCS and the effective in vivo biotinylation of proteins of interest makes this novel vector set an interesting alternative for the production of biotinylated proteins.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.337-341
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• 2001

To isolate antifungal substances from Korean radish (Raphanus Sativus L.) seeds, various purification techniques such as DE52 cellulose anion exchange, SP-Sephadex C-25 cation exchange, and Sephadex G-50 gel filtration chromatographies were used. The molecular masses of two purified R. sativus antifungal proteins (RAPs) were estimated to be about 6.1 kDa (RAP-1) and 6.2 kDa (RAP-2) by SDS-PAGE, and 5.8 kDa(RAP-1) and 6.2 kDa (RAP-2 by a gel filtration chromatography, respectively. Purified proteins RAP-1 and 2 clearly exhibited different growth inhibitory activities against other microorganisms like Candida albicans and Saccharomyces cerevisiae. Although they have similar molecular masses, both RAP-1 and 2 proteins are not identical because their microbial inhibitory actions were different. Therefore, RAP-1 could be a new antifungal protein when compared with the antifungal activities of 2S albumins, Rs-AFPs, Mj-AMPs, chitinase, glucanase, permatin, and ribosome inactivating proteins, all of which are anifungal proteins of plants.