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Articles 1 - 12 of 12

Full-Text Articles in Molecular Biology

Isolation Of Cancer Stem Cells From Adult Glioblastoma Multiforme, Xianpeng Yuan, James Curtin, Yizhi Xiong, Gentao Liu, Sebastian Waschsmann-Hogiu, Daniel Farkas, Keith Black, John Yu Dec 2004

Isolation Of Cancer Stem Cells From Adult Glioblastoma Multiforme, Xianpeng Yuan, James Curtin, Yizhi Xiong, Gentao Liu, Sebastian Waschsmann-Hogiu, Daniel Farkas, Keith Black, John Yu

Articles

Glioblastoma multiforme (GBM) is the most common adult primary brain tumor and is comprised of a heterogeneous population of cells. It is unclear which cells within the tumor mass are responsible for tumor initiation and maintenance. In this study, we report that brain tumor stem cells can be identified from adult GBMs. These tumor stem cells form neurospheres, possess the capacity for self-renewal, express genes associated with neural stem cells (NSCs), generate daughter cells of different phenotypes from one mother cell, and differentiate into the phenotypically diverse populations of cells similar to those present in the initial GBM. Having a …


Rhodobacter Capsulatus Porphobilinogen Synthase, A High Activity Metal Ion Independent Hexamer, David Bollivar Nov 2004

Rhodobacter Capsulatus Porphobilinogen Synthase, A High Activity Metal Ion Independent Hexamer, David Bollivar

Scholarship

No abstract provided.


The Importance Of A Critical Protonation State And The Fate Of The Catalytic Steps In Class A Β-Lactamases And Penicillin-Binding Proteins, Dasantila Golemi-Kotra, Samy O. Meroueh, Choonkeun Kim, Sergei B. Vakulenko, Alexey Bulychev, Ann J. Stemmler, Timothy L. Stemmler, Shahriar Mobashery May 2004

The Importance Of A Critical Protonation State And The Fate Of The Catalytic Steps In Class A Β-Lactamases And Penicillin-Binding Proteins, Dasantila Golemi-Kotra, Samy O. Meroueh, Choonkeun Kim, Sergei B. Vakulenko, Alexey Bulychev, Ann J. Stemmler, Timothy L. Stemmler, Shahriar Mobashery

Biochemistry and Molecular Biology Faculty Publications

b-Lactamases and penicillin-binding proteins are bacterial enzymes involved in antibiotic resistance to b-lactam antibiotics and biosynthetic assembly of cell wall, respectively. Members of these large families of enzymes all experience acylation by their respective substrates at an active-site serine as the first step in their catalytic activities. A Ser-X-X-Lys sequence motif is seen in all these proteins and crystal structures demonstrate that the side chain functions of the serine and lysine are in contact with one another. Three independent methods were used in this report to address the question of the protonation state of this important lysine (Lys73) in the …


Core Concepts In Biochemistry And Molecular Biology In An Integrated Mbbs Curriculum, M P. Iqbal Apr 2004

Core Concepts In Biochemistry And Molecular Biology In An Integrated Mbbs Curriculum, M P. Iqbal

Department of Biological & Biomedical Sciences

No abstract provided.


Photoreactive Bicyclic Amino Acids As Substrates For Mutant Escherichia Coli Phenylalanyl-Trna Synthetases, Thomas Bentin, Ramin Hamzavi, Jahan Salomonsson, Hervé Roy, Michael Ibba, Peter E. Nielsen Mar 2004

Photoreactive Bicyclic Amino Acids As Substrates For Mutant Escherichia Coli Phenylalanyl-Trna Synthetases, Thomas Bentin, Ramin Hamzavi, Jahan Salomonsson, Hervé Roy, Michael Ibba, Peter E. Nielsen

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Unnatural amino acids carrying reactive groups that can be selectively activated under non-invasive biologically benign conditions are of interest in protein engineering as biological tools for the analysis of protein-protein and protein-nucleic acids interactions. The double ring system phenylalanine analogues benzofuranylalanine and benzotriazolylalanine were synthesized, and their photolability was tested by UV irradiation at 254, 320, and 365 nm. Although both showed photo reactivity, benzofuranylalanine appeared as the most promising compound because this amino acid was activated by UVA (long wavelength) irradiation. These amino acids were also tested for in vitro charging of tRNAPhe and for protein mutagenesis via …


Divergence In Non-Cognate Amino Acid Recognition Between Class I And Class Ii Lysyl-Trna Synthetases, Jeffrey D. Levengood, Sandro F. Ataide, Hervé Roy, Michael Ibba Jan 2004

Divergence In Non-Cognate Amino Acid Recognition Between Class I And Class Ii Lysyl-Trna Synthetases, Jeffrey D. Levengood, Sandro F. Ataide, Hervé Roy, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Lysine insertion during coded protein synthesis requires lysyl-tRNALys, which is synthesized by lysyl-tRNA synthetase (LysRS). Two unrelated forms of LysRS are known: LysRS2, which is found in eukaryotes, most bacteria, and a few archaea, and LysRS1, which is found in most archaea and a few bacteria. To compare amino acid recognition between the two forms of LysRS, the effects of l-lysine analogues on aminoacylation were investigated. Both enzymes showed stereospecificity toward the l-enantiomer of lysine and discriminated against noncognate amino acids with different R-groups (arginine, ornithine). Lysine analogues containing substitutions at other positions were generally most effective as …


Actr/Aib1 Functions As An E2f1 Coactivator To Promote Breast Cancer Cell Proliferation And Antiestrogen Resistance, Maggie C. Louie, June X. Zou, Alina Rabinovich, Hong-Wu Chen Jan 2004

Actr/Aib1 Functions As An E2f1 Coactivator To Promote Breast Cancer Cell Proliferation And Antiestrogen Resistance, Maggie C. Louie, June X. Zou, Alina Rabinovich, Hong-Wu Chen

Collected Faculty and Staff Scholarship

Overexpression or amplification of ACTR (also named AIB1, RAC3, p/CIP, TRAM-1, and SRC-3), a member of the p160 family of coactivators for nuclear hormone receptors, has been frequently detected in multiple types of human tumors, including breast cancer. However, its role in cancer cell proliferation and the underlying mechanism are unclear. Here, we show that overexpression of ACTR not only enhances estrogen-stimulated cell proliferation but also, more strikingly, completely negates the cell cycle arrest effect by tamoxifen and pure antiestrogens. Unexpectedly, we found that ACTR directly interacts, through its N-terminal domain, with E2F1 and is recruited to E2F target gene …


Molecular Cloning And Characterization Of Two Mouse Peroxisome Proliferator-Activated Receptor Alpha (Ppara) Regulated Peroxisomal Acyl-Coa Thioesterases., Maria Westin, Mary Hunt, Stefan Alexson Jan 2004

Molecular Cloning And Characterization Of Two Mouse Peroxisome Proliferator-Activated Receptor Alpha (Ppara) Regulated Peroxisomal Acyl-Coa Thioesterases., Maria Westin, Mary Hunt, Stefan Alexson

Articles

Peroxisomes are organelles that function in the b-oxidation of very-long and long-chain acyl-CoAs, bile acid-CoA intermediates, prostaglandins, leukotrienes, thromboxanes, dicarboxylic fatty acids, pristanic acid and xenobiotic carboxylic acids. The very long- and long-chain acyl-CoAs are mainly chain-shortened and then transported to mitochondria for further metabolism. We have now identified and characterized two peroxisomal acyl- CoA thioesterases, named PTE-Ia and PTE-Ic, which hydrolyze acyl-CoAs to the free fatty acid and coenzyme A. PTE-Ia and PTE-Ic show 82% sequence identity at amino acid level and a putative peroxisomal type 1 targeting signal of –AKL was identified at the carboxy-terminal end of both …


Stimulation Of Capacitative Calcium Entry In Hl-60 Cells By Nanosecond Pulsed Electric Fields, Jody A. White, Peter F. Blackmore, Karl H. Schoenbach, Stephen J. Beebe Jan 2004

Stimulation Of Capacitative Calcium Entry In Hl-60 Cells By Nanosecond Pulsed Electric Fields, Jody A. White, Peter F. Blackmore, Karl H. Schoenbach, Stephen J. Beebe

Bioelectrics Publications

Nanosecond pulsed electric fields (nsPEFs) are hypothesized to affect intracellular structures in living cells providing a new means to modulate cell signal transduction mechanisms. The effects of nsPEFs on the release of internal calcium and activation of calcium influx in HL-60 cells were investigated by using real time fluorescent microscopy with Fluo-3 and fluorometry with Fura-2. nsPEFs induced an increase in intracellular calcium levels that was seen in all cells. With pulses of 60 ns duration and electric fields between 4 and 15 kV/cm, intracellular calcium increased 200-700 nM, respectively, above basal levels (similar to100 nM), while the uptake of …


Aminoacyl-Trnas: Setting The Limits Of The Genetic Code, Michael Ibba, Dieter Söll Jan 2004

Aminoacyl-Trnas: Setting The Limits Of The Genetic Code, Michael Ibba, Dieter Söll

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacyl-tRNAs (aa-tRNAs) are simple molecules with a single purpose—to serve as substrates for translation. They consist of mature tRNAs to which an amino acid has been esterified at the 3′-end. The 20 different types of aa-tRNA are made by the 20 different aminoacyl-tRNA synthetases (aaRSs, of which there are two classes), one for each amino acid of the genetic code (Ibba and Söll 2000). This would be fine if it were not for the fact that such a straightforward textbook scenario is not true in a single known living organism. aa-tRNAs lie at the heart of gene expression; they interpret …


Computational Protein Biomarker Prediction: A Case Study For Prostate Cancer, Michael Wagner, Dayanand N. Naik, Alex Pothen, Srinivas Kasukurti, Raghu Ram Devineni, Bao-Ling Adam, O. John Semmes, George L. Wright Jr. Jan 2004

Computational Protein Biomarker Prediction: A Case Study For Prostate Cancer, Michael Wagner, Dayanand N. Naik, Alex Pothen, Srinivas Kasukurti, Raghu Ram Devineni, Bao-Ling Adam, O. John Semmes, George L. Wright Jr.

Mathematics & Statistics Faculty Publications

Background: Recent technological advances in mass spectrometry pose challenges in computational mathematics and statistics to process the mass spectral data into predictive models with clinical and biological significance. We discuss several classification-based approaches to finding protein biomarker candidates using protein profiles obtained via mass spectrometry, and we assess their statistical significance. Our overall goal is to implicate peaks that have a high likelihood of being biologically linked to a given disease state, and thus to narrow the search for biomarker candidates.

Results: Thorough cross-validation studies and randomization tests are performed on a prostate cancer dataset with over 300 patients, obtained …


Dissecting The Loci Of Low-Level Quinine Resistance In Malaria Parasites, Michael T. Ferdig, Roland A. Cooper, Jianbing Mu, Bingbing Deng, Deirdre A. Joy, Xin-Zhuan Su, Thomas E. Wellems Jan 2004

Dissecting The Loci Of Low-Level Quinine Resistance In Malaria Parasites, Michael T. Ferdig, Roland A. Cooper, Jianbing Mu, Bingbing Deng, Deirdre A. Joy, Xin-Zhuan Su, Thomas E. Wellems

Biological Sciences Faculty Publications

Quinine (QN) remains effective against Plasmodium falciparum, but its decreasing efficacy is documented from different continents. Multiple genes are likely to contribute to the evolution of QN resistance. To locate genes contributing to QN response variation, we have searched a P. falciparum genetic cross for quantitative trait loci (QTL). Results identify additive QTL in segments of chromosomes (Chrs) 13, 7 and 5, and pairwise effects from two additional loci of Chrs 9 and 6 that interact, respectively, with the QTL of Chrs 13 and 7. The mapped segments of Chrs 7 and 5 contain pfcrt, the determinant of …