Characterization Of Initial Iron Binding Location And The Structure/iron Binding Site On S.cerevisiae Isu And On D.melanogaster Frataxin

Iron-induced free radical damage has been implicated in the pathology of diseases of iron overload such as Friedreich\u27s Ataxia, a genetic disorder characterized by an accumulation of iron in actively metabolizing tissues ultimately leading to cardio- and neuro- degeneration and cell death. It is caused by an inability to synthesize the mitochondrial protein, frataxin. Frataxin has been shown by numerous groups to be a part of the iron-sulfur cluster (ISC) multicomplex, where it functions in the capacity of a potential iron provider and an allosteric modulator of both the cysteine desulfurase and scaffold protein ISU. My research has been focused on studying the interaction between frataxin and ISU, particularly the mechanism of iron binding/ iron acceptance by ISU from frataxin. Using XAS, the Stemmler laboratory characterized the ISU-Fe(ll) bound complex in four orthologs and found that ISU appears to bind iron in a 6 coordinate oxygen/nitrogen ligand environment. The absence of any thiol ligation to metal indicates iron loading onto ISU occurs at a site distinct from its cysteine rich active site. Using site directed mutagenesis, followed by biochemical and biophysical analysis of the mutant proteins in the yeast system, we demonstrate that charged residues E144A and D145A possibly form the interface between iron loaded frataxin and ISU and are involved in initial iron acceptance by ISU. In this thesis, we also describe the crystal structure of Frataxin in D. melanogaster (Dfh). Dfh is well-folded with an α-β sandwich motif comprising two α-helices and six β-strands sandwiched between the two helices like its yeast and human homologs. The Dfh protein does not have a long unstructured N-terminal region like that seen in the yeast and human proteins and it has a considerably longer C-terminal tail; two factors that could contribute to its extraordinary stability. 15N HSQC experiments performed on Dfh in the presence of iron show that the majority of the perturbed residues lie on the α helix-1 and β-strands 1 & 2 region; this is in the region of the conserved acidic patch shared by frataxin proteins indicating an iron binding/ chaperone role for Dfh. As the Dfh protein has been found to be much more stable than its yeast and human counterparts, it would serve as a great starting point to attempt to crystallize the cysteine desulfurase/Isd11/Isu/frataxin (SDUF) proteins in the Drosophila system considering the poor stability of the yeast proteins

Implementasi Manajemen Pengetahuan Dan Dampaknya Terhadap Kinerja Organisasi Pada PT Telekomunikasi Indonesia, Tbk

Economic growth towards globalization that indicated with rapid growth in information technology and communication technology brings impact to human resources development or knowledge based worker to support each organization activity. On the other side, globalization has changed world business community\u27s opinion to be knowledge society and took along the impact to growth of knowledge based competition. PT Telekomunikasi Indonesia, Tbk has applied knowledge management. PTTelekomunikasi Indonesia, Tbk is also one of the company who applied knowledge management well. It can be proved that the company has achieved reward MAKE (Most Admired Knowledge Enterprises) by an consultant organization, Dunamis (the seizer\u27s license). The objectives of this research are (1) To explain the model of knowledge management and organization performance at PT Telekomunikasi Indonesia, Tbk, (2) To explain the managerial implication for PT Telekomunikasi Indonesia, Tbk about knowledge management, (3) To explain employee\u27s perception about realization of knowledge management, (4) To explain organization performance before and after knowledge management applied, (5) To explain the obstacles in implementation of knowledge management and solutions alternative of the impact of knowledge management for increasing organization performance. This research was done at PT Telekomunikasi Indonesia, Tbk. This research uses descriptive analysis and Structural Equation Modelling (SEM), which has a goal to examine between construct independent and dependen also relation between laten variable indicators. The result of this research indicates that organization performance is influenced by knowledge management. The point of contruct coefficient ( ) is 0,62 and t-value 4,22. This point indicates that knowledge management is real significantly and positively influences organization performance. Level of knowledge management implementation is higher shows that level of organization performance is higher too. The impact of knowledge management TELKOM can be shown by product inovation FlexiCombo. Besides that, employee\u27s compentency development can be done by knowledge access through technology. Employee can access it by offline or online so that time efficiency can be attainable

Hyperhomocysteinemia: related genetic diseases and congenital defects, abnormal DNA methylation and newborn screening issues

Homocysteine, a sulfur-containing amino acid derived from the methionine metabolism, is located at the branch point of two pathways of the methionine cycle, i.e. remethylation and transsulfuration. Gene abnormalities in the enzymes catalyzing reactions in both pathways lead to hyperhomocysteinemia. Hyperhomocysteinemia is associated with increased risk for congenital disorders, including neural tube closure defects, heart defects, cleft lip/palate, Down syndrome, and multi-system abnormalities in adults. Since hyperhomocysteinemia is known to affect the extent of DNA methylation, it is likely that abnormal DNA methylation during embryogenesis, may be a pathogenic factor for these congenital disorders. In this review we highlight the importance of homocysteinemia by describing the genes encoding for enzymes of homocysteine metabolism relevant to the clinical practice, especially cystathionine-β-synthase and methylenetetrahydrofolate reductase mutations, and the impairment of related metabolites levels. Moreover, a possible correlation between hyperhomocysteine and congenital disorders through the involvement of abnormal DNA methylation during embryogenesis is discussed. Finally, the relevance of present and future diagnostic tools such as tandem mass spectrometry and next generation sequencing in newborn screening is highlighted

Effects of Chromium Doping on the Electrical Properties of ZnO Nanoparticles

Nanostructured ZnO has gained a considerable amount of attention due to its unique physical and chemical properties and due to its remarkable performance in the fields of optics, photonics and electronics. The scope of this work is to study the Structural, Optical and Electronic properties of Pure Zinc Oxide (ZnO) and Chromium doped Zinc Oxide nanoparticles. These nanoparticles were synthesized by low-temperature precipitation method at various concentrations in the range (Zn1-xCrxO; (x = 0, 0.1& 0.3)). The precursors used were analytical grade Zinc Nitrate Hexahydrate and Chromium Nitrate Nona hydrate. The synthesized nanoparticles were annealed at 400°C. The Structural property of the synthesized nanoparticles was analysed by XRD (X-Ray diffraction) and was confirmed to exhibit a crystalline hexagonal wurtzite structure with an average crystallite size of 55nm. The functional groups were analysed using FTIR (Fourier Transformed Infra-red spectroscopy). The Morphology was analysed by FESEM (Field Emission Scanning Electron Microscope) and a change in morphology from spherical to spindle like structure was observed. The Optical properties were analysed using UV-Vis spectroscopy, the absorption spectrum for electromagnetic spectrum was observed and the changes in the optical band gap of ZnO nanoparticles with Chromium dopant addition were calculated to be in the range of 3.6 eV. The Electrical property of the synthesised nanoparticles was analysed using Electrochemical Impedance Spectroscopy (EIS) and the conductivity was calculated to be in the range of 1.1e-07S/m

Impairment of methyl cycle affects mitochondrial methyl availability and glutathione level in Down's Sindrome

In Down's syndrome there is evidence that increased gene expression coding for specific cystathionine beta-synthase translates directly into biochemical aberrations, which result in a biochemical and metabolic imbalance of the methyl status. This event is destined to impact mitochondrial function since methylation is a necessary event in mitochondria and relies on the availability and uptake of the methyl donor S-adenosylmethionine. Indeed mitochondrial dysfunctions have been widely described in Down's syndrome, but they have never been correlated to a possible mitochondrial methyl unbalance. In the present study we find that the mitochondrial levels of S-adenosylmethionine are reduced in Down's syndrome compared to control cells demonstrating the effect of the methyl unbalance on mitochondria. The possible role of methylation in mitochondria is discussed and some preliminary results on a possible methylation target are presented

Impairment of methyl cycle affects mitochondrial methyl availability and glutathione level in Down's Sindrome

In Down's syndrome there is evidence that increased gene expression coding for specific cystathionine beta-synthase translates directly into biochemical aberrations, which result in a biochemical and metabolic imbalance of the methyl status. This event is destined to impact mitochondrial function since methylation is a necessary event in mitochondria and relies on the availability and uptake of the methyl donor S-adenosylmethionine. Indeed mitochondrial dysfunctions have been widely described in Down's syndrome, but they have never been correlated to a possible mitochondrial methyl unbalance. In the present study we find that the mitochondrial levels of S-adenosylmethionine are reduced in Down's syndrome compared to control cells demonstrating the effect of the methyl unbalance on mitochondria. The possible role of methylation in mitochondria is discussed and some preliminary results on a possible methylation target are presented

Steroid therapy in an alpha-dystroglycanopathy due to GMPPB gene mutations : A case report

Alpha-dystroglycanopathies are a group of progressive and untreatable neuromuscular disorders, due to aberrant alpha-dystroglycan glycosylation. We describe the effects of a short-term cycle of corticosteroid therapy in a 9-year-old boy, affected by an alpha-dystroglycanopathy due to GMPPB gene mutations. The patient was affected by a congenital progressive muscular dystrophy since the first month of life, associated with psychomotor delay, seizures, and congenital bilateral cataracts. Despite physical therapy he had a progressive motor impairment. At the age of 9 years, he was treated with 0.75 mg/kg/day of prednisone for 3 months and showed improvements in muscle strength and function scores and creatine kinase reduction. When steroid therapy was discontinued he showed again clinical and biochemical deterioration. These data suggest that corticosteroid may be considered as a treatment for patients with alpha-dystroglycanopathies due to GMPPB mutations. (C) 2018 Elsevier B.V. All rights reserved.Peer reviewe

Recommendations for Clinical CYP2C19 Genotyping Allele Selection: A Report of the Association for Molecular Pathology

This document was developed by the Pharmacogenetics (PGx) Working Group of the Association for Molecular Pathology Clinical Practice Committee, whose aim is to recommend variants for inclusion in clinical pharmacogenetic testing panels. The goals of the Association for Molecular Pathology PGx Working Group are to define the key attributes of PGx alleles recommended for clinical testing and to define a minimum set of variants that should be included in clinical PGx genotyping assays. These recommendations include a minimum panel of variant alleles (tier 1) and an extended panel of variant alleles (tier 2) that will aid clinical laboratories when designing PGx assays. The Working Group considered variant allele frequencies in different populations and ethnicities, the availability of reference materials, and other technical considerations for PGx testing when developing these recommendations. These CYP2C19 genotyping recommendations are the first of a series of recommendations for PGx testing. These recommendations are not to be interpreted as restrictive, but they are meant to provide a helpful guide

General-relativistic Model of Magnetically Driven Jet

The general scheme for the construction of the general-relativistic model of the magnetically driven jet is suggested. The method is based on the usage of the 3+1 MHD formalism. It is shown that the critical points of the flow and the explicit radial behavior of the physical variables may be derived through the jet ``profile function."Comment: 12 pages, LaTex, no figure