• Title/Summary/Keyword: Molecular techniques

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Design of Lactic Acid Bacteria Aiming at Probiotic Culture and Molecular Typing for Phyogenetic Identification (Probiotics용 유산균의 Design과 Molecular Typing에 의한 동정법)

  • Yoon, Sung-Sik
    • Journal of Dairy Science and Biotechnology
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    • v.18 no.1
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    • pp.47-60
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    • 2000
  • Over decades of work, the probiotic research has grown rapidly with a number of new cultures, which is claimed a variety of benefit. However, many of the specific effects attributed to the ingestion of probiotics remain convoluted and scientifically unsubstantiated. Accordingly, the scientific community faces a greater challenge and must objectively seek cause and effect relationships for many potential and currently investigated probiotic species. Rational selection and design of probiotics remains an important challenge and will require a solid information about the physiology and genetics of candidate strains relevant to their intestinal roles, functional activities, and interaction of with other resident micro flora. As far as beneficial culture of lactic acid bacteria (LAB) is concerned, simple, cost-effective, and exact identification of candidate strains is of foremost importance among others. Until recently, the relatedness of bacterial isolates has been determined sorely by testing for one or several phenotyphic markers, using methods such as serotyping, phage-typing, biotyping, and so forth. However, there are problems in the use of many of these phenotype-based methods. In contrast, some of newer molecular typing methods involving the analysis of DNA offer many advantages over traditional techniques. These DNA-based methods have the greater discriminatory power than that of phenotypic procedures. This review focuses on the importance and the basis of molecular typing methods along with some considerations on de-sign and selection of probiotic culture for human consumption.

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Expression and Purification of a Cathelicidin-Derived Antimicrobial Peptide, CRAMP

  • Park Eu-Jin;Chae Young-Kee;Lee Jee-Young;Lee Byoung-Jae;Kim Yang-Mee
    • Journal of Microbiology and Biotechnology
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    • v.16 no.9
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    • pp.1429-1433
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    • 2006
  • Application of recombinant protein production and particularly their isotopic enrichment has stimulated development of a range of novel multidimensional heteronuclear NMR techniques. Peptides in most cases are amenable to assignment and structure determination without the need for isotopic labeling. However, there are many cases where the availability of $^{15}N$ and/or $^{13}C$ labeled peptides is useful to study the structure of peptides with more than 30 residues and the interaction between peptides and membrane. CRAMP (Cathelicidin-Related AntiMicrobial Peptide) was identified from a cDNA clone derived from mouse femoral marrow cells as a member of cathelicidin-derived antimicrobial peptides. CRAMP was successfully expressed as a GST-fused form in E. coli and purified using affinity chromatography and reverse-phase chromatography. The yield of the CRAMP was 1.5 mg/l 1. According to CD spectra, CRAMP adopted ${\alpha}$-helical conformation in membrane-mimetic environments. Isotope labeling of CRAMP is expected to make it possible to study the structure and dynamic properties of CRAMP in various membrane systems.

Methylene Tetrahydrofolate Reductase C677T Mutation and Left Ventricular Hypertrophy in Turkish Patients with Type II Diabetes Mellitus

  • Yilmaz, Hulya;Agachan, Bedia;Ergen, Arzu;Karaalib, Zeynep Ermis;Isbir, Turgay
    • BMB Reports
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    • v.37 no.2
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    • pp.234-238
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    • 2004
  • This study was designed to investigate, in the Turkish population, the association of methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism and left ventricular hypertrophy (LVH) in patients with type II diabetes mellitus. Our study included 249 patients with type II diabetes mellitus (102 men, 147 women) and 214 healthy volunteers as controls (91 men, 123 women). MTHFR C677T genotypes were determined by polymerase chain reaction, restriction fragment length polymorphism techniques. No differences were observed in the distribution of MTHFR genotypes or allele frequencies in the cases versus the controls. The frequency of the MTHFR-mutated allele (T) was 31.7% in the type II diabetes mellitus versus 31.1% of the controls. The homozygous mutation (T/T) in the MTHFR gene was identified in 12% of the type II diabetes mellitus versus 9.3% of the controls. Patients with the TT genotype showed a higher prevalence of LVH when compared to patients with the CC and CT genotypes (p = 0.01). The MTHFR gene C677T mutation may be a possible risk factor for the development of LVH in the type II diabetic patients.

Experimental and ab initio Computational Studies on Dimethyl-(4-{4-{3-methyl-3-phenyl-cyclobutyl)-thiazol-2-yl]-hydrazonomethyl}-phenyl)-amine

  • Yuksektepe, Cigdem;Saracoglu, Hanife;Caliskan, Nezihe;Yilmaz, Ibrahim;Cukurovali, Alaaddin
    • Bulletin of the Korean Chemical Society
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    • v.31 no.12
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    • pp.3553-3560
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    • 2010
  • A new hydrazone derivative compound has been synthesized and characterized by IR, $^1H$-NMR, $^{13}C$-NMR and UV-vis. spectroscopy techniques, elemental analysis and single-crystal X-ray diffraction (XRD). The new compound crystallizes in monoclinic space group C2/c. In addition to the crystal structure from X-ray experiment, the molecular geometry, vibrational frequencies and frontier molecular orbitals analysis of the title compound in the ground state have been calculated by using the HF/6-31G(d, p), B3LYP/6-311G(d, p) and B3LYP/6-31G(d, p) methods. The computed vibrational frequencies are used to determine the types of molecular motions associated with each of the observed experimental bands. To determine conformational flexibility, molecular energy profile of (1) was obtained by semi-empirical (AM1) calculation with respect to a selected degree of torsional freedom, which was varied from $-180^{\circ}$ to $+180^{\circ}$ in steps of $10^{\circ}$. Molecular electrostatic potential of the compound was also performed by the theoretical method.

Quantification of Immunoglobulin G against Trypanosoma cruzi in Individuals with Chronic Chagas Disease Treated with Nifurtimox and Evaluated in Prolonged Follow-Up

  • Munoz, Gabriela;Vergara, Camilo;Martinez, Gabriela;Apt, Werner;Zulantay, Ines
    • Parasites, Hosts and Diseases
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    • v.57 no.1
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    • pp.39-41
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    • 2019
  • In the indeterminate chronic period of Chagas disease (ChD) the treatment has not been conclusive, because the serological negativization requires many years. This study aims to evaluate the efficacy of nifurtimox (NF) in the treatment of chronic ChD in prolonged follow-up by serological techniques of indirect immunofluorescence assay (IFA) and enzyme-linked immunosorbent assay (ELISA) IgG comparing 2 groups of patients, treated and non treated. Mann-Whitney test was performed for ELISA and IFA, with significant difference between the groups (P<0.05). IgG levels were lower in individuals treated compared with untreated patients, indicating chemotherapeutic efficacy in prolonged follow-up.

Pharmacophore Modeling and Molecular Dynamics Simulation to Find the Potent Leads for Aurora Kinase B

  • Sakkiah, Sugunadevi;Thangapandian, Sundarapandian;Kim, Yong-Seong;Lee, Keun-Woo
    • Bulletin of the Korean Chemical Society
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    • v.33 no.3
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    • pp.869-880
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    • 2012
  • Identification of the selective chemical features for Aurora-B inhibitors gained much attraction in drug discovery for the treatment of cancer. Hence to identify the Aurora-B critical features various techniques were utilized such as pharmacophore generation, virtual screening, homology modeling, molecular dynamics, and docking. Top ten hypotheses were generated for Aurora-B and Aurora-A. Among ten hypotheses, HypoB1 and HypoA1 were selected as a best hypothesis for Aurora-B and Aurora-A based on cluster analysis and ranking score, respectively. Test set result revealed that ring aromatic (RA) group in HypoB1 plays an essential role in differentiates Aurora-B from Aurora-A inhibitors. Hence, HypoB1 used as 3D query in virtual screening of databases and the hits were sorted out by applying drug-like properties and molecular docking. The molecular docking result revealed that 15 hits have shown strong hydrogen bond interactions with Ala157, Glu155, and Lys106. Hence, we proposed that HypoB1 might be a reasonable hypothesis to retrieve the structurally diverse and selective leads from various databases to inhibit Aurora-B.

Cancer Metabolism: Strategic Diversion from Targeting Cancer Drivers to Targeting Cancer Suppliers

  • Kim, Soo-Youl
    • Biomolecules & Therapeutics
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    • v.23 no.2
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    • pp.99-109
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    • 2015
  • Drug development groups are close to discovering another pot of gold-a therapeutic target-similar to the success of imatinib (Gleevec) in the field of cancer biology. Modern molecular biology has improved cancer therapy through the identification of more pharmaceutically viable targets, and yet major problems and risks associated with late-phase cancer therapy remain. Presently, a growing number of reports have initiated a discussion about the benefits of metabolic regulation in cancers. The Warburg effect, a great discovery approximately 70 years ago, addresses the "universality" of cancer characteristics. For instance, most cancer cells prefer aerobic glycolysis instead of mitochondrial respiration. Recently, cancer metabolism has been explained not only by metabolites but also through modern molecular and chemical biological techniques. Scientists are seeking context-dependent universality among cancer types according to metabolic and enzymatic pathway signatures. This review presents current cancer metabolism studies and discusses future directions in cancer therapy targeting bio-energetics, bio-anabolism, and autophagy, emphasizing the important contribution of cancer metabolism in cancer therapy.

Computation of viscoelastic flow using neural networks and stochastic simulation

  • Tran-Canh, D.;Tran-Cong, T.
    • Korea-Australia Rheology Journal
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    • v.14 no.4
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    • pp.161-174
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    • 2002
  • A new technique for numerical calculation of viscoelastic flow based on the combination of Neural Net-works (NN) and Brownian Dynamics simulation or Stochastic Simulation Technique (SST) is presented in this paper. This method uses a "universal approximator" based on neural network methodology in combination with the kinetic theory of polymeric liquid in which the stress is computed from the molecular configuration rather than from closed form constitutive equations. Thus the new method obviates not only the need for a rheological constitutive equation to describe the fluid (as in the original Calculation Of Non-Newtonian Flows: Finite Elements St Stochastic Simulation Techniques (CONNFFESSIT) idea) but also any kind of finite element-type discretisation of the domain and its boundary for numerical solution of the governing PDE's. As an illustration of the method, the time development of the planar Couette flow is studied for two molecular kinetic models with finite extensibility, namely the Finitely Extensible Nonlinear Elastic (FENE) and FENE-Peterlin (FENE-P) models.P) models.

Molecular Dynamics Simulation for Compression Test of PMMA Nano Pillars (PMMA 나노 기둥의 압축시험에 대한 분자동역학 해석)

  • Kim, Jung-Yup;Kim, Jae-Hyun;Choi, Byung-Ik
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.502-505
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    • 2007
  • PMMA has been extensively adopted in Nano Imprint Lithography(NIL). PMMA nano-structures experience severe mechanical load and deformation during NIL process, and understanding its mechanical behavior is very important in designing and optimizing NIL process. One of the most promising techniques for characterizing the mechanical behavior of nano structures is nano pillar compression test. In this study, the mechanical behaviors of PMMA pillars during compression test are analyzed using Molecular Dynamics. Two methods for simulation of PMMA nano pillars are proposed. The stress-strain relationship of nano-scale PMMA structure is obtained based on CVFF(Covalent Valence Force Fields) potential and the dependency of the applied strain rate on the stress-strain relationship is analyzed. The obtained stress-strain relationships can be useful in simulating nano-scale PMMA structures using Finite Element Method(FEM) and understanding the experimental results obtained by compression test of PMMA nano pillars.

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Solution State Structure of pA1, the Mimotopic Peptide of Apolipoprotein A-I, by NMR Spectroscopy

  • Kim, Hyo-Joon;Won, Ho-Shik
    • Bulletin of the Korean Chemical Society
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    • v.32 no.9
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    • pp.3425-3428
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    • 2011
  • Apolipoprotein A-I (Apo A-I) is a major component for high density lipoproteins (HDL). A number of mimetic peptides of Apo A-I were screened from the phase-displayed random peptide library by utilizing monoclonal antibodies (A12). Mimetic peptide for A12 epitope against Apo A-I was selected as CPFARLPVEHHDVVGL (pA1). From the BLAST search, the mimetic peptide pA1 had 40% homology with Apo A-I. As a result of the structural determination of this mimotope using homo/hetero nuclear 2D-NMR techniques and NMR-based distance geometry (DG)/molecular dynamic (MD) computations, DG structure had low penalty value of 0.3-0.7 ${\AA}^2$ and the total RMSD was 0.6-1.6 ${\AA}$. The mimotope pA1 exhibited characteristic conformation including a ${\beta}$-turn from Pro[7] to His[11].