• Title/Summary/Keyword: molecular methods

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3D-QSAR Analysis and Molecular Docking of Thiosemicarbazone Analogues as a Potent Tyrosinase Inhibitor

  • Park, Joon-Ho;Sung, Nack-Do
    • Bulletin of the Korean Chemical Society
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    • v.32 no.4
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    • pp.1241-1248
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    • 2011
  • Three dimensional quantitative structure-activity relationships (3D-QSARs) between new thiosemicarbazone analogues (1-31) as a substrate molecule and their inhibitory activity against tyrosinase as a receptor were performed and discussed quantitatively using CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indices analysis) methods. According to the optimized CoMSIA 2 model obtained from the above procedure, inhibitory activities were mainly dependent upon H-bond acceptor favored field (36.5%) of substrate molecules. The optimized CoMSIA 2 model, with the sensitivity of the perturbation and the prediction, produced by a progressive scrambling analysis was not dependent on chance correlation. From molecular docking studies, it is supposed that the inhibitory activation of the substrate molecules against tyrosinase (PDB code: 1WX2) would not take place via uncompetitive inhibition forming a chelate between copper atoms in the active site of tyrosinase and thiosemicarbazone moieties of the substrate molecules, but via competitive inhibition based on H-bonding.

AdoMet Derivatives Induce the Production of Actinorhodin in Streptomyces coelicolor

  • Lee Yu-Kyung;Young Jung-Mo;Kwon Hyung-Jin;Suh Joo-Won;Kim Jin-Young;Chong You-Hoon;Lim Yoong-Ho
    • Journal of Microbiology and Biotechnology
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    • v.16 no.6
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    • pp.965-968
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    • 2006
  • Exogenous S-adenosyl-L-methionine (AdoMet) enhances the production of actinorhodin in Streptomyces coelicolor. Thirty compounds related structurally with AdoMet were tested for their actinorhodin production. The relationships between the structures of the compounds tested and their actinorhodin production were analyzed using computational methods, and the molecules containing both bulky substituents at the C6 position of adenine and the long 5'-alkyl chain of adenosine were predicted to show high actinorhodin production.

On the continuum formulation for modeling DNA loop formation

  • Teng, Hailong;Lee, Chung-Hao;Chen, Jiun-Shyan
    • Interaction and multiscale mechanics
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    • v.4 no.3
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    • pp.219-237
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    • 2011
  • Recent advances in scientific computing enable the full atomistic simulation of DNA molecules. However, there exists length and time scale limitations in molecular dynamics (MD) simulation for large DNA molecules. In this work, a two-level homogenization of DNA molecules is proposed. A wavelet projection method is first introduced to form a coarse-grained DNA molecule represented with superatoms. The coarsened MD model offers a simplified molecular structure for the continuum description of DNA molecules. The coarsened DNA molecular structure is then homogenized into a three-dimensional beam with embedded molecular properties. The methods to determine the elasticity constants in the continuum model are also presented. The proposed continuum model is adopted for the study of mechanical behavior of DNA loop.

MR Contrast Agents and Molecular Imaging (MR조영제와 분자영상)

  • Moon, Woo-Kyung
    • The Korean Journal of Nuclear Medicine
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    • v.38 no.2
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    • pp.205-208
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    • 2004
  • The two major classes of magnetic resonance (MR) contrast agents are paramagnetic contrast agents, usually based on chelates of gadolinium generating T1 positive signal enhancement, and super-paramagnetic contrast agents that use mono- or polycrystalline iron oxide to generate strong T2 negative contrast in MR images. These paramagnetic or super-paramagnetic complexes are used to develop new contrast agents that can target the specific molecular marker of the cells or tan be activated to report on the physiological status or metabolic activity of biological systems. In molecular imaging science, MR imaging has emerged as a leading technique because it provides high-resolution three-dimension maps of the living subject. The future of molecular MR imaging is promising as advancements in hardware, contrast agents, and image acquisition methods coalesce to bring high resolution in vivo imaging to the biochemical sciences and to patient care.

Cyanobacterial Taxonomy: Current Problems and Prospects for the Integration of Traditional and Molecular Approaches

  • Komarek, Jiri
    • ALGAE
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    • v.21 no.4
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    • pp.349-375
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    • 2006
  • The application of modern ecological, ultrastructural and molecular methods, aided by the cultivation of numerous cyanobacterial morphotypes, has substantially changed our knowledge of these organisms. It has led to major advances in cyanobacterial taxonomy and criteria for their phylogenetic classification. Molecular data provide basic criteria for cyanobacterial taxonomy; however, a correct phylogenetic system cannot be constructed without combining genetic data with knowledge from the previous 150 years research of cyanobacterial diversity. Thus, studies of morphological variation in nature, and modern morphological, ultrastructural, ecophysiological and biochemical characters need to be combined in a “polyphasic” approach. Taxonomic concepts for generic and infrageneric ranks are re-evaluated in light of combined phenotypic and molecular criteria. Despite their usefulness in experimental studies, the limitations of using strains from culture collections for systematic and nomenclatural purposes is highlighted. The need for a continual revision of strain identification and proper nomenclatural practice associated with either the bacteriological or botanical codes is emphasized. Recent advances in taxonomy are highlighted in the context of prospects for understanding cyanobacterial diversity from natural habitats, and the evolutionary and adaptational processes that cyanobacteria undergo.

Positron emission tomography and magnetic resonance imaging

  • Yim, Min Su;Ryu, Eun Kyoung
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.2 no.1
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    • pp.3-8
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    • 2016
  • Molecular imaging technologies have been used to provide a new pathway for therapies and diagnosis of human disease. Especially, imaging probes have been much development in the molecular imaging field. Combining imaging probes for positron emission tomography (PET) and magnetic resonance imaging (MRI) have suggested the potential of multiple methods in living body. This review discusses the cancer or lymph node-targeting probes that are suitable for PET/MRI based diagnosis.

Enhanced Inter-Symbol Interference Cancellation Scheme for Diffusion Based Molecular Communication using Maximum Likelihood Estimation

  • Raut, Prachi;Sarwade, Nisha
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.10
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    • pp.5035-5048
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    • 2016
  • Nano scale networks are futuristic networks deemed as enablers for the Internet of Nano Things, Body area nano networks, target tracking, anomaly/ abnormality detection at molecular level and neuronal therapy / drug delivery applications. Molecular communication is considered the most compatible communication technology for nano devices. However, connectivity in such networks is very low due to inter-symbol interference (ISI). Few research papers have addressed the issue of ISI mitigation in molecular communication. However, many of these methods are not adaptive to dynamic environmental conditions. This paper presents an enhancement over original Memory-1 ISI cancellation scheme using maximum likelihood estimation of a channel parameter (λ) to make it adaptable to variable channel conditions. Results of the Monte Carlo simulation show that, the connectivity (Pconn) improves by 28% for given simulation parameters and environmental conditions by using enhanced Memory-1 cancellation method. Moreover, this ISI mitigation method allows reduction in symbol time (Ts) up to 50 seconds i.e. an improvement of 75% is achieved.

Radioiodination strategies for carborane compounds

  • Rajkumar Subramani;Abhinav Bhise;Jeongsoo Yoo
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.8 no.1
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    • pp.39-44
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    • 2022
  • The development of methods for the inert and stable radiohalogenation of targeted radiopharmaceuticals is a prerequisite for real-time diagnosis and therapy using radiohalogenated radiopharmaceuticals. Radiohalogenated carboranes demonstrate superior stability in vivo and versatile applications compared with directly labeled tyrosine analogues or synthetically modified organic compounds. Herein, we focus on the most common approaches for the radioiodination (123l, 124l, 125l, and 131l) of carborane derivatives.