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Articles 14011 - 14040 of 15505
Full-Text Articles in Entire DC Network
Cell Adhesion On Surfaces Of Varying Topographies, Ilsoon Lee, Christina Chan, Srivatsan Kidambi
Cell Adhesion On Surfaces Of Varying Topographies, Ilsoon Lee, Christina Chan, Srivatsan Kidambi
Department of Chemical and Biomolecular Engineering: Faculty Publications
Micro-topography of a surface influences cell adhesion and proliferation. To improve adhesion, polyelectrolyte multilayers (PEMs) are built on patterned support layers to increase surface wettability, thereby improving attachment and spreading of the cells. Physical parameters, such as pattern size and pitch, in part, regulate cell adhesion and proliferation. Varying the surface topography provides a method to influence cell attachment and proliferation for tissue engineering applications.
Web-Based Applications For Building, Managing And Analysing Kinetic Models Of Biological Systems, Dong-Yup Lee, Rajib Saha, Faraaz Noor Khan Yusufi, Wonjun Park, Iftekhara. Karimi
Web-Based Applications For Building, Managing And Analysing Kinetic Models Of Biological Systems, Dong-Yup Lee, Rajib Saha, Faraaz Noor Khan Yusufi, Wonjun Park, Iftekhara. Karimi
Department of Chemical and Biomolecular Engineering: Faculty Publications
Mathematical modelling and computational analysis play an essential role in improving our capability to elucidate the functions and characteristics of complex biological systems such as metabolic, regulatory and cell signalling pathways. The modelling and concomitant simulation render it possible to predict the cellular behaviour of systems under various genetically and/or environmentally perturbed conditions. This motivates systems biologists/bioengineers/ bioinformaticians to develop new tools and applications, allowing non-experts to easily conduct such modelling and analysis.However, among a multitude of systems biology tools developed to date, only a handful of projects have adopted a web-based approach to kinetic modelling. In this report, we …
Whole-Plant Mineral Partitioning Throughout The Life Cycle In Arabidopsis Thaliana Ecotypes Columbia, Landsberg Erecta, Cape Verde Islands, And The Mutant Line Ysl1ysl3, Brian M. Waters, Michael A. Grusak
Whole-Plant Mineral Partitioning Throughout The Life Cycle In Arabidopsis Thaliana Ecotypes Columbia, Landsberg Erecta, Cape Verde Islands, And The Mutant Line Ysl1ysl3, Brian M. Waters, Michael A. Grusak
Department of Agronomy and Horticulture: Faculty Publications
Minimal information exists on whole-plant dynamics of mineral flow through Arabidopsis thaliana or on the source tissues responsible for mineral export to developing seeds. Understanding these phenomena in a model plant could help in the development of nutritionally enhanced crop cultivars. A whole-plant partitioning study, using sequential harvests, was conducted to characterize growth and mineral concentrations and contents of rosettes, cauline leaves, stems, immature fruit, mature fruit hulls, and seeds of three WT lines (Col-0, Ler, and Cvi) and one mutant line (Col-0::ysl1ysl3). Shoot mineral content increased throughout the life cycle for all minerals, although tissue-specific …
Registration Of ‘Darrell’ Wheat, A. M. H. Ibrahim, S. D. Haley, P. S. Baenziger, Y. Jin, M. A. C. Langham, J. Rickertsen, S. Kalsbeck, R. Little, J. Ingemansen, O. K. Chung, B. W. Seabourn, G. H. Bai, Ming-Shun Chen, D. V. Mcvey
Registration Of ‘Darrell’ Wheat, A. M. H. Ibrahim, S. D. Haley, P. S. Baenziger, Y. Jin, M. A. C. Langham, J. Rickertsen, S. Kalsbeck, R. Little, J. Ingemansen, O. K. Chung, B. W. Seabourn, G. H. Bai, Ming-Shun Chen, D. V. Mcvey
Department of Agronomy and Horticulture: Faculty Publications
‘Darrell’ (Reg. No. CV-1024, PI 644224) hard red winter wheat (Triticum aestivum L.) was developed by the South Dakota State University–Agricultural Experiment Station and released in 2006 to seed producers by the South Dakota State University–Agricultural Experiment Station and the University of Nebraska Agricultural Experiment Station. Darrell was selected from the cross 2076-W12-11/‘Karl 92’ (PI 564245)//NE89526. NE89526 is an experimental line from the University of Nebraska with the pedigree ‘Lancota’ (CI 17389) selection/’Siouxland’ (PI 483469)//TX792729. 2076-W12-11 is an unreleased experimental line that originated from a population with an unidentified pedigree. Darrell was selected as an F3:4 line in 1998 …
Pathogen Best Management Practices (Bmps), Richard K. Koelsch
Pathogen Best Management Practices (Bmps), Richard K. Koelsch
Department of Agricultural and Biological Systems Engineering: Presentations and White Papers
Management practices targeting pathogens focus on establishing multiple barriers between the pathogen source and water, with each barrier designed to lessen the risk of pathogens. The “Agricultural Environmental Management” program developed at Cornell University for dairy producers in New York watersheds promotes a four-barrier approach.
Alkaline Pretreatment Of Coastal Bermudagrass For Bioethanol Production, Ziyu Wang, Deepak R. Keshwani, Arthur P. Redding, Jay J. Cheng
Alkaline Pretreatment Of Coastal Bermudagrass For Bioethanol Production, Ziyu Wang, Deepak R. Keshwani, Arthur P. Redding, Jay J. Cheng
Department of Agricultural and Biological Systems Engineering: Presentations and White Papers
Lignocellulosic materials are regarded as an alternative energy source for bioethanol production to reduce our reliance on fossil fuels. Pretreatment is important for improving the enzymatic digestibility of lignocelluloses to increase the yield of fermentable sugars. Alkaline (sodium hydroxide and lime (calcium hydroxide)) pretreatment of coastal bermudagrass for enhanced reducing sugars recovery was investigated in this study. The effect of NaOH pretreatment at 121°C using 1%, 2% and 3% (w/v) NaOH for 15, 30, 60 and 90 minutes was evaluated first. Lower NaOH concentrations (0.5% and 0.75%) and lower temperatures (50, 80 and 100°C) were then examined. Lime (0.1 g …
Preparation And Characterization Of Tapioca Starch-Poly(Lactic Acid)-Cloisite Na+ Nanocomposite Foams, Siew-Yoong Lee, Milford Hanna
Preparation And Characterization Of Tapioca Starch-Poly(Lactic Acid)-Cloisite Na+ Nanocomposite Foams, Siew-Yoong Lee, Milford Hanna
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Tapioca starch, poly(lactic acid), and Cloisite NA+ nanocomposite foams, with four clay contents (1, 3, 5, 7, wt %), were prepared by melt-intercalation method. Selected structural, thermal, physical, and mechanical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy, differential scanning calorimetry, and an Instron universal testing machine, respectively. XRD results indicated that the 1 wt % nanocomposite foam did not show the characteristic basal reflection of the nanoclay. The 3, 5, and 7 wt % nanocomposite foams produced a mixture of intercalated and tactoid structures. The d001-spacing of 3, 5, 7 wt % nanocomposite foams …
Estimating The Savings From Improving Pumping Plant Performance., Derrel L. Martin
Estimating The Savings From Improving Pumping Plant Performance., Derrel L. Martin
Department of Agricultural and Biological Systems Engineering: Presentations and White Papers
This brochure describes a method to estimate the cost of pumping water and to compare the amount of energy used to that for a well maintained and designed pumping plant. The results can help determine the feasibility of repairing the pumping plant.
Nutrient Transport As Affected By Rate Of Overland Flow, John E. Gilley, W. F. Sabatka, B. Eghball, David B. Marx
Nutrient Transport As Affected By Rate Of Overland Flow, John E. Gilley, W. F. Sabatka, B. Eghball, David B. Marx
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Little information is currently available concerning the effects of varying flow rate on nutrient transport by overland flow. The objective of this study was to measure the effects of overland flow rate on nutrient transport following the application of beef cattle or swine manure to plots containing 0, 2, 4, or 8 Mg ha-1 of corn residue. After addition of residue materials to 0.75 m wide by 2.0 m long plots, beef cattle or swine manure was added and the plots were then either disked or maintained in a no-till condition. Three 30 min simulated rainfall events, separated by …
Narrow Grass Hedge Effects On Nutrient Transport Following Compost Application, John E. Gilley, B. Eghball, David B. Marx
Narrow Grass Hedge Effects On Nutrient Transport Following Compost Application, John E. Gilley, B. Eghball, David B. Marx
Department of Agricultural and Biological Systems Engineering: Faculty Publications
The placement of stiff‐stemmed grass hedges on the contour along a hillslope has been shown to decrease nutrient transport in runoff. This study was conducted to measure the effectiveness of a narrow grass hedge in reducing runoff nutrient transport from plots with a range of soil nutrient values. Composted beef cattle manure was applied at dry weights of 0, 68, 105, 142, and 178 Mg ha-1 to a silty clay loam soil and then incorporated by disking. Soil samples were collected 243 days later for analysis of water‐soluble phosphorus (WSP), Bray and Kurtz No. 1 phosphorus (Bray‐1 P), NO …
Rule-Based Mamdani-Type Fuzzy Modeling Of Skin Permeability, Deepak R. Keshwani, David D. Jones, George E. Meyer, Rhonda M. Brand
Rule-Based Mamdani-Type Fuzzy Modeling Of Skin Permeability, Deepak R. Keshwani, David D. Jones, George E. Meyer, Rhonda M. Brand
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Two Mamdani type fuzzy models (three inputs–one output and two inputs–one output) were developed to predict the permeability of compounds through human skin. The models were derived from multiple data sources including laboratory data, published data bases, published statistical models, and expert opinion. The inputs to the model include information about the compound (molecular weight and octonal–H2O partition coefficient) and the application temperature. One model included all three parameters as inputs and the other model only included information about the compound. The values for mole molecular weight ranged from 30 to 600 Da. The values for the log …
Comparison Of Lipid Extraction Methods Of Food-Grade Sorghum (Sorghum Bicolor) Using Hexane, K. L. Christiansen, Curtis L. Weller, V. L. Schlegel, I. M. Dweikat
Comparison Of Lipid Extraction Methods Of Food-Grade Sorghum (Sorghum Bicolor) Using Hexane, K. L. Christiansen, Curtis L. Weller, V. L. Schlegel, I. M. Dweikat
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Much has been reported concerning sorghum phytochemicals, such as policosanols, but little literature exists on how various extraction methods might be used to optimize the recovery of such phytochemicals. The purpose of this study was to compare three extraction methods for recovery of different sorghum lipids. Lipids were extracted from whole kernel and ground Macia, a food-grade sorghum hybrid, with hexane by a Soxtec method, a refluxing method (RB), and a bench-scale recirculated solvent (RC) method. Comparisons of total lipid yield and lipid class yields extracted from the grain by each method were made. Total lipid yield for the three …
Field Slope Effects On Uniformity Of Corn Seed Spacing For Three Precision Planter Metering Systems, Corey L. Searle, Michael F. Kocher, John A. Smith, Erin E. Blankenship
Field Slope Effects On Uniformity Of Corn Seed Spacing For Three Precision Planter Metering Systems, Corey L. Searle, Michael F. Kocher, John A. Smith, Erin E. Blankenship
Department of Agricultural and Biological Systems Engineering: Faculty Publications
The effects of field slope on planter seed spacing uniformity were evaluated for three different seed metering units (cell plate, finger pick‐up, and flat plate) operating with medium round corn seed in a laboratory using the University of Nebraska planter test stand with an opto‐electronic seed spacing sensor system. The metering units included a John Deere MaxEmerge™ Plus VacuMeter row unit with the standard cell corn plate, a John Deere MaxEmerge™ Plus VacuMeter row unit with the flat plate, and a John Deere MaxEmerge™ Plus row unit with the finger pick‐up metering system. Planter seed spacing uniformity was measured using …
Visible/Near-Infrared Hyperspectral Imaging For Beef Tenderness Prediction, Govindarajan Konda Naganathan, Lauren M. Grimes, Jeyamkondan Subbiah, Chris R. Calkins, Ashok Samal, George E. Meyer
Visible/Near-Infrared Hyperspectral Imaging For Beef Tenderness Prediction, Govindarajan Konda Naganathan, Lauren M. Grimes, Jeyamkondan Subbiah, Chris R. Calkins, Ashok Samal, George E. Meyer
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Beef tenderness is an important quality attribute for consumer satisfaction. The current beef quality grading system does not incorporate a direct measure of tenderness because there is currently no accurate, rapid, nondestructive method for predicting tenderness available to the beef industry. The objective of this study was to develop and test a visible/nearinfrared hyperspectral imaging system to predict tenderness of 14-day aged, cooked beef from hyperspectral images of fresh ribeye steaks acquired at 14-day post-mortem. A push-broom hyperspectral imaging system (wavelength range: 400-1000 nm) with a diffuse-flood lighting system was developed and calibrated. Hyperspectral images of beef-steak (n = 111) …
Performance Evaluation Of Aluminum Test Cell Designed For Determining The Heat Resistance Of Bacterial Spores In Foods, H.-J. Chung, Sohan Birla, Juming Tang
Performance Evaluation Of Aluminum Test Cell Designed For Determining The Heat Resistance Of Bacterial Spores In Foods, H.-J. Chung, Sohan Birla, Juming Tang
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Thermal inactivation kinetic studies are necessary to determine heat resistances of spores in the development of new thermal processes for low-acid shelf-stable products. Most currently available sample holders used in the kinetic studies take long time to reach the target sample temperature, hence fail to provide isothermal condition. In this research, novel aluminum test cells were developed to facilitate easy loading and unloading solid and liquid food samples in a hermetically sealed 1 ml cavity to evaluate the heat resistance of bacterial spores when heated at temperatures above 100 °C. Design of the test cell was governed by minimum come-up …
Characterization Of Radio Frequency Heating Of Fresh Fruits Influenced By Dielectric Properties, Sohan Birla, S. Wang, Juming Tang, G. Tiwari
Characterization Of Radio Frequency Heating Of Fresh Fruits Influenced By Dielectric Properties, Sohan Birla, S. Wang, Juming Tang, G. Tiwari
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Because of its fast and volumetric nature, radio frequency (RF) heating has been looked upon as a way to overcome the problems associated with conventional heating methods used for disinfestation of fruits. But non-uniform heating within fruits is a major obstacle in adaptation of this technology. In this study, RF heating patterns influenced by dielectric properties (DPs) of fruits were investigated both experimentally and mathematically. A computer simulation model was developed using FEMLAB 3.4, a commercial software for solving Maxwell’s electromagnetic and Fourier’s heat transfer equations. Orange, apple, grapefruit, peach, and avocado fruits, selected for these studies were subjected to …
Review Of Career Development In Bioengineering And Biotechnology By Guruprasad Madhavan, Barbara Oakley, And Luis Kun (Editors), Springer Science+Business Media, Llc, 2008, Mark R. Riley
Department of Agricultural and Biological Systems Engineering: Faculty Publications
As an educator in biological engineering, I am often asked by students about career opportunities in this growing field. The field of biological engineering merges approaches and methodologies from a variety of traditional disciplines, and so practitioners of biological engineering can find professional opportunities in numerous areas.
The recently published book Career Development in Bioengineering and Biotechnology, (485 pages) edited by Madhavan, Oakley, and Kun, represents an ambitious undertaking with the goal of not only presenting career options and career development techniques but also addressing how the work of an individual can impact society. The book contains 71 chapters divided …
Comparative Genomic Analyses Of Copper Transporters And Cuproproteomes Reveal Evolutionary Dynamics Of Copper Utilization And Its Link To Oxygen, Perry Ridge, Yan Zhang, Vadim N. Gladyshev
Comparative Genomic Analyses Of Copper Transporters And Cuproproteomes Reveal Evolutionary Dynamics Of Copper Utilization And Its Link To Oxygen, Perry Ridge, Yan Zhang, Vadim N. Gladyshev
Vadim Gladyshev Publications
Copper is an essential trace element in many organisms and is utilized in all domains of life. It is often used as a cofactor of redox proteins, but is also a toxic metal ion. Intracellular copper must be carefully handled to prevent the formation of reactive oxygen species which pose a threat to DNA, lipids, and proteins. In this work, we examined patterns of copper utilization in prokaryotes by analyzing the occurrence of copper transporters and copper-containing proteins. Many organisms, including those that lack copper-dependent proteins, had copper exporters, likely to protect against copper ions that inadvertently enter the cell. …
Reduced Reliance On The Trace Element Selenium During Evolution Of Mammals, Alexey Lobanov, Dolph Hatfield, Vadim N. Gladyshev
Reduced Reliance On The Trace Element Selenium During Evolution Of Mammals, Alexey Lobanov, Dolph Hatfield, Vadim N. Gladyshev
Vadim Gladyshev Publications
Background: Selenium (Se) is an essential trace element that occurs in proteins in the form of selenocysteine (Sec). It is transported throughout the body in the form of Sec residues in Selenoprotein P (SelP), a plasma protein of unclear origin recently proposed as an experimental marker of dietary Se status.
Results: Here, we report that the amino-terminal domain of SelP is distantly related to ancestral bacterial thiol oxidoreductases of the thioredoxin superfamily, and that its carboxy-terminal Se transport domain may have originated in early metazoan evolution by de novo accumulation of Sec residues. Reconstruction of evolutionary changes in the Se …
In Silico Identification Of Genes Involved In Selenium Metabolism: Evidence For A Third Selenium Utilization Trait, Yan Zhang, Anton Turanov, Dolph Hatfield, Vadim N. Gladyshev
In Silico Identification Of Genes Involved In Selenium Metabolism: Evidence For A Third Selenium Utilization Trait, Yan Zhang, Anton Turanov, Dolph Hatfield, Vadim N. Gladyshev
Vadim Gladyshev Publications
Background: Selenium (Se) is a trace element that occurs in proteins in the form of selenocysteine (Sec) and in tRNAs in the form of selenouridine (SeU). Selenophosphate synthetase (SelD) is required for both utilization traits. However, previous research also revealed SelDs in two organisms lacking Sec and SeU, suggesting a possible additional use of Se that is dependent on SelD.
Results: In this study, we conducted comparative genomics and phylogenetic analyses to characterize genes involved in Se utilization. Candidate genes identified included SelA/SelB and YbbB that define Sec and SeU pathways, respectively, and NADH oxidoreductase that is predicted to generate …
A Functional Link Between Housekeeping Selenoproteins And Phase Ii Enzymes, Aniruddha Sengupta, Bradley A. Carlson, James A. Weaver, Sergey V. Novoselov, Dmitri E. Fomenko, Vadim N. Gladyshev, Dolph Hatfield
A Functional Link Between Housekeeping Selenoproteins And Phase Ii Enzymes, Aniruddha Sengupta, Bradley A. Carlson, James A. Weaver, Sergey V. Novoselov, Dmitri E. Fomenko, Vadim N. Gladyshev, Dolph Hatfield
Vadim Gladyshev Publications
Sec (selenocysteine) is biosynthesized on its tRNA and incorporated into selenium-containing proteins (selenoproteins) as the 21st amino acid residue. Selenoprotein synthesis is dependent on Sec tRNA and the expression of this class of proteins can be modulated by altering Sec tRNA expression. The gene encoding Sec tRNA (Trsp) is a single-copy gene and its targeted removal in liver demonstrated that selenoproteins are essential for proper function wherein their absence leads to necrosis and hepatocellular degeneration. In the present study, we found that the complete loss of selenoproteins in liver was compensated for by an enhanced expression of several phase II …
Memory In Food Caching Animals, Alan C. Kamil, Kristy L. Gould
Memory In Food Caching Animals, Alan C. Kamil, Kristy L. Gould
Papers in Behavior in Biological Sciences
One of the more interesting developments in the study of learning and cognition over the past 25 years has been the realization that learning and memory play an important role in the natural world of many animals. As this realization led to research into animal cognition in natural settings, it became clear that such research can make important contributions to our understanding of animal and human cognition. In this chapter, we review one of the areas of research that originally stimulated interest in the role of memory in the field, the ability of many food-storing animals to remember where they …
Plant-Like Substitutions In The Large-Subunit Carboxy Terminus Of Chlamydomonas Rubisco Increase Co2/O2 Specificity, Sriram Satagopan, Robert Spreitzer
Plant-Like Substitutions In The Large-Subunit Carboxy Terminus Of Chlamydomonas Rubisco Increase Co2/O2 Specificity, Sriram Satagopan, Robert Spreitzer
Department of Biochemistry: Faculty Publications
Background: Ribulose-1,5-bisphosphate is the rate-limiting enzyme in photosynthesis. The catalytic large subunit of the green-algal enzyme from Chlamydomonas reinhardtii is ~90% identical to the flowering-plant sequences, although they confer diverse kinetic properties. To identify the regions that may account for species variation in kinetic properties, directed mutagenesis and chloroplast transformation were used to create four amino-acid substitutions in the carboxy terminus of the Chlamydomonas large subunit to mimic the sequence of higher-specificity plant enzymes.
Results: The quadruple-mutant enzyme has a 10% increase in CO2/O2 specificity and a lower carboxylation catalytic efficiency. The mutations do not seem to …
Structural Basis Of The Transcriptional Regulation Of The Proline Utilization Regulon By Multifunctional Puta, Yuzhen Zhou, John D. Larson, Christopher A. Bottoms, Emilia C. Arturo, Michael T. Henzl, Jermaine L. Jenkins, Jay C. Nix, Donald F. Becker, John J. Tanner
Structural Basis Of The Transcriptional Regulation Of The Proline Utilization Regulon By Multifunctional Puta, Yuzhen Zhou, John D. Larson, Christopher A. Bottoms, Emilia C. Arturo, Michael T. Henzl, Jermaine L. Jenkins, Jay C. Nix, Donald F. Becker, John J. Tanner
Department of Biochemistry: Faculty Publications
The multifunctional Escherichia coli proline utilization A (PutA) flavoprotein functions both as a membrane-associated proline catabolic enzyme and as a transcriptional repressor of the proline utilization genes putA and putP. To better understand the mechanism of transcriptional regulation by PutA, we have mapped the put-regulatory region, determined a crystal structure of the PutA ribbon–helix–helix domain (PutA52, a polypeptide corresponding to residues 1–52 of E. coli PutA) complexed with DNA, and examined the thermodynamics of DNA binding to PutA52. Five operator sites, each containing the sequence motif 5′-GTTGCA-3′, were identified using gelshift analysis. Three of the sites are shown to be …
Identification Of A Consensus Dna-Binding Site For The Arabidopsis Thaliana Sbp Domain Transcription Factor, Atspl14, And Binding Kinetics By Surface Plasmon Resonance, Xinwen Liang, Tara J. Nazarenus, Julie M. Stone
Identification Of A Consensus Dna-Binding Site For The Arabidopsis Thaliana Sbp Domain Transcription Factor, Atspl14, And Binding Kinetics By Surface Plasmon Resonance, Xinwen Liang, Tara J. Nazarenus, Julie M. Stone
Department of Biochemistry: Faculty Publications
Proteins with a conserved Cys- and His-rich SQUAMOSA promoter binding protein (SBP) domain are transcription factors restricted to photosynthetic organisms that possess a novel two Zn-finger structure DNA-binding domain. Despite the fact that altered expression of some SBP-encoding genes has profound effects on organism growth and development, little is known about SBP domain protein target genes. Misexpression of the Arabidopsis thaliana AtSPL14 SBP domain gene confers resistance to programmed cell death and modifies plant architecture. A consensus DNA-binding motif for AtSPL14 was identified by systematic evolution of ligands by exponential enrichment (SELEX) or random binding site selection (RBSS). DNA recognized …
Comparative Metabolite Profiling Of Carboxylic Acids In Rat Urine By Ce-Esi Ms/Ms Through Positively Pre-Charged And 2H-Coded Derivatization, Wen-Chu Yang, Fred E. Regnier, Jiri Adamec
Comparative Metabolite Profiling Of Carboxylic Acids In Rat Urine By Ce-Esi Ms/Ms Through Positively Pre-Charged And 2H-Coded Derivatization, Wen-Chu Yang, Fred E. Regnier, Jiri Adamec
Department of Biochemistry: Faculty Publications
A new approach for the selective comparative metabolite profiling of carboxylic acids in rat urine was established using capillary electrophoresis-mass spectrometry (CE-MS) and a method for positively pre-charged and 2H-coded derivatization. Novel derivatizing reagents, N-alkyl-4-
aminomethylpyridinum iodide (alkyl=butyl, butyl-d9 or hexyl), containing quaternary amine and
stable isotope atoms (deuterium), were introduced for the derivatization of carboxylic acids. CE
separation in positive polarity showed high reproducibility (0.99 –1.32% RSD of migration time)
and eliminated problems with capillary coating known in CE-MS anion analyses. Essentially
complete ionization and increased hydrophobicity after the derivatization also enhanced MS
detection sensitivity (e.g. formic …
Stable Isotope-Coded Quaternization For Comparative Quantification Of Estrogen Metabolites By High-Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry, Wen-Chu Yang, Fred E. Regnier, Dan Silva, Jiri Adamec
Stable Isotope-Coded Quaternization For Comparative Quantification Of Estrogen Metabolites By High-Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry, Wen-Chu Yang, Fred E. Regnier, Dan Silva, Jiri Adamec
Department of Biochemistry: Faculty Publications
A fast and sensitive LC-ESI-MS method is described for the comparative quantification of 16 estrogen metabolites based on the derivatization of estrogens with a novel derivatizing reagent, Nmethyl- nicotinic acid N-hydroxysuccinimide ester (C1-NA-NHS). The process introduces a quaternary amine to the analytes, making the analytes permanently charged regardless of the pH of the HPLC mobile phase. This quaternization resulted in a highly efficient separation of 16 estrogen metabolites in 7 minutes at a detection level below 1 ng/mL. By using a deuterated derivatizing reagent (C1-d3-NA-NHS), a complete set of deuterated standards was utilized and used as internal standards in a …
Mapping The Functional Interaction Of Sco1 And Cox2 In Cytochrome Oxidase Biogenesis, Kevin Rigby, Paul A. Cobine, Oleh Khalimonchuk, Dennis R. Winge
Mapping The Functional Interaction Of Sco1 And Cox2 In Cytochrome Oxidase Biogenesis, Kevin Rigby, Paul A. Cobine, Oleh Khalimonchuk, Dennis R. Winge
Department of Biochemistry: Faculty Publications
Sco1 is implicated in the copper metallation of the CuA site in
Cox2 of cytochrome oxidase. The structure of Sco1 in the metallated
and apo-conformers revealed structural dynamics primarily
in an exposed region designated loop 8. The structural
dynamics of loop 8 in Sco1 suggests it may be an interface for
interactions with Cox17, the Cu(I) donor and/or Cox2. A series
of conserved residues in the sequence motif 217KKYRVYF223 on
the leading edge of this loop are shown presently to be important
for yeast Sco1 function. Cells harboring Y219D, R220D, V221D,
and Y222D mutant Sco1 proteins failed …
Function And Redox State Of Mitochondrial Localized Cysteine-Rich Proteins Important In The Assembly Of Cytochrome C Oxidase, Oleh Khalimonchuk, Dennis R. Winge
Function And Redox State Of Mitochondrial Localized Cysteine-Rich Proteins Important In The Assembly Of Cytochrome C Oxidase, Oleh Khalimonchuk, Dennis R. Winge
Department of Biochemistry: Faculty Publications
The cytochrome c oxidase (CcO) complex of the mitochondrial respiratory chain exists within the mitochondrial inner membrane (IM). The biogenesis of the complex is a multi-faceted process requiring multiple assembly factors that function on both faces of the IM. Formation of the two copper centers of CcO occurs within the intermembrane space (IMS) and is dependent on assembly factors with critical cysteinyl thiolates. Two classes of assembly factors exist, one group being soluble IMS proteins and the second class being proteins tethered to the IM. A common motif in the soluble assembly factors is a duplicated Cx9C sequence …
Pet191 Is A Cytochrome C Oxidase Assembly Factor In Saccharomyces Cerevisiae, Oleh Khalimonchuk, Kevin Rigby, Megan Bestwick, Fabien Pierrel, Paul A. Cobine, Dennis R. Winge
Pet191 Is A Cytochrome C Oxidase Assembly Factor In Saccharomyces Cerevisiae, Oleh Khalimonchuk, Kevin Rigby, Megan Bestwick, Fabien Pierrel, Paul A. Cobine, Dennis R. Winge
Department of Biochemistry: Faculty Publications
The twin-Cx9C motif protein Pet191 is essential for cytochrome c oxidase maturation. The motif Cys residues are functionally important and appear to be present in disulfide linkages within a large oligomeric complex associated with the mitochondrial inner membrane. The import of Pet191 differs from that of other twin-Cx9C motif class of proteins in being independent of the Mia40 pathway.